How Are Mechanical, Physiological, and Perceptual Variables Affected by the Rest Interval Between Sets During a Flywheel Resistance Session?

Rafael Sabido,Julio Tous-Fajardo,Laia Capdepon,Jose Luis Hernández-Davó

doi:10.3389/fphys.2020.00663

Abstract

The use of flywheel devices has increased in popularity during the last few years. Flywheel training is an attractive alternative to traditional resistance exercise because it allows for the loading stimulus to be manipulated. Some of the benefits associated with flywheel training include increases in muscle hypertrophy, muscular strength and reductions in injury risk. Nevertheless, there is a lack of research about how basic training variables [i.e., rest intervals (RI) between sets], or variables associated with manipulation of the loading stimulus (i.e., different inertial loads), influence the acute responses during a flywheel session. Thus, the aim of this study was to assess the influence of three different RI between sets (1, 2, or 3 min), during a flywheel squat session with two different inertial loads: light (0.025 kg⋅m2) and high (0.075 kg⋅m2). Twenty-three participants performed six exercise sessions (two inertial loads × three RI) consisting of four sets of 11 repetitions. Concentric and eccentric power, lactate concentration ([La]) and ratings of perceived exertion (RPE) were measured during the exercise session, and delayed onset muscular soreness (DOMS) were recorded 24 h post-exercise. Both concentric (9.1 and 22.1% at light and high load respectively; p = 0.022 and 0.005) and eccentric peak power (17.5% at high load; p = 0.02) decreased across sets when the 1 min RI was used. Concentric peak power was decreased (11.1%, p = 0.041) from the 2 min RI only with the high inertial load. RPE was higher during the 1 min compared with the 3 min RI protocol when using the high inertial load (p = 0.028). [La] was higher when using the 2 min RI compared with the 3 min RI at light load (p = 0.03). In conclusion, during flywheel training sessions, a short RI (1 min) was insufficient to maintain power output across all four sets and was linked to greater perceptual variables. A 2 min RI allowed for power to be maintained, but only when training with light inertial loads. Based on these results, coaches should consider prescribing 3 min RI’s when performing flywheel squat exercises regardless the inertial load. In contrast, when using 2 min RI’s the inertial load should be light.

Highlights

Strength training is considered crucial for the progressive adaptation in muscular strength and performance (American College of Sports Medicine [ACSM], 2009)
Concentric (PPconc), eccentric (PPecc) peak power, and eccentric to concentric power ratio (Ecc/Conc Ratio) across each set, ratings of perceived exertion (RPE) and lactate concentration [La−] after the session, and muscular soreness (DOMS) at 24 h for the three different rest interval durations are presented in Table 1 for the light load and in Table 2 for the high load
The main finding was that the 1 min rest intervals (RI) protocol entailed significant concentric and eccentric power output decrements, as well as increases in RPE compared with the 3 min RI protocol at high load

Summary

Introduction

Strength training is considered crucial for the progressive adaptation in muscular strength and performance (American College of Sports Medicine [ACSM], 2009). When training for power adaptations, some authors have recommended long RIs between sets (>3 min) (Abdessemed et al, 1999; Pincivero and Campy, 2004), based on the fact that power output is dependent on the phosphagen energy system. Hydrogen ions might accumulate, resulting in a decrease in intramuscular pH This effect might negatively influence muscular performance by reducing force and/or power production (Pincivero and Campy, 2004; de Salles et al, 2009). The detrimental effects in acute neuromuscular and hormonal responses resulting from RI’s that are too short may impact chronic adaptations, including strength gains, hypertrophic effects, and sensitivity of the muscles receptors to circulating hormones (Kraemer and Ratamess, 2005; de Salles et al, 2009)

Objectives

Methods

Results

Discussion

Conclusion