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  • 1
    Language: English
    In: Scientific reports, 2019-12-18, Vol.9 (1), p.19357-11
    Description: The relationship between posture, muscle length properties and performance remains unclear, because of a lack of quantitative data. Studies on grasping tasks suggested that wrist position could favour the extrinsic finger flexor in regards to their length to maximise grip force performance. The present study aimed at providing quantitative evidence of the links between wrist posture, muscle capacities and grip capabilities. It combines experimental measurements and a musculoskeletal model including the force-length relationship of the four prime muscles used in grasping. Participants exerted their maximum grip force on a cylindrical dynamometer in four different wrist postures, including one freely chosen by participants (spontaneous). A musculoskeletal model computed the muscle force level and length from motion capture and muscle activation. Results revealed that participants exerted maximum grip force spontaneously, with a loss of force when using other postures. At muscle force and length level, grip force variation seems to be associated with all the muscles under study. This observation led to a first quantitative link between power grip, posture and muscle properties, which could provide more insight into neuromechanical interaction involved when grasping. The design of ergonomic devices could also benefit from this quantification of the relationship between wrist angle and muscle length properties.
    Subject(s): Biomechanical Phenomena ; Biomechanics ; Electrodes ; Engineering Sciences ; Female ; Force ; Hand Strength - physiology ; Humans ; Male ; Mechanics ; Models, Biological ; Multidisciplinary Sciences ; Muscle, Skeletal - physiology ; Muscles ; Posture ; Regression Analysis ; Science & Technology ; Science & Technology - Other Topics ; Wrist ; Wrist - physiology ; Wrist Joint - physiology ; Young Adult
    ISSN: 2045-2322
    E-ISSN: 2045-2322
    Source: Nature Open Access
    Source: Academic Search Ultimate
    Source: Web of Science - Science Citation Index Expanded - 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
    Source: PubMed Central
    Source: Web of Science - Social Sciences Citation Index – 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
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  • 2
    Language: English
    In: Annals of biomedical engineering, 2017-10-02, Vol.46 (1), p.71-85
    Description: Hand musculoskeletal models provide a valuable insight into the loads withstood by the upper limb; however, their development remains challenging because there are few datasets describing both the musculoskeletal geometry and muscle morphology from the elbow to the finger tips. Clinical imaging, optical motion capture and microscopy were used to create a dataset from a single specimen. Subsequently, a musculoskeletal model of the wrist was developed based on these data to estimate muscle tensions and to demonstrate the potential of the provided parameters. Tendon excursions and moment arms predicted by this model were in agreement with previously reported experimental data. When simulating a flexion–extension motion, muscle forces reached 90 N among extensors and a co-contraction of flexors, amounting to 62.6 N, was estimated by the model. Two alternative musculoskeletal models were also created based on anatomical data available in the literature to illustrate the effect of combining incomplete datasets. Compared to the initial model, the intensities and load sharing of the muscles estimated by the two alternative models differed by up to 180% for a single muscle. This confirms the importance of using a single source of anatomical data when developing such models.
