Full text of DOI:10.1359/jbmr.2001.16.1.175

JOURNAL OF BONE AND MINERAL RESEARCH
Volume 16, Number 1, 2001
© 2001 American Society for Bone and Mineral Research
Resistance Training over 2 Years Increases Bone Mass in
Calcium-Replete Postmenopausal Women
DEBORAH KERR,1 TIMOTHY ACKLAND,2 BARBARA MASLEN,2 ALAN MORTON,2
and RICHARD PRINCE3
ABSTRACT
Understanding the stress/strain relationship between exercise and bone is critical to understanding the
potential benefit of exercise in preventing postmenopausal bone loss. This study examined the effect of a 2-year
exercise intervention and calcium supplementation (600 mg) on bone mineral density (BMD) in 126 post-
menopausal women (mean age, 60 ؎ 5 years). Assignment was by block randomization to one of three groups:
strength (S), fitness (F), or nonexercise control (C). The two exercise groups completed three sets of the same
nine exercises, three times a week. The S group increased the loading, while the F group had additional
stationary bicycle riding with minimal increase in loading. Retention at 2 years was 71% (59% in the S group,
69% in the F group, and 83% in the C group), while the exercise compliance did not differ between the
exercise groups (S group, 74 ؎ 13%; F group, 77 ؎ 14%). BMD was measured at the hip, lumbar spine, and
forearm sites every 6 months using a Hologic 4500. Whole body BMD also was measured every 6 months on
a Hologic 2000. There was no difference between the groups at the forearm, lumbar spine, or whole body sites.
There was a significant effect of the strength program at the total (0.9 ؎ 2.6%; p < 0.05) and intertrochanter
hip site (1.1 ؎ 3.0%; p < 0.01). There was a significant time and group interaction (p < 0.05) at the
intertrochanter site by repeated measures. This study shows the effectiveness of a progressive strength
program in increasing bone density at the clinically important hip site. We concluded that a strength program
could be recommended as an adjunct lifestyle approach to osteoporosis treatment or used in combination with
other therapies. (J Bone Miner Res 2001;16:175–181)
Key words: osteoporosis, exercise, strength training, resistance training
bone mass.(1–8) However, evidence from animal and human
INTRODUCTION
studies suggests that strength training may have more fa-
NDERSTANDING THE adaptation of bone to exercise is vorable effects on maintaining or increasing bone mass.
U
critically important in designing public health strategies Bone is sensitive primarily to the short periods of load-
ing(9,10) with unusual strain distributions, high peak strain
magnitudes, and rapid change of strain. The results of
animal studies suggest that greater strain magnitudes and
unusual strain distributions provide the most effective stim-
ulus for bone formation.(11,12) These findings have led to a
number of studies that showed a positive effect of strength
for the prevention of osteoporosis. Previous exercise studies
have shown a positive effect of weight-bearing exercise on
*Presented in part at the 2nd Joint Meeting of the American
Society for Bone and Mineral Research-International Bone and
Mineral Society, San Francisco, California, USA, December 1998.
1School of Public Health, Curtin University of Technology, Perth, Western Australia.
2Department of Human Movement and Exercise Science, The University of Western Australia, Perth, Western Australia.
3Department of Medicine, The University of Western Australia, Perth, Western Australia.
175

176
KERR ET AL.
training on bone mass in both premenopausal(13–17) and neck or femur site was defined as a rectangle 6.0 mm wide
postmenopausal women.(18–19)
traversing the femoral neck placed against the greater tro-
In a previous unilateral exercise study, we compared two chanter. The trochanter site was a triangular region with
strength training regimens that differed only in the number boundaries defined as the lateral edge of the femoral neck
of repetitions of the weight lifted. The strength program area to a point where the edge of the femur changes curva-
significantly increased bone density at the hip and forearm ture below the trochanter. The intertrochanteric region was
sites whereas the endurance program did not.(19) The effects the remainder of the femur extending 10.0 mm below the
of strength training were specific to the site of loading and lesser trochanter, and Ward’s triangle site was a machine-
load dependent. Because the study was for 1 year, it was not determined site in the center of the femoral neck.
