Training-induced Increase in Bone Mineral Density between Growing Male and Female Rats

Abstract

The purpose of this study was to determine the existence of sex differences in the resistance training-induced elevation in bone mineral density (BMD) and bone strength (Fmax) during the growth period in rats. 16 male (M) and 16 female (F) rats (approx. 8 weeks old) were randomly divided into sedentary control (MC=8, FC=8), and resistance-trained (RT) groups (M-RT=8, F-RT=8). The RT groups were conditioned to climb a vertical ladder 4 consecutive times (per exercise session) with weights attached to their tail 3 days per week for a total of 6 weeks. After 6 weeks, there were no interaction effects (sex×exercise). The main effect of sex indicated no difference in tibial BMD (in g/cm²) for males (0.226±0.005) compared to females (0.221±0.004). However, Fmax (in Newtons) was significantly greater for males (131.3±5.3) compared to females (89.9±3.0). The main effect of exercise indicated that tibial BMD and Fmax were significantly greater for RT groups (0.234±0.004 g/cm² and 120.9±7.4 Newtons) compared to controls (0.212±0.003 g/cm² and 100.3±5.1 Newtons). The results indicate that during growth, there were no sex differences in the training-induced elevation in BMD and bone mechanical properties.

Key words

tibia - DXA - bone strength - 3-point bending test

• References

• 1 Ahles CP, Singh H, Joo W, YLee Y, Lee LC, Colazas W, Pierce RA, Prakash A, Jaque SV, Sumida KD. High volumes of resistance exercise are not required for greater bone mineral density during growth. Med Sci Sports Exerc 2013; 45: 36-42
• 2 Bass SL, Saxon L, Daly RM, Turner CH, Robling AG, Seeman E, Stuckey S. The effect of mechanical loading on the size and shape of bone in pre-, peri-, and postpubertal girls: a study in tennis players. J Bone Min Res 2002; 17: 2274-2280
• 3 Bennell K, Page C, Khan K, Warmington S, Plant D, Thomas D, Palamara J, Williams D, Wark JD. Effects of resistance training on bone parameters in young and mature rats. Clin Exp Pharmacol Physiol 2000; 7: 88-94
• 4 Brinckmann P, Hoefert H, Jongen HT. Sex differences in the skeletal geometry of the human pelvis and hip joint. J Biochem 1981; 14: 427-430
• 5 Cardadeiro G, Baptista F, Ornelas R, Janz KF, Sardinha LB. Sex specific association of physical activity on proximal femur BMD in 9 to 10 year-old children. PLOS One 2012; 7: 1-7
• 6 Cawthon PM. Gender differences in osteoporosis and fractures. Clin Orthop Relat Res 2011; 469: 1900-1905
• 7 Daly RM. The effect of exercise on bone mass and structural geometry during growth. Med Sport Sci 2007; 51: 33-49
• 8 Danz AM, Zittermann A, Schiedermaier U, Klein K, Hotzel D, Schonau E. The effect of a specific strength-development exercise on bone mineral density in perimenopausal and postmenopausal women. J. Women Health 1998; 7: 701-709
• 9 Fredrik T, Detter L, Rosengren BE, Dencker M, Nilsson JA, Karlsson MK. A 5-year exercise program in pre- and peripubertal children improves bone mass and bone size without affecting fracture risk. Calcif Tissue Int 2013; 92: 385-393
• 10 Fujimura R, Ashizawa N, Watanabe M, Mukai N, Amagai H, Fukubayashi T, Hayashi K, Tokuyama K, Suzuki M. Effect of resistance exercise training on bone formation and resorption in young male subjects assessed by biomarkers of bone metabolism. J Bone Min Res 1997; 12: 656-662
• 11 Godfrey JK, Kayser BD, Gomez GV, Bennett J, Jaque SV, Sumida KD. Interrupted resistance training & BMD in growing rats. Int J Sports Med 2009; 30: 579-584
• 12 Goettsch BM, Smith MZ, O’Brien JA, Gomez GV, Jaque SV, Sumida KD. Interrupted vs. uninterrupted training on BMD during growth. Int J Sports Med 2008; 29: 980-986
• 13 Harriss DJ, Atkinson G. International Journal of Sports Medicine – Ethical Standards in Sport and Exercise Science Research. Int J Sports Med 2013; 34: 1025-1028