    Subject(s): Article ; Biochemistry ; Biochemistry, general ; Biological and Medical Physics ; Biological and Medical Physics, Biophysics ; Biomechanics ; Biomedical and Life Sciences ; Biomedical Engineering ; Biomedical Engineering and Bioengineering ; Biomedicine ; Biomedicine, general ; Biophysics ; Classical Mechanics ; Clinical imaging ; Digitization ; general ; Hand - physiology ; Human health and pathology ; Humans ; Instantaneous helical axes ; Life Sciences ; Male ; Mechanics ; Middle Aged ; Models ; Models, Biological ; Moment arms ; Motion capture ; Muscle force ; Muscle, Skeletal - physiology ; Physics ; Sarcomere length ; Tendon excursions ; Tissues and Organs ; Wrist - physiology
    ISSN: 0090-6964
    E-ISSN: 1573-9686
    Source: Alma/SFX Local Collection
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  • 3
    Language: English
    In: Medicine and science in sports and exercise, 2012, Vol.44 (10), p.1906-1916
    Description: The aim of this study was to estimate muscle and joint forces during a power grip task. Considering the actual lack of quantification of such internal variables, this information would be essential for sports sciences, medicine, and ergonomics. This study also contributed to the advancement of scientific knowledge concerning hand control during power grip. A specially designed apparatus combining both an instrumented handle and a pressure map was used to record the forces at the hand/handle interface during maximal exertions. Data were processed such that the forces exerted on 25 hand anatomical areas were determined. Joint angles of the five fingers and the wrist were also computed from synchronized kinematic measurements. These processed data were used as input of a hand/wrist biomechanical model, which includes 23 degrees of freedom and 42 muscles to estimate muscle and joint forces. Greater forces were applied on the distal phalanges of the long fingers compared with the middle and the proximal ones. Concomitantly, high solicitations were observed for FDP muscles. A large cocontraction level of extensor muscles was also estimated by the model and confirmed previously reported activities and injuries of extensor muscles related to the power grip. Quantifying hand internal loadings also resulted in new insights into the thumb and the wrist biomechanics. Output muscle tension ratios were all in smaller ranges than the ones reported in the literature. Including wrist and finger interactions in this hand model provided new quantification of muscle load sharing, cocontraction level, and biomechanics of the hand. Such information could complete future investigations concerning handle ergonomics or pathomechanisms of hand musculoskeletal disorders.
    Subject(s): Adult ; Biological and medical sciences ; Ergonomics ; Forearm - physiology ; Fundamental and applied biological sciences. Psychology ; Grip strength ; Hand ; Hand - physiology ; Hand Strength - physiology ; Humans ; Life Sciences ; Male ; Measurement ; Models ; Muscle contraction ; Muscle Strength ; Muscle Strength Dynamometer ; Muscle Tonus - physiology ; Research ; Space life sciences ; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports ; Young Adult
    ISSN: 0195-9131
    E-ISSN: 1530-0315
    Source: Hellenic Academic Libraries Link
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  • 4
    Language: English
    In: Medical & biological engineering & computing, 2017-06-19, Vol.55 (12), p.2227-2244
    Description: Because the force-generating capacities of muscles are currently estimated using anatomical data obtained from cadaver specimens, hand musculoskeletal models provide only a limited representation of the specific features of individual subjects. A scaling method is proposed to individualise muscle capacities using dynamometric measurements and electromyography. For each subject, a strength profile was first defined by measuring net moments during eight maximum isometric contractions about the wrist and metacarpophalangeal joints. The capacities of the five muscle groups were then determined by adjusting several parameters of an initial musculoskeletal model using an optimisation procedure which minimised the differences between measured moments and model estimates. Sixteen volunteers, including three particular participants (one climber, one boxer and one arthritic patient), were recruited. Compared with the initial literature-based model, the estimated subject-specific capacities were on average five times higher for the wrist muscles and twice as high for the finger muscles. The adjustments for particular subjects were consistent with their expected specific characteristics, e.g. high finger flexor capacities for the climber. Using the subject-specific capacities, the model estimates were markedly modified. The proposed protocol and scaling procedure can capture the specific characteristics of the participants and improved the representation of their capacities in the musculoskeletal model.
