A subject with elbows held at 90 degrees of flexion is handed a 150 lb (68.1kg) barbell. Even though he exerts maximal tension, the barbell causes the joint angle to increase to 170 degrees. Which one of the following describes the muscle action during the extension?

Question

A subject with elbows held at 90 degrees of flexion is handed a 150 lb (68.1kg) barbell.  Even though he exerts maximal tension, the barbell causes the joint angle to increase to 170 degrees.  Which one of the following describes the muscle action during the extension?

Quizplus · Accepted Answer

If the joint angle increased during the muscle action, it means that the muscle was lengthening while generating tension, which characterizes an eccentric contraction. Additionally, since the weight was constant throughout the movement, it was an isotonic contraction. Therefore, the best choice is B) Isotonic eccentric.

A Subject with Elbows Held at 90 Degrees of Flexion