Answer: One external force was the ground pushing into my foot as I ran. This is a compression force. Gravity is also an external force that is working to pull my body down toward the ground. Since I’m trying to move my body forward, gravity is probably hurting my performance. Since I lean slightly forward when I run, there is a small tension force in my lower back. There is also tension in my shoulders as my arms swing by my sides.
Explanation: EDMENTUM