Muscle performance is commonly assessed on the field by various test procedure based on jump(s) or sprint(s). This chapter presents a review of the classical jump and sprint test, their methodology, their utility and their limitations. Less functional than these tests reproducing a sport movement are the tests and training methods based on isolated muscle contraction. These contractions can be isometric, eccentric, concentric, isokinetic or free. Training adaptations are dependent of contraction velocity or articulation angle. Training adaptations as well as fatigue effects are dependent of both peripheral (e.g., muscle) and central (e.g., neural drive) modifications. Lastly, the reproducibility of some standard test is presented.