Pedaling a bike causes eccentric and concentric contractions in your calf muscles.
Strength training exercises are isotonic exercises, which means that the amount of tension placed on a particular muscle during an exercise remains constant, but the length of the muscle changes. During an isotonic exercise, your muscles experience both eccentric and and concentric contractions as they lower and lift a weight. The calf raise is an isotonic strength training exercise, which means it is both concentric and eccentric.
Calf raises are both concentric, while you are raising up, and eccentric, while you are lowering back down.
Raise it Up
During a calf raise, you rise up on your toes against added resistance. As you rise up on your toes, your calf muscles shorten into a concentric contraction. This brings the insertion and origin points of the muscles closer together, moving your bones in the process. This lever action allows you to lift objects such as weight. During a strength training exercise, this is the portion of the exercise that is most difficult since your muscles have to work hard to lift whatever weight you are using.
Lower Back Down
The next phase in a strength training exercise is the eccentric contraction. During a calf raise exercise, your heels drop down and your muscle lengthens into an eccentric contraction. In an eccentric contraction, the insertion and origins move further apart allowing you to lower the weight. A common misconception is that your muscle is resting at this point. This part of a strength training exercise certainly feels easier than the lifting phase, but your muscle is still working to lower the weight. It feels easier because your muscles are stronger during an eccentric contraction.
Find Your Tempo
If your goal is to build muscle strength and size with the calf raise and other strength training exercises, there are some techniques you should follow to get the most bang for your workout buck. The American Council on Exercise says the speed at which you perform your reps has a direct affect on your results. During an isotonic exercise such as the calf raise, the concentric, or lifting phase, of the movement should be performed in two to three seconds. When lowering the weight, ACE says you should slow down slightly and take three to four seconds to lower the weight.
Try Some Negatives
Take advantage of the strength you have during an eccentric contraction of your calf raises by applying a technique known as negative sets. Negative sets are a useful tool to add variety to your workouts or to break through a training plateau. This advanced training technique should not be done by beginners. To perform negative sets, set your weight for an exercise heavier than usual. Have a training partner help you with the lifting, or concentric phase, of the movement and then let you lower the weight through the eccentric phase on your own. Lower the weight slowly and with control. This technique can help you to build strength by challenging your muscles more during the eccentric phase that you would normally be able to.