The Study Group (SG) had history and diagnosis of hamstring injury assessment with diagnosis image technique (ultrasound or MRI), and at least 2 of the next criteria: 1. When the injury happened disability to practise with the team at least one week; 2. Lost at least one match; 3. Felt pain when trying to kick the ball or run fast; 4. Receive specific treatment (medical or physiotherapy) for the injury; 5. Needed a period plan to return to play.