Calf Isometrics may be one of the easiest ways to improve strength in the foot and ankle since it can be accomplished with no equipment. Developing tendon strength is one of the best ways to prevent overuse injuries. It’s been shown that world-class sprinters have a much stiffer lower leg than do amateurs. Developing isometric strength through the muscles of the foot and ankle helps reduce ground contact time, and increases elasticity and running economy. Muscle stiffness can significantly improve the efficiency of long-distance runners.

My own work with calf isometrics began 4 years ago. I began reading and researching the spring ankle theory by strength coach Cal Dietz and track coach Chris Korfist. I started using their techniques and training protocols and have adapted them over time.
  By increasing the duration of the isometric holds in various knee positions, has been shown to increase tendon strength. This is important for distance runners as this is often the site of overuse tendon-based injuries. Once an athlete is able to hold an isometric contraction for approximately 60 seconds in each of the 5 different positions outlined ahead. It is time to start having external loads.

External weight or load can be added in several different ways. The athlete can hold a dumbbell, use a weighted vest or belt, or use a safety squat bar. All these allow the athlete to hold on to stabilize the body, and not have to be concerned with balance.

There are 5 different positions that are used for calf isometrics. There is a 90° bend at the knee that is in a low angle position and a high ankle position (this is close to a time trial position), a 45° low angle position and high ankle position (similar to a run stance phase) and a straight leg with a high position only this gives us 5 different positions and will be doing each leg individually so gives us 10 total sets. 

The calf isometric positions can easily be built into any strength plan. As they do not take up a lot of time. They can be paired with other exercises fairly easily. Calf isometric complement well with the Toe Pro exercises. I do not recommend doing both on the same day. Calf isometrics work well on strength days and the Toe Pro exercises can be used on alternate days.

One of the most effective ways to improve tendon flexibility is by doing isometrics at the midpoint of the range of motion. In the case of the Achilles tendon, we would go to the halfway point between a calf stretch in the high range. The athlete would complete a 5-second isometric contraction on each leg followed by a 10-second calf stretch on each leg. This be performed for 3 sets, and should be done prior to run workouts. Is been shown that he can significantly improve tendon strength through isometric contractions.

In the next lesson, I’ll demonstrate and explain the different calf isometric positions and their variations.