Can Isometrics Help You Jump Higher?

Written by Jack Woodrup for VerticalJumping.com

Isometrics has been included in a number of jump programs including the Vertical Project and Athletic Advantage as a means of developing your muscular power. In this article we discuss what exactly they are and how they can be used to develop an athletes jumping ability.

What Are Isometrics?

Isometrics are static contractions. By static contractions we mean muscular contractions where the muscle is contracting without actually moving. An isometric contractions occurs any time you are holding a weight in a fixed position (a yielding isometric contraction) or pushing/puling against an immovable object (overcoming isometric contraction).

Technically speaking an isometric contraction also occurs in any vertical jump. It usually only happens for a bried moment in between when you go from descending to exploding up. That split second where you are not going up or down is also an isometric contraction.

How Isometrics Can Help You Jump

At first performing a static contraction might seem counter productive to the improvement of jumping ability. After all a vertical jump is a movement, not a hold. However further investigation shows there might be more to isometrics than meets the eye.

Vertical jump is an expression of muscular power. The equation of Power = Force/Time (or Force x Velocity). Force is highly correlated to strength. Strength is determined by size and number of muscle fibers recruited. And this is where isometrics comes in.

Isometric training forces your muscles to recruit more fibers. When you statically hold or maximally contract against a heavy or immovable weight, your body starts activating and recruiting extra fibers to maintain that hold or intensity. In other words your contractions start to become more neurologically efficient.

If you wanted to apply this knowledge to your vertical jump training you might try performing static maximal effort holds to teach your muscles to recruit more fibers. The more fibers you can activate the stronger you become.

So What's The Catch

The downside to isometrics is that the consequent neurological and strength enhancements are basically limited to the angle at which you are performing the hold. In other words isometric training with your knees bent at 90 degrees will help you get stronger at holds at that angle, but as you move through the range of movement, these strength gains diminish. In the example of a vertical jump you might descend into it by bending your knees to approximately 90 degrees, but as you explode up and away from that angle you start to lose the benefits.

To overcome this both Athletic Advantage and the Vertical Project recommend performing isometric contractions in a power rack across a number of different angles in the jump ranging from the bottom, to the half way point, to just before the top of the movement. The idea behind this is to train your body to recruit the extra fibers across the full range of the jumping motion.

Anything Else To Know

As you might have understood from the description of how isometrics are used in vertical jump training, the benefits are mainly limited to muscle recruitment. The majority of your time will still need to be spent performing traditional strength and power training using dynamic contractions.

Also on that note, traditional strength and power work, particularly with very heavy weights, will also effectively teach you to recruit more muscle fibers. Another observation of isometrics is that the strength gains made from this type of work often seem to stagnate after about 6-8 weeks.

A couple of closing thoughts is that there have been a number of studies actually done on isometrics and vertical jumping. One study done at Southern Cross University in Australia compared the training effects of heavy weights with functional isometric training on the development of strength and power.

The study showed that whilst both the isometrics and heavy weight groups showed improvements in strength, only the heavy weight training group also showed significant improvements in a counter movement jump.

Another study performed at Oregon State University compared regular barbell squatting to parallel versus functional isometrics. Both groups increased their strength but the dynamic squatting group improved their vertical jump power by DOUBLE that of the functional isometrics group.

Conclusion

Isometrics is not something that a lot of athletes and coaches use. In our experience there are two main reasons for this. The first is that other means of strength development such as traditional heavy and explosive weight training provide more tangible and quantifiable improvements. As a result athletes prefer to use these methods.

The second is that using traditional heavy weights across a full range of movement is quicker and easier because you do not need to keep stopping and resetting the bar height to train the different angles. This not only saves time but also ensures there are no gaps anywhere in your strength development across the range of the lift.

Both these points are very valid reasons for not using isometrics in your strength training. In summary we have to conclude that yes isometrics does indeed offer some benefits for athletes training purely for strength or shape, they offer less benefit to athletes training for the development of their vertical jumping ability than more traditional lifting techniques.