The Role of Fatigue in Susceptibility to Acute Muscle Strain Injury

Abstract

We investigated the role of fatigue in muscle strain injuries using the extensor digitorum longus muscles of 48 rabbits. The muscles of the rabbits were fatigued by 25% or 50% then stretched to failure and compared with the contralateral controls. Three rates of stretch were used. The force to muscle failure was reduced in the fatigued leg in all groups (range, 93% to 97.4% compared with the controls). The change in muscle length in the fatigue groups was not different from the controls. The amount of energy absorbed in the fatigued muscle was 69.7% to 92% that of the energy absorbed in the control muscle. The lowest energy absorption occurred in muscles that were more fatigued. In eight additional rabbits, fatigued extensor digitorum longus muscles were compared with submaximally stimulated muscles with the equivalent contractile properties, and no difference was seen. Muscles subjected to strains are frequently injured under high-intensity eccentric loading conditions. Under these conditions, muscles absorb energy and provide control and regulation of limb movement. Our data showed that muscles are injured at the same length, regardless of the effects of fatigue. However, fatigued muscles are able to absorb less energy before reaching the degree of stretch that causes injuries.

Epidemiology of Quadriceps Strains in National Collegiate Athletic Association Athletes, 2009–2010 Through 2014–2015

“…4 Also, competition often features stronger muscle contractions coupled with greater fatigue relative to practice settings, thereby placing athletes at greater risk for muscle strains. 10,21 However, nearly 4 times as many quadriceps strains were reported in practices than in competitions, which is most likely the result of far larger numbers of practices than competitions across a season. In both practice and competition settings, athletes should take the time to perform an active warm-up before activity and conclude with postactivity stretching to decrease the risk of injury associated with stiffness and length asymmetries.…”

“…It is also common for athletes to experience the greatest total training volume during the preseason, which may cause fatigue that places athletes at greater risk for strains. 10,21 Injury Mechanism…”

Effects of Taping on Wrist Extensor Force and Joint Position Reproduction Sense of Subjects With and Without Lateral Epicondylitis

“…Sustained loading may increase strain on the injured soft tissues, promoting muscle fatigue 7) . A fatigued muscletendon unit is more susceptible to stretch injury, resulting in a predisposition to LE 11) .…”

An Acute Bout of Static Stretching Does Not Affect Maximal Eccentric Isokinetic Peak Torque, the Joint Angle at Peak Torque, Mean Power, Electromyography, or Mechanomyography

“…22,49 Two reviews suggested that stretching before strenuous exercises may increase the risk of injury. 44,51 Based on the suggestion by Mair and colleagues 30 that a muscle's ability to absorb eccentric energy is critical to avoid injury, Shrier 44 hypothesized that, if stretching reduced eccentric muscle strength, the muscle may be predisposed to strain-related injuries because it would not be able to prevent excessive sarcomere lengthening. To our knowledge, only 1 previous study 12 tested this hypothesis, and the authors concluded that static stretching did not affect eccentric torque production in women.…”