    Subject(s): Adult ; Analysis ; Biological models ; Biomedical and Life Sciences ; Biomedical Engineering ; Biomedical Engineering and Bioengineering ; Biomedicine ; Computer Applications ; Hand ; Hand - physiology ; Human Physiology ; Humans ; Imaging ; Imaging / Radiology ; Isometric contraction ; Isometric Contraction - physiology ; Life Sciences ; Male ; Measurement ; Methods ; Models ; Models, Biological ; Muscle strength ; Muscle, Skeletal - physiology ; Musculoskeletal system ; Original Article ; Orthopedic surgery ; Radiology ; Resveratrol ; Wrist - physiology ; Young Adult
    ISSN: 0140-0118
    E-ISSN: 1741-0444
    Source: Business Source Ultimate
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
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  • 5
    Language: English
    In: European journal of applied physiology, 2014-12-17, Vol.115 (5), p.947-957
    Description: Purpose This study investigated the hand and wrist muscle capacities among expert rock climbers and compared them with those of non-climbers. The objective was to identify the adaptations resulting from several years of climbing practice. Methods Twelve climbers (nine males and three females) and 13 non-climber males participated in this study. Each subject performed a set of maximal voluntary contractions about the wrist and the metacarpo-phalengeal joints during which net joint moments and electromyographic activities were recorded. From this data set, the muscle capacities of the five main muscle groups of the hand (wrist flexors, wrist extensors, finger flexors, finger extensors and intrinsic muscles) were estimated using a biomechanical model. This process consisted in adjusting the physiological cross-sectional area (PCSA) and the maximal muscle stress value from an initial generic model. Results Results obtained from the model provided several new pieces of information compared to the analysis of only the net joint moments. Particularly, the capacities of the climbers were 37.1 % higher for finger flexors compared to non-climbers and were similar for finger extensor and for the other muscle groups. Climbers thus presented a greater imbalance between flexor and extensor capacities which suggests a potential risk of pathologies. Conclusions The practice of climbing not only increased the strength of climbers but also resulted in specific adaptations among hand muscles. The proposed method and the obtained data could be re-used to optimize the training programs as well as the rehabilitation processes following hand pathologies.
    Subject(s): Adolescent ; Adult ; Biomechanics ; Biomedical and Life Sciences ; Biomedicine ; Electromyography ; Engineering Sciences ; Female ; Fingers - physiology ; Hand - physiology ; Hand modeling ; Hand Strength - physiology ; Human health and pathology ; Human Physiology ; Humans ; Life Sciences ; Male ; Mechanics ; Mountaineering - physiology ; Muscle capacities ; Muscle Strength - physiology ; Muscle, Skeletal - physiology ; Occupational Medicine/Industrial Medicine ; Original Article ; Physical Endurance - physiology ; Sport climbing ; Sports Medicine ; Tissues and Organs ; Training ; Wrist - physiology ; Young Adult
    ISSN: 1439-6319
    E-ISSN: 1439-6327
    Source: Alma/SFX Local Collection
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  • 6
    Language: English
    In: Journal of applied biomechanics, 2015-12, Vol.31 (6), p.430-438
    Description: The objectives of this study were to investigate the effect of handle shape on the grip force distribution in the hand and on the muscle forces during maximal power grip tasks. Eleven subjects maximally grasped 3 handles with different external shapes (circular, elliptic, and double-frustum). A handle dynamometer, equipped with both a force sensor and a pressure map, was used to record the forces exerted at the hand/handle interface. The finger and wrist joint postures were also computed from synchronized kinematic measurement. These processed data were then used as input of a biomechanical hand model to estimate muscle forces. The results showed that handle shape influences the maximal grip force, the grip force distribution, and the finger joint postures. Particularly, we observed that the elliptical shape resulted in a 6.6% lower maximal grip force compared with the circular and double-frustum handle. Concomitantly, the estimated muscle forces also varied significantly according to the handle shape, with up to 48% differences for the flexor digitorum superficialis muscle for example. Interestingly, different muscle coordination strategies were observed depending on the handle shape, therefore suggesting a potential influence of these geometrical characteristics on pathological risks such as tendonitis.
