In the triathlon and cycling communities, many of us have power meters on our bikes, or smart trainers at home. Power output data can be helpful in pacing efforts and tracking longer term progress. I myself programme many of my training sessions using power output – e.g. 4 x 40 min at 270 W for an Ironman workout – with the target number guided by the laboratory-based physiological profile of the athlete I am working with. For example, in the session above, the target power output is designed to be just above the first lactate threshold, in the so-called heavy intensity domain.

However, not all athletes have regular access to laboratory facilities for physiological profiling assessments and the determination of thresholds. For those athletes, power profiling represents an alternative, field-based method that can be used to provide anchor points in our training programming. Also, power profiling may be used to provide a still-elusive ‘durability’ metric. In...