Multiple shoulder injuries and surgeries in shoulders and scapula region along with compressed c6 c7 vertabret that I've had treatment for have left my range of motion to hold a squat bar extremely uncomfortable, along with numerous broken foot injuries and ankles adversely affecting my knees have left me unable to do squats very well . So I gotta say I'm great full for the sled to strengthen my legs and build muscle so hopefully someday I can get back under the bar and get my squat on.