I am going with a short rant today. It pertains to box jumps.
A box jump is a plyometric exercise that is often used to develop lower body power. They have many variations and are easy to implement.
This exercise is a mostly vertical jump with a landing on a solid surface. Different box heights can be used for different ability levels. It is a simple process of starting by jumping to a low box and work your way up.
The power development in the lower body is developed through the stretch shortening cycle and a forceful triple extension. The hips, knees, and ankles use the stored up energy from a pre stretch to propel the body up in the air. It is one of the most basic ways to safely train for power.
The body uses this opportunity to produce as much power as it can in the effort. All of the energy should be going to developing force in the lower body.
Good mechanics of a box jump include starting and landing in the same position. The position is similar to ¼ squats with a more pronounced hip hinge. The arms will go back and quickly come forward to launch into that triple extension.
Good landing mechanics include a chest up position, both feet on the box, little to no noise, and that athletic stance to brace what little impact is created.
Now everything I just laid out is not specific to the box jump (except landing on a box). The same guidelines stand for vertical jumps or broad jumps from and to the ground. So why are box jumps so special?
Its All About the Impact
They are a great plyometric exercise because they take the impact out of the lower body. When you land on a box, you avoid all of the eccentric stress caused by a landing on the ground. This is important to save the joints of the lower body.
Power training usually beats the crap out of the body because they involve high impact exercises. They also require the nervous system to adapt and grow, which takes seven times longer than the muscular system to recover.
Enter the box to at least reduce the physical demands of the exercise.
Herein lies the problem- Jumping off of the box.
The purpose of the box jump is to reduce impact on the landing. Jumping off of the box just adds all of that impact back in and then some. Jumping off of the box means you have to brace a landing that was higher than your jump from the ground.
You might as well just be jumping straight in the air and landing where you started.
Choosing the do box jumps is a great idea to improve lower body power. When done correctly they are a very safe choice. The jumper must step down off of the box or else there is no point in doing the box jumps.
It also uses energy and muscle action to jump down. If you are not putting maximal force production into the jump then why are you doing box jumps to begin with? Do they look cool/fun? Not the best reason to choose an exercise.
I also do not believe that box jumps should be performed as conditioning. There are better, safer, and easier ways to make someone tired or fatigued than using box jumps. Also, I am not a proponent of high risk exercises being performed in a fatigued state.
Back to the original purpose of this post; if you do box jumps, do not jump off of the box. If you insist on jumping down, then you really do not need the box in the first place. Use the box jumps for their intended purpose of a low impact option to develop power.
When we take exercises out of their original designs, the risk of injury increases while the exercise’s effectiveness decreases. Stick to the purpose of the exercise.