Effect of an experimental fatigue protocol applied to the quadriceps femoris muscle of physically active persons

Abstract Aims: The purpose of this study was to test an experimental fatigue protocol for the knee joint extensor muscles performed on an isokinetic dynamometer. Method: SPIRIT recommendations were applied. Participants were 40 healthy, young men and women. Protocol: The pre-fatigue quadriceps femoris peak torque during concentric maximum voluntary contractions (MVC) at 60º/s was measured. During the first protocol part, the task was to do MVC at 60°/s until a sequence of five concentric MVC was below 40% of its initial value. For the second part, intermittent quadriceps femoris muscle and hamstrings maximum voluntary isometric contractions for 30 s (ratio 2/1 seconds). Thirty seconds after the isometric MVC (post-fatigue), they did three concentric MVC. Then, after 5 minutes of absolute rest, they did two concentric MVC. Men and women showed a lower peak torque due to this protocol (p < 0.001). Conclusion: This protocol was effective for fatigue men and women’s quadriceps femoris muscle.