Only during wokouts that target the quads specifically like weighted squats. During regular running or walking, the hamstrings contract eccentricly to control the extension of the knee. Otherwise, the knee would would kick out in a snap with a powerful quad contraction. Esteban SPTA, South Texas College
The hamstrings must relax.
Muscles on one side of the joint have to relax in order for the muscles on the other side of the joint to contract. Example would be the quadriceps would have to relax and lengthen in order for the hamstrings to flex.
in the arm: bicep contracts (agonist) triceps relax (antagonist) in the leg: hamstrings contract (agonist) quadriceps relaxes (antagonist) remember the agonist is the muscle "agonising" to do the work - like pulling the joint.
Muscles on one side of the joint have to relax in order for the muscles on the other side of the joint to contract. Example would be the quadriceps would have to relax and lengthen in order for the hamstrings to flex.
Quadricepts
Reciprocal inhibition is the process by which muscles on one side of a joint relax allowing for the muscles on the other side of the joint to contract. It is a coordinated pattern an example of which would be when hamstrings relax so that the quadriceps may contract while running/walking and this occurs over and over. Type Ia sensory afferent axons project via inhibitory interneurons to the antagonistic muscle group (hamstrings in the case of walking) therefore inhibiting the hamstrings as the quadriceps are excited and vice versa.
When you Bend your Leg your hamstring contracts and your quadriceps relax
The antagonist muscle in the flexion of the knee is the quadriceps muscle group. When the knee is being flexed, the quadriceps relax to allow the hamstrings to contract and bring about the flexion movement.
the quadriceps will contract and the hamstring will relax .the quariceps straightens the knee and the hamstring extends the hip and bends the knee to kcik the football the quadriceps will contract and the hamstring will relax .the quariceps straightens the knee and the hamstring extends the hip and bends the knee to kcik the football the quadriceps will contract and the hamstring will relax .the quariceps straightens the knee and the hamstring extends the hip and bends the knee to kcik the football
Quadriceps
To raise your foot, your leg muscles, particularly the quadriceps, hamstrings, and calf muscles, must contract. The quadriceps lift the leg up at the knee, the hamstrings help with hip extension, and the calf muscles assist with pointing the foot.
It is 3/2