| 1. |
- Paanalahti, Markku, 1961, et al.
(author)
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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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In: Disability and Rehabilitation. - : Taylor & Francis. - 0963-8288 .- 1464-5165. ; 41:5, s. 508-513
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Journal article (peer-reviewed)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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| 2. |
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| 3. |
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| 4. |
- Begon, Mickaël, et al.
(author)
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Can optimal marker weightings improve thoracohumeral kinematics accuracy?
- 2015
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In: Journal of Biomechanics. - : Elsevier BV. - 0021-9290 .- 1873-2380. ; 48:10, s. 2019-2025
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Journal article (peer-reviewed)abstract
- Local and global optimization algorithms have been developed to estimate joint kinematics to reducing soft movement artifact (STA). Such algorithms can include weightings to account for different STA occur at each marker. The objective was to quantify the benefit of optimal weighting and determine if optimal marker weightings can improve humerus kinematics accuracy. A pin with five reflective markers was inserted into the humerus of four subjects. Seven markers were put on the skin of the arm. Subjects performed 38 different tasks including arm elevation, rotation, daily-living tasks, and sport activities. In each movement, mean and peak errors in skin- vs. pins-orientation were reported. Then, optimal marker weightings were found to best match skin- and pin-based orientation. Without weighting, the error of the arm orientation ranged from 1.9° to 17.9°. With weighting, 100% of the trials were improved and the average error was halved. The mid-arm markers weights were close to 0 for three subjects. Weights of a subject applied to the others for a given movement, and weights of a movement applied to others for a given subject did not systematically increased accuracy of arm orientation. Without weighting, a redundant set of marker and least square algorithm improved accuracy to estimate arm orientation compared to data of the literature using electromagnetic sensor. Weightings were subject- and movement-specific, which reinforces that STA are subject- and movement-specific. However, markers on the deltoid insertion and on lateral and medial epicondyles may be preferred if a limited number of markers is used.
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| 5. |
- Bjerkefors, Anna, et al.
(author)
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Three-dimensional kinematic analysis and power output of elite flat-water kayakers.
- 2018
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In: Sports Biomechanics. - : Informa UK Limited. - 1476-3141 .- 1752-6116. ; 17:3, s. 414-427
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Journal article (peer-reviewed)abstract
- The purpose was to examine power output and three-dimensional (3D) kinematic variables in the upper limbs, lower limbs and trunk in elite flat-water kayakers during kayak ergometer paddling. An additional purpose was to analyse possible changes in kinematics with increased intensity and differences between body sides. Six male and four female international level flat-water kayakers participated. Kinematic and kinetic data were collected during three tasks; low (IntL), high (IntH) and maximal (IntM) intensities. No differences were observed in any joint angles between body sides, except for shoulder abduction. Significantly greater range of motion (RoM) values were observed for IntH compared to IntL and for IntM compared to IntL in trunk and pelvis rotation, and in hip, knee and ankle flexion. The mean maximal power output was 610 ± 65 and 359 ± 33 W for the male and female athletes, respectively. The stroke frequencies were significantly different between all intensities (IntL 59.3 ± 6.3; IntH 108.0 ± 6.8; IntM 141.7 ± 18.4 strokes/min). The results showed that after a certain intensity level, the power output must be increased by other factors than increasing the joint angular RoM. This information may assist coaches and athletes to understand the relationship between the movement of the kayaker and the paddling power output.
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| 6. |
- Bjerkefors, Anna, 1966-, et al.
(author)
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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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In: Journal of Applied Biomechanics. - : Human Kinetics. - 1065-8483 .- 1543-2688. ; , s. 93-100
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Journal article (peer-reviewed)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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| 7. |
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| 8. |
- Couch, Fergus J., et al.