clear if the positive effects on bone mass could be main-
The radial forearm BMD site was defined as the area of
tained over a longer time. Therefore, we have designed a the radius at the ultradistal site (UD), the midsite, and the
2-year, randomized, controlled trial to compare the same one-third site as follows: UD site was defined as the area
strength training regimen but with different degrees of load- from 2 pixels proximal to the base of the articular surface,
ing. The purpose was to investigate the effects of two at the base of the ulnar-styloid process to 10.0 cm proxi-
exercise interventions compared with a nonexercise control mally; midsite was defined as the area extending from the
on postmenopausal bone loss. The strength group aimed at proximal edge of the UD area to the distal edge of the
promoting muscular strength gains while the fitness group one-third site; and the one-third site was defined as the area
aimed at improving cardiovascular fitness. We hypothesized extending from the edge of the midsite. The forearm was in
that the strength protocol would reduce the rate of bone loss a horizontal position with the elbow resting on the table and
in postmenopausal women whereas the fitness protocol the hand held loosely cupped over the plastic apparatus
would not.
provided by Hologic. The left forearm was scanned in all
subjects except those who were left-hand dominant where
the right was used. The lumbar spine BMD was measured
according to a standard protocol, with the scanned region
from the fourth to the first lumbar vertebrae. The subject’s
MATERIALS AND METHODS
Recruitment of subjects was from volunteers who re- legs were placed on the cushion provided to flatten the
sponded to media articles. Telephone screening was com- lumbar spine. A whole body scan using the array mode was
pleted initially and 163 subjects who were eligible for the measured every 6 months using a QDR 2000 machine.
study attended an information seminar. After signing an Subjects were scanned while lying supine on the table with
informed consent, 141 women agreed to undergo bone arms at the side. The Step Phantom (tissue bar) was placed
density testing and a final 126 women were randomized into beside the subject’s feet on the right side and is used to
the study. The subjects consisted of 126 women who were calibrate lean and fat-equivalent tissue. The scans were
more than 4 years past menopause and physically capable of analyzed using standard software program supplied by the
entering exercise groups but who were not already exercis- manufacturer for bone mineral content (BMC), BMD, and
ing at a moderate intensity more than 2 h/week. Women soft tissue body composition. The CVs in our laboratory
who had performed resistance weight training in the previ- were 1% at the lumbar spine and whole body, 1.6% for the
ous 5 years were excluded. Other exclusion criteria included radius UD site, 1.4% for the radius midsite, and 1.3% for the
those on hormone replacement or other medications or who radius one-third site. At the hip site, the CV was 1.5% at the
had diseases known to affect bone density and those who femoral neck, 1.3% at the trochanter, 1.3% at the intertro-
had cardiovascular, physical, or orthopedic disabilities that chanter, and 3.3% at Ward’s triangle.
would place the subjects at risk or limit their ability to
Each subject completed an activity record for a 7-day
perform exercise. The study was approved by the Human period on three occasions—at baseline, 1 year, and 2 years.
Rights Committee of The University of Western Australia. From these records, the subject’s most active 2 h of the day
Bone density was measured using the array mode at the was scored using tables of metabolic equivalent activities(20)
hip, lumbar spine, and radial forearm at 6-month intervals as a measure of the aerobic activity to derive an activity
from baseline using dual-energy X-ray technology, on a score (MET). One metabolic equivalent was defined as the
QDR 4500 machine and for the whole body on a QDR 2000 energy consumed per minute sitting at rest and other activ-
machine (Hologic Inc., Waltham, MA, USA). Throughout ities were measured in relation to that standard. The values
the study, daily calibration checks were performed on both for an average 55-kg woman were used.
