Ability of closed and open kinetic chain tests of muscular strength to assess functional performance.

The purpose of this study was to investigate the ability of closed and open kinetic chain tests of muscular strength to assess functional performance. Sixteen healthy male subjects, with a mean (+/-SD) age, body mass and height of 27+/-5 years, 78+/-9 kg and 183+/-9 cm, respectively, volunteered to participate in the study. In the closed kinetic chain test (involving muscles working across multiple joints), the subjects performed a 3 repetition maximum (3 RM) barbell squat. The open kinetic chain test (involving muscles working across a single joint) consisted of a concentric isokinetic knee extension at an angular velocity of 60 degrees/s, and was performed using a Kinetic Communicator II dynamometer. The test of functional performance (vertical jump) was performed with the subject standing erect, quickly performing a countermovement jump for maximal height. Moderately strong significant (P<0.05) correlations between the test of functional performance and the closed and open kinetic chain tests of muscular strength were noted, r=0.51 and r=0.57, respectively. It is suggested that the effect of training or rehabilitation interventions should not be based exclusively on tests of muscular strength. Rather, various forms of dynamometry including functional performance tests could be recommended.