Improving Bone Density | 1
1
Article Type: Commentary
2
3
Article Category: Sports Fitness and Health
4
5
Title: Training to Improve Bone Density in Adults: A Review and Recommendations
6
7
Running Head: Improving Bone Density
8
9
Authors: Ed McNeely
10
11
Corresponding Author:
12
Ed McNeely, MS
13
One Academy Drive
14
Daphne Al, 36526
15
e.mcneely@xx.com
16
555-555-5555
17
18
Ed McNeely is the senior physiologist at the Peak Centre for Human Performance and a partner
19
in StrengthPro Inc. a Las Vegas based sport and fitness consulting company he is also a National
20
Faculty member of the United States Sports Academy
21
22
23
24
Improving Bone Density | 2
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
Training to Improve Bone Density in Adults: A Review and Recommendations
Improving Bone Density | 3
48
49
ABSTRACT
The loss of bone density is becoming a major health concern in industrialized
50
societies. Increasing bone density during puberty and young adulthood is considered the
51
best option for preventing the negative health consequences associated with osteoporosis,
52
even in middle aged and older adults an exercise program can increase bone density.
53
While low volume impact oriented aerobic activities like running have been shown to be
54
effective at increasing bone density excessive endurance training has been linked to low
55
bone density. Strength training remains the best option for adults wishing to increase
56
bone density. A regular program of high load (60-85% 1RM) training three or more times
57
per week using a variety of exercises that challenge all major muscles has been shown to
58
significantly increase bone density even in elderly adults.
59
60
61
62
63
64
65
66
67
68
69
70
71
72
Key words: bone density, exercise, osteoporosis, training
Improving Bone Density | 4
73
INTRODUCTION
74
Osteoporosis, which has been defined as bone mineral density (BMD) more than 2.5
75
standard deviations below the young adult mean value (14), is a growing health problem for both
76
men and women. In developed and developing countries the incidence of osteoporosis is
77
increasing at a rate faster than what would be predicted by the aging of the population alone (15).
78
In the U.S. It has been estimated that by 2025 the number of hip fractures attributed to
79
osteoporosis will double to nearly 2.6 million with a greater percentage increase in men than in
80
women (12).
81
Epidemiological evidence suggests that genetic factors are the most important cause of
82
osteoporosis (20) and can account for as much as 80% of the variability in bone density in the
83
population (6) but a variety of environmental factors have been linked to bone density including:
84
negative energy balance, low calcium intake, lack of fruit and vegetable consumption, low body
85
mass index, strength, and hormone levels (13,22,9,7,23), all of which may influence the ability to
86
develop or maintain bone density.
87
A well designed exercise can have a tremendous impact on bone, increasing density, size
88
and mechanical strength (23) and may be one of the keys to preventing complications associated
89
with osteoporosis. If bone density and maximum tensile strength are increased before
90
osteoporosis sets in, subsequent complications could be minimized (21). Unfortunately many
91
adults 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
93
is to maintain bone density. Without an exercise intervention, after the age of 40 bone mass
94
decreases by about 0.5% per year, regardless of sex or ethnicity (15). Whether appreciable
95
increases in bone density can occur for this age group is equivocal (15) and dependant on the
96
duration of the exercise program, age, dietary factors, and history of physical activity. A variety
97
of different types of exercise have been used in bone building programs middle aged or older
98
adults.
Improving Bone Density | 5
99
100
Training Techniques
Strength 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
103
to be effective for improving bone density in middle aged and older women who have low bone
104
density (16). Programs that have been successful at increasing bone density have several common
105
characteristics; training intensity above 70% 1RM, programs that last more than 12 months, and
106
training frequency greater than two times per week.
107
108
109
Endurance Training
Endurance training can be an acceptable form of exercise for maintaining or increasing
110
bone 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
112
athletes. They found that runners had greater total and leg BMD than controls, those athletes
113
participating in both cycling and running had greater total and arm BMD whereas the cyclists had
114
decreased spine BMD compared to controls. The lack of impact involved in cycling may explain
115
the lack of change in BMD even though all groups performed equal volumes of work throughout
116
the study period. Walking programs, because of their low impact, tend to show only modest or no
117
effects on BMD (3,18). Rowing because of the high compressive and shear forces placed on the
118
spine, 4.6 times body weight, has been shown to increase lumbar spine BMD but not at other
119
areas (17). Moderate training volumes seem to be more effective for increasing bone density.
120
Running mileage of 20-30 km per week has a positive effect on bone, particularly lower leg and
121
distal femur, but training volumes greater than this may cause a chronic increase in cortisol that
122
negatively impacts bone (4) and running 92 km per week has been shown to result in bone
123
density lower than sedentary controls (2).
124
Improving Bone Density | 6
125
126
Jump Training
Although effective and popular in school based programs for increasing bone density in
127
younger people jump training does not appear to be as effective in middle aged and older women.
