Ergonomic indexes for upper limb musculoskeletal
disorders risk quantification according to manual
wheelchair kinematics

Nicolas Louis, Guillaume Desroches, Raphael Dumas, Philippe Vaslin,
Laurence Cheze, Philippe Gorce

► To cite this version:

Nicolas Louis, Guillaume Desroches, Raphael Dumas, Philippe Vaslin, Laurence Cheze, et al. . Er-gonomic indexes for upper limb musculoskeletal disorders risk quantification according to manual wheelchair kinematics. Rehabilitation: Mobility, Exercise & Sports – 4th International State-of-the-Art Congress, Vrije Universiteit, Amsterdam, Apr 2009, Amsterdam, Netherlands. pp.42-44. hal-04999463

HAL Id: hal-04999463

https://uca.hal.science/hal-04999463v1

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Distributed under a Creative Commons Attribution 4.0 International License
Ergonomic indexes for upper limb
musculoskeletal disorders risk
quantification according to manual
wheelchair kinematics

Nicolas LOUIS<sup>a</sup>, Guillaume DESROCHES<sup>b</sup>, Raphael DUMAS<sup>b</sup>, Philippe VASLIN<sup>c</sup>,
Laurence CHEZE<sup>b</sup> and Philippe GORCE<sup>a,1</sup>

<sup>a</sup>HANDIBIO-EA 4322, Laboratoire de Bio-modélisation et d'ingénierie des Handicaps,
Université du Sud Toulon-Var, La Garde, France

<sup>b</sup>LBMC UMR T 9406, UCBL-INRETS, Université de Lyon, Villeurbanne, France

<sup>c</sup>LIMOS UMR 6158, CNRS Université Blaise Pascal Clermont 2, Aubière, France

**Abstract.** Manual wheelchair propulsion is a well known factor of upper limb musculoskeletal disorders risk (ULMDR). Through a large bibliographic review, movement amplitude and repetition, proximity of joints limits, user overweight and vertical forces are commonly admitted as the main risk factors of upper limb injuries in wheelchair propulsion. Thus, we propose a clinically usable method to quantify ULMDR according to wheelchair kinematics. Through a synthesis of literature information, for the three upper limb joints, ergonomic indexes were grouped in a general equation to quantify ULMDR. A case study has been realized. A 3D analysis of upper limb motion during propulsion was made using a Vicon 460 system. Four different wheelchair configurations were tested: two seat heights and two anterior-posterior wheel positions. For both seat heights, computed ULMDR are less important for backward position. For both antero-posterior wheel positions, computed ULMDR are less important for the highest seat position. The results showed good promises at quantifying the impact of sitting changes on ULMDR. These ergonomic indexes could be helpful in clinical settings when prescribing a wheelchair. To validate this method, a longitudinal study will be performed. Forces applied on hand rims will be added in further development.

**Keywords.** Musculoskeletal disorder, wheelchair, upper limb, kinematics

**Introduction**

Manual wheelchair propulsion is a well known factor of upper limb musculoskeletal disorders risk (ULMDR) [1, 2]. Through a large bibliographic review, movement amplitude and repetition, proximity of joints limits, user overweight and vertical forces are commonly admitted as the main risk factors of upper limb injuries in wheelchair propulsion. Thus, we propose a clinically usable method to quantify ULMDR according to wheelchair kinematics.

¹ Corresponding Author : Philippe GORCE, HANDIBIO-EA 4322, Laboratoire de Bio-modélisation et d'ingénierie des Handicaps, Université du Sud Toulon-Var, La Garde, France ; E-mail :
philippe.gorce@univ-tln.fr
# 1. Ergonomic indexes for ULMDR

Through a synthesis of literature information [2-8], for the three upper limb joints, ergonomic indexes for ULMDR were grouped in a general equation Eq. (1). Equation parameters are depending on the articulation:

* Shoulder flexion-extension and then abduction are the main biomechanical risk factors of shoulder pain.

* Elbow ULMDR is link with the flexion-extension angle.

* Studies reporting on the wrist highlighted the importance of flexion-extension in carpal tunnel syndrome and tendinitis. Eq. (2) defined the wrist ergonomic index for ULMDR.

