| 1. |
- Röijezon, Ulrik, et al.
(författare)
-
An Initial Study on the Coordination of Rod and Line Hauling Movements in Distance Fly Casting
- 2017
-
Ingår i: Annals of Applied Sport Science. - : Asian Exercise and Sport Science Association. - 2476-4981 .- 2322-4479. ; 5:2, s. 61-72
-
Tidskriftsartikel (refereegranskat)abstract
- Background. The double haul is a unique feature of single-handed fly casting and is used in both fly fishing and fly casting competition. The movement behaviour during the double haul has not been investigated in previous research.Objectives. Describe the coordination of the rod and line hauling movements during distance fly casting.Methods. Elite fly casters performed distance casting with four different fly rod and fly line set-ups used in fly fishing and fly casting competition. Rod and hauling movements were measured with a 3D motion analysis system.Results. The rod and line hauling movements were coordinated in an order whereby peak translational speed of the rod occurs prior to the peak speed of the angular rotation of the rod, and the peak speed of the angular rotation of the rod occurs prior to the peak speed of the line haul. This was consistent for all cast sequences, i.e., the back and forward false casts and the delivery cast, and for all four equipment set-ups, i.e., a shooting-head line cast with a relatively stiff fly rod and a long-belly line cast with three different fly rods with different stiffness and action curves. Results also showed differences in movement coordination between cast sequences and rod and line set-ups.Conclusion. Among elite casters, single-handed fly casting with double haul is coordinated in an order of events whereby the peak speed occurs first for the translation of the rod, then for the rotation of the rod and finally for the line haul.
|
|
| 2. |
- Richter, Hans O., et al.
(författare)
-
Long-term adaptation to neck/shoulder pain and perceptual performance in a hand laterality motor imagery test
- 2010
-
Ingår i: Perception. - : Sage Publications. - 0301-0066 .- 1468-4233. ; 39:1, s. 119-130
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of neck/shoulder pain on the performance in a hand laterality motor imagery test was studied. Responses to the Cooper and Shepard (1975, Journal of Experimental Psychology: Human Perception and Performance 104 48–56) hand laterality test were explored in twenty-four individuals with chronic non-specific neck pain and twenty-one subjects with chronic neck pain of traumatic origin (whiplash-associated disorder). Twenty-two controls were also included in the study. Digitalised right- or left-hand stimuli were presented at five different stimulus angles (0°, 45° laterally, 90° laterally, 135° laterally, and 180°). The experimental task was to decide the laterality as fast and accurately as possible. The performance, both reaction time (RT) and accuracy, of the two experimental groups was contrasted with that of the control group. The main results revealed that the subjects afflicted with whiplash injury on the average exhibited a faster response pattern than symptom-free healthy controls. Despite their musculoskeletal deficits and experience of pain these volunteers also exhibited a preserved speed–accuracy tradeoff. Longer duration of time with symptoms of neck pain was, moreover, associated with progressively faster RTs. These results point to perceptual learning and may reflect different stages of adaptation to neck pain.
|
|
| 3. |
|
|
| 4. |
- Strandkvist, Viktor, et al.
(författare)
-
Hand grip strength is strongly associated with lower limb strength but only weakly with postural control in community-dwelling older adults
- 2021
-
Ingår i: Archives of gerontology and geriatrics (Print). - : Elsevier. - 0167-4943 .- 1872-6976. ; 94
-
Tidskriftsartikel (refereegranskat)abstract
- Background:Hand grip strength is frequently used as a measurement of muscle strength, especially among older adults. Muscle strength is only one of the many components in postural control and it is currently unclear to what extent hand grip strength is associated with postural control. The aim was to analyze the association between hand grip strength and lower limb muscle strength, and postural control among older adults.Methods:Forty-five community-dwelling individuals over 70 years of age provided isometric hand grip strength and lower limb strength (including hip extension and abduction, knee flexion and extension, and ankle dorsiflexion and plantarflexion), as well as postural control measurements. In the latter, center of pressure excursions were recorded for quiet stance and limits of stability tests on a force plate. Orthogonal projection of latent structures regression models were used to analyze associations between hand grip strength and lower limb strength as well as postural control, respectively.Results:Lower limb strength explained 74.4% of the variance in hand grip strength. All lower limb muscle groups were significantly associated with hand grip strength. In a corresponding model, postural control measured with center of pressure excursions explained 20.7% of the variance in a statistically significant, albeit weak, model.Conclusions:These results support that hand grip strength is a valid method to estimate lower limb strength among older adults on a group level. However, strength measurements seem insufficient as a substitute for measuring postural control, and therefore specific balance tests are necessary.
