Hi there: The other day I had a session with a number of younger athletes. And we were working on some plyometrics. But plyometrics are a funny thing. Because what we normally think of as a plyometric is a much narrower inclusion of all the movements we perform during the day which actually are plyometric.

Plyometrics are based on something called the stretch-shortening cycle. A muscle is first lengthened followed by a transition phase and finally by a muscle shortening phase. So walking in effect is a plyometric activity although the extent of lengthening and shortening are reduced and the transition phase in the middle is greatly increased.

What we more commonly recognize as plyos would be hurdle jumps or explosive push ups. And while for many the goal right out of the gate is to be as fast and get as high as possible there are a couple of other things to consider to get the most out of your plyometric training.

The first thing to consider is that you have proper joint alignment and angles. This is important for two reasons. For one it ensures that the force from ground impact is transferred and dissipated efficiently through the appropriate muscles and joints. As a result you help minimize the potential for injury. Another good reason for proper alignment is that you ensure that you get the best return on your effort. Take a look at the cartoon below.

In the cartoon the door doesn’t open if you push instead of pull the door open. And if it was a door that pushes in order to open we’d get the best result by pushing directly into the door and as far from the hinge as possible. If we push sideways or close to the hinge we don’t get the result of the door opening.

If we don’t align the body properly for a plyometric effort we will not get a very good response from our efforts. Worse we could end up hurting ourselves. For example on a jump we want our efforts to be directed straight down into the ground so that the resulting push back is vertical. If there is any type of deviation from a neutral position we see some of the energy being directed into the ground and some being directed into the joint. Consider the images below.

In the image on the left we see ground contact where the knees line up over the feet. The image on the right shows a situation where the knees moved inward.

Obviously in the scenario on the right we aren’t getting a very good propulsion up if this image demonstrates the take off. While some of the force the athlete is generating is vertical and into the ground, some of the force is also being directed laterally and is thus wasted energy if the goal is get up as quickly and as high as possible.

More importantly however is the  concern of if these images represent a landing. Very few athletes get hurt on take off from plyos. If they do suffer an injury from this type of training it is almost always upon landing.

And we can see why. With the image on the right some of the force of landing is reduced and dissipated muscularly. However as a result of the inward position of the knees some of the vertical force of the landing will be directed to the inside of the knees and thus put strain on the associated connective tissues such as the ACL and meniscus.

As you continue on with your plyometric training keep two things in mind. The first is to ensure you have neutral alignment through the lower extremities. And secondly make sure your focus and effort is on the landings. Make them as quiet and as controlled as possible.


Leave a Reply