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Background. Higher protein diets are promoted for effective weight loss. Striated tissues in omnivorous diets contain high-quality protein, but limited data exist regarding their effects on bone. Methods. To examine the effects of energy restriction--induced weight loss with higher protein omnivorous diets versus lower protein vegetarian diets on bone mineral density in overweight postmenopausal women, two randomized controlled feeding studies were conducted. In Study 1.28 women consumed 750 kcal/day energy deficit diets with 18% energy from protein via lacto-ovo vegetarian sources (normal protein, n = 15) or 30% energy from protein with 40% of protein from lean pork (higher protein, n = 13, omnivorous) for 12 weeks. In Study 2, 54 women consumed their habitual diet (control, n = 11) or 1,250 kcal/day diets with 16% energy from nonmeat protein sources (n = 14) or 26% energy from protein, including chicken (n = 15) or beef (n = 14) for 9 weeks. Results. Study I: With weight loss (normal protein -11.2%, higher protein -10.1%), bone mineral density was not significantly changed in normal protein (-0.003 [+ or -] 0.003 g/[cm.sup.2], -0.3 %) but decreased in higher protein (- 0.0167 [+ or -] 0.004 g/[cm.sup.2], -1.4%, group-by-time p < .05). Study 2: The control, nonmeat, chicken, and beef groups lost 1.5%, 7.7%, 10.4%, and 8.1% weight and 0.0%, 0.4%, 1.1%, and 1.4% bone mineral density, respectively. The change of bone mineral density was significant for chicken and beef compared with the control (group-by-time, p < .05). Markers of calcium metabolism and bone homeostasis in blood and urine were not changed over time or differentially affected by diet. Conclusion. Consumption of higher protein omnivorous diets promoted decreased bone mineral density after weight loss in overweight postmenopausal women. Key Words: Protein--Weight loss--Bone mineral density. doi: 10.1093/geron/glq083

Sherk, VD, Bemben, MG, and Bemben, DA. Comparisons of bone mineral density and bone quality in adult rock climbers, resistance trained men, and untrained men. J Strength Cond Res 24(9): 2468-2474, 2010--The nature of muscular contractions and episodes of impact loading during technical rock climbing are often varied and complex, and the resulting effects on bone health are unclear. The purpose of this study was to compare total body, lumbar spine, proximal femur, and forearm areal bone mineral density (aBMD) and tibia and forearm bone quality in male rock climbers (RC) (n = 15), resistance trained men (RT) (n = 16), and untrained male controls (CTR) (n = 16). Total body, anteroposterior (AP) lumbar spine, proximal femur, and forearm aBMD and body composition were measured using dual-energy X-ray absorptiometry (DXA) (Lunar Prodigy, v. 10.50.086; GE Healthcare, Waukesha, Wisconsin, U.S.A.). Volumetric BMD (vBMD), bone content, bone area, and muscle cross-sectional area (MCSA) of the tibia and forearm were measured using pQCT (peripheral quantitative computed tomography; Stratec XCT 3000, Pforzheim, Germany). No significant group differences were seen in bone-free lean body mass. CTR had significantly (p < 0.05) greater body fat % than RC and RT and significantly (p < 0.05) greater fat mass than RC. Lumbar spine and femoral neck aBMD were significantly (p < 0.05) greater in RT compared to both RC and CTR. RC had significantly (p < 0.05) lower aBMD at the 33% radius site than CTR. Forearm MCSA was significantly (p < 0.05) lower in CTR than in the other groups. No significant differences were seen between groups for vBMD or bone area of the tibia and forearm. In conclusion, resistance-trained men had higher bone density at the central skeletal sites than rock climbers; however, bone quality variables of the peripheral limbs were similar in rock climber and resistance-trained groups. KEY WORDS bone mass, mechanical loading, pQCT, fat mass, bone-free lean body mass

