You have not written about the physiotherapy management of your patient. What management plan have you adopted so far?
A hamstrings strain is may be caused by a sudden high velocity movement seen in sprinters, hurdlers and high jumpers. Associated causative factors include poor flexibility, inadequate warm up, fatigue, and quadriceps/hamstring muscle imbalance.
It is treated with Ice and wrap and with ice and ultrasound. Once soreness is gone, progression is made to hamstring curls, high speed cycling and stretching ( including dural stretching ).