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Simon Gama
IN the last few years attention has been focused on the hamstrings, the muscle group located on the back of the thigh. However, the main exercise to develop this group is the lying leg curl, which is now under fire since it can place substantial stress on the knee joint. Another effective exercise for developing the hamstrings without this stress is the standing leg curl, in which the knee is not locked into place.
Major muscles involved
The hamstring group is composed of the semimembranosus, semitendinosus and biceps femoris, which has two heads at upper end. The long head is attached to the tuberosity of the ischium bone of the pelvic girdle, the short head to the middle and central area of the femur bone of the thigh. At the lower end, the biceps femoris inserts on the lateral condyle of the tibia and head of the fibula bones. The tendon of insertion forms the lateral hamstring.
The semitendinosus originates on the tuberosity of the ischium (common tendon with the biceps femoris) and inserts on the upper medial condyle of the tibia. The semi- membranous also attaches to the tuberosity of the ischium bat the upper end and to the posterior medial condyle of the tibia at the lower. Because their tendons of insertion are in the medial (inner) side of the knee joint, they are known as the medial hamstrings.
Execution
You can do the standing leg curl most easily on an exercise machine. If no machine is available, you can use weight boots. The following description pertains to a standing leg-curl machine, but execution with the boot is basically the same.
Stand in front of the machine. Place the back of the lower leg to be exercised against the padded roller so that contact is on the Achilles tendon. Grasp the grips of the machine for balance.
Raise the heel until its above horizontal and allow the thigh to move forward slightly. Be sure you have firm contact with the roller. Slowly lower the leg back to the starting straight-leg position and repeat. Breathe in, and momentarily hold your breath as you raise the lower leg and exhale on the return. When you have done the desired number of repetitions, switch legs and repeat the process.
Joint Actions
The muscles involved in the standing leg curl perform knee-joint flexion. In this action, the back of the lower leg moves toward the posterior thigh, while the thigh moves forward slightly.
Sports Uses
For bodybuilders, leg curls are important to develop the middle posterior thigh, a key to the contour of that body part. Athletes in other sports require knee- joint flexion in running and kicking to bring the lower leg under the thigh as the leg comes forward in the main action phase before extension. Knee-joint flex-ion is also needed in back kicks in soccer and in different wrestling moves. Aerialists use this action whenever hanging from their knees on the trapeze.-Additional information from online sources.
The writer, Simon Gama is a fitness coach at Body Works Gym in Bulawayo.
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