Arm Bone Mineral Density Research Articles

The muscle strength and bone density relationship in young women: Dependence on exercise status

Numerous studies report an association between muscle strength and bone mineral density (BMD) in young and older women. However, the participants are generally non-athletes, thus it is unclear if the relationship varies by exercise status. Therefore, the purpose was to examine the relationships between BMD and muscle strength in young women with markedly different exercise levels.cross-sectional.a University research laboratory.18 collegiate gymnasts and 22 age- and weight-matched recreationally active control women.lumbar spine, femoral neck, arm, leg and whole body BMD (g/cm(2)) were assessed by dual X-ray absorptiometry. In addition, lumbar spine and femoral neck bone mineral apparent density (BMAD, g/cm(3)) was calculated. Handgrip strength and knee extensor and flexor torque (60 degrees /s) were determined by dynamometry, and bench press and leg press strength (1-RM) using isotonic equipment.BMD at all sites and bench press, leg press and knee flexor strength were greater in gymnasts than controls (p<0.001). In controls, knee extensor torque was significantly correlated to femoral neck, limb and whole body BMD (r=0.47-0.55, p<0.05), leg press strength was associated with limb and whole body BMD (r=0.52-0.74, p<0.05), and bench press strength with arm BMD (r=0.50, p=0.019). In partial correlations controlling for weight, leg press strength was related to leg and whole body BMD (r=0.46-0.63, p<0.05). There was no association between muscle strength and BMD in gymnasts.These results suggest that the association between muscle strength and BMD in young women is dependent on exercise status. The osteogenic effect of increased mechanical loading associated with gymnastics training likely contributes to the dissociation of the relationship in gymnasts.

Difference in the effects of body composition on bone mineral density between pre- and postmenopausal women

Objective: This study was to investigate whether the effect of lean and fat mass component on bone mineral density (BMD) differs between pre- and postmenopausal women. Materials and methods: Subjects were 360 pre- and 193 postmenopausal Japanese women with right side dominance. Age, height, and years since menopause (YSM, in postmenopausal women) were recorded. Body fat and lean body mass were measured by whole body scanning with dual-energy X-ray absorptiometry (DEXA). BMD of the vertical axis (L2-4 of the lumbar spine, pelvis, bilateral legs, and total body) and horizontal axis (arms) were also measured by DEXA. Results: In premenopausal women, lean body mass was independently correlated with BMD of the left arm (partial correlation coefficient=0.417), right arm (0.430), L2-4 (0.285), pelvis (0.276), left leg (0.403), right leg (0.412), and total body (0.377) ( P<0.001). However, body fat mass was not correlated with several BMD sites except for pelvis BMD (0.187, P<0.01). In postmenopausal women, body fat mass was independently correlated with BMD of the left arm (0.248, P<0.01), L2-4 (0.188, P<0.05), pelvis (0.263, P<0.01), left leg (0.228, P<0.01), right leg (0.319, P<0.001), and total body (0.188, P<0.01)). However, lean body mass was correlated with BMD in only three segmental regions including left arm (0.175), right arm (0.217), and left leg (0.210; P<0.05). Conclusion: Lean body mass is a significant determinant of BMD in premenopausal women, while body fat mass is a significant determinant in postmenopausal women.

Prospective Analysis of Body Composition and SF36 Profiles in Professional Dancers over a 7-Month Season: Is There a Correlation to Injury?

This IRB-approved, prospective study evaluated body composition, strength, diet, lifestyle factors, and the incidence of injuries in professional dancers. Measurements were obtained from 15 dancers (6 males, 9 females) before a 7-month dance season and 13 dancers (5 males, 8 females) at the end of the season. Body composition was analyzed using dual x-ray absorptiometry. Quality-of-life variables were measured using the SF36 general health status survey. Post-season bone mineral density (BMD) for arms, trunk, ribs, pelvis, and total body for females was statistically significantly greater than preseason values. Total tissue mass for arms decreased significantly. No other body composition changes for females or males were observed, though striking differences were found when comparing dancers to age-matched and weight-matched non-dancers. Total body percent fat for female dancers was 43% lower than non-dancers, while lean mass was greater. Arm and spine BMD was lower than non-dancers but BMD for legs was significantly higher. For male dancers, there was significantly lower total body fat, greater lean mass in legs, and greater total body BMD than non-dancers. Grip strength did not change (preseason to post-season). Dietary profiles varied greatly, although most dancers met estimated minimum caloric requirements. Eleven dancers (85%) suffered injuries during the course of the season. There were no significant correlations between injury rate and body composition or lifestyle variables. All dancers scored significantly lower than population norms for the perception of pain. In summary, dancers maintained their body composition profiles despite the physical and emotional rigors of the dance season, and BMD actually increased significantly in females. The bodily pain score on the SF36 documents the impact of chronic injuries.