    Subject(s): Adult ; Biotechnology ; Cognitive science ; Ergonomics - instrumentation ; Ergonomics - methods ; Hand Strength - physiology ; Humans ; Life Sciences ; Male ; Man-Machine Systems ; Muscle Contraction - physiology ; Muscle Strength Dynamometer ; Neuroscience ; Pressure ; Reproducibility of Results ; Sensitivity and Specificity ; Stress, Mechanical ; Task Performance and Analysis
    ISSN: 1065-8483
    E-ISSN: 1543-2688
    Source: SPORTDiscus with Full Text
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  • 7
    Language: English
    In: Sports biomechanics, 2017-10-02, Vol.16 (4), p.434-451
    Description: Previous studies suggested that a pronounced weakness of the extensor muscles relative to the flexor muscles could increase the risk of occurrence of lateral epicondylalgia. This study investigates this hypothesis by estimating the ratio of extensor to flexor muscle capacities among healthy non-players (n = 10), healthy tennis players (n = 20), symptomatic players (n = 6), and players who have recovered from lateral epicondylalgia (n = 6). Maximum net joint moments in flexion or extension were measured during seven tasks involving the voluntary contraction of wrist and fingers. Using these data, the muscle capacities of the main muscle groups of the hand (wrist flexors, wrist extensors, finger flexors, finger extensors, and intrinsic muscles) were estimated using a musculoskeletal model. These capacities were then used to compute the extensor/flexor capacity ratios about the wrist and the finger joints. Compared to healthy non-players, healthy players presented higher extensor muscle capacities and greater capacity ratios showing that playing tennis generates specific adaptations of muscle capacities. Interestingly, symptomatic players, similar to those of non-players, showed more imbalanced ratios than healthy players. These results confirm that the ratio of extensor/flexor muscle capacities seems to be associated with lateral epicondylalgia and can be further used to understand its incidence and consequences.
    Subject(s): elbow tendinosis ; Hand ; Life Sciences ; muscle capacity ; musculoskeletal modelling ; net joint moments
    ISSN: 1476-3141
    E-ISSN: 1752-6116
    Source: SPORTDiscus with Full Text
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  • 8
    Language: English
    In: Medical & biological engineering & computing, 2020-08-17, Vol.58 (10), p.2531-2549
    Description: The wrist and finger extensors play a crucial role in the muscle coordination during grasping tasks. Nevertheless, few data are available regarding their force-generating capacities. The objective of this study was to provide a model of the force-length-activation relationships of the hand extensors using non-invasive methods. The extensor carpi radialis (ECR) and the extensor digitorum communis (EDC) were studied as representative of wrist and finger extensors. Ten participants performed isometric extension force-varying contractions in different postures on an ergometer recording resultant moment. The joint angle, the myotendinous junction displacement and activation were synchronously tracked using motion capture, ultrasound and electromyography. Muscle force was estimated via a musculoskeletal model using the measured joint angle and moment. The force-length-activation relationship was then obtained by fitting a force-length model at different activation levels to the measured data. The obtained relationships agreed with previously reported data regarding muscle architecture, sarcomere length and activation-dependent shift of optimal length. Muscle forces estimated from kinematics and electromyography using the force-length-activation relationships were comparable, below 15% differences, to those estimated from moment via the musculoskeletal model. The obtained quantitative data provides a new insight into the different muscle mechanics of finger and wrist extensors. Graphical abstract By combining in vivo data (kinematics, dynamometry, electromyography, ultrasonography) during isometric force-varying contractions with musculoskeletal modelling, the force-length-activation relationships of both finger and wrist extensors were obtained. The results provided a new insight into the role of hand extensors in the generation and control of hand movements.
