The effect of level of spinal cord injury on shoulder joint kinetics during manual wheelchair propulsion.
OBJECTIVE
The effects of spinal cord injury level on shoulder kinetics during manual wheelchair propulsion were studied.


METHODS
Single session data collection in a laboratory environment.


METHODS
Male subjects were divided into four groups: low level paraplegia (n=17), high level paraplegia (n=19), C7 tetraplegia (C7, n=16) and C6 tetraplegia (C6, n=17). Measurements were recorded using a six-camera VICON motion analysis system, a strain gauge instrumented wheel, and wheelchair ergometer. Shoulder joint forces and moments were calculated using the inverse dynamics approach.


RESULTS
Mean self-selected propulsion velocity was higher in the paraplegic (low paraplegia=90.7 m/min; high paraplegia=83.4 m/min) than tetraplegic (C7=66.5 m/min; C6=47.0 m/min) groups. After covarying for velocity, no significant differences in shoulder joint moments were identified. However, superior push force in subjects with tetraplegia (C7=21.4 N; C6=9.3 N) was significantly higher than in those with high paraplegia (7.3 N), after covarying velocity.


CONCLUSIONS
The superior push force in the tetraplegic groups coupled with weakness of thoraco-humeral depressors increases susceptibility of the subacromial structures to compression.


CONCLUSIONS
Increased vertical force at the shoulder joint, coupled with reduced shoulder depressor strength, may contribute to shoulder problems in subjects with tetraplegia. Wheelchair design modifications, combined with strength and endurance retention, should be considered to prevent shoulder pain development.
Kulig
K
K
Pathokinesiology Laboratory, Rancho Los Amigos National Rehabilitation Center, 7601 E. Imperial Hwy., Downey, CA 90242, USA. kulig@usc.edu
Newsam
C J
CJ
Mulroy
S J
SJ
Rao
S
S
Gronley
J K
JK
Bontrager
E L
EL
Perry
J
J
D000328:Adult; D000704:Analysis of Variance; D001132:Arm / Q000502:physiology; D001696:Biomechanical Phenomena; D016552:Ergometry; D006801:Humans; D008297:Male; D010264:Paraplegia / Q000503:physiopathology*; D005082:Physical Exertion / Q000502:physiology; D011782:Quadriplegia / Q000503:physiopathology*; D012785:Shoulder Joint / Q000502:physiology*; D019415:Torque; D014910:Wheelchairs