Paradoxical adaptation of mature radius to unilateral use in tennis playing

The positive effects of physical activity on human bone mass have been well documented in many cross-sectional studies comparing athletes with sedentary controls as well as in longitudinal follow-up. By applying peripheral quantitative computed tomography (pQCT), which has the advantage of measuring volumetric bone mineral density (BMD) and the ability to distinguish among trabecular and cortical components, it was demonstrated that cortical BMD of the dominant arm was not greater than that of the nondominant arm. Cortical drift toward the periosteal direction and an increase in cortical thickness resulted in an improvement of mechanical characteristics of the playing arm’s midradius. An improvement in the mechanical properties of young adult bone in response to long-term exercise was therefore related to geometric adaptation, but not to an increase in BMD. The manner in which the recruitment and function of bone cells are coordinated differs between the growing and the nongrowing skeleton. In the former, modeling is the dominant mode, and in the latter it is remodeling. In the present study, the side-to-side difference of 92 middle-aged female tennis players who initiated training after bone had matured was analyzed by pQCT. The side-to-side difference detected suggested a paradoxical adaptation of the mature radius to unilateral use during tennis playing, and that tennis playing after bone had matured did not stimulate cortical drift in the periosteal direction, unlike that seen in young subjects. Unexpectedly, the cross-sectional areas (periosteal and endocortical area) of the radius were smaller in the dominant arm than in the nondominant arm in the middle-aged female players. The findings suggest that unilateral use of the arm after the third decade of life suppresses age-related changes in bone geometry.

Side-To-Side Comparisons of Bone Mineral Density in Upper and Lower Limbs of Collegiate Athletes

This cross-sectional study investigated the effects of participation in various sports on side-to-side (contralateral) differences in bone mineral density (BMD) of the upper and lower limbs. The BMD of the arms and legs was measured using dual energy X-ray absorptiometry. The subjects were 184 collegiate athletes, both men and women, who participated in NCAA Division I-A baseball, basketball, football, golf, soccer, tennis, cross-country, indoor/outdoor track, and volleyball. Results revealed greater BMD of the right arms compared with the left arms for all teams, with the most pronounced differences observed in men's and women's tennis and men's baseball. Differences in the lower limbs were less common. No significant differences in lower limb BMD were found in the women. In men, differences in lower limb BMD were found in the football and tennis teams, with the nondominant leg having greater bone mass. Recognition of contralateral differences in bone density may be of particular interest to strength and conditioning professionals as they consider the need to include bilateral and unilateral training programs in an effort to maximize performance and minimize stress-related injuries.

Effect of Subclinical Hypothyroidism and Obesity on Whole-Body and Regional Bone Mineral Content

Objective: The present investigation was aimed to evaluate the effect of subclinical hypothyroidism and obesity on bone mineral content (BMC) in different body segments. Methods: Thirty-two premenopausal women (age: 37 ± 9.9 years), with a wide range in body mass index (BMI), were studied. Subclinical hypothyroidism was defined by a basal TSH ≧4 µU/l and/or a TRH-stimulated peak ≧30 µU/l. For each subject, weight, height, BMI (weight/height²) and the waist/hip ratio were measured. Total BMC, total bone mineral density (BMD), leg BMC, leg BMD, trunk BMC, trunk BMD, arm BMC and arm BMD were determined using dual-energy X-ray absorptiometry. Thyroid function (basal and TRH-stimulated TSH, free T₃ and free T₄) were determined from fasting blood samples for all subjects. Results: Anova was conducted within all the groups to observe the effect of thyroid status and/or obesity on BMC and BMD. There was no statistical difference for age. Total BMC was affected by obesity (p < 0.05) but not by thyroid status, BMD of the legs was significantly influenced both by thyroid function and obesity (p < 0.01); total BMD was affected by hypothyroid status (p < 0.05). A direct relationship between leg BMD and TSH was demonstrated. Conclusion: Subclinical thyroid hypofunction and obesity seem to affect BMD differently in the body segments. An influence of gravitational force seems necessary in order to make evident the effect of subclinical hypothyroidism on bone. A condition of subclinical hypothyroidism should be considered when evaluating subjects for osteoporosis, since a BMD measured at the femoral neck may induce underestimation of initial osteoporosis.