    Subject(s): Biomechanics ; Biomedical and Life Sciences ; Biomedical Engineering and Bioengineering ; Biomedicine ; Computer Applications ; Engineering Sciences ; Human Physiology ; Imaging ; Mechanics ; Original Article ; Radiology
    ISSN: 0140-0118
    E-ISSN: 1741-0444
    Source: Business Source Ultimate
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
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  • 9
    Language: English
    In: Medicine and science in sports and exercise, 2018-11, Vol.50 (11), p.2311-2321
    Description: INTRODUCTIONBecause the hand joints possess a broad range of motion, the muscle length can vary importantly which might result in significant variations of the muscle force-generating capacities. However, facing the complexity of this musculoskeletal system, no study has examined the effect of hand muscle length change on muscle force. This study aimed to characterize the force–length relationship of muscles involved in wrist and metacarpophalangeal flexion. METHODSEleven participants performed two sessions(i) one for the wrist flexor muscles and (ii) one for the finger flexor muscles. For each session, the participants performed two maximal voluntary contractions and then two progressive isometric ramps from 0% to 100% of their maximal force capacity at five different wrist/metacarpophalangeal angles. Torque, kinematic, and electromyographic data were recorded. An ultrasound scanner was used to measure the myotendinous junction displacement of flexor carpi radialis (FCR) and flexor digitorum superficialis (FDS) during isometric contractions. A three-dimensional relationship between muscle length, force, and activation level was modeled using optimization procedure. RESULTSGlobally, the FCR was stronger and shorter compared with FDS. The results showed that the three-dimensional relationships fitted well the experimental data (mean R = 0.92 ± 0.07 and 0.87 ± 0.11 for FCR and FDS, respectively). Using joint angle and EMG data, this approach allows to estimate the muscle force with low estimation errors (〈9% of Fmax). CONCLUSIONSThis study proposes a new method to investigate the force–length relationship by combining ultrasound measurement, musculoskeletal modeling and optimization procedures. The data and relationships provide a new insight into hand biomechanics and muscle function that could be useful for designing hand tools or surgical operations.
    Subject(s): Adult ; Biomechanical Phenomena ; Biomechanics ; Electromyography ; Engineering Sciences ; Fingers - diagnostic imaging ; Fingers - physiology ; Health aspects ; Humans ; Isometric Contraction ; Male ; Mechanics ; Metacarpophalangeal Joint - diagnostic imaging ; Metacarpophalangeal Joint - physiology ; Muscle Contraction ; Muscle, Skeletal - anatomy & histology ; Muscle, Skeletal - diagnostic imaging ; Muscle, Skeletal - physiology ; Musculoskeletal system ; Range of Motion, Articular ; Research ; Torque ; Ultrasound imaging ; Usage ; Wrist - diagnostic imaging ; Wrist - physiology ; Young Adult
    ISSN: 0195-9131
    E-ISSN: 1530-0315
    Source: Hellenic Academic Libraries Link
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  • 10
    Language: English
    In: International biomechanics, 2016-01-01, Vol.3 (1), p.40-49
    Description: A musculoskeletal model of the hand and wrist can provide valuable biomechanical and neurophysiological insights, relevant for clinicians and ergonomists. Currently, no consistent data-set exists comprising the full anatomy of these upper extremity parts. The aim of this study was to collect a complete anatomical data-set of the hand and wrist, including the intrinsic and extrinsic muscles. One right lower arm, taken from a fresh frozen female specimen, was studied. Geometrical data for muscles and joints were digitized using a 3D optical tracking system. For each muscle, optimal fiber length and physiological cross-sectional area were assessed based on muscle belly mass, fiber length, and sarcomere length. A brief description of model, in which these data were imported as input, is also provided. Anatomical data including muscle morphology and joint axes (48 muscles and 24 joints) and mechanical representations of the hand are presented. After incorporating anatomical data in the presented model, a good consistency was found between outcomes of the model and the previous experimental studies.
    Subject(s): Biomechanics ; extensor mechanism ; extrinsic muscles ; Human health and pathology ; intrinsic muscles ; Life Sciences ; Mechanics ; Musculoskeletal modeling ; Physics ; Tissues and Organs
    ISSN: 2333-5432
    E-ISSN: 2333-5432
    Source: Taylor & Francis Open Access
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