This is a novel descriptive study to characterize oft-season, preseason, and postseason bone and body composition measures in women collegiate athletes. From 2006 through 2008, 67 women collegiate athletes from 5 sports, softball (n = 17), basketball (n = 10), volleyball (n = 7), swimming (n = 16), and track jumpers and sprinters (n = 17) were scanned using dual energy X-ray absorptiometry (DXA) at 3 seasonal periods: (a) oft-season = before preseason training, (b) preseason = after preseason training, and (c) postseason = after competitive season. Dual energy X-ray absorptiometry scans were analyzed for total body mass, lean mass (LM), fat mass (FM), percent body fat (%BF), bone mineral content, bone mineral density (BMD), arm BMD, leg BMD, pelvis BMD, and spine BMD. Data were analyzed between sports using analysis of variance (ANOVA) with Tukey post hoc follow-ups, and within each sport using repeated-measures ANOVA and LSD; [alpha] < 0.05. Significant oft-season to preseason or postseason changes in %BF, LM, and BMD within each sport were as follows, respectively: softball, - 7, +4, +1%; basketball, -11, +4, +1%; volleyball, unchanged, unchanged, +2%; swimming, unchanged, +2.5%, unchanged; track jumpers and sprinters, -7, +3.5, +1%. Comparisons among athletes in each sport showed bone measurements of swimmers averaged 4-19% lower than that of athletes in any other sport, whereas for track jumpers and sprinters, %BF and FM averaged 36 and 43% lower compared with other sports at all seasonal periods. Values for athletes playing basketball and volleyball were most similar, whereas softball athletes' values fell between all other athletes. These data serve as sport-specific reference values for comparisons at in-season and oft-season training periods among women collegiate athletes in various sports. KEY WORDS DXA, division I, season, female, morphology

J Strength Cond Res 24(1): 213-21 7,2010--This study evaluated impulse (I), peak ground reaction forces (GRF), and the rate of force development (RFD) of a variety of exercise modes for the purpose of estimating the magnitude and rate of mechanical loading as a measure of osteogenic potential. Twenty-three subjects participated in this study (mean [+ or -] SD, age 21.2 [+ or -] 1.4 years; body mass 77.8 [+ or -] 16.2 kg). Kinetic data were obtained via a force platform for the test exercises modes, which included walking, jogging, depth jumps, loaded jump squats, and the back squat. Repeated measures analysis of variance revealed significant main effects for I, GRF, and RFD (p [less than or equal to] 0.001). Bonferroni-adjusted post hoc analyses demonstrated that I and GRF were different between each exercise mode and that RFD was different between all exercise modes except for jogging and the back squat. The depth jump demonstrated the highest GRF and RFD, while the back squat produced the highest I. The jump squat produced the second highest value for all the variables assessed. Thus, the depth jump, jump squat, and back squat appear to offer the greatest potential as osteogenic stimuli and a mixed mode training strategy including exercises such as these is recommended. These results suggest that walking and jogging may have less osteogenic potential. KEY WORDS ground reaction forces, resistance training, plyometrics, maximal power training, osteogenesis, bone

Introduction: Weight-bearing exercise during growth enhances peak bone mass. However, the window of opportunity for optimizing positive effects of exercise on peak bone mass remains to be fully defined. Ballet dancing provides a model of mechanical loading patterns required to site-specifically modulate bone. Methods: We assessed the effects of ballet dancing on bone mineral accrual in female non-elite dancers and normally active controls for 3 years across puberty. We recruited 82 ballet dancers and 61 controls age 8-11 years at baseline. Participants were measured over 3 consecutive years; however, the overlap in ages allowed analysis of the groups across 8-14 years of age. We annually assessed bone mineral content (BMC) at the total body (TB), including upper and lower limb regions, and biannually assessed BMC at the proximal femur and lumbar spine (LS) using dual x-ray absorptiometry (DXA). We derived TB lean mass and fat mass from DXA TB scans. Anthropometry, exercise levels, and calcium intake were also measured biannually. Maturational age was determined by age at peak height velocity (PHV). A multilevel regression model was used to determine the independent effects of body size, body composition, maturation, exercise levels, and calcium intake at each measurement occasion. Results: When adjusted for growth and maturation, dancers had significantly greater BMC at the TB, lower limbs, femoral neck (FN), and LS than controls. Excepting the FN region, these differences became apparent at 1 year post-PHV, or the peripubertal years, and by 2 years post-PHV the differences represented a cumulative advantage in dancers of 0.6-1.3% (p Keywords Bone mineral accrual * Exercise * Girls * Growth * Longitudinal

