Question

A soccer player performing a penalty kick will hyperextend their hips while eccentrically activating their quads, before quickly activating their quads in a concentric manner. What is the term for this technique and what is the point of doing it?

Answer 1

The technique is called concentric-eccentric muscle action, and it is used to generate maximum force and power in a soccer kick.

Step-by-step explanation:

The technique described in the question is called the concentric-eccentric muscle action.

During a penalty kick in soccer, the player hyperextends their hips while lengthening their quadriceps muscles (eccentric activation), and then quickly contracts their quadriceps muscles to kick the ball (concentric activation).

The point of using this technique is to generate maximum force and power in the kick.

The eccentric activation of the quadriceps muscles allows the muscles to store and absorb energy, which is then released during the concentric contraction to produce a powerful and fast kick.

Answer 2

The technique describing the hyperextension of hips followed by activation of quads in both eccentric and concentric manners is known as the stretch-shortening cycle, used to generate more force. For the angular acceleration given, the force exerted by the muscle on the soccer player's leg can be calculated using torque and moment of inertia, resulting in approximately 1184.21 N.

Step-by-step explanation:

The technique of a soccer player first hyperextending their hips and eccentrically activating their quads, before performing the action of kicking by concentrically activating their quads, is known as stretch-shortening cycle (SSC). The SSC takes advantage of the elastic properties of the muscles and connective tissues, allowing the player to generate greater force during the concentric manner of the movement. This phenomenon underpins many explosive movements in sports where rapid and powerful muscular contractions are required.

Calculating the force exerted by the muscle during a kicking motion involves physics. If a soccer player produces an angular acceleration of 30.00 rad/s² and the lower leg has a moment of inertia of 0.750 kg·m² with a lever arm of 1.90 cm or 0.019 m, we use the formula τ = I·α, where τ is torque, I is moment of inertia, and α is angular acceleration. To find the force F, we rearrange the relationship τ = F·r, getting F = τ/r.

Therefore, the force exerted by the muscle is F = (I·α)/r, which is (0.750 kg·m² · 30.00 rad/s²)/0.019 m, resulting in a force of approximately 1184.21 N.