(author)
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Identification of four novel susceptibility loci for oestrogen receptor negative breast cancer
- 2016
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In: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 7:11375, s. 1-13
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Journal article (peer-reviewed)abstract
- Common variants in 94 loci have been associated with breast cancer including 15 loci with genome-wide significant associations (P<5 x 10(-8)) with oestrogen receptor (ER)-negative breast cancer and BRCA1-associated breast cancer risk. In this study, to identify new ER-negative susceptibility loci, we performed a meta-analysis of 11 genome-wide association studies (GWAS) consisting of 4,939 ER-negative cases and 14,352 controls, combined with 7,333 ER-negative cases and 42,468 controls and 15,252 BRCA1 mutation carriers genotyped on the iCOGS array. We identify four previously unidentified loci including two loci at 13q22 near KLF5, a 2p23.2 locus near WDR43 and a 2q33 locus near PPIL3 that display genome-wide significant associations with ER-negative breast cancer. In addition, 19 known breast cancer risk loci have genome-wide significant associations and 40 had moderate associations (P<0.05) with ER-negative disease. Using functional and eQTL studies we implicate TRMT61B and WDR43 at 2p23.2 and PPIL3 at 2q33 in ER-negative breast cancer aetiology. All ER-negative loci combined account for similar to 11% of familial relative risk for ER-negative disease and may contribute to improved ER-negative and BRCA1 breast cancer risk prediction.
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| 9. |
- da Silva, Julio Cézar Lima, et al.
(author)
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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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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:8
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Journal article (peer-reviewed)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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| 10. |
- da Silva, Julio Cézar Lima, et al.
(author)
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Quadriceps and hamstring muscle activity during cycling as measured with intramuscular electromyography.
- 2016
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In: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 116:9, s. 1807-1817
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Journal article (peer-reviewed)abstract
- PURPOSE: The aim of this study was to describe thigh muscle activation during cycling using intramuscular electromyographic recordings of eight thigh muscles, including the biceps femoris short head (BFS) and the vastus intermedius (Vint).METHODS: Nine experienced cyclists performed an incremental test (start at 170 W and increased by 20 W every 2 min) on a bicycle ergometer either for a maximum of 20 min or to fatigue. Intramuscular electromyography (EMG) of eight muscles and kinematic data of the right lower limb were recorded during the last 20 s in the second workload (190 W). EMG data were normalized to the peak activity occurring during this workload. Statistical significance was assumed at p ≤ 0.05.RESULTS: The vastii showed a greater activation during the 1st quadrant compared to other quadrants. The rectus femoris (RF) showed a similar activation, but with two bursts in the 1st and 4th quadrants in three subjects. This behavior may be explained by the bi-articular function during the cycling movement. Both the BFS and Vint were activated longer than, but in synergy with their respective agonistic superficial muscles.CONCLUSION: Intramuscular EMG was used to verify muscle activation during cycling. The activation pattern of deep muscles (Vint and BFS) could, therefore, be described and compared to that of the more superficial muscles. The complex coordination of quadriceps and hamstring muscles during cycling was described in detail.
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| 11. |
- Dal Maso, Fabien, et al.
(author)
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Distance between rotator cuff footprints and the acromion, coracoacromial ligament, and coracoid process during dynamic arm elevations : Preliminary observations : Technical and measurement report
- 2016
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In: Manual Therapy. - : Elsevier BV. - 1356-689X .- 1532-2769. ; 25, s. 94-99
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Journal article (peer-reviewed)abstract
- Background The objective of this study was to provide preliminary measures of the distance between the supraspinatus, infraspinatus, and subscapularis footprints and the acromion, coracoacromial ligament, and coracoid process, during dynamic arm elevations through the entire range-of-motion.
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| 12. |
- Dal Maso, Fabien, et al.
(author)
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Glenohumeral translations during range-of-motion movements, activities of daily living, and sports activities in healthy participants.
