Physiological, Gait, And Perceptual Responses At 5-km Race Pace On Motorized Vs. Non-motorized Treadmills: 3646 Board #93 June 3 8

PURPOSE: This study examined physiological, gait, and perceptual differences of running at 5-km race pace on a non-motorized (NMT) versus a traditional motorized treadmill (MT). METHODS: Trained (VO2max = 53.0 ± 6.8 ml/kg/min) male runners (n = 11) of varying skill level and age (30 ± 10 y) completed 3, 5-km time trials on a NMT. During a later session, the average finishing time of the trials was used as the goal pace to maintain during a 5 min run on the NMT. Participants also ran at their personal best 5-km race pace within the last 6 months on a MT for 5 min with a 10 min rest period between bouts (counter-balanced crossover design). RESULTS: NMT resulted in a slower pace (10.6 ± 1.5 vs 13.9 ± 2.6 km/h; p < 0.001), shorter stride length (1.02 ± 0.10 vs 1.27 ± 0.18 m; p < 0.001), and decreased cadence (175 ± 12 vs 181 ± 13 steps/min; p = 0.01). However, VO2 (NMT = 3.4 ± 0.4; MT = 3.4 ± 0.5 L/min), RER (NMT = 0.96 ± 0.04; MT = 0.96 ± 0.04), lactate at 3 min into recovery (NMT = 6.9 ± 3.7; MT = 5.7 ± 3.4 mmol), and heart rate at the end of each trial (NMT = 172 ± 10; MT = 170 ± 10 bpm) did not differ significantly. Likewise, RPE for legs, breathing, and overall did not differ significantly between treatments. CONCLUSION: Although gait and pace were altered significantly, physiological and perceptual responses between the MT and NMT were similar. NMT time trial testing can be expected to elicit similar endurance exercise stresses when a more “free” running task is desired, but interpretation of results need to be made with the consideration that performance is expected to decline by ~25% or more likely due to excess resistance from the NMT belt.