As endurance athletes, we know that getting enough volume into our training programme is critical in our preparation for an event, and we know that to get enough volume without becoming overreached and overtrained, we need to manage and regulate our training intensities effectively (4, 6). We might therefore plan and programme-specific long-duration training sessions designed to generate low physiological stress within our programme (7). Ideally, we'll use physiological profiling numbers – specifically, knowledge of the power output, running speed, and heart rate at the first threshold or moderate-to-heavy intensity transition – to programme and regulate these sessions (5). For example, suppose we determine that our first threshold occurs at 240 W. In that case, we might cap our long, low-intensity weekend ride at, say ~230 W. We also use this number to help quantify things like training load and how much weekly volume was completed within a specific zone.

This is a...

Dr Dan Plews & Ed Maunder

In this blog, we are going to provide a little detail for athletes and practitioners on how to interpret changes in blood lactate parameters and profiles derived from serial laboratory-based lactate threshold assessments. These assessments typically involve exercising initially at a very low workload, considerably below the aerobic threshold, with heart rate and blood lactate concentration recorded prior to an increase in workload every 3-4 minutes (although these ‘steps’ can be longer). These steps are repeated until exhaustion. Expired gases may be collected throughout, and these can provide insight into movement economy, substrate utilization, and maximum oxygen uptake (VO₂max). The tests are typically performed for (i) training zone identification and (ii) monitoring adaptations to training.

Classic rightward and leftward shifts

Below we have a textbook rightward-shift in the blood lactate vs. power output curve, which we...