- 2015
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In: Clinical Biomechanics. - : Elsevier BV. - 0268-0033 .- 1879-1271. ; 30:9, s. 1002-1007
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Journal article (peer-reviewed)abstract
- BACKGROUND: Glenohumeral translations have been mainly investigated during static poses while shoulder rehabilitation exercises, activities of daily living, and sports activities are dynamic. Our objective was to assess glenohumeral translations during shoulder rehabilitation exercises, activities of daily living, and sports activities to provide a preliminary analysis of glenohumeral arthrokinematics in a broad range of dynamic tasks.METHODS: Glenohumeral translations were computed from trajectories of markers fitted to intracortical pins inserted into the scapula and the humerus. Two participants (P1 and P2) performed full range-of-motion movements including maximum arm elevations and internal-external rotations rehabilitation exercises, six activities of daily living, and five sports activities.FINDINGS: During range-of-motion movements, maximum upward translation was 7.5mm (P1) and 4.7mm (P2). Upward translation during elevations was smaller with the arm internally (3.6mm (P1) and 2.9mm (P2)) than neutrally (4.2mm (P1) and 3.7mm (P2)) and externally rotated (4.3mm (P1) and 4.3mm (P2)). For activities of daily living and sports activities, only anterior translation during reach axilla for P1 and upward translation during ball throwing for P2 were larger than the translation measured during range-of-motion movements (108% and 114%, respectively).INTERPRETATION: While previous electromyography-based studies recommended external rotation during arm elevation to minimize upward translation, measures of glenohumeral translations suggest that internal rotation may be better. Similar amplitude of translation during ROM movement and sports activities suggests that large excursions of the humeral head may be caused not only by fast movements, but also by large amplitude movements.
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| 13. |
- Darabi, H, et al.
(author)
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Fine scale mapping of the 17q22 breast cancer locus using dense SNPs, genotyped within the Collaborative Oncological Gene-Environment Study (COGs)
- 2016
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In: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6, s. 32512-
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Journal article (peer-reviewed)abstract
- Genome-wide association studies have found SNPs at 17q22 to be associated with breast cancer risk. To identify potential causal variants related to breast cancer risk, we performed a high resolution fine-mapping analysis that involved genotyping 517 SNPs using a custom Illumina iSelect array (iCOGS) followed by imputation of genotypes for 3,134 SNPs in more than 89,000 participants of European ancestry from the Breast Cancer Association Consortium (BCAC). We identified 28 highly correlated common variants, in a 53 Kb region spanning two introns of the STXBP4 gene, that are strong candidates for driving breast cancer risk (lead SNP rs2787486 (OR = 0.92; CI 0.90–0.94; P = 8.96 × 10−15)) and are correlated with two previously reported risk-associated variants at this locus, SNPs rs6504950 (OR = 0.94, P = 2.04 × 10−09, r2 = 0.73 with lead SNP) and rs1156287 (OR = 0.93, P = 3.41 × 10−11, r2 = 0.83 with lead SNP). Analyses indicate only one causal SNP in the region and several enhancer elements targeting STXBP4 are located within the 53 kb association signal. Expression studies in breast tumor tissues found SNP rs2787486 to be associated with increased STXBP4 expression, suggesting this may be a target gene of this locus.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Dias, Caroline Pieta, et al.
(author)
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Impaired mechanical properties of Achilles tendon in spastic stroke survivors : an observational study.
- 2019
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In: Topics in Stroke Rehabilitation. - : Taylor & Francis. - 1074-9357 .- 1945-5119. ; 26:4, s. 261-266
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Journal article (peer-reviewed)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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| 18. |
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| 19. |
- Dork, T, et al.
(author)
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Two truncating variants in FANCC and breast cancer risk
- 2019
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In: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1, s. 12524-
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Journal article (peer-reviewed)abstract
- Fanconi anemia (FA) is a genetically heterogeneous disorder with 22 disease-causing genes reported to date. In some FA genes, monoallelic mutations have been found to be associated with breast cancer risk, while the risk associations of others remain unknown. The gene for FA type C, FANCC, has been proposed as a breast cancer susceptibility gene based on epidemiological and sequencing studies. We used the Oncoarray project to genotype two truncating FANCC variants (p.R185X and p.R548X) in 64,760 breast cancer cases and 49,793 controls of European descent. FANCC mutations were observed in 25 cases (14 with p.R185X, 11 with p.R548X) and 26 controls (18 with p.R185X, 8 with p.R548X). There was no evidence of an association with the risk of breast cancer, neither overall (odds ratio 0.77, 95%CI 0.44–1.33, p = 0.4) nor by histology, hormone receptor status, age or family history. We conclude that the breast cancer risk association of these two FANCC variants, if any, is much smaller than for BRCA1, BRCA2 or PALB2 mutations. If this applies to all truncating variants in FANCC it would suggest there are differences between FA genes in their roles on breast cancer risk and demonstrates the merit of large consortia for clarifying risk associations of rare variants.
