Sex Differences and Extracorporeal Shockwave Therapy Outcomes in Runners with Achilles or Hamstring Tendinopathy

Background/Objectives: Achilles and hamstring tendinopathies are common injuries in runners, and extracorporeal shockwave therapy (ESWT) may be an effective treatment. Runners are at risk for lower extremity tendinopathies and the Male and Female Athlete Triad (Triad). The purpose of this study is to evaluate the association of sex, exposure to hormonal contraceptives, menopause, and Triad-related risk factors with ESWT outcomes in the treatment of Achilles and hamstring tendinopathy. Methods: This is a retrospective cohort study of runners with either Achilles or hamstring tendinopathy who received radial or combined radial and focused ESWT. Tendon function was measured using Victorian Institute of Sport Assessment (VISA) questionnaires completed before and following treatment. Treatment success was defined by a change in VISA score that met the minimal clinically important difference (MCID). Results: There were 88 runners (54.5% female, 45.5% male) with Achilles (52.3%) or hamstring (47.7%) tendinopathy. No measurable difference was found in the proportion of females and males overall that achieved the MCID (57.1% and 72.5%, p = 0.17). Similar rates of females and males met MCID for Achilles (77.8% and 75.0%, p = 0.83) and hamstring tendinopathy (46.7% and 66.7%, p = 0.24). However, females with Achilles or hamstring tendinopathy who used oral contraceptive pills (OCPs) were less likely to meet the MCID compared to females not on OCPs (p = 0.031); this finding was present in a subgroup analysis of runners with only Achilles tendinopathy (p = 0.025). No associations were found between achieving the MCID and Triad risk factors, including body mass index, energy availability, weight-related behaviors, bone health, or menstrual function (all p > 0.05). Conclusions: Female and male runners reported similar success rates for ESWT, and Triad risk factors were not found to impact outcomes. However, females who used oral contraceptive pills were less likely to achieve the MCID from ESWT.