Reference values for concentric knee isokinetic strength and power in nonathletic men and women from 20 to 80 years old

Abstract

Study design: A prospective, controlled, randomized study.

Objective: To establish reference values for prediction of concentric isokinetic knee strength and power in a sample of nonathletic men and women.

Background: Adequate interpretation of knee isokinetic strength and power relies on a representative frame of reference. However, none of the most widely cited prediction studies used a randomly selected sample of nonathletic subjects, therefore limiting the clinical application of these studies.

Methods and measures: We evaluated the concentric right and left knee extensor and flexor peak torque, total work, set total work, average power, and torque acceleration energy (Cybex 6000 System) in 96 healthy subjects (45 men and 51 women, aged 20 to 80), randomly selected from more than 8000 individuals.

Results: By stepwise regression analysis, we found that gender, age, weight, height, and regular physical activity explained up to 84% of the variability of the dependent variables: a set of linear prediction equations for strength (at 60 degrees/s) and power (at 300 degrees/s) is provided.

Conclusions: Results from this study might provide a clinically useful frame of reference for interpretation of concentric isokinetic knee strength and power in nonathletic men and women.