Final answer:
Nick should focus on core training to alleviate the pressure on his back, knees, and shoulders.
Core exercises strengthen the muscles in the abdomen, lower back, and hips, providing stability and support to the spine.
Therefore, the correct answer is: option c) core.
Step-by-step explanation:
Any exercise that involves the use of your stomach muscles and back muscles in a coordinated way counts as a core exercise.
In this case, if Nick's back, knees, and shoulders often feel sore and tired, he should focus on core training. Core exercises help to strengthen the muscles in the abdomen, lower back, and hips, which can provide stability and support to the spine and reduce stress on other body parts.
Examples of core exercises include planks, Russian twists, and bird dogs. By strengthening his core, Nick can alleviate some of the pressure on his back, knees, and shoulders.
In addition to core exercises, Nick can also benefit from aerobic exercise, such as swimming or cycling, to improve cardiovascular fitness and promote overall strength and endurance.