Physiological Quadriceps Lag

Aim

To evaluate whether quadriceps lag exists in normal healthy individuals.

Objective

1. To analyze if quadriceps lag exists in healthy adults

2. To analyze if this quadriceps lag increases with a sustained contraction of 5 seconds

3. To analyze the difference in quadriceps lag between males and females.

Design

Repeated measures desig.n

Method

A study of active and passive limit of knee extension was carried out on 48 healthy adults.With the subject seated for the passive test the examiner lifted the heel until the relaxed knee sagged into full extension under its own weight. The active test component comprised maximum active extension held for atleast 5 seconds.Videotaped reference markers on the lateral aspect of the limb were computer analyzed to derive the active and passive knee extension.

Result

The active limit of knee extension was less than the passive limit by an average 5.04 degrees at the instant of maximum knee extension and by 6.34 degrees and 7.22 degrees at 3 and 5 seconds respectively. At 0 and 5 seconds 45.7% and 72.9% of the subjects manifested a quadriceps lag of atleast 5 degrees. There is also no significant difference, in the quadriceps lag manifested in males and females.