Introduction: Statins are drugs that inhibit HMG Co-A reductase and have been shown to enhance bone formation in vitro and in vivo in rodents. However, the statins currently used for cholesterol-lowering have been selected for their capacity to target the liver where their effects on cholesterol synthesis are mediated and they undergo first pass metabolism. When given in lipid-lowering doses, these agents do not likely reach sufficient blood concentrations to reliably cause substantial increases in bone formation in humans. Moreover, statins are inactivated by cytochrome P450 enzymes, resulting in even less peripheral distribution of the biologically active moieties beyond the liver. Method: To investigate whether an alternate method of administration might produce beneficial effects on bone formation, we administered lovastatin by dermal application to rats to circumvent the first-pass effects of the gut wall and liver. Results: We found that the statin blood levels measured by HMG Co-A reductase activity were higher, maintained longer and less variable following transdermal application than those following oral administration. Also the increased circulating statin levels were associated with significantly enhanced biological effects on bone. After only 5 days of administration of transdermal lovastatin to rats, there was a 30-60% increase in trabecular bone volume, and 4 weeks later, we observed more than a 150% increase in bone formation rates. There was also a significant increase in serum osteocalcin, a marker of bone formation. We also found that lovastatin administered transdermally produces these profound effects at doses in the range of 1% of the oral dose, without any evidence of the hepatotoxicity or myotoxicity that can occur following oral statin administration. Several doses (0.01-5 mg [kg.sup.-1] [day.sup.-1]) and dosage schedules were examined, and collectively the data strongly suggest a powerful anabolic effect but with an unusually flat dose-response curve. Conclusion: These results show transdermal application of statins produces greater beneficial effects on bone formation than oral administration does. Keywords BMP2 * Bone formation * HMG CoA reductase inhibitors * Postmenopausal osteoporosis * Statins . Transdermal delivery

Introduction: The objective of this study was to determine the effect of a moderate reduction of dietary magnesium [50% of nutrient requirement (50% NR)] on bone and mineral metabolism in the rat, and to explore possible mechanisms for the resultant reduced bone mass. Methods: Female rats were 6 weeks of age at the start of study. Serum magnesium (Mg), calcium (Ca), parathyroid hormone (PTH), 1,25[(OH).sub.2]-vitamin D, alkaline phosphatase, osteocalcin, and pyridinoline were measured during the study at 3- and 6-month time points in control (dietary Mg of 100% NR) and Mg-deficient animals (dietary Mg at 50% NR). Femurs and tibias were also collected for mineral content analyses, micro-computerized tomography, histomorphometry, and immunohistochemical localization of substance P, TNF[alpha], and IL-1[beta] at 3 and 6 months. Results: Although no significant change in serum Mg was observed, Mg deficiency developed, as assessed by the reduction in bone Mg content at the 3- and 6-month time points (0.69 [+ or -] 0.05 and 0.62 [+ or -] 0.04% ash, respectively, in the Mg depletion group compared to 0.74 [+ or -] 0.04 and 0.67 [+ or -] 0.04% ash, respectively, in the control group; p=0.0009). Hypercalcemia did not develop. Although serum Ca level remained in the normal range, it fell significantly with Mg depletion at 3 and 6 months (10.4 [+ or -] 0.3 and 9.6 [+ or -] 0.3 mg/dl, respectively, compared to 10.5 [+ or -] 0.4 and 10.1 [+ or -] 0.6 mg/dl, respectively, in the control group; p=0.0076). The fall in serum Ca in the Mg-depleted animals was associated with a fall in serum PTH concentration between 3 and 6 months (603 [+ or -] 286 and 505 [+ or -] 302 pg/ml, respectively, although it was still higher than the control). The serum 1,25[(OH).sub.2]-vitamin D level was significantly lower in the Mg depletion group at 6 months (10.6 [+ or -] 7.1 pg/ml) than in the control (23.5 [+ or -] 12.7 pg/ml) (p Keywords Inflammatory cytokines * Magnesium * Osteoporosis * PTH * Substance P * 1,25[(OH).sub.2]-Vitamin D

