Cartilage Metabolism and Bone Resorption in Ultramarathon Athletes

Ultramarathon running is becoming more popular, but its effects on bone and joint health are unclear. PURPOSE: To learn more about effects of ultramarathon running on biomarkers of bone and joint health. METHODS: 15 individuals (11 Male, 4 Female; Age = 38 ± 7 years; Mass = 66.9 ± 9.8 kg; Finish time = 28:54:53 ± 3:43:23; Weekly Miles in training = 53 ± 16.3 Miles) provided urine samples immediately before and after the Bear 100-mile Ultramarathon Race. Urine samples were frozen until assay analysis to determine concentrations for nTX (bone resorption marker) and uCTX-II (cartilage metabolism marker). Creatinine concentrations were also quantified and used to normalize the nTX and uCTX-II biomarkers. nTX and uCTX-II concentrations were compared between pre- and post-race for each subject using a paired t test (α = 0.05). This study was approved by the appropriate IRB and permission was given by participants to use the urine samples. RESULTS: nTX significantly (p = 0.045) increased from pre- (0.86 ± 1.06 nM BCE · mM-1 Creatinine) to post-run (4.79 ± 7.37 nM BCE · mM-1 Creatinine). uCTX-II also significantly (p < 0.001) increased from pre- (2.22 ± 5.78 nM BCE · mM-1 Creatinine) to post-run (4.64 ± 6.74 nM BCE · mM-1 Creatinine). CONCLUSION: These findings demonstrate that bone resorption and cartilage metabolism increase due to participation in an ultramarathon race. While we are unsure whether these concentration changes indicate beneficial or harmful changes to bone and cartilage, respectively, these results can serve as useful benchmarks in future studies. For example, studies of able-bodied individuals and/or individuals suffering from bone and/or joint disease who desire to continue participating in physical activity, including ultramarathon running.