machines using spine phantoms provided by the manufac-
turer. Recalibration also was performed during each main-
Study design
tenance event. As an extra quality assurance measure, roll-
Assignment was by block randomization to one of three
ing averages of phantom-derived data were computed for groups: a strength group (S), fitness group (F), or nonexer-
each machine over the entire period of the study. From these cise control group (C). The S group protocol was designed
data, look-up tables were devised to permit small correc- to emphasize skeletal loading whereas the F group empha-
tions for long-term machine drifts, based on the machine sized aerobic fitness. All subjects were given 600 mg of
and the date of the scan. The hip bone mineral density elemental calcium per day. Compliance with calcium sup-
(BMD) site was measured using the array mode and in- plementation and the exercise intervention was recorded.
cluded the area of the femoral neck, trochanter, and inter- Data collection was completed at baseline and every 6
trochanter site. The left hip was scanned in all subjects. The months thereafter.

EXERCISE IN OSTEOPOROSIS TREATMENT
177
FIG. 1. The percentage change (ϮSEM) from baseline over the 2 years of the study. (A) The intertrochanter hip site, the
S group was significantly different (p Ͻ 0.01) from the F and C groups; (B) the total hip site, the S group was significantly
different (p Ͻ 0.05) from the F and C groups; (C) the lumbar spine; and (D) whole body, no significant difference between
the groups. All p values were calculated from repeated measures (Œ, S group; f, F group; F, C group).
The two exercise groups attended three, 1-h sessions per and interaction effects for bone density were examined
week at the Human Movement and Exercise Science Weight using a two-way analysis of variance (ANOVA) with re-
Training Laboratory. Both exercise groups completed a peated measures on one factor (time). All p values were
warm-up consisting of brisk walking and stretching. This was calculated from repeated measures ANOVA. However, the
followed by 30 minutes of resistance weight training exercises. bone density data, as shown in Fig. 1, are presented as the
Both groups completed the same nine exercises but the S group percentage change from baseline for clarity. A linear regres-
completed three sets of eight repetitions (3 ϫ 8 RM). The S sion function was calculated by least squares regression for
group progressively increased their load throughout the study, each individual completing the study and was used to derive
at an individually tailored increment. The F group exercised for a measure of the rate of change. Group comparisons were
40-s at each station with a 10-s break between and there was made by one-way ANOVA followed by Tuckey’s post hoc
only minimal increase in load for the duration of the study. The test. Statistical analysis was conducted using Spearman’s
F group also performed additional stationary bicycle riding for rank correlation and stepwise multiple regression analysis.
40-s stations at a moderate intensity (heart rate less than 150 The dependent variable was the outcome variable and the
beats/minute). Although the F group performed the same re- independent variable was the predictor variable. The results
sistance exercises as the S group, these were done using a were analyzed also after adjustment for years since meno-
minimal load and this load was not altered over the course of pause and adjustment for weight. Residuals were examined
the study. The following exercises were selected so as to cause for normality and all significance tests were two-tailed.
compression or tensile loading at the scanned sites: wrist curl,
reverse curl, biceps curl, triceps pushdown, hip flexion, hip
extension, latissimus dorsi pull down, and calf raise. Qualified
exercise physiologists supervised all exercise sessions.
RESULTS
There were no differences in the baseline characteristics
of subjects, with the exception of age in the C group, who
were significantly older than the S or F group (Table 1).
Statistical treatment
Statistical analysis was conducted using SPSS version 8.0 There was a difference in the years since menopause be-
for Windows (SPSS, Inc., Chicago, IL USA). Time, group, tween groups, but this was not significant. The baseline

178
KERR ET AL.
