The most common cause of a sprained wrist is the impact an individual's hand makes with the ground when breaking a fall. People instinctively thrust out their hands when tripping and falling, often making the wrist the first body part to absorb shock. When the wrist makes impact with the ground or other object, the ligaments can become stretched and even torn. Sprains occur when ligaments sustain such damage. Any activity that increases the risk of falling increases the risk of a sprained wrist. Most sports fall under this category as well as other athletic activities, such as running.
Accidents or collisions while playing sports are the most common cause of a sprained wrist. Athletic activities, such as soccer, football, tennis and skateboarding, greatly increase one's chance of falling, and therefore the chance of sustaining a wrist injury. When the wrist impacts with the ground, it's usually in such a way that the bottom of the palm hits first. This causes the hand to bend backward, which causes the ligaments in the wrist to stretch. As a result, the ligaments may be stretched to the point of minor damage, causing a Grade I sprain, or to the point of tearing, causing a Grade II or III sprain.
There are also plenty of non-sport related incidents in which people are more likely to fall and suffer a sprained wrist. For example, people often sprain their wrists from slipping and falling in icy weather. Tripping and falling down stairs is another common cause.
There can also be situations in which hitting the ground is not the cause of a sprained wrist. For example, a skier with poles might have fallen and sprained his or her wrist, but the sprain didn't come from impact with the ground. Instead, it came from the skier's hand becoming tangled up in the pole straps, causing the wrist to bend too far in the wrong direction. Likewise, if an individual incorrectly lifts a heavy object, the weight can cause the wrist to bend too far or incorrectly, resulting in a sprain.
When engaging in athletic activities, there are ways to protect against the possibility of a sprained wrist. In skateboarding and inline skating, for example, it's all but guaranteed that one's wrists will absorb falls on a regular basis. For that reason, participants in those activities often wear wrist guards for protection. Wrist guards are affordable accessories that strap on to the wrist and feature a hard, plastic barrier that provides separation between the wrist and the ground in the event of a fall.