The most effective exercise for strengthening the supraspinatus muscle: evaluation by magnetic resonance imaging.
BACKGROUND
Electromyography has been used to determine the best exercise for strengthening the supraspinatus muscle, but conflicting results have been reported. Magnetic resonance imaging T2 relaxation time appears to be more accurate in determining muscle activation.


OBJECTIVE
To determine the best exercises for strengthening the supraspinatus muscle.


METHODS
Criterion standard.


METHODS
Six male volunteers performed three exercises: the empty can, the full can, and horizontal abduction. Immediately before and after each exercise, magnetic resonance imaging examinations were performed and changes in relaxation time for the subscapularis, supraspinatus, infraspinatus, teres minor, and deltoid muscles were recorded.


RESULTS
The supraspinatus muscle had the greatest change among the studied muscles in relaxation time for the empty can (10.5 ms) and full can (10.5 ms) exercises. After the horizontal abduction exercise the change in relaxation time for the supraspinatus muscle (3.6 ms) was significantly smaller than that for the posterior deltoid muscle (11.5 ms) and not significantly different from that of the other muscles studied.


CONCLUSIONS
The empty can and full can exercises were most effective in activating the supraspinatus muscle.
Takeda
Yoshitsugu
Y
Department of Orthopaedic Surgery, Tokushima Red Cross Hospital, 28-1 Shinbiraki, Chuden-cho, Komatsushima City, Tokushima 773-8502, Japan.
Kashiwaguchi
Shinji
S
Endo
Kenji
K
Matsuura
Tetsuya
T
Sasa
Takahiro
T
D000328:Adult; D005081:Exercise Therapy / Q000379:methods*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009126:Muscle Relaxation / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D012016:Reference Values; D017006:Rotator Cuff / Q000502:physiology; D012782:Shoulder / Q000502:physiology*; D014891:Weight Lifting / Q000502:physiology