Effects of the center of mass of a stick vacuum cleaner on the muscle activities of the upper extremity during floor vacuuming.

Cordless stick vacuum cleaners on the market have two distinctive styles. One with the center of mass (CoM) near user's hand and the other with the CoM near the brush. The main objective of this study was to determine whether the CoM would affect the muscle activities of upper extremity during floor vacuuming. Twenty-four participants conducted floor vacuuming strokes on carpeted floor and tiled floor at two different speeds with a 2.57 kg stick cleaner model with the CoM near its handle and near its brush. The 50th %-ile muscle activities ranged from 5.4% to 16.3% of the maximum activity level (mild to moderate intensity), with significantly greater activities (p < 0.05) when vacuuming with the high CoM model. Study results suggest that conventional low CoM stick cleaners are preferable to high CoM stick cleaners to lower physical loads to user's upper extremity muscles for floor vacuuming.