JL is sitting in a chair wearing very heavy boots. She slowly straightens her leg, raising her boot.
4. Is this an isotonic or isometric contraction?
5. Name the prime mover and antagonist participating in this action. and discuss the mechanics of this action, naming the class of lever and the names and relative positions of the fulcrum, resistance, and effort.
4Q).
The isotonic exercise involves muscle shortening against a constant load. During the isotonic type of contraction, the length of the fiber changes but the muscle tension remains constant. For example, simple flexion of arm involves isotonic contraction.
In the isometric type of contraction, the muscle length remains constant but the muscle tension increases. During isometric exercises, the person relaxes initially, and then contract the muscles, while keeping the body in a fixed position (i.e. without moving the body).
Slowly straightens her leg, raising her boot involves the isotonic muscle contractions.
5Q).
The prime mover participating in this action is, quadriceps and the antagonist is, hamstrings.
The given movement involves a third-class lever. In third class levers, the pull is exerted in between the load or resistance. The muscle insertion is often close to the joint it moves. They are the most common type of lever system in the body and allow free and rapid movement.
Resistance – Weight of the boot
Fulcrum – Knee joint
Effort – Quadriceps femoris of the thigh
JL is sitting in a chair wearing very heavy boots. She slowly straightens her leg, raising...