Final answer:
To maintain a healthy back, the abdominal muscles and core muscles should be strengthened, including the external obliques, internal obliques, transversus abdominis, and rectus abdominis.
Step-by-step explanation:
To maintain a healthy back, it is essential to strengthen the muscles of the abdominal wall and the deep core muscles. These muscle groups include the external obliques, internal obliques, transversus abdominis, and rectus abdominis. Strengthening these areas helps in extending, flexing, and stabilizing different parts of the body's trunk, contributing to better posture and reducing the risk of back problems.
The muscles that must be specifically targeted to ensure a healthy back are the abdominal muscles, rather than the quadriceps, biceps, or deltoids. While other muscles, like the gluteal muscles which are responsible for extension of the hip joint, also play a role in overall posture and stability, the primary focus should be the abdominal region when considering back health.