Background of The Study: Stress fractures refer to fractures occurring in the bone due to a mismatch of bone strength and chronic mechanical stress placed upon the bone. Stress fractures represent a spectrum of injuries ranging from periostitis, caused by inflammation of periosteum, to a complete stress fracture that includes a full cortical break. Prevalence of tibial stress fracture is greater in high impact activities like running sports. Some reports indicate that up to 20% of elite runners may suffer from some sort of stress fracture. Incidence in National Collegiate Athletic Association (NCCA) athletic populations is reported at around 5.7 stress fracture per 1,00,000 athletic encounters, although this rate is significantly higher in (>20/1,00,000). The tibia is implicated in between 20% and 60% of stress injuries, depending of the sport and level of play. Age- Tibial stress fracture often presents in young adults, active patients but may occur in patients of all age. Sex- evidence suggests that stress fracture common in females than males. Stress fracture is the most common injury occurs in athletes that leads to severe pain, swelling, limited mobility and reduced performance. The purpose of the study was Deep water running training and muscular endurance training showed improve running in post posterior tibial stress fracture in athlete. Objectives: The study’s primary objective was to find out the effectiveness of deep water running and muscular endurance training on running in athlete with post posterior tibial stress fracture Subjects And Methods: This is a single case study, in which a 17 year old male involved in high school athletics middle distance running had a history of pain for 3 weeks along with training. He was diagnosed with posterior tibial stress fracture. He had given the deep water running training and muscular endurance training. The pre and post- test values are taken using cooper’s test and University of Wisconsin Running Injury and Recovery Index (UWRI). The treatment duration was 8weeks. Result: The pre and post-test values was taken using University of Wisconsin Running and Recovery Index (UWRI) was 4 and 36. The 2nd week and post-test values of coopers test were 800m and 3000m.Hence, the statistical report states that there were significant increases of running capacity in an athlete with post posterior tibial stress fracture. Conclusion: Hence, it concluded that after 8 weeks of treatment there was statistically significant in the application of deep water running training and muscular endurance training in improving the running capacity in athlete with post posterior tibial stress fracture. Clinical Implication: Deep water running training and muscular endurance training are found to produce significant effect to manage running in athlete with post posterior tibial stress.