In science, mechanical energy is the sum of potential energy and kinetic energy. It is the energy associated with the motion and position of an object.The law of conservation of mechanical energy states that in an isolated system that is only subject to conservative forces the mechanical energy is constant.n science, mechanical energy is the sum of potential energy and kinetic energy. It is the energy associated with the motion and position of an object.
As with the standing shin stretch, the cross-over stretch is well-suited for pre- and post-running stretching. You can perform this stretch with or without shoes. Start standing with your feet together. Cross your right leg in front of your left leg and place the tops of your pointed right toes on the ground.
If you feel tight or a muscle cramp coming on during the run, it's fine to stop and stretch. The best time to stretch is at the end of your run. Here are some basic tips for your stretches: 1  Don't bounce while stretching. Hold still on each stretch for 15 to 30 seconds.  Don't stretch through pain.