The myths about plyometrics
Understanding the entire picture
Allison Hamilos posted an arti cle about plyometrics on March 20, 2012. Although she gave the right reasons for doing plyometrics, what she considered plyometrics is quite inaccurate and would not improve your goals of explosive strength. What she described can be usable in its own right as a fat-loss and general conditioning workout, but it is not true that it would help you jump higher or run faster (assuming that you are already a decent athlete). Her safety advice is sound, other than the use of “athletic shoes.”
When doing plyometrics, you should be barefoot or wear shoes with very thin soles (Vibram FiveFingers, Converse Chuck Taylor, Saucony Kinvara, Nike Free, etc). A main muscle group you train in plyometrics is your foot, so if you cover it up too much with modern “athletic” footwear, you are not going to get the results you want. Also, since you want to really focus on landing at your mid-foot and getting off the floor as fast as possible, the cushions in most shoes would only slow you down and reinforce improper motor patterns. Basically, plyometrics work primarily through stiffening your feet and ankles, allowing you to pop up off the floor in less time, decreasing the amount of kinetic energy you transfer into the floor rather than propelling you up. In general, just be careful when you land and don’t act a fool. Using “athletic shoes” breeds improper form, carelessness, and they really don’t absorb enough energy to save your joints from a bad fall. Please consult a doctor before beginning plyometrics or if you run into painful issues.
Myth #1: Speed is not dependent on strength
Although this may seem like a strange introduction to plyometrics, it is fundamental to understand the relationship between speed and strength to understand what plyometrics is. Strength is the amount of work you can do without time constraint. Speed is power: how fast you can apply your strength.
Let’s assume that all three athletes are the same height and weight:
|
|
Max force of half squat without time constraint (2 seconds) |
Max force applied out of a vertical jump (0.2 seconds) |
Reactivity ratio |
Strength ranking |
Speed ranking |
Reactivity ranking |
|
Athlete A |
250 lbs |
200 lbs |
80% |
3 |
2 |
1 |
|
Athlete B |
500 lbs |
190 lbs |
38% |
1 |
3 |
3 |
|
Athlete C |
500 lbs |
400 lbs |
80% |
1 |
1 |
1 |
In this case, Athletes A and C are equally reactive, but Athlete C is much faster and stronger. Athlete B is very unreactive, but because he is so strong, he is barely slower than Athlete A. Plyometric training can improve the reactivity ratio, but it cannot increase strength. Since Athletes A and C are already at a very high reactivity ratio, plyometrics would be ineffective for them. Instead, they should focus on gaining strength if they want to get any faster. Athlete B, on the other hand, should get on a plyometrics program to improve his reactivity ratio.
If your strength level is low, you should not care about reactivity ratio and just focus on getting stronger. The average inactive person actually has a higher type II-b fast-twitch muscle fiber ratio than the average athlete in a sport that involves endurance. Reactivity is also much more difficult to improve than strength. Also, without developed muscles, chance of joint injury is high. After a few months of a pure strength training program with no jumping, I was able to get from a standing vertical of 23 inches to 27 inches, even though I probably lost reactivity. After a month of reactive training to take advantage of my new found strength, I was able to get to 30+ inches. For reference, the average NBA player’s vertical is only 28 inches.
Myth #2: Plyometrics workouts should be exhausting
The purpose of plyometrics is to improve pure speed and explosiveness, so any program with an endurance component does not develop plyometric ability. Immediately available ATP can only last about three seconds. After that you are switched to the phosphagen system, which might last you another 15 seconds if you are focused and took creatine. After that, anaerobic exercise cannot continue and you will end up using mostly type I slow-twitch muscle fibers. A set that lasts 30 seconds with only a minute of rest would not provide any benefits to speed.
Instead, you should do plyometrics sparely, but highly focused. A program for increasing vertical jump would look something like this:
1. Dynamic warmup with focus on shoulder and hip mobility
2. Depth jumps: three sets of four reps. Take your time between each rep and rest at least two minutes between each set. You should be extremely concentrated on each rep and explode as fast off the ground as you can. The sets might be mentally exhausting, but should not feel physically tiring at all.
3. Jump squats: three sets of six reps. Use 25 percent of your squat max. You should explode up immediately after each rep. Rest at least two minutes in between.
4. Squats: Warmup from bar, adding weight each set up until working sets. Four working sets of six reps at 70 percent of max. Rest at least three minutes in between.
5. Half Squats: three sets of eight reps. Use the same weight and rest time as squats.
6. Leg curls: three sets of 10 reps.
7. Back extensions: four sets of 12 reps.
If you wish to learn more about plyometrics, I encourage you to read The Vertical Jump Development Bible by Kelly Baggett.