Imagine this: You’re in the middle of a deadlift WOD. You’re smoking it, in your zone. Good form. Nice pace. You have your biomechanics and muscular activation down pat; you know exactly how to move and when to produce optimal efficiency. It has taken you a while to become this good at deadlifts, but moving the bar from the floor has now become second nature.
Then, all of a sudden, someone sneaks up behind you, reaches through your legs and — just as you ascend for another rep — pulls down on the bar. What would that action do to you, besides tick you off?
First, it would likely affect your biomechanics. That is, you would have to alter your form to accommodate that change in resistance. You may get pulled momentarily downward or the greater contraction of your hamstrings may affect the angles of your hips or knees. Second, you would need to respond by producing more force than you normally would at that point in the lift so that upward motion could be maintained. And third, you could possibly strain musculature or a joint because you’ve loaded muscles with an excessive stress, one you were neither positioned for nor expecting. You are simply not anatomically, neurologically or muscularly prepared for that stress at that point in the lift.
It’s not a scenario that you’re likely to encounter in real life, but that same cascade is what happens when you bounce bumper plates off the ground in any upward lift in a WOD for time.
Here’s a more likely scenario. An athlete is in the box, deadlifting a moderately heavy weight, perhaps 80 percent of one-rep max, for reps. In an effort to increase speed, she begins to bounce the plates off the ground. When the plates hit, they rebound, bouncing upward. This upward momentum reduces the amount of upward force the athlete needs to exert on the bar. To this point, all is good. That first inch off the ground is a breeze, but it doesn’t stay that way.
Depending on the type of rubber in the plates, the material of the floor and the speed of descent, the bounce-induced upward momentum will cease when the bar is roughly 1 to 3 inches off the ground. That’s around the point when the momentum of the bounce loses out to gravity and the bar slows. We will therefore call this phenomenon “bounce-induced deceleration.”
When the bar decelerates, it suddenly becomes functionally heavier. The weight is the same, but it feels heavier. Why? Because the athlete has lost the assistance of the upward momentum from the bounce, and she must make up for that loss by contributing more muscular force in order to continue the bar’s smooth ascent. It’s here that we see the effect of this phenomenon. With bounce-induced deceleration, it’s exceedingly difficult to maintain a smooth ascent. Just watch someone bouncing a heavy deadlift. The athlete appears to be jerked downward just after he comes off the ground — almost as if someone snuck up behind him and pulled the bar down.
There has been no real research to identify or quantify any risks involved with bouncing the weights off the floor, but in practice, we don’t recommend it, particularly for beginners, because neuromuscular learning and efficiency may be negatively altered and the potential for injury exists.
In the meantime, there is absolutely nothing wrong with a steady, solid touch-and-go technique.