Understanding the pedal stroke is key to getting more out of each revolution. In this article we look at the leg muscles involved in moving the pedal through 1 cycle.
Down Stroke – Push
At the top of the pedal stroke (00H00/12H00) position the main muscles used are the gluteal muscles. They are responsible for hip extension (straightening of hip joint)
At 01H30 the knee extension (straightening) begins. The muscles responsible for this are on the front of the thigh (quadriceps aka. Quads)
The 2 Muscle groups Glutes and Quads work together from 01H30 – 04H00 to extend the hip and knee. A lot of power (torque) is generated through this phase. The quads continue to work until 05H30 to straighten the leg.
From 05H00 – 06H30 the Calf muscles start to contract and cause ankle plantarflexion (pointing the toes down). Thin in an effort to have one last push
Up Stroke – Pull
The beginning of the up stroke begins with the muscles on the front of the shin (Tibialis Anterior) bringing the foot back to level, ankle dorsiflexion. This happens from 06H30 – 07H30.
The big muscles on the back of the thigh hamstrings perform the most work on the upstroke. When they contract, they cause knee flexion. (bending the knee). This happens from 07H00 – 10H30.
The hip flexors are the last muscles working on the upstroke. Their job is to, flex the hip (bring the knee toward the chest). This happens from 09H30 – 12H00.
Conclusion
At any given time both your legs should be working. When one leg is pushing the other should be pulling. This generates an even distribution of power with a slight drop in power when the feet are at 00H00/12H00 & 06H00. Indicated by the numbers 1 & 2 The two circles join together to form the Peanut shape. The shape is skewed because of the angle of the saddle to the bike.