The physiological and perceptual demands of running on a curved non-motorised treadmill: Implications for self-paced training

Objectives: To compare physiological and perceptual response of running on a curved non-motorized treadmill (cNMT) with running on a motorized treadmill (MT), and to determine the running velocity at which a physiological response >= 90% <(V)over dot>O(2)max was elicited. Design & methods: 13 trained male runners (mean +/- SD; 36 +/- 11 years, 1.80 +/- 0.06 m, 70 +/- 4 kg, <(V)over dot>O(2)max: 57.3 +/- 3.5 mL kg(-1) min(-1)) performed an incremental running test on a MT to determine <(V)over dot>O(2)max and the accompanying maximum velocity (Vmax). Participants first completed a familiarization session on the cNMT. Next, participants ran for 4 min at five/six progressively higher velocities (40-90% Vmax). These runs were completed on the cNMT and MT in two separate visits in a randomized and counterbalanced order. Results: No participant was able to complete the 4 min run at 80% Vmax on the cNMT. Running on the cNMT elicit a higher relative oxygen uptake (%<(V)over dot>O(2)max) across all velocities compared to the MT (32.5 +/- 5%, p < 0.001, ES 3.3 +/- 0.9), and was accompanied by significantly higher heart rates (16.8 +/- 3%, p < 0.001, ES 3.4 +/- 1.5), an altered cadence (2.6 +/- 0.7%, p < 0.001, ES 0.8 +/- 0.3) and ratings of perceived exertion (27.2 +/- 5%, p < 0.001, ES 2.3 +/- 0.6). A less efficient running economy was evident when running on the cNMT (+38.4 +/- 16%, p < 0.001, ES 2.73). Individual (n = 9) linear interpolation predicted an exercise intensity of 90% <(V)over dot>O(2)max was achieved in the non-motorized condition when running at 62.1 +/- 3.5% Vmax (R-2 = 0.986 +/- 0.01), which was lower than MT run in which 90% <(V)over dot>O(2)max was achieved at 81.4 +/- 5.6% Vmax (R-2 = 0.985 +/- 0.02; 29.8 +/- 8%, p < 0.001, ES 3.87). Conclusions: Running on the cNMT has higher physiological and perceptual demands and increases cadence. (C) 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.