Relationship of androgens to muscle size and bone mineral density in women with polycystic ovary syndrome

OBJECTIVE: To investigate the relationship of androgens to regional muscle size and bone mineral density (BMD) in women with polycystic ovary syndrome (PCOS). METHODS: Seventy-one amenorrheic and right-side dominant women with PCOS (mean age ± standard deviation 28.1 ± 6.7 years) were enrolled. Baseline characteristics included age, height, weight, and body mass index (BMI). Regional BMD and lean mass were measured by whole-body scanning with dual-energy x-ray absorptiometry. Serum levels of testosterone, dehydroepiandrosterone sulfate (DHEAS), and androstenedione were measured by radioimmunoassay. Correlations between regional BMD and variables were investigated using a Pearson correlation test and multiple regression analysis. RESULTS: Serum testosterone levels correlated significantly with lean mass of the left arm, right arm, trunk, left leg, and right leg ( r = .34, P < .05 to r = .50, P < .01). Regional lean mass correlated significantly with respective regional BMD ( r = .30, P < .05 to r = .68, P < .001). These relationships remained significant after adjusting for age, height, and weight. Serum testosterone levels were not correlated with BMD of the bilateral arms and lumbar spine. Although serum testosterone levels correlated with leg BMD ( r = .34, P < .05 to r = .45, P < .01), significance did not persist after adjusting for respective regional lean mass. CONCLUSION: Testosterone influences regional BMD through increasing regional muscle mass in women with polycystic ovary syndrome.

The duration of exercise as a regulator of bone mass

Exercise is associated with increased peak bone mineral density (BMD). To determine the relationship between the duration of exercise and BMD, we measured BMD of the axial and appendicular skeleton by dual-energy X-ray absorptiometry (DXA), and speed of sound (SOS), broadband attenuation (BUA), and stiffness index by quantitative ultrasound (QUS) of the calcaneus, in 67 active male national soccer players (mean age 23 years, range 17–35), which included 23 premier-league players exercising 12 h/week (range 8–18), 23 third-league players exercising 8 h/week (range 3–18), and 21 sixth-league players exercising 6 h/week (range 2–10). Results were compared with 24 sedentary age- and gender-matched controls and presented as mean ± SEM. BMD was higher in all weight-bearing regions for the whole group relative to controls (BMD: total body 6.8 ± 0.7%, leg 9.6 ± 0.8%, lumbar spine 13.2 ± 1.2%, femoral neck 12.7 ± 1.2% [all p < 0.001]; calcaneus SOS 4.2 ± 0.3%, BUA 8.7 ± 1.5%, and stiffness index 24.2 ± 2.0% [all p < 0.01]). No differences were found in head or arm BMD. There were no differences in BMD or QUS measurements when comparing soccer players exercising for different activity durations. Duration of activity correlated with BMD weight-loaded regions and with QUS, provided it was less <6 h/week ( p < 0.01 respectively), but not when exercising more frequently. Femoral neck BMD increased by 3.3% across every hour increase in activity in those with 0–6 h of exercise/week and by 0.7% in those exercising more than this ( p < 0.01). We conclude that, in national-league soccer, the BMD needed to attain a bone strength commensurate with that of duration of activity is achieved by 6 h of exercise per week. Beyond this, additional exercise confers no higher BMD. The skeleton adapts to the prevalent level of exercise intensity required and no further.

Total and regional bone density in male runners, cyclists, and controls.

