Repetitive Strain Injury (RSI) is an injury to muscles, joints or nerves that may be caused by repetitive tasks, forceful exertions, vibrations, pressing against hard surfaces, and sustained or awkward positions. Bass guitar players do just about all of that! Therefore they are vulnerable to RSI. We repeatedly fret and pluck our strings for hours, sometimes forcefully, we press a forearm against the body of our instrument, keep our wrists in awkward angles, support diving necks and bend over to watch our fretting hand. We drag around heavy equipment, have quite a few beers and return home from gigs in the dead of night. We suffer from stage or recording fright and conflicts with band mates or sound guys. All of these factors,are known to contribute to RSI.
Always keep in mind that correct technique will not prevent RSI; it will only help to prevent it. Even professional players with flawless technique may be struck by RSI, specificly when they have to keep on working through periods of physical or mental health problems or stressful and fatigueing projects.
To prevent RSI, respect the limits of your physical possibilities. Take good care of both body and mind. Have regular breaks. Relax. Joints are best kept in a more or less neutral position. Muscles should not be contracting constantly.The next pages will help you to monitor your technique and to adopt a way of playing allowing you to stay away from extremes.
Much more rare is focal_dystonia. It causes undesirable contraction in a muscle group and is mostly due to overtraining. Especially music students and professional players run the risk of getting it. It may cause the fingers to bend in or stretch, keeping them locked in that position.
Unlike RSI, focal dystonia is a purely neurological condition. It is irreversable.
As RSI can partly be prevented by applying correct technique and moderation, focal dystonia can only be prevented by moderation. Some famous musicians with awesome technique have unfortunately been affected by it.