Enhanced Bone Size, Microarchitecture, and Strength in Female Runners with a History of Playing Multidirectional Sports

Abstract

Purpose: Female runners have high rates of bone stress injuries (BSIs), including stress reactions and fractures. The current study explored multidirectional sports (MDS) played when younger as a potential means of building stronger bones to reduce BSI risk in these athletes. Methods: Female collegiate-level cross-country runners were recruited into groups: 1) RUN: history of training and/or competing in cross-country, recreational running/jogging, swimming and/or cycling only and 2) RUN+MDS: additional prior history of training and/or competing in soccer or basketball. High-resolution peripheral quantitative computed tomography was used to assess the distal tibia, common BSI sites (diaphysis of the tibia, fibula and 2nd metatarsal), and high-risk BSI sites (base of the 2nd metatarsal, navicular and proximal diaphysis of the 5th metatarsal). Scans of the radius were used as control sites. Results: At the distal tibia, RUN+MDS (n=18) had enhanced cortical area (+17.1%) and thickness (+15.8%) and greater trabecular bone volume fraction (+14.6%) and thickness (+8.3%) compared to RUN (n=14) (all p<0.005). Failure load was 19.5% higher in RUN+MDS (p<0.001). The fibula diaphysis in RUN+MDS had 11.6% greater total area and 11.1% greater failure load (all p≤0.03). At the 2nd metatarsal diaphysis, total area in RUN+MDS was 10.4% larger with greater cortical area and thickness and 18.6% greater failure load (all p<0.05). RUN+MDS had greater trabecular thickness at the base of the 2nd metatarsal and navicular and greater cortical area and thickness at the proximal diaphysis of the 5th metatarsal (all p≤0.02). No differences were observed at the tibial diaphysis or radius. Conclusion: These findings support recommendations that athletes delay specialization in running and play MDS when younger to build a more robust skeleton and potentially prevent BSIs.