Background. Results of cross-sectional analyses of the association of kidney function with bone mineral density (BMD) have been conflicting. We examined the association of cystatin-C, a new marker of kidney function that is unrelated to lean mass, with initial and follow-up BMD, in an ancillary study of the Cardiovascular Health Study, a population-based cohort of individuals >65 years old. Methods. Two years after measurement of cystatin-C and other covariates, the first BMD was measured in Pittsburgh, Pennsylvania and Davis, California, by using dual energy x-ray absorptiometry. Follow-up BMD was measured in Pittsburgh 4 years later. Associations of cystatin-C with initial BMD and the change in BMD (%/y) at the hip were examined with linear regression. Analyses were conducted separately for men and women. Results. In 1519 participants who had cystatin-C and initial BMD assessed, 614 had follow-up BMD. The percent annual change in BMD at the total hip by cystatin-C quartiles was -0.24, 4.13, -0.40, and -0.66%/y (first to fourth quartile) in women and -0.02, -0.30, -0.18, and -0.94%/y in men. After adjusting for potential confounders, cystatin-C was marginally associated with initial BMD in men but not women. Cystatin-C was associated with bone loss in men; after adjustment for weight loss, cystatin-C was not associated with bone loss in women. Conclusion. Kidney dysfunction, as assessed by cystatin-C, is associated with a more rapid loss of BMD at the hip, especially in men. Further studies are needed to confirm these findings and to determine whether this loss leads to an elevated risk of fracture.

Introduction: The purpose of this study was to evaluate the effects of alendronate (ALN) on bone mineral density (BMD) and bone turnover markers in patients with orthotopic liver transplantation (OLT). Methods: In the prospective, controlled, open study with 24 months of follow-up, 98 patients with OLT were randomised to receive ALN 70 mg weekly or no ALN; calcium (Ca) 1,000 mg daily and 0.5 mcg calcitriol daily were provided to all patients. Lumbar spine (LS) and hip BMDs were measured at 6-month intervals by dual-energy X-ray absorptiometry (DEXA). Spinal radiographs were obtained to assess vertebral fractures. Additionally, bone turnover markers, serum parathyroid hormone (PTH) and biochemical parameters were determined every 3 months. Results: Compared with the control group, the ALN group showed significant increases in BMD of the LS (5.1 [+ or -] 3.9% vs 0.4 [+ or -] 4.2%, p Keywords Alendronate * Bone fractures * Bone turnover * Liver transplantation * Osteoporosis

There is conflicting information on the physiological role of growth hormone (GH) in the control of aging. This study reports dual-energy x-ray absorptiometry (DXA) measurements of body composition and bone characteristics in young, adult, and aged long-lived GH receptor knockout (GHR-KO) and normal mice to determine the effects of GH resistance during aging. Compared to controls, GHR-KO mice showed an increased percentage of body fat. GHR-KO mice have reduced total-body bone mineral density (BMD), bone mineral content, and bone area, but these parameters increased with age. In addition, GHR-KO mice have decreased femur length, femur BMD, and lower lumbar BMD compared to controls in all age groups. These parameters also continued to increase with age. Our results indicate that GH resistance alters body composition, bone growth, and bone maintenance during aging in GHR-KO mice.

Byline: Kerry J. Schulze (1,2), Carrie Cutchins (1,3), Beryl J. Rosenstein (1,4), Emily L. Germain-Lee (1,5), Kimberly O. O'Brien (1,2) Keywords: Bone; Ca; Cystic fibrosis; Puberty; IGF-1; Lung function Abstract: Few longitudinal data are available characterizing bone development in adolescents with cystic fibrosis (CF) although this is a critical time for bone mineralization. Dual energy X-ray absorptiometry (DXA) scans were obtained at 1- to 4-year intervals in 18 prepubertal and pubertal girls (age 7--18 years) with CF to determine calcium (Ca) accretion rates and changes (I) in total body bone mineral content (TBBMC) and lumbar spine bone mineral density (LS BMD) Z-scores. Daily Ca acquisition rates were calculated assuming TBBMC was composed of 32.2% Ca. Bone Ca accretion averaged 82 mg/day (2.05 mmol/day) [(range:--38 to +197 mg/day (--0.95 to 4.9 mmol/day)] on [proportional to]1,200 mg/day (30 mmol/day) Ca intakes. Estimated mean peak Ca accretion was 160 mg/day (4 mmol/day) at age 13 years losses of bone Ca occurred in late puberty. Gains in insulin-like growth factor 1 (IGF-1) predicted Ca accretion (p&lt 0.06). Body mass index (BMI) Z-score predicted LS BMD and TBBMC Z-score cross-sectionally but did not predict ITBBMC Z-score. Changes in TBBMC Z-score paralleled Ca accretion rates with age. Bone Ca accretion in girls with CF fell below rates in healthy girls during prepuberty and late puberty despite Ca intakes approaching recommendations. IGF-1 and BMI Z-scores may identify children with CF at risk of compromised bone accretion, and more data are required to elucidate roles of lung function and glucocorticoid use in compromised bone health. Author Affiliation: (1) Center for Human Nutrition, Johns Hopkins University School of Medicine, Department of Pediatrics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA (2) Johns Hopkins Bloomberg School of Public Health, Center for Human Nutrition, Room W2041, 615 Wolfe Street, Baltimore, MD, 21205-2179, USA (3) Johns Hopkins Bloomberg School of Public Health, Department of International Health, 615 N. Wolfe Street, Baltimore, MD, 21205-2179, USA (4) Department of Pediatric Pulmonary Medicine, The Johns Hopkins University School of Medicine, Park Building 315, 600 N. Wolfe Street, Baltimore, MD, 21287, USA (5) Pediatric Endocrinology, Johns Hopkins University School of Medicine, Park Building 211, 600 N. Wolfe Street, Baltimore, MD, 21287, USA Article History: Registration Date: 21/06/2005 Received Date: 01/06/2005 Accepted Date: 18/11/2005 Online Date: 28/02/2006 Article note: Supported by the Cystic Fibrosis Foundation and the National Center for Research Resources (NCRR)/General Clinical Research Center, RR00052, Johns Hopkins Hospital

