Musicians are very prone to injury. Due to the nature of practicing an instrument, executing precise movements for extended periods of time and over the course of many days (often every day), many musicians find themselves suffering from injury at some point in their career. The motion is usually concentrated in the hands, arms and sometimes feet, most instruments demand a particular posture in order to play and are really full-body activities. There is little wonder that there are anatomy books specifically targeted to musicians and physiotherapists who specialize in treating them.

Even if you have never experienced an injury playing an instrument don't make the mistake of assuming you are immune. Certain injuries may take time to surface, such as tendinitis, at which point you may be locked in to bad habits that are difficult to reverse. You should be observing all the following practices in order to minimize the likelihood of injury:

Always warm up and cool down
You wouldn't run the 100m dash without getting your muscles warmed up ahead of time, so don't play your instrument with a doing the same. It's very easy to think that this is something you can skip, but the risk of tearing, pulling, straining something is not worth it. You may accumulate micro-tears which you won't notice at the time, but that will eventually form scar tissue. A combination of stretching and simple exercises is ideal.

Observe proper posture
Whether you are seated or standing make sure you position yourself and your instrument properly. There should be a minimal amount of tension required to achieve this. Consider your entire body, for you may be positioning something oddly or tense somewhere you didn't even realize. Proper posture will make it much easier to play your instrument.

Know your instrument
With the size, shape, and weight of your instrument determines how you will hold it and execute movements with it. Some instruments, such as guitars, come in many varieties and it is possible to look for one which has dimensions that suit you. Whether or not this is the case, there are ways to minimize the amount of strain you put on your body. This may be a particular strap, chair, strain gauge, mallet size etc.

Observe your playing technique
Everybody's technique will be slightly different based on their unique body proportions. However, it is good to educate yourself about the fundamentals of good techniques on your instrument. Your movements should use the minimum amount of exertion necessary. One thing you will never see is a world-class musician who looks as if playing their instrument is a great physical burden.

Listen to your body
Taking breaks will benefit both your mind and body. It will also give you an opportunity to assess how you feel. It is less likely you will realize something is wrong when you are intently focused on practicing. If you are fatigued or aching stop. There'll be plenty of other days for you to practice. If you want to stay involved, listen to some music or practice mentally.

Playing an instrument involves the whole body. Exercising regularly will help you prevent fatigue and strain while you play. It also helps improve focus and alertness.

Consult a specialist
If you think you may have injured yourself don't hesitate to seek a professional opinion. Most overuse injuries are easily treated if caught early, but it becomes progressively more difficult the longer you wait.