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| 20. |
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| 21. |
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| 22. |
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| 23. |
- Ferreira, MA, et al.
(author)
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Genome-wide association and transcriptome studies identify target genes and risk loci for breast cancer
- 2019
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In: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 1741-
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Journal article (peer-reviewed)abstract
- Genome-wide association studies (GWAS) have identified more than 170 breast cancer susceptibility loci. Here we hypothesize that some risk-associated variants might act in non-breast tissues, specifically adipose tissue and immune cells from blood and spleen. Using expression quantitative trait loci (eQTL) reported in these tissues, we identify 26 previously unreported, likely target genes of overall breast cancer risk variants, and 17 for estrogen receptor (ER)-negative breast cancer, several with a known immune function. We determine the directional effect of gene expression on disease risk measured based on single and multiple eQTL. In addition, using a gene-based test of association that considers eQTL from multiple tissues, we identify seven (and four) regions with variants associated with overall (and ER-negative) breast cancer risk, which were not reported in previous GWAS. Further investigation of the function of the implicated genes in breast and immune cells may provide insights into the etiology of breast cancer.
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| 24. |
- Figlioli, G, et al.
(author)
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The FANCM:p.Arg658* truncating variant is associated with risk of triple-negative breast cancer
- 2019
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In: NPJ breast cancer. - : Springer Science and Business Media LLC. - 2374-4677. ; 5, s. 38-
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Journal article (peer-reviewed)abstract
- Breast cancer is a common disease partially caused by genetic risk factors. Germline pathogenic variants in DNA repair genes BRCA1, BRCA2, PALB2, ATM, and CHEK2 are associated with breast cancer risk. FANCM, which encodes for a DNA translocase, has been proposed as a breast cancer predisposition gene, with greater effects for the ER-negative and triple-negative breast cancer (TNBC) subtypes. We tested the three recurrent protein-truncating variants FANCM:p.Arg658*, p.Gln1701*, and p.Arg1931* for association with breast cancer risk in 67,112 cases, 53,766 controls, and 26,662 carriers of pathogenic variants of BRCA1 or BRCA2. These three variants were also studied functionally by measuring survival and chromosome fragility in FANCM−/− patient-derived immortalized fibroblasts treated with diepoxybutane or olaparib. We observed that FANCM:p.Arg658* was associated with increased risk of ER-negative disease and TNBC (OR = 2.44, P = 0.034 and OR = 3.79; P = 0.009, respectively). In a country-restricted analysis, we confirmed the associations detected for FANCM:p.Arg658* and found that also FANCM:p.Arg1931* was associated with ER-negative breast cancer risk (OR = 1.96; P = 0.006). The functional results indicated that all three variants were deleterious affecting cell survival and chromosome stability with FANCM:p.Arg658* causing more severe phenotypes. In conclusion, we confirmed that the two rare FANCM deleterious variants p.Arg658* and p.Arg1931* are risk factors for ER-negative and TNBC subtypes. Overall our data suggest that the effect of truncating variants on breast cancer risk may depend on their position in the gene. Cell sensitivity to olaparib exposure, identifies a possible therapeutic option to treat FANCM-associated tumors.
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| 25. |
- Fischer, Katina Mira, et al.
(author)
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Calcaneal adduction and eversion are coupled to talus and tibial rotation.
- 2018
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In: Journal of Anatomy. - : Wiley. - 0021-8782 .- 1469-7580. ; 233:1, s. 64-72
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Journal article (peer-reviewed)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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| 26. |
- Fischer, Katina Mira, et al.
(author)
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Calcaneal adduction in slow running : three case studies using intracortical pins.
