This study aimed to test the validity of a non-motorised treadmill (NMT) for the measurement of self-paced overground endurance running performance. Ten male runners performed randomised 5-km running time trials on a NMT and an outdoor athletics track. A range of physiological and perceptual responses was measured, and foot strike was classified subjectively. Performance time was strongly correlated (r = 0.82, ICC = 0.86) between running modes, despite running time being significantly longer on the NMT (1264 ± 124 s vs. 1536 ± 130 s for overground and NMT, respectively; P < 0.001). End blood lactate concentration and rating of perceived exertion were significantly higher on the NMT compared to overground. Integrated electromyography was significantly lower on the NMT for three muscles (P < 0.05), and mean stride rate was also significantly lower on the NMT (P = 0.04). Cardiorespiratory responses of heart rate, oxygen uptake and expired air volume demonstrated strong correlations (r = 0.68-0.96, ICC = 0.75-0.97) and no statistical differences (P > 0.05). Runners were consistently slower on the NMT, and as such it should not be used to measure performance over a specific distance. However, the strong correlations suggest that superior overground performance was reflected in relative terms on the NMT, and therefore, it is a valid tool for the assessment of endurance running performance in the laboratory.

The purpose of the study was to establish the reliability of performance and physiological responses during a self-paced 5 km running time trial on a non-motorized treadmill. 17 male runners (age: 32±13 years, height: 177±7 cm, body mass: 71±9 kg, sum of 7 skinfolds: 55±21 mm) performed familiarization then 2 separate maximal 5 km running time trials on a non-motorized treadmill. Physiological responses measured included heart rate, oxygen uptake, expired air volume, blood lactate concentration, tissue saturation index and integrated electromyography. Running time (1,522±163 s vs. 1,519±162 s for trials 1 and 2, respectively) demonstrated a low CV of 1.2% and high ICC of 0.99. All physiological variables had CVs of less than 4% and ICCs of >0.92, with the exception of blood lactate concentration (7.0±2 mmol·L(-1) vs. 6.5±1.5 mmol·L(-1) for trials 1 and 2, respectively; CV: 12%, ICC: 0.83) and the electromyography measures (CV: 8-27%, ICC: 0.71-0.91). The data demonstrate that performance time in a 5 km running time trial on a non-motorized treadmill is a highly reliable test. Most physiological responses measured across the 5 km run also demonstrated good reliability.