| 1. |
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| 2. |
- Paanalahti, Markku, 1961, et al.
(författare)
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Examination of the relevance of the ICF cores set for stroke by comparing with the Stroke Impact Scale.
- 2019
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Ingår i: Disability and Rehabilitation. - : Taylor & Francis. - 0963-8288 .- 1464-5165. ; 41:5, s. 508-513
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To examine if the International Classification of Functioning (ICF) core set for stoke contains problems that are relevant for the persons living with stroke as expressed in the Stroke Impact Scale (SIS).METHODS: Cross-sectional study of 242 persons with previous stroke. The agreement between the perceived problems in the SIS items and problems in the categories of Comprehensive ICF Core Set for stroke were analyzed using percent of agreement and Kappa statistic.RESULTS: The analyses between 57 items of the SIS and 31 second-level categories of the ICF were conducted. The problems in domains of "Mobility", "Activities of daily living", "Hand function", "Strength" in the SIS had moderate agreement when compared to ICF categories. The SIS domains of "Emotion" and "Communication", as well as some aspects of the "Memory" had slight or fair agreement with corresponding ICF categories. The results of the study suggest that there is acceptable agreement between persons after stroke and health professionals in the physical aspects, but rather poor agreement in the cognitive and emotional aspects of functioning.CONCLUSIONS: Health professionals do not fully capture the magnitude of emotional or social problems experienced by persons after stroke when using the ICF Core Set as a framework for evaluation. Implications for Rehabilitation The ICF Core Set for Stroke provides comprehensive list of possible health and health related outcomes for persons after stroke. Problems reported in condition-specific patient-reported outcome scales can be important in decision making in rehabilitation. Patients and health professionals tend to agree more on physical than cognitive problems. Examination of the relevance of the ICF cores set for stroke by comparing with the Stroke Impact Scale.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
- Arndt, Anton, 1968-, et al.
(författare)
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Editorial
- 2021
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Ingår i: Footwear Science. - : Taylor & Francis. - 1942-4280 .- 1942-4299. ; 13:SUP1, s. S1-S3
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 7. |
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| 8. |
- Arndt, Anton, 1968-, et al.
(författare)
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Non-uniform displacement within the Achilles tendon durig passive ankle joint motion.
- 2012
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Ingår i: Knee Surgery, Sports Traumatology, Arthroscopy. - : Springer Science and Business Media LLC. - 0942-2056 .- 1433-7347. ; 20:9, s. 1868-74
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE:An initial step in the understanding of Achilles tendon dynamics is to investigate the effects of passive motion, thereby minimising muscle activation and reducing internal joint forces. Internal tendon dynamics during passive ankle joint motion have direct implications for clinical rehabilitation protocols after Achilles tendon surgery. The aim of this study was to test the hypothesis that tendon tissue displacement is different in different layers of the Achilles tendon during controlled passive ankle joint movements.METHODS:Ultrasound imaging was conducted on the right Achilles tendon of nine healthy recreationally active males. Standardised isokinetic passive dorsi-plantar-flexion movements were performed with a total range of motion of 35°. The tendon was divided into superficial, central and deep layers in the resulting B-mode ultrasound images viewed in the sagittal plane. A block-matching speckle tracking algorithm was applied post-process, with kernels for the measurement of displacement placed in each of the layers.RESULTS:The mean (SD) displacement of the Achilles tendon during passive dorsiflexion was 8.4 (1.9) mm in the superficial layer, 9.4 (1.9) mm in the central portion and 10.4 (2.1) mm in the deep layer, respectively. In all cases, the movement of the deep layer of the tendon was greater than that of the superficial one (P < 0.01).CONCLUSIONS:These results, achieved in vivo with ultrasonographic speckle tracking, indicated complex dynamic differences in different layers of the Achilles tendon, which could have implications for the understanding of healing processes of tendon pathologies and also of normal tendon function.
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| 9. |
- Arndt, Anton, 1968-, et al.
(författare)
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The effect of a midfoot cut in the outer sole of a shoe on intrinsic foot kinematics during walking.
- 2013
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Ingår i: Footwear Science. - : Informa UK Limited. - 1942-4280 .- 1942-4299. ; 5:1, s. 63-69
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Tidskriftsartikel (refereegranskat)abstract
- Modifications in shoe outer soles are frequently made with the intention of altering biomechanics of the foot inside the shoe. These modifications are however, generally based upon intuition with little or no scientific data for support. The purpose of this study was to quantify changes in intrinsic foot segmental kinematics between walking in a neutral shoe and a shoe modified with a clear cut forming a break underneath the midfoot, approximating the Lisfrancs joint.Five healthy male subjects participated in the study. Intracortical pins were inserted under sterile conditions and local anaesthetic in nine different bones of the foot and shank. The subjects performed 10 walking trials in both a neutral, standard, flatsoled, flexible walking shoe and in the same shoe with an approximately 1 cm deep cut aligned with the subjects’ Lisfrancs joint. Material tests showed that the cut reduced midfoot shoe bending stiffness by 23% to 38% and torsional stiffness by 23% to 28%. A helical axis approach was applied for calculating the 3D rotations about relevant joints.Kinematic trajectories in the sagittal, frontal, and transverse planes were normalised to the stance phase for seven selected joints to compare rotation patterns when wearing the two shoe conditions. Although one out of 21 ranges of motion (ROM) showed a significant difference, there is strong reason to regard this as the result of a type 1 error. Apart from this no differences in ROM occurred between the shoe conditions.The low subject number reduced the statistical power of the results. However, the study indicated that outer sole modifications that may be assumed to have clear effects upon foot kinematics, do not necessarily do so.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Bjerkefors, Anna, 1966-, et al.
(författare)
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Three-Dimensional Kinematics and Power Output in Elite Para-Kayakers and Elite Able-Bodied Flat-Water Kayakers.
- 2019
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Ingår i: Journal of Applied Biomechanics. - : Human Kinetics. - 1065-8483 .- 1543-2688. ; , s. 93-100
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Tidskriftsartikel (refereegranskat)abstract
- Trunk, pelvis and leg movement are important for performance in sprint kayaking. Para-kayaking is a new Paralympic sport in which athletes with trunk and/or leg impairment compete in three classification groups. The purpose of this study was to identify how physical impairments impact on performance by examining: differences in three-dimensional joint range of motion (RoM) between 10 (4 females, 6 males) elite able-bodied kayakers and 41 (13 females, 28 males) elite para-kayakersfrom the three classification groups, and which joint angles were correlated with power output during high intensity kayak ergometer paddling. There were significant differences in RoM between the able-bodied kayakers and the three para-kayak groups for the shoulders (flexion, rotation: able-bodied kayakerspara-kayakers) and legs (hip, knee, ankle flexion: able-bodied kayakers>para-kayakers) during paddling. Furthermore, athletes with greater impairment exhibited lower trunk and leg RoM compared to those with less impairment. Significant positive correlations were observed for both males and females between power output and peak shoulder and trunk flexion, trunk and pelvis rotation RoM and hip, knee and ankle flexion RoM. This information is important for understanding how key kinematic and kinetic variables for para-kayaking performance vary between athletes from different classification groups.
