Biomechanic evaluation of upper-extremity symmetry during manual wheelchair propulsion over varied terrain.

College of Medicine, Department of Orthopedic Research, Mayo Clinic, Rochester, MN, USA.
Archives of physical medicine and rehabilitation (Impact Factor: 2.44). 11/2008; 89(10):1996-2002. DOI: 10.1016/j.apmr.2008.03.020
Source: PubMed

ABSTRACT To evaluate upper-extremity symmetry during wheelchair propulsion across multiple terrain surfaces.
Case series.
A biomechanics laboratory and the general community.
Manual wheelchair users (N=12).
Not applicable.
Symmetry indexes for the propulsion moment, total force, tangential force, fractional effective force, time-to-peak propulsion moment, work, length of push cycle, and power during wheelchair propulsion over outdoor and indoor community conditions, and in laboratory conditions.
Upper-extremity asymmetry was present within each condition. There were no differences in the magnitude of asymmetry when comparing laboratory with indoor community conditions. Outdoor community wheelchair propulsion asymmetry was significantly greater than asymmetry measured during laboratory conditions.
Investigators should be aware that manual wheelchair propulsion is an asymmetrical act, which may influence interpretation when data is collected from a single limb or averaged for both limbs. The greater asymmetry identified during outdoor versus laboratory conditions emphasizes the need to evaluate wheelchair biomechanics in the user's natural environment.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of this study was to quantify the effects of five distinct slopes on spatiotemporal and pushrim kinetic measures at the nondominant upper limb during manual wheelchair (MWC) propulsion on a motorized treadmill in individuals with spinal cord injury (SCI). Eighteen participants with SCI propelled their MWC at a self-selected natural speed on a treadmill at different slopes (0, 2.7, 3.6, 4.8, and 7.1 degrees). Spatiotemporal parameters along with total force and tangential components of the force applied to the pushrim, including mechanical effective force, were calculated using an instrumented wheel. The duration of the recovery phase was 54% to 70% faster as the slope increased, whereas the duration of the push phase remained similar. The initial contact angles migrated forward on the pushrim, while the final and total contact angles remained similar as the slope increased. As the slope increased, the mean total force was 93% to 201% higher and the mean tangential component of the force was 96% to 176% higher than propulsion with no slope. Measures were similar for the 2.7 and 3.6 degrees slopes. Overall, the recovery phase became shorter and the forces applied at the pushrim became greater as the slope of the treadmill increased during motorized treadmill MWC propulsion.
    The Journal of Rehabilitation Research and Development 01/2014; 51(5):789-802. DOI:10.1682/JRRD.2013.07.0168 · 1.69 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The main objective was to quantify the effects of five different slopes on trunk and shoulder kinematics as well as shoulder kinetic and muscular demands during manual wheelchair (MWC) propulsion on a motorized treadmill. Eighteen participants with spinal cord injury propelled their MWC at a self-selected constant speed on a motorized treadmill set at different slopes (0°, 2.7°, 3.6°, 4.8°, and 7.1°). Trunk and upper limb movements were recorded with a motion analysis system. Net shoulder joint moments were computed with the forces applied to the handrims measured with an instrumented wheel. To quantify muscular demand, the electromyographic activity (EMG) of the pectoralis major (clavicular and sternal portions) and deltoid (anterior and posterior fibers) was recorded during the experimental tasks and normalized against maximum EMG values obtained during static contractions. Overall, forward trunk flexion and shoulder flexion increased as the slope became steeper, whereas shoulder flexion, adduction, and internal rotation moments along with the muscular demand also increased as the slope became steeper. The results confirm that forward trunk flexion and shoulder flexion movement amplitudes, along with shoulder mechanical and muscular demands, generally increase when the slope of the treadmill increases despite some similarities between the 2.7° to 3.6° and 3.6° to 4.8° slope increments.
    01/2015; 2015:1-15. DOI:10.1155/2015/636319
  • [Show abstract] [Hide abstract]
    ABSTRACT: In sidewalks, slopes for vehicle crossings are often installed, and pedestrians have to walk across these slopes. The present study examined the influences of slope gradients on the danger and physical strain during stroller locomotion. Nine female participants walked forward while pushing a stroller with a dummy baby on a mock sidewalk with 1) a cross slope (the whole surface of the sidewalk tilted sideways) at gradients of 0%, 5%, 10%, and 15%, and 2) combined slopes connecting a cross slope at gradients of 0%, 5%, 10%, and 15% and a flat 0% area. The velocity and tracks of the stroller, the pressure between the palm and the stroller handle, and an electromyogram (EMG) of the upper limbs of the participant were measured during stroller locomotion. Throughout both the cross and the combined slopes, the participants decreased their locomotion velocity according to the increase in the slope gradient. The steeper slope led the stroller to drift off-course to the downhill direction and caused increased pressure between the palm of the participant and the handle and increased EMG values, especially in the forearms. The results indicated that, on a sidewalk with a steeper cross slope, it is difficult for stroller users to maintain their intended course, even if they decrease their locomotion velocity and make their greater physical effort.
    12/2013; 10:43-50. DOI:10.4028/

Full-text (2 Sources)

Available from
Jul 21, 2014