Final answer:
Resistance in exercise should be positioned in the plane of motion of the body part being worked. For exercises on an inclined plane, gravitational force splits into perpendicular and parallel components, with resistance often opposing the parallel component. Proper alignment of resistance helps in matching the anatomical movement for effective training.
Step-by-step explanation:
In the context of exercises and biomechanics, the resistance should be placed in the plane of motion that corresponds to the movements of the body part being exercised. When an object, such as a limb during exercise, is on an inclined plane, it experiences different forces acting upon it. The force of gravity can be resolved into two components: a force perpendicular to the plane (w₁) and a force parallel to the plane (w⫭). The perpendicular force is typically balanced by the normal force (N), while the parallel force influences the motion down the incline and is opposed by friction (f).
For effective exercise, resistance is commonly applied in a direction that opposes the intended muscle action. For example, during a weightlifting squat, resistance (weight) is aligned with the gravitational pull (vertically), because the primary motion of the squat is the vertical rise against gravity. However, when using resistance machines or equipment that allows resistance to be applied from different angles (such as cables or bands), it's important to align the resistance to match the anatomical plane of motion of the specific exercise for optimal training effects.