Effects of Flywheel Training on Strength-Related Variables: a Meta-analysis

Abstract

Background: Strength and power development are abilities important for athletic performance in many sports. Generally, resistance training based on gravity is used to improve these qualities. Flywheel training instead utilizes kinetic energy transferred to a flywheel. This allows for eccentric overload and variable resistance throughout the movement. The aim of this review was to identify the effects of flywheel training on multiple strength-related variables affecting athletic performance. The meta-analysis investigates the effects on (1) muscle growth (cross-sectional area (CSA) and volume/mass), (2) maximum dynamic strength, (3) development of power, (4) development of horizontal movement, and (5) development of vertical movement.

Methods: The meta-analysis includes 20 experimental studies that met the inclusion criteria. The quality of included studies was ranked according to the PEDro scale. Possible bias was identified in Funnel plot analyses. To enable the compilation of all results analyses, the random effect model was carried out using the software Review Manager Version 5.3 and presented with Forest plots.

Results: Flywheel training for a period of 4-24 weeks shows statistically significant increases in all strength aspects. Effect sizes were for hypertrophy, CSA 0.59; volume/mass 0.59; maximum strength 1.33; power 1.19; horizontal 1.01 and vertical movement 0.85. The evidence is particularly strong for beneficial effects from flywheel training in the development of maximal strength and power in trained younger individuals, and utilization of this training modality in shorter more intensive blocks.

Conclusions: Flywheel training is an effective method for improving several aspects of strength and power with importance for sports performance.

Keywords: Horizontal movement; Maximum strength; Muscle hypertrophy; Power; Vertical movement.

Fig. 1

A typical flywheel machine. Pictured is YoYo™ Ultimate Squat (model #215) with Hooper’s Box. Courtesy by nHANCE™ driven by YoYo™ Technology—Copyright© 2018. All rights reserved

Fig. 2

Flow chart of study selection for inclusion in the meta-analysis. n number of studies, CSA cross-sectional area

Fig. 3

The equation used for the calculation of pooled standard deviations. SD standard deviation, n number of study participants

Fig. 4

Forest plot showing effect size comparing pre and post-test muscle cross-sectional area during a period of 5 to 8 weeks of flywheel training [15, 36, 42, 43, 47]. [+] indicates positive effect of flywheel training. SD standard deviation, Std standardized, IV inverse variance, CI confidence interval

Fig. 5

Forest plot showing effect size comparing pre and post-test muscle volume/mass during a period of 5 to 8 weeks of flywheel training [, , , , , , –43, 45]. [+] indicates positive effect of flywheel training. SD standard deviation, Std standardized, IV inverse variance, CI confidence interval

Fig. 6

Forest plot showing effect size comparing pre and post-test maximal strength during a period of 4 to 10 weeks of flywheel training [, , , , , , , , –44, 47, 48]. [+] indicates positive effect of flywheel training. SD standard deviation, Std standardized, IV inverse variance, CI confidence interval

Fig. 7

Forest plot showing effect size comparing pre and post-test power during a period of 4 to 24 weeks of flywheel training [, , , , , , –46, 48]. [+] indicates positive effect of flywheel training. SD standard deviation, Std standardized, IV inverse variance, CI confidence interval

Fig. 8

Forest plot showing effect size comparing pre and post-test horizontal displacement during a period of 6 to 10 weeks of flywheel training [29, 40, 44, 45, 48]. [−] indicates positive effect of flywheel training, i.e. decreased times. SD standard deviation, Std standardized, IV inverse variance, CI confidence interval

Fig. 9

Forest plot showing effect size comparing pre and post-test vertical displacement during a period of 5 to 24 weeks of flywheel training [27, 29, 34, 37, 44, 45, 48]. [+] indicates positive effect of flywheel training. SD standard deviation, Std standardized, IV inverse variance, CI confidence interval