Flywheel resistance training calls for greater eccentric muscle activation than weight training

Abstract

Changes in muscle activation and performance were studied in healthy men in response to 5 weeks of resistance training with or without "eccentric overload". Subjects, assigned to either weight stack (grp WS; n = 8) or iso-inertial "eccentric overload" flywheel (grp FW; n = 9) knee extensor resistance training, completed 12 sessions of four sets of seven concentric-eccentric actions. Pre- and post-measurements comprised maximal voluntary contraction (MVC), rate of force development (RFD) and training mode-specific force. Root mean square electromyographic (EMG(RMS)) activity of mm. vastus lateralis and medialis was assessed during MVC and used to normalize EMG(RMS) for training mode-specific concentric (EMG(CON)) and eccentric (EMG(ECC)) actions at 90°, 120° and 150° knee joint angles. Grp FW showed greater (p < 0.05) overall normalized angle-specific EMG(ECC) of vastii muscles compared with grp WS. Grp FW showed near maximal normalized EMG(CON) both pre- and post-training. EMG(CON) for Grp WS was near maximal only post-training. While RFD was unchanged following training (p > 0.05), MVC and training-specific strength increased (p < 0.05) in both groups. We believe the higher EMG(ECC) activity noted with FW exercise compared to standard weight lifting could be attributed to its unique iso-inertial loading features. Hence, the resulting greater mechanical stress may explain the robust muscle hypertrophy reported earlier in response to flywheel resistance training.

Effects of a 10-Week In-Season Eccentric-Overload Training Program on Muscle-Injury Prevention and Performance in Junior Elite Soccer Players

“…By controlling the execution technique (ie, delaying the braking action in the eccentric phase), these devices enable achievement of a given degree of eccentric overload. 10,16,21,25 In the leg-curl exercise, participants performed a bilateral knee flexion in a prone position (Figure 2) by accelerating and decelerating the flywheel through a concentric, and subsequently eccentric, action of the hamstrings muscle group. Participants were encouraged to apply the maximum effort from the knee-extension position (0°) to a 130° to 140° flexion and then asked to resist the movement during the eccentric phase when the 90° position was reached.…”

“…[11][12][13] Traditionally, strengthening programs are based on resistance exercises where the stimulus is provided by gravitational loads.methods is limited to concentric actions, with lower activation in the eccentric phase. 15,16 Therefore, preventive strength-training strategies might also include exercises where muscles are activated during the eccentric phase for an adequate muscle response. 10 It seems that eccentric strengthening exercises for the quadriceps and hamstrings reduce the thigh muscle strain-injury rate in soccer.…”

“…eccentric and concentric knee-flexor strength and in maximal sprinting speed. In this regard, it has been reported that NHE and flywheel exercises can produce greater eccentric overload 10,14 and greater muscle activation (measured by electromyography [EMG]) 16 than traditional exercises. However, despite the difficulty in matching the intensities between the NHE and the YoYo leg-curl exercise, it seems that the YoYo leg curl provides a much higher eccentric overload than the NHE.…”

Acute neuromuscular response during eccentric overload protocol by using a mechanical device to increase the load

“…The flywheel consists of a spinning flywheel that allows the ECC action to be performed under higher loads then the CON action. Nevertheless, the flywheel system is limited because the load during the ECC action is not constant throughout the range of motion 17 . A group of researchers developed a machine that allows ECC overload throughout the contraction without assistance 14 ; however, it was limited to a few muscle groups.…”

Eccentric Overload Training and Injury Prevention during Running

“…Different exercises produce an eccentric overload, like plyometric, drop jumps or downhill running, but isoinertial devices avoid joint impacts and maybe that is why they are widely used in the last years to increase the eccentric phase [10] having an important work also during the concentric. Tissue adaptations caused by eccentric overload training are apparent, but the increased load of the eccentric training can increase pain and muscle damage markers in subjects under training [11], increasing resting metabolic rate during 72 h [12], so we must take these in account when scheduling training loads.…”