Fat Oxidation During Ambulation On A Normal And Lower Body Positive Pressure Treadmill

Lower body positive pressure treadmills (LBPPT) decrease ground reaction force by providing a lifting force as the treadmill chamber is inflated. These treadmills can be a beneficial exercise for larger patients with greater body fat. Fat oxidation (FatOx) is a function of exercise intensity and caloric expenditure. PURPOSE: To compare FatOx on a LBPPT and normal treadmill (NT) at different exercise intensities. METHODS: FatOx was measured using indirect calorimetry during a treadmill walking protocol. Ten apparently healthy college-aged female volunteers completed the following exercise protocol: standing, warm-up at 58.96 m × min-1, and exercise at 88.44 m × min-1 with a 3% grade increase per stage on NT and LBPPT. Each stage was 3 minutes. The LBPPT was set at 80% of normal body weight. Metabolic data were collected every 15 seconds. Each volunteer fasted prior to participation. Steady state (SS) was considered the last minute of each stage. Volunteers completed all 7 exercise stages or when the respiratory exchange ratio (RER) reached 0.95. RESULTS: FatOx rate was calculated based on SS VO2 and VCO2 measurements. Repeated measures ANOVA was run on treadmill type and 6 stages of the protocol (rest, warm-up, stage 1, 2, second to last stage, and last stage). There was a statistically two-way interaction between treadmill type and stage, F(3,45) = 52.18, p < 0.001. Implying that fat oxidation rate depends on the treadmill type and exercise intensity. Simple main effects were determined for treadmill type and stage. Pairwise comparisons for NT showed that FatOx was significantly lower for the last stage and at rest compared to the other stages (p < 0.05). Pairwise comparison showed mean FatOx did not change over the exercise stages on the LBPPT. Highest measured FatOx on NT was 0.54 g × min-1 and on LBPPT was 0.44 g × min-1 both occurred during the penultimate stage. CONCLUSION: Current study demonstrates greatest FatOx on NT at moderate exercise intensities. The current protocol was not able to elicit an identifiable maximal FatOx on the LBPPT.