Investigation of Upper Limb and Lower Back Muscle Activity: Experimental of Repetitive Task

The paper focused on the effects occurs on upper limb and lower back muscle while performing a repetitive task in the near and far boundary work area during prolonged sitting. Ten healthy subjects (5 females and 5 males) participated in this study. The surface electromyography (EMG) was recorded for levator scapulae, upper trapezius, anterior deltoid and erector spinae (all in right and left side) which are known as the weakened and tightened muscles due to Musculoskeletal Disorders (MSD). The results of the study showed that the muscles activities of all muscles showed significant increases during prolonged sitting. Subjective discomfort ratings showed prolonged sitting causes slight discomfort in the lower back, upper back and hips. All the muscles activities also showed significant increase from near boundary to far boundary work area (p<0.05). Thus, these findings should be taken into consideration for industries in designing toward safety and comfortable work place in sitting posture.