Electromyographic activity of the lumbar extensor muscles: effect of angle and hand position during Roman chair exercise.
OBJECTIVE
To evaluate the effects of angle and hand position during variable-angle Roman chair (VARC) back extension exercise on lumbar paraspinal electromyographic (EMG) activity.


METHODS
Descriptive, repeated measures.


METHODS
University-based musculoskeletal research laboratory.


METHODS
Two female and eight male volunteers recruited from a university setting.


METHODS
Surface integrated EMG activity was recorded from the L3-L4 paraspinal region during 24 10-second repetitions of dynamic back extension exercise, each consisting of a unique VARC angle (six total) and subject hand position (four total). Lumbar paraspinal surface integrated EMG activity measured in millivolts per repetition was used for analysis.


RESULTS
Significant lumbar paraspinal EMG activity was evident during each of the 24 repetitions (p < or = .05), with a 104% increase in activity noted between the lowest and highest. EMG activity increased progressively among hand positions and as the VARC angle became more horizontal. VARC angle affected EMG activity more than hand position, but the greatest impact on EMG activity was produced by modifying both angle and hand position.


CONCLUSIONS
Lumbar paraspinal EMG activity can be altered during VARC back extension exercise by changing angle and hand position. Clinicians can use these data to develop progressive resistance exercise programs using the VARC apparatus.
Mayer
J M
JM
Department of Exercise Science, Syracuse University, NY 13244, USA.
Graves
J E
JE
Robertson
V L
VL
Pierra
E A
EA
Verna
J L
JL
Ploutz-Snyder
L L
LL
D000328:Adult; D001696:Biomechanical Phenomena; D004576:Electromyography; D004867:Equipment Design; D005081:Exercise Therapy / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D006225:Hand / Q000502:physiology*; D006801:Humans; D017116:Low Back Pain / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D008161:Lumbosacral Region; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D010807:Physical Endurance; D011187:Posture; D016059:Range of Motion, Articular; D019415:Torque; D016474:Weight-Bearing