The Flywheel Leg-Curl Machine Offering Eccentric Overload for Hamstring Development

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 REVIEW: The Flywheel Leg-Curl Machine: Offering Eccentric Overload for Hamstring Development


Researchers took 20 male soccer players with previous training experience (half had flywheel experience and half did not) and reported kinetic, kinematic, and EMG data during two conditions of flywheel leg curls.  One condition used two flywheels to create a higher moment of inertia while the other condition only used one flywheel.  The protocol called for the use of the flywheel to create an eccentric overload by instructing participants to maximally accelerate the flywheel(s) through the entire concentric range of motion and then to decelerate the flywheel during only the second half of the eccentric contraction.  In this way, an eccentric overload was created in both conditions.

Key Results:

• Peak forces were higher in the two flywheels (greater inertial) condition

• Peak velocities were higher in the one flywheel (lesser inertial) condition

• Subjects familiar with the flywheel training did a better job of applying large eccentric forces later in the eccentric contraction.  This suggests that there may be some sort of learning period when teaching people to use a flywheel to create an eccentric overload.

• EMG activity of the hamstrings showed greater activity during flywheel exercise than in maximal voluntary isometric contractions.

• The biceps femoris showed a higher eccentric: concentric EMG rationthan did the semitendinosus, especially in the experienced flywheel users, suggesting that the biceps femoris may have a larger role than the semitendinosus during an eccentric contraction of the hamstring.

Review complete By JD Melhorn