Exercise and Bone Mass in Adults

Effects of Body Mass Index on Bone Loading Due to Physical Activity

The aim of the current study was to compare bone loading due to physical activity between lean, and overweight and obese individuals. Fifteen participants (lower BMI group: BMI < 25 kg/m², n = 7; higher BMI group: 25 kg/m² < BMI < 36.35 kg/m², n = 8) wore a tri-axial accelerometer on 1 day to collect data for the calculation of bone loading. The International Physical Activity Questionnaire (short form) was used to measure time spent at different physical activity levels. Daily step counts were measured using a pedometer. Differences between groups were compared using independent t-tests. Accelerometer data revealed greater loading dose at the hip in lower BMI participants at a frequency band of 0.1-2 Hz (P = .039, Cohen's d = 1.27) and 2-4 Hz (P = .044, d = 1.24). Lower BMI participants also had a significantly greater step count (P = .023, d = 1.55). This corroborated with loading intensity (d ≥ 0.93) and questionnaire (d = 0.79) effect sizes to indicate higher BMI participants tended to spend more time in very light activity, and less time in light and moderate activity. Overall, participants with a lower BMI exhibited greater bone loading due to physical activity; participants with a higher BMI may benefit from more light and moderate level activity to maintain bone health.

Longitudinal effects of swimming on bone in adolescents: a pQCT and DXA study

The aims of the present study were, firstly, to evaluate areal bone mineral density (aBMD), bone strength and structure during a swimming season and compare them to those of normo-active controls (CG), and secondly to ascertain whether practising an additional weight-bearing sport other than swimming might improve bone. Twenty-three swimmers who only swam (SWI-PURE; 14 males, 9 females), 11 swimmers who combined swimming with an additional weight-bearing sport (SWI-SPORT; 8 males, 3 females) and 28 controls (CG; 16 males, 12 females) participated in the present study. aBMD was assessed with dual energy X-ray (DXA). Bone mass, area, structure and strength of the non-dominant tibia and radius were measured with peripheral quantitative computed tomography (pQCT). Measurements were performed at the beginning of the swimming season and 8 months later. The only difference among groups for DXA and pQCT variables was found for arm aBMD, which was higher in the SWI-SPORT than in the CG group at both pre- and post-evaluation. Group by time interactions (GxT) were found for trochanter aBMD when comparing SWI-SPORT to CG and SWI-SPORT to SWI-PURE, favouring in both cases SWI-SPORT. No GxT were found for the radius. For the tibia, GxT were found between SWI-SPORT and CG and between SWI-PURE and CG, in both cases favouring the swimmers. A season of swimming does not confer any additional benefits to aBMD, but may confer minor benefits to structure and mass. Complementing swimming with a weight-bearing activity is beneficial to bone.

Exercise for Bone in Childhood-Hitting the Sweet Spot

PURPOSE

The goal of the current work is to challenge the enduring notion that prepuberty is the optimum timing for maximum bone response to exercise in childhood and to present the evidence that early puberty is a more potently receptive period.

METHOD

The relevant literature is reviewed and the causes of the misconception are addressed in detail.

RESULTS

Contrary to prevailing opinion, ample evidence exists to suggest that the peripubertal years represent the developmental period during which bone is likely to respond most robustly to exercise intervention.

CONCLUSION

Public health initiatives that target bone-specific exercise interventions during the pubertal years are likely to be the most effective strategy to harness the increased receptiveness of the growing skeleton to mechanical loading.

Bone mineral density in vocational and professional ballet dancers

According to existing literature, bone health in ballet dancers is controversial. We have verified that, compared to controls, young female and male vocational ballet dancers have lower bone mineral density (BMD) at both impact and non-impact sites, whereas female professional ballet dancers have lower BMD only at non-impact sites.

INTRODUCTION

The aims of this study were to (a) assess bone mineral density (BMD) in vocational (VBD) and professional (PBD) ballet dancers and (b) investigate its association with body mass (BM), fat mass (FM), lean mass (LM), maturation and menarche.

METHODS

The total of 152 VBD (13 ± 2.3 years; 112 girls, 40 boys) and 96 controls (14 ± 2.1 years; 56 girls, 40 boys) and 184 PBD (28 ± 8.5 years; 129 females, 55 males) and 160 controls (27 ± 9.5 years; 110 female, 50 males) were assessed at the lumbar spine (LS), femoral neck (FN), forearm and total body by dual-energy X-ray absorptiometry. Maturation and menarche were assessed via questionnaires.

RESULTS

VBD revealed lower unadjusted BMD at all anatomical sites compared to controls (p < 0.001); following adjustments for Tanner stage and gynaecological age, female VBD showed similar BMD values at impact sites. However, no factors were found to explain the lower adjusted BMD values in VBD (female and male) at the forearm (non-impact site), nor for the lower adjusted BMD values in male VBD at the FN. Compared to controls, female PBD showed higher unadjusted and adjusted BMD for potential associated factors at the FN (impact site) (p < 0.001) and lower adjusted at the forearm (p < 0.001). Male PBD did not reveal lower BMD than controls at any site.

CONCLUSIONS

Both females and males VBD have lower BMD at impact and non-impact sites compared to control, whereas this is only the case at non-impact site in female PBD. Maturation seems to explain the lower BMD at impact sites in female VBD.

Expression and functional proteomic analyses of osteocytes from Xenopus laevis tested under mechanical stress conditions: preliminary observations on an appropriate new animal model

Hitherto, the role of the osteocyte as transducer of mechanical stimuli into biological signals is far from settled. In this study, we used an appropriate model represented by the cortex of Xenopus laevis long bone diaphysis lacking (unlike the mammalian one) of vascular structures and containing only osteocytes inside the bone matrix. These structural features allow any change of protein profile that might be observed upon different experimental conditions, such as bone adaptation to stress/mechanical loading, to be ascribed specifically to osteocytes. The study was conducted by combining ultrastructural observations and two-dimensional electrophoresis for proteomic analysis. The osteocyte population was extracted from long bones of lower limbs of amphibian skeletons after different protocols (free and forced swimming). The experiments were performed on 210 frogs subdivided into five trials, each including free swimming frogs (controls) and frogs submitted to forced swimming (stressed). The stressed groups were obliged to swim (on movable spheres covering the bottom of a pool on a vibrating plate) continuously for 8 h, and killed 24 h later along with the control groups. Long bones free of soft tissues (periosteum, endosteum and bone marrow), as well as muscles of posterior limbs, were processed and analyzed for proteins differentially expressed or phosphorylated between the two sample groups. The comparative analysis showed that protein phosphorylation profiles differ between control and stressed groups. In particular, we found in long bones of stressed samples that both Erk1/2 and Akt are hyperphosphorylated; moreover, the different phosphorylation of putative Akt substrates (recognized by specific Akt phosphosubstrates-antibody) in stressed vs. control samples clearly demonstrated that Akt signaling is boosted by forced swimming (leading to an increase of mechanical stress) of amphibian long bones. In parallel, we found in posterior limb muscles that the expression of heat shock protein HSP27 and HSP70 stress markers increased upon the forced swimming condition. Because the cortexes of frog long bones are characterized by the presence of only osteocytes, all our results establish the suitability of the X. laevis animal model to study the bone response to stress conditions mediated by this cell type and pave the way for further analysis of the signaling pathways involved in these signal transduction mechanisms.

