Most experts recognize — and relevant literature supports — that endurance athletes benefit from both heavy resistance and endurance training. Maximal strength and power training have recently gained attention as a potential strategy for increasing endurance performance.
A recent review of the literature concluded that concurrent training (the simultaneous training of resistance and endurance exercise) has a positive effect on endurance performance.
One determinant of sport performance is the ability to appropriately and effectively exert force into the ground (e.g., running, jumping) or an apparatus (e.g., cycling). When all other factors are equal, the athlete with a greater ability to exert force will perform the best, as they will cover more distance per muscle action. Therefore, even endurance athletes benefit from increases in force production.
According to a recent Strength and Conditioning Journal article, strength training improves motor recruitment patterns, which lowers energy expenditure at any specific submaximal intensity because fewer motor units (and therefore muscles) are activated. Any adaptation that allows an athlete to use less energy at a given speed will decrease the oxygen requirement and should therefore increase athletic performance. Moreover, less muscular contraction leads to less blood flow restriction, which allows greater delivery of fuels and removal of waste products. High-intensity power training (such as plyometrics) offers extra benefits, as it enhances efficiency of elastic energy by increasing musculotendinous stiffness (a measure of how readily tissue reforms after being stretched, compressed, or twisted). This shifts energy production from active (muscular contraction) to passive (elastic rebound) sources. (Martuscello, Jason MS, CSCS, HFS; Theilen, Nicholas MS)
Please see related article, Plyometric Training Benefits Distance Runners.
The addition of strength and power training should be done with caution, in order to avoid overtraining. Strength and conditioning professionals need to be aware of proper periodization principles and specifically control volume and frequency throughout the training cycle to reduce this risk. The relationship between strength training and endurance training should be inverse. The addition of strength and power training should be countered with the subtraction of some endurance training, and vice-versa. For example, replacing approximately 1/3 of endurance volume with explosive strength training has been shown to improve leg strength, speed, power, anaerobic capacity, running economy, and most importantly 5k running time.
Strength and power training has many benefits for endurance athletes, including improved force output, musculotendinous stiffness and elastic energy efficiency, running economy, and race performance. In order to minimize the risk of injury, proper monitoring of program design and exercise technique should be closely observed.