Background. Lower bone mineral density (BMD) has been documented in clinically depressed populations, and depression is the second most common chronic medical condition in general medical practice. Therefore, the purpose of this study was to determine whether depressive symptoms, vitality, and body weight changes were related to 1-year BMD changes after accounting for covariates. Methods. Healthy postmenopausal women (n = 320; 40-65 years) were recruited, and 266 women completed the study. Participants were 3-10 years postmenopausal, sedentary, and either taking hormone replacement therapy (1-3.9 years) or not taking it (at least 1 year). Exclusion criteria were: current smoking status, history of fractures, low BMD, body mass index >32.9 or Results. Both the vitality and depressive symptoms scores were related to BMD changes at the femur neck but not at the greater trochanter or spine. Weight change was a predictor of BMD changes in the trochanter and spine but not in the femoral neck. Weight change and vitality and/or depressive symptoms had differential and site-specific effects on BMD changes at the hip. Vitality and depressive symptoms related to femoral neck changes and weight change related to greater trochanter changes. Conclusions. The negative impact of depressive symptoms on BMD in this population of postmenopausal women was independent of body weight or other behavioral factors such as calcium compliance or exercise.

The introduction of sit-stand worktables was examined in this study. Purchasers at four companies were interviewed regarding preparations prior to purchase, follow-up after installation, and if expectations had been fulfilled. Personnel at the four companies answered a questionnaire examining use of the worktables' sit-stand function, and the influence of some variables on this. Utilisation of the sit-stand function was less than what could be expected to relieve static musculoskeletal loading during VDU work. Pain experienced during the past year, and education on the use of the worktable gave rise to modest increases in utilisation. Investment in sit-stand worktables was satisfactory to purchasers, in terms of providing flexible furniture to suit modern organisational dynamics. Users were, in general, positive to the worktables, but showed poor compliance in using them. User and purchaser satisfaction with regard to improving individual health ergonomics was questionable in respect of the low level of usage. Keywords: Sit-stand worktables; Ergonomics; VDU work

A comparative, experimental study with repeated measures has been conducted to evaluate the effect of the use of speech recognition on working postures, productivity and the perception of user friendliness. Fifteen subjects performed a standardised task, first with keyboard and mouse and, after a six week training period, with speech recognition. The use of speech recognition leads to improved postures of wrist, forearm, upper arm and shoulder and improvement of neck movements when compared to the use of keyboard and mouse. Although the observation method was basic, this study provides insight into the potential benefits speech recognition has for posture. However, productivity decreased for most subjects and speech recognition appears to be usable for specific tasks only. From the perspective of productivity and the perception of user friendliness further development of speech recognition software is necessary. Up to now, speech recognition seems especially beneficial for people with WMSD complaints. Keywords: Speech recognition; Working postures; Work-related musculoskeletal disorders