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| 14. |
- da Silva, Julio Cézar Lima, et al.
(författare)
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Effect of increasing workload on knee extensor and flexor muscular activity during cycling as measured with intramuscular electromyography.
- 2018
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to describe the effect of increasing workload on individual thigh muscle activation during a 20 minute incremental cycling test. Intramuscular electromyographic signals were recorded from the knee extensors rectus femoris, vastus lateralis, vastus medialis and vastus intermedius and the knee flexors semimembranosus, semitendinosus, and the short and long heads of the biceps femoris during increasing workloads. Mean activation levels were compared over the whole pedaling cycle and the crank angles at which onset and offset of activation and peak activity occurred were identified for each muscle. These data were compared between three workloads. EMG activation level significantly increased (p<0.05) with increasing workload in the rectus femoris, vastus medialis, vastus lateralis, vastus intermedius, biceps femoris long head, semitendinosus and semimembranosus but not in the biceps femoris short head. A significant change in activation timing was found for the rectus femoris, vastus lateralis, vastus medialis and semitendinosus. Of the knee flexors only the short head of the biceps femoris had its peak activity during the upstroke phase at the two highest workloads indicating a unique contribution to knee flexion.
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| 15. |
- Dias, Caroline Pieta, et al.
(författare)
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Impaired mechanical properties of Achilles tendon in spastic stroke survivors : an observational study.
- 2019
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Ingår i: Topics in Stroke Rehabilitation. - : Taylor & Francis. - 1074-9357 .- 1945-5119. ; 26:4, s. 261-266
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The spasticity could lead to decreased functional capacity and changes in musculoskeletal tissue.OBJECTIVE: To compare the Achilles tendon properties between the affected and contralateral limbs of participants with spasticity due to stroke and the healthy subjects.METHODS: Fifteen individuals with ankle spasticity due to stroke and 15 healthy subjects were recruited. Maximal isometric ankle joint torque was obtained with an isokinetic dynamometer, and an ultrasound was used to determine tendon length, tendon cross-sectional area, and the medial gastrocnemius myotendinous junction displacement. The Achilles tendon strength, displacement, stress, strain, stiffness, and Young's modulus were obtained during a maximum voluntary isometric plantarflexion contraction.RESULTS: There were no differences between Achilles tendon length among participants. Both limbs of participants with stroke showed reduced tendon cross-sectional area (~18%) compared to healthy limb. The affected limb showed decreased tendon strength (686 ± 293.3 N), displacement (10.6 ± 1.7 mm), Young's modulus values (849 ± 235.6 MPa), and lower stiffness (196.6 ± 67.6 N/mm) compared to the contralateral limb (strength, 1357.1 ± 294.8 N; displacement, 15.2 ± 5.5 mm; Young's modulus, 1431.8 ± 301.9 MPa; stiffness, 337.5 ± 98.1 N/mm) and to the healthy limb. The contralateral limb also showed decreased tendon strength (~26.2%) and stiffness (~21.5%) compared to the healthy group.CONCLUSION: There is a decrement in Achilles tendon morphological and mechanical properties of the affected limb in individuals with spasticity due to stroke. The contralateral limb had a thinner tendon more compliant likely to physical activity reduction.
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| 16. |
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| 17. |
- Fischer, Katina Mira, et al.
(författare)
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Calcaneal adduction and eversion are coupled to talus and tibial rotation.
- 2018
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Ingår i: Journal of Anatomy. - : Wiley. - 0021-8782 .- 1469-7580. ; 233:1, s. 64-72
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to quantify isolated coupling mechanisms of calcaneal adduction/abduction and calcaneal eversion/inversion to proximal bones in vitro. The in vitro approach is necessary because in vivo both movements appear together, making it impossible to determine the extent of their individual contribution to overall ankle joint coupling. Eight fresh frozen foot-leg specimens were tested. Data describing bone orientation and coupling mechanisms between segments were obtained using bone pin marker triads. The bone movement was described in a global coordinate system to examine the coupling between the calcaneus, talus and tibia. The strength of coupling was determined by means of the slope of a linear least squares fit to an angle-angle plot. The coupling coefficients in the present study indicate that not only calcaneal eversion/inversion (coupling coefficient: 0.68 ± 0.15) but to an even greater extent calcaneal adduction/abduction (coupling coefficient: 0.99 ± 0.10) was transferred into talus and tibial rotation, highlighting the relevance of calcaneal adduction for the overall ankle joint coupling. The results of this study present the possibility that controlling calcaneal adduction/abduction can affect talus and tibial rotation and therefore the possible genesis of overuse knee injuries.
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| 18. |
- Fröberg, Åsa, et al.
(författare)
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The Effect of Ankle Foot Orthosis' Design and Degree of Dorsiflexion on Achilles Tendon Biomechanics : Tendon Displacement, Lower Leg Muscle Activation, and Plantar Pressure During Walking
- 2020
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Ingår i: Frontiers in Sports and Active Living. - : Frontiers Media S.A.. - 2624-9367. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Background: Following an Achilles tendon rupture, ankle foot orthoses (AFO) of different designs are used to protect the healing tendon. They are generally designed to protect against re-rupture by preventing undesired dorsiflexion and to prevent elongation by achieving plantarflexion in the ankle. There is limited knowledge of the biomechanical effects of different AFO designs and ankle angles on the tendon and lower leg muscles.Hypothesis: The hypothesis was that non-uniform displacement in the Achilles tendon, lower leg muscle activity, and plantar pressure distribution would be affected differently in different designs of AFO and by varying the degree of dorsiflexion limitation.Study Design: Controlled laboratory study.Methods: Ultrasound of the Achilles tendon, EMG of the lower leg muscles and plantar pressure distribution were recorded in 16 healthy subjects during walking on a treadmill unbraced and wearing three designs of AFO. Ultrasound speckle tracking was used to estimate motion within the tendon. The tested AFO designs were a rigid AFO and a dorsal brace used together with wedges and an AFO with an adjustable ankle angle restricting dorsiflexion to various degrees.Results: There were no significant differences in non-uniform tendon displacement or muscle activity between the different designs of AFO. For the rigid AFO and the adjustable AFO there was a significant reduction in non-uniform displacement within the tendon and soleus muscle activity as restriction in dorsiflexion increased.Conclusion: The degree of dorsiflexion allowed within an AFO had greater effects on Achilles tendon displacement patterns and muscle activity in the calf than differences in AFO design. AFO settings that allowed ankle dorsiflexion to neutral resulted in displacement patterns in the Achilles tendon and muscle activity in the lower leg which were close to those observed during unbraced walking.
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| 19. |
- Gago, Paulo, 1984-, et al.
