Microdosing of Flywheel Training: Effects of Low Versus High Training Frequency on Muscle Mass, Strength, and Power.

Microdosing flywheel resistance training—five short daily sessions per week—improved muscle thickness, fascicle length, and fascicle angle in the thigh muscles of active individuals, while once-weekly training with the same total volume did not. Both regimens similarly increased leg strength and jump performance. However, the microdosing group reported much lower perceived exertion and muscle soreness throughout the six-week program. The findings suggest that spreading resistance training into small daily doses can enhance muscle architecture and reduce fatigue, offering a practical alternative for athletes with congested schedules or people in rehabilitation.

Study at a glance

Abstract

This study compared the effects of low-frequency flywheel resistance training (FRT, 1 session/week) and microdosing FRT (5 sessions/week) on muscle architecture, strength, and vertical jump performance in active individuals. Thirty participants were randomized into a microdosing group (MDG, n = 15) or a control group (CG, n = 15). Both groups completed equalized weekly training volumes (30 sets over 6 wk) using a flywheel leg press. The MDG performed one set daily, whereas the CG performed 5 sets once weekly. Vastus lateralis and rectus femoris muscle thickness, vastus lateralis fascicle length and angle, maximal voluntary isometric contraction in the half-squat exercise, countermovement and drop jump performance, rating of perceived exertion, and delayed-onset muscle soreness were assessed preintervention and postintervention. MDG showed significant (P < .001) increases in muscle thickness (vastus lateralis: 9.8%, 0.21 cm, effect size [ES] = 0.41; and rectus femoris: 7.9%, 0.18 cm, ES = 0.34), fascicle length (11.8%, 0.96 cm, ES = 0.81), and fascicle angle (14.2%, 2.29°, ES = 1.16), drop jump RSI (24.4%, ES = 0.97), and drop jump take-off velocity (5.7%, ES = 0.27) while CG showed no significant changes. Both groups showed improved maximal voluntary isometric contraction (MDG: 27.4%, ES = 0.72; CG: 18.6%; ES = 0.48), countermovement height (MDG, 7.7%, ES = 0.34; CG: 5.9%, ES = 0.17), and countermovement mRSI (MDG, 32.1%, ES = 0.98; CG: 34.0%, ES = 0.60) with no intergroup differences. However, MDG reported significantly (P < .001) lower rating of perceived exertion and delayed-onset muscle soreness scores throughout the intervention. FRT microdosing improved muscle architecture, while strength and power gains were similar to low-frequency FRT. Importantly, microdosing reduced fatigue and soreness, offering a practical alternative during competitive congested schedules or in rehabilitation settings.