HIGH-IMPACT DROP EXERCISE ALTERS MECHANICAL PROPERTIES IN OSTEOPENIC BONE

ABSTRACT Introduction: Osteopenia is a reversible condition and precedes osteoporosis. Physical activity and mechanical loading appear to play an important role in the regulation of bone homeostasis, without the side effects of targeted drug therapy. However, there is controversy as to which type of stimulus promotes more effective adaptations with respect to mechanical properties of bones. Objective: To investigate the effects of high-impact drop training on bone structure after ovariectomy-induced osteopenia in 40 10-week-old female Wistar rats. Methods: Twenty female rats (prevention program) were randomly assigned into two groups (n=10): Ovariectomized sedentary (OVXs), and OVX trained (OVX+Dropt). OVX+Dropt animals began training 3 days after surgery. Another twenty female rats (treatment program) were randomly assigned to two other groups (n=10): Ovariectomized sedentary (OVXs), and OVX trained (OVX+Dropt). OVX+Dropt animals began training 60 days after surgery. The rats in the trained groups were dropped from 40 cm height 20 times/day, 5 days/week over a period of 12 weeks period. At the end, the biomechanical tests were analyzed. Results: The final load and stiffness of the left tibia in the trained groups were higher than in the sedentary groups (p<0.05). Conclusions: Dropping exercise induced favorable changes in bone mechanical properties. High-impact drop exercise is effective to prevent bone loss after ovariectomy even when osteopenia is already established.

Bone mass of female dance students prior to professional dance training: A cross-sectional study

Background

Professional dancers are at risk of developing low bone mineral density (BMD). However, whether low BMD phenotypes already exist in pre-vocational dance students is relatively unknown.

Aim

To cross-sectionally assess bone mass parameters in female dance students selected for professional dance training (first year vocational dance students) in relation to aged- and sex-matched controls.

Methods

34 female selected for professional dance training (10.9yrs ±0.7) and 30 controls (11.1yrs ±0.5) were examined. Anthropometry, pubertal development (Tanner) and dietary data (3-day food diary) were recorded. BMD and bone mineral content (BMC) at forearm, femur neck (FN) and lumbar spine (LS) were assessed using Dual-Energy X-Ray Absorptiometry. Volumetric densities were estimated by calculating bone mineral apparent density (BMAD).

Results

Dancers were mainly at Tanner pubertal stage I (vs. stage IV in controls, p<0.001), and demonstrated significantly lower body weight (p<0.001) and height (p<0.01) than controls. Calorie intake was not different between groups, but calcium intake was significantly greater in dancers (p<0.05). Dancers revealed a significantly lower BMC and BMD values at all anatomical sites (p<0.001), and significantly lower BMAD values at the LS and FN (p<0.001). When adjusted for covariates (body weight, height, pubertal development and calcium intake), dance students continued to display a significantly lower BMD and BMAD at the FN (p<0.05; p<0.001) at the forearm (p<0.01).

Conclusion

Before undergoing professional dance training, first year vocational dance students demonstrated inferior bone mass compared to controls. Longitudinal models are required to assess how bone health-status changes with time throughout professional training.

The effects of different intensities of exercise and active vitamin D on mouse bone mass and bone strength

Physical exercise is beneficial to bone health. However, little is known how different intensities of exercise affect bone mass and strength. In the present study, we used young mice to study the effects of different intensities of exercise on bone mass and bone strength in comparison to pharmacological doses of active vitamin D (calcitriol). We found that only the medium level of exercise tested showed a positive effect on bone mineral density, trabecular bone volume, and bone strength, which are attributable to a decrease in bone resorption and an increase in bone formation, with the latter being accompanied by an increase in the number of osteogenic mesenchymal stem cells in the bone marrow. Calcitriol increases bone volume and bone strength, yet the combination of calcitriol and medium-intensity exercise did not further improve bone mass or strength. Moreover, calcitriol also showed some protective effect on the bone in mice with high levels of exercise. These results indicate that exercise at medium intensity increases bone mass and strength via affecting both bone formation and resorption and that its beneficial effects on bone mass cannot be further improved by calcitriol.

Swimming and peak bone mineral density: A systematic review and meta-analysis

This meta-analysis aims to determine the effects of regular swimming on bone mineral density (BMD) in young adults (18-30 years). A systematic search was performed in Pubmed, SPORTDiscus and the Cochrane Library from the earliest possible year to March 2016. Swimmers were compared to non-athletic controls (CG) and to high-impact athletes (HIGH). Effect sizes with the Hedges g in random effects models were developed. Fourteen studies met the inclusion criteria and were included in the meta-analyses. Swimmers presented similar BMD values to CG in whole-body (g = -0.20; P = 0.251), femoral neck (g = -0.05; P = 0.818) and lumbar spine (g = 0.18; P = 0.492); and lower BMD in the whole-body (g = -1.21; P < 0.001), femoral neck (g = -1.51; P < 0.001) and lumbar spine (g = -0.84; P = 0.017) than the HIGH. For the whole-body differences, the higher the latitude the smaller the differences between swimmers and HIGH (B = 0.10; P = 0.001). For the femoral neck differences, age also seemed to reduce the differences between groups (B = 0.19; P = 0.020). Young adult swimmers present similar BMD values than CG and lower values than HIGH.

Jumping exercise preserves bone mineral density and mechanical properties in osteopenic ovariectomized rats even following established osteopenia

The effects of jump training on bone structure before and after ovariectomy-induced osteopenia in rats were investigated. Jumping exercise induced favorable changes in bone mineral density, bone mechanical properties, and bone formation/resorption markers. This exercise is effective to prevent bone loss after ovariectomy even when osteopenia is already established.

INTRODUCTION

The present study investigated the effects of jump training on bone structure before and after ovariectomy-induced osteopenia in 80 10-week-old Wistar rats.

METHODS

Forty rats (prevention program) were randomly allocated to one of four equal groups (n = 10): sham-operated sedentary (SHAM-SEDp), ovariectomized (OVX) sedentary (OVX-SEDp), sham-operated exercised (SHAM-EXp), and OVX exercised (OVX-EXp). SHAM-EXp and OVX-EXp animals began training 3 days after surgery. Another 40 rats (treatment program) were randomly allocated into another four groups (n = 10): sham-operated sedentary (SHAM-SEDt), OVX sedentary (OVX-SEDt), sham-operated exercised (SHAM-EXt), and OVX exercised (OVX-EXt). SHAM-EXt and OVX-EXt animals began training 60 days after surgery. The rats in the exercised groups jumped 20 times/day, 5 days/week, to a height of 40 cm for 12 weeks. At the end of the experimental period, serum osteocalcin, follicle-stimulating hormone (FSH) dosage, dual X-ray absorptiometry (DXA), histomorphometry, and biomechanical tests were analyzed.

RESULTS

The OVX groups showed higher values of FSH and body weight (p < 0.05). DXA showed that jump training significantly increased bone mineral density of the femur and fifth lumbar vertebra (p < 0.05). The stiffness of the left femur and fifth lumbar vertebra in the exercised groups was greater than that of the sedentary groups (p < 0.05). Ovariectomy induced significant difference in bone volume (BV/TV, percent), trabecular separation (Tb.Sp, micrometer), and trabecular number (Tb.N, per millimeter) (p < 0.05) compared to sham operation. Jump training in the OVX group induced significant differences in BV/TV, Tb.Sp, and Tb.N and decreased osteoblast number per bone perimeter (p < 0.05) compared with OVX nontraining, in the prevention groups. Osteocalcin dosage showed higher values in the exercised groups (p < 0.05).