(författare)
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Effects of post activation potentiation on electromechanical delay
- 2019
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Ingår i: Clinical Biomechanics. - : Elsevier. - 0268-0033 .- 1879-1271. ; 70, s. 115-122
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Tidskriftsartikel (refereegranskat)abstract
- Electromechanical delay (EMD) presumably depends upon both contractile and tensile factors. It has recently been used as an indirect measure of muscle tendon stiffness to study adaptations to stretching and training. The aim of the present study was to investigate whether contractile properties induced by a 6 s maximum voluntary isometric contraction (MVIC) could affect EMD without altering passive muscle tendon stiffness or stiffness index. Plantar flexor twitches were evoked via electrical stimulation of the tibial nerve in eight highly trained male sprinters before and after a 6 s MVIC in passive isometric or passively shortening or lengthening muscles. For each twitch, EMD, twitch contractile properties and SOLM-Wave were measured. Passive muscle tendon stiffness was measured from the slope of the relation between torque and ankle angle during controlled passive dorsal flexion and stiffness index by curve-fitting the torque angle data using a second-order polynomial function. EMD did not differ between isometric, lengthening or shortening movements. EMD was reduced by up to 11.56 ± 5.64% immediately after the MVIC and stayed depressed for up to 60 s after conditioning. Peak twitch torque and rate of torque development were potentiated by up to 119.41 ± 37.15% and 116.06 ± 37.39%, respectively. Rising time was reduced by up to 14.46 ± 7.22%. No significant changes occurred in passive muscle tendon stiffness or stiffness index. Using a conditioning MVIC, it was shown that there was an acute enhancement of contractile muscle properties as well as a significant reduction in EMD with no corresponding changes in stiffness. Therefore, caution should be taken when using and interpreting EMD as a proxy for muscle tendon stiffness.
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| 20. |
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| 21. |
- Höög, Stefan, et al.
(författare)
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Study protocol for a prospective cohort study describing the injury characteristics in elite gymnasts in TeamGym : the Swedish TeamGym Injury Cohort - STIC.
- 2024
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 14:3
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Gymnastics consists of several different disciplines, whereof TeamGym is one. TeamGym is a young discipline with sparse research. The aim of the study is to investigate the injury characteristics in Swedish elite gymnasts competing in TeamGym including training load and other physical and psychological factors associated with injury.METHODS AND ANALYSIS: The Swedish TeamGym Injury Cohort is a longitudinal prospective cohort study for 52 weeks that includes the junior (15-17 years) and senior (≥18 years) Swedish female and male national teams in TeamGym. A baseline questionnaire will be sent out in an online application (SmartaBase) regarding demographics, previous injuries, gymnastics-related factors, for example, time at elite level and psychosocial factors such as stress, athletic identity, coping skills, personality traits and coach-athlete relation. A weekly questionnaire will be sent out in SmartaBase every Sunday and will monitor injuries using the Oslo Sports Trauma Research Centre Overuse Questionnaire, gymnastics-related factors, for example, landing surfaces, stress, recovery and training load. A test battery for the lower extremity will be performed. Data for ankle dorsiflexion, hop tests and ankle plantarflexion strength/endurance will be collected.ETHICS AND DISSEMINATION: This project was approved by the Swedish Ethical Review Authority (2023-06653-01) and is performed according to the Declaration of Helsinki. The results will be published in peer-reviewed journals, scientific conferences and shared with the Swedish Gymnastics Federation.
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| 22. |
- Jacques, Tiago Canal, et al.
(författare)
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Bilateral In Vivo Neuromechanical Properties Of Thetriceps Surae And Achilles Tendon In Runners And Tri-Athletes
- 2021
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Ingår i: Journal of Biomechanics. - : Elsevier. - 0021-9290 .- 1873-2380. ; 123
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Tidskriftsartikel (refereegranskat)abstract
- Inter-limb differences in Achilles tendon mechanical, material and morphological properties have previously been described in non-athletes and attributed to the preferential use of a given limb. Achilles tendon overuse tendon injury generally initiate unilaterally and alters triceps surae activation and Achilles tendon properties. The investigation of inter-limb differences in muscle activation and tendon properties may provide directions for injury prevention in habitual runners. In this study triceps surae and Achilles tendon properties were investigated bilaterally in habitual runners during unilateral maximal isometric contractions. Morphological, mechanical and material Achilles tendon properties were assessed using isokinetic dynamometry, motion capture and ultrasonography while triceps surae activation strategies were assessed using electromyography. Lower limb preference was assessed for inter-limb comparisons using the Waterloo questionnaire. Zero and one-dimensional statistical analysis and Cohen’s d were employed to investigate possible inter-limb differences. Inter-limb associations in Achilles tendon properties and intra-limb associations between triceps surae activations were assessed using Pearson’s correlation coefficients. No differences were observed between the preferred and non-preferred limb in terms of triceps surae muscle activation amplitude and Achilles tendon properties. However, intra-limb association among triceps surae activation ratios were not identical between limbs. Runners and triathletes present similar Achilles tendons properties between limbs, and thus initial observations of unilateral changes in the Achilles tendon properties might be used as a strategy to prevent the onset of overuse tendon injury. The non-similar associations within activation ratios between limbs should be further explored since triceps surae activation strategies may alter loading of the Achilles tendon.
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| 23. |
- Jacques, Tiago Canal
(författare)
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Bilateral kinetic, kinematic, neuromechanical, and muscle-tendon properties of habitual runners
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Achilles tendon overuse-related injuries are a frequent problem to habitual runners. Such injuries occur more often unilaterally and its etiology is associated to overloading of the tendon tissue. Inter-limb differences during running are a possible cause for overload due to eventual differences in the mechanical loading provided to each limb. Furthermore, inter-limb differences in Achilles tendon properties were found in athletes due to sport-induced differences in the mechanical loading and in non-athletes due to limb preference. Currently, inter-limb differences in the Achilles properties of habitual runners is unknown. The present thesis investigated the existence of inter-limb differences in biomechanical, neuromechanical and Achilles tendon properties in habitual runners. In Study I, thirteen triathletes performed a cycle-run simulation while vertical ground reaction force (GRFv), lower limb kinematics and triceps surae and tibialis anterior activation were evaluated bilaterally during the start, mid and end stages of the 5 km running segment. In Study II, GRFv, lower limb kinematics, triceps surae and tibialis anterior activation and Achilles tendon strain were evaluated bilaterally in habitual runners at two running speeds (2.7 m.s-1 and 4.2 m.s-1). In Study III, spatiotemporal variables, vertical (kVert) and limb (kLimb) stiffness and center of mass (COM) kinematics were evaluated bilaterally in habitual runners at the same running speeds adopted in Study II. In Study IV, maximal plantar flexion isometric force, triceps surae activation and activation ratios, and Achilles tendon morphological, mechanical and material properties were evaluated bilaterally in habitual runners. In Study I the Soleus activation was lower in the preferred limb from 53.4% to 75.89% of the stance phase (p<0.01, ES range = 0.59 to 0.80) at the end stage of running. In Study II, hip extension velocity was greater in the non-preferred limb from 71% to 93% of the stance phase (p<0.01) during running at 4.2 m.s-1 while no other inter-limb differences were observed. In Study III, no inter-limb differences were observed in spatiotemporal, kVert and kLimb at investigated running speeds. However, COM horizontal velocity was greater from 67% to 87.40% of stance the phase (p<0.05, ES >0.60) when the non-preferred limb was in contact with the ground. In Study IV, no inter-limb differences were observed in triceps surae activation or Achilles tendon properties. The activation ratios of MG and SOL, however, were observed to correlate in the preferred limb only.In summary, neuromuscular and kinematic inter-limb differences were observed when healthy, non-injured habitual runners performed in running conditions similar to their ecological conditions. Moreover, the Achilles tendon seem to adapt similarly among limbs of habitual runners, while triceps surae activation strategies might differ between limbs. Findings of inter-limb differences occurring during running may result in overload during running and therefore might be implicated in the etiology of Achilles tendon overuse-related injuries in habitual runners. Findings of similar tendon properties among limbs suggest both limbs have similar chances of incurring in the injury process.Coaches and clinicians might improve current preventive strategies for Achilles tendon overuse-related injuries by monitoring tendon properties and running biomechanical and neuromuscular variables bilaterally across the season.
