This study investigated effects of ankle dorsiflexion range and pre-exercise calf muscle stretching on relative risk of selected injuries in 1093 male Army recruits undertaking 12 weeks of intensive training. Prior to training, ankle dorsiflexion range was measured and recruits were allocated to stretch and control groups using a quasi-random procedure. The stretch group stretched calf muscles under supervision prior to all intense exercise. The control group stretched upper limb muscles instead. Forty-eight injuries were recorded. Survival analysis indicated that ankle dorsiflexion range was a strong predictor of injury (p = 0.03). Definitive evidence of an effect of stretching on injury risk was not found (p = 0.76), but the sample size may have been insufficient to detect such an effect.
Pope, R., Herbert, R., & Kirwan, J. (1998). Effects of ankle dorsiflexion range and pre-exercise calf muscle stretching on injury risk in Army recruits. Australian Journal of Physiotherapy, 44(3), 165–172. https://doi.org/10.1016/S0004-9514(14)60376-7