OBJECTIVE: We tested peak torques of knee extensors and knee flexors using an isokinetic dynamometer (Cybex model 770) in middle-aged and aged populations, and calculated functional hamstring: quadriceps ratios (H/Q ratios) and conventional hamstring: quadriceps ratios. We present the normative data of these parameters in decade age groups for both sexes. METHOD: Using an isokinetic dynamometer we determined the peak torques of knee extensors and knee flexors at angular velocities of 30, 60 and 180 degrees/sec in normal people (120 males, 154 females in the age range 31 to 70 years) and using these peak torque values to calculate functional H/Q ratios and conventional H/Q ratios. RESULTS: Normative data were presented. As age increased, the magnitudes of the peak torques of most knee flexors and knee extensors decreased, but conventional and functional H/Q ratios were not found to be significantly correlated with age in either sex. CONCLUSION: Normative data by decade age in both sexes were obtained. It is hoped that this data will be beneficial for the testing of knee joint function.