- 2017
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In: Footwear Science. - : Informa UK Limited. - 1942-4280 .- 1942-4299. ; 9:2, s. 87-93
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Journal article (peer-reviewed)abstract
- The aim of this study was to use bone-anchored markers to determine the bone movement of calcaneal adduction, eversion and tibial rotation in a global coordinate system and to describe the relationship of calcaneal adduction to tibial rotation. Furthermore, the amount of overall intra-foot motion in the transverse plane (metatarsal I relative to calcaneus) and its relationship to calcaneal adduction were quantified. Three male participants were assessed during slow running. A 10-camera motion analysis system was used for kinematic data capture of global bone orientations in 3D space for all bones of the foot and ankle complex. For the description of intrinsic articulations within the foot, the skeletal motion relative to the adjacent proximal segment in the transverse plane was calculated. Furthermore, the time of occurrence of maximum values was determined. The findings showed that calcaneal adduction of all participants amounted to 7.8 ± 4.8°, which exceeded the magnitude of calcaneal eversion (4.7 ± 3.1°). Although the inter-participant variability was high, considerable overall intra-foot motion in the transverse plane of the metatarsal I relative to the calcaneus was found to be 4.7 ± 4.6° and could be qualitatively related to calcaneal adduction. The present data provide evidence that next to calcaneal eversion, calcaneal adduction seems related to tibial rotation. Furthermore, overall intra-foot motion in the transverse plane seems related to calcaneal adduction. Controlling calcaneal adduction and overall intra-foot motion in the transverse plane may be a mechanism to control excessive tibial rotation in runners who suffer from overuse knee injuries. These findings could be used to provide an additional approach for future motion-control footwear design to control rearfoot adduction or overall within-foot motion.
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| 27. |
- Fröberg, Asa, et al.
(author)
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High variability in strain estimation errors when using a commercial ultrasound speckle tracking algorithm on tendon tissue
- 2016
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In: Acta Radiologica. - : Sage Publications. - 0284-1851 .- 1600-0455. ; 57:10, s. 1223-1229
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Journal article (peer-reviewed)abstract
- Background: Ultrasound speckle tracking offers a non-invasive way of studying strain in the free Achilles tendon where no anatomical landmarks are available for tracking. This provides new possibilities for studying injury mechanisms during sport activity and the effects of shoes, orthotic devices, and rehabilitation protocols on tendon biomechanics. Purpose: To investigate the feasibility of using a commercial ultrasound speckle tracking algorithm for assessing strain in tendon tissue. Material and Methods: A polyvinyl alcohol (PVA) phantom, three porcine tendons, and a human Achilles tendon were mounted in a materials testing machine and loaded to 4% peak strain. Ultrasound long-axis cine-loops of the samples were recorded. Speckle tracking analysis of axial strain was performed using a commercial speckle tracking software. Estimated strain was then compared to reference strain known from the materials testing machine. Two frame rates and two region of interest (ROI) sizes were evaluated. Results: Best agreement between estimated strain and reference strain was found in the PVA phantom (absolute error in peak strain: 0.21 +/- 0.08%). The absolute error in peak strain varied between 0.72 +/- 0.65% and 10.64 +/- 3.40% in the different tendon samples. Strain determined with a frame rate of 39.4Hz had lower errors than 78.6Hz as was the case with a 22mm compared to an 11mm ROI. Conclusion: Errors in peak strain estimation showed high variability between tendon samples and were large in relation to strain levels previously described in the Achilles tendon.
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| 28. |
- Fröberg, Åsa, et al.
