The number of fibers a fast twitch motor unit innervates is greater than that of a slow twitch, and the contractile mechanism of fast twitch muscle fiber is much larger. These factors combined mean a fast twitch fiber generates a force four times greater than a slow twitch fiber. Our strength and conditioning program improves functional strength and power with exercises and drills approximating these 3-dimensional skills. In strength and power training, only free weights allow movement in three dimensions simultaneously. This makes the transfer of strength and power easier to merge with the development of sport skills.
Machines limit the development of sport skills.
For example, when you use free weights, the muscles regulate and coordinate the movement pattern of the resistance, while machines use lever arms, guide rods, and pulleys to dictate the path of the movement. An additional benefit from using free weights is their ability to help prevent major joint injuries. For example, squatting using free weights requires the back and abdominal muscles to stabilize the torso isometrically. This allows the legs and hips to work with the back and abdominals as a unit to perform the lift. Whereas the adjustable seat back on the hip sled or leg press substitutes as the back and abdominal stabilizers restricting movement and isolating muscle contractions to the hips and legs.