Author:
Fujita Mako,Kamibayashi Kiyotaka,Horiuchi Masahiro,Ebine Naoyuki,Fukuoka Yoshiyuki
Abstract
AbstractThe use of body weight support (BWS) can reveal important insights into the relationship between lower-limb muscle activities and the ventilatory response during sinusoidal walking. Here, healthy participants (n = 15) walked on a treadmill while 0%, 30%, and 50% of their body weight was supported with BWS. The walking speed was varied sinusoidally between 3 and 6 km h−1, and three different frequencies, and periods ranging from 2 to 10 min were used. Breath-by-breath ventilation ($${\dot{\text{V}}}_{{\text{E}}}$$
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) and CO2 output ($${\dot{\text{V}}}\text{CO}_{{2}}$$
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) were measured. The tibialis anterior (TA) muscle activity was measured by electromyography throughout the walking. The amplitude (Amp), normalized Amp [Amp ratio (%)], and phase shift (PS) of the sinusoidal variations in measurement variables were calculated using a Fourier analysis. The results revealed that the Amp ratio in $${\dot{\text{V}}}_{{\text{E}}}$$
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increased with the increase in BWS. A steeper slope of the $${\dot{\text{V}}}_{{\text{E}}}$$
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–$${\dot{\text{V}}}\text{CO}_{{2}}$$
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relationship and greater $${\dot{\text{V}}}_{{\text{E}}}$$
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/$${\dot{\text{V}}}\text{CO}_{{2}}$$
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values were observed under reduced body weight conditions. The Amp ratio in TA muscle was significantly positively associated with the Amp ratio in the $${\dot{\text{V}}}_{{\text{E}}}$$
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(p < 0.001). These findings indicate that the greater amplitude in the TA muscle under BWS may have been a potent stimulus for the greater response of ventilation during sinusoidal walking.
Funder
Japan Society for the Promotion of Science
Publisher
Springer Science and Business Media LLC