Which type of contraction occurs during a plank position?

Which type of contraction occurs during a plank position?

• A. Isotonic concentric
• B. Isometric
• C. Isotonic eccentric
• D. Plyometric

Answer: (B)

Isometric contraction occurs when muscle tension increases to hold a position without changing the muscle length. In a plank, you brace your core and keep your body straight against gravity, with no joint movement. The muscles stay activated to stabilize the spine and hips, but they don’t shorten or lengthen noticeably, which is the hallmark of an isometric hold. By comparison, isotonic contractions involve movement: concentric shortens the muscle as it produces force to lift or bring parts of the body closer, and eccentric lengthens the muscle while it controls lowering or lengthening a limb. Plyometric actions involve rapid, explosive movements that use quick stretch-shortening cycles. The static nature of a plank makes isometric contraction the correct description.

Isometric contraction occurs when muscle tension increases to hold a position without changing the muscle length. In a plank, you brace your core and keep your body straight against gravity, with no joint movement. The muscles stay activated to stabilize the spine and hips, but they don’t shorten or lengthen noticeably, which is the hallmark of an isometric hold.

By comparison, isotonic contractions involve movement: concentric shortens the muscle as it produces force to lift or bring parts of the body closer, and eccentric lengthens the muscle while it controls lowering or lengthening a limb. Plyometric actions involve rapid, explosive movements that use quick stretch-shortening cycles. The static nature of a plank makes isometric contraction the correct description.