Abstract
Introduction & Aims: With changes in cycling performance as small as 1% determining the difference between a finish on the podium and a finish within the peloton, the ability to accurately monitor training and competitive performances in trained cyclists is significantly important. Ergometers that replicate cycling are invaluable pieces of laboratory equipment that can be used to conduct physiological fitness assessments, enable structured training sessions and monitor training responses. Given that cyclists may ride in excess of 35,000 km per year, the ability to replicate individual training and race-specific variables as closely as possible is highly desirable and more achievable when the cyclists own bike can be used. Therefore, the aims of the present study were to assess the validity of power output settings of the Wahoo KICKR Power Trainer (KICKR) using a dynamic calibration rig (CALRIG) over a range of power outputs and cadences. Methods: Using the KICKR to set power outputs, powers of 100-999W were assessed at cadences (controlled by the CALRIG) of 80, 90, 100, 110 and 120rpm. Results: The KICKR displayed accurate measurements of power between 250 and 700W at cadences of 80-120rpm with a bias of -1.1% (95%LoA: -3.6-1.4%). A larger mean bias in power were observed across the full range of power tested 100-999W (4.2%: 95%LoA: -20.1-28.6%), due to larger biases between 100-200W and 750-999W (4.5%: 95%LoA: -2.3-11.3% and 13.0%: 95%LoA: -24.4-50.3%, respectively). Conclusion: When compared to a dynamic calibration rig, the Wahoo KICKR Power Trainer has acceptable accuracy reporting a small mean bias and narrow limits of agreement in the measurement of power output typically observed in trained cyclists when performing time trials ranging from 4 to 40 km (250-700W at cadences of 80-120rpm). Caution should be applied by coaches and sports scientists when using the KICKR at power outputs of 750W due to the greater variability in recorded power.