Running on a lower-body positive pressure treadmill: VO2max, respiratory response, and vertical ground reaction force.
OBJECTIVE
This study investigated maximal oxygen consumption (VO2max) and time to exhaustion while running on a lower-body positive pressure treadmill (LBPPT) at normal body weight (BW) as well as how BW support affects respiratory responses, ground reaction forces, and stride characteristics.


METHODS
Twelve runners performed VO2max tests on a regular treadmill and an LBPPT. Furthermore, they performed steady-state running (10km/hr, 14 km/hr, and 18 km/hr) and high-speed running (20km/hr and 22 km/hr) at four different BWs on the LBPPT. VO2, heart rate, ventilation, and breathing frequency as well as vertical ground reaction force (vGRF) and stride characteristics were measured.


RESULTS
VO2max could be obtained on both treadmills, although time to exhaustion was 34.5% longer on the LBPPT. VO2, ventilation, and heart rate decreased linearly with increasing BW support at steady-state running, while breathing rate remained unaffected by increasing BW support. Ground reaction force was markedly reduced with increasing BW support. The contact time decreased and flight time increased with increasing BW support. The step frequency decreased and step length increased to some extent with increasing BW support.


CONCLUSIONS
VO2max can be achieved on an LBPPT at 100% BW with an incline-running protocol. The LBPPT is a suitable training device for athletes and allows training at high running speeds and high aerobic stimuli with the benefit of low vGRF and a near-normal movement pattern, although manipulation of gravitational weight causes some adaptations in locomotion.
Section of Integrated Physiology, Department of Nutrition, Exercise and Sport, University of Copenhagen, Ncrre Alle 51-55, 2200 Copenhagen, Denmark.
Peter C
PC
Raffalt
Line
L
Hovgaard-Hansen
Bente Rona
BR
Jensen
D000328:Adult; D004867:Equipment Design; D005080:Exercise Test / Q000295:instrumentation*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D056152:Respiratory Rate / Q000502:physiology*; D012420:Running / Q000502:physiology*