A reduction in stature (shrinkage) has been used as a measure of the load on the spine. Musculoskeletal effects of ageing may influence individual responses to compressive loading on the spine and the resultant loss in stature. The aim was to apply the technique of precision stadiometry for assessment of spinal shrinkage in a comparison of responses of two different age groups performing a regimen of circuit weight training. In all, 20 subjects (10 aged 18-25 and 10 aged 47-60 years) participated in the study. Each performed two sets of a 12-station circuit of exercises, the loading being established relative to individual capabilities. Recovery procedures using a semi-supine posture intervened between the two sets and again post-exercise; altogether seven measures of change in stature were obtained using precision stadiometry. The two groups showed a similar pattern of spinal shrinkage, losses in stature being greater for the first set compared to the later set of exercises. Subjects gained height whilst in the formal recovery posture, but responses were inconsistent during warm-up, cool-down and active recovery. Irrespective of age, the spine was less responsive to loading as the duration of activity was increased. It was concluded that provided loading is related to individual capability, healthy older operators are not necessarily compromised by their age in activities that include handling and lifting weights. Keywords: Exercise; Manual handling; Stature; Weight training

Background: In recent years interest in bone densitometry in children has increased. Objective: To evaluate the clinical application of digital X-ray radiogrammetry (DXR) and compare the results with those of dual-energy X-ray absorptiometry (DXA). Materials and methods: A total of 41 children with acute lymphoblastic leukaemia (ALL) and 26 children with growth hormone deficiency (GHD) were included in this longitudinal study. Radiographs of the left hand were obtained and used for DXR. DXA of the total body and of the lumbar spine was performed. Results: In both study populations significant correlations between DXR and DXA were found, and, with the exception of the correlation between DXR bone mineral density (DXR-BMD) and bone mineral apparent density in the GHD population, all correlations had a P-value of Keywords Bone densitometry * DXR * DXA * Child DOI 10.1007/s00247-005-0080-3

Background. Prospective and cross-sectional studies have confirmed a significant association between bone mineral density (BMD) measurements and fracture risk. However, the relationship among incident fracture risk, mortality. BMD, and quantitative ultrasound is controversial and less studied. Methods. At baseline, 275 postmenopausal elderly women were evaluated by clinical questionnaire regarding fracture risk factors and had radiological analysis of the spine, spine and femur dual energy x-ray absorptiometry, and calcaneous quantitative ultrasound measurements. Five years later, 42 (15.3%) women bad died. 25 (9.1%) were lost to follow-up, and 208 (75.6%) continued the study. Specific questionnaire items regarding fracture risk were reevaluated, and thoracic and lumbar spine x-rays were taken to identify new fractures. Causes of mortality in this population were also assessed. All reported deaths were confirmed by review of death certificates or hospital records and were classified according to International Classifications of Diseases, 10th Revision (ICD-10) code. Results. After adjustments for age, weight, body mass index, smoking stains, previous fracture, physical activity, drug use, and presence of chronic diseases, each 1 standard deviation (SO) reduction in stiffness index (SI) at baseline was significantly associated with future fracture (hazard ratio [HR] 2.23: 95% confidence interval [CI]. 1.30-3.83) and total mortality 5 years later (HR = 1.57: 95% CI, 1.10-2.47). Femoral neck and trochanter BMD vales at baseline were also related to new fracture (HR = 2.01: 95% CI, 1.27-3.18 and HR 1.62: 95% CI, 1.08-2.42, respectively) and total mortality (HR 1.44; 95% CI, 1.06-2.22 and HR = 1.59: 95%, CI, 1.07-2.36. respectively). Cardiovascular mortality was associated with decreased baseline femur BMD (HR = 1.28: 95% CI, 1.08-2.26) and lower SI values (HR = 1.54: 95% CI, 1.08-2.79). Conclusions. Our results demonstrate that low femoral BMD and low SI are able to predict fracture risk and are related to non cause specific and cardiovascular mortality, independently of other factors associated with osteoporosis, death. or aging.