TABLE 1. BASELINE CHARACTERISTICS FOR S, F, AND C GROUPS
Characteristic
S group
F group
C group
No. of subjects
42
42
42
Age (years)
60 Ϯ 5
59 Ϯ 5
62 Ϯ 6*
Years since menopause
Body mass (kg)
Stature (cm)
11 Ϯ 6
9 Ϯ 5
12 Ϯ 6
72.2 Ϯ 12.0
163.3 Ϯ 5.4
32.0 Ϯ 9.2
43 Ϯ 6
39.5 Ϯ 4.2
402 Ϯ 50
69.0 Ϯ 11.4
165.3 Ϯ 5.8
28.8 Ϯ 9.4
40 Ϯ 7
39.6 Ϯ 4.3
390 Ϯ 53
69.3 Ϯ 14.6
162.4 Ϯ 6.6
29.5 Ϯ 10.9
41 Ϯ 8
39.0 Ϯ 4.9
388 Ϯ 59
Body fat (kg)
Percentage body fata (%)
Lean body mass (kg)
Activity (METS)
Total spine BMD (g/cm2)
Total hip BMD (g/cm2)
Trochanter BMD (g/cm2)
Intertrochanter BMD (g/cm2)
Neck of femur BMD (g/cm2)
Radius UD BMD (g/cm2)
Radius midultradistal BMD (g/cm2)
Radius one-third (g/cm2)
0.90 Ϯ 0.16
0.86 Ϯ 0.12
0.67 Ϯ 0.10
1.01 Ϯ 0.15
0.72 Ϯ 0.11
0.36 Ϯ 0.07
0.53 Ϯ 0.06
0.62 Ϯ 0.08
0.91 Ϯ 0.12
0.84 Ϯ 0.11
0.65 Ϯ 0.09
1.00 Ϯ 0.15
0.72 Ϯ 0.09
0.36 Ϯ 0.07
0.53 Ϯ 0.07
0.62 Ϯ 0.06
0.94 Ϯ 0.16
0.89 Ϯ 0.15
0.70 Ϯ 0.10
1.05 Ϯ 0.15
0.76 Ϯ 0.11
0.36 Ϯ 0.06
0.53 Ϯ 0.07
0.61 Ϯ 0.08
a Calculated from dual-energy x-ray absorptiometry. Results are mean Ϯ SD.
* p Ͻ 0.05, the C group is significantly different from the S and F groups.
BMD for all sites is shown in Table 1. There was no the study, the compliance was 61 Ϯ 23% for the S group
difference between the groups at baseline. In addition, there and 67 Ϯ 20% for the F group. The average exercise
was no difference in body weight between the groups at compliance over 2 years was 74 Ϯ 13% in the S group and
baseline or at any time point throughout the study.
77 Ϯ 14% in the F group.
The overall retention of subjects in the study was 71% at
Percentage changes in BMD for each group are shown in
2 years. The lowest retention at 2 years was in the S group Table 2. There was a significant time and group effect of the
(59%), compared with 69% in the F group and 83% in the strength program on change in BMD at the intertrochanter
control group. Most of the subjects withdrew from the S (1.1 Ϯ 3.0%; p Ͻ 0.01) and the total hip site (0.9 Ϯ 2.6%;
group in the first 6 months of the study (69%) compared p Ͻ 0.05; Table 2, Fig. 1) as determined by repeated
with a 93% retention in the F group and 86% in the control measures ANOVA. The addition of years since menopause
group. The most common reason for withdrawal was “time” and body weight as covariants did not change the result of
with 13 women withdrawing for this reason. Three other the repeated measures ANOVA. The maximum gain in
women elected to commence hormone replacement therapy BMD in the S group occurred in the first 6 months (1.6 Ϯ
and were withdrawn from the study. Two subjects had a 3.0%) and was maintained for the remainder of the study
preexisting back and shoulder injury and another subject (0.2 Ϯ 3.2% from 6 to 12 months; Ϫ0.5 Ϯ 2.7% from 12 to
developed an injury to the wrist. These 3 subjects were in 18 months; 0.2 Ϯ 3.0% from 18 months to 2 years). The F
the F group and were unable to continue with the exercise and C groups lost bone at the intertrochanter hip site such
program. Four subjects moved interstate and another 4 that the difference between the S group and other two
withdrew for family reasons. There was no difference at groups was 3.2% greater at 2 years. There was no difference
baseline between those subjects who withdrew from the between the groups at the neck of femur or intertrochanter
study compared with those who finished the study for BMD sites at any time point. There was no significant group
weight, height, activity score, or hip BMD. Women who effect at the forearm or lumbar spine sites (Table 2). There
withdrew from the study did not attend the final measure- also was no change in the BMC or area at the forearm, total
ment occasion; therefore, we were unable to analyze the hip, or neck of femur sites in either group throughout the
data for an “intention-to-treat” analysis.