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| 24. |
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| 25. |
- Jacques, Tiago Canal, et al.
(författare)
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Inter-limb differences in vivo tendon behavior, kinematics, kinetics and muscle activation during running
- 2022
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Ingår i: Journal of Biomechanics. - : Elsevier. - 0021-9290 .- 1873-2380. ; 141
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Tidskriftsartikel (refereegranskat)abstract
- Overloading of tendon tissue may result in overuse tendon injuries in runners. One possible cause of overloading could be the occurrence of biomechanical inter-limb differences during running. However, scarce information exists concerning the simultaneous analysis of inter-limb differences in external and internal loading-related variables in habitual runners. In this study ground reaction force, joint kinematics, triceps surae and tibialis anterior activations, and medial gastrocnemius muscle-tendon junction displacement were assessed bilaterally during treadmill running at 2.7 m.s-1 and 4.2 m.s-1. Statistical parametric t-tests and effect sizes were calculated to identify eventual inter-limb differences across the stance phase and stride cycle. Hip flexion angle was 9° greater (p = 0.03, ES = 0.30) in the non-preferred limb during the flight phase at 4.2 m.s-1. Hip extension velocity was 45 deg.s-1 greater (p = 0.04, ES = 0.41) during ground contact and 25 deg.s-1 greater (p = 0.02, ES = 0.41) immediately after toe-off in the non-preferred limb at 4.2 m.s-1. Hip extension velocity was also 40 deg.s-1 greater (p = 0.01, ES = 0.46) in the non-preferred limb prior to touch-down at 4.2 m.s-1. Brief inter-limb differences in joint kinematics were not accompanied by inter-limb differences in variables associated to internal loading, suggesting they are unlikely to be underlying factors leading to tendon overloading in healthy non-injured runners.
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| 26. |
- Jacques, Tiago Canal, et al.
(författare)
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Running after cycling induces inter-limb differences in muscle activation but not in kinetics or kinematics.
- 2021
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Ingår i: Journal of Sports Sciences. - : Taylor & Francis Group. - 0264-0414 .- 1466-447X. ; 39:2, s. 154-160
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Tidskriftsartikel (refereegranskat)abstract
- Overuse injuries are a common problem to triathletes' population. Overuse injuries may arise from inter-limb biomechanical differences during running, but the literature lacks information regarding inter-limb differences in triathletes. In this study inter-limb differences were investigated in injury-free triathletes during the running portion of a simulated cycle-run transition. Thirteen triathletes performed a 5 km run preceded by a 20 min cycling trial at 70% of maximal power output. During the Start, Mid and End stages of running, kinetic, kinematic and muscle activation variables were compared between the preferred and non-preferred limbs across the stance phase. A statistical parametric mapping analysis showed no differences between limbs when considering kinetic and kinematic variables (p > 0.05, ES<0.60). A lower soleus activation was observed in the preferred limb (p < 0.05, ES>0.60) from 53.40-75.9% of the stance phase at the End stage of running. In conclusion, inter-limb differences in kinetic or kinematic variables may not represent a risk for overloading in triathletes. However, inter-limb differences in triceps surae activation during running after cycling may represent one potential factor leading to overuse injuries in triathletes and should be further investigated.
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| 27. |
- Körting, Clara, et al.
(författare)
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In vivo muscle morphology comparison in post-stroke survivors using ultrasonography and diffusion tensor imaging.
- 2019
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Skeletal muscle architecture significantly influences the performance capacity of a muscle. A DTI-based method has been recently considered as a new reference standard to validate measurement of muscle structure in vivo. This study sought to quantify muscle architecture parameters such as fascicle length (FL), pennation angle (PA) and muscle thickness (tm) in post-stroke patients using diffusion tensor imaging (DTI) and to quantitatively compare the differences with 2D ultrasonography (US) and DTI. Muscle fascicles were reconstructed to examine the anatomy of the medial gastrocnemius, posterior soleus and tibialis anterior in seven stroke survivors using US- and DTI-based techniques, respectively. By aligning the US and DTI coordinate system, DTI reconstructed muscle fascicles at the same scanning plane of the US data can be identified. The architecture parameters estimated based on two imaging modalities were further compared. Significant differences were observed for PA and tm between two methods. Although mean FL was not significantly different, there were considerable intra-individual differences in FL and PA. On the individual level, parameters measured by US agreed poorly with those from DTI in both deep and superficial muscles. The significant differences in muscle parameters we observed suggested that the DTI-based method seems to be a better method to quantify muscle architecture parameters which can provide important information for treatment planning and to personalize a computational muscle model.
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| 28. |
- Leardini, Alberto, et al.
(författare)
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ISB recommendations for skin-marker-based multi-segment foot kinematics.
- 2021
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Ingår i: Journal of Biomechanics. - : Elsevier. - 0021-9290 .- 1873-2380. ; 125
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Tidskriftsartikel (refereegranskat)abstract
- The foot is anatomically and functionally complex, and thus an accurate description of intrinsic kinematics for clinical or sports applications requires multiple segments. This has led to the development of many multi-segment foot models for both kinematic and kinetic analyses. These models differ in the number of segments analyzed, bony landmarks identified, required marker set, defined anatomical axes and frames, the convention used to calculate joint rotations and the determination of neutral positions or other offsets from neutral. Many of these models lack validation. The terminology used is inconsistent and frequently confusing. Biomechanical and clinical studies using these models should use established references and describe how results are obtained and reported. The International Society of Biomechanics has previously published proposals for standards regarding kinematic and kinetic measurements in biomechanical research, and in this paper also addresses multi-segment foot kinematics modeling. The scope of this work is not to prescribe a particular set of standard definitions to be used in all applications, but rather to recommend a set of standards for collecting, calculating and reporting relevant data. The present paper includes recommendations for the overall modeling and grouping of the foot bones, for defining landmarks and other anatomical references, for addressing the many experimental issues in motion data collection, for analysing and reporting relevant results and finally for designing clinical and biomechanical studies in large populations by selecting the most suitable protocol for the specific application. These recommendations should also be applied when writing manuscripts and abstracts.
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| 29. |
- Liljedahl, Johanna B, et al.
(författare)
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Para-cycling race performance in different sport classes.