CONCLUSIONS

Jumping exercise induced favorable changes in bone mineral density, bone mechanical properties, and bone formation/resorption markers. Jump training is effective to prevent bone loss after ovariectomy even when osteopenia is already established.

Femoral Neck Strain during Maximal Contraction of Isolated Hip-Spanning Muscle Groups

The aim of the study was to investigate femoral neck strain during maximal isometric contraction of the hip-spanning muscles. The musculoskeletal and the femur finite-element models from an elderly white woman were taken from earlier studies. The hip-spanning muscles were grouped by function in six hip-spanning muscle groups. The peak hip and knee moments in the model were matched to corresponding published measurements of the hip and knee moments during maximal isometric exercises about the hip and the knee in elderly participants. The femoral neck strain was calculated using full activation of the agonist muscles at fourteen physiological joint angles. The 5% ± 0.8% of the femoral neck volume exceeded the 90th percentile of the strain distribution across the 84 studied scenarios. Hip extensors, flexors, and abductors generated the highest tension in the proximal neck (2727 με), tension (986 με) and compression (-2818 με) in the anterior and posterior neck, and compression (-2069 με) in the distal neck, respectively. Hip extensors and flexors generated the highest neck strain per unit of joint moment (63-67 με·m·N-1) at extreme hip angles. Therefore, femoral neck strain is heterogeneous and muscle contraction and posture dependent.

The Femoral Neck Mechanoresponse to Hip Extensors Exercise: A Case Study

Physical activity is recommended to prevent age-related bone loss. However, the proximal femur mechanoresponse is variable, possibly because of a muscle-dependant mechanoresponse. We compared the proximal femur response with the femoral strain pattern generated by the hip extensor muscles. A healthy participant underwent a six-month unilateral training of the hip extensor muscles using a resistance weight regularly adjusted to the 80% of the one-repetition maximum weight. DXA-based measurements of the areal Bone Mineral Density (aBMD) in the exercise leg were adjusted for changes in the control leg. The biomechanical stimulus for bone adaptation (BS) was calculated using published models of the musculoskeletal system and the average hip extension moment in elderly participants. Volumetric (ΔvBMD) and areal (ΔaBMD) BMD changes were calculated. The measured and calculated BMD changes consistently showed a positive and negative effect of exercise in the femoral neck (ΔaBMD = +0.7%; ΔvBMD = +0.8%) and the trochanter region (ΔaBMD = -4.1%; ΔvBMD = -0.5%), respectively. The 17% of the femoral neck exceeded the 75th percentile of the spatially heterogeneous BS distribution. Hip extensor exercises may be beneficial in the proximal femoral neck but not in the trochanteric region. DXA-based measurements may not capture significant aBMD local changes.

Preconception endurance training with voluntary exercise during pregnancy positively influences on remodeling markers in female offspring bone

OBJECTIVE

In this study, we investigate the effects of preconception endurance training with or without voluntary exercise during pregnancy on indices of bone formation and resorption in female offspring bone.

METHODS

Twenty-four C57BL/6 female mice were randomly divided into four groups: trained in preconception period and exercised during pregnancy (TE); trained in preconception periods but unexercised during pregnancy (TC); untrained in preconception periods but exercised during pregnancy (CE); untrained and unexercised (CC). Trained dams were subjected to a protocol of moderate exercise training over a period of 4 weeks before pregnancy. Analyses were performed on the adult female offspring that did not have access to running wheels in any portion of their lives.

RESULTS

The OPG, Runx2, COLI, ALP, and OPN mRNA expression was significantly up-regulated in offspring born to dams that was trained in preconception period. However, there was no significant difference in OPG, COLI, Runx2, and ALP expression in TE and TC offspring (p > 0.05). RANKL and osteocalcin expression were significantly down-regulated in TE offspring group (p < 0.001).

CONCLUSIONS

Improved physical fitness in preconception period results in significant changes in bone gene expressions of female offspring, in particular towards osteogenic responses with improved RANKL/OPG ratio.

The effects of exercise training and type of exercise training on changes in bone mineral denstiy in Korean postmenopausal women: a systematic review

[Purpose]

To systematically review the effects of exercise training and the type of exercise training on changes in bone mineral density (BMD) in Korean postmenopausal women.

[Methods]

Korean studies Information Service System (KISS) and PubMed were searched and 17 randomized control trials were selected. Changes in BMD of lumbar spine (LS), femur neck (FN), Ward’s triangle (WT), and trochanter (Tro) were chosen as major outcomes.

[Results]

Exercise training increased BMD of LS, FN, WT, and Tro. According to the type of exercise training, combined exercise training (aerobic + resistance) showed improvements in BMD of LS, FN, WT, and Tro. However, aerobic exercise training alone and resistance exercise training alone showed inconsistent results.

[Conclusion]

Exercise training can improve the BMD of LS, FN, WT, and Tro in Korean postmenopausal women. The type of exercise training may be a crucial factor for maintaining or improving bone health of this population.

Bone mineral density is reduced by telmisartan in male spontaneously hypertensive rats

BACKGROUND

Telmisartan, an angiotensin AT1 receptor blocker, and treadmill running were compared for their effects on bone mineral density (BMD) and biomechanical properties of male spontaneously hypertensive rats (SHR). It was hypothesized that running (18m/min/60min/d) and telmisartan (5mg/kg/d) would have a positive effect on bone parameters.

METHODS

Three-month-old male SHRs were divided into three groups: sedentary (S), telmisartan (T), and exercise (E). At the end of an 8-week protocol, femur and lumbar vertebrae were analyzed by dual-energy X-ray absorptiometry (DXA) for bone mineral density and by the three-point bending test for biomechanical properties. Blood pressure in all groups was measured by a tail-cuff manometer.

RESULTS

Telmisartan and treadmill running reduced blood pressure when compared to the sedentary group; however, telmisartan did not improve bone characteristics. Instead, it reduced BMD of femur total and lumbar vertebrae and worsened bone biomechanic properties. Treadmill running maintained bone characteristics and hence was effective in maintaining bone health.

CONCLUSION

Results showed that telmisartan negatively affected bones suggesting that caution should be taken in possible therapeutic applications for protecting bone health in hypertensive conditions. More studies are necessary to clarify the mechanisms through which telmisartan favors bone loss in this model.

Prolonged Practice of Swimming Is Negatively Related to Bone Mineral Density Gains in Adolescents

BACKGROUND

The practice of swimming in "hypogravity" conditions has potential to decrease bone formation because it decreases the time engaged in weight-bearing activities usually observed in the daily activities of adolescents. Therefore, adolescents competing in national levels would be more exposed to these deleterious effects, because they are engaged in long routines of training during most part of the year. To analyze the effect of swimming on bone mineral density (BMD) gain among adolescents engaged in national level competitions during a 9-month period.

METHODS

Fifty-five adolescents; the control group contained 29 adolescents and the swimming group was composed of 26 athletes. During the cohort study, BMD, body fat (BF) and fat free mass (FFM) were assessed using a dual-energy x-ray absorptiometry scanner. Body weight was measured with an electronic scale, and height was assessed using a stadiometer.

RESULTS

During the follow-up, swimmers presented higher gains in FFM (Control 2.35 kg vs. Swimming 5.14 kg; large effect size [eta-squared (ES-r)=0.168]) and BMD-Spine (Swimming 0.087 g/cm(2) vs. Control 0.049 g/cm(2); large effect size [ES-r=0.167]) compared to control group. Male swimmers gained more FFM (Male 10.63% vs. Female 3.39%) and BMD-Spine (Male 8.47% vs. Female 4.32%) than females. Longer participation in swimming negatively affected gains in upper limbs among males (r=-0.438 [-0.693 to -0.085]), and in spine among females (r=-0.651 [-0.908 to -0.036]).

