Swimming is usually considered a risk free sport, but there are some potential injuries to keep in mind.
Repetitive overhead arm action can create tremendous stress to the shoulder. Poor technique, excessive workload, or the use of swim paddles and pull buoys can cause different syndromes including rotator cuff tendonitis, biceps tendonitis, and subacromial tendonitis:
To avoid shoulder injuries :
During freestyle, keep the head in line with the spine and the eyes looking straight down at the bottom of the pool. Avoid looking too far forward or lifting the head forward to breathe. During backstroke, swim distance must be increased gradually so that the anterior neck muscles have time to adapt.
Low Back Pain
Strong core muscles are essential, mainly abdominal muscles, which helps to sustain the body in a neutral degree of flexion/extension. Low back injuries are caused by excessive repetitive arching when performing free style, breaststroke or butterfly. Perform a gradual warm up and vary your strokes at the first sign of discomfort.
Being proactive can avoid unwanted cramps, by warming up before rigorous parts of your swimming and by staying consistently hydrated. Some cramps can go away while swimming, but it is recommended to leave the pool to stretch. Cramps often occur in muscles that cross two joints, the calf muscle for example. Poor conditioning, muscle fatigue and dehydration can lead to cramps.