I'm looking at a situation where a sprinter starts at some distance x from a wall. The goal is to sprint to the wall, hit it, and get back to the start as quickly as possible. There are two ways which this can be accomplished:

  1. Run to the wall, take a slight leap and plant one foot on the wall. Push off the wall, and turn around as you do. Once you've returned to the ground, which should be approx no more half a meter from the wall, begin sprinting back.

  2. Run to the wall, jump at it and turn around in the air to plant both feet on the wall (you are now somewhat parallel to the ground and "sticking" to the wall, in what might as well be a squat position). Jump forward from the wall (you should land farther than in the first case) and begin sprinting back.

If clarification is needed, please say so.

Assuming someone has the strength and capability to do this easily, from a Physics standpoint, which would be the quicker alternative? My gut is telling me the later because of the higher force you can get from using 2 feet (resulting from being able to more easily use all your weight), therefore you have a higher velocity when hitting the ground. However, a friend is going with the former due to leverage advantages.

  • 1
    $\begingroup$ This is very hard to answer as it involves knowledge about the biophysical aspects of your legs, maximum acceleration, strength, "spring" constants of your muscles, etc. Assuming a lot of strength the 2nd approach would most likely be faster as you can push with both legs against the wall. In practice the 1st will probably be faster as it is a smoother movement. $\endgroup$
    – Alexander
    Nov 14, 2011 at 17:32
  • $\begingroup$ This seems more like physiology than physics. $\endgroup$
    – FrankH
    Nov 14, 2011 at 17:34
  • $\begingroup$ i'm not getting the difference!! in the former case you have one leg at the wall while in the latter you have both the legs which acts as a spring!!!Am I correct?? $\endgroup$ Nov 14, 2011 at 18:23
  • $\begingroup$ @Vineet - Correct. In addition, in the two-legged case, you are turned around as you approach the wall where in the one-legged case, you are turned around as you leave the wall. $\endgroup$
    – MGZero
    Nov 14, 2011 at 18:54
  • $\begingroup$ @Alexander - What exactly do you mean by a smoother movement? $\endgroup$
    – MGZero
    Nov 14, 2011 at 18:55


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