Background. The factors that influence a successful return sport following Achilles tendon rupture repair have not been identified. Furthermore, the extent of heel-rise height index (HRHI) and Achilles tendon resting angle (ATRA) as indicators of Achilles tendon function recovery are unclear. Methods. We included 94 subjects who underwent a first unilateral Achilles tendon repair between 2017 and 2019, and returned to sports 9 months after surgery. Preoperative activity was set at 100 points, and subjects were classified into two groups with ≥ 80 points and < 80 points. Multiple logistic regression analysis was performed. The cutoff value of the extracted factors was also calculated. Dependent variables were patient background, extent of heel-rise height index (HRHI), and Achilles tendon resting angle (ATRA) for the unaffected side. Results. HRHI was only extracted as an influencing factor (odds ratio, 1.104)., with a cutoff value of 89.5%. The ATRA required for this HRHI was 72.4% as the cutoff value calculated. Conclusions. After Achilles tendon repair, the HRHI required for good sports activity. The HRHI was about 90%, ATRA required was 70% or more. It is necessary to prevent Achilles tendon elongation after surgery.