Hello Physics Gurus, Please critique the following logic... When a runner hikes/runs to the top of a mountain, the chemical potential energy inside the muscles transferred into the potential energy of the runner's body mass at the higher elevation (Pe = mass*gravity*height = mgh). Energy is also transferred into the heat of the muscles, the breakage of chemical bonds in the muscle, and friction losses on the ground. When a runner now runs DOWN the hill. The potential energy of the body being at a high altitude is lost. With each step, the runner is transferring the potential energy into the heating and tearing of their muscles. Some energy is also lost to friction effects from the shoe on the ground and air resistance. The effect of this potential loss is significantly more damage to the muscle, because the potential energy has to be absorbed by the body. Conclusion: running uphill depletes the energy stores in your muscles more than running downhill. Running downhill does more muscular-skeletal damage because the potential drain is absorbed by tearing and heating muscles. Is this reasoning correct? Am I missing something? Is my conclusion that the potential is absorbed by damaging the muscles correct? Thank you!