Cross training refers to training using different form of exercises from the actual sport to yield similar physiological benefits while avoiding the overuse injuries or burn out from repetitively training with the same method.
Running, swimming and cycling are the three most popular form of aerobic exercises that people participate in to improve their aerobic fitness. Therefore, swimming and cycling are commonly used as cross training methods for runners.
When done at the right intensity, swimming and cycling provides similar aerobic benefits as running. These benefits include increased cardiac output and increased blood volume. This will allow oxygen to be transported to working muscles to produce energy.
Unlike running, swimming and cycling are non weight bearing and low impact exercises. Participating in these exercises will reduce wear and tear of the lower limb joints. Additionally, these exercises also lack in eccentric movement (muscle tension while the muscle is lengthening), which is the main cause of muscle damage that leads to muscle soreness.
Therefore, substituting running with swimming or cycling can help to prevent overused injuries.
Although cross training can help improve aerobic capacity, it will not lead to significant improvement in running performance. This is because running performance is not solely dependent on aerobic fitness. Running performance is also dependent on other factors like movement economy, muscular power and endurance and also anaerobic threshold. These factors can only be improved by doing sport specific training, i.e. Running.
Cross training can aid in preventing overused injuries while providing some benefits similar to the main sport. However, it will not lead to significant improvement in sport performance. Therefore, individuals should participate in cross training as a form of supplement instead of using it as the main form of training. It is recommended that individuals participate in cross training during recovery weeks or during light training days. This will allow the muscles and joints to recover while continuing to benefit their aerobic fitness. Finally, for individuals who train using heart rate as a gauge for intensity, do be aware that as swimming and cycling are non weight bearing exercises, heart rate will be about 10 beats per minute lower as compared to running, when performing at the same intensity.