- 2021
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Ingår i: Disability and Rehabilitation. - : Taylor & Francis. - 0963-8288 .- 1464-5165. ; 43:24, s. 3440-3444
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The para-cycling classification system, consisting of five classes (C1-C5) for bicycling (C5 athletes having least impairments), is mostly based on expert-opinion rather than scientific evidence. The aim of this study was to determine the differences in race performance between para-cycling classes. Methods: From official results of the men's 1 km time trials for classes C1-C5 of seven Union Cycliste Internationale World Championships and Paralympics, median race speed of the five fastest athletes in each class was calculated (n = 175). Para-cycling results were expressed as a percentage of able-bodied performance using race results from the same years (n = 35). To assess differences between consecutive classes, Kruskal-Wallis tests with Mann-Whitney U post hoc tests were performed, correcting for multiple testing (p < 0.013). Results: Para-cyclists in C1 reached 75% (median ± interquartile range = 44.8 ± 4.2 km/h) and in C5 90% (53.5 ± 2.9 km/h) of able-bodied race speed (59.4 ± 0.9 km/h). Median race speed between consecutive classes was significantly different (χ2 = 142.6, p < 0.01), except for C4 (52.1 ± 2.8 km/h) and C5 (U = 447.0, p = 0.05). Conclusion: Current para-cycling classification does not clearly differentiate between classes with least impairments.IMPLICATIONS FOR REHABILITATIONThe current classification system is not evidence-based and does not clearly differentiate between relevant groups of para-cyclists.An evidence-based para-cycling classification system is essential for a fair and equitable competition.Fair competition will make it more interesting and increase participation.Para-cycling can inspire everyone with and even those without disabilities to be physically active.
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| 30. |
- Liljedahl, Johanna, et al.
(författare)
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Isometric, dynamic, and manual muscle strength measures and their association with cycling performance in elite para-cyclists.
- 2023
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Ingår i: American Journal of Physical Medicine & Rehabilitation. - : Wolters Kluwer. - 0894-9115 .- 1537-7385. ; 102:5, s. 461-467
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Para-cycling classification aims to generate fair competition by discriminating between levels of activity limitation. This study investigated the relationship between lower limb Manual Muscle Tests (MMT) with ratio-scaled measures of isometric and dynamic strength, and of the ratio-scaled measures with cycling performance.DESIGN: Fifty-six para-cyclists (44 males, 12 females) with leg impairments performed isometric and dynamic strength tests: leg push and pull, and an all-out 20 s sprint. MMT results were obtained from the classification database (n = 21) and race speeds from time trials (n = 54).RESULTS: Regression analyses showed significant associations of MMT with isometric push (R2 = .49), dynamic push (R2 = .35), and dynamic pull (R2 = .28). Isometric strength was significantly correlated with dynamic push (ρ = .63) and pull (ρ = .54). The isometric and dynamic tests were significantly associated with sprint power and race speed (R2 = .16-.50).CONCLUSION: The modified MMT and ratio-scaled measures were significantly associated. The significant relation of isometric and dynamic strength with sprint power and race speed maps the impact of lower limb impairments on para-cycling performance. MMT and the isometric and dynamic measures show potential for use in para-cycling classification.
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| 31. |
- Liljedahl, Johanna
(författare)
-
Towards evidence-based classification in para-cycling
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of classification in Paralympic sport is to minimize the impact of impairment on the outcome of competition. The aim of this thesis was to investigate the impact of different types of impairments on para-cycling performance to develop an evidence-based classification system in the para-cycling C (bicycling) and T (tricycling) divisions.This thesis is based on four articles. The first article examined differences in race performance between para-cycling classes by comparing track race results. The second article evaluated leg strength measures in para-cyclists with musculoskeletal impairments. The third article investigated leg coordination and leg strength and the association with para-cycling performance in para-cyclists with hypertonia, ataxia, or athetosis. The fourth article aimed to gather consensus on para-cycling classification issues and to identify research priorities within para-cycling, by consulting a panel with expertise within para-cycling and para-sport.This thesis has identified performance characteristics in para-cyclists with musculoskeletal and coordination impairments, and suggested tests with potential to be used in para-cycling classification to assess muscle strength and coordination. The results indicate that the classes for athletes with the least impairments, as well as the classes for athletes with impaired coordination, need to be further investigated.
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| 32. |
- Liu, Anmin, et al.
(författare)
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The Effect of an Antipronation Foot Orthosis on Ankle and Subtalar Kinematics
- 2012
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 44:12, s. 2384-91
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION/PURPOSE:The aim of this study was to describe the effect of an anti pronation foot orthosis on motion of the heel relative to the leg and explore the individual contributions of the ankle and subtalar joints to this effect.METHODS:Five subjects were investigated using invasive intracortical pins to track the movement of the tibia, talus and calcaneus during walking with and without a foot orthosis.RESULTS:The anti pronation foot orthosis produced small and unsystematic reductions in eversion and abduction of the heel relative to the leg at various times during stance. Changes in calcaneus-tibia motion were comparable to those described in the literature (1-3°). Changes at both the ankle and subtalar joints contributed to this orthotic effect. However, the nature and scale of changes was highly variable between subjects. Peak angular position, range of motion and angular velocity in frontal and transverse planes were affected to different degrees in different subjects. In some cases changes occurred mainly at the ankle, in other cases changes occurred mainly at the subtalar joint.CONCLUSION:The changes in ankle and subtalar kinematics in response to the foot orthosis contradict existing orthotic paradigms that assume that changes occur only at the subtalar joint. The kinematic changes due to the orthosis are indicative of a strong interaction between the often common function of the ankle and subtalar joints.
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| 33. |
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| 34. |
- Nooijen, Carla F J, et al.
(författare)
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The relation between sprint power and road time trial performance in elite para-cyclists.
- 2021
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Ingår i: Journal of Science and Medicine in Sport. - : Elsevier. - 1440-2440 .- 1878-1861. ; 24:11, s. 1193-1198
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Whilst cycling performance has been studied extensively, very little is known about the performance of para-cyclists. This study assessed the relation between sprint power and road time trial performance in elite para-cyclists, and whether this relation differed based on impairment type and type of bike used.DESIGN: Cross-sectional.METHODS: During international para-cycling events, 168 athletes (88 bicycles, 17 tricycles, 56 recumbent handbikes and 7 kneeling handbikes) performed 20-s sport-specific sprint tests (mean power output (POmean) W), and their road time trial performance (average speed (km/h)) was taken from the official results. Multilevel regression models to assess the relation of sprint with time trial performance were composed for i. leg-cyclists: bicycle and tricycle and ii. arm-cyclists: recumbent- and kneeling handbike, adjusted for identified confounders. Furthermore, impairment type (categorized as i) muscle power/range of motion, ii) limb deficiency/leg length difference, and iii) coordination) and bike type were tested as effect modifiers.RESULTS: POmean ranged from 303 ± 12 W for recumbent handcyclists to 482 ± 156 W for bicyclists. POmean was significantly related to time trial performance, for both leg-cyclists (β = 0.010, SE = 0.003, p < 0.01) and arm-cyclists (β = 0.029; SE = 0.005, p < 0.01), and impairment type and bike type were not found to be effect modifiers.CONCLUSIONS: Sprint power was related to road time trial performance in all para-cyclists, with no differences found in this relation based on impairment type nor bike type. For those competing on a bicycle, tricycle, recumbent- or kneeling handbike, sprint tests might therefore be useful to predict or monitor time trial performance.
