The one piece of advice I would give to someone concerning strength training and cycling would be to learn how to fire the hamstrings correctly and to train them to be as strong as possible. The reason for this is because the back side mechanics of an effective cycling stroke is not an intuitive or practiced motion like the quad dominated front portion. The role of the hamstring is also very complex in that it needs to contract isometrically to add tension for knee stability, then contract concentrically to aid in both hip extension and knee flexion. There’s a lot going there and it can take a while to make the whole thing feel normal and powerful.
Step One – Feel them working while you are on the bike. There is nothing like an indoor bike when it comes to discovering your hamstrings. Set the bike up as normal, clip in or strap yourself to the pedals and ride for 5 minutes to warm-up the body. Once you are ready to work, release one of your legs and put the free foot on the cross bar just above the crank. Correct your posture, engage your abs and start pedaling paying particular attention to your crank speed. You want to feel like you are powering the entire time vs. just as you press down at the top. It may be helpful to think about making a “J” shape with the ball of your foot from 5 o’clock to 9 o’clock (as the foot moves down, back and up). It will be a lot easier to feel them working if your core is tight and you are stable on the saddle. Do this for a few minutes then switch to the other leg. After 2 or 3 sets of 2-3 minutes, clip in with both feet and focus on making the speed more even. Do this 2-3 times per week for 4-6 weeks and you’ll notice a huge improvement in your power output.
Step Two – You need to train your hamstrings be strong during the isometric and concentric phase of hip extension and strong during the concentric phase of knee flexion. They are mostly isolated when they are trained as knee flexors, so keep the rep range here between 6-12 and focus on a quick concentric contraction. When they are trained as hip extensors (stiff leg / Romain dead lifts, good mornings, back extension, kettle bell swings, battle ropes) the contraction should be quick and the rep range should be higher between 10-25. When they are trained eccentrically (glute ham raises) the lengthening motion should be between 4-8 seconds and the rep range between 4-8.
Step Three – You need to understand how and when the hamstrings generate the most power and work with that. Given that the hamstrings play a key role for knee stability with sprinting they tend to be made up of a high percentage of fast twitch fiber. They are also not very active as we break inertia – meaning we get very little out of them in terms of force production with slow concentric contractions. However, as they begin to contract more quickly, they start to contribute more output. So, as with training, when you are on the bike you need to contract them as quickly as possible and this is only going to happen when you are cranking at a minimum RPM – about 65-70. At this speed, your legs are moving quickly enough for the hamstrings to contract with sufficient speed to drive considerable force to the pedals. Anything slower than this and they lose much of their efficiency and output.
Once you have become proficient at recruiting the hamstrings with the pedal stroke, you may find that your riding improves by switching focus from the quads to the hamstrings, particularly after cresting a hill, accelerating and sitting in the saddle as your quads tend to be more active during standing hill climbs and they will benefit from the recovery that a shift in work onto the hamstrings brings.
Regardless of what you do with the new awareness, your riding will improve dramatically once you begin to use your hamstrings when you cycling, and your performance will improve dramatically once you start to train your hamstrings with the specific goal of getting stronger.