CONCLUSIONS

Over a 9-month follow-up, BMD and FFM gains were more evident in male swimmers, while longer engagement in swimming negatively affected BMD gains, independently of sex.

Efficacy of a workplace osteoporosis prevention intervention: a cluster randomized trial

BACKGROUND

Osteoporosis is a debilitating disease. Adequate calcium consumption and physical activity are the two major modifiable risk factors. This paper describes the major outcomes and efficacy of a workplace-based targeted behaviour change intervention to improve the dietary and physical activity behaviours of working women in sedentary occupations in Singapore.

METHODS

A cluster-randomized design was used, comparing the efficacy of a tailored intervention to standard care. Workplaces were the units of randomization and intervention. Sixteen workplaces were recruited from a pool of 97, and randomly assigned to intervention and control arms (eight workplaces in each). Women meeting specified inclusion criteria were then recruited to participate. Workplaces in the intervention arm received three participatory workshops and organization-wide educational activities. Workplaces in the control/standard care arm received print resources. Outcome measures were calcium intake (milligrams/day) and physical activity level (duration: minutes/week), measured at baseline, 4 weeks and 6 months post intervention. Adjusted cluster-level analyses were conducted comparing changes in intervention versus control groups, following intention-to-treat principles and CONSORT guidelines.

RESULTS

Workplaces in the intervention group reported a significantly greater increase in calcium intake and duration of load-bearing moderate to vigorous physical activity (MVPA) compared with the standard care control group. Four weeks after intervention, the difference in adjusted mean calcium intake was 343.2 mg/day (95 % CI = 337.4 to 349.0, p < .0005) and the difference in adjusted mean load-bearing MVPA was 55.6 min/week (95 % CI = 54.5 to 56.6, p < .0005). Six months post intervention, the mean differences attenuated slightly to 290.5 mg/day (95 % CI = 285.3 to 295.7, p < .0005) and 50.9 min/week (95 % CI =49.3 to 52.6, p < .0005) respectively.

CONCLUSION

This workplace-based intervention substantially improved calcium intake and load-bearing moderate to vigorous physical activity 6 months after the intervention began.

TRIAL REGISTRATION

Australia New Zealand Clinical Trial Registry ACTRN12616000079448 . Registered 25 January 2016 (retrospectively registered).

Bone repair: Effects of physical exercise and LPS systemic exposition

Bone repair can be facilitated by grafting, biochemical and physical stimulation. Conversely, it may be delayed lipopolysaccharide (LPS). Physical exercise exerts beneficial effects on the bone, but its effect on bone repair is not known. We investigated the effect of exercise on the LPS action on bone healing through bone densitometry, quantitative histological analysis for bone formation rate and immunohistochemical markers in sedentary and exercised animals. Rats ran on the treadmill for four weeks. After training the rats were submitted to a surgical procedure (bone defect in the right tibia) and 24h after the surgery LPS was administered at a dose of 100μg/kg i.p., whereas the control rats received a saline injection (1ml/kg, i.p.). Right tibias were obtained for analysis after 10days during which rats were not submitted to physical training. Physical exercise had a positive effect on bone repair, increasing bone mineral density, bone mineral content, bone formation rate, type I collagen and osteocalcin expression. These parameters were not affected by systemic administration of LPS. Our data indicate that physical exercise has an important osteogenic effect, which is maintained during acute systemic inflammation induced by exposure to a single dose of LPS.

Physical activity preferences of individuals diagnosed with schizophrenia or bipolar disorder

Background

Individuals with a severe mental illness (SMI) are at least two times more likely to suffer from metabolic co-morbidities, leading to excessive and premature deaths. In spite of the many physical and mental health benefits of physical activity (PA), individuals with SMI are less physically active and more sedentary than the general population. One key component towards increasing the acceptability, adoption, and long-term adherence to PA is to understand, tailor and incorporate the PA preferences of individuals. Therefore, the objective of this study was to determine if there are differences in PA preferences among individuals diagnosed with different psychiatric disorders, in particular schizophrenia or bipolar disorder (BD), and to identify PA design features that participants would prefer.

Methods

Participants with schizophrenia (n = 113) or BD (n = 60) completed a survey assessing their PA preferences.

Results

There were no statistical between-group differences on any preferred PA program design feature between those diagnosed with schizophrenia or BD. As such, participants with either diagnosis were collapsed into one group in order to report PA preferences. Walking (59.5 %) at moderate intensity (61.3 %) was the most popular activity and participants were receptive to using self-monitoring tools (59.0 %). Participants were also interested in incorporating strength and resistance training (58.5 %) into their PA program and preferred some level of regular contact with a fitness specialist (66.0 %).

Conclusions

These findings can be used to tailor a physical activity intervention for adults with schizophrenia or BD. Since participants with schizophrenia or BD do not differ in PA program preferences, the preferred features may have broad applicability for individuals with any SMI.

Direct effects of physical training on markers of bone metabolism and serum sclerostin concentrations in older adults with low bone mass

Background

Both gravitational loading and the forces generated by muscle contraction have direct effects on serum markers of bone metabolism. The object of this study was to examine the direct effects of a single session of resistance exercise or walking on biochemical markers of bone metabolism in participants with low bone mass.

Methods

A total of 150 otherwise healthy female subjects (mean age = 59.1 ± 7.1 years) diagnosed with osteoporosis or osteopenia were randomly allocated to either a resistance exercise group (RG; n = 50), walking group (WG; n = 50), or control group (CG; n = 50). Changes in bone-specific alkaline phosphatase (BALP), carboxy-terminal cross-linked telopeptide of type I collagen (CTX), and serum sclerostin concentrations were measured before and immediately after a single exercise intervention.

Results

There was no significant change in BALP values in any of the groups. Sclerostin levels increased in the RG and WG, and there was significant difference between the WG and CG after the exercise intervention (P < 0.01). In contrast, the changes in CTX concentrations from baseline were significant in the RG (P < 0.01) but not in the WG (P = 0.11), and there was a significant difference between resistance exercise and walking (P < 0.01).

Conclusions

In participants with low bone mass, resistance exercise influenced the serum concentrations of CTX, a marker of bone resorption, but walking did not.

Trial registration

Current Controlled Trials ISRCTN16329455; retrospectively registered on 05/05/2016.

Bone health and HIV in resource-limited settings: a scoping review

PURPOSE OF REVIEW

Sub-Saharan Africa and other resource-limited settings (RLS) bear the greatest burden of the HIV epidemic globally. Advantageously, the expanding access to antiretroviral therapy (ART) has resulted in increased survival of HIV individuals in the last 2 decades. Data from resource rich settings provide evidence of increased risk of comorbid conditions such as osteoporosis and fragility fractures among HIV-infected populations. We provide the first review of published and presented data synthesizing the current state of knowledge on bone health and HIV in RLS.

RECENT FINDINGS

With few exceptions, we found a high prevalence of low bone mineral density (BMD) and hypovitaminosis D among HIV-infected populations in both RLS and resource rich settings. Although most recognized risk factors for bone loss are similar across settings, in certain RLS there is a high prevalence of both non-HIV-specific risk factors and HIV-specific risk factors, including advanced HIV disease and widespread use of ART, including tenofovir disoproxil fumarate, a non-BMD sparing ART. Of great concern, we neither found published data on the effect of tenofovir disoproxil fumarate initiation on BMD, nor any data on incidence and prevalence of fractures among HIV-infected populations in RLS.