|
|
| 5. |
- Röijezon, Ulrik
(författare)
-
Projekt: Hälsa och prestation vid Musicerande
- 2012
-
Annan publikation (populärvet., debatt m.m.)abstract
- Projektet involverar studier av muskuloskeletala besvär och påverkan på rörelsekontroll hos musiker. Finansiering sker bland annat via Post Doc anslag från Forskningsrådet för Arbetsliv och Socialvetenskap (FAS).
|
|
| 6. |
- Strong, Andrew, et al.
(författare)
-
Properties of knee joint position sense tests after anterior cruciate ligament injury : A systematic review and meta-analysis
- 2021
-
Ingår i: The Orthopaedic Journal of Sports Medicine. - : Sage Publications. - 2325-9671. ; 9:8
-
Forskningsöversikt (refereegranskat)abstract
- Background: Knee proprioception is believed to be deficient after anterior cruciate ligament (ACL) injury. Tests of joint position sense (JPS) are commonly used to assess knee proprioception, but their psychometric properties (PMPs) are largely unknown.Purpose: To evaluate the PMPs (reliability, validity, and responsiveness) of existing knee JPS tests targeting individuals with ACL injury.Study design: Systematic review; Level of evidence, 4.Methods: PubMed, Allied and Complementary Medicine, CINAHL, SPORTDiscus, Web of Science, Scopus, CENTRAL, and ProQuest databases were searched to identify studies that assessed PMPs of knee JPS tests in individuals with ACL injury. The risk of bias for each included study was assessed and rated at the outcome level for each knee JPS test. Overall quality and levels of evidence for each PMP were rated according to established criteria. Meta-analyses with mean differences were conducted using random effects models when adequate data were available.Results: Included were 80 studies covering 119 versions of knee JPS tests. Meta-analyses indicated sufficient quality for known-groups and discriminative validity (ACL-injured knees vs knees of asymptomatic controls and contralateral noninjured knees, respectively), owing to significantly greater absolute errors for ACL-injured knees based on a strong level of evidence. A meta-analysis showed insufficient quality for responsiveness, which was attributed to a lack of significant change over time after diverse interventions with a moderate level of evidence. Statistical heterogeneity (I 2 > 40%) was evident in the majority of meta-analyses. All remaining PMPs (reliability, measurement error, criterion validity, convergent validity, and other PMPs related to responsiveness) were assessed qualitatively, and they failed to achieve a sufficient quality rating. This was a result of either the study outcomes not agreeing with the statistical cutoff values/hypotheses or the level of evidence being rated as conflicting/unknown or based on only a single study.Conclusion: Knee JPS tests appear to have sufficient validity in differentiating ACL-injured knees from asymptomatic knees. Further evidence of high methodologic quality is required to ascertain the reliability, responsiveness, and other types of validity assessed here. We recommend investigations that compare the modifiable methodologic components of knee JPS tests on their PMPs to develop standardized evidence-based tests.
|
|
| 7. |
- Jafari, Hedyeh, et al.
(författare)
-
A novel data driven model of ageing postural control
- 2019
-
Konferensbidrag (refereegranskat)abstract
- BackgroundPostural control is a complex system. Based on sensorimotor integration, the central nervous system (CNS) maintains balance by sending suitable motor commands to the muscles. Physiological decline due to ageing, affects balance performance through failing postural control – and in turn affects falls self-efficacy and activity participation. Understanding how the CNS adapts to these changes and predicts the appropriate motor commands to stabilize the body, has been a challenge for postural control research the latest years.AimsTo understand and model the performance of the central nervous system as the controller of the human body.MethodsModelling was based on postural control data from 45 older adults (70 years and older). Ankle, knee and hip joint kinematics were measured during quiet stance using a motion capture system. Principal component analysis was used in order to reduce the measured multidimensional kinematics from a set of correlated discrete time series to a set of principal components. The outcome was utilized to predict the motor commands. The adaptive behaviour of the CNS was modelled by recurrent neural network including the efference copy for rapid predictions. The data from joint kinematics and electromyography (EMG) signals of the lower limb muscles were measured and separated into training and test data sets.ResultsThe model can predict postural motor commands with very high accuracy regardless of a large physiological variability or balancing strategies. This model has three characteristics: a) presents an adaptive scheme to individual variability, 2) showcases the existence of an efference copy, and 3) is human experimental data driven.ConclusionThe model can adapt to physical body characteristics and individual differences in balancing behaviour, while successfully predict motor commands. It should therefore be utilised in the continued pursuit of a better understanding of ageing postural control.
