In Developing Countries the Incidence of Osteoporosis Is Increasing at a Rate Faster Than

1 Improving Bone Density | 1 2 1Article Type: Commentary

3Article Category: Sports Fitness and Health

5Title: Training to Improve Bone Density in Adults: A Review and Recommendations

7Running Head: Improving Bone Density

9Authors: Ed McNeely

11Corresponding Author:

12Ed McNeely, MS

13One Academy Drive

14Daphne Al, 36526

[email protected]

16555-555-5555

18Ed McNeely is the senior physiologist at the Peak Centre for Human Performance and a partner

19in StrengthPro Inc. a Las Vegas based sport and fitness consulting company he is also a National

20Faculty member of the United States Sports Academy

24 3 Improving Bone Density | 2 4 25Training to Improve Bone Density in Adults: A Review and Recommendations

47 5 Improving Bone Density | 3 6 48ABSTRACT

49 The loss of bone density is becoming a major health concern in industrialized

50societies. Increasing bone density during puberty and young adulthood is considered the

51best option for preventing the negative health consequences associated with osteoporosis,

52even in middle aged and older adults an exercise program can increase bone density.

53While low volume impact oriented aerobic activities like running have been shown to be

54effective at increasing bone density excessive endurance training has been linked to low

55bone density. Strength training remains the best option for adults wishing to increase

56bone density. A regular program of high load (60-85% 1RM) training three or more times

57per week using a variety of exercises that challenge all major muscles has been shown to

58significantly increase bone density even in elderly adults.

60Key words: bone density, exercise, osteoporosis, training

72 7 Improving Bone Density | 4 8 73INTRODUCTION

74 Osteoporosis, which has been defined as bone mineral density (BMD) more than 2.5

75standard deviations below the young adult mean value (14), is a growing health problem for both

76men and women. In developed and developing countries the incidence of osteoporosis is

77increasing at a rate faster than what would be predicted by the aging of the population alone (15).

78In the U.S. It has been estimated that by 2025 the number of hip fractures attributed to

79osteoporosis will double to nearly 2.6 million with a greater percentage increase in men than in

80women (12).

81 Epidemiological evidence suggests that genetic factors are the most important cause of

82osteoporosis (20) and can account for as much as 80% of the variability in bone density in the

83population (6) but a variety of environmental factors have been linked to bone density including:

84negative energy balance, low calcium intake, lack of fruit and vegetable consumption, low body

85mass index, strength, and hormone levels (13,22,9,7,23), all of which may influence the ability to

86develop or maintain bone density.

87 A well designed exercise can have a tremendous impact on bone, increasing density, size

88and mechanical strength (23) and may be one of the keys to preventing complications associated

89with osteoporosis. If bone density and maximum tensile strength are increased before

90osteoporosis sets in, subsequent complications could be minimized (21). Unfortunately many

91adults wait to start an exercise program once they are diagnosed with low bone density.

92 For middle aged and older adults one of the primary health goals of an exercise program

93is to maintain bone density. Without an exercise intervention, after the age of 40 bone mass

94decreases by about 0.5% per year, regardless of sex or ethnicity (15). Whether appreciable

95increases in bone density can occur for this age group is equivocal (15) and dependant on the

96duration of the exercise program, age, dietary factors, and history of physical activity. A variety

97of different types of exercise have been used in bone building programs middle aged or older

98adults. 9 Improving Bone Density | 5 10 99Training Techniques

100Strength training

101 Although not all studies have shown improvement in bone density with strength training

102(15), strength training, if done with a high enough intensity for a prolonged period of time, seems

103to be effective for improving bone density in middle aged and older women who have low bone

104density (16). Programs that have been successful at increasing bone density have several common

105characteristics; training intensity above 70% 1RM, programs that last more than 12 months, and

106training frequency greater than two times per week.

108Endurance Training

109 Endurance training can be an acceptable form of exercise for maintaining or increasing

110bone density in middle aged or older adults provided there is sufficient impact. Stuart and Hannan

111(22) examined the effects of cycling, running or both on bone density in recreational male

112athletes. They found that runners had greater total and leg BMD than controls, those athletes

113participating in both cycling and running had greater total and arm BMD whereas the cyclists had

114decreased spine BMD compared to controls. The lack of impact involved in cycling may explain

115the lack of change in BMD even though all groups performed equal volumes of work throughout

116the study period. Walking programs, because of their low impact, tend to show only modest or no

117effects on BMD (3,18). Rowing because of the high compressive and shear forces placed on the

118spine, 4.6 times body weight, has been shown to increase lumbar spine BMD but not at other

119areas (17). Moderate training volumes seem to be more effective for increasing bone density.

120Running mileage of 20-30 km per week has a positive effect on bone, particularly lower leg and

121distal femur, but training volumes greater than this may cause a chronic increase in cortisol that

122negatively impacts bone (4) and running 92 km per week has been shown to result in bone

123density lower than sedentary controls (2).

124 11 Improving Bone Density | 6 12 125Jump Training

126 Although effective and popular in school based programs for increasing bone density in

127younger people jump training does not appear to be as effective in middle aged and older women.

