Using Bar Velocity to Predict Maximum Dynamic Strength in the Half-Squat Exercise

Purpose: To determine whether athletes from different sport disciplines present similar mean propulsive velocity (MPV) in the half-squat (HS) during submaximal and maximal tests, enabling prediction of 1-repetition maximum (1-RM) from MPV at any given submaximal load. Methods: Sixty-four male athletes, comprising American football, rugby, and soccer players; sprinters and jumpers; and combat-sport strikers attended 2 testing sessions separated by 2-4 wk. On the first visit, a standardized 1-RM test was performed. On the second, athletes performed HSs on Smith-machine equipment, using relative percentages of 1-RM to determine the respective MPV of submaximal and maximal loads. Linear regression established the relationship between MPV and percentage of 1-RM. Results: A very strong linear relationship (R-2 approximate to .96) was observed between the MPV and the percentages of HS 1-RM, resulting in the following equation: % HS 1-RM = -105.05 x MPV + 131.75. The MPV at HS 1-RM was similar to 0.3 m/s. Conclusion: This equation can be used to predict HS 1-RM on a Smith machine with a high degree of accuracy.