Which is the strongest muscle in the human body when measured by force relative to its own size?
- The biceps brachii, in the upper arm
- The gluteus maximus, in the hip
- The masseter, in the jaw
- The quadriceps femoris, in the thigh
Why C? And why not the others?
Correct answer: C. The masseter, in the jaw
The masseter is the strongest muscle in the body for its size, because its job of clamping the jaws shut works through an unusually short, mechanically efficient lever arm, letting a comparatively small muscle generate an enormous bite force per gram of tissue. The option naming the body's largest muscle by sheer mass, the muscle of the hip, is a natural trap, since being biggest and being strongest-for-its-size are different measurements entirely. The muscle group that powers standing, walking, and jumping in the thigh moves the largest overall loads in absolute terms, but relative to its bulk it is far less efficient than the jaw muscle. The muscle famous for flexing the elbow is comparatively small and weak, prized for visibility rather than force.
Source: Guinness World Records: Strongest muscle; Encyclopaedia Britannica: What is the strongest muscle in the human body based on its size?