Relationship between closed-linear-kinetic- and open-kinetic-chain isokinetic strength and lower extremity functional performance

Context. lsokinetic strength and functional performance are used to assess recovery after rehabilitation. It is not known whether low-speed closed-lin ear-kinetic isokinetic muscle strength correlates with functional performan ce. Objective: To investigate the relationship between linear closed (CKC) and open (OKC) concentric isokinetic strength of the dominant lower-limb extens ors and functional performance. Design: Correlational analysis. Setting. University laboratory. Participants: Thirty uninjured men and women (age = 20.9 +/- 2.4 years). Main Outcome Measures: Peak CKC and OKC isokinetic strength and best score from a shuttle run for time, single-leg vertical jump, and single-leg hop f or distance. Results. Neither lower-limb CKC nor OKC isokinetic strength measured at low speeds correlated highly with performance on the functional tasks of jumpi ng, hopping, and speed/agility. Conclusions: Although the basis of both closed and open isokinetic strength must be appreciated, they should not be the only determinants of functiona l performance.