Male athletes who were runners (N = 12), cyclists (N = 14), or both (N = 13) were compared with nonexercising age-matched controls (N = 23) for total and regional bone mineral density (BMD). All athletic subjects had competed for a minimum of 3 yr and trained for a minimum of 4 h x wk(-1). Runners undertook no cycling and cyclists undertook no running training. All subjects were scanned for whole body and L1-L4 spine BMD using a Hologic QDR 1000W scanner (Hologic Inc., Bedford, MA). There were no differences in age, height, weight, body mass index (BMI), % fat, or hours of training between any of the athletic groups (P > 0.05), although compared with controls, runners and cyclists had lower body mass index (P < 0.01) and all athletic groups had lower % fat (P < 0.001). Compared with controls, runners had greater total and leg BMD (P < 0.05), cyclists had reduced spine BMD (P = 0.05), and athletes of the "both" group had greater total (P < 0.05) and arm BMD (P < 0.01). Running is associated with increased bone density, particularly in the leg, whereas cycling is associated with a mild decrease in bone density in the spine. In athletes who do both, running exerts a stronger influence than cycling.

AGE IMPACTS THE RELATIONSHIP OF SOFT TISSUE MASS TO BONE MINERAL DENSITY

1084 The relative influence of fat and lean tissue mass (LTM) on bone mineral density (BMD) is controversial. Part of the problem may lie in the use of total body BMD were approximately 12% is head BMD. The purpose of this study was to examine the association between BMD and soft tissue mass while accounting for the possible influence of factors such as head BMD, age, and athletic. A cohort of 1020 females, 274 of whom were collegiate athletes, all had total body BMD measurements on the Lunar DPX (version 3.61), from which values for lean and fat tissue mass were obtained along with total, arm, leg, and head BMD. The subjects ranged in age from 6 to 84 years. As expected, athletes had significantly higher BMD compared to age-matched nonathletes at all sites except for the head. Stepwise multiple regression was used to determine the best predictors of total and regional BMD. When all ages were included in the analysis, total LTM was the best predictor of both total body BMD and trunk + limb BMD (total body BMD not including head) while arm and leg LTM were the best predictors of arm and leg BMD with R ranging from .68 to .75. Exclusion of the athletes from the analyses yielded similar results. However, when only those participants older than 45 were analyzed, total fat mass was the best predictor of BMD for all sites including trunk + limb (R = .43 to .44). In conclusion, lean tissue mass appears to exert the most influence on BMD in younger females. However, in older females, total fat mass is a better predictor of BMD, possibly because of a greater peripheral synthesis of estrogen.

REGIONAL BONE MINERAL DENSITY PATTERN IN MARATHON RUNNERS

1184 The effect of intense, chronic exercise on bone mineral density is unclear. To clarify the effects of marathon training on patterns of bone mineral density (BMD), we compared regional Z scores of 11 national class male marathon runners (best mean marathon time of 2 hours 35 (±8.7) min) using dual energy x-ray absorptiometry. Our subjects averaged 29.6 (±3.9) years, had a mean BMI of 20.1 (±1.2) kg/m2, a mean relative fat of 10.5% (±2.8), a mean VO2max (n=10) of 75.8 (±7.1) ml/kg/min, and had been running for 16.7 (±7.1) years, currently averaging 70 (±8) miles per week. The BMD was measured at the lumbar spine (L2-L4), femur, forearm, and total body. Mean Z scores were compared by paired t tests using SPSS with the following results: (Table)TableThe following differences were significant: arm BMD<trunk BMD<leg BMD (p<0.01) and radius 33%<L2-L4<total femur (p<0.03). In contrast to others' results, osteopenia was not found in these subjects at the lumbar spine or proximal femur; two subjects showed osteopenia at the radius 33% site (>1 SD below the mean). These results demonstrate that in highly trained marathon runners, BMD shows a distinct patterned response and is well above age and sex-matched values in skeletal sites experiencing the greatest loading during running.

