Andy Bowen,MS, PT
Posted April 1st, 2006
Fitness, technique and position on your bike are all factors that can
increase or decrease your riding performance and your risk for a
While Vermont’s Snow Gods were hibernating, the Cycling Gods blessed us with 50-degree weather in January and February. The weather was pretty pathetic for skiing, but pretty sweet for aerobic base-building bike rides.
“Who has time to base build?” you ask. You probably don’t even have time to read this article. You’re lucky to fit your daily anaerobic workout in to ease your mind and release your stress. But if your priority is surviving your long workweek, then your remedy is a quick fix of sweat. Hopefully, that fix is a long ride outside in the sun.
Rider beware! You’re not getting any younger, so at some point you may not be able to make the switch from winter activities to cycling so easily. If you plan to ride much this coming season, and you did not take advantage of the off-season with a strength-training program to address your weaknesses, then your cycling season may be as lame as this ski season. Fitness, technique and position on your bike are all factors that can increase or decrease your riding performance and your risk for a cycling injury.
So if you’re out of shape, at the very least work on your pedaling technique and get positioned properly on your bike. Take advantage of science to improve energy efficiency and decrease the risk of injury.
Efficient pedaling is challenging due to the unnatural movement required of our legs. Walking and running are more natural because our ability to contract muscles is a direct response to the forces generated when a foot hits the ground. These are called ground-reaction forces. This natural muscle contraction in response to ground-reaction forces does not exist when cycling. As kids, we learned to propel a bike forward by thrusting downward on the pedal stroke in order to gain momentum and avoid losing our balance. For many cyclists, use of this downward thrusting technique has not changed so they are not taking advantage of the full 360-degree pedal stroke. This pedal stroke is a circular pattern that our muscles must be taught.
Most cyclists understand the linear aspect of pushing down and pulling up on the pedals. Pedaling in this linear fashion will lead to an inefficient pedal stroke with a “dead spot” at the top and bottom of the stroke. We know from physics that it takes more energy to put a mass in motion than it does to keep that mass in motion. Therefore, providing continuous 360-degree power to the rear wheel will keep you in constant motion at a lower cost of energy. That power is transferred by the pedal stroke.
The quads, hip flexors, tibialis anterior and buttocks help power the top of the pedal stroke, while hamstrings and calves help power the bottom. Every cyclist needs to strive to use these muscles during the respective phases of the pedal stroke by thinking “circular” instead of “linear”– think of the small circle the pedal cranks create and try to provide constant power throughout this full 360-degree revolution. As you increase your ability to produce consistent power throughout the circular pedaling pattern, it should remain constant. The speed and the force applied are the factors you change to increase the velocity of the rear wheel.
Another pitfall is “ankling,” or locking the ankles. The gastrocnemius muscle (calf) assists knee flexion during the bottom and upstroke of the pedal pattern. Locking ankles will decrease this knee flexion power. To “unlock,” try flexing
and extending your ankle as shown in the above diagram.
Also, make sure to keep your knee in the same plane as your pedal stroke. A common mistake is internally rotating each knee over the bike’s top tube during the downstroke. You will not only lose power this way, but also increase your risk of medial knee (medial patella retinaculitis) and hip (piriformis syndrome) overuse injuries
Hopefully, your cycling position encourages proper biomechanics so you can produce more power with less joint stress and muscle fatigue. All muscles have an optimal length at which to generate the most power. Muscles are made of protein filaments called actin and myosin. If these filaments are positioned so that the maximum number of cross-bridges are formed, then maximal power can be produced. For instance, a 25- to 30-degree knee angle provides the optimal length for your knee muscles to produce power. If you are positioned properly on your bike, then each joint, from head to toe, should be placed in its optimal position giving you a huge mechanical advantage.
Do not sacrifice comfort for a high performance or aerodynamic position on your bike. Riding in pain is a waste of energy and may lead to big trouble in the long run. We want to see you on the road or singletrack, not in the clinic. Have a great season!