Explain the class of lever system in use when the athlete moves from standing onto her toes. Explain why this gives the athlete mechanical advantage.
The class of lever system in use when the athlete moves from standing onto her toes is a third-class lever system. In this type of lever system, the fulcrum is located at one end of the lever, the resistance is located at the other end of the lever, and the effort is located in between the fulcrum and the resistance.
When the athlete moves from standing onto her toes, the effort is provided by the muscle contraction in the calf muscle, which is located between the ball of the foot (which acts as the fulcrum) and the weight of the body (which acts as the resistance). The mechanical advantage of this lever system is that the effort required to lift the body onto the toes is less than the weight of the body itself because of the distance between the ball of the foot and the ankle joint. This means that the athlete can generate more force with less effort, making it easier for her to move onto her toes.
When the athlete moves from standing onto her toes, it involves the use of a third-class lever system. In a third-class lever system, the effort force is applied between the fulcrum and the resistance force.
In this scenario, the fulcrum is located at the balls of the feet, where the toes bend. The effort force is applied by the muscles in the calf, specifically the gastrocnemius and soleus muscles. The resistance force is the body weight of the athlete, acting on the lever through the ankles.
This lever system provides the athlete with a mechanical advantage. Mechanical advantage refers to the amplification of force achieved by using a lever system. In a third-class lever system, the mechanical advantage is less than 1, which means the effort force needs to be greater than the resistance force.
In the case of the athlete moving from standing onto her toes, the mechanical advantage arises from the position and action of the muscles involved. By contracting the calf muscles, the athlete can generate a force greater than her body weight. This force is transmitted to the ball of the foot, creating a rotational movement around the ankle joint and enabling the athlete to rise onto her toes.
Although the mechanical advantage may be relatively small in a third-class lever system, it allows the athlete to generate more force than if she were relying purely on her body weight. This can be particularly advantageous for activities such as jumping, running, and various athletic movements that require explosive force production.