FIVE-KILOMETER TIME TRIAL RELIABILITY OF A NONMOTORIZED TREADMILL AND COMPARISON OF PHYSIOLOGICAL AND PERCEPTUAL RESPONSES VS. A MOTORIZED TREADMILL

摘要

This study examined the reliability of running performance across 3 nonmotorized treadmill (NMT) 5-km time trials (TTs) and physiological, gait, and perceptual differences at a 5-km pace for both NMT and motorized treadmills (MTs). Ten male runners experienced in road racing who had never run on an NMT completed 3 TT to establish personal best 5-km pace. In a later session, participants ran at this pace for 5 minutes on the NMT while metabolic, gait, and perceptual measures were recorded and then ran at outdoor 5-km personal best pace on an MT at 1% grade (counter-balanced crossover design). Intraclass correlation (ICC = 0.95) between the TT1 and TT2 was strong but improved between TT2 and TT3 (ICC = 0.99) with considerable reduction in variability. Nonmotorized treadmill resulted in a 24% slower pace (10.6 +/- 1.5 vs. 13.9 +/- 2.6 km.h(-1); 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 per.minute; p = 0.01). However, Vo(2), respiratory exchange ratio (RER), lactate concentration, and heart rate did not differ between modalities (NMT = 3.4 +/- 0.4 L.min(-1) , 0.96 +/- 0.04, 6.9 +/- 3.7 mmol, 172 +/- 10 b.min(-1); MT = 3.4 +/- 0.5 L.min(-1) , 0.96 +/- 0.04, 5.7 +/- 3.4 mmol, 170 +/- 10 b.min(-1)). rate of perceived exertion (RPE) for legs, breathing, and overall did not differ between treadmill types. A familiarization session should be included for TT using NMT. Other than gait and pace characteristics similar responses were elicited by both treadmills when running at 5-km pace. However, with these considerations, NMT TT of 4-km might be more appropriate in matching MT 5-km TT duration without altering physiological responses significantly.