# 2. Case study: material and method

To illustrate ergonomic indexes for ULMDR, a case study have been realized on one able-bodied subject (age : 41 years old, weight : 71kg, height : 184cm, arm length : 35cm, forearm length : 28cm, hand : 21cm). Four different wheelchair configurations were tested: two seat heights (51cm and 54 cm) and two anterior-posterior wheels positions (1cm and 4cm). 3D analysis of upper extremity motion was made using a Vicon 460 system (Oxford Metrics, Oxford, UK). Fifty anatomical and technical markers were installed on the wheelchair and participant.

Upper body is considered as a rigid segment articulated system (trunk, arm, forearm and hand). For each segment, an anatomical frame is defined according to ISB recommendations [9]. Thus, Euler angles were chosen to describe upper body's relative movements. An inverse kinematic model permits to quantify the successive rotations corresponding to shoulder flexion-extension, shoulder adduction-abduction, shoulder internal-external rotation, elbow flexion-extension, wrist pronation-supination (WP), wrist flexion-extension (WFE) and wrist radio-ulnar deviation (WD). Respective rotation amplitudes have been computed (WPA, WFEA, WDA) for a propulsive cycle. Ergonomic indexes for ULMDR describe in Eq. (1), and for the wrist in particular in Eq. (2), were quantified.

# 3. Results

For both seat heights, computed ULMDR are less important for backward position. For both antero-posterior wheel positions, computed ULMDR are less important for the highest seat position. Figure 1 illustrates those results for the wrist.

# 4. Conclusion

The results showed good promises at quantifying the impact of sitting changes on ULMDR. These ergonomic indexes could be helpful in clinical settings when prescribing a wheelchair. To validate this method, a longitudinal study will be performed. Forces applied on hand rims will be added in further development.
<figure><img src="image_2.png" /><figcaption>Figure 1. Wrist musculoskeletal disorder risk evolution according to propulsion cycle percentage.</figcaption></figure>

$$ULMDR = \alpha(\text{Movement Amplitude}) + \beta(\text{Articular Position}) \quad (1)$$

$$ \text{Wrist ULMDR} = 0.25[0.1(\text{WFEA} > 0.8 * 150) + 0.2(\text{WDA} > 0.8 * 65) + 0.7(\text{WPA} > 0.8 * 165)] + 0.75[0.1(\text{WP} > 0) + 0.2\left(\frac{\left(\tanh\left(\frac{\text{WD}-2.5}{2}-6\right)+1\right)}{2}\right) + 0.7\left(\frac{\left(\tanh\left(\frac{\text{WFEA}}{5}-5\right)+1\right)}{2}\right)] \quad (2) $$

References

[1] S.J. Mulroy, et al., Effects of spinal cord injury level on the activity of shoulder muscles during wheelchair propulsion: an electromyographic study. *Archives of physical medicine and rehabilitation* 85 (2004), 925-934.

[2] H.E. Veeger, L.A. Rozendaal, and F.C. van der Helm, Load on the shoulder in low intensity wheelchair propulsion. *Clinical biomechanics* 17(3) (2002), 211-8.

[3] M.L. Boninger, et al., Shoulder and elbow motion during two speeds of wheelchair propulsion: a description using a local coordinate system. *Spinal Cord* 36(6) (1998), 418-26.

[4] M.L. Boninger, et al., Pushrim biomechanics and injury prevention in spinal cord injury: recommendations based on CULP-SCI investigations. *Journal of Rehabilitation Research & Development* 42(3 Suppl 1) (2005), 9-19.

[5] A.M. Koontz, et al., Shoulder kinematics and kinetics during two speeds of wheelchair propulsion. *Journal of Rehabilitation Research & Development* 39 (2002), 635-649.

[6] P. Mukhopadhyay, L. O'Sullivan, and T.J. Gallwey, Estimating upper limb discomfort level due to intermittent isometric pronation torque with various combinations of elbow angles, forearm rotation angles, force and frequency with upper arm at 90° abduction. *International Journal of Industrial Ergonomics* 37 (2007), 313-325.

[7] I.A. Murray and G.R. Johnson, A study of the external forces and moments at the shoulder and elbow while performing every day tasks. *Clinical biomechanics* 19(6) (2004), 586-94.

[8] S.D. Shimada, et al., Kinematic characterization of wheelchair propulsion. *Journal of Rehabilitation Research & Development* 35(2) (1998), 210-8.

[9] G. Wu, et al., ISB recommendation on definitions of joint coordinate systems of various joints for the reporting of human joint motion--Part II: shoulder, elbow, wrist and hand. *Journal of Biomechanics* 38(5) (2005), 981-992.