Intra- and Inter-Day Reliability of Inertial Loads with Cluster Sets When Performed during a Quarter Squat on a Flywheel Device

Abstract

The aims of this study were to (i) estimate the intra- and inter-day reliability of mean concentric (CON) and eccentric (ECC) power at different inertial loads during a flywheel quarter-squat using a cluster set approach and (ii) to determine the acute effect of internal and external attentional focus on mean power when performing the flywheel quarter squat. Twelve collegiate field sport male athletes (age 22.4 ± 3.2 years, weight 81.4 ± 10.3 kg, height 1.81 ± 0.06 m) attended four cluster set testing sessions separated by 7 days. Sessions consisted of 4 sets of 15 repetitions using 4 inertial loads (0.025, 0.050, 0.075, and 0.100 kg·m2). A cluster block consisted of 5 repetitions, including “momentum repetitions” (4 × 5 + 5 + 5). Mean power (MP), CON power, ECC power, and ECC overload were recorded for both internal and external attentional focus groups. The external instructional group attained familiarization after two flywheel sessions (ES = 0.03–0.15) with little volatility between performance measures (CV% = 3.39–9.22). The internal instructional group showed large differences in MP output from session 2 to session 3 for all loads (ES = 0.59–1.25). In conclusion, the flywheel cluster set approach is a reliable training modality for maintaining MP output during all repetitions.

Test-Retest and Inter-Rater Reliability of a Rotary Axis Encoder-Flywheel System for the Assessment of Hip Rotation Exercises

“…The encoder-flywheel system has shown adequate validity when compared to IDs [16,17]. Nevertheless, the reliability of these devices has only contrasted for functional movements like squats or quarter squats [7,10,18,19]. The reliability of physical performance tests depends not only on the joint and the executed movement, but also on the measurement protocol, including the assessment position and the fixation system, like with IDs [4].…”

Flywheel Romanian Deadlift: Intra- and Inter-Day Kinetic and Kinematic Reliability of Four Inertial Loads Using Cluster Sets

“…A familiarization period, initial momentum repetitions, and adequate progressions are required for stability and optimal FIT performance [ 5 , 8 ]. To date, two studies have examined the familiarization period during a quarter-squat exercise and the stability of performance measures with both CON and ECC power output (mean and peak), showing good-to-excellent levels of reliability when using the exercise [ 7 , 9 ]. During one of these studies, attentional focus was examined as a mode to enhance the skill acquisition process and decrease the required number of sessions to reach familiarization [ 9 ].…”

“…To date, two studies have examined the familiarization period during a quarter-squat exercise and the stability of performance measures with both CON and ECC power output (mean and peak), showing good-to-excellent levels of reliability when using the exercise [ 7 , 9 ]. During one of these studies, attentional focus was examined as a mode to enhance the skill acquisition process and decrease the required number of sessions to reach familiarization [ 9 ]. The findings suggested the superiority of external instructional instructions during this process.…”

“…A recent study reported the effects of a FIT cluster set (CS) training approach utilizing intra-set rest periods during the familiarization process to reinforce technical form instructions and prevent fatigue accumulation during the familiarization process [ 9 ]. The study established excellent reliability in the CS approach, independent of inertial load.…”

“…To the best of our knowledge, only one previous study has investigated a familiarization phase using a flywheel CS training approach [ 9 ]. Thus, the primary aim of this study was to investigate the intra- and inter-day reliability of flywheel cluster set training in concentric power (CON), eccentric power (ECC), and ECC overload during the RDL.…”