There are lots of muscles in the body, and they work together to perform various movements for activities of daily living. On a deeper level, muscles can be broken down into both superficial muscles and deep muscles. In "Hole's Essentials of Human Anatomy and Physiology," authors Butler and Lewis explain that superficial muscles are more surface-based and can be easily seen when performing most major movements of the body.
Pectorails Major and Trapezius
The pectoralis major and trapezius are two of the larger superficial muscles groups in the human body. These two muscles groups are responsible for two separate movements. The pectoralis major is responsible for protracting and externally rotating the scapula. The pectoralis major is strengthened during an exercise such as pushups. The trapezius is primarily responsible for retracting and elevating the scapula. The trapezius is strengthened during exercises such as shoulder shrugs and seated rows.
Latissimus Dorsi
The latissimus dorsi is a very powerful muscle group that runs from the ribs to the sacrum. This muscle is responsible for adduction and extension of the shoulder and depression as well as downward rotation of the scapula. The latissimus dorsi is strengthened during an exercise called the lat pulldowns.
Biceps Brachii and Triceps Brachii
The biceps brachii and triceps brachii are located directly opposite of each other. Both muscles also perform the opposite movements. The biceps brachii performs flexion at the elbow and is strengthened with an exercise such as biceps curls. The triceps brachii performs extension at the elbow and is strengthened by doing triceps extension resistance exercises.
Quadriceps and Hamstrings
The quadriceps muscle group and the hamstrings muscle group are also located directly opposite of each other. The quadriceps muscle group is composed of four muscles that primarily perform extension at the knee. The quadriceps muscle group can be strengthened with an exercise like leg extensions. The hamstrings muscle group is composed of three muscles that primarily perform flexion at the knee. The hamstrings can be strengthened by doing hamstring curls against resistance.
Deltoids
The deltoids muscle group is one of the smaller superficial muscle groups in the body. The deltoids muscle group is responsible for flexion and upward rotation at the shoulder. The deltoids can be strengthened by doing a variety of exercises against resistance such as shoulder press, lateral raises and front raises.
Abdominals
The abdominal muscle sheath is one of the most noticeable muscles in the body. The abdominals are responsible for flexion at the lumbar portion of the spine. The abdominal muscles can be strengthened by adding external resistance-based exercises.
References
- "Hole's Essentials of Human Anatomy and Physiology." J. Butler and R. Lewis. 2006.
