May 5, 2019
it's important to understand that hip flexion is a primary motion of the leg. And it sometimes needs to be done very forcefully or quickly. If you walk then you engage in hip flexion often and if you participate in any recreational athletics then chances are you perform hip flexion quite forcefully and with some rapid succession. The best example I can think of is running or sprinting. Think of how many times you lift your thigh or bring it forward quite quickly.