# What is the appropriate device for measuring energy loss from collision with surface?

The surface of a running track (i.e. cinder or rubber) has an effect on a runner's performance. I would like to get some device for measuring how much energy a runner loses on each surfaces. I've tried to rig up a system with a ball and measuring how high it bounces on both surfaces, but this hasn't worked out well.

Is there a device I could get that I get which would measure how much energy is lost when a body strikes a surface which would work on a cinder and rubberized surface?

• Can you elaborate a bit on why your bouncing-ball apparatus is failing to give a measurement? Feb 8 '14 at 23:18
• Is there a reason why the Coefficient of Restitution is inapplicable? en.wikipedia.org/wiki/Coefficient_of_restitution Jul 16 '14 at 12:01
• The closer the bounce height ratio is to one, the closer the collision is to elastic and the less energy is lost during the impact ($C_R=\sqrt(h_2/h_1)$). All you need to do is use the the vertical velocity of the runner's foot and the foot's mass to estimate the kinetic energy, then multiply by (Cr)^2. Jul 16 '14 at 12:07