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Validity and Reliability of the PowerCal Device for Estimating Power Output During Cycling Time Trials
Vitor P Costa1, Luiz G A Guglielmo, Carl D Paton
11Center for Health and Sport Science, Department of Physical Education, Santa Catarina State University, Florianópolis, Brazil; 2Physical Effort Laboratory, Department of Physical Education, Federal University of Santa Catarina, Florianópolis, Brazil; and 3Exercise Physiology Laboratory, Faculty of Health and Sport, Eastern Institute of Technology, Napier, New Zealand.
Abstract:
Costa, VP, Guglielmo, LGA, and Paton, CD. Validity and reliability of the PowerCal device for estimating power output during cycling time trials. J Strength Cond Res 31(1): 227-232, 2017-This study assessed the validity and reproducibility of the PowerCal device for estimating power output (PO) during cycling hilly time trials (TTs). Twenty-one well-trained men cyclists performed an incremental exercise test and three 20-km TTs (34.1 ± 10.6 years; 73.2 ± 3.2 kg, 176.8 ± 6.2 cm; maximal PO, 334 ± 31 W; maximal oxygen uptake, 61.0 ± 4.2 ml·kg·min). The first TT was used for familiarization, and the tests were separated by at least 72 hours. Mean PO over the 20-km TT was significantly greater for the Velotron (282 ± 27 W) than for the PowerCal (242 ± 28 W). The mean power over each kilometer of the trial ranged from 5.8 to 23.4% greater on the Velotron than on the PowerCal. High within-subject variation between the trials was substantially greater for the PowerCal (4.9%) than for the Velotron (1.8%). High coefficients of variation scores for the Velotron test-retest were found to be concentrated in the beginning and final meters of the TT (∼6.0%), whereas the scores were lower in the middle of the trials (∼3.0%). In contrast, the PowerCal test-retest achieved a high coefficient of variation (∼6.0%) in each km over the TT. Thus, the PowerCal device should be used with caution during cycling activities because it is not reliable and underestimates PO.