study. The whole body BMD decreased in all three groups
Exercise compliance was evaluated by a record of atten- over the 2 years.
dance kept by the exercise physiologist supervising the
Linear regression analysis was performed for the S group
session. Compliance was defined as percentage of atten- using rate of change of BMD at the intertrochanter and total
dance of all available training sessions. All subjects who hip sites as the dependent variable. The only significant
finished the study were included in the analysis, regardless predictor of BMD at the intertrochanter and total hip sites
of their exercise compliance. There was no significant dif- was the baseline activity score (r ϭ Ϫ0.50 and p Ͻ 0.05;
ference between the groups at any time throughout the r ϭ Ϫ0.46 and p Ͻ 0.05, respectively), which was corre-
study. Exercise compliance was very high in the first 6 lated negatively. Exercise compliance was not a significant
months for both groups (S group, 90 Ϯ 12%; F group, 92 Ϯ predictor of the rate of change nor was years since meno-
8%) but declined from this point on. In the last 6 months of pause or body weight. There was no relationship in the S

EXERCISE IN OSTEOPOROSIS TREATMENT
179
TABLE 2. THE CHANGE IN BMD FOR THE HIP, LUMBAR SPINE, FOREARM, AND WHOLE BODY SITES EXPRESSED AS PERCENT
CHANGE PER YEAR FOR THE S (n ϭ 24), F (n ϭ 30), AND C (n ϭ 36) GROUPS FOR
SUBJECTS COMPLETING THE STUDY
Site
S group
F group
C group
Intertrochanter
Neck of femur
Trochanter
Total hip
Lumbar spine
Radius UD
Radius mid-UD
Radius one-third
Whole body
0.70 Ϯ 2.08*
1.04 Ϯ 2.81
0.00 Ϯ 2.33
Ϫ1.07 Ϯ 2.49
0.03 Ϯ 2.22
Ϫ1.18 Ϯ 2.57
Ϫ0.11 Ϯ 2.60
Ϫ0.01 Ϯ 2.74
Ϫ0.57 Ϯ 1.97
Ϫ0.01 Ϯ 1.98
Ϫ0.55 Ϯ 3.03
Ϫ0.47 Ϯ 2.24
0.05 Ϯ 2.42
Ϫ0.02 Ϯ 2.60
Ϫ0.65 Ϯ 1.81
Ϫ0.32 Ϯ 1.85
Ϫ0.39 Ϯ 3.19
Ϫ1.21 Ϯ 1.84
Ϫ0.96 Ϯ 2.50
Ϫ0.79 Ϯ 1.73
0.57 Ϯ 1.76†
Ϫ0.65 Ϯ 2.12
Ϫ0.71 Ϯ 2.77
Ϫ0.35 Ϯ 2.25
Ϫ0.07 Ϯ 2.65
Ϫ0.62 Ϯ 1.38
Ϫ0.71 Ϯ 1.69
* p Ͻ 0.01 and †p Ͻ 0.05 for S group compared with F and exercise C groups (post hoc analysis positive for Duncans and Tukeys).
group, between baseline BMD or exercise compliance and
the rate of change of BMD, as assessed by the regression
slope. Multiple regression was performed with rate of
change in body density of the intertrochanter site for the S
group as the dependent variable and total METS, years since
menopause, muscle strength, exercise compliance, and
baseline submaximal fitness as the independent variables.
The results showed that baseline activity (METS) was a
significant negative correlate of rate of change in bone
density for the S group [r ϭ Ϫ0.50, r2 ϭ 0.25, and slope ϭ
Ϫ(2.0 ϫ 10Ϫ5)total METS ϩ 8.5 ϫ 10Ϫ2].
