Kinanthropometric profile, hip bone mineral density, and the incidence of bone stress fractures in professional middle and long-distance runners

Purpose: This study aimed to identify the kinanthropometric profile, hip bone mineral density (BMD), and frequency of
bone stress fracture (BSF) in professional middle-distance and long-distance runners.

Methods:Thirty-seven professional male runners participated: middle-distance runners and long-distance runners aged
23.6 ± 2.6 years with over 6 years of training experience. Kinanthropometric measurements were performed according
to ISAK standards, including body composition and Heath-Carter somatotype assessment (endomorphy, mesomorphy,
ectomorphy). Hip BMD, bone mineral content (BMC), and T-scores were measured using DXA at the total and femoral neck
(FN) and trochanter (TR) regions. BSF history was collected through face-to-face interviews and medical records. Body Mass
Index (BMI) was calculated.

Results: Middle-distance runners presented superior all bone parameters (large effect: > .8). Long-distance runners have the
highest frequency of fracture incidence compared to middle-distance runners (68.5% vs 66.5%). The results of covariance
analyses showed that BMD FN was significantly influenced by muscle mass (kg) and endomorphy (scores) (adj. R2 = .56).
The same effect of these two variables was noted on the T-score FN (adj. R2 = .75). In turn, BMC FN was affected by the type
of sports competition, muscle mass (kg), and endomorphy (scores) (adj. R2 = .84). BMD TR was significantly influenced by:
endomorphy (scores) and mesomorphy (scores) (adj. R2 = .78). BMC TR was significantly affected by muscle mass (kg) (adj.
R2 = .75). In turn, T-score TR was influenced by muscle mass (kg), endomorphy (scores), and mesomorphy (scores) (adj. R2
= .68).

Conclusions: This study demonstrated that the type of athletic training and body tissue composition had a significant impact
on BMD in the hip region. The type and specificity of training in middle-distance runners had a more favourable effect
on bone parameters compared to long-distance runners. This relationship may be related to the greater mechanical load
resulting from greater muscle mass and more intense osteogenic stimuli.

The study analyzes the impact of athletic training on bone health in runners.