Cycling can improve your cardiovascular fitness which is important for running performance. Your cardiovascular fitness is your body's ability to deliver oxygen to your muscles during exercise. The more oxygen your muscles receive, the better they can perform. Cycling can also improve your endurance and stamina, which can help you to run for longer periods of time.
Research has shown that cycling can be an effective form of cross-training for runners. A study published in the Journal of Strength and Conditioning Research found that runners who added cycling to their training program improved their running economy, which is a measure of how efficiently a person runs. The study showed that the runners who cycled had a significant decrease in the amount of oxygen they needed to maintain a certain running pace, indicating an improvement in their running economy.
Cycling also provides a low-impact form of exercise which can help to reduce the risk of injury when running. Running is a high-impact activity that places a lot of stress on your joints, especially your knees. By cycling, you can give your joints a break while still improving your fitness.
It's important to note that cycling and running use different muscle groups, so it's important to continue to include running-specific training in your overall training plan. For example, running requires more hip and ankle flexion, while cycling requires more knee extension. Therefore, including strength training for these muscle groups and doing specific running drills would be beneficial as well.
- "The Effects of Cycling Training on Running Performance" by J Strength Cond Res. 2015 Nov; 29(11): 3159–3167.