(59) SEX DIFFERENCES IN THE FORCE-VELOCITY CURVE AND 1RM PREDICTION DURING BACK SQUAT

Purpose: To assess differences in the force-velocity curve between males and females during the back squat exercise. Further, examine differences in the prediction of 1-repetition maximum (1RM) from submaximal repetition velocity.

Methods: 11 recreationally trained, college-aged participants (Male: 6, Female: 5) were recruited for this study. Participants completed anthropometric, body composition, and back squat 1RM testing on day 1. On day 2 participants performed a submaximal squat protocol consisting of 5 repetitions at 30, 40, 50, 60, and 70%, and 3 repetitions at 80 and 90% of their 1RM in a randomized order. During 1RM and submaximal testing, average linear velocity was measured with a linear position transducer (Tendo Sports Machines, Slovak Republic) and knee average angular velocity was measured with accelerometer affixed to the mid-thigh (OUTPUT sports, Ireland). Furthermore, rating of perceived exertion was reported after each set of submaximal exercise. 1RM was estimated by determining the individual load-velocity relationship then determining the load at the measured 1RM velocity. Differences in 1RM linear and angular was assessed via independent samples t-test. Differences in linear and angular velocity during the submaximal protocol was assessed via mixed factorial ANOVA. Cohen’s d was calculated for each gender comparison.

Results: Men (1.93±0.18 kg/kg body mass) had a significantly higher relative 1RM (p=0.017, d=1.666) than women (1.48±0.37 kg/kg body mass). Also, men (34.11±4.14 deg/s) had slower angular velocity (p=0.006) at 1RM than women (44.50±5.41 deg/s), but there was no significant difference in linear velocity (p=0.240) at 1RM between men (0.26±0.09 m/s) and women (0.32±0.07 m/s). During the submaximal protocol, there was a significant load×gender interaction for linear velocity (p< 0.001), but no interaction effect for angular velocity (p=0.081). Post hoc tests revealed that men had a significantly faster linear velocity at 30% (p=0.005, d=1.84), 40% (p=0.006, d =1.77), and 50% (p=0.042, d=1.13). In terms of predicted 1RM from linear velocity, men had a significant difference (p=0.046, d=0.95) between actual 1RM (176.91±30.98 kg) and 1RM predicted from linear velocity (187.26±28.95kg), while women presented a trend for a difference (p=0.075, d=1.07) between actual 1RM (97.52±30.94 kg) and predicted 1RM from linear velocity (113.70±37.01 kg). In terms of predicted 1RM from angular velocity, neither men (p=0.976, d=0.01) or women (p=0.171, d=0.75) presented a significant difference between actual and predicted 1RM.

Conclusions: In the current study, men had a higher relative 1RM than women, which may have resulted in a slower angular velocity; however, had no effect on linear velocity. Furthermore, men produced faster linear velocity than women at sets of 30%, 40%, and 50% 1RM, while there was no difference in angular velocity during submaximal loads. The predicted 1RM from angular velocity was not significantly different from the actual 1RM in men or women, while predicted 1RM from linear velocity was different from actual 1RM for men and trended different for women. Practical Applications: The apparent gender differences in linear velocity during submaximal exercises are important to consider when using velocity-based training, particularly at lower loads. Measuring angular velocity may be a more accurate way to predict 1RM and may not be as affected by gender during submaximal sets of back squat.

Acknowledgements: None