Differences in the load-velocity relationship between untrained men and women during the back squat exercise

Objectives: The purposes of this investigation were: 1) to compare the load-velocity relationship estimated by the two-point method between untrained men and women during the parallel back squat exercise (BS) and 2) to compare the load-velocity profile found in our study with the load-velocity profiles reported in the scientific literature for trained individuals. Beyond, we aimed to compare the measured 1RM velocity with predicted 1RM velocity by the two-point method in the BS exercise in untrained individuals. Methods: Seventy-six untrained individuals (38 men (22.7 ± 4.4 years; 174.9 ± 6.8 cm; 76.1 ± 14.9 kg) and 38 women (24.7 ± 4.3 years; 159.1 ± 6.0 cm; 64.7 ± 13.3 kg) performed a one-repetition maximum test and a progressive two-load test with 20% 1RM and 70% 1RM to estimate their load-velocity relationships. Results: The main results revealed that 1) mean propulsive velocity and mean velocity attained at each relative load were different between men and women (p < 0.05). However, the measured 1RM velocity was not significantly different between them. Untrained men provided a steeper load-velocity relationship than women. We found that 2) untrained individuals of our study showed a different load-velocity profile than trained individuals from scientific literature studies. Furthermore, 3) the measured 1RM velocity was lower than the predicted 1RM velocity (p < 0.05). Conclusion: These results suggest that the load-velocity relationship is dependent on sex and training background, and the two-point method using 20% and 70% 1RM might not be reliable to estimate the load-velocity relationship in the BS exercise for untrained men and women.