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| 35. |
- Péter, Annamária, et al.
(författare)
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Comparing Surface and Fine-Wire Electromyography Activity of Lower Leg Muscles at Different Walking Speeds.
- 2019
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Ingår i: Frontiers in Physiology. - : Frontiers Media S.A.. - 1664-042X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Ankle plantar flexor muscles are active in the stance phase of walking to propel the body forward. Increasing walking speed requires increased plantar flexor excitation, frequently assessed using surface electromyography (EMG). Despite its popularity, validity of surface EMG applied on shank muscles is mostly unclear. Thus, we examined the agreement between surface and intramuscular EMG at a range of walking speeds. Ten participants walked overground at slow, preferred, fast, and maximum walking speeds (1.01 ± 0.13, 1.43 ± 0.19, 1.84 ± 0.23, and 2.20 ± 0.38 m s-1, respectively) while surface and fine-wire EMG activities of flexor hallucis longus (FHL), soleus (SOL), medial gastrocnemius (MG) and lateral gastrocnemius (LG), and tibialis anterior (TA) muscles were recorded. Surface and intramuscular peak-normalised EMG amplitudes were compared for each muscle and speed across the stance phase using Statistical Parametric Mapping. In FHL, we found differences around peak activity at all speeds except fast. There was no difference in MG at any speed or in LG at slow and preferred speeds. For SOL and LG, differences were seen in the push-off phase at fast and maximum walking speeds. In SOL and TA, surface EMG registered activity during phases in which intramuscular EMG indicated inactivity. Our results suggest that surface EMG is generally a suitable method to measure MG and LG EMG activity across several walking speeds. Minimising cross-talk in FHL remains challenging. Furthermore, SOL and TA muscle onset/offset defined by surface EMG should be interpreted cautiously. These findings should be considered when recording and interpreting surface EMG of shank muscles in walking.
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| 36. |
- Péter, Annamária, et al.
(författare)
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Effect of footwear on intramuscular EMG activity of plantar flexor muscles in walking.
- 2020
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Ingår i: Journal of Electromyography & Kinesiology. - : Elsevier. - 1050-6411 .- 1873-5711. ; 55
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Tidskriftsartikel (refereegranskat)abstract
- One of the purposes of footwear is to assist locomotion, but some footwear types seem to restrict natural foot motion, which may affect the contribution of ankle plantar flexor muscles to propulsion. This study examined the effects of different footwear conditions on the activity of ankle plantar flexors during walking. Ten healthy habitually shod individuals walked overground in shoes, barefoot and in flip-flops while fine-wire electromyography (EMG) activity was recorded from flexor hallucis longus (FHL), soleus (SOL), and medial and lateral gastrocnemius (MG and LG) muscles. EMG signals were peak-normalised and analysed in the stance phase using Statistical Parametric Mapping (SPM). We found highly individual EMG patterns. Although walking with shoes required higher muscle activity for propulsion than walking barefoot or with flip-flops in most participants, this did not result in statistically significant differences in EMG amplitude between footwear conditions in any muscle (p > 0.05). Time to peak activity showed the lowest coefficient of variation in shod walking (3.5, 7.0, 8.0 and 3.4 for FHL, SOL, MG and LG, respectively). Future studies should clarify the sources and consequences of individual EMG responses to different footwear.
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| 37. |
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| 38. |
- Peter, Annamaria, et al.
(författare)
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Impact of footwear type and walking speed on ankle plantar flexor fine-wire electromyographic activity
- 2018
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Ingår i: Sport science at the cutting edge.
-
Konferensbidrag (refereegranskat)abstract
- INTRODUCTION:Ankle plantar flexors substantially contribute to propulsion in human walking, and their relative contributions may be affected by the type of footwear used. In this study, we aimed to examine plantar flexor fine-wire electromyography (wEMG) activity in different footwear types and barefoot walking. We further examined the effect of walking speed on the relative activity of ankle plantar flexors.METHODS:Nine healthy people volunteered to this study (five males) with two sessions. In session 1, participants were familiarized to the study protocol. In session 2, electrical activity of flexor hallucis longus (FHL), soleus (SOL), medial and lateral gastrocnemius (MG and LG) muscles were measured with wEMG during eight overground walking tasks: preferred speed walking with shoes, barefoot and with flip-flops; with shoes: 30% slower and faster than preferred speed walking with shoes, and maximum walking speed; walking barefoot and with flip-flops at the same speed as preferred speed walking with shoes (matched speed). Then they performed maximal isometric plantar flexion contractions and maximal big toe flexions superimposed on ankle plantar flexion (MVICs) in an isokinetic dynamometer for wEMG normalization. Root mean square activity was calculated in the push-off phase of individual step cycles based on ground reaction force data. The relative contribution of each muscle to propulsion was calculated as: (mean RMS value %MVIC of the given muscle / mean RMS value %MVIC of all muscles) * 100. Cohen’s d±90% confidence intervals were calculated to define the magnitude of differences.RESULTS:In all muscles, wEMG activity increased with speed. With increasing speed the relative contribution to propulsion increased in FHL (from 19 to 22%), did not change in SOL (32%), decreased in MG (from 32 to 25%) and increased in LG (from 18 to 21%). There were no differences between preferred and matched barefoot walking speed or wEMG activity level (d range = 0.06-0.17). wEMG activity for all muscles was lower during matched barefoot walking than preferred speed walking with shoes (7-10% MVIC, d range=0.31-0.47). Flip-flop data are under analysis.CONCLUSION:We found that relative wEMG activity of the examined muscles was affected by speed and absence or presence of shoes. During barefoot walking, wEMG activity of plantar flexor muscles was lower than during shod walking at the same speed, which presumably means that shod walking limits the contribution of intrinsic foot muscles to propulsion, which should be further examined.REFERENCES:1 Murley GS, Menz HB, Landorf KB. (2014). Gait & Posture, 39(4), 1080-5.2 Goldmann JP, Potthast W, Brüggemann GP. (2013). Footwear Sci, 5 (1): 19-25.3 Franklin et al., Gait & Posture. 60: 1-5, 2018.CONTACT:annamaria.a.peter@jyu.fi
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| 39. |
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| 40. |
- Peter, A, et al.
(författare)
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Surface compared to fine-wire electromyography activity of lower leg muscles at different walking speeds.
- 2019
-
Konferensbidrag (refereegranskat)abstract
- Summary: Surface and fine-wire electromyography activity of flexor hallucis longus, soleus, medial and lateral gastrocnemius and tibialis anterior muscles was measured simultaneously during walking at four different speeds to examine whether signals recorded with the two methods exhibit similar signal characteristics. We found statistical differences between methods at all walking speeds in soleus and tibialis anterior, at all speeds except fast walking in flexor hallucis longus, and at faster speeds in lateral gastrocnemius. No differences were found in medial gastrocnemius at any speed or in lateral gastrocnemius at slow and preferred speed walking.