128In a study comparing the effects of 12 months of vertical jumping on spine and proximal femur

129BMD in a group of pre and post menopausal women, Bassey, Rothwell, Littlewood and Pye

130(1998) found that 50 jumps six days per week increased BMD in the pre-menopausal group but

131not in the post menopausal group compared to group specific controls. Interestingly, the lack of

132change occurred even though the ground reaction forces and rate of force development on landing

133were higher in the post menopausal group resulting in a greater strain overload than in the pre

134menopausal group.

135 While a variety of exercise modalities have proven to be effective at maintaining bone

136density in adults there some basic principals should be considered when designing a long term

137program for people with osteoporosis:

139Exercise Considerations

140Use a progressive program

141 Increase resistance and intensity progressively. This is necessary because for bone to

142form it requires a minimum amount of strain. Once a bone adapts to a given strain level, the

143stimulus for bone to form is removed and a higher strain level becomes necessary for it to adapt

144further (10).

146Use dynamic movements

147 Mechanical loading of bone has an osteogenic effect only if the loading is dynamic and

148variable, static loading of bone does not trigger an adaptive response (23). Impact and rapid

149changes of direction can be particularly effective because ground reaction forces tend to be

150highest during these activities. Jumps, running, and more explosive or dynamic strength training 13 Improving Bone Density | 7 14 151activities should make up the majority of exercise in a bone building program. In adults with

152advanced osteoporosis more explosive exercises should be phased in gradually as their

153conditioning and bone strength improves.

155Vary the exercises

156 Bone adaptations occur primarily at insertion and origin points where muscles attach to

157the bones. Ryan et al. (1994) suggest that increased BMD from strength training and explosive

158activities is related to the load placed on the muscles that act as prime movers. A wide variety of

159exercises, which change every 2-4 weeks, exercising the whole body will help ensure that all

160bones receive stimulus to increase BMC or BMD.

162Minimum intensity

163 As with most training there is a minimum level of intensity that is needed to stimulate

164increase in BMD. For strength training activities there is a linear relationship between weight

165lifted and improvements in bone density (5) Chilibeck, Sale and Webber (1995) suggest that for

166strength training intensities of at least 60% 1RM are needed to increase BMD, with faster and

167greater increases in bone density coming as intensity climbs (16). For impact activities like

168running and jumping ground reaction forces of greater than two times body weight can increase

169bone density with higher forces having a greater effect.

171Training frequency

172 Improvements in BMD can occur with relatively short training sessions if high impact

173activities like jumping are the core of the program. However, there is a need to perform these

174sessions frequently. Studies of jump training have found that where three or more sessions per

175week is sufficient to increase bone two session per week has negligible effect on bone density

176(11). 15 Improving Bone Density | 8 16 177

178Program duration

179 Consistency is one of the keys to long term bone health. Like other tissues bone

180undergoes both adaptation to training and detraining during periods of decreased activity. The

181bone remodelling cycle lasts four to six months (8); this is the minimum period of time needed

182for BMD to change significantly. Training programs need to be designed so that they offer the

183variety and adaptability for people to make them a year round part of lifelong fitness regime.

185CONCLUSIONS

186 Decreased bone density is a growing problem in modern societies. Exercise remains one

187of the most potent alternatives to drug treatments for maintaining or improving bone density. An

188intensive program, three or more times per week featuring a variety of exercises, that considers

189the individual needs of each person and promotes long term compliance, can have a positive

190impact on bone density.

192APPLICATIONS IN SPORT

193 Over the past years adults have become more and more active in age group sports,

194particularly in the endurance sports like running, cycling and triathlon. The inclusion of an

195intensive strength training program will not only improve their performance but help offset the

196decrease in bone density that often accompanies aging and higher volumes of aerobic

197training.

