A variety of athletes, pro and amateur alike, use ankle weights to enhance their conditioning. Gymnasts may use ankle weights during strength exercises and martial artists during kicking routines to provide greater resistance. Sprinters sometimes use ankle weights to add mass when they do plyometrics -- exercises designed to enhance strength, elasticity and neural speed of the so-called fast-twitch muscles responsible for explosive power. Weightlifters may use ankle weights to strengthen their lower body so they can maintain better balance and stability while lifting. Cyclists tend to not use ankle weights, and for good reason.
The idea behind ankle weights is that by adding weight to your ankles during aerobic exercise, you force your muscles to work harder. Assistant professor of orthopedics at the University of California San Fransisco Anthony Luke told the Los Angeles Times that, “ankle weights make muscles, such as hamstrings, quadriceps and glutes, work harder to do the same motion.” Luke says ankle weights provide a better workout for big muscles and also enhance the cardiovascular benefits of exercise as well.
Luke also notes that ankle weights place more stress on the bones and muscles, which may exacerbate any existing problems you have. Detractors of ankle weights say the additional weight increases the impact loading of joints and causes unnecessary stress. Physician Gabe Mirkin says ankle weights increase the chances of injury because they strengthen the quadriceps in the front of your upper leg without equally strengthening the hamstrings in the back of the leg. He says they force you to work harder to lift your knee and disrupt your coordination. When biking, weights can disrupt your cadence, and can potentially cause you to position your foot differently than you normally do while riding.
There is an additional and perhaps more compelling reason to not bother with ankle weights when biking. The potential benefit of ankle weights occurs because the additional mass causes greater muscular exertion. The problem for bikes is that when you pedal, the weight attached to your left ankle offsets the weight attached to your right ankle, and vice versa. The additional weight on your downstroke makes the upstroke on the opposite pedal easier. The net effect is that you are simply adding weight to the bike and bulk to your ankles. If you want to add weight to your bike for training purposes, you would be better off strapping your ankle weights to the frame of your bike.
Power and Endurance Alternatives
If you want to enhance your speed, power and endurance, you are better off increasing the speed, intensity and duration of your training. Mirkin suggests that in training, you should practice precisely the same movements, coordination and muscular exertions that you do in your sport. To enhance your strength, find some long hills to climb. If you are set on enhancing muscle strength, you can consider adding strength training to your workout regimen. However, adding lots of muscle mass is generally not required or recommended for cyclists who want to minimize mass. If you want more explosive strength, you can add ballistics exercises, such as the jump squat or plyometrics. For explosive strength and enhanced aerobic endurance, add interval training to your bike routine. Regularly break into sprints, then return to your less-intense training pace.