(author)
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Altered patterns of displacement within the Achilles tendon following surgical repair
- 2017
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In: Knee Surgery, Sports Traumatology, Arthroscopy. - : Springer Science and Business Media LLC. - 0942-2056 .- 1433-7347. ; 25:6, s. 1857-1865
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Journal article (peer-reviewed)abstract
- Ultrasound speckle tracking was used to compare tendon deformation patterns between uninjured and surgically repaired Achilles tendons at 14-27-month follow-up. The hypothesis was that the non-homogenous displacement pattern previously described in uninjured tendons, where displacement within deep layers of the tendons exceeds that of superficial layers, is altered following tendon rupture and subsequent surgical repair. In the first part of this study, an in-house-developed block-matching speckle tracking algorithm was evaluated for assessment of displacement on porcine flexor digitorum tendons. Displacement data from speckle tracking were compared to displacement data from manual tracking. In the second part of the study, eleven patients with previous unilateral surgically treated Achilles tendon rupture were investigated using ultrasound speckle tracking. The difference in superficial and deep tendon displacement was assessed. Displacement patterns in the surgically repaired and uninjured tendons were compared during passive motion (Thompson's squeeze test) and during active ankle dorsiflexion. The difference in peak displacement between superficial and deep layers was significantly (p < 0.01) larger in the uninjured tendons as compared to the surgically repaired tendons both during Thompson's test (-0.7 +/- 0.2 mm compared to -0.1 +/- 0.1 mm) and active dorsiflexion (3.3 +/- 1.1 mm compared to 0.3 +/- 0.2 mm). The evaluation of the speckle tracking algorithm showed correlations of r ae 0.89 between displacement data acquired from speckle tracking and the reference displacement acquired from manual tracking. Speckle tracking systematically underestimated the magnitude of displacement with coefficients of variation of less than 11.7%. Uninjured Achilles tendons display a non-uniform displacement pattern thought to reflect gliding between fascicles. This pattern was altered after a mean duration of 19 +/- 4 months following surgical repair of the tendon indicating that fascicle sliding is impaired. This may affect modulation of the action between different components of the triceps surae, which in turn may affect force transmission and tendon elasticity resulting in impaired function and risk of re-rupture.
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| 29. |
- Gago, Paulo, 1984-, et al.
(author)
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Effects of post activation potentiation on electromechanical delay
- 2019
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In: Clinical Biomechanics. - : Elsevier. - 0268-0033 .- 1879-1271. ; 70, s. 115-122
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Journal article (peer-reviewed)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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| 30. |
- Gago, Paulo, 1984-
(author)
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Post activation potentiation : Modulating factors and mechanisms for muscle performance
- 2016
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Doctoral thesis (other academic/artistic)abstract
- Introduction: Acute enhancements of muscle contractile properties and performance subsequent to a maximal or near maximal conditioning contraction are often termed post activation potentiation (PAP). Although still controversial, PAP is commonly linked to enhancements in the myosin regulatory light chain phosphorylation, leading to improvements in the excitation–contraction coupling. The PAP seen after a conditioning task often coexists with fatigue and is known to depend on strength level, muscle fiber type and age. Less is known about how factors such as static and dynamic changes in muscle length affect PAP, and on the relative contribution of contractile and tensile components to PAP.Aim: To enhance our understanding of how, and under what conditions, a single maximal isometric contraction affects plantar flexor muscle contractile performance, and other muscle tendon properties, in power athletes.Methods: Supramaximal twitches were evoked via electrical stimulation of the tibial nerve of athletes before and on several occasions after a 6-second maximal voluntary isometric contraction (6-s MVIC) in both static muscle, and during passive muscle lengthening and shorting at different angular velocities. Several contractile variables were measured from the twitches. The effects of a 6-s MVIC on Achilles tendon stiffness was calculated from torque and ultrasonography based measurements of tendon length at two submaximal contraction intensities. Overall stiffness index was calculated by analyzing the passive lengthening torque/angle curve.Results: A single MVIC enhanced muscle contractile properties and electromechanical delay for up to 5 minutes. Plantar flexor twitch variables such as peak twitch, rate of torque development and rate of torque relaxation were enhanced during shortening compared to lengthening muscle actions, and in an extended as compared to a flexed knee position. Achilles tendon stiffness and overall stiffness index were not significantly modulated by a single 6-s MVIC.Conclusion: The results of this thesis imply that functional enhancements from a 6-s conditioning MVIC would mainly come from improvements in contractile rather than tensile components. Stiffness changes should be monitored in future PAP-related studies since they may still occur after more extensive conditioning protocols than the current one. Improvements in contractile components subserving muscle strength after a conditioning MVIC suggests that enhancements in muscle power after a conditioning task should be greatest in fast concentric muscle actions, though still present in muscle lengthening. Conditioning should be performed in a position where full activation is easy to achieve and tailored to mach an athlete or group of athlete’s current status and characteristics, maximizing performance in a specific sport event.