199ACKNOWLEDGMENTS

200 None

201 17 Improving Bone Density | 9 18 202REFERENCES

203 1. Bassey, E. J., Rothwell, M.C., Littlewood, J.J., & Pye, D.W. (1998). Pre- and 204 postmenopausal women have different BMD responses to the same high-impact 205 exercise. J. Bone Miner. Res., 13, 1805– 1813. 206 207 2. Bilanin, J., Blanchard, M., & Russek-Cohen, E. (1989). Lower vertebral bone 208 density in male long distance runners. Med Sci Sports Exerc., 21, 66-70. 209 210 3. Cavanaugh, D. J., & Cann, C.E. (1988) Brisk walking does not stop bone loss in 211 postmenopausal women. Bone, 9, 201–204. 212 213 4. Chilibeck, P., Sale, D., & Webber, C. (1995). Exercise and bone mineral density. 214 Sports Medicine, 19, 103-122. 215 216 5. Cussler, E. C., Lohman, T.G. Going, S.B., Houtkooper, L. B., Metcalfe, L.L., 217 Flint-Wagner, H.G., Harris, R.B., & Teixeira, P.J. (2003). Weight lifted in 218 strength training predicts bone change in postmenopausal women. Med. Sci. 219 Sports Exerc., 35, 10 –17. 220 221 6. Dequeker, J., Nijs, J., Verstraeten, A., Geusens, P., & Gevers, G. (1987). Genetic 222 determinants of BMC at the spine and radius: a twin study. Bone, 8, 207–209. 223 224 7. Duncan, C. S., Blimkie, C., Cowell, C.T., Burke, S., Briody, J.N., & Howman- 225 Giles, R. (2002). Bone mineral density (BMD) in adolescent female athletes: 226 relationship to exercise type and muscle strength. Med. Sci. Sports Exerc., 34(2), 227 286–294, 2002. 228 229 8. Epstein, S. (1988). Serum and urinary markers of bone remodelling: assessment 230 of bone turnover. Endocrine Review, 9, 437-449. 231 232 9. Fisher, J.O., Mitchell, D.C., Smiciklas-Wright, H., Mannino, M.L.& Birch, L.L. 233 (2004). Meeting calcium recommendations during middle childhood reflects 234 mother-daughter beverage choices and predicts bone mineral status Am. J. Clin. 235 Nutr.,79, 698 –706. 236 237 10. Frost, H. (1987). Bone mass and the mechanostat: a proposal. Anat. Rec., 219, 1- 238 9. 239 240 11. Fuchs, R., Bauer, J., & Snow, C.(2001) Jumping improves hip and lumbar spine 241 bone mass in prepubescent children: A randomized controlled trial. J. Bone 242 Miner. Res., 16,148–156. 243 244 12. Gullberg, B., Johnell, O., & Kanis, J.A. (1997). World wide projections for hip 245 fracture. Osteoporosis. Int. 7, 407-413. 246 19 Improving Bone Density | 10 20 247 13. Helge, E. W., & kanstrup, I.L., (2002).. Bone density in female elite gymnasts: 248 impact of muscle strength and sex hormones. Med. Sci.Sports Exerc., 34(1), 174– 249 180. 250 251 14. Kanis, J. A., Melton, III, L.J., Christiansen, C., Johnsotn, C., & Khaltaev, N. 252 (1994). The diagnosis of osteoporosis. J. Bone Miner. Res., 9,1137–1141. 253 254 15. Kohrt, W., Bloomfield, S., Little, K., Nelson, M., & Yingling, V. (2004). ACSM 255 Position Stand: Physical Activity and Bone Health. Med. Sci. Sports Exerc. 256 1985-1996 257 258 16. Laynes, J., & Nelson, M.(2001) Resistance training for the prevention of 259 osteoporosis. In Resistance Training for Health and Rehabilitation. Graves, J., and 260 Franklin, B., eds. Human Kinetics, Champaign, Ill. pp 385-404. 261 262 17. Morris, F., Smith, R., Payne, W., Galloway, A., & Wark, J. (2000). Compressive 263 and shear force generated in the lumbar spine of female rowers. International 264 Journal of Sports Medicine, 21, 518-523. 265 266 18. Nelson, M. E., Fisher, E.C., Dilmanian, F.A., Dallal, G.E. & Evans, W.J. (1991). 267 A 1-y walking program and increased dietary calcium in postmenopausal women: 268 effects on bone. Am. J. Clin. Nutr. 53, 1304 –1311. 269 270 19. Ryan, A., Treuth, M., Rubin, M., Miller, J., Nicklas, B., Landis, D., Pratley, R., 271 Libanati, C., Gundberg, C., and Hurley, B. (1994). Effects of strength training on 272 bone mineral density: hormonal and bone turnover relationships. Journal of 273 Applied Physiology. 77: 1678-1684. 274 275 20. Sigurdsson, G. Halldorsson, B.V. Styrkarsdottir, U., Kristjansson, K., & 276 Stefansson, K (2008) Impact of Genetics on Low Bone Mass in Adults. Journal 277 of Bone and Mineral Research, 23,1584-1590 278 279 21. Stone, M. (1992). Connective tissue and bone responses to strength training. In 280 Strength and Power in Sport. P.V. Komi Editor. Blackwell Scientific Publications. 281 ,Cambridge, Mass. 282 283 22. Stewart, A. D., and Hannan, J. (2000). Total and regional bone density in male 284 runners, cyclists, and controls. Med. Sci. Sports Exerc., 32(8), 1373–1377. 285 286 23. Turner, C.H., & Robling, A.G. (2003) Designing exercise regimens to increase 287 bone strength. Exerc. Sport Sci. Rev., 31(1), 45–50. 288 289 24. Tylavsky, F.A., Holliday, K., Danish, R., Womack, C., Norwood, J.,& Carbone, 290 L. (2004). Fruit and vegetable intakes are an independent predictor of bone size in 291 early pubertal children. Am J Clin Nutr., 79, 311–7. 292 21 Improving Bone Density | 11 22 293 25. Zanker, C.L., & Cooke, C.B. (2004). Energy Balance, Bone Turnover, and 294 Skeletal Health in Physically Active Individuals. Med. Sci.Sports Exerc., 36(8), 295 1372–1381. 296