What does Newton's First Law state in relation to biomechanics?

Newton's First Law of Motion, also known as the Law of Inertia, asserts that an object at rest will remain at rest and an object in motion will continue in motion at a constant velocity unless acted upon by a net external force. This principle is foundational in biomechanics, as it explains how and why objects (including human bodies) behave in the way they do under different conditions of motion or rest.

In the context of biomechanics, this law helps to illustrate the resistance of bodies to changes in their state of motion. For instance, when a person is standing still, they will not start moving unless a force (like a push) is applied to them. Similarly, a moving person will continue to run at the same speed and in the same direction until forces (such as friction or muscular force) act to change that motion. Understanding this concept is critical in activities like sports, rehabilitation, or even everyday movement, where external forces can significantly influence performance and safety.

The other options raise relevant concepts in mechanics, but they pertain to different laws or principles. For instance, the idea that a body will change shape relates to material properties and stresses rather than motion. The notion of force applied being equal to mass times acceleration describes Newton's Second Law,