SUMMARY

To date, the prevalence and squeal of metabolic bone diseases in RLS are poorly described. This review highlights important gaps in our knowledge about HIV-associated bone health comorbidities in RLS. This creates an urgent need for targeted research that can inform HIV care and management guidelines in RLS.

Swimming and bone: Is low bone mass due to hypogravity alone or does other physical activity influence it?

Swimming during adolescence has shown neutral or even negative effects on bone mass. Nevertheless, it is still unknown if these effects are due to swimming or to other factors, such as sedentary behaviors.

INTRODUCTION

Three objectives were described (1) to measure objective physical activity (PA) additional to swimming performed by adolescent swimmers (SWI) and compare it to that performed by normo-active controls (CG), (2) to describe the relationship between objectively measured PA and bone mass, and (3) to compare bone mass of swimmers that meet the World Health Organization PA guidelines (active) WHO and those that do not (inactive).

METHODS

A total of 71 SWI (33 females) and 41 CG (17 females) wore an accelerometer for at least 4 days. PA was expressed as the amount of time (minutes/day) in each intensity [sedentary/light/moderate or vigorous (VPA), and the sum of moderate and vigorous (MVPA)]. Using the cutoff points proposed by Vanhelst et al. SWI were classified as active or inactive according to whether they reached 60 min of weight-bearing MVPA per day or not. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry, and bone strength values were calculated with peripheral quantitative computed tomography. Differences in PA intensities were calculated between SWI and CG. The relation of VPA to bone mass was studied in the SWI.

RESULTS

Male-SWI spend less time in VPA and MVPA than male-GC, which partly explains the lower BMD values in SWI than CG.

CONCLUSION

Swimming may displace weight-bearing VPA with serious implications on bone health.

Long-Term Examination of Bone Mineral Density in the Calcanei After Anterior Cruciate Ligament Reconstruction in Adolescents and Matched Adult Controls

PURPOSE

The aims were to evaluate the results 10 to 20 years after anterior cruciate ligament (ACL) reconstruction performed in adolescents in terms of bone mineral density (BMD) in the calcanei using the dual-energy x-ray absorptiometry (DXA) technique, activity level, and quality of life.

METHODS

A case-control study of adolescents who underwent ACL reconstruction between 1992 and 2002 was performed. The inclusion criterion was a unilateral ACL injury. The exclusion criteria were bilateral ACL injury, contralateral ACL reconstruction, posterior cruciate ligament injury, and previous or present fractures of either lower extremity. The BMD was measured in both calcanei using the DXA technique and compared with a control group of adult ACL-reconstructed patients and with a DXA reference database. The age of the control group was similar to that of the patient group at the time of BMD assessment, performed 60 months after reconstruction. Activity was measured with the Tegner activity scale. The EQ-5D was used to evaluate quality of life.

RESULTS

Thirty-two adolescents (11 boys and 21 girls), aged 12 to 16 years, with a symptomatic unilateral ACL rupture, underwent reconstruction at near skeletally mature age. Of these patients, 29 (91%) took part in the follow-up examination. The BMD values for the male patients were lower on the injured and non-injured sides (-15.2% [P = .02] and -11.8% [P = .05], respectively) compared with the control group. The values for the female patients were -0.8% (P = .84) and -2.2% (P = .69), respectively. Correspondingly, the BMD values for the male patients were lower on the injured and non-injured sides (-8.2% and -4.9%, respectively) compared with the male reference database. The BMD values for the female patients were higher on the injured and non-injured sides (4.1% and 4.3%, respectively) compared with the female reference database. In the control group, female patients had a significantly lower value for the Tegner activity scale preoperatively (median, 2.0; range, 0 to 5) than the female patients in the study group (median, 3.0; range, 2 to 8) (P = .006). In the study group, the Tegner activity scale at follow-up showed a significant correlation with the BMD on the injured side for male patients (ρ = 0.67, P = .03) but not on the non-injured side (ρ = 0.50, P = .14). In the control group, the Tegner activity scale at follow-up showed a significant correlation with the BMD on the non-injured side for female patients (ρ = 0.61, P = .03) but not on the injured side (ρ = 0.34, P = .25). The Tegner activity scale and EQ-5D showed no significant differences between the study groups.

CONCLUSIONS

In the long-term, the BMD in the calcanei of patients who were adolescents at the time of ACL reconstruction differed from that of a control group and a reference database. This study indicates that boys with an ACL injury and subsequent ACL reconstruction run a subsequent risk of a significantly lower BMD in their calcanei as adults and, consequently, an increased future fracture risk.

LEVEL OF EVIDENCE

Level III, case-control study.

Effects of Vitamin D3 Supplementation on Lean Mass, Muscle Strength, and Bone Mineral Density During Weight Loss: A Double-Blind Randomized Controlled Trial

OBJECTIVES

To compare the effects of 12 months of vitamin D3 supplementation with that placebo on lean mass, bone mineral density (BMD), and muscle strength in overweight or obese postmenopausal women completing a structured weight-loss program.

DESIGN

Double-blind, placebo-controlled randomized clinical trial.

SETTING

Fred Hutchinson Cancer Research Center, Seattle, Washington.

PARTICIPANTS

Postmenopausal women aged 50 to 75 with a body mass index (BMI) of 25 kg/m(2) or greater and a serum 25-hydroxyvitamin D (25(OH)D) concentration between 10.0 and 32.0 ng/mL (insufficient) (N = 218).

INTERVENTION

Oral vitamin D3 2,000 IU/d or placebo in combination with a lifestyle-based weight loss intervention consisting of a reduction of 500 kcal to 1,000 kcal per day and 225 min/wk of moderate- to vigorous-intensity aerobic exercise.

MEASUREMENTS

Serum 25(OH)D, body composition, and muscle strength were measured before randomization (baseline) and at 12 months. Mean changes of the groups were compared (intention to treat) using generalized estimating equations.

RESULTS

Change in 25(OH)D was significantly different between the vitamin D and placebo groups at 12 months (13.6 ng/mL vs -1.3 ng/mL, P < .001), but no differences in change in lean mass (-0.8 kg vs -1.1 kg, P = .53) or BMD of the spine (-0.01 g/cm(2) vs 0.0 g/cm(2) , P = .82) or right femoral neck (both -0.01 g/cm(2) , P = .49) were detected between the groups. Leg strength decreased in the vitamin D group but not in the placebo group (-2.6 pounds vs 1.8 pounds, P = .03). In women randomized to vitamin D, achieving repletion (25(OH)D ≥ 32 ng/mL) did not alter results.

CONCLUSION

Vitamin D3 supplementation during weight-loss decreased leg strength but did not alter changes in lean mass or BMD in postmenopausal women with vitamin D insufficiency.

Swimming and cycling do not cause positive effects on bone mineral density: a systematic review

Osteoporosis is considered a common metabolic bone disease and its prevalence is increasing worldwide. In this context, physical activity has been used as a non-pharmacological tool for prevention and auxiliary treatment of this disease. The aim of this systematic review was to evaluate the effects of cycling and swimming practice on bone mineral density (BMD). This research was conducted in accordance with the recommendations outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The studies were consulted in the period from 2004 to 2014, through major electronic databases: PubMed(®), SciELO(®) and LILACS(®). Ten studies evaluated the effects of cycling on BMD, and the results showed that nine studies have linked the practice of professional cycling with low levels of BMD. Another 18 studies have reported that swimming has no positive effects on bone mass. We conclude that cycling and swimming do not cause positive effects on BMD; thus, these are not the most suitable exercises for prevention and treatment of osteoporosis.

