Daniel Andrews made me think about acceleration with his focus on how the body generates ate of change of velocity with time, and his use of delta was very appropriate. Currently sled work is used to create a good workout and it’s a lot of fun. I have pushed a prowler, pulled weight for sled drags, but never timed my 10m dash as I know it will not transfer. The ironic thing about heavy sleds is that acceleration doesn’t really happen overall during the pushing distance, save the first few steps. Once the athlete is going, the acceleration peaks early and is sustained at a slow walking pace. Many American coaches claim that this works the muscles of acceleration (legs), and I agree it does. It does provide a nice overload. Cleans, plyos, and squats don’t work the muscles of the legs for acceleration? Posture? Most team sports don’t have the postures I see with sled pushing, and if you are truly accelerating, your posture rises to vertical along with changes in foot strike. What are we training really?
Notice that everyone that does push the sled looks like the same person that would be building pyramids. If we are coaching where is the technique improvements? Arms are always in a extended position in front. This is why I like pulling a sled by sprinting and accelerating, not pushing a heavy sled slow at the same speed. I want my athletes to shift gears, not move slow on a riding lawn mower.
Another myth is hip hyperextension or Super Triple Extension. I am not familiar with those terms in text books, but coaches have the right to create new terms based on observation. Most acceleration postures have a straight line from ear to ankle. With bent over postures, this angle is more pelvis based, but I don’t see anything additional to 180 degrees unless you are doing a mule kick in the air. If you are not touching the ground, no contribution to speed is happening. While the picture has a lesser angle than 180 and is wrong, the point was to show additional range would be impossible unless the person was doing a glute master exercise.
Hopefully I sparked a few questions with sled use. I think that large athletes such as lineman and linebackers can help with some functional pushing, but using it for a combine isn’t going to make a dramatic improvement in 20m acceleration.