Skip to main content
2023 NSCA National Conference Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.
Back

Speed/Power Development

(10) ACCENTUATED ECCENTRIC LOADED BACK SQUATS: RELATIONSHIPS BETWEEN RELATIVE STRENGTH AND BRAKING IMPULSE CHARACTERISTICS

Saturday, July 15, 2023
10:45 AM – 11:00 AM East Coast USA Time
Location: Milano I-II
Abstract Details:

Purpose: To examine the relationships between relative strength and braking impulse characteristics during accentuated eccentric loaded back squats (AEL BS).

Methods: 14 resistance-trained men (age = 24.8 ± 3.9 years, height = 177.9 ± 8.4 cm, body mass = 86.3 ± 13.1 kg) with previous BS experience participated in two separate testing sessions. The subjects completed one repetition maximum (1RM) BS testing and were familiarized with using weight releasers during the first testing session. Relative BS strength was calculated as the ratio between the 1RM of each subject and their body mass. During the following testing session, the subjects performed sets of three repetitions of AEL BS with the eccentric phase of the first repetition being loaded with 110% of the subject’s 1RM and the concentric phase being performed with either 50, 60, 70, or 80% 1RM. Using this loading method, 60, 50, 40, or 30% of the total load was added using weight releasers. The BS were performed on a force platform and the force-time data were used to calculate the net braking phase impulse of each repetition. In addition, a linear position transducer was attached to the barbell to help identify the end of the braking phase. The start of the braking phase was identified as the point where force exceeded the system mass (subject + concentric load). The end of the braking phase was identified as the point where peak force occurred prior to the propulsion phase and was confirmed using the displacement-time data from the linear position transducer. The braking impulse of each repetition was calculated as the product of the braking mean force and duration and the average performance across repetitions was used for correlational analysis. Pearson correlation coefficients (r) and coefficients of determination (R2) were used to examine the relationships between relative BS strength and the braking impulse characteristics during each AEL BS set.

Results: The relative BS strength and braking impulse descriptive statistics and relationships are displayed in Table 1. Statistically significant relationships existed between relative BS strength and the braking impulse produced during each of the AEL BS sets. 62.4, 58.5, 62.7, and 68.4% of the braking impulse variance was explained by relative BS strength when the concentric phase was performed with 50, 60, 70, and 80% 1RM, respectively.

Conclusions: Very large relationships existed between relative BS strength and the braking impulse characteristics produced during AEL BS sets. PRACTICAL APPLICATIONS: AEL BS may provide a unique braking stimulus compared to traditional BS due to the ability to use supramaximal loads during the eccentric phase. However, the current results suggest that the braking stimulus may be directly impacted by an individual’s relative BS strength. AEL may be considered an advanced training strategy for resistance-trained men; however, further research with different populations is needed to support these findings.

Acknowledgements: None