Our results suggest that in the S group, those women who
were least active at the start of the study were the most
likely to respond to the intervention. The adaptation to
mechanical loading is driven by the strain threshold de-
tected in bone.(12) Low activity in the elderly may be per-
ceived as disuse and contribute to the bone loss, alterna-
tively high activity, or strain thresholds, which are
perceived as abnormal may stimulate osteogenesis. How-
ever, because the baseline activity only partially accounted
for the rate of change in bone density, there are other
predictor variables of the rate of change in bone density for
the S group that we have been unable to identify.
The results of this study are consistent with our previous
findings. In a 1-year strength training study, using a similar
exercise protocol, there was a significant increase in the
BMD at the trochanter, intertrochanter, and forearm
sites.(19) This study was able to show that a strength training
program was site specific and load dependent. In the current
study, no effect on BMD was observed at the forearm site.
The reason for this is not clear but may be caused by
differences in the exercise protocol used in the current
study. The previous study included a forearm pronation and
supination exercise but this was excluded from the current
study. This exercise causes torsional loading at the forearm
and may be a powerful stimulus for osteogenesis. Of the
exercises designed to stress the hip region, hip flexion, hip
extension, and leg press were included. The main difference
from the previous study was the exclusion of hip abduction
and adduction, which may have decreased the amount and
direction of loading at the hip site and could account for the
lack of effect observed at the trochanter hip site. No rela-
tionship was seen between the change in muscle strength
and rate of change of bone density at the hip. This was in
contrast to our previous findings in which we did show a
relationship between the change in strength and bone den-
sity at several hip sites. This may be explained by the
differences in the exercise protocol between the current and
the previous study.
DISCUSSION
This study has shown a significant effect of strength
training in postmenopausal women over 2 years at the
clinically important intertrochanter hip site. Furthermore,
we have shown the feasibility of this type of exercise for the
prevention of osteoporosis or as an adjunct to other treat-
ments. However, there was no added benefit on bone den-
sity of a circuit program, which aimed to improve aerobic
fitness, over calcium supplementation alone. This suggests
the load applied to the skeleton from strength training is the
critical factor for the increased bone density observed.
The maximum change in bone density for the S group
occurred in the first year of the intervention. There was a
relative decline in the rate of change during the second year
but the bone density remained more than a 3% difference
between the S, F, and C groups after 2 years. This is
consistent with Frost’s theory in which he proposed a min-
imum effective strain (MESm) for bone modeling and re-
modeling and only when the bone strain exceeds the MESm
will a net gain in bone occur.(21) Although subjects were
encouraged to increase progressively the loading throughout
the study, over time the strains may have fallen below the
level required to increase the bone density. We did not find
a relationship between compliance and rate of change of
BMD. However, compliance was measured by attendance at
the sessions but there is no way to be able to measure the
intensity of effort.
The lack of effect observed at the spine suggests that
insufficient loading occurred with the strength training in-
tervention. In younger premenopausal women, strength

180
KERR ET AL.
training has shown a positive effect at the lumbar spine in
several studies.(14,17) Snow-Harter et al.(14) found a signifi-
cant increase of 1.2% at the lumbar spine but no change at
the femur with an 8-month strength training program. In an
18-month strength training program in premenopausal
women, Lohman et al.(17) showed a significant effect with
the exercise intervention at the lumbar spine and femur
trochanter. Two studies conducted on postmenopausal
women did show an effect at the lumbar spine.(18,22) The
study by Pruitt et al.(22) was conducted over 9 months but
was not randomized and had only 17 subjects. A significant
effect was observed at the lumbar spine but not at the hip or
forearm sites. Nelson et al.,(18) in a randomized controlled
trial of 1 year of strength training in postmenopausal
women, found a significant effect at the femoral neck and
lumbar spine. The exercise protocol was similar to the
current study except that only two sessions per week were
performed and included trunk extension and abdominal
flexion exercises, which may have increased the loading on
the lumbar spine.
