Vertical leap training using bands as an aid can be VERY effective, but they have to be used correctly. This article isn’t about how to use bands, but it us to clarify a misconception about one technique for using bands in conjunction with isometric training as well as clear up some physics of how band training stresses the muscular system.
What Is An Isometric Contraction?
An isometric contraction is one where the muscle stays the same length as resistance is placed upon it. This is like pushing a wall, where you don’t move, and either does the wall but resistance is applied throughout. Isometric contractions can be useful as the teach a specific position to recruit a maximal number of muscle fibers. As the muscle fatigues and muscle fibers reach “failure” other muscle fibers are recruited to maintain the muscle tension.Some believe that an isometric contraction caused by an elastic band causes your muscles to pull “faster.”
The theory goes… Elastic bands when stretched and released travel faster than the pull of gravity. Thus their pull on the muscle elicits a contraction speed which is also greater then the speed of gravity.
Seems logical right?
Unfortunately it’s not quite science. The truth is band tensions has an equivalent in poundage. This means that you could stress a scale with 50 pounds of elastic band force or 50 pounds of bricks (gravitational pull) and the scale OR your muscles only feel 50 pounds. Your muscles wouldn’t be aware of that there was great kinetic energy in the elasticity of the band. The 50 pounds IN ISOMETRIC HOLD would feel EXACTLY the same.
Basically if we put a bar on your shoulder and one had 100 pounds of weight, it would feel identical to the strain of 100 pounds of band pressure… if it was an isometric hold.
So what is the difference in muscular tensions when training with elastic bands? It feels different!
If you have ever trained with bands you know it feels different. It feels as if the bands are pulling you FASTER!
What is actually going on is the bands “stick” the resistance to you and you can’t escape the constant force of it’s pressure.
You see, with “dead” weight if you move down quickly the weight will actually become lighter as the inertia of your body and the weight equalize. When they go down at similar speeds there is LESS muscular tension.
Bands are different. Bands pull faster than gravity, so your body moving quickly will not have a lightening affect on the load the elastic bands are charging onto your back. Muscular activation during an eccentric contraction is very intense as your muscle must remain in control and in constant tensions during the full range of motion.SUMMARY:
Band tensions during an isometric hold has an equivalent in “dead weight” poundage and does not make your muscle pull “faster” during an isometric hold. Band poundage recruit muscle fibers equally (in accordance with tensions poundage) during an isometric hold. Bands tensions is unaffected by gravity when during an eccentric movement, and thus the weight will not lighten (other than a slacking of band tension). This is why bands feel as if they are pulling you “faster,” when really the band tensions simply can’t be escaped or lightened as a “dead” load could be. Bands rock, and provide accentuated eccentrics, and progressive resistance during the concentric phase.Since we are talking about elastic bands check out this insane rubber band gun… random.