128
In a study comparing the effects of 12 months of vertical jumping on spine and proximal femur
129
BMD 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
131
not in the post menopausal group compared to group specific controls. Interestingly, the lack of
132
change occurred even though the ground reaction forces and rate of force development on landing
133
were higher in the post menopausal group resulting in a greater strain overload than in the pre
134
menopausal group.
135
While a variety of exercise modalities have proven to be effective at maintaining bone
136
density in adults there some basic principals should be considered when designing a long term
137
program for people with osteoporosis:
138
139
Exercise Considerations
140
Use a progressive program
141
Increase resistance and intensity progressively. This is necessary because for bone to
142
form it requires a minimum amount of strain. Once a bone adapts to a given strain level, the
143
stimulus for bone to form is removed and a higher strain level becomes necessary for it to adapt
144
further (10).
145
146
147
Use dynamic movements
Mechanical loading of bone has an osteogenic effect only if the loading is dynamic and
148
variable, static loading of bone does not trigger an adaptive response (23). Impact and rapid
149
changes of direction can be particularly effective because ground reaction forces tend to be
150
highest during these activities. Jumps, running, and more explosive or dynamic strength training
Improving Bone Density | 7
151
activities should make up the majority of exercise in a bone building program. In adults with
152
advanced osteoporosis more explosive exercises should be phased in gradually as their
153
conditioning and bone strength improves.
154
155
Vary the exercises
156
Bone adaptations occur primarily at insertion and origin points where muscles attach to
157
the bones. Ryan et al. (1994) suggest that increased BMD from strength training and explosive
158
activities is related to the load placed on the muscles that act as prime movers. A wide variety of
159
exercises, which change every 2-4 weeks, exercising the whole body will help ensure that all
160
bones receive stimulus to increase BMC or BMD.
161
162
Minimum intensity
163
As with most training there is a minimum level of intensity that is needed to stimulate
164
increase in BMD. For strength training activities there is a linear relationship between weight
165
lifted and improvements in bone density (5) Chilibeck, Sale and Webber (1995) suggest that for
166
strength training intensities of at least 60% 1RM are needed to increase BMD, with faster and
167
greater increases in bone density coming as intensity climbs (16). For impact activities like
168
running and jumping ground reaction forces of greater than two times body weight can increase
169
bone density with higher forces having a greater effect.
170
171
Training frequency
172
Improvements in BMD can occur with relatively short training sessions if high impact
173
activities like jumping are the core of the program. However, there is a need to perform these
174
sessions frequently. Studies of jump training have found that where three or more sessions per
175
week is sufficient to increase bone two session per week has negligible effect on bone density
176
(11).
Improving Bone Density | 8
177
178
179
Program duration
Consistency is one of the keys to long term bone health. Like other tissues bone
180
undergoes both adaptation to training and detraining during periods of decreased activity. The
181
bone remodelling cycle lasts four to six months (8); this is the minimum period of time needed
182
for BMD to change significantly. Training programs need to be designed so that they offer the
183
variety and adaptability for people to make them a year round part of lifelong fitness regime.
184
185
CONCLUSIONS
186
Decreased bone density is a growing problem in modern societies. Exercise remains one
187
of the most potent alternatives to drug treatments for maintaining or improving bone density. An
188
intensive program, three or more times per week featuring a variety of exercises, that considers
189
the individual needs of each person and promotes long term compliance, can have a positive
190
impact on bone density.
191
192
APPLICATIONS IN SPORT
193
Over the past years adults have become more and more active in age group sports,
194
particularly in the endurance sports like running, cycling and triathlon. The inclusion of an
195
intensive strength training program will not only improve their performance but help offset the
196
decrease in bone density that often accompanies aging and higher volumes of aerobic
197
training.
198
199
200
201
ACKNOWLEDGMENTS
None
Improving Bone Density | 9
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
REFERENCES
1. Bassey, E. J., Rothwell, M.C., Littlewood, J.J., & Pye, D.W. (1998). Pre- and
postmenopausal women have different BMD responses to the same high-impact
exercise. J. Bone Miner. Res., 13, 1805– 1813.
2. Bilanin, J., Blanchard, M., & Russek-Cohen, E. (1989). Lower vertebral bone
density in male long distance runners. Med Sci Sports Exerc., 21, 66-70.
3. Cavanaugh, D. J., & Cann, C.E. (1988) Brisk walking does not stop bone loss in
postmenopausal women. Bone, 9, 201–204.
4. Chilibeck, P., Sale, D., & Webber, C. (1995). Exercise and bone mineral density.
Sports Medicine, 19, 103-122.
