A patient with a lower-extremity muscle strain and quadriceps strength of grade 3 is prescribed strengthening in a seated position. Which contraction would permit the greatest amount of weight to be used?

• A. Concentric contraction with a cuff weight on the ankle
• B. Eccentric contraction with a cuff weight on the ankle
• C. Isometric contraction with a cuff weight on the ankle
• D. There would be no difference in the maximum amount of weight the patient could utilize

Answer: (B)

A key idea here is that muscles can generate more force during eccentric (lengthening) contractions than during concentric (shortening) contractions. In a seated knee exercise with an ankle cuff, using the eccentric phase means the quadriceps lengthens while controlling the external load, so the muscle can handle a heavier weight than it could if it were trying to lift the weight concentrically. This higher force capacity during lengthening occurs because of how muscle fibers produce force while lengthening and the contribution of passive elastic elements. Since the patient is working against gravity but with a strengthening focus, eccentric loading lets you use a larger resistance while maintaining control, which is why it permits the greatest amount of weight.