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| 41. |
- Rosén, Johanna
(författare)
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Performance determinants and classification in paracanoe
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Valid classification systems are vital for Paralympic sports in order to minimise the impact of impairment on sports performance. To achieve valid classification, each Paralympic sport must develop evidence-based classification systems by examining the impact of impairment on key performance determinants. The aim of this thesis was to examine the impact of impairment on key performance determinants in para va’a and para kayak. Additional aims were to examine the reliability of the para va’a classification system and the validity of the para kayak classification system.In studies I and III, three-dimensional (3D) kinematic data from the arms, trunk and legs as well as force from the paddle was collected. Ten non-impaired va’a and 44 para va’a athletes participated in study I and 10 non-impaired kayak and 41 para kayak athletes participated in study III. In study II, three international classifier teams, each comprised of a medical and technical classifier, classified 12 para va’a athletes using the new trunk, leg and on-water classification test batteries and class allocation for para va’a. In study IV, 3D kinematics of the trunk, legs and paddle as well as forces at the footrest, seat and paddle were measured in 17 para kayak athletes with above knee (AK) (n=11) or below knee (BK) (n=6) amputation.The main findings were:If para va'a athletes have full trunk function, the level of leg impairment does not affect the performance in terms of paddling force (Study I).The inter-rater reliability of the evidence-based classification system for para va’a was excellent with no discrepancies between the classifier teams in class allocation and minor discrepancies in individual tests (Study II).The differences between the three para kayak classes were in line with the definition of the classes in the new evidence-based classification system for para kayak. In addition, no significant correlations were seen between power output and joint variables in trunk or legs for two of the three classes indicating that these classes are valid (Study III).Differences between athletes with AK and BK amputation were seen for variables concerning the hip joint. No differences were however seen between the groups in paddle performance variables (Study IV).In conclusion, this thesis has described how athletes with different impairment differ in key performance determinants for para va’a and para kayak. The results of the thesis also gave indications that the new evidence-based classification system for para va’a is reliable and that the new evidence-based classification system for para kayak is valid in regard to two of the three classes.
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| 42. |
- Rosén, Johanna S, et al.
(författare)
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Interrater Reliability of the New Sport-Specific Evidence-Based Classification System for Para Va'a.
- 2020
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Ingår i: Adapted Physical Activity Quarterly. - : Human Kinetics. - 0736-5829 .- 1543-2777. ; 37:3, s. 241-252
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to examine the interrater reliability of a new evidence-based classification system for Para Va'a. Twelve Para Va'a athletes were classified by three classifier teams each consisting of a medical and a technical classifier. Interrater reliability was assessed by calculating intraclass correlation for the overall class allocation and total scores of trunk, leg, and on-water test batteries and by calculating Fleiss's kappa and percentage of total agreement in the individual tests of each test battery. All classifier teams agreed with the overall class allocation of all athletes, and all three test batteries exhibited excellent interrater reliability. At a test level, agreement between classifiers was almost perfect in 14 tests, substantial in four tests, moderate in four tests, and fair in one test. The results suggest that a Para Va'a athlete can expect to be allocated to the same class regardless of which classifier team conducts the classification.
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| 43. |
- Rosén, Johanna S, et al.
(författare)
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Kinematic and kinetic performance variables during paddling among para-kayak athletes with unilateral above or below knee amputation
- 2022
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Ingår i: Sports Biomechanics. - : Taylor & Francis. - 1476-3141 .- 1752-6116.
-
Tidskriftsartikel (refereegranskat)abstract
- In para-kayak, athletes with unilateral above knee amputation (AK) and athletes with below knee amputation (BK) compete in the same class. This has been questioned since previous research have shown that the legs are important for paddling performance. The purpose was therefore to examine differences in kinematic and kinetic performance variables between AK and BK para-kayak athletes and the amputated (A) and non-amputated (NA) sides. Eleven AK and six BK athletes on international level participated. 3D kinematic and kinetic data were collected for the body, seat, footrest and paddle during kayak ergometer paddling. There were no significant differences between the groups in main performance variables such as power output or paddle force. Differences between the groups were only seen in the hip joint in flexion range of motion, flexion and extension angular velocity and flexion moment where BK demonstrated larger values. The NA side demonstrated greater values compared to the A side in posterior force at the seat and in hip flexion moment. As there were no significant differences between the groups in the majority of the examined key performance variables, the results suggest that athletes with unilateral AK and BK amputation may be able to compete in the same class.
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| 44. |
- Rosén, Johanna S, et al.
(författare)
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The impact of impairment on kinematic and kinetic variables in Va'a paddling : Towards a sport-specific evidence-based classification system for Para Va'a.
- 2019
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Ingår i: Journal of Sports Sciences. - : Taylor & Francis. - 0264-0414 .- 1466-447X. ; 37:17, s. 1942-1950
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Tidskriftsartikel (refereegranskat)abstract
- Para Va'a is a new Paralympic sport in which athletes with trunk and/or leg impairment compete over 200 m. The purpose of this study was to examine the impact of impairment on kinematic and kinetic variables during Va'a ergometer paddling. Ten able-bodied and 44 Para Va'a athletes with impairments affecting: trunk and legs (TL), legs bilaterally (BL) or leg unilaterally (UL) participated. Differences in stroke frequency, mean paddling force, and joint angles and correlation of the joint angles with paddling force were examined. Able-bodied demonstrated significantly greater paddling force as well as knee and ankle flexion ranges of movement (ROM) on the top hand paddling side compared to TL, BL and UL. Able-bodied, BL and UL demonstrated greater paddling force and trunk flexion compared to TL, and UL demonstrated larger bottom hand paddling side knee and ankle flexion ROM compared to BL. Significant positive correlations were observed for both male and female athletes between paddling force and all trunk flexion angles and ROM in the trunk and pelvis rotation and bottom hand paddling side hip, knee and ankle flexion. The results of this study are important for creating an evidence-based classification system for Para Va'a.
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| 45. |
- Sandamas, Paul Nicolas
(författare)
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Athletic Sprint Start Biomechanics : Investigations into the relationships between three dimensional starting technique, first step width and performance
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The block and early acceleration phase plays a very important role in the overall outcome of athletic sprint events. During this part of the race it is commonly observed that sprinters use a lower-body technique that involves the swing leg crossing medially in front of the athlete followed by wide steps. These wide initial steps give the impression that the legs are flailing out to the side. Some coaches believe that this action could be inefficient and thus should be curtailed. However, there is limited knowledge about this movement pattern and its relation to performance.Therefore, the overall aim of this thesis was to help elucidate from a biomechanical perspective a) the fundamental underlying kinematic and mechanical basis to this technique and b) how both performance and muscular contributions to propulsion would be affected when step width was restricted.A cross sectional study design was used to examine specific kinematic and kinetic variables from 11 competitive sprinters (9 male, 2 female) performing maximum effort 15 m sprint starts. Three-dimensional kinematics, ground reaction force and electromyographical data were recorded from the block phase to the end of the 1st stance phase. Each athlete performed five trials with their natural technique and five trials inside a 0.3 m wide lane. A 15-segment, full-body model and a 37 degrees of freedom full-body musculoskeletal model were created and used to calculate relevant variables/parameters. Normalised average horizontal external power was used as the performance measure.A combination of pelvis list and rotation (but not hip adduction) was found to be coupled with the thigh of the swing leg moving medially during the single push phase. In the unrestricted width trials, pelvic list range of motion and medial impulses correlated positively with step width but step width was not found to be related to performance. When step width was restricted, a more forward pointing normalised average ground reaction force vector was seen but lower body muscular contributions to acceleration were reduced and no immediate improvement to performance was found.The primary kinematic reason behind the lower body posture the sprinters adopt during the block phase whereby the swing leg moves medially in front of the body is caused by a combination of three dimensional pelvis rotations rather than simply hip internal rotation/or adduction of the swing leg. Trying to reduce pelvic range of motion or minimising the flailing leg motion is unlikely to lead to an improvement in performance. Therefore, the notion that this technique is inefficient, was not supported by this study.
