Heavy power training besides endurance training has a positive effect on endurance performance in cycling and running. This follows from a thorough literature review on the effect of power training on endurance performance, conducted by two experts in this field.


While it seems logical to do mainly endurance training for improving endurance performance, for some time it has been clear that power training can improve endurance performance. Rønnestad and Mujika summarized in this review, the results of numerous studies on the effects of combining strength and endurance training on endurance performance. They also have investigated the mechanisms by which weight training can promote endurance performance.


Power training can improve running economy and cycling economy. Furthermore, maximum speed and maximum power improves when athletes do power training. Also, the quality of the control of the muscles increases, which has a positive effect on the rate of the strength development (also called the rate or force development, called RFD).  Thanks to a higher maximum strength athletes can sustain efforts at submaximal level longer. The glycogen stores are depleted later and the muscles fatigue less quickly. The athlete can also accelerate or sprint better during the race because the muscles are less fatigued and that is the reason the athlete can reach a higher maximum speed.


The immediate effect that a combined strength and endurance training has on endurance performance has also been studied in a large number of studies. The results of a small number of these studies found no improvement in performance. This is according to Rønnestad and Mujika, however, probably because these studies were very short in scope and that they used a low volume of power training. In studies with positive results the athletes did power training for at least 8 weeks with heavy exercises for the leg muscles, resulting in a performance enhancement during exertions of 2 hours or more.  As a result of power training hypertrophy may occur: this means that the muscle size increases by training. This can be disadvantageous for athletes who have to move their own body weight. Several studies, however, showed no increase in body weight after a period of combined power and endurance training. The VO2max of the athletes remained stable.


It is advisable to schedule strength at the start of the season. Two power training sessions per week in 12 weeks lead to clear adaptations in the muscle. This requires athletes to do 2 to 3 series with heavy weight training (80 to 90 of 1 RM). Athletes should mainly train the muscle groups and movements that they can use during the races. During the race season one power training workout per week is sufficient to maintain the benefits of power training.