Response of Bone Turnover Markers and Cytokines to High-Intensity Low-Impact Exercise

INTRODUCTION

Low-impact, high-intensity interval exercise (HIE) was used to investigate the postexercise response in bone turnover markers and cytokines.

METHODS

Twenty-three recreationally active males (21.8 ± 2.4 yr) performed one HIE bout on a cycle ergometer at 90% maximum workload. The total duration of the exercise was 12 min and included six 1-min high-intensity exercise intervals separated by 1-min rest intervals. Blood samples were collected before exercise, 5 min, 1 h, and 24 h after exercise and were analyzed for serum levels of anti- and pro-inflammatory cytokines (interleukin 10 [IL-10], interleukin 6 [IL-6], interleukin 1-alpha [IL-1α], interleukin 1-beta [IL-1β], and tumor necrosis factor alpha [TNF-α]) and markers of bone formation (bone alkaline phosphatase [BAP], osteoprotegerin [OPG]) and resorption (amino-terminal cross-linking propeptide [NTX], receptor activator of NF-κB ligand [RANKL]).

RESULTS

There was a significant (P < 0.05) time effect for all bone turnover markers. Post hoc analysis showed that BAP, OPG, and RANKL significantly increased from baseline to 5 min after exercise (10.9%, 13.5%, and 34.2%, P < 0.05). At 1 h after exercise, only BAP was significantly higher than baseline (9.5%, P = 0.010) and remained higher than baseline at 24 h (10.9%, P = 0.001). NTX was significantly lower than baseline 24 h after exercise (-14.6%, P = 0.046). Significant (P < 0.05) time effects were also observed for IL-1α, IL-1β, IL-6, and TNF-α, with all four significantly increasing 5 min after exercise and returning to baseline levels 1 h after exercise. The postexercise changes in bone formation markers correlated positively with the anti-inflammatory cytokine (IL-10) and negatively with the pro-inflammatory cytokines while NTX correlated positively with a pro-inflammatory cytokine, TNF-α (P < 0.05).

CONCLUSIONS

These results suggest that HIE stimulates a response in bone turnover markers and cytokines and that a correlation exists between immune and skeletal responses to this form of exercise. This type of exercise may benefit individuals for whom high-impact exercise might be contraindicated.

Reduced bone resorption and increased bone mineral density in women with restless legs syndrome

OBJECTIVE

To investigate bone resorption and formation markers as well as bone mineral density in women with restless legs syndrome (RLS).

METHODS

This was a prospective cross-sectional case-control study involving drug-naive women with RLS and age- and body mass index (BMI)-matched female controls. Routine blood analyses, markers of bone formation, procollagen 1 n-terminal peptide, bone resorption, c-telopeptide of type 1 collagen (CTX), sclerostin, and bone mineral density (BMD) were compared between the 2 groups. Pregnant or breastfeeding women and individuals with comorbidities other than iron deficiency, type 2 diabetes mellitus, or hypertension were excluded.

RESULTS

A significant increase in lumbar BMD was found among 78 women with RLS as compared to 78 age- and BMI-matched controls (p = 0.001). The proportion of patients with osteopenia as defined by a lumbar T score was significantly lower among patients with RLS (p = 0.040). CTX and sclerostin were significantly lower in patients with RLS (p = 0.006 and p = 0.011, respectively), as were the levels of 25-hydroxy vitamin D3, calcemia, and free T3 (p = 0.017, p = 0.017, and p = 0.002, respectively).

CONCLUSIONS

Despite lower 25-hydroxy vitamin D3, patients with RLS had lower bone resorption markers, higher lumbar BMD, and lower frequency of lumbar osteopenia. As patients with RLS make movements night and day to decrease the severity of their symptoms, they unconsciously perform exercise, which may potentially explain the better bone profile among patients with RLS than in controls.

Swimming and cycling do not cause positive effects on bone mineral density: a systematic review

Osteoporosis is considered a common metabolic bone disease and its prevalence is increasing worldwide. In this context, physical activity has been used as a non-pharmacological tool for prevention and auxiliary treatment of this disease. The aim of this systematic review was to evaluate the effects of cycling and swimming practice on bone mineral density (BMD). This research was conducted in accordance with the recommendations outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The studies were consulted in the period from 2004 to 2014, through major electronic databases: PubMed®, SciELO® and LILACS®. Ten studies evaluated the effects of cycling on BMD, and the results showed that nine studies have linked the practice of professional cycling with low levels of BMD. Another 18 studies have reported that swimming has no positive effects on bone mass. We conclude that cycling and swimming do not cause positive effects on BMD; thus, these are not the most suitable exercises for prevention and treatment of osteoporosis.

Recreational football for disease prevention and treatment in untrained men: a narrative review examining cardiovascular health, lipid profile, body composition, muscle strength and functional capacity

Over the past 10 years, researchers have studied the effects of recreational football training as a health-promoting activity for participants across the lifespan. This has important public health implications as over 400 million people play football annually. Results from the first randomised controlled trial, published in the BJSM in January 2009, showed that football increased maximal oxygen uptake and muscle and bone mass, and lowered fat percentage and blood pressure, in untrained men, and since then more than 70 articles about football for health have been published, including publications in two supplements of the Scandinavian Journal of Medicine and Science in Sports in 2010 and 2014, prior to the FIFA World Cup tournaments in South Africa and Brazil. While studies of football training effects have also been performed in women and children, this article reviews the current evidence linking recreational football training with favourable effects in the prevention and treatment of disease in adult men.

Long-Term Exercise and Bone Mineral Density Changes in Postmenopausal Women--Are There Periods of Reduced Effectiveness?

There is increasing evidence that physical exercise can prevent fractures in postmenopausal women. However, even with careful adaptation of the exercise program to subjects' changing bone, health, and fitness status, effectivity may still decrease over the time. This could be specifically the case where the limitations of higher age collide with the specification of the exercise program. Thus, the aim of this study was to monitor bone mineral density (BMD) changes over a 16-year period of supervised exercise. Our hypothesis was that BMD differences at lumbar spine (LS) and femoral neck (FN) between exercisers (EG) and nontraining controls (CG) increased throughout the intervention with significant differences for each of the four 4-year observation periods. Sixty-seven (EG, n = 39 versus CG, n = 28) initially early-postmenopausal osteopenic women of the Erlangen Fitness and Osteoporosis Prevention Study (EFOPS) with complete BMD data sets for baseline (1998) and 4-, 8-, 12-, and 16-year follow-up were included in the analysis. The exercise protocol initially focused on a high-intensity strategy that addressed bone but increasingly shifted to a more comprehensive intervention. LS-BMD differences between the EG and CG continuously increased (year 4: 2.4% (95%- Confidence Interval 1.0% to 3.8%), year 8: 3.1% (1.6% to 4.7%), year 12: 3.9% (1.9% to 5.8), year 16: 4.5% (2.5% to 6.6%). Correspondingly, rising differences for FN-BMD (0.9% (-0.2% to 2.1%) versus 1.9% (0.4% to 3.3%) versus 2.0% (0.5% to 3.8%) versus 3.0% (1.0% to 5.0%)) were observed. However, in contrast to our hypothesis, group differences within the four 4-year periods were not consistently significant (LS, p = 0.001 to 0.097; FN, p = 0.026 to 0.673); further, BMD kinetics among the groups varied between LS and FN. Of particular importance, significant differences (p ≤ 0.030) for both regions were still found in the final period. We conclude that exercise-even when adapted for subjects' decreasing bone, health, and fitness status-is consistently effective in favorably affecting BMD in (initially) early-postmenopausal osteopenic women without any leveling-off effect after 16 years of exercise.

