Effects of eccentric exercise on trapezius electromyography during computer work with active and passive pauses

The aim of this laboratory study was to investigate the effects of eccentric exercises on the trapezius muscle spatial electromyographic (EMG) activity during computer work with active and passive pauses.

Twelve healthy male subjects performed computer work with passive (relax) and active (30% maximum voluntary contraction of shoulder elevation) pauses given every 40s over 2 days, before, immediately and 24h after eccentric exercise. Surface EMG signals were recorded from four parts of the trapezius during computer work.

EMG amplitude during computer work decreased immediately after exercise (P<0.05). In the clavicular and descending parts of the trapezius, the centroid of exposure variation analysis along the time axis was lower during computer work with active pauses compared with passive ones (P<0.05). Further, lower values of relative rest time was observed during active pause (P<0.05).

Eccentric exercises had a short term effect on muscle activation pattern during computer work, and decreased the muscle activity immediately after the exercises. The results of this study showed a more variable trapezius activity pattern and a lower trapezius rest with active pauses compared with passive pauses. Moreover, eccentric exercises resulted in a less variable activation pattern, decreasing the effect of active pauses.