TORQUE-JOINT ANGLE RELATIONSHIP FOR VASTUS LATERALIS MUSCLE

Abstract

The aim of this work was to study a single muscle torque contribution during a knsee extension in different knee angles. Six subjects performed three tasks: maximum voluntary knee extension (MVC), supramaximal twitch of relaxed quadriceps femoris muscle, and contraction of relaxed vastus lateralis muscle, activated with a train of submaximal electrical impulses.~A ll contractions were performed at angles of 450, 600, 750, and 900 at the knee joint and in a supine position (hips extended). In both tasks with the electrical stimulation (ES) the same stimulation parameters were used in all angles. Results showed that relative torques (100% at 450) for MVC and the twitch were merely the same, exhibited a maximum (143.6% and 153.1%, respectively) at 750 and fell to 133.3% and 137.4% at 900. Vastus lateralis muscle attain its maximum (1 16.8%) at 600 and fell continuously to its minimum of 602 % at 900. It is possible to see that a single head of the quadriceps muscle behaves in a much different way as the whole quadriceps muscle. Establishing a torque joint angle relationship for single muscles or muscle groups may be interesting for muscles' dynamics modelling, used in a professional work.