Final answer:
An isometric contraction occurs as the muscle produces tension without changing the angle of a skeletal joint. Isometric exercises are those where muscle contraction occurs without changing the length of a muscle or the angle of a joint.
Step-by-step explanation:
An isometric contraction occurs as the muscle produces tension without changing the angle of a skeletal joint. Isometric contractions involve sarcomere shortening and increasing muscle tension, but do not move a load, as the force produced cannot overcome the resistance provided by the load. For example, if one attempts to lift a hand weight that is too heavy, there will be sarcomere activation and shortening to a point, and ever-increasing muscle tension, but no change in the angle of the elbow joint. In everyday living, isometric contractions are active in maintaining posture and maintaining bone and joint stability.
Isometric exercises are those where muscle contraction occurs without changing the length of a muscle or the angle of a joint. In other words, the muscle is contracting, but there is no visible movement at the joint. Examples of isometric exercises include plank, wall sit, and static squats.