An Analysis of Variability in Power Output During Indoor and Outdoor Cycling Time-Trials

Owen Jeffries, Mark Waldron, Stephen D. Patterson, Brook Galna
2019 International Journal of Sports Physiology and Performance  
35 Purpose: 36 Regulation of power output during cycling encompasses the integration of internal and external 37 demands to maximise performance. However, relatively little is known about variation in power output 38 in response to the external demands of outdoor cycling. We compared mean power output and the 39 magnitude of power output variability and structure during a 20-min time-trial performed indoors and 40 outdoors. 41 Methods: 42 Twenty male competitive cyclists (̇O2peak 60.4 ± 7.1
more » ... peak 60.4 ± 7.1 mL·kg -1 ·min -1 ) performed two randomised 43 maximal 20-min time-trial tests i) outdoors at a cycle-specific racing circuit or ii) indoors on a 44 laboratory-based electromagnetically braked training ergometer, 7 days apart. Power output was 45 sampled at 1 Hz and collected on the same bike equipped with a portable power meter in both tests. 46 Results: 47 Twenty-min time-trial performance indoor (280 ± 44 W) was not different from outdoor (284 ± 41 W) 48 (P = 0.256), showing a strong correlation (r = 0.94; P < 0.001). Within-person SD was greater outdoors 49 (69 ± 21 W) compared to indoors (33 ± 10 W) (P < 0.001). Increased variability was observed across 50 all frequencies in data from outdoor cycling compared to indoors (P < 0.001) except for the very slowest 51 frequency bin (<0.0033 Hz, P = 0.930). 52 Conclusions: 53 Our findings indicate a greater magnitude of variability in power output during cycling outdoors. This 54 suggests that constraints imposed by the external environment lead to moderate and high frequency 55 fluctuations in power output. Therefore, indoor testing protocols should be designed to reflect the 56 external demands of cycling outdoors. 57 58
doi:10.1123/ijspp.2018-0539 fatcat:trefyfxw5zbu5pyfpkjb5s4uqi