(09) BRAKING FORCE-TIME CHARACTERISTICS BETWEEN TRADITIONAL SQUATS AND FLYWHEEL INERTIA SQUATS AT DIFFERENT LOADS

Purpose: The purpose of this study was to examine the differences in braking force-time characteristics between traditional back squats and flywheel inertia squats performed using a spectrum of loads.

Methods: 17 resistance-trained subjects took part in this research study including 9 men (age=24.7±4.0 years, hheight=171.7±5.8 cm, body mass=77.9±11.2 kg, relative one repetition maximum [1RM] back squat=2.01±0.26 kg/kg) and 8 women (age=23.0±2.1 years, hheight=167.6±8.6 cm, body mass=71.5±7.7 kg, relative 1RM back squat=1.43±0.25 kg/kg). Each subject participated in three total sessions over the course of one week. During the first testing session, each subject completed a 1RM back squat and were familiarized with flywheel inertia squats. During the subsequent two testing sessions, the subjects performed three repetitions each of the free weight back squat exercise with 40, 50, 60, 70, and 80% of their 1RM back squat or flywheel squats using inertial loads of 0.010, 0.025, 0.050, 0.075 and 0.100 kgm². The traditional and flywheel squat session order was randomized. All squat repetitions were performed on dual force plates sampling at 1000 Hz. Raw force-time data were collected and exported for analysis within a customized spreadsheet. Braking mean force, duration, and impulse were compared using a series of 2 (condition) x 5 (load) repeated measures ANOVA. In addition, Hedge’s g effect sizes were calculated between conditions to examine the magnitude of the differences at each load.

Results: The descriptive data for each load and mode are displayed in Table 1. There was a significant interaction between mode x load for eccentric mean force (p< 0.001), and duration (p=0.008) but not for braking impulse (p=0.513). In addition, there was a significant load main effect for braking impulse (p< 0.001) but not for mode (p=0.140). Large-very large effects favoured traditional squats for braking mean force (g =1.66-2.70). The differences in braking duration between conditions were small-moderate (g=0.25-1.00). Finally, the effect sizes between conditions for eccentric impulse were trivial-moderate (g=0.12-0.76).

Conclusions: Significantly greater braking mean forces were produced during traditional squats compared to flywheel squats. In contrast, braking durations were significantly greater during flywheel squats compared to traditional. There were no significant differences between squat conditions for braking impulse; however, moderate effect sizes favouring the traditional condition were present at the lightest loads. PRACTICAL APPLICATIONS: The desired training adaptation may influence the decision to use one training mode over another. Traditional squats may be more beneficial for braking rapid force production as greater force may be produced over shorter durations. However, flywheel training may provide a novel braking stimulus to individuals who almost exclusively use traditional exercises within their training programs.  

 

Acknowledgements: none