RELATIONSHIP BETWEEN BONE MINERAL DENSITY, ENERGY INTAKE AND MENSTRUAL STATUS IN ELITE FEMALE GYMNASTS

1187 The purpose of this study was to determine the relationship between nutrient intake and menstrual status on bone mineral density (BMD) in young female elite artistic gymnasts. The measurements were obtained on 33 gymnasts from the United States National Junior and Senior teams. Data were collected on nutrient intake, menstrual status, percent body mass, percent lean mass, and arm, leg, rib, pelvis, spine, trunk, and total BMD. Mean age, height and weight of the subjects were 15.09 yr. (± 1.33), 151.35cm (±7.10), and 46.83kg (±8.27), respectively. Gymnasts who had achieved menses had significantly higher BMD at areas of the arm (p=.013), leg (p=.044), rib (=.045), spine (p=.006), and trunk (p=.015) than those gymnasts who had not achieved menses. Gymnasts had significantly lower average kcal intakes when compared to the RDAs (p=.000). Those gymnasts who achieved menarche consumed significantly fewer kcals than those who had not achieved menses in both average kcal intake determined from the food records (p=.010) and timeline average kcal intake (p=.009). Furthermore, those gymnasts who had achieved menses had significantly higher percent body fat measures than those who had never menstruated. These data suggest that the presence of estrogen and other contributing factors may lead to increases in BMD. Supported by USOC-SST-GYM1-97

Muscle mass and fat mass in relation to bone mineral density in very old men and women: the Framingham Heart Study

Aim of the study was investigate the cross-sectional relationship between body composition and bone mineral density (BMD) in very old men and women. The study sample consisted of 504 women and 285 men, aged 72–93 yr, participating in examination 22 (1992–1993) of the Framingham Heart Study. Total body BMD, regional BMD, and soft-tissue body composition was measured by dual-energy X-ray absorptiometry. Both muscle mass and percentage body fat were positively associated with total body BMD in women. After adjustment for age, physical activity, smoking status, estrogen use, and thiazide use, BMD increased with increasing tertile of muscle mass ( p = 0.007) and with increasing tertile of percentage body fat ( p = 0.0001) in women. In men muscle mass, not percentage body fat, was positively associated with BMD. After adjustment for potential confounders, BMD remained associated with muscle mass only ( p = 0.02). These results were similar for leg BMD and arm BMD. The study suggests that the influence of muscle and fat mass on bone mineral density is different between very old men and women.

Exercise and bone mineral density in mature female athletes

An understanding of the relationship between weight-bearing activity and bone mineral density (BMD) is important in devising strategies to maximize and maintain skeletal strength in the female population, particularly those entering menopause. Three contrasting groups (N = 20) of mature female athletes (42-50 yr) with long-term (> 20 yr) histories of significant training and performance in their chosen sport were studied cross-sectionally. The groups were: (i) high impact sport (netball/basketball; HIGH), (ii) medium impact sport (running/field hockey; MED) and (iii) a nonimpact sport (swimming; NON) and (iv) a nonsport control group (CON; N = 20). Whole body and regional BMD and body composition (fat and lean mass) were measured by dual-energy x-ray absorptiometry. Isometric strength of dominant arm flexors and leg extensors was measured by a strain tensiometer. With an alpha level of significance of 0.05, HIGH showed significantly greater whole body and regional leg BMD than NON or CON. MED registered higher values than CON for whole body and regional leg BMD. Only HIGH had significantly greater leg strength than CON. Regional arm BMD was significantly greater in all exercising groups compared with CON, but no significant difference in arm strength was found between any groups. The athletic groups all had significantly lower body fat and higher height-corrected lean mass than CON. Height-corrected lean mass, height and leg extensor strength, but not calcium intake, arm flexor strength or body fat, were significant predictors of whole body and regional arm and leg BMD. Using the significant predictors as covariates, the impact groups (HIGH/MED) had significantly higher whole body BMD than CON. HIGH also had significantly higher whole body BMD than NON and both impact groups were greater than NON in regional leg BMD. Results suggest that females who participate regularly in the premenopausal years in high impact physical activity tend to have higher BMD than nonathletic controls.

