Nicolas Louis

Publications (26) View all

• Article: Wheelchair propulsion kinematics in beginners and expert users: influence of wheelchair settings.

  P Gorce, N Louis
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  ABSTRACT: Biomechanical studies have linked the handrim wheelchair propulsion with a prevalence of upper limb musculoskeletal disorders. The purpose of this study was to examine the influence of the wheelchair settings on upper limb kinematics during wheelchair propulsion. Recordings were made under various wheelchair configuration conditions to understand the effect of wheelchair settings on kinematics parameters such shoulder, elbow and wrist angles. Ten experts and ten beginners' subjects propelled an experimental wheelchair on a roller ergometer system at a comfortable speed. Twelve wheelchair configurations were tested. Kinematics were recorded for each configuration. Based on the hand position relatively to the handrim, the main kinematic parameters of wheelchair propulsion were investigated on the whole propulsion cycle and a key event such as handrim contact and release. Compared to the beginner subjects, all the experts' subjects generally present higher joint amplitude and propulsion speeds. Seat height and antero-posterior axle position influence usage of the hand-rim, timing parameters and configurations of upper limb joints. Results seem to confirm that low and backward seat position allow a greater efficiency. Nevertheless, according that proximity of joint limit is a well known factor of musculoskeletal disorders, our results let us think that too low and backward seat position, increasing joints positions and amplitudes, could increase the risk of upper limb injuries in relation with manual wheelchair propulsion. Kinematic differences highlight that future studies on wheelchair propulsion should only be done with impaired experienced subjects. Furthermore, this study provides indications on how wheelchair settings can be used for upper limb injury prevention.
  Clinical biomechanics (Bristol, Avon) 08/2011; 27(1):7-15. · 1.76 Impact Factor
• Article: Surface electromyography activity of upper limb muscle during wheelchair propulsion: Influence of wheelchair configuration.

  N Louis, P Gorce
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  ABSTRACT: Biomechanical studies have linked handrim wheelchair propulsion with a prevalence of upper limb musculoskeletal disorders. The purpose of this study was to record upper limb muscle recruitment patterns using surface electromyography during wheelchair propulsion. Recordings were made for various wheelchair configurations to understand the effect of wheelchair configuration on muscle recruitment. Ten paraplegic and ten able-bodied subjects propelled a test wheelchair on a roller ergometer system at a comfortable speed. Twelve wheelchair configurations were tested. Upper limb surface electromyography and kinematics were recorded for each configuration. Based on the hand position relative to the handrim, the propulsion cycle was divided into three phases to explain the activation patterns. Compared to the able-bodied subjects, the paraplegic subjects presented higher activation. This is the case for all muscles in the early push phase, for the triceps brachii, pectoralis major and latissimus dorsi in the late push phase and for the trapezius, triceps brachii and latissimus dorsi during recovery. During early push, activation of nearly all muscles was affected by the axle position, where as seat height only affected biceps brachii and pectoralis major activation. During late push, the deltoid anterior was affected by axle position and the biceps brachii by seat height. During recovery, the trapezius was affected by axle position, the deltoid posterior by seat height and the biceps brachii by both. Upper limb muscle recruitment differences highlight that future studies on wheelchair propulsion should only be done with wheelchair experienced paraplegic subjects. Furthermore, this study provides indications on how muscle recruitment is affected by wheelchair configuration.
  Clinical biomechanics (Bristol, Avon) 11/2010; 25(9):879-85. · 1.76 Impact Factor
• Conference Proceeding: Upper limb musculoskeletal disorder prevention : an application to wheelchair prescription and configuration

  N. Louis, P. Gorce
  PREMUS 2010 : Seventh conference on prevention of work-related musculoskeletal disordersPREMUS 2010 : Seventh conference on prevention of work-related musculoskeletal disorders, Angers, France; 01/2010
• Article: Upper limb muscle forces during a simple reach-to-grasp movement: a comparative study.

  N Louis, P Gorce
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  ABSTRACT: Muscle force knowledge during reaching is an important research field and tools development for measuring those forces is a challenging task, especially for clinical routines. The purpose of this study was, during a simple reach-to-grasp movement, to compare forces estimation from a Hill-type model and from the EMG-to-Force Processing (EFP) method. Ten healthy male volunteers were tested. Surface EMG signals were recorded from deltoid scapular, deltoid clavicular, triceps brachii, and biceps brachii. Ten repeated measures of right upper limb kinematics had been recorded. Three reaching distances were tested: 20, 30, and 40 cm. Muscle activations were calculated and forces were estimated by the two methods. Correlations and low RMS error found between the two methods indicate that EFP is a good way to estimate muscle forces for this kind of movement. This knowledge is essential in order to integrate these forces in reaching models developed nowadays in robotic, rehabilitation, and ergonomics field of research.
  Medical & Biological Engineering 09/2009; 47(11):1173-9. · 1.76 Impact Factor
• Article: Comments about the article titled: Validation of a musculoskeletal model of wheelchair propulsion and its application to minimizing shoulder joint forces, written by S.R. Dubowsky, J. Rasmussen, S.A. Sisto, N.A. Langrana (41(2008) 2981-2988).

  Nicolas Louis
  Journal of biomechanics 08/2009; 42(15):2627. · 2.66 Impact Factor