You know it and hear it all the time, but the body is a KINETIC CHAIN. Movement at one end of the chain affects the other. And more importantly dysfunctions, weaknesses, and asymmetries at one area in the body can have a devastating impact both PROXIMALLY and DISTALLY at other regions/joints of the body.
Here I am demonstrating how just the movement at my foot (eg pronation and supination) travels UP THE KINETIC CHAIN and consequently affects movement at my hips (eg internal rotation/adduction and external rotation/abduction). This can also occur VICE-VERSA - where movement at my hips cause movement in my feet. This linking of the kinetic chain has such a HUGE IMPACT on pathology and injury. For example, weakness of the glutes can result in hip internal rotation/adduction, which then consequently moves the knee into a VALGUS position - which is the knee position associated with a non-contact ACL or MCL injury. This is why if you are rehabbing from an ACL/MCL surgery, your physical therapist will be focused on HIP STRENGTHENING, even though it was your knee that was injured!
Physical therapists are THE MOVEMENT SPECIALISTS. Go see your local physical therapist today who will help you identify faulty movement mechanics and get you on a PREHAB routine NOW to decrease your risk for future injury.