(2) DOWNWARD PHASE DURATIONS IN ACCENTUATED ECCENTRIC LOADED BACK SQUATS IN RESISTANCE-TRAINED MEN

Abstract Details:

Purpose: The purpose of this study is to compare the downward duration of the back squat between
traditional back squats, maximal accentuated eccentric loaded back squats, and supramaximal accentuated
eccentric loaded back squats in resistance trained males.

Methods: 16 resistance-trained men (age =
24.7 ± 3.9 years, height = 176.9 ± 7.8 cm, body mass = 84.6 ± 12.7 kg, relative one repetition maximum
back squat [1RM BS] = 2.04 ± 0.28 kg/kg) participated in four testing sessions. The first session
consisted of a one 1RM BS testing and a familiarization with weight releasers that were used in later
sessions. The remaining three testing sessions were performed in a randomized order and required the
subjects to complete various squat conditions. During the traditional back squat condition, each subject
performed three BS repetitions with 50, 60, 70, and 80% of their 1RM BS. The second and third
conditions entailed performing three BS repetitions with 50, 60, 70, and 80% of their 1RM on the
concentric phase of the squat but performing the eccentric phase of the first repetition of each set with
either 100% (AEL100) or 110% of their 1RM (AEL110). Each BS set was performed on a force platform
where the raw force-time data were used to calculate the downward phase duration of the first repetition
of each set. The downward phase duration was determined as the combined duration of the unweighting
and braking phases of the BS. A three (condition) by four (load) repeated measures ANOVA test with
Bonferroni post hoc tests was used to compare the downward phase durations produced during the
different loading conditions. Hedge’s g effect sizes were also calculated to analyze the magnitudes of the
differences between the various conditions.

Results: There was significant main effect for condition (p
= 0.037) and load (p = 0.011) but not for the condition x load interaction effect (p = 0.065). The
downward phase duration data and post hoc analyses are displayed in Table 1. Trivial-moderate, small-
moderate, and trivial-small differences existed between loading conditions at 50, 60 and 70, and 80%
1RM, respectively.

Conclusions: The downward phase durations were similar between traditional
and AEL squatting conditions regardless of the added load in resistance-trained men. However, there was
a general trend indicating that heavier eccentric loads, such as those provided by AEL, may increase the
downward phase duration. PRACTICAL APPLICATIONS: Since downward phase durations may not
differ between traditional and AEL back squat conditions, strength and conditioning practitioners may
consider prescribing AEL using an individual’s natural movement tempo to provide the most effective
training stimulus. Future researchers may consider examining the downward phase duration differences
between stronger and weaker participants given the status of AEL as an advanced training strategy.

Acknowledgements: NONE