(9) FORCE AND VELOCITY SET TO SET ANALYSIS OF ACCENTUATED ECCENTRIC LOADED SQUATS IN RESISTANCE-TRAINED WOMEN

Abstract Details: FORCE AND VELOCITY SET TO SET ANALYSIS OF ACCENTUATED ECCENTRIC LOADED SQUATS IN RESISTANCE-TRAINED WOMEN
L.K. Marshall1,2, B.A. Campbell2,3, C.J. Cantwell2, Z.S. Schroeder2,4, J.B. Chard2, A.E. Sundh2, C.B. Taber5, and T.J Suchomel2
1University of Wisconsin-Platteville, Platteville, WI, 2Carroll University, Waukesha, WI, 3University of Wisconsin-Whitewater, Whitewater, WI, 4Morningside University, Sioux City, IA, 5Sacred Heart University, Fairfield, CT

Purpose: The purpose of this study was to examine the effect of multiple sets of accentuated eccentric loading (AEL) on force-time and velocity characteristics in the back squat (BS) in resistance-trained women.

Methods: 13 resistance-trained women (age: 23.7 ± 2.7 years, body mass: 70.5 ± 8.7 kg, height: 166.4 ± 6.8 cm, one repetition maximum (1RM) back squat: 103.9 ± 11.5 kg, relative 1RM back squat: 1.5 ± 0.2 kg/kg) with previous BS experience participated in two testing sessions. During the first testing session, the subjects completed BS 1RM testing and were familiarized with using weight releasers. In the second testing session, subjects performed three sets of three repetitions of the BS using weight releasers on the first repetition of each set to allow for change in loading from the eccentric phase prior to initiation of concentric phase. During this session, participants performed the AEL BS with an eccentric load of 100% 1RM BS and concentric load of 80% 1RM BS. Each BS repetition was performed on a force plate and a linear position transducer device was used to identify barbell position. The force-time data from the force plate was used to calculate propulsive net mean force (PMF), duration (PDur), and net impulse (PImp) using forward dynamics while the displacement-time data from the linear position transducer was used to calculate mean (MBV) and peak barbell velocity (PBV) during each repetition. The average performance across each repetition was used for statistical analysis. A series of one-way repeated measures ANOVA were used to examine the potential differences in propulsive force-time and barbell velocity characteristics across the sets performed. Hedge’s g effect sizes were also calculated to determine the magnitude of the differences between sets.

Results: The force-time and barbell velocity characteristics produced during each set are displayed in Table 1. There were no significant differences across sets for PMF (p = 0.420), PDur (p = 0.088), PImp (p = 0.605), MBV (p = 0.149), or PBV (p = 0.962). In addition, only trivial to small differences existed across all sets for every variable.

Conclusions: There were no significant differences observed between sets for all variables, indicating that propulsive force-time and barbell velocity characteristics were maintained. PRACTICAL APPLICATIONS: The current results suggest that resistance-trained women can maintain force and velocity metrics across multiple sets of AEL BS using a heavy loading combination of 100% and 80% 1RM during the eccentric and concentric phases, respectively. Although this loading combination may be implemented as an effective strength stimulus for resistance-trained women, further research is needed to determine if a heavier or lighter load combination may provide superior results.

Acknowledgements: None