Influence of lower leg muscle fatigue on the centre of pressure in a static upright posture.

We examined the influence of fatigue in the lower leg muscles on the centre of pressure sway during a static upright posture. Twelve healthy young men and women completed the exercise stress test on the triceps surae muscle and continued the exercise until their muscles were fatigued. A centre of pressure sway of 1 min was carried out in a Romberg posture at rest and at different instants after fatiguing exercise: immediately after, 5 min after, and 10 min after exercise. Blood lactate concentration was measured from fingertip samples taken before and immediately after exercise. To evaluate body sway, the following four centre of pressure sway factors were selected: unit time sway, front-back sway, left-right sway, and high-frequency band power spectrum. The measurement device used was an Anima stabilometer (G5500). The data sampling frequency was 20 Hz. After exercise, blood lactate concentration was increased. Significant differences were observed in unit time sway, front-back sway, and high-frequency band power spectrum immediately after exercise. These values eventually returned to baseline levels 5 min after fatiguing exercise. [ABSTRACT FROM AUTHOR]