Take a look around the athlete prep area before your next race. You will see athletes laser-focused while they work themselves into a lather, preparing for the intensity of the race to come. The logic is that if you open up your body during warm-up, then your body will respond well to the rigors of the race rather than lock-up. The problem is that too much of a good warm-up turns it into a bad warm-up. The length and intensity of a traditional warm-up has long thought to give athletes an edge by eliciting a response called post-activation potentiation (PAP). An athlete triggers PAP when he adds interval work to the warm-up. What is less well-known is that (1) the benefits of PAP last for only 5-10min once the warm-up is concluded; and (2) fatigue from warming up too extensively negates the positive impact PAP plays.
In research presented in the "Journal of Applied Physiology", scientists compared a traditional 50- minute warm-up with high-intensity intervals to a 15-minute warm-up with moderate-intensity intervals in 10 highly-trained track cyclists. The researchers found that the shorter warm-up group experienced less muscle fatigue and produced higher peak power outputs in an ensuing stress test. In other words, the cyclists that warmed up for just 15-minutes had fresher legs than those that used a traditional, 50-minute warm-up – and they performed better.
Additionally, in a recent study in the "International Journal of Sports Physiology and Performance", researchers warned that, “Warm-up exercise including race-pace and sprint intervals combined with short recovery can reduce subsequent performance in a four-minute maximal test in highly trained cyclists.” The cyclists in the study group that included high intensity warm-up intervals exhibited less peak power in a subsequent maximal exercise test. The study’s authors recommended that an ideal warm-up should be shortened or performed at reduced intensity. The effects of heightened fatigue from too long a warm-up last more than 30 minutes. In other words, well into the early stages of the race.
With this in mind, it would behoove athletes to shorten their warm-ups to a maximum of 15-20 minutes and include some short sub-threshold intervals with adequate recovery between rather than performing those intervals at a higher intensity and producing unnecessary (and counterproductive) fatigue. Give the shorter warm-up idea a shot at your early-season races, and even during your upcoming interval sessions. You may find that spending less time warming up is actually the key to better performances.