The goal of this project will be to develop biomechanical guidelines for optimum, non-stressful shoulder function. Specifically the aims to define the timing, relative intensity and synergies of shoulder muscle action and the shoulder joint motion and forces involved in wheelchair propulsion and body transfer by SCI patients with discriminating levels of complete paraplegia and quadriplegia. Today's increased longevity and mobility of spinal cord injury (SCI) patients has led to disabling shoulder pain becoming a significant clinical problem which appears to be a consequence of overuse. To assess the underlying pathomechanics responsible for the shoulder joint pain, asymptomatic shoulder muscle function and joint mechanics during the primary high demand activities of SCI patients must be documented. Four functional groups of asymptomatic complete SCI patients (lumbar and thoracic paraplegics, low and C6 quadriplegics) and one group of SCI patients with painful shoulders will be tested. Function of the supraspinatus, infraspinatus, subscapularis, anterior, middle, and posterior deltoid, long head of biceps brachii, serratus anterior, latissimus dorsi and pectoralis major will be recorded with dynamic EMG using intramuscular fine wire electrodes and telemetered signal transmission. Motion of the shoulder, elbow and wrist joints will be measured with the Vicon Motion Analysis System. Wheelchair propulsion forces will be recorded with a strain gauge instrumented wheel. With a modified bicycle ergometer the resistance of several locomotor conditions will simulated. These data will be collected simultaneously while the subjects perform body transfers and wheel their chairs at free and fast velocities on a vinyl tile and carpeted floor, on the ergometer set to reproduce the resistance of inclines (2 and 4 degrees) and rough surfaces (carpet and concrete) and around an outdoor concrete track for a 22 minute endurance test. Prior to the functional tests, maximal isometric shoulder elevation in the scapular plane (scaption) and internal and external rotation torques will be measured with a Cybex dynamometer. Shoulder depressor and trunk flexion and extension forces will be recorded with a cable tensiometer. The data will be analyzed to correlate patterns of muscle activity with the joint motions and propulsion forces. Shoulder joint moments and forces will be calculated. The influence of trunk stability and fatigue on shoulder muscle function will be assessed. The relative demands of the different environmental situations will be determined. Statistical significance of the findings will be determined by split-plot ANOVA and regression analyses.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR041018-02
Application #
3161460
Study Section
Orthopedics and Musculoskeletal Study Section (ORTH)
Project Start
1991-07-01
Project End
1994-06-30
Budget Start
1992-07-01
Budget End
1993-06-30
Support Year
2
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Rancho Los Amigos Medical Center
Department
Type
DUNS #
City
Downey
State
CA
Country
United States
Zip Code
90242
Mulroy, Sara J; Farrokhi, Shawn; Newsam, Craig J et al. (2004) Effects of spinal cord injury level on the activity of shoulder muscles during wheelchair propulsion: an electromyographic study. Arch Phys Med Rehabil 85:925-34
Newsam, Craig J; Lee, Audrey D; Mulroy, Sara J et al. (2003) Shoulder EMG during depression raise in men with spinal cord injury: the influence of lesion level. J Spinal Cord Med 26:59-64
Kulig, K; Newsam, C J; Mulroy, S J et al. (2001) The effect of level of spinal cord injury on shoulder joint kinetics during manual wheelchair propulsion. Clin Biomech (Bristol, Avon) 16:744-51
Newsam, C J; Rao, S S; Mulroy, S J et al. (1999) Three dimensional upper extremity motion during manual wheelchair propulsion in men with different levels of spinal cord injury. Gait Posture 10:223-32
Kulig, K; Rao, S S; Mulroy, S J et al. (1998) Shoulder joint kinetics during the push phase of wheelchair propulsion. Clin Orthop Relat Res :132-43
Perry, J; Gronley, J K; Newsam, C J et al. (1996) Electromyographic analysis of the shoulder muscles during depression transfers in subjects with low-level paraplegia. Arch Phys Med Rehabil 77:350-5
Rao, S S; Bontrager, E L; Gronley, J K et al. (1996) Three-dimensional kinematics of wheelchair propulsion. IEEE Trans Rehabil Eng 4:152-60
Mulroy, S J; Gronley, J K; Newsam, C J et al. (1996) Electromyographic activity of shoulder muscles during wheelchair propulsion by paraplegic persons. Arch Phys Med Rehabil 77:187-93
Reyes, M L; Gronley, J K; Newsam, C J et al. (1995) Electromyographic analysis of shoulder muscles of men with low-level paraplegia during a weight relief raise. Arch Phys Med Rehabil 76:433-9
Powers, C M; Newsam, C J; Gronley, J K et al. (1994) Isometric shoulder torque in subjects with spinal cord injury. Arch Phys Med Rehabil 75:761-5