yogabook / movement physiology / muscle injuries

Muscle and tendon injuries account for between 10% and 55% of all injuries that occur in sport. Basically, they can mean longer periods of absence or even the end of an athlete’s career, especially if they have not been adequately treated. Prophylactically, warming up the musculoskeletal system and the environmental conditions are very important: cold and wet conditions have many disadvantages and risks for the musculoskeletal system. Typical high-risk situations for muscles are sudden eccentric contraction and the change from sudden eccentric contraction to concentric contraction, as is the case when jumping again after coming up from a jump. Muscular fatigue and loss of movement coordination are also significant risk factors, which is why many injuries in team sports occur in the last third of the competition. Warm-up exercises are extremely important, but performed incorrectly they can also pose a risk. Warming up the muscle leads, among other things, to the provision of performance-adequate blood flow, which would only occur with a corresponding delay without warming up. Biarticular muscles are affected by injuries far more frequently than monoarticular muscles. Insufficiently healed muscle contusions also represent predilection sites for further injuries at the boundary between scar tissue and muscle tissue due to differences in elasticity.

In the case of muscle injuries, a distinction must be made between injuries at the point of attachment to the bone, injuries in the course of the tendon itself, injuries to the muscle-tendon junction and injuries to the muscle belly. Muscle injuries can be divided into three types: firstly, overstretching/strain or tearing, affecting a maximum of 5% of the fibers, secondly, interruption of continuity of more than 5% of the fibers and thirdly, complete tearing with corresponding loss of function. The tearing of muscle fibers necessarily results in a hematoma. Since the blood throughput of a muscle increases by a factor of up to 2.5 under load, muscle fiber tears during sporting activity lead to a much more pronounced hematoma than would be the case at rest. Impact trauma against a tensed muscle usually leads to superficial injuries and hematomas. If relaxed muscles suffer trauma, the injuries and hematomas are usually deep and close to the bone, which can lead to extraosseous calcifications. There is also a third type of hematoma, which can occur in the connective tissue layer between muscles.

Injury types 1 and 2 usually show no pain at rest, type 3 at the latest a pronounced hematoma with corresponding pressure pain and possibly tension pain, as well as often a painful hypertonicity. Diagnostically, sonography can be used to assess the extent of the hematoma, the type of injury and the muscle structure. During sonography, a hematoma can be punctured and an intramuscular injection can be made, and muscle function can be observed in situ. A contrast MRI shows injuries to the muscles and tendons very well, but is used less frequently in acute cases than in chronic cases or insertional tendinopathy and also offers the possibility of examining bone injuries caused by trauma or detecting extraosseous calcifications. Scintigraphy is available as a final diagnostic tool, particularly in cases of suspected insertional tendinopathy.

Immediate intervention for recent muscle injuries is carried out according to the PECH scheme to minimize haematoma formation and thus the expected connective tissue scar. A pressure cuff can be used to reduce blood flow and the muscle is cooled every 20 minutes. Elevating the extremity helps to reduce the blood pressure at the site of the injury. The hematoma should not spread any further after 24 hours at the latest. During this time, the event should be observed to rule out the consequences of a compartment syndrome that is discovered too late. Muscle relaxants can be administered during this time. Once the formation of the hematoma is complete, i.e. after 24 hours, the hematoma can be punctured under ultrasound control to promote healing. This can be done several times in succession if necessary. Even after more than 72 hours, the hematoma can coagulate, which requires intervention, preferably by re-liquefaction and aspiration under sonographic control. In more pronounced cases, an ultrasound should be performed every 2-3 days to detect and treat recurrent bleeding. Musculoskeletal strain should be avoided for the first few days; at best, movement exercises without load can be performed. After a week, you can start to gradually increase the load, whereby the occurrence of pain indicates the load limit.

Stretching exercises are only indicated from the second week after the event and should generally be performed bilaterally. Well-dosed cyclical movement patterns without shock-like load peaks such as cycling can be resumed from the third week onwards. Sport-specific training can only be resumed from the fourth week onwards, where in the first two weeks of supervised adapted training NSAIDs and muscle relaxants may be used. Cooling can be used after exercise. The first stretching massages to the site of the injury may be carried out at the earliest two weeks after the event. In the case of type 3 injuries, surgical intervention should be performed within 48 hours if possible. In the case of very pronounced muscle fiber tears, the muscle should be sutured, which promotes regeneration and leads to a greater achievable maximum force after healing than without sutures, in animal experiments 80% of the contralateral force. A poor prognosis results from immobilization with a plaster cast, as this results in pronounced areas of connective tissue. After the surgical intervention, the muscle must be immobilized and relieved for 7 days, after which it is decided after ultrasound when rehabilitation can begin. The question of whether a muscle has significant synergists deserves particular attention and can help decide whether surgery is indicated.

In principle, the regeneration time of muscle fibers is three weeks, but in the case of complete ruptures, regeneration will be between twice and four times as long. The hematomas that occur when muscles fibres are torn significantly delay healing. The inflammatory process by which the muscle repairs itself begins in the first minute after the trauma. The formation of non-functional scar tissue begins two weeks after the trauma and is completed after a further four weeks. To accelerate healing, various tissue growth factors can be injected into the injured area in the case of severe injuries.