The Effect of Long-Term Exercise on the Production of Osteoclastogenic and Antiosteoclastogenic Cytokines by Peripheral Blood Mononuclear Cells and on Serum Markers of Bone Metabolism

Although it is recognized that the mechanical stresses associated with physical activity augment bone mineral density and improve bone quality, our understanding of how exercise modulates bone homeostasis at the molecular level is lacking. In a before and after trial involving 43 healthy adults, we measured the effect of six months of supervised exercise training on the spontaneous and phytohemagglutinin-induced production of osteoclastogenic cytokines (interleukin-1α, tumor necrosis factor-α), antiosteoclastogenic cytokines (transforming growth factor-β1 and interleukins 4 and 10), pleiotropic cytokines with variable effects on osteoclastogenesis (interferon-γ, interleukin-6), and T cell growth and differentiation factors (interleukins 2 and 12) by peripheral blood mononuclear cells. We also measured lymphocyte phenotypes and serum markers of bone formation (osteocalcin), bone resorption (C-terminal telopeptides of Type I collagen), and bone homeostasis (25 (OH) vitamin D, estradiol, testosterone, parathyroid hormone, and insulin-like growth factor 1). A combination of aerobic, resistance, and flexibility exercises done on average of 2.5 hours a week attenuated the production of osteoclastogenic cytokines and enhanced the production of antiosteoclastogenic cytokines. These changes were accompanied by a 16% reduction in collagen degradation products and a 9.8% increase in osteocalcin levels. We conclude that long-term moderate intensity exercise exerts a favorable effect on bone resorption by changing the balance between blood mononuclear cells producing osteoclastogenic cytokines and those producing antiosteoclastogenic cytokines. This trial is registered with Clinical Trials.gov Identifier: NCT02765945.

Relationship between Bone Mineral Density and Spinal Muscle Area in Magnetic Resonance Imaging

Background

Bone mineral density (BMD) is known to have a positive correlation with lean body mass. Several studies have also reported the positive correlation between muscle power and BMD. From this point of view, we hypothesized BMD of lumbar spine to have a positive correlation with muscle mass.

Methods

Seventy-nine female patients aged between 60 and 75 years old and who underwent magnetic resonance imaging (MRI) and BMD studies were included. Muscle mass in spine MRI was defined by the sum of the average muscle area of three axial images for each disc level. Lumbosacral muscle is the sum of paraspinal muscle and psoas muscle.

Results

In correlation analysis, paraspinal muscle mass showed positive correlation with BMD of lumbar spine. Lumbosacral muscle mass showed positive correlation with BMD of trochanteric area of the femur. However, BMD of other area showed no significant correlation with muscle mass.

Conclusions

Therefore, postmenopausal women older than 60 years with a well developed spine muscle mass, have a high BMD.

Effect of exercises with weight vests and a patient education programme for women with osteopenia and a healed wrist fracture: a randomized, controlled trial of the OsteoACTIVE programme

Background

Exercise programmes have shown to be important for the prevention of fractures in patients with established osteoporosis. However, few studies have evaluated the effect of such programmes for women with low bone mineral density (BMD) (osteoporosis or osteopenia) who have already suffered a fracture. Studies have indicated that exercise programmes concentrating on muscular strength and dynamic balance have a positive effect on significant risk factors for falls such as quadriceps strength and balance. The aim of the present study was to assess the effect of a 6-month exercise programme and a patient education component (OsteoACTIVE) on quadriceps strength, BMD, dynamic balance, walking capacity, physical activity level and quality of life in postmenopausal women with osteopenia and a previous wrist fracture.

Methods

Eighty postmenopausal women with low BMD and a healed wrist fracture were randomized to OsteoACTIVE (n = 42) (age 65.5, range 51.2–79.2 years) or patient education only (control group) (n = 38) (age 63.9, range 52.7–86.8 years). Follow-up was conducted after 6 months (end of intervention) and 1 year. Outcome measures included quadriceps strength, BMD, dynamic balance, walking capacity, physical activity level and quality of life.

Results

Thirty-five participants (83 %) completed the OsteoACTIVE programme. Mean adherence to OsteoACTIVE was 87 % (range 48–100 %). Twenty-five participants (72 %) met the a priori goal of 80 % adherence to the program. No adverse events were reported. There were no significant differences between the two groups over the 1-year follow-up for any of the outcome measures.

Conclusion

The OsteoACTIVE rehabilitation programme revealed no significant effect on quadriceps strength, BMD, dynamic balance, walking capacity or self-reported functional outcomes over the 1-year follow-up.

Trial registration

NCT01357278 at ClinicalTrials.gov (date of registration2010-04-21).

Effects of Tai Chi and Walking Exercises on Weight Loss, Metabolic Syndrome Parameters, and Bone Mineral Density: A Cluster Randomized Controlled Trial

Tai Chi and walking are both moderate-intensity physical activity (PA) that can be easily practiced in daily life. The objective of the study was to determine the effects of these two PAs on weight loss, metabolic syndrome parameters, and bone mineral density (BMD) in Chinese adults. We randomized 374 middle-aged subjects (45.8 ± 5.3 years) into 12-week training (45 minutes per day, 5 days per week) of Tai Chi (n = 124) or self-paced walking (n = 121) or control group (n = 129). On average, Tai Chi and walking groups lost 0.50 and 0.76 kg of body weight and 0.47 and 0.59 kg of fat mass after intervention, respectively. The between-group difference of waist circumference (WC) and fasting blood glucose (FBG) was −3.7 cm and −0.18 mmol/L for Tai Chi versus control and −4.1 cm and −0.22 mmol/L for walking versus control. No significant differences were observed regarding lean mass, blood pressure, triglycerides, total cholesterol, high-density and low-density lipoprotein cholesterol, and BMD compared to control. Change in lean mass, not fat mass or total weight loss, was significantly correlated to the change in BMD. Our results suggest that both of these two PAs can produce moderate weight loss and significantly improve the WC and FBG in Hong Kong Chinese adults, with no additional effects on BMD.

Multilevel Approach of a 1-Year Program of Dietary and Exercise Interventions on Bone Mineral Content and Density in Metabolic Syndrome--the RESOLVE Randomized Controlled Trial

Background

Weight loss is a public health concern in obesity-related diseases such as metabolic syndrome (MetS). However, restrictive diets might induce bone loss. The nature of exercise and whether exercise with weight loss programs can protect against potential bone mass deficits remains unclear. Moreover, compliance is essential in intervention programs. Thus, we aimed to investigate the effects that modality and exercise compliance have on bone mineral content (BMC) and density (BMD).

Methods

We investigated 90 individuals with MetS who were recruited for the 1-year RESOLVE trial. Community-dwelling seniors with MetS were randomly assigned into three different modalities of exercise (intensive resistance, intensive endurance, moderate mixed) combined with a restrictive diet. They were compared to 44 healthy controls who did not undergo the intervention.

Results

This intensive lifestyle intervention (15–20 hours of training/week + restrictive diet) resulted in weight loss, body composition changes and health improvements. Baseline BMC and BMD for total body, lumbar spine and femoral neck did not differ between MetS groups and between MetS and controls. Despite changes over time, BMC or BMD did not differ between the three modalities of exercise and when compared with the controls. However, independent of exercise modality, compliant participants increased their BMC and BMD compared with their less compliant peers. Decreases in total body lean mass and negative energy balance significantly and independently contributed to decreases in lumbar spine BMC.