|
|
| 8. |
- Jafari, Hedyeh, et al.
(författare)
-
On Internal Modeling of the Upright Postural Control in Elderly
- 2018
-
Ingår i: IEEE ROBIO 2018. - : IEEE. ; , s. 231-236
-
Konferensbidrag (refereegranskat)abstract
- The second most common cause of injury in the elderly population is falling. In an effort to understand the mechanism behind the reduced ability to maintain balance in any posture or activity, we study the performance of the central nervous system as a controller of the body, while maintaining the balance in some postures or activities. Towards this direction, forty-five subjects aged over 70 were tested in different trials of quiet stance: a) hard stable surface with open eyes, b) stable surface with closed eyes, c) soft unstable surface with open eyes, and d) unstable surface, while eyes were closed. In the sequel, the body kinematics were described by legs and trunk segment angles in the sagittal plane, while the muscle activations were described by a weighted sum of rectified EMG signals from tibialis anterior and gastrocnemius muscles of left and right legs. Using the neuro-science hypothesis and adaptive control theory, a completely novel model was identified for the CNS based on the feedback internal model. The proposed model is able to predict the output commands, based on a recurrent neural network, while the efficiency of the proposed scheme has been proven based on multiple experimental results, showing that the model can sufficiently predict the muscle activity based on the optimum sensory inputs.
|
|
| 9. |
- Mamikoglu, Umut, et al.
(författare)
-
Elbow Joint Angle Estimation by Using Integrated Surface Electromyography
- 2016
-
Ingår i: 24th Mediterranean Conference on Control and Automation (MED). - Piscataway, NJ : IEEE Communications Society. - 9781467383455 ; , s. 785-790
-
Konferensbidrag (refereegranskat)abstract
- Electromyography (EMG) signals represent the electrical activation of skeletal muscles and contain valuable information about muscular activity. Estimation of the joint movements by using surface EMG signals has great importance as a bio-inspired approach for the control of robotic limbs and prosthetics. However interpreting surface EMG measurements is challenging due to the nonlinearity and user dependency of the muscle dynamics. Hence it requires complex computational methods to map the EMG signals and corresponding limb motions. To solve this challenge we here propose to use an integrated EMG signal to identify the EMG-joint angle relation instead of using common EMG processing techniques. Then we estimate the joint angles for elbow flexion-extension movement by using an auto-regressive integrated moving average with exogenous input (ARIMAX) model, which takes integrated EMG measurements as input. The experiments showed that the suggested approach results in a 21.85% average increase in the estimation performance of the elbow joint angle compared to the standard EMG processing and identification.
|
|
| 10. |
- Mamikoglu, Umut, et al.
(författare)
-
Electromyography Based Joint Angle Estimation and Control of a Robotic Leg
- 2016
-
Ingår i: 6th IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob 2016). - Piscataway, NJ : IEEE Communications Society. - 9781467383455 ; , s. 182-187
-
Konferensbidrag (refereegranskat)abstract
- Musculoskeletal modeling based on Electromyography (EMG) has many applications in physiotherapy and biologically-inspired robotics. In this article, a novel methodology for the modeling of the dynamics of an antagonistic muscle pair that actuates the human ankle joint movements will be established. As it will be presented, the musculoskeletal model is based on a multi input single output (MISO) auto-regressive integrated moving average with exogenous input (ARIMAX) model, which takes the integrated EMG measurements as input and estimates the corresponding joint angles. Based on this methodology, a Pneumatic Artificial Muscle (PAM) robotic leg setup that mimics the flexion/extension movement of human ankle joint is controlled to replicate the human movement. The experimental results demonstrate the performance of EMG based joint angle estimation and control of the robotic leg with the proposed model.
|
|