In conclusion, a progressive strength training program,
designed to promote maximum strength gains, is effective at
increasing bone density over 2 years at the clinically im-
portant intertrochanter site. The fitness regimen did not
increase bone mass but may be more feasible as the reten-
tion was greater in this group. Strength training can be
recommended as an adjunct lifestyle approach to osteopo-
rosis prevention or in combination with other treatments in
postmenopausal women.
ACKNOWLEDGMENTS
This study was supported by Healthway—the Western
Australian Health Promotion Foundation, The Arnold
Yeldham and Mary Raine Medical Research Foundation,
and Whitehall Laboratories.
REFERENCES
A positive effect of the calcium supplementation on bone
density for all three groups cannot be excluded. The study
by Prince et al.,(8) which examined the effect of calcium
supplementation on postmenopausal women, showed the
placebo group lost bone at the trochanter, intertrochanter,
and neck of femur sites whereas the calcium supplemented
groups did not. In the current study, all three groups re-
ceived a calcium supplement of 600 mg/day. We did not
observe a loss of bone at the trochanter or neck of femur
sites in any of the three groups. This suggests that the
calcium supplement may have slowed the rate of bone loss
in all three groups.
The lack of effect of the fitness program on the BMD
suggests that the exercise load was not sufficient to cause
skeletal adaptation. Although the subjects performed the
same exercises as the S group, they did more repetitions and
had only a minimal increase in load throughout the study.
The F group did additional stationary cycling but this was a
weight-supported activity and was aimed at improving car-
diovascular fitness. It would appear that the loads achieved
were no more than those achieved with activities of daily
living. However, the retention was greater in the F group,
which suggests this program was more feasible for the
volunteers. This has implications for exercise programming
in postmenopausal women. Novices to strength training
should be commenced on a fitness circuit program to famil-
iarize them with strength training, gradually increasing the
weight lifted and decreasing the number of repetitions. This
is particularly important for older participants who may take
longer to adapt to exercise training.(23)
1. Heinonen A, Kannus P, Sievanen H, Oja P, Pasanen M, Rinne
M, Uusi-Rasi K, Vuori I 1996 Randomised controlled trial of
effect of high-impact exercise on selected risk factors for
osteoporotic fractures. Lancet 348:1343–1347.
2. Heinonen A, Oja P, Sievanen H, Vuori I 1998 Effect of two
training regimens on bone mineral density in healthy perim-
enopausal women: A randomized controlled trial. J Bone
Miner Res 13:483–490.
3. Dalsky GP, Stocke KS, Ehsani AA, Slatopolsky E, Lee WC,
Birge SJ 1988 Weight-bearing exercise training and lumbar
bone mineral content in postmenopausal women. Ann Intern
Med 108:824–828.
4. Simkin A, Ayalon J, Leichter I 1987 Increased trabecular bone
density due to bone-loading exercises in postmenopausal os-
teoporotic women. Calcif Tissue Int 40:59–63.
5. Smith EL, Gilligan C, McAdam M, Ensign CP, Smith PE
1989 Deterring bone loss by exercise intervention in pre-
menopausal and postmenopausal women. Calcif Tissue Int
44:312–321.
6. Chow R, Harrison JE, Notarius C 1987 Effect of two random-
ised exercise programs on bone mass of healthy postmeno-
pausal women. BMJ 295:1441–1444.
7. Grove KA, Londeree BR 1992 Bone density in postmeno-
pausal women: High impact vs low impact exercise. Med Sci
Sports Exerc 24:1190–1194.
8. Prince R, Devine A, Dick I, Criddle A, Kerr D, Kent N, Price
R, Randell A 1995 The effects of calcium supplementation
(milk powder or tablets) and exercise on bone density in
postmenopausal women. J Bone Miner Res 10:1068–1075.
9. Chambers TJ, Evans M, Gardner TN, Turner-Smith A, Chow
JWM 1993 Induction of bone formation in rat tail vertebrae by
mechanical loading. Bone Miner 20:167–178.
