ORIGINAL
ARTICLE – abstractScapular
muscle fatigue in athletes with shoulder impingement syndrome: an Emg
analysis Shweta
Shenoy, Vikrant Mohan Miglani, Jaspal
Singh Sandhu
Department
of Sports Medicine and Physiotherapy, Guru Nanak Dev University,
Amritsar, State- Punjab, India
Abstract
Background:
Shoulder muscle fatigue is a common sequela of repetitive arm use and
proposed as a possible link to explain the association between
repetitive arm use and development of shoulder pain. Objective: To
identify and compare the fatigue produced in scapular muscles in
injured and non-injured side in athletes with impingement syndrome and
also with athletes without impingement syndrome. Design And
Methodology: Experimental study with different subject design. 20
overhead athletes from various sports participated in this study. 10
athletes had shoulder impingement syndrome and 10 were healthy
athletes. Subjects performed submaximal contraction (40% - 80% of MVIC)
for 30 seconds of four scapular muscles i.e. upper trapezius, middle
trapezius, lower trapezius and serratus anterior. The fatigue was
calculated by measuring the median frequency difference (frequency
shift) between the first 10 seconds (0-10) contraction and last 10
seconds (20-30) contraction. Results: There was significant (p ≤
0.05) increase in frequency shift (25% - 85% more fatigue) in the four
scapular muscles on the injured side of impingement group as compared
to the same side of control group. On comparing injured and non-injured
side of impingement group, injured side showed significant (p ≤
0.05) increase in frequency shift (30% - 90% more fatigue) in the four
muscles. Conclusion: Athletes with shoulder impingement syndrome have
more median frequency shift in UT, MT, LT, & SA muscles on
injured side as compared to non-injured side as well as same side of
control group.
Key
words:impingement,
fatigue, frequency, electromyography
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