Tuesday, November 11, 2008
Med Ball Throws and Box Jumps
Nothing incredibly fascinating about this but perhaps a couple of things are noteworthy:
1. The acceleration of the body (trunk/torso specifically) into the legs, driven by the arm and shoulder drive, is of primary importance to loading the legs properly on the med ball throws and the box jumps. Often an athlete will attempt to over control their torso and resist the drop limiting the elastic energy stored in the legs. This is a mistake! Every action produces an equal and opposite reaction so a faster downward movement of the torso (the action) increases the speed/power of the jump (the reaction). This is pivotal as it is very difficult to rapidly accelerate, and therefore jump high, if the athlete has not loaded their spring (their legs and trunk) properly.
2. On the box jumps, the critical factor is hip height. Many believe that a 42" box jump is equivalent to a 42" vertical jump but this is simply not true. It's the change in center of mass, at the hips, that indicates true jump performance. This jump specifically is probably in the range of 32 to 34". A good rule of thumb is to jump and land in the same position and this goes way back to Coach Jimmy Radcliffe at the University of Oregon. Landing in too deep of a squat position, as I am guilty of in my chase for a 52" box jump, should not be encouraged in training. It is still a reasonable display of athleticism but not a practice common to great training programs where the best interests of the athlete, and not of puffed up box jump or other performance numbers, are the focus.
A good guideline for selecting box jump height is not to go beyond a 10-20% difference than the athlete's best vertical jump. So for an athlete who jumps 20" high, a 20", 22" (10%), or 24" (20%) box is appropriate.
3. There is nothing magical about box jumping. Jumping onto a box is not a secret to superior sports performance. Jumping onto a box simply saves the athletes legs from landings. So considering good quality jump performance the only difference between jumping over a 42" hurdle and jumping onto a 42" box is the height of the landing. I will often have a box at about 50% of the height of the box we are jumping for the athlete to step down onto to save the legs.
As you can see I'm quite the rebel and do not step down onto another box. But you can see that I do pay attention to how I am landing. It's not the fall that kills ya, it's the landing!
3. Look at the foot/ankle mechanics closely on the med ball throws and box jumps. The ankle stays relatively neutral, and to a certain extent the foot is not loaded properly and the ankle resists any dorsiflexion which will limit successful toe off on the jump. This same toe off is critical to great sprinting and jumping as this represents the last link in the kinetic chain. This is a relatively minor detail but when the difference between 1st and 2nd place is often percentage points on percentage points we owe it to the athlete to look everywhere for improvements. In this case, I am the athlete demonstrating and outside of box jumps and med ball throws I am not focused on these improvements although I will certainly address them in my training. My primary focus is improvement on the snatch and clean and jerk movements from olympic weightlifting. Keeping things in context is important as well for this is no reason to focus on one detail that will give you a percentage point on a percentage point when there may be other details (in my case maximum strength, olympic weightlifting technique, and bodyweight) that will give you ten points.
4. This is really an aside but this kind of thing is common in my thinking so deal with it: Any coach training athletes should have athletes capable of performing any portion of their training program at a high level. I can't stand things that my athletes cannot do well. Whether it's a coaching limitation or an athlete limitation, if I can't correct the skill and improve the athlete's proficiency in said skill then I either need to move back in the progression or focus on something else entirely until training such a skill is more appropriate. I'm demonstrating the med ball throws and box jumps here because I don't video a lot of my athletes training and haven't asked permission to use the video I do have (although I will certainly do so in the future). Video allows for a different kind of feedback and with so many athletes learning and developing in so many different ways more feedback is almost always better than less (although there are reasons to reduce external feedback as well but more on that later).
Big shout out to Coach Turner at Vanderbilt University Strength and Conditioning. Super bright coach focused on the best interests of the athletes in his care. Thanks for the shirt!