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In most strength training programs, weight lifting tempo is expressed as eccentric-to-isometric-to-concentric, which means that a 3:1:1 tempo = 3 sec. eccentric : 1 sec. isometric : 1 sec. concentric. While TUT in the eccentric phase provides a strong stimulus for muscle growth, the overall goal of the training program, the amount of intensity used and the client’s experience dictate the tempo of an exercise.

SOURCE: 

https://www.acefitness.org/resources/pros/expert-articles/4931/weight-lifting-tempo-amp-sets-how-to-select-the-right-sets-for-your-clients/#:~:text=In%20most%20strength%20training%20programs,concentric.