Final answer:
The primary muscle being exhibited during a crunch is the rectus abdominis, which is responsible for flexing the spine.
Step-by-step explanation:
The primary muscle being exhibited during a crunch exercise is the rectus abdominis, commonly known as the abs. The rectus abdominis is responsible for flexing the spine, which is the main movement during a crunch. While other muscles such as the obliques and hip flexors also assist in the movement, the rectus abdominis is the prime mover in this action.
During a crunch, the rectus abdominis contracts and shortens, causing the shoulders to lift off the floor or mat. This muscle also works in tandem with the hip flexors to bring the torso closer to the hips. Additionally, the rectus abdominis plays a crucial role in maintaining good posture and stability in the core.
- Lie on your back with your knees bent and feet flat on the ground.
- Place your hands behind your head, keeping your elbows wide.
- Engage your core and lift your shoulders off the floor, focusing on using the abs to initiate the movement.
- Lower back down slowly and repeat for the desired number of repetitions
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