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| 39. |
- Hollestelle, Antoinette, et al.
(author)
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No clinical utility of KRAS variant rs61764370 for ovarian or breast cancer
- 2016
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In: Gynecologic Oncology. - : Elsevier BV. - 0090-8258 .- 1095-6859. ; 141:2, s. 386-401
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Journal article (peer-reviewed)abstract
- Objective Clinical genetic testing is commercially available for rs61764370, an inherited variant residing in a KRAS 3′ UTR microRNA binding site, based on suggested associations with increased ovarian and breast cancer risk as well as with survival time. However, prior studies, emphasizing particular subgroups, were relatively small. Therefore, we comprehensively evaluated ovarian and breast cancer risks as well as clinical outcome associated with rs61764370. Methods Centralized genotyping and analysis were performed for 140,012 women enrolled in the Ovarian Cancer Association Consortium (15,357 ovarian cancer patients; 30,816 controls), the Breast Cancer Association Consortium (33,530 breast cancer patients; 37,640 controls), and the Consortium of Modifiers of BRCA1 and BRCA2 (14,765 BRCA1 and 7904 BRCA2 mutation carriers). Results We found no association with risk of ovarian cancer (OR = 0.99, 95% CI 0.94-1.04, p = 0.74) or breast cancer (OR = 0.98, 95% CI 0.94-1.01, p = 0.19) and results were consistent among mutation carriers (BRCA1, ovarian cancer HR = 1.09, 95% CI 0.97-1.23, p = 0.14, breast cancer HR = 1.04, 95% CI 0.97-1.12, p = 0.27; BRCA2, ovarian cancer HR = 0.89, 95% CI 0.71-1.13, p = 0.34, breast cancer HR = 1.06, 95% CI 0.94-1.19, p = 0.35). Null results were also obtained for associations with overall survival following ovarian cancer (HR = 0.94, 95% CI 0.83-1.07, p = 0.38), breast cancer (HR = 0.96, 95% CI 0.87-1.06, p = 0.38), and all other previously-reported associations. Conclusions rs61764370 is not associated with risk of ovarian or breast cancer nor with clinical outcome for patients with these cancers. Therefore, genotyping this variant has no clinical utility related to the prediction or management of these cancers.
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| 42. |
- Jiao, Xiang, et al.
(author)
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PHIP - a novel candidate breast cancer susceptibility locus on 6q14.1
- 2017
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In: Oncotarget. - : IMPACT JOURNALS LLC. - 1949-2553. ; 8:61, s. 102769-102782
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Journal article (peer-reviewed)abstract
- Most non-BRCA1/2 breast cancer families have no identified genetic cause. We used linkage and haplotype analyses in familial and sporadic breast cancer cases to identify a susceptibility locus on chromosome 6q. Two independent genome-wide linkage analysis studies suggested a 3 Mb locus on chromosome 6q and two unrelated Swedish families with a LOD > 2 together seemed to share a haplotype in 6q14.1. We hypothesized that this region harbored a rare high-risk founder allele contributing to breast cancer in these two families. Sequencing of DNA and RNA from the two families did not detect any pathogenic mutations. Finally, 29 SNPs in the region were analyzed in 44,214 cases and 43,532 controls from BCAC, and the original haplotypes in the two families were suggested as low-risk alleles for European and Swedish women specifically. There was also some support for one additional independent moderate-risk allele in Swedish familial samples. The results were consistent with our previous findings in familial breast cancer and supported a breast cancer susceptibility locus at 6q14.1 around the PHIP gene.
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| 45. |
- Körting, Clara, et al.
(author)
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In vivo muscle morphology comparison in post-stroke survivors using ultrasonography and diffusion tensor imaging.
