Overuse Injuries

The term overuse injuries is descriptive and makes sense to the layperson which is why I've used it in the title. Medically it is an overused one however. Overuse injuries are a specific subset of what are now called Cumulative Trauma Disorders (CTD's), repeated low grade damage to muscle and connective tissue that never gets a chance to heal due to the constant use. Overuse injuries are characterised by repetitive movements where other CTD's are caused by both dynamic and static loading.

The likelihood of injury is greater when the forces involved increase and when the limbs are positioned in other than a neutral position. Biomechanical analysis then of the repetitive movements is vital in the long term resolution of these injuries.

Biomechanical loading is the result of forces produced both externally and internally through the contraction of muscle tissue, and are borne by collagenous connective tissue. They can occur at muscles, ligaments, tendons and bones, structures which all have strong connective tissue components. CTD's that affect the bone, such as shin splints, are uncommon in musicians while most soft tissue injuries tend to show damage to tendon, muscle and ligaments. Nerve tissue is also affected by CTD's.

Tendinopathies

Tendinopathy is the general term used to describe tendon injuries such as tendonitis, tendinosus and tenosynovitis. The muscle tendon is a strong fibrous tissue rich in collagen that conects the rest of the muscle usually to bone but sometimes to other tendons. These injuries used to be thought of as inflammatory conditions, similar to acute strains, but recent research, while not yet finding a solid alternative theory, has well and truly discounted this idea.

It is widely accepted however that problems with the collagen matrix in the connective tissue are related to tendinopathies. Some researches have proposed that it involves series of microscopic tears while others have added that the friction created by the debris from these disruptions causes further damage to the local tissue. The immediate results of cortisone injections with these injuries points to some indication of the collagen matrix and refutes the old infammation theories. It should be added that repeated cortisone injections can make tendons brittle and are ill-advised.

Tenosynovitis is a specific conditions affecting the synovium, a slippery connective tissue coating that helps to lubricate tendons in compact areas such as the wrist and hand.

Muscle injuries

Myofascial trigger points develop over time in hypertonic muscle tissue. The muscle develops localised areas of knotting that are hard, tender and sometimes cause pain elsewhere in the body. They tend to appear in well defined areas and refer pain to equally well defined regions. A common one in musicians is in the upper trapezius just below the ears on top of the shoulder.

Ischaemia is a state in which blood, and therefore oxygen, supply is reduced. It can be caused by damage to or inclusion (blockage) of blood vessels or in areas such as the supraspinatus tendon in the shoulder that are poorly vasculated. Ischaemic muscles tend to be painful when they contract. The pain is thought to be due to an increased build up of metabolites and/or the compression of pain receptors around dry, tight muscle fibres. Proponents of the trigger point theory suggest that long term ischaemia will lead to the development of trigger points. This idea is consistent with what I and most myofascial therapists see in clinic.

Muscle strain occurs when muscle fibres are torn, either in an acute unjury or over time. Muscle tears in CTD's are smaller, usually microscopic but still result in weakness, pain and and can lead to more serious problems such as those just described. Muscle strain due to postural loading is very common amongst musicians and guitarists are not immune to it. The many and varied postural approaches we tend to take, usually ruled by habit more than technique, tend to significantly exacerbate the problem.

Cramp is caused by contraction of shortened muscle and best relieved by stretching. It is exacerbated when muscles are fatigued and inflexible, dehydration and heat are also factors. Cramping in the left hand and forearm is common when we conitnue to play after the arm becomes fatigued. There are mountains of information in the program that deals with the causes of fatigue, inflexibilty and what to do about them.

Apart from these purely medical definitions the main problem is a general lack of conditioning brought on by the 21st century lifestyle. Our bodies have evolved to be hunters and gatherers, we're supposed to run for days, throw spears and wrestle tigers and most of us don't. We develop areas of weakness, tightness, some muscles are too short and others are too long and then we sit down for four hours hunched around a guitar, a bit silly really.

Ligament injuries

Most ligament injuries are relatively rare in musicians and tend to accompany tendon injuries, in which the treatment principles are the same: rest, reconditioning and rehabilitation of the offending activity.

Nerve injuries

Nerve injuries are not much fun, they tend to develop over time as with long term muscle hypertonicity either compressing nerves directly or causing postural changes that then result in compression by bony structures. Thoracic Outlet Syndrome is a condition that effects the nerves coming into the arm and is caused by compression between the scalene muscles in the neck and the first rib. Compression of the median nerve in the wrist will cause carpal tunnel syndrome. Radial, median and ulnar nerve entrapment are also caused by compression of muscles in the arm and a potential problem for musicians. If you suspect you may have one of these conditions get it checked out. The program will help with your rehabilitation but you need treatment.

What we know about CTD's

So while there are still lots of things that we don't know about Cumulative Trauma Disorders, and Overuse Injuries in particular, there are a few things that we do know.

The likelihood of injury is greater when the forces involved increase and when the limbs are positioned in other than a neutral position.
Muscles will shorten permanently when they are maintained in a short position for a length of time and to lengthen permanently when not being used over time in a phenomenon called creep.
Tissues generally, muscle tissue, connective tissue and nerve tissue, suffer from hypertrophy from excessive use and atrophy from inadequate use.

Risk factors?

Inadequate physical conditioning causes the sort of myofascial imbalances that are endemic in modern societies.
Playing with excessive tension from stress, poor technique, postural imbalance, or simply not warming up will damage you body.
Inadequate rehabilitation from previous injuries will compound new damage on top of old.