The Effects of 10 Weeks Military Training on Heel Ultrasound and Bone Turnover

Abstract

To measure the physiological changes in bone in response to strenuous exercise we performed a prospective study of male army recruits over 10 weeks of basic training. Measurements performed at the start and completion of training consisted of ultrasound (US) measurements of the heel: velocity of sound (VOS in m/seconds) and broadband ultrasound attenuation (BUA in dB/MHz) and bone turnover markers; osteocalcin (OC), bone-specific alkaline phosphatase (BALP), and tartrate-resistant acid phosphatase (TRAP). Forty subjects were recruited for the study and 26 completed training. Over the 10-week study period there was a significant 1.7% fall in mean VOS [mean paired difference (mpd) 27.2 m/second, SEM 9.5 (95% CI 7.5-46.8) P = 0.009] and a nonsignificant 3.4% increase in BUA (P = 0.159). There were significant falls in markers of bone formation OC [11.6%, mpd 0. 11 microg/liter (95% CI 0.07-0.14) P < 0.001] and BALP [13.3%, mpd 3. 49 U/liter (CI 0.80-6.18) P = 0.013] and a nonsignificant 9.5% fall in TRAP a marker of bone resorption. The 10 recruits subsequently injured had a significantly lower VOS on entry [mean difference 24.2 m/seconds (95% CI 4.6-43.7) P = 0.017] and nonsignificantly raised BUA and baseline levels of all bone markers. The ultrasound changes may be accounted for by increase in trabecular separation and a fall in trabecular connectivity due to microfracture. The decrease in bone markers implies a fall in bone turnover.

Relationship between calcaneal quantitative ultrasound and hip dual energy X-ray absorptiometry in young healthy men

“…It has been previously applied to a smaller study of UK army recruits [34]. Manufacturer's protocol was followed for foot positioning, insert selection and acoustic coupling of the transducers to skin with ultrasound gel.…”

Cortical bone resorption during exercise is interleukin-6 genotype-dependent

“…They are of similar age, can be selected to be of the same race and sex, and are exposed to similar dietary and environmental conditions whilst undergoing an identical 10-week programme of physical training. Markers of bone formation are already known to fall significantly over the training period (Etherington et al 1999). If IL-6 does indeed mediate exercise-related bone resorption, then the IL-6 'G' allele should be associated with increased bone resorption/reduced bone deposition when compared to the 'C' allele.…”

Increased density and periosteal expansion of the tibia in young adult men following short-term arduous training

“…Twelve weeks of initial military training, characterised by variable, dynamic and high impact activities, increased bone volume and whole bone cross sectional area of the femur in male recruits [25]. Other military training interventions have shown decreased areal BMD at the lumbar spine [14] and increased trabecular separation at the calcaneus [26], suggesting that early adaptations to exercise are site-specific, localised to sites of highest loading [27,28].…”