Investigation of bone mineral distribution in Japanese using dual-energy X-ray absorptiometry

To investigate bone mineral distribution in humans, the authors conducted a cross-sectional survey of, and performed bone-density measurements on, 1,310 healthy Japanese ranging in age 5 to 85 years. Eight hundred fifty-eight of the subjects were female, and 452 were male. Arm, leg, and spine bone mineral content (BMC) and bone mineral density (BMD) were assessed by dual-energy X-ray absorptiometry (DXA), and the subjects were divided into 5-year age groups. BMD showed increases with skeletal growth until reaching a peak at 15 to 19 years in females, and 25 to 29 for males. For both sexes the fastest growth to maturity in terms of bone mass values was in the late 20s. Females, though, had higher arm, leg, and spine remodeling rates than males. In premenopausal women no changes in arm, leg or spine BMC and BMD were observed. Postmenopausal women showed an overall reduction in bone mass, most noticeably in the spine. After menopause, women had about 10 years of accelerated loss (1.46%/year). Vertebral BMD values were similar for men and women (1.10 +/- 0.20g/cm2 for males vs. 1.09 +/- 0.14g/cm2 for females, p > 0.05). BMC values were significantly higher in males, and males at all times had a higher arm and leg BMD. There were no significant value differences in either sex for left and right leg BMC and BMD; however, from the age of 15, right arm values were significantly higher likely due to right handedness. For both sexes the order of BMC and BMD was leg, spine, and arm.

A possible role of estrone produced in adipose tissues in modulating postmenopausal bone density.

Estrogen deficiency in postmenopausal women is a major contributing factor to bone loss occurring after menopause. Although serum estradiol levels decrease conspicuously, a considerable amount of estrone still exists in women after natural menopause. Since most of the estrone is converted from androgens in adipose tissues, we attempted to seek interrelationship among serum estrone levels, fat mass and bone mineral density (BMD) in postmenopausal women. Thirty women who underwent natural menopause at the age between 45 and 53 were examined for BMD of head, arms, trunk and legs, as well as total body fat and total lean body mass using a Lunar DPX, a dual energy X-ray absorptiometer. Serum estrone concentration in each subject was measured by RIA. BMD of all sites of bones examined showed a positive correlation with relative fat mass (total body fat/body weight). Serum estrone levels were positively correlated with BMD of arms, trunk and legs, as well as relative fat mass. Multiple regression analysis further demonstrated that relative fat mass and serum estrone levels were significantly related to BMD of both arms and trunk, and BMD of trunk, respectively. These results suggest that estrone produced in adipose tissues may have, if only in part, a role in modulating the loss of bone mass occurring after menopause.

Total body and regional bone mineral content in hemodialysis patients.

Bone mineral content (BMC) in the total body and lumbar spine was evaluated in 126 hemodialysis patients (60 males, 66 females) by dual photon absorptiometry with the Norland DBD 2600. Measurements of: 1) total body BMC divided by lean body mass (BMCTB/LBM), 2) bone mineral density (BMD) of total body, 3) BMD of four regional sections (head, trunk, pelvis, and legs), and 4) BMD of lumbar spine, generally showed a significant decrease in the hemodialysis patients compared to the reference population. However, arm BMD did not show a significant difference between patients and control populations. The z-score of BMCTB/LBM declined significantly throughout the duration of hemodialysis, although that of the lumbar spine BMD did not. It should be noted that the degree of decrease in BMC was more prominent in the total body measurement than in the lumbar spine measurement. There was preferential osteopenia of the total body in the hemodialysis patients. Although the lumbar spine BMD showed a lower value than the control population, the lumbar spine is not the recommended region to monitor the BMD change in hemodialysis patients.

Comparison of bone mineral content and bone mineral density between dominant and nondominant limbs in children 8-16 years of age.

The bone mineral content (BMC), bone mineral density (BMD), and bone free lean tissue (BFLT) of dominant limbs were compared to nondominant values in girls and boys 8-16 years of age (girls, n = 124; boys, n = 110). Results showed that BMC, BMD, and BFLT of the dominant arm was significantly greater than of the nondominant arm (P < .01). The differences were found for both boys and girls and across all age groups except for 8 to 9-year-old boys for BMC. There were no differences in BMC or BMD in the legs, but the dominant leg had significantly greater BFLT than the nondominant leg (P < .01). The greater BMC and BMD values of the dominant arm are likely a result of greater mechanical loading (resulting from normal daily activities) of the dominant arm; this speculation is supported by the greater muscularity in the dominant arm. In the legs it is likely that weight bearing and not bias muscular activity is more important in determining bone mineral status. © 1993 Wiley-Liss, Inc.