Musculotendinous (MT) injury and tendinopathy occur for a wide variety of reasons. The pathophysiology of injury and the principles of rehabilitation have been addressed by other authors of this text. This chapter focuses on what evidence exists for prevention of musculotendinous injury.

The clinician must be mindful that there are many variables that may interact to make a patient susceptible to the development of MT injury. In addition, the properties of the muscle, tendon and enthesis tissue vary widely, and the tissue mechanical characteristics will generally determine the type of injury sustained. Injury patterns can include a strain, a partial tear, an intra-substance tear, a complete disruption or a low-grade overuse inflammatory response.

Predicting MT injury with the goal of being able to prevent it is an imprecise science and relies on the skill, experience and intuition of the clinician. Such a prediction requires an awareness of the potential for injury and bringing together information relating to medical history (Lin et al. 2004) (Magnaris et al. 2004) medication use, comorbidities such as diabetes or inflammatory conditions, activity level, skill repetition and nature of activity, external environmental factors as well as intrinsic collagen qualities and physical biomechanical characteristics. It is beyond the scope of this chapter to explore each of these potential areas in detail; however, we will attempt to highlight known factors which should alert a clinician to the fact that damage to the MT unit may ensue. In addition, while many of the underlying principles discussed can be applied to many parts of the body, this chapter will restrict itself to lower limb injury.

Acute MT injuries classically result from a single tensile overload incident. Chronic injuries however result from repetitive excessively loaded events (Sandrey 2003) (Magnaris et al. 2004). It has been suggested that acute injuries may indicate the presence of a chronic pathology predisposing to the injury (Magnaris et al. 2004).

Historically, prevention of MT injury during sports participation has centred on stretching, strengthening and the preparticipation warm-up. This has developed to include specific exercises such as plyometrics, eccentric training and neuromuscular stretching among others along with the use of anatomical modifying aids such as orthotics, taping and bracing. An association between static stretching exercises and a reduced incidence of MT injuries were reported in college football players (Cross and Worrell 1999), and in a prospective cohort study of male soccer players, those with less hamstring flexibility were more likely to sustain a hamstring MT injury (Witvrouw et al. 2003). Many ailments associated with running can readily be explained by anatomy and biomechanics. Gallo et al. in a recent review (Gallo et al. 2012) found little evidence for stretching and conditioning for prevention of lower limb soft tissue running injuries. Overall, evidence that interventions could reduce lower limb pain and injury after intense running was considered weak. However, their continued use does not appear to cause harm and probably aids in athletic performance in many individuals and may therefore reduce risk of injury in some.

Genetic. It has been shown (Baumert et al. 2016) that certain gene variations, or polymorphisms, are associated with a propensity to exercise induced muscle soreness and possibly to an increased risk of delayed recovery or even of MT disruption. This knowledge may not benefit the majority of athletes but certainly could assist elite athletes in planning their training schedules to maximise recovery and reduce overload injuries.

Traumatic. It is known that concentric exercises can lead to an increased likelihood and degree of exercise-induced muscle damage (EIMD) and that this can be reduced by eccentric exercises. As it is known that EIMD may in turn predispose to MT injury, it is important that eccentric exercises be incorporated into a preparticipation exercise program. Concentric exercises enable strength and enhance joint stability, but most MT injuries occur during eccentric load, thus emphasising that eccentric exercises should form a part of a regular training session (Gleeson et al. 2003).

Fatigue has been implicated in many sports injuries. In English professional soccer, significantly more hamstring tears occur towards the end of both halves suggesting fatigue to be a factor (Woods et al. 2004). While muscles are injured at the same length, regardless of fatigue, fatigued muscles are less able to absorb energy, in eccentric load, before reaching the degree of elongation which causes the injury (Petersen and Holmich 2005). Thus, endurance training is an important factor in aiming to prevent MT injuries.

Dietary and Body Habitus. Apart from causing obesity, which is in itself a risk factor for MT injury, excessive intake of lipid can cause a dyslipidaemia which can weaken tendons biologically. This is a theoretical and uncommon problem but may be relevant in the elite athlete with altered lipid metabolism (Scott et al. 2015)

Patients with a body mass index (BMI) of 25 or more have an increased risk of Achilles or posterior tibial tendinopathy (Frey and Zamora 2007). Elevated BMI is also associated with MRI evidence of patellar tendon pathology (Scott et al. 2015). Rupture of the tibialis posterior tendon has been shown to be associated with hypertension, diabetes and obesity (Holmes and Mann 1992). Each of these conditions should be managed medically before the patient begins an activity which would risk developing a tendinopathy.