- 2019
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In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9:1
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Journal article (peer-reviewed)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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| 46. |
- Lanferdini, Fábio J, et al.
(author)
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Differences in Pedaling Technique in Cycling : A Cluster Analysis.
- 2016
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In: International Journal of Sports Physiology and Performance. - : Human Kinetics. - 1555-0265 .- 1555-0273. ; 11:7, s. 959-964
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Journal article (peer-reviewed)abstract
- PURPOSE: To employ cluster analysis to assess if cyclists would opt for different strategies in terms of neuromuscular patterns when pedaling at the power output of their second ventilatory threshold (POVT2) compared with cycling at their maximal power output (POMAX).METHODS: Twenty athletes performed an incremental cycling test to determine their power output (POMAX and POVT2; first session), and pedal forces, muscle activation, muscle-tendon unit length, and vastus lateralis architecture (fascicle length, pennation angle, and muscle thickness) were recorded (second session) in POMAX and POVT2. Athletes were assigned to 2 clusters based on the behavior of outcome variables at POVT2 and POMAX using cluster analysis.RESULTS: Clusters 1 (n = 14) and 2 (n = 6) showed similar power output and oxygen uptake. Cluster 1 presented larger increases in pedal force and knee power than cluster 2, without differences for the index of effectiveness. Cluster 1 presented less variation in knee angle, muscle-tendon unit length, pennation angle, and tendon length than cluster 2. However, clusters 1 and 2 showed similar muscle thickness, fascicle length, and muscle activation. When cycling at POVT2 vs POMAX, cyclists could opt for keeping a constant knee power and pedal-force production, associated with an increase in tendon excursion and a constant fascicle length.CONCLUSIONS: Increases in power output lead to greater variations in knee angle, muscle-tendon unit length, tendon length, and pennation angle of vastus lateralis for a similar knee-extensor activation and smaller pedal-force changes in cyclists from cluster 2 than in cluster 1.
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| 47. |
- Lawrenson, Kate, et al.
(author)
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Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus
- 2016
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Journal article (peer-reviewed)abstract
- A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 × 10-20), ER-negative BC (P=1.1 × 10-13), BRCA1-associated BC (P=7.7 × 10-16) and triple negative BC (P-diff=2 × 10-5). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 × 10-3) and ABHD8 (P<2 × 10-3). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3′-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk.
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| 48. |
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| 49. |
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| 50. |
- Maiwald, Christian, et al.
(author)
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The effect of intracortical bone pin application on kinetics and tibiocalcaneal kinematics of walking gait
- 2017
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In: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 52, s. 129-134
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Journal article (peer-reviewed)abstract
- Gait analysis using bone anchored markers requires local anaesthesia, which may affect subjects gait patterns.Kinetic and kinematic variables were collected using two protocols (skin vs. bone anchored markers).No systematic differences were found between the two protocols.We conclude that the validity of the recorded variables is not affected by local anaesthesia.Bone anchored markers using intracortical bone pins are one of the few available methods for analyzing skeletal motion during human gait in-vivo without errors induced by soft tissue artifacts. However, bone anchored markers require local anesthesia and may alter the motor control and motor output during gait. The purpose of this study was to examine the effect of local anesthesia and the use of bone anchored markers on typical gait analysis variables. Five subjects were analyzed in two different gait analysis sessions. In the first session, a protocol with skin markers was used. In the second session, bone anchored markers were added after local anesthesia was applied. For both sessions, three dimensional infrared kinematics of the calcaneus and tibia segments, ground reaction forces, and plantar pressure data were collected. 95% confidence intervals and boxplots were used to compare protocols and assess the data distribution and data variability for each subject. Although considerable variation was found between subjects, within-subject comparison of the two protocols revealed non-systematic effects on the target variables. Two of the five subjects walked at reduced gait speed during the bone pin session, which explained the between-session differences found in kinetic and kinematic variables. The remaining three subjects did not systematically alter their gait pattern between the two sessions. Results support the hypothesis that local anesthesia and the presence of bone pins still allow a valid gait pattern to be analyzed.
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