10. Chow JWM, Jagger CJ, Chambers TJ 1993 Characterization
of osteogenic response to mechanical stimulation in cancel-
lous bone of rat caudal vertebrae. Am J Physiol 265:E340–
E347.
11. Lanyon LE, Rubin CT 1984 Static vs dynamic loads as an
influence on bone remodelling. J Biomech 17:897–905.
12. Rubin CT, Lanyon LE 1985 Regulation of bone mass by
mechanical strain magnitude. Calcif Tissue Int 37:411–417.
13. Gleeson PB, Protas EJ, LeBlanc AD, Schneider VS, Evans HJ
1990 Effects of weight lifting on bone mineral density in
premenopausal women. J Bone Miner Res 5:153–158.
14. Snow-Harter C, Bouxsein ML, Lewis BT, Carter DR, Marcus
R 1992 Effects of resistance and endurance exercise on bone
We have shown that a strength program is effective in
increasing bone density at the intertrochanter hip site. How-
ever, strength training does not improve cardiovascular fit-
ness. Walking programs have been shown to be effective in
slowing bone loss(8,24) and improving cardiovascular fitness
if they are of sufficient duration and intensity. Strength
training should not be used as a replacement for other
exercise but as an adjunct to other weight-bearing aerobic
activities.

EXERCISE IN OSTEOPOROSIS TREATMENT
181
mineral status of young women: A randomized exercise inter- 21. Frost HM 1990 Skeletal adaptations to mechanical usage
vention trial. J Bone Miner Res 7:761–769.
(SATMU): 2. Redefining Wolff’s Law: The remodeling prob-
15. Vuori I, Heinonen A, Sievanen H, Kannus P, Pasanen M, Oja
lem. Anat Rec 226:414–422.
PP 1994 Effects of unilateral strength training and detraining 22. Pruitt LA, Jackson RD, Bartels RL, Lehnhard HJ 1992
on bone mineral density and content in young women: A study
of mechanical loading and deloading on human bones. Calcif
Tissue Int 55:59–67.
Weight-training effects on bone mineral density in early post-
menopausal women. J Bone Miner Res 7:179–185.
23. Seals DR, Hagberg JM, Hurley BF, Ehsani AA, Holloszy JO
1984 Endurance training in older men and women. I. Cardio-
vascular responses to exercise. J Appl Physiol 57:1024–1029.
16. Friedlander AL, Genant HK, Sadowsky S, Byl NN, Gluer CC
1995 A two-year program of aerobics and weight training
enhances bone mineral density of young women. J Bone Miner 24. Hatori M, Hasegawa A, Adachi H, Shinozaki A, Hayashi R,
Res 10:574–585.
Okano H, Mizunuma H, Murata K 1993 The effects of walking
at the anaerobic threshold level on vertebral bone loss in
postmenopausal women. Calcif Tissue Int 52:411–414.
17. Lohman T, Going S, Pamenter R, Hall M, Boyden T, Houtk-
ooper L, Ritenbaugh C, Bare L, Hill A, Aickin M 1995 Effects
of resistance training on regional and total bone mineral den-
sity in premenopausal women: A randomized prospective
study. J Bone Miner Res 10:1015–1024.
18. Nelson ME, Fiatorone MA, Morganti CM, Trice I, Greenberg
RA, Evans WJ 1994 Effects of high-intensity strength training
on multiple risk factors for osteoporotic fractures. JAMA
272:1909–1914.
19. Kerr DA, Morton A, Dick I, Prince R 1996 Exercise effects on
bone mass in postmenopausal women are site specific and
strain dependent. J Bone Miner Res 11:218–225.
20. McCardle WD, Katch FI, Katch V 1986 Exercise Physiology:
Address reprint requests to:
D.A. Kerr
School of Public Health
Curtin University of Technology
GPO Box U1987
Perth 6845, Western Australia
Energy Nutrition, and Human Performance, 2nd ed. Lea & Received in original form November 8, 1999; in revised form July
Febiger, Philadelphia, PA, USA. 31, 2000; accepted September 12, 2000.