These results indicate that a fatigued athlete may have to increase the elongation

to absorb a given amount of energy and thus increased muscle strains in the movement and the risk for muscle strain injury. The study by Small et al.72 also provides support for fatigue as being a risk factor. They found that fatigue significantly increased the knee flexion angle at which peak knee eccentric flexion torque occurred. This result combined with the results of those Idelalisib solubility dmso studies on the general mechanism of muscle strain injury and optimum hamstring muscle length indicate that hamstring muscle strain may be increased in a given movement when fatigued. To a certain degree, this result also supports increasing hamstring flexibility as a prevention strategy for hamstring strain injury. Hamstring strain injury may be associated with low back pain in the zygapophyseal origin area.73 Mooney and Robertson74 found increased electrical activities and decreased flexibility of hamstring muscles for patients with low back pain. These results indicate that low back pain may provoke hamstring responses such as increased tension and result in muscle damage.73 In a retrospective study, Hennessey and Watson75 found a significant increase of lumbar lordosis among hamstring injured athletes in comparison buy AZD6244 to their

uninjured counterparts, which indicates a possible association between hamstring strain injury and lumbar posture. However, a study by Verrall et al.2 found that a past history of back injury did correlate with an increased risk of posterior thigh pain, which did not necessarily mean a hamstring strain injury. Abnormal neural tension was another proposed modifiable risk factor for the recurrence of hamstring strain injuries.76 Abnormal neural tension is defined as abnormal physiological and mechanical responses in the neuromuscular system when the normal range of movement and stretch capabilities no is exceeded.77 and 78

Neural tension can be evaluated using the Slump test.77 and 78 Branches of the sciatic nerve can be tethered to the scar after a hamstring injury, and create increased neural tension with or without local irritation, which may result in local damage to the hamstring muscle.73 Turl and George76 reported that more than 50% of athletes had abnormal neural tension after non-repetitive grade I hamstring strain injuries. However, as previous studies on the mechanism of muscle strain injury demonstrated, muscle strain injuries are caused by strain, not by force.35 and 36 As the relationship between muscle strain injury and abnormal neural tension is still speculative in nature, the relevance of incorporating special mobility techniques including “neural tension positions” in rehabilitation programs has not yet been scientifically established.