Significant fatigue effect seen in muscle twitch force after five hours of standing work
THURSDAY, July 16, 2015 (HealthDay News) — Standing work is associated with increased muscle fatigue, according to a study published online June 5 in Human Factors.
Maria-Gabriela Garcia, from ETH Zürich, and colleagues determined long-term fatigue effects in the lower limbs associated with standing work. Muscle fatigue was quantified by electrically-induced muscle twitches (muscle twitch force [MTF]), postural stability, and subjective discomfort evaluation in 14 men and 12 women from two different age groups. The participants simulated standing work for a five-hour period, including five-minute seated rest breaks and a 30-minute lunch.
The researchers found that after standing work, MTF showed a significant fatigue effect that persisted beyond 30 minutes after the end of the workday. MTF was not affected on a control day, conducted in the younger age group. After standing work and on the control day there was a significant increase in the center of pressure displacement speed. Immediately after the end of standing work, subjective evaluation of discomfort indicated a significant increase in perception of fatigue; 30 minutes after the end of work this perception did not persist. Neither age nor gender influenced fatigue.
“Long-term fatigue after prolonged standing work may be present without being perceived,” Garcia said in a statement. “Current work schedules for standing work may not be adequate for preventing fatigue accumulation, and this long-lasting muscle fatigue may contribute to musculoskeletal disorders and back pain.”