Kinematic and electromyographic analysis of wheelchair propulsion on ramps of different slopes for young men with paraplegia.

ABSTRACT

OBJECTIVE: To gain insight into the biomechanics of upslope wheelchair stroking by examining the changes in kinematic and electromyographic characteristics of wheelchair propulsion over ramps of different slopes. DESIGN: Repeated-measures design. Each subject pushed up a wooden ramp (7.3m long) 3 times at self-selected normal and fast speeds for each of these slopes 0 degrees , 2 degrees , 4 degrees , 6 degrees , 8 degrees , 10 degrees , and 12 degrees . SETTING: A biomechanics laboratory. PARTICIPANTS: Young men (N=10) with paraplegia. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Electromyographic activity of extensor carpi radialis, triceps brachii, antero-middle and postero-middle deltoids, pectoralis major, and latissimus dorsi, and stroking kinematics. RESULTS: Forward lean of the trunk increased as the slope increased. The triceps brachii, antero-middle deltoid, and pectoralis major were more active during the push phase, while the postero-middle deltoid was more active during the recovery phase. Both extensor carpi radialis and latissimus dorsi were active throughout a stroke. Major adjustments in stroking kinematics and significant increases in muscle activity occurred at slopes between 4 degrees and 10 degrees . CONCLUSION: In addition to a decrease in stroking speed, the stroking pattern becomes more compact (decreased push angle and relative recovery time, increased stroke frequency) and the trunk becomes more active with increasing slope.