Wednesday, April 24, 2013

The Power of Plyometrics

Plyometrics. Plyos. Today I want to talk about plyos.

I love plyometrics. I always have. Plyos highlight one of my main fascinations with the human body; the specificity with which it reacts to training stimuli. When you're doing plyos correctly, you're not training your muscles in the traditional sense. You are specifically training a reflex. That's right. You are intentionally sensitizing and desensitizing a set of neurological patterns, the end result of which is that you become more explosive. It let's you jump higher and hit harder without actually adding a significant amount of muscle mass. Plus, you get to jump around and throw sh*t which is highly entertaining. 

First of all, there seems to be some confusion amongst the general public about what 'plyometric' means. You ask most people in the gym and they'll say, "jumping." This isn't wrong but it's not exactly right either. Almost all plyometric exercises for the lower body involve jumping of some kind but there are also exercises that involve jumping that aren't plyometric.  Time for a quick physiology lesson.

Inside our muscles we have sensory receptors called muscle spindles. When your muscle is stretched to a certain point, these muscle spindles pick up on it. They initiate the "stretch reflex" which causes the muscle to contract and shorten. This series of physiological events is referred to as the stretch shortening cycle. Brilliant, I know.

There are basically two things in our musculo-skeletal system capable of doing mechanical work. One of them is your muscles, which generate mechanical energy through contraction. In addition to the muscles themselves your tendons are also capable of doing a small amount of work. While they don't technically contract they are capable of storing mechanical energy when stretched, sort of like a rubber band, and this energy can be used if the muscle is contracted fast enough after the initial stretch. The elastic energy dissipates fairly quickly under constant tension. 

Plyometrics increase your muscles' ability to produce force by training these two very specific components of your physiology. So, what then is a plyometric exercise? A plyometric exercise is one that trains the sensitization of the stretch reflex and increases the strength of the "series elastic component" (translation:stretchy stuff) of your muscles. 

What does that mean for you? Well, that really depends on what it is you're trying to do. Specificity, remember? Plyometrics are great for increasing explosiveness in athletes and particularly in increasing vertical jump height. They've also been shown to be effective in strengthening the musculotendinous junction, which has both rehabilitative and preventative implications. This is likely due to the large eccentric component of any jumping exercise. 

If you want to incorporate plyos into your routine because you want to jump higher, further safeguard your joints or just for something new to try, here's how. 
General guideline for plyometrics is 25-40 ground contacts per session. For all intensive purposes, a ground contact is a repetition. Research suggests that you get the most benefit from plyos performed at the end of a training session. The mechanism has been attributed to increased motor neuron recruitment/ post activation potentiation, but last I checked they still weren't exactly sure why this was the case. All I would say is make sure you are thoroughly warmed up before doing any plyometric exercise. In terms of volume per week the guideline is 100 or fewer ground contacts per week for a beginner, 125 for a moderate athlete and 140 for an advanced athlete. These can be broken down any number of ways but you should avoid doing plyometrics more than two days in a row and more than four days a week. 

In addition, in order for all exercises to be TRULY plyometric the idea is to perform them as quickly as possible after the eccentric (lowering) phase. In other words, jump as fast and hard as you can after hitting the ground. Also, try to land a ninja. This way you ensure you're absorbing the impact properly which means you can use more of the stored energy and you're preventing damage to your joints. 

Sample Plyometric Workout: (these are all designed to be added at the end of a workout)

Day 1
Depth Jumps 3x5
Drop Jumps 2x5
Skater hops 3x5 (each leg)

Day 2
Box Hops 4x6

Day 3
Single Leg Hopping 4x5 each leg
Lateral Hurdle Jumps 3x6 

Just be careful. I encourage everyone to try them out but you should have a solid base of fitness before you do any plyometrics. They are a really good way to hurt yourself if you do them incorrectly. Now get out there and go jump over some sh*t. 


Today's Workout:

Jump Rope/Dynamic Warm-up - 15 min.

Power clean

3-3-2-2-2-1-1-1-1 135,145,155,165,175,185,195,195,195


145 3 reps every minute on the minute 5 min

Jumps Rope/Dynamic Warm-up - 15 min

Crossfit Hero WOD from 4/23
Run 800 meters
then two rounds of:
50 burpees
40 pull ups
30 one legged squats
20 kettlebell swings (1.5 pood)
10 handstand push ups
then run 800 meters

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