Knowing which muscles are used when cycling can make an enormous difference to your ride. Anyone who has spent any time on a bike will know that cycling can make for a challenging workout, and can push your heart rate way up towards its maximum if you work hard enough. The most noticeable side-effect of a tough ride, though, is the burning sensation in your legs. 
In the dead spot of the pedal stroke, from six to nine o’clock, the calves provide a little force to get over the top of the pedal stroke. The front side of the lower leg, the tibialis anterior, for a moment becomes a star in that six to nine o’clock range when it is the only muscle working to get that leg over the dead spot.
The lower leg can be impressive in appearance, but in reality, it provides little of the force from a cyclist’s legs. The size and shape is not an indicator of a rider’s strength. At a given level, most of those factors are genetic. Calves will tell you nothing of a rider’s ability. No need to be intimidated by chiseled calves.
"These muscle groups have been described as having different contributions at different phases of the pedal cycle, and different muscles within these groups can also be assumed to have different functional contributions."
However, despite its "essential" role in the pedal stroke, the study by experts at the Scandinavian Journal of Rehabilitation Medicine found that the tibialis anterior was less activated than during walking – meaning cycling could cause less strain here than some other activities. "It is suggested that cycling might be a useful exercise in the rehabilitation of patients with injuries to the anterior cruciate ligament, medial collateral ligament of the knee or Achilles’ tendon," the researchers wrote.