Background. The effect of changes in physical exercise on progression of musculoskeletal disability in seniors has rarely been studied. Methods. We studied a prospective cohort annually from 1984 to 2000 using the Health Assessment Questionnaire Disability Index (HAQ-DI). The cohort included 549 participants, 73% men, with average end-of-study age of 74 years. At baseline and at the end of the study, participants were classified as 'High' or ''Low' vigorous exercisers using a cutpoint of 60 min/wk. Four groups were formed: 'Sedentary' (Low [right arrow] Low; N = 71), 'Exercise Increasers' (Low [right arrow] High; N = 27), 'Exercise Decreasers' (High [right arrow] Low; N = 73), and 'Exercisers' (High [right arrow] High; N = 378). The primary dependent variable was change in HAQ-DI score (scored 0-3) from 1984 to 2000. Multivariate statistical adjustments using analysis of covariance included age, gender, and changes in three risk factors, body mass index, smoking status, and number of comorbid conditions. Participants also prospectively provided reasons for exercise changes. Results. At baseline, Sedentary and Increasers averaged little exercise (16 and 22 exercise min/wk), whereas Exercisers and Decreasers averaged over 10 times more (285 and 212 exercise min/wk; p < .001). All groups had low initial HAQ-DI scores, ranging from 0.03 to 0.08. Increasers and Exercisers achieved the smallest increments in HAQ-DI score (0.17 and 0.11) over 16 years, whereas Decreasers and Sedentary fared more poorly (increments 0.27 and 0.37). Changes in HAQ-DI score for Increasers compared to Sedentary, were significantly more favorable (p < .05) even after multivariate statistical adjustment. Conclusions. Inactive participants who increased exercise achieved excellent end-of-study values with increments in disability similar to those participants who were more active throughout. These results suggest a beneficial effect of exercise, even when begun later in life, on postponement of disability.

The subjects of this study (n = 20; 16 women, 4 men) performed 10 weeks of leg press training using one of two exercise modes (isoload or isotonic) with no crossover. Their workouts, which were performed 3 times per week, involved 4 sets of 8 repetitions with maximal voluntary effort. Testing was performed pre- and posttraining to examine bone and muscle changes. Posttraining, both groups incurred significant concentric knee extensor strength and leg muscle mass gains, while the percentage of body fat and total body fat mass each decreased. Leg and total body bone mineral densities showed group-by-time interactions, as isoload exercise caused posttraining gains, while isoinertial values were unchanged. Bone resorption assays showed insignificant changes. Isoload training likely involved greater strain magnitudes and rates to evoke higher peak forces and osteogenesis. Transduction of the training stimulus may have involved (a) formation in response to microdamage, and (b) piezoelectric-induced potentials that stimulated site-specific osteoblast activity and osteogenesis. Key Words. isoinertial, isoload, osteogenesis, weight training

Byline: Tuan V. Nguyen (1,2), Jacqueline R. Center (1), John A. Eisman (1) Keywords: Bone mineral density; Fracture risk; Ultrasound; Women Abstract: Osteoporotic fracture is considered to result from reduced bone strength and to be related to decreased bone mass and impaired bone architecture. Quantitative ultrasound measurements (QUS) of bone, that may reflect certain architectural aspects of bone, have been shown to be associated with fracture, but it is not clear whether the association is independent of bone mineral density (BMD). This study was designed to examine the contributions of cortical QUS and BMD measurements to the prediction of fracture risk in postmenopausal Caucasian women. Speed of sound (SOS) at the distal radius, tibia, and phalanx (Sunlight Omnisense) and BMD at the lumbar spine and femoral neck (GE Lunar) were measured in 549 women, aged 63.2 +- 12.3 years (mean +- SD range, 49--88 years), including 77 fracture cases. Lower SOS at the distal radius, tibia, and phalanx, which were correlated with each other, were associated with increased risk of fracture. Independent predictors of fracture risk (in multivariate analysis) were distal radius SOS (OR per SD = 1.8 95% CI, 1.3--2.4), femoral neck BMD (OR per SD = 1.9 95% CI, 1.4--2.4), and age (OR per 5 years = 1.2 95% CI, 1.0--1.5). Approximately 30% of the women had distal radius SOS T-scores &lt -2.5 however, only 6.6% of women had both BMD and SOS T-scores &lt -2.5. Among the 77 fracture cases, only 14 (18.2%) had both BMD and QUS T-scores below -2.5. These data in postmenopausal women suggest that speed of sound at the distal radius was associated with fracture risk, independent of BMD and age. The combination of QUS and BMD measurements may improve the accuracy of identification of women who will sustain a fracture. Author Affiliation: (1) Bone and Mineral Research Program, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, Australia (2) Bone and Mineral Research Program, Garvan Institute of Medical Research, 384 Victoria Street, NSW 2010, Darlinghurst, Australia Article History: Registration Date: 09/07/2004 Received Date: 21/07/2003 Accepted Date: 09/02/2004 Online Date: 07/08/2004