where do you hit the knee for reflex
Patellar reflex Striking the patellar tendon with a reflex hammer just below the patella stretches the muscle spindle in the quadriceps muscle. This produces a signal which travels back to the spinal cord and synapses (without interneurons) at the level of L3 in the spinal cord, completely independent of higher centres. From there, an alpha motor neuron conducts an efferent impulse back to the quadriceps femoris muscle, triggering contraction. This contraction, coordinated with the relaxation of the antagonistic flexor hamstring muscle causes the leg to kick. This is a reflex of proprioception which helps maintain posture and balance, allowing to keep one's balance with little effort or conscious thought.
Holder (gridiron football) In American football and Canadian football, the holder is the player who receives the snap from the long snapper during field goal or extra point attempts made by the placekicker. The holder is set on one knee five yards behind the line-of-scrimmage. Before the play begins he places the hand which is closest to the place kicker on the ground in a location designated by the kickers foot (In high school games, the holder/kicker combo is responsible for a kicking block, which lifts the ball off the turf), with his forward hand ready to receive the snap. After receiving the snap, the holder will place the football on the turf, or block, ideally with the laces facing the uprights and the ball accurately placed where the back hand was initially, then balancing the ball with one or two fingers until the ball is kicked.