Does having big calves naturally affect your running performance? is it a benefit or is it bad?

Calf size and speed: The size of your calves is typically predetermined by your genetic makeup like every other part of your body. Typically the makeup of the type of muscle fiber determines your ability to run faster or slower. The calf is one of many muscles in your entire lower extremity and torso that determine how fast you run and is generally not a detriment or advantage.

Not necessarily: Everyone has a genetic disposition for the inherent shape of your body. Some people have big calve muscles naturally. The only caution is that you may be more prone to calf strains(tear of muscle) or achilles tendonitis and forefoot (ball of your foot) complaints. People with large calve muscles need to warm up and stretch calve muscles out before and after running.