engleski

Effects of vertical center of mass redistribution on body sway parameters during quiet standing

Body sway is usually described by the center of foot pressure (COP)–derived parameters. Their sensitivity to the vertical center of mass (COM) redistribution below its natural position has not yet been examined. Here we examined the effects of both lowering and raising the COM on the following body sway parameters: cumulative, medial-lateral and anterior-posterior COP average velocity, amplitude and frequency. For this purpose, 13 healthy male subjects performed a quiet stance balance task with feet positioned parallel in the hip width (PS) and with hands holding a stick on the rear part of the shoulders. Each subject carried out five different modifications of the PS in a randomized order: no additional load, an additional load of 10 kg and 30 kg suspended from the waist in the mid-lower leg height, and an additional load of 10 kg and 30 kg on a rear part of the shoulders. The studied body sway parameters proved to be sensitive to manipulations used. Specifically, lowering and raising the COM was mirrored in a systematic decrease/increase of the velocity, amplitude, and frequency parameters, indicating more effect in anterior-posterior direction. These results suggest that the elevation of the body COM from low to high position systematically decreases the postural control during quiet standing, and, consequently, increases the intensity of the balancing task. Thus, this type of physical manipulation could ensure a simple progression in functional resistance training for persons with compromised balance.

balance ; body sway ; center of foot pressure ; body mass redistribution

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