INTRODUCTION: Maintaining bone mineral density (BMD) is a crucial component of lifelong bone health and is particularly important for injury prevention in sport. Athletes participating in high impact sports have higher BMD compared to running athletes [1], underscoring the importance of mechanical loading in osteogenesis [2]. In contrast, cyclists and swimmers are at a greater risk for osteopenia due to low mechanical loading [3]. Currently, there is a dearth of information about BMD in triathletes, combining running, cycling and swimming. Given that aerobic fitness may influence the extent to which an athlete can generate osteogenic bone stress during training, the purpose of this study was to assess the relationship between submaximal and maximal oxygen uptake and BMD across endurance athletes involved in multiple activities vs. endurance running alone. METHODS: Triathletes (TA; n = 14, age = 38.4 ± 13.5 yrs, 7M:7F), training for an Ironman or similar event, and high-level marathoners (HLM; n = 14, age = 44.2 ± 17.3 yrs, 7M:7F), as determined by recent achievement of a Boston Marathon qualifying time, volunteered for this IRB-approved study. Dual energy x-ray absorptiometry (DEXA; Lunar iDXA; GE Healthcare, Chicago, IL) assessed total body, spine (L1-L4), and femoral neck BMD, which were converted to T-scores accordingly. An incremental treadmill protocol using a metabolic cart (Quark CPET; COSMED, Rome, Italy) recorded submaximal oxygen consumption (VO2) at participants` self-reported half-marathon race pace (RP) and maximal VO2 (VO2max) at maximal exertion. Independent t-tests were used to assess group differences. Simple bivariate correlations were assessed between each BMD measure and both RP and VO2max for both groups. ? was set p = 0.05. RESULTS: There were no differences between groups in VO2max, RP, or BMD (P > 0.05). RP VO2 was higher in HLM (45.5±7.3ml/kg/min) vs. TA (39.25 ± 6.2; p = 0.03). There were significant positive and moderate relationships between RP VO2 and femoral neck BMD (R2 = 0.29, p = 0.048) and total BMD (R2 = 0.32, p = 0.036) in the HLM group. These relationships were insignificant in the TA group (R2 = 0.03, p = 0.58; R2 = 0.003, p = 0.84). Trending correlations (p < 0.10) were seen between VO2max and BMD (FN, LS and total) in HLM, but not in TA participants. CONCLUSION: The results indicate that higher RP VO2 is related to greater BMD in HLM but not in TA. Since higher RP VO2 was strongly associated with greater speed at RP (p < 0.0001), this could facilitate increased accumulation of osteogenic bone stress during chronic training in HLM. Its possible that TA do not see the same changes in BMD with RP VO2 because of training regimen differences, but further investigation is needed. These findings provide a basis for future research to understand the complexities contributing to BMD in endurance athletes.
© Copyright 2022 27th Annual Congress of the European College of Sport Science (ECSS), Sevilla, 30. Aug - 2. Sep 2022. Julkaistu Tekijä Faculty of Sport Science - Universidad Pablo de Olavide. Kaikki oikeudet pidätetään. / Kääntänyt https://www.DeepL.com/Translator