Basketball is a game of profound athletic contrasts. There are graceful, even elegant, movements that appear to defy gravity, that occur in a larger context of physical contact between large, powerful athletes. Impact will often occur between players with little warning and at full speed, with the athletes' bodies contorted in different angles at the point of impact. The nature of these athletic movements creates a wide variety of forces upon the basketball player's body, which in turn creates an equally broad range of potential athletic injuries. Injuries in basketball will arise both as a specific incident of trauma, as well as an overuse condition resulting over time.
As basketball demands quick and explosive movements to be made by players both running and jumping, the most common injury sustained is to the ankle. Ankle sprains occur with some frequency, either as a result of the player landing in a position where the foot is not stable, causing the ankle to roll outward on impact, or where the player lands upon another player's foot, which also creates an uneven surface and causes the foot and the ankle to roll outward. It is a rare competitive basketball player who has not sustained a number of at least minor ankle sprains in their career. Many players, especially at the upper echelons of competition, wear an ankle support or brace as a preventative measure; alternatively, one or both ankles will be taped to provide additional support to the ankle.
Player size is also a factor in the severity of an ankle sprain. In the National Basketball Association (NBA), the average player is 6 ft 8 in (2.03 m) tall, weighing approximately 225 lb (102 kg); in the elite European leagues, average player sizes are only somewhat smaller. The greater size of these athletes, coupled with their general ability to leap higher than the average person, will magnify the forces applied to the ankle.
A less common, and potentially devastating, ankle injury is an Achilles tendon rupture. This injury often occurs in circumstances in which the player is making an explosive movement, usually leaping for a rebound or to challenge an opponent's shot. An Achilles injury of this severity will require surgery and significant rehabilitation, with the risk that unless careful rehabilitative attention is paid to the calf muscles and supporting structure, the athlete will lose a degree of flexibility and corresponding leaping ability in future.
Knee injuries are also a common feature of basketball. Knee sprains commonly occur when a player twists the knee, resulting in a tiny rupture of one of the three knee ligaments; the sprain typically does not immobilize the athlete, but will require rest, ice, and compression, and often a protective padding or a brace over the joint on the athlete'return to practice or games. A more serious twisting of the knee joint may often occur when the player is planting or pivoting a foot to change direction, and the knee is then unexpectedly struck from the opposite direction. This force may result in a torn cartilage (meniscus). Once a feared injury that necessitated extensive surgery and rehabilitation, this damage is now commonly resolved through much quicker arthroscopic surgery processes.
"Jumper's knee" is a common overuse-related injury to the patella tendon, the fibrous linkage running beneath the knee cap to the tibia (shin bone). Excessive jumping, sometimes in conjunction with a poorly aligned knee cap, will cause the tendon fibers to become irritated and inflamed, which causes the jumping motion to be painful. This condition is best treated with rest and ice. The player should also examine the shoes used for excessive wear or other evidence of improper cushioning on landing, factors which may contribute to the misalignment of the leg during jumping.
The most serious and potentially limiting knee injury sustained in basketball is the tear of the anterior cruciate ligament (ACL). The ACL connects the tibia to the femur (thigh bone), and is the ligament in the knee responsible for ensuring the stability of the center of the joint. A blow to the side of the knee or a sudden, non-contact change of direction by an athlete can cause this injury. An ACL tear, which may be accompanied by tears to the adjacent medial collateral ligament (MCL), will prevent an athlete from meaningful running or jumping. The repair of this injury requires surgery, and the rehabilitative process can extend from 9 to 12 months.
It is to be noted that female basketball players (and female athletes generally) are at a significantly greater risk of sustaining an ACL tear. This heightened risk is due to the different construction of the female body in contrast to that of males: the ratio of the hip width to femur length in a female (known as the "Q" line) tends to be greater than that in a male. The Q line illustrates that a female's ACL will be subjected to greater pressure on impact or from explosive movement than the male's ACL.
Both the knees and the quadriceps (thigh) muscles located above the knees commonly sustain injury through contact with an opponent's knee in competition. Such injuries are generally contusions (bruises). A blow from the knee of an opponent to a large muscle structure such as the quadriceps can be both painful and debilitating.
The nature of basketball creates a number of potential circumstances for hand, wrist, and finger injuries. These injuries occur primarily from the player's hand making contact with the ball at an angle where the joint in question is not in a position to absorb the shock, or where the player falls awkwardly on the fingers or wrist. The degree of force sustained will determine whether the joint is sprained, a common event for a basketball player, which is readily resolved by taping the joint or joints in question, or is fractured.
Unlike movements such as a golf swing, passing a football, or throwing a baseball, the most fundamental action in basketball, the act of shooting, is not itself an activity that is likely to lead to a repetitive strain-type injury.