Affiliations: [a] Physical Effort Laboratory, Faculty of Physical Education, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil | [b] Faculty of Sports Science, Eastern Institute of Technology, Napier, New Zealand
Correspondence:
[*]
Corresponding author: Vitor Pereira Costa, Physical Effort Laboratory, Federal University of Santa Catarina, Campus Universitário Trindade, Florianópolis, Santa Catarina, Brazil. CEP: 88040-900. Tel.: +55 048 3721 4774; Fax: +55 048 3721 9772; E-mail: costavp2@yahoo.com.br
Abstract: BACKGROUND: The PowerCal device purports to effectively estimate
power output (PO) using an algorithm computed from the HR response recorded during exercise.
OBJECTIVE: To assess the reproducibility and validity of PO
estimation using the PowerCal during sprints.
METHODS: Ten well-trained male cyclists (maximal oxygen uptake
-62.7 ± 5.9 ml ⋅ kg-1⋅ min-1) performed four separate experimental trials over a two-week period. Cyclists completed an incremental exercise test until volitional exhaustion followed by three maximal sprint sessions on separate days. Each sprint session consisted of 3 repeated maximal-effort sprints (15, 30, and 45 s) formatted with an effort/recovery duration ratio of 1:5.
RESULTS: Peak power output (PPO) and mean power output (MPO) of the PowerCal showed high within-subject variation (6.7 to 21.5%) and low to high intra-class coefficient of correlation (ICC = 0.39 to 0.85).
Furthermore, the PPO from PowerCal was underestimated by 6.6 to 13.9% and the MPO by 14.9 to 27.6% when compared to the Velotron. Furthermore, the data exhibited high bias (32 W to 129 W) and large confidence limits (-236 to 315 W) between the PO derived from the Powercal and the Velotron.
CONCLUSION: We do not recommend competitive cyclists or sport
scientists to use the PowerCal if reliable and valid PO information is
required during maximal sprints.
