Relationship between Absolute and Relative Strength with Velocity Decline during the Back Squat
Average concentric velocity (ACV) can be used to objectively measure fatigue and intensity during resistance training and to assist in attempt selection during one-repetition maximum (1RM) testing. However, ACV may be different across individuals at similar intensities of 1RM, making it difficult for investigators to make objective load increases during 1RM testing. Further, it is unknown how strength levels are related to velocity at particular percentages of 1RM. Purpose: Therefore, the purpose of this study was to examine the relationship between absolute and relative strength in the back squat with ACV at various percentages of 1RM. Methods: Twenty-five college-aged, resistance trained men (Age: 23 ± 3 years, Body Mass: 87.70 ± 16.11 kg) performed a 1RM back squat followed by 2 single repetition sets at 30, 40, 50, 60, 70, 80, and 90% of the established 1RM. Three to 5 minutes of rest were administered between each single repetition set and the best velocity of the 2 sets at each intensity was used for analysis. ACV was calculated on each set using the Open Barbell System Version 2 (Seattle, WA, USA) linear position transducer. Wilks coefficient, a valid measure of relative strength, was also calculated from the 1RM squat. The difference between ACV at 90% of 1RM and ACV at 30% of 1RM was calculated and used as ACV decline. Pearson's product moment correlations were used to assess relationships between absolute and relative strength and ACV decline. Results: Mean squat 1RM was 167.0 ± 42.5, mean Wilks Coefficient was 109.75 ± 21.55 and mean ACV decline from 30 to 90%1RM was 0.65 ± 0.11m·s−1. There was a significant moderate correlation between 1RM and ACV decline from 30 to 90% 1RM (r = 0.48, p = 0.01). Additionally, there was a significant moderate correlation between relative back squat strength and ACV decline from 30 to 90% 1RM (r = 0.56, p= < 0.01). Conclusions: Our findings suggest that lifters with greater absolute and relative strength will experience a larger decrease in ACV between 30 and 90% of their 1RM. These findings may be due to stronger lifters possessing greater neuromuscular efficiency, resulting in a slower ACV at high percentages of 1RM; thus, displaying greater velocity decline from low to high intensities. Practical Applications: Therefore, if utilizing velocity based training at high intensities a stronger lifter might be prescribed a slower ACV than a weaker lifter.
Las Vegas, NV
Varieur, R.; Haischer, M. H.; Cooke, D. M.; Carzoli, J. P.; Helms, E. R.; Byrnes, R. K.; Johnson, T.; Davis, E. P.; Bazyler, Caleb D.; Zoeller, R. F.; Whitehurst, M.; and Zourdos, M. C.. 2017. Relationship between Absolute and Relative Strength with Velocity Decline during the Back Squat. NSCA National Meeting, Las Vegas, NV. https://journals.lww.com/nsca-jscr/Fulltext/2017/12001/Abstracts.3.aspx