Article

Influence of exercise mode and osteogenic index on bone biomarker responses during short-term physical training.

Military Performance Division, U.S. Army Research Institute of Environmental Medicine, Building 42, Kansas Street, Natick, MA 01760, USA.
Bone (Impact Factor: 4.46). 06/2009; 45(4):768-76. DOI: 10.1016/j.bone.2009.06.001
Source: PubMed

ABSTRACT Prescribing exercise based on intensity, frequency, and duration of loading may maximize osteogenic responses in bone, but a model of the osteogenic potential of exercise has not been established in humans. In rodents, an osteogenic index (OI) has been used to predict the osteogenic potential of exercise. The current study sought to determine whether aerobic, resistance, or combined aerobic and resistance exercise programs conducted over eight weeks and compared to a control group could produce changes in biochemical markers of bone turnover indicative of bone formation. We further sought to determine whether an OI could be calculated for each of these programs that would reflect observed biochemical changes. We collected serum biomarkers [bone-specific alkaline phosphatase (BAP), osteocalcin, tartrate-resistant acid phosphatase (TRAP), C-terminal telopeptide fragment of type I collagen (CTx), deoxypyridinoline (DPD), 25-hydroxy vitamin D (25(OH)D), and parathyroid hormone (PTH)] in 56 women (20.3+/-1.8 years) before, during and after eight weeks of training. We also measured bone mineral density (BMD) at regional areas of interest using DXA and pQCT. Biomarkers of bone formation (BAP and osteocalcin) increased in the Resistance and Combined groups (p<0.05), while biomarkers of bone resorption (TRAP and DPD) decreased and increased, respectively, after training (p<0.05) in all groups. Small changes in volumetric and areal BMD (p<0.05) were observed in the distal tibia in the Aerobic and Combined groups, respectively. Mean weekly OIs were 16.0+/-1.9, 20.6+/-2.2, and 36.9+/-5.2 for the Resistance, Aerobic, and Combined groups, respectively. The calculated osteogenic potential of our programs did not correlate with the observed changes in biomarkers of bone turnover. The results of the present study demonstrate that participation in an eight week physical training program that incorporates a resistance component by previously inactive young women results in alterations in biomarkers of bone remodeling indicative of increased formation without substantial alterations in markers of resorption.

0 Bookmarks
 · 
108 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background We investigated the effects of demographic, lifestyle (self-reported smoking status and physical activity levels), cancer-related treatment factors (radiation and chemotherapy), and diet (calcium and vitamin D intake) on bone turnover and the relationship of bone turnover to lumbar spine bone mineral density (BMD) Z-scores (LS-BMD Z-scores) determined by quantitative computed tomography (QCT) in 418 ≥5-year survivors of childhood acute lymphoblastic leukemia (ALL).ProcedureBone turnover was assessed by biomarkers including serum bone-specific alkaline phosphatase (BALP), osteocalcin (OC), and urinary N-telopeptide of type I collagen indexed to creatinine (NTX/Cr). The 215 males ranged in age from 9 to 36 years (median age 17 years).ResultsAge and tanner score were inversely associated with all biomarkers (BALP, OC, NTX/Cr) (P < 0.001). Males had higher BALP and OC than females (P < 0.001). Body mass index (BMI) was inversely associated with OC and NTX/Cr (P < 0.001). There was no significant association of biomarkers with lifestyle related factors, ALL treatment-related factors, dietary calcium, vitamin D, or LS-BMD Z-score.Conclusions In this population of long-term survivors of ALL, bone turnover was significantly associated with age, gender, tanner stage, and BMI. ALL-related treatments did not influence bone turnover and bone turnover was not predictive of volumetric LS-BMD Z-score. Pediatr Blood Cancer © 2014 Wiley Periodicals, Inc.
    Pediatric Blood & Cancer 03/2014; · 2.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Weight-bearing activity has been shown to increase bone mineral density. Our purpose was to measure vertical ground reaction forces (GRFs) during cyclocross-specific activities and compute their osteogenic index (OI). Twenty-five healthy cyclocross athletes participated. GRF was measured using pressure-sensitive insoles during seated and standing cycling and four cyclocross-specific activities: barrier flat, barrier uphill, uphill run-up, downhill run-up. Peak and mean GRF values, according to bodyweight, were determined for each activity. OI was computed using peak GRF and number of loading cycles. GRF and OI were compared across activities using repeated-measures ANOVA. Number of loading cycles per activity was 6(1) for barrier flat, 8(1) barrier uphill, 7(1) uphill run-up, 12(3) downhill run-up. All activities had significantly (P < 0.01) higher peak GRF, mean GRF values and OI when compared to both seated and standing cycling. The barrier flat condition (P < 0.01) had highest peak (2.9 times bodyweight) and mean GRF values (2.3 times bodyweight). Downhill run-up (P < 0.01) had the highest OI (6.5). GRF generated during the barrier flat activity is similar in magnitude to reported GRFs during running and hopping. Because cyclocross involves weight bearing components, it may be more beneficial to bone health than seated road cycling.
    Journal of Sports Sciences 03/2014; · 2.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study assessed the osteogenic effect (T-Score) and changes in bone markers in healthy subjects by 12-weeks of aerobic training.
    Pakistan Journal of Medical Sciences Online 07/2014; 30(4):840-4. · 0.10 Impact Factor