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Electromyographic
(EMG) activity of the lumbar extensor muscles: Effect of angle and
hand position during Roman chair exercise.
Mayer JM, Verna JL, Pierra EA, Robertson VL, Graves JE. Arch Phys
Med Rehabil, 1999;80:751-5.
Objective: The purpose of this study was to evaluate the effects
of angle and hand position during variable angle Roman chair (VARC)
back extension exercise on lumbar paraspinal electromyographic (EMG)
activity.
Design: Descriptive, repeated measures.
Setting: University-based musculoskeletal research laboratory.
Participants: 2 female and 8 male volunteers recruited from
a university setting.
Intervention, outcome measures: Surface integrated EMG activity was
recorded from the L3-L4 paraspinal region during 24 ten 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/repetition
was used for analysis.
Results: Significant lumbar paraspinal EMG activity was evident
during each of the 24 repetitions (p < 0.05), 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.
Conclusion: Lumbar paraspinal EMG activity can be altered during
VARC back extension exercise by changing angle and hand position.
Clinicians can use this data to develop progressive resistance exercise
programs utilizing the VARC apparatus.
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