Hamstring strain injury is the most common noncon-tact muscle injury for soccer players, representing twothirds of thigh muscle strains [1]. Hamstring strain injury and recurrence rate were high in the past three decades.Objective To investigate the effect of adding Nordic exercise as post-training in decreasing hamstring initial, recurrent injuries rates, and their severity. Methods In this randomly controlled trial study, 34 professional football players aged 21 to 35 years were randomly assigned into two groups (17 players each) from Sporting clubs at Alexandria, Egypt. For group one, Nordic hamstring exercise (NHE) was performed pre-training and post-training. For group two, NHE was only performed pre-training. The control group was the same team during the previous season. Length of the trial was 12 weeks. The Australian football association injury form was used to collect incidence of injuries for each subject in both groups. Results Pooled results based on total injuries showed that group one had significantly less hamstring initial injuries (92% less) than the previous season, while group two had 80% less initial injuries and 85% less recurrent injuries than previous season. Regarding the severity of injuries in term of mean number of absent days, it was 1 day for group one and 2.7 days for group two while it was 7.95 days for the previous season during total risk time of 116.3±13.2 and 117.6±5.7 exposure hours for group one and group two, respectively. Conclusion The use of NHE as a prevention protocol was effective in reducing all hamstring injuries with the use of NHE during pre-training and post-training having the greatest effect. ORCID: Ahmed Ebrahim Elerian (https://orcid.org/0000-0003-3335-8933); Mohsen M. El-Sayyad (https://orcid.org/0000-0002-2230-3067); Hend Adel Abdelhalim Dorgham (https://orcid.org/0000-0001-7245-5336).