5. Cussler, E. C., Lohman, T.G. Going, S.B., Houtkooper, L. B., Metcalfe, L.L.,
Flint-Wagner, H.G., Harris, R.B., & Teixeira, P.J. (2003). Weight lifted in
strength training predicts bone change in postmenopausal women. Med. Sci.
Sports Exerc., 35, 10 –17.
6. Dequeker, J., Nijs, J., Verstraeten, A., Geusens, P., & Gevers, G. (1987). Genetic
determinants of BMC at the spine and radius: a twin study. Bone, 8, 207–209.
7. Duncan, C. S., Blimkie, C., Cowell, C.T., Burke, S., Briody, J.N., & HowmanGiles, R. (2002). Bone mineral density (BMD) in adolescent female athletes:
relationship to exercise type and muscle strength. Med. Sci. Sports Exerc., 34(2),
286–294, 2002.
8. Epstein, S. (1988). Serum and urinary markers of bone remodelling: assessment
of bone turnover. Endocrine Review, 9, 437-449.
9. Fisher, J.O., Mitchell, D.C., Smiciklas-Wright, H., Mannino, M.L.& Birch, L.L.
(2004). Meeting calcium recommendations during middle childhood reflects
mother-daughter beverage choices and predicts bone mineral status Am. J. Clin.
Nutr.,79, 698 –706.
10. Frost, H. (1987). Bone mass and the mechanostat: a proposal. Anat. Rec., 219, 19.
11. Fuchs, R., Bauer, J., & Snow, C.(2001) Jumping improves hip and lumbar spine
bone mass in prepubescent children: A randomized controlled trial. J. Bone
Miner. Res., 16,148–156.
12. Gullberg, B., Johnell, O., & Kanis, J.A. (1997). World wide projections for hip
fracture. Osteoporosis. Int. 7, 407-413.
Improving Bone Density | 10
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
13. Helge, E. W., & kanstrup, I.L., (2002).. Bone density in female elite gymnasts:
impact of muscle strength and sex hormones. Med. Sci.Sports Exerc., 34(1), 174–
180.
14. Kanis, J. A., Melton, III, L.J., Christiansen, C., Johnsotn, C., & Khaltaev,
N.(1994). The diagnosis of osteoporosis. J. Bone Miner. Res., 9,1137–1141.
15. Kohrt, W., Bloomfield, S., Little, K., Nelson, M., & Yingling, V. (2004). ACSM
Position Stand: Physical Activity and Bone Health. Med. Sci. Sports Exerc.
1985-1996
16. Laynes, J., & Nelson, M.(2001) Resistance training for the prevention of
osteoporosis. In Resistance Training for Health and Rehabilitation. Graves, J., and
Franklin, B., eds. Human Kinetics, Champaign, Ill. pp 385-404.
17. Morris, F., Smith, R., Payne, W., Galloway, A., & Wark, J. (2000). Compressive
and shear force generated in the lumbar spine of female rowers. International
Journal of Sports Medicine, 21, 518-523.
18. Nelson, M. E., Fisher, E.C., Dilmanian, F.A., Dallal, G.E. & Evans, W.J. (1991).
A 1-y walking program and increased dietary calcium in postmenopausal women:
effects on bone. Am. J. Clin. Nutr. 53, 1304 –1311.
19. Ryan, A., Treuth, M., Rubin, M., Miller, J., Nicklas, B., Landis, D., Pratley, R.,
Libanati, C., Gundberg, C., and Hurley, B. (1994). Effects of strength training on
bone mineral density: hormonal and bone turnover relationships. Journal of
Applied Physiology. 77: 1678-1684.
20. Sigurdsson, G. Halldorsson, B.V. Styrkarsdottir, U., Kristjansson, K., &
Stefansson, K (2008) Impact of Genetics on Low Bone Mass in Adults. Journal
of Bone and Mineral Research, 23,1584-1590
21. Stone, M. (1992). Connective tissue and bone responses to strength training. In
Strength and Power in Sport. P.V. Komi Editor. Blackwell Scientific Publications.
,Cambridge, Mass.
22. Stewart, A. D., and Hannan, J. (2000). Total and regional bone density in male
runners, cyclists, and controls. Med. Sci. Sports Exerc., 32(8), 1373–1377.
23. Turner, C.H., & Robling, A.G. (2003) Designing exercise regimens to increase
bone strength. Exerc. Sport Sci. Rev., 31(1), 45–50.
24. Tylavsky, F.A., Holliday, K., Danish, R., Womack, C., Norwood, J.,& Carbone,
L. (2004). Fruit and vegetable intakes are an independent predictor of bone size in
early pubertal children. Am J Clin Nutr., 79, 311–7.
Improving Bone Density | 11
293
294
295
296
25. Zanker, C.L., & Cooke, C.B. (2004). Energy Balance, Bone Turnover, and
Skeletal Health in Physically Active Individuals. Med. Sci.Sports Exerc., 36(8),
1372–1381.