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| 46. |
- Sandamas, Paul, et al.
(författare)
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The effect of a reduced first step width on starting block and first stance power and impulses during an athletic sprint start.
- 2019
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Ingår i: Journal of Sports Sciences. - : Taylor & Francis. - 0264-0414 .- 1466-447X. ; 37:9, s. 1046-1054
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated how manipulating first step width affects 3D external force production, centre of mass (CoM) motion and performance in athletic sprinting. Eight male and 2 female competitive sprinters (100m PB: 11.03 ± 0.36 s male and 11.6 ± 0.45 s female) performed 10 maximal effort block starts. External force and three-dimensional kinematics were recorded in both the block and first stance phases. Five trials were performed with the athletes performing their preferred technique (Skating) and five trials with the athletes running inside a 0.3 m lane (Narrow). By reducing step width from a mean of 0.31 ± 0.06 m (Skating) to 0.19 ± 0.03 m (Narrow), reductions were found between the two styles in medial block and medial 1st stance impulses, 1st stance anterior toe-off velocity and mediolateral motion of the CoM. No differences were found in block time, step length, stance time, average net resultant force vector, net anteroposterior impulse nor normalised external power. Step width correlated positively with medial impulse but not with braking nor net anteroposterior impulse. Despite less medially directed forces and less mediolateral motion of the CoM in the Narrow trials, no immediate improvement to performance was found by restricting step width.
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| 47. |
- Sandamas, Paul, et al.
(författare)
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The relationships between pelvic range of motion, step width and performance during an athletic sprint start
- 2020
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Ingår i: Journal of Sports Sciences. - : Routledge. - 0264-0414 .- 1466-447X. ; 38:19, s. 2200-2207
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Tidskriftsartikel (refereegranskat)abstract
- The aims of this study were (a) to describe the kinematics underlying the phenomenon of the knee of the swing leg passing medially in front of the athlete during the single push (SP) phase of the block sprint start, and (b) to determine the relationships between block phase pelvis range of motion (RoM), 1st step width and block phase performance. Three-dimensional kinematic data (250 Hz) were collected from eleven competitive sprinters (100 m PB: 11.17 ± 0.41) performing maximal effort block starts. The joint angles of the rear hip with respect to the pelvis and the pelvis segment angles with respect to the laboratory coordinate system were calculated during the block start phase to the end of the 1st stance. A combination of pelvis list and rotation (not hip adduction) was coupled with the thigh of the swing leg moving medially during the SP phase. A very high positive correlation was found between pelvic list RoM and 1st step width (r = 0.799, p = 0.003). No other significant correlations were found. Attempting to reduce pelvic RoM or changing frontal and transverse plane hip joint angles to minimise medial thigh motion is unlikely to lead to an improvement to performance.
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| 48. |
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| 49. |
- Spiegl, Ondrej, et al.
(författare)
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Comparison of lightweight and traditional figure skating blades, a prototype blade with integrated damping system and a running shoe in simulated figure skating landings and vertical countermovement jumps, and evaluation of dampening properties of the prototype blade.
- 2022
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Ingår i: Sports Biomechanics. - Abingdon : Taylor & Francis. - 1476-3141 .- 1752-6116. ; , s. 1-22
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Tidskriftsartikel (refereegranskat)abstract
- To date, there is no empirical evidence suggesting greater jump heights or cushioned landings when using figure skating (FS) blades of different mass and design. This study examined the effect of lightweight (Gold Seal Revolution from John Wilson) and traditional (Apex Supreme from Jackson Ultima and Volant from Riedell) blades, a new prototype blade with an integrated damping system (damping blade) in two different damping configurations, and running shoes (Runfalcon from Adidas) on kinetics and kinematics during simulated on-ice landings from 0.6 m and maximal countermovement jumps on synthetic ice, and measured dampening properties of the damping blade. Seventeen participants executed trials in the six footwear conditions blinded to the different blades and acted as their own control for statistical comparison. There were no differences between the lightweight and traditional blades on the maximal vertical ground reaction force during the landing. Image analysis showed a damping effect in the damping blade that significantly decreased the landing load for all participants (mean 4.38 ± 0.68 bodyweight) (p ≤ 0.006), on average between 10.1 and 14.3% compared to lightweight and traditional blades (4.87 ± 1.01 to 5.11 ± 0.88 bodyweight). The maximal jump height achieved was the same in all FS blades.
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| 50. |
- Spiegl, Ondrej, et al.
(författare)
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The effects of new Edea and Graf figure skating boots and used Graf boots on the kinetics and kinematics of landing after simulated on-ice jumps
- 2019
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Ingår i: Footwear Science. - : Routledge. - 1942-4280 .- 1942-4299. ; 11:2, s. 121-129
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Tidskriftsartikel (refereegranskat)abstract
- An increase in training intensity and the number of active participants and competitors in figure skating has been accompanied by an increasing frequency of injuries. The aim of this study was to investigate whether different brands of skates as well as the usage of the skates modify the kinetics and kinematics of the landing impact from a jump. New Graf Edmonton (NG), old used Graf Edmonton (OG) and new Edea Concerto (NE) skates were compared. Twelve participants completed six jump trials from 30 cm and 50 cm high boxes, respectively in all three skates and landed on a section of artificial ice placed on a laboratory floor. Landing kinematics (Oqus4 system, Qualisys, Sweden) and kinetics (force plate: Kistler, Switzerland; insoles: Pedar, Novel, Germany) were examined. Each participant acted as their own control for statistical comparison between the skates. The results confirmed that the kinetics and kinematics of the landing are affected by wearing different skates. During landing impacts in NG, participants had significantly greater dorsiflexion at initial contact (IC) and peak dorsiflexion of the ankle, peak flexion of the knee and also greater in-skate plantar forces (PF) than in NE, which may increase the risk of injury. In OG, participants had significantly greater peak flexion of knee and longer time from IC to first peak dorsiflexion (TP) of the ankle than in NG. The differences observed may be due to the different construction designs, such as height of the heel, used materials, and stiffness of the skates, which may affect injury occurrence.
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