Evaluating a cyclists’ pedal power and generating an appropriate bicycle fit
Authored by Brad Brown.
Most cyclists do a good job working their pedal-pushing muscles. They build strength and power in their quads and glutes when they are on the bike and (hopefully) back it up through leg presses and squats at the gym. But unless you do a lot of single leg pedalling drills or otherwise consciously work the pedal-pulling hamstrings on the back of your thighs, chances are they’re neglected and relatively weak by comparison.
A cycling assessment will evaluate your pedal power. It is a service provided by a physiotherapist as part of a cycling or rehabilitation plan. Trained physiotherapists can help cyclists evaluate their performance and provide expert advice on techniques that can help your overall strength and rhythm.
When done in conjunction with a specialist bike fitting session, each cyclists’ unique biomechanics can be clinically assessed, and their force production can be determined.
Force production to the pedals can be affected by many factors, the purpose of a bicycle fitting session and assessment is to match these factors to achieve the persons’ desired outcome.
During a physio-led bicycle fitting session, a physio evaluates pedal placement to ensure a position that supports an efficient and consistent ride.
Other factors considered include:
- Cycling technique- the coordination of flexion to an extension of the hip, knee and joint angles resulting in the propulsive torque during the downward action phase, and resistive action during the recovery phase as the crank revolution returns to the propulsive phase
- Muscle workload- the balance between generating power and controlling muscle activation to prevent fatigue
- Changing pedalling cadence – this can improve the force-velocity relationship for each muscle, the coordination of muscle activation timing and therefore more consistent anticipation of muscle contraction to increase power transfer. Most cyclists opt for a cadence of between 80-100 rpm.
- A change in body position is critical in dictating muscle activation; most prominently upper body lean and seat height. A change of up to 4cm in terms of seat height can alter muscle activation with large impacts on cycling economy, where small changes can be detrimental to pedal power.
- Apart from tried-and-tested trial and error—moving foot position, changing shoes, or adjusting cleats yourself based on feel—a physio-led bike-fit will employ their expertise in biomechanics to determine the relationships between your body and the bike for an optimal fit. You won’t get force-based feedback about efficiency, but you’ll end up in the position most likely to do you good.
Comfort and effective pedalling technique are essential for anyone who wants to maximise their potential on a bike. By riding on a correctly fitted bike you will be able to ride faster for longer.
Brad Brown, Physiotherapist and Professional Bicycle Mechanic at Lifecare Prendiville
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