Rectus Femoris
The brachiocephalicus muscle extends the head and neck. It also pulls the front leg forward.
Adductor magnus
Most muscles in the body have "counterparts", one pulls and your leg curls up, the other pulls and the leg straightens. They would be on opposite sides of your leg. The "biceps" are the upper arm top muscle, and the tri-ceps (I think) is the upper arm bottom muscle. They work in conjunction to let you 'curl a barbell'' or do a chin-up.
Rhomboid Major
ur hamstring and iwould get it checked out if it popped
The force that pulls things forward is called "thrust."
When a muscle contracts, it pulls with a force generated by the muscle fibers contracting and shortening.
The primary muscle responsible for moving the scapula forward and downward is the serratus anterior. This muscle originates along the upper eight or nine ribs and inserts along the inner border of the scapula. Contraction of the serratus anterior pulls the scapula forward and downward along the ribcage.
it hurts
Maybe the dog is fustrated
It's difficult to lose fat in targeted areas. One way to increase fat loss in your legs is to perform weight-bearing exercises. This will decrease the fat in your legs while increasing muscle. Leg lifts, squats, pushes and pulls are all good leg exercises to increase muscle and burn fat.
an erection