Knowledge and understanding of the muscle activity during the upstroke of the pedal cycle from a Physical Therapist’s point of view are essential to optimizing power, efficiency, and performance.
Often referred to as the Upstroke, the Recovery Phase is the portion of the pedal stroke during which force is no longer applied downward, between 6 and 12 o’clock (180 to 360 degrees).
The upstroke is the little brother to the Power Phase, which cyclists rightfully and undoubtedly believed to be crucial to performance. Many riders overlook the upstroke. There may be a good reason for that!
Although termed the recovery phase, there is debate whether our legs are actually resting during the upstroke or if muscle force is required and necessary to pull the pedal upward.
An overview and analysis of this often neglected portion of the pedal stroke will make it more transparent and provide insight into using the upstroke to our most significant performance advantage.
The pedal stroke has been intensely scrutinized, and there are several contrasting theories, each with its merit and compelling evidence. It is not my intention to tell you which is the right one. I have taken a different approach and utilized my physical therapy experience to dive into this topic from a different perspective.
You will find a similar perspective in The Power Phase of the Pedal Stroke previously posted to The ZOM.
The Pedal Stroke in Greater Detail
A more detailed breakdown of the pedal stroke divides it into 4 phases distinguished as follows:
The Role of the Muscles on the Front of the Shin
During the initial portion of the upstroke, between 6 and 8 o’clock, the muscles on the front of the shin (the tibialis anterior) contract as the foot is unweighted and the transition occurs. The anterior tibialis muscle pulls the toes towards the front of the shin, drawing the foot upwards and applying an upward force on the pedal.
The Role of Hamstrings
From 8 till 10 o’clock, the muscles of the hamstrings (the biceps femoris, semimembranosus, and semitendinosus), contract to pull the foot toward the buttocks. This upward motion creates a bending (or flexion) of the knee.
The Role of the Muscles on the Front of the Hip
The hip flexor muscles (the psoas and iliacus), located on the front of the thigh, are activated between 10 and 12 o’clock. The hip flexors act to complete the upward portion of the recovery phase by pulling the knee towards the trunk, preparing the leg for the initiation of the downstroke. More on this in the article The Psoas Muscle…Pso Why is it Pso Important to the Cyclist?
The ‘Pulling the Pedal’ Myth
While it is exciting and valuable to know the muscles utilized during each aspect of the pedal stroke, those activated during the recovery phase are of minor importance to the overall force produced during pedaling. In fact, ‘pulling the pedal’ is arguably a myth, and there is little if any power benefit (less than 5%) to doing so.
Moreso, the pedal is acting to push your foot upward, and the most efficient pedalers lose the least amount of power by getting it out of the way.
The upward force generated by the hamstrings, hip flexors, and shin muscles is of greater emphasis when climbing, especially during out of the saddle efforts.
Unequal Power Produced During the Pedal Stroke
The force produced while cycling always contributes 100% to its motion. That is to say, we lose no energy in applying force in the wrong direction.
Power isn’t applied equally around the entire pedaling cycle, however. We produce significantly more power during the downstroke than during the upstroke.
Our quads and glutes are much more efficient and effective at applying pressure while extending the leg than our hamstrings are at bending our knee and hip. In addition, if force were to be produced equally during the entire stroke, there would be no time to rest, and that just isn’t realistic.
The Transitions are Key
It is essential to train the transitions. By becoming efficient at applying force and focusing on eliminating periods of little to no force production (dead spots), the change from downstroke to upstroke, and vice versa, is more effective. Rather than focusing on pulling the pedal to improve our pedaling power, we should spend our time on smooth transitions.
In this area, the Pros differentiate themselves from recreational cyclists like us. Studies suggest that most professional cyclists are highly efficient at eliminating the dead spots in their pedal stroke, and it shows.
The Role of Bike Fit and Position
Improper or ineffective bike position is a factor in pedal stroke power and efficiency. If your saddle is too high, it hinders the transition from the downstroke to the upstroke and won’t allow you to drive your heel downward.
The opposite is true with a saddle that is too low. More importantly, it produces excessive stress upon your knee, increasing the risk of overuse injury.
In addition, if you position your saddle too far backward or your crank is too long, a more significant amount of energy is required to apply force. It produces a dead spot during the backstroke transition.
If your crank length is too short, the muscles used during the power phase of the pedal stroke are in a less-optimal position to contract most effectively, and you generate less power.
A breakdown of the power phase, or downstroke, allows for a clear and logical approach to the implications of its components. While the knowledge may not be as essential, we can ascertain a performance edge through awareness of the pitfalls of improper upstroke technique and the causes.
Pedaling power and efficiency are essential and can be improved by focusing upon technique. There are ways to train for a smooth, supple stroke.
In our never-ending search for marginal gains, training for optimal pedaling efficiency is yet another potential source. We will explore this vital topic further in a future article.
How is your pedaling?
Do you think you have a smooth pedal stroke? If yes, what makes you think that way? Comment below. Your fellow virtual cyclist would appreciate your insight.
Semi-retired as owner and director of his private Orthopedic Physical Therapy practice after over 20 years, Chris is blessed with the freedom to pursue his passion for virtual cycling and writing. On a continual quest to give back to his bike for all the rewarding experiences and relationships it has provided him, he created a non-profit, and through its work and the pages of this site, Chris is committed to helping others with his bike. His gain cave is located on the North Fork of Long Island where he lives with his beautiful wife and is proud of his two college student children.