• 14 Honda A, Naota S, Nagasawa S, Kato T, Umemura Y. Bones benefits gained by mump training are preserved after detraining in young and adult rats. J Appl Physiol 2008; 105: 849-853
• 15 Hornberger TA, Farrar RP. Physiological hypertrophy of the FHL muscle following eight weeks progressive resistance exercise in the rat. Can J Appl Physiol 2004; 29: 16-31
• 16 Hoshi A, Watanabe H, Chiba M, Inaba Y. Bone density and mechanical properties in femoral bone of swim loaded aged mice. Biomed Environ Sci 1998; 11: 243-250
• 17 Jarvinen TL, Kannus P, Sievanen H. Have the DXA-based exercise studies seriously underestimated the effects of mechanical loading on bone?. J Bone Miner Res 1999; 14: 1634-1635
• 18 Johnston CC, Hui SL, Wiske P, Norton JA, Epstein S. Bone mass at maturity and subsequent rates of loss as determinants of osteoporosis. In Osteoporosis: Recent Advances in Pathogenesis and Treatment. Edited by DeLuca HF. University Park Press; Baltimore, MD: 1981. pp 285-291
• 19 Kayser BD, Godfrey JK, Cunningham R, Pierce RA, Jaque SV, Sumida KD. Equal BMD after daily or triweekly exercise in growing rats. Int J Sports Med 2010; 31: 44-50
• 20 Kriemler S, Zahner L, Puder JJ, Braun-Fahrlander C, Schindler C, Farpour-Lambert NJ, Kranzlin M, Rizzoli R. Weight-bearing bones are more sensitive to physical exercise in boys than in girls during pre- and early puberty: a cross-sectional study. Osteoporos Int 2008; 19: 1749-1758
• 21 Lowry OH, Rosebrough NJ, Farr AL, Randall RJ. Protein measurement with the Folin phenol reagent. J Biol Chem 1951; 193: 265-275
• 22 Menkes A, Mazel S, Redmond RA, Koffler K, Libanati CR, Gundberg CM, Zizic TM, Hagberg JM, Pratley RE, Hurley BF. Strength training increases regional bone mineral density and bone remodeling in middle-aged and older men. J Appl Physiol 1993; 74: 2478-2484
• 23 Mosley JR, Lanyon LE. Growth rate rather than gender determines the size of the adaptive response of the growing skeleton to mechanical strain. Bone 2002; 30: 314-319
• 24 Notomi T, Okimoto N, Okazaki Y, Tanaka Y, Nakamura T, Suzuki M. Effects of tower climbing exercise on bone mass, strength, and turnover in growing rats. J Bone Min Res 2001; 16: 166-174
• 25 Pierce RA., Cunningham RM, Shdo SM, Ahles CP, Lee LC, Jaque SV, Sumida KD. Different training volumes yield equivalent increases in BMD. Int J Sports Med 2010; 31: 803-809
• 26 Seeman E. Periosteal bone formation – a neglected determinant of bone strength. NEJM 2003; 349: 320-323
• 27 Smith MZ, Goettsch BM, O’Brien JA, Van Ramshorst RD, Jaque SV, Sumida KD. Resistance training & bone mineral density during growth. Int J Sports Med 2008; 29: 316-321
• 28 Sundberg M, Gardsell P, Johnell O, Karlsson MK, Ornstein E, Sandstedt B, Sernbo I. Peripubertal moderate exercise increases bone mass in boys but not in girls: a population-based intervention study. Osteoporos Int 2001; 12: 230-238
• 29 Suominen H. Muscle training for bone strength. Aging Clin Exp Res 2006; 18: 85-93
• 30 Umemura Y, Seigo N, Naota S, Honda A. Effects of jump training on bone are preserved after detraining, regardless of estrogen secretion state in rats. J Appl Physiol 2008; 104: 1116-1120
• 31 Warden SJ, Fuchs RK, Castillo AB, Nelson IR, Turner CH. Exercise when young provides lifelong benefits to bone structure and strength. J Bone Min Res 2006; 22: 251-259
• 32 Weeks BK, Young CM, Beck BR. Eight months of regular in-school jumping improves indices of bone strength in adolescent boys and girls: the POWER PE study. J Bone Min Res 2008; 23: 1002-1011
• 33 Welten DC, Kemper HCG, Post BG, Van Mechelen W, Twisk J, Lips P, Teule GJ. Weight-bearing activity during youth is a more important factor for peak bone mass than calcium intake. J Bone Miner Res 1994; 9: 1089-1096