Key Takeaway
Eccentric-overload flywheel training produces significant improvements in both skeletal muscle structure (hypertrophy, fascicle length) and function (strength, power) compared to conventional resistance training.
Summary
This systematic review and meta-analysis by Maroto-Izquierdo et al. (2018) examined the structural and functional adaptations of skeletal muscle following eccentric-overload flywheel resistance training. The review included studies comparing flywheel training to traditional resistance exercise or control conditions, and assessed outcomes including muscle cross-sectional area, fascicle length, maximal voluntary contraction, and power output. The pooled results showed that flywheel training produced significantly greater gains in muscle hypertrophy and fascicle length — structural changes that reflect both increased contractile protein content and serial sarcomere addition. On the functional side, flywheel-trained groups demonstrated superior improvements in strength and power. The authors attributed these enhanced adaptations to the unique eccentric overload provided by the flywheel mechanism, which imposes higher forces during the lengthening phase than the trainee can generate concentrically. This systematic evidence supports flywheel training as a method that goes beyond matching conventional training, offering distinct structural remodeling advantages relevant to both athletic performance and injury prevention.