The effect of a needle biopsy of the vastus lateralis on isokinetic muscular performance.

OBJECTIVE

To determine the acute effects of a needle muscle biopsy of the vastus lateralis on knee extension and flexion strength and endurance.

DESIGN

Pretest-posttest design. Testing order of right or left leg was randomly determined.

SETTING

Research Laboratory, University of Alberta, Edmonton Alberta, Canada.

PARTICIPANTS

The subjects were 8 female and 11 male volunteers who were recreationally active. The mean age, height, and weight were 23 +/- 5 years, 174.6 +/- 9.2 cm, and 73.5 +/- 7.3 kg, respectively.

INTERVENTION

Isokinetic testing for knee extension and flexion was performed on both legs before and after a biopsy of the right vastus lateralis muscle.

MAIN OUTCOME MEASURES

Knee extension and flexion peak torque measured at an angular velocity of 1.05 rad.s-1. Mean torque during 25 consecutive maximal contractions at 3.14 rad.s-1 for knee extension and flexion exercise.

RESULTS

There was a significant decrease in right knee extension peak torque after the biopsy of the vastus lateralis muscle. No other differences were noted.

CONCLUSIONS

These findings demonstrated an acute inhibition of knee extension peak torque but not endurance because of a muscle biopsy of the involved musculature.