Muscles and joints act in a complex fashion in order to apply the forces required for every day movement and activity. In athletic endeavors, even greater forces are applied for rapid movement, pushing, pulling, twisting, throwing and many other applications of muscles, tendons and ligaments around joint movement.
Understanding the joints and how they are involved in weight training is important to understanding elements of good form in the gym and other applications of training the body for strength, muscle, and fitness.
There are approximately 206 primary bones in the human body, depending on extra bones and which minor bones get counted. The trunk, including skull, face, spine, sternum and ribs has 80 bones, and the extremities of the shoulder, hands, arms and feet have 126 bones. Here are the main joints of the body.
The Neck, Backbone and Vertebrae. form the spinal column. Each part of the spine and vertebrae has a distinct name. From the top: the cervical spine, the thoracic spine, and the lumbar spine. The backbone has a naturally curved shape called 'lordosis.' At the base of the spine is the sacrum, which connects with the pelvis, including the hips.
The Shoulder. The main bones of the shoulder are the scapula -- the large bones in the center of either side of the back better known as the shoulder blades; and the clavicle, which is the collar bone that runs across either shoulder. The shoulder joint is the most complex joint, being capable of rotation as well as flexion and extension. Injuries to the shoulder joint are common, even in non-active people.
The Pelvis and Hip. The pelvis includes the pelvic bone with the bony protuberances we generally call the hip bone (iliac crest). The sacrum at the bottom of the spine joins the pelvic bones on either side via the sacroiliac joints. These joints can be the source of poor back function and pain.
The Elbow. The elbow joint allows the arm to flex -- as in 'flex your biceps.' The humerus bone at the top of the arm joins with the radius and the ulna of the forearm at the elbow joint. Tennis elbow, in which a tendon becomes inflamed, is a common overuse injury.
The Wrist. The wrist is also susceptible to overuse injury. The bones of the forearm, the radius and ulna, join with a series of small bones, forming the wrist. These small bones are called the 'carpal bones.' An overuse injury called tenosynovitis is a common wrist injury, and this can occur in weight trainers who overtrain the wrist.
The Knee. Knee injuries are very common in athletes and recreational exercisers who compete in sports that require twisting and turning -- team sports like basketball, football and hockey. Knee reconstructions can require a person to be absent from their activity for up to a year. The knee joint has a complex arrangement of articulating bones, ligaments and cartilage. Comparatively, weight training does not elicit a high number of serious knee injuries.
The Ankle. Like the knee, the ankle joint is susceptible to twisting ligament sprains, sometimes involving broken bones such as the fibula. Also like the knee joint, twisting and turning activities at speed make the joint susceptible to injury.
Weight Training and Joint Protection
Compared to many other physical activities and sports, weight training is not especially hard on the joints of the body. The shoulder is probably the joint most injured, and this is likely to be a result of the complexity of the joint and the various loads and movement paths required in weight training for the upper body.
The golden rule for joint injury protection in weight training, or any activities for that matter, are:
- Practise good form.
- Start light and work up to heavier weights progressively.
- Know your limits and don't overload.
- Know your limits and don't overwork.
- Rest and recover from minor injuries.
- Seek medical diagnosis and assistance with chronic or serious acute injuries.