Conclusion

After the one year intervention, differences relating to exercise modalities were not evident. However, compliance with an intensive exercise program resulted in a significantly higher bone mass during energy restriction than non-compliance. Exercise is therefore beneficial to bone in the context of a weight loss program.

Trial Registration

ClinicalTrials.gov NCT00917917

Prevalence of low bone mineral density in female dancers

BACKGROUND AND OBJECTIVE

While some authors report that dancers have reduced bone mineral density (BMD) and increased risk of osteoporosis, others have stressed the positive effects of dance training on developing healthy BMD. Given the existing controversy, the aim of this systematic review was to examine the best evidence-based information available in relation to female dancers.

METHODS

Four databases (Web of Science, PubMed, EBSCO, Scopus) and two dance science journals (Journal of Dance Medicine and Science and Medical Problems of Performing Artists) were searched for relevant material using the keywords "dance", "ballet", "BMD", "bone density", "osteoporosis" and "female athlete triad syndrome". A total of 257 abstracts were screened using selected inclusion (studies involving bone measurements in dancers) and exclusion (editorials, opinion papers, chapters in books, narrative reviews and non-English language papers) criteria according to PRISMA guidelines. Following the above screening, a total of 108 abstracts were identified as potentially relevant. After the exclusion of conference proceedings, review papers, studies focusing only in male dancers and studies in which dancers' information were combined with other athletes, the eligible papers were subsequently assessed using the GRADE system and grouped according to: (1) prevalence of low BMD and associated factors, (2) incidence of low BMD and risk factors, (3) prevention/treatment of low BMD in dancers, and (4) other studies.

RESULTS

Of the 257 abstracts that were initially screened, only 35 studies were finally considered. Only one of these 35 was of high quality, while the remaining 34 were of relatively low quality. Seven studies reported prevalence of low BMD and associated factors, 10 reported associated factors with no prevalence data, while one reported prevalence with no associated factors data. One study cited risk factors, while another one elaborated on the treatment of low BMD in dancers. The remaining 15 studies were classified as "other studies".

CONCLUSIONS

It remains unclear whether low BMD is prevalent in female dancers. The present review highlights the need for high-quality BMD research in this area.

The osteogenic effects of swimming on bone mass, strength, and microarchitecture in rats with unloading-induced bone loss

The effect of nonweight-bearing exercise on osteoporotic bones remains controversial and inconclusive. The purpose of this study was to evaluate the effects of swimming on osteoporotic tibias of rats submitted to hindlimb suspension. Initially, 20 Wistar rats were used to confirm a significant bone loss following 21 days of unloading. Thirty rats were then divided into 3 groups and followed during 51 days: CON (nonsuspended rats), S + WB (suspended rats for 21 days and then released for regular weight-bearing) and, S + Swim (suspended rats for 21 days and then released from suspension and submitted to swimming exercise). We observed that swimming exercise was effective at fully recovering the bone deterioration caused by suspension, with significant increments in BMD, bone strength and bone volume. On the other hand, regular weight-bearing failed at fully restoring the bone loss induced by unloading. These results indicate that swimming exercise may be a potential tool to improve bone density, strength, and trabecular volume in tibias with bone loss induced by mechanical unloading in suspended rats. We conclude that this modality of activity could be beneficial in improving bone mass, strength, and architecture in osteoporotic individuals induced by disuse, such as bed rest or those exposed to microgravity, who may not be able to perform weight-bearing exercises.

Physical exercise and osteoporosis: effects of different types of exercises on bone and physical function of postmenopausal women

Physical exercise is an important stimulus for osteoporosis prevention and treatment. However, it is not clear yet which modality would be better to stimulate bone metabolism and enhance physical function of postmenopausal women. This review paper aims to summarize and update present knowledge on the effects of different kinds of aquatic and ground physical exercises on bone metabolism and physical function of postmenopausal women. Moderate to intense exercises, performed in a high speed during short intervals of time, in water or on the ground, can be part of a program to prevent and treat postmenopausal osteoporosis. Mechanical vibration has proven to be beneficial for bone microarchitecture, improving bone density and bone strength, as well as increasing physical function. Although impact exercises are recognized as beneficial for the stimulation of bone tissue, other variables such as muscle strength, type of muscle contraction, duration and intensity of exercises are also determinants to induce changes in bone metabolism of postmenopausal women. Not only osteoanabolic exercises should be recommended; activities aimed to develop muscle strength and body balance and improve the proprioception should be encouraged to prevent falls and fractures.

Effect of 8 weeks of pre-season training on body composition, physical fitness, anaerobic capacity, and isokinetic muscle strength in male and female collegiate taekwondo athletes

The purpose of the study was to determine the effect of 8 weeks pre-season training on body composition, physical fitness, anaerobic capacity, and isokinetic strength in collegiate taekwondo athletes. Thirty-four collegiate athletes (male: 22, female: 12) participated. Body composition, bone mineral density, physical fitness, anaerobic capacity, and isokinetic muscle strength were tested. After statistical analysis was performed the results indicated that there were significant decreases in body weight, percent body fat, and fat tissue after 8 weeks of pre-season training. Bone mineral density increased significantly only in males. There were significant improvements in the 50 m shuttle run and 20 m multistage endurance run in both males and females. The sit & reach test and standing long jump were not significantly changed after 8 weeks. Relative peak power and anaerobic capacity were significantly improved in males. Significant increases in angular velocity were observed for knee extension at both % BW 60°/sec and 180°/sec in both males and females. A significant increase in angular velocity was seen for right knee flexion at % BW 60°/sec for males, but it decreased at % BW 180°/sec for both males and females. In conclusion, this study suggests that 8 weeks of pre-season training has a positive effect on body composition, physical fitness, anaerobic capacity, isokinetic muscular strength, and endurance. Nevertheless, an exercise approach with the goal of increasing lean tissue, and improving power in knee flexors and flexibility of athletes, should be included in the training program.

Development and implementation of a coupled computational muscle force optimization bone shape adaptation modeling method

Improved methods to analyze and compare the muscle-based influences that drive bone strength adaptation can aid in the understanding of the wide array of experimental observations about the effectiveness of various mechanical countermeasures to losses in bone strength that result from age, disuse, and reduced gravity environments. The coupling of gradient-based and gradientless numerical optimization routines with finite element methods in this work results in a modeling technique that determines the individual magnitudes of the muscle forces acting in a multisegment musculoskeletal system and predicts the improvement in the stress state uniformity and, therefore, strength, of a targeted bone through simulated local cortical material accretion and resorption. With a performance-based stopping criteria, no experimentally based or system-based parameters, and designed to include the direct and indirect effects of muscles attached to the targeted bone as well as to its neighbors, shape and strength alterations resulting from a wide range of boundary conditions can be consistently quantified. As demonstrated in a representative parametric study, the developed technique effectively provides a clearer foundation for the study of the relationships between muscle forces and the induced changes in bone strength. Its use can lead to the better control of such adaptive phenomena.

The relationship between lower limb bone and muscle in military recruits, response to physical training, and influence of smoking status

The relationship between bone and skeletal muscle mass may be affected by physical training. No studies have prospectively examined the bone and skeletal muscle responses to a short controlled exercise-training programme. We hypothesised that a short exercise-training period would affect muscle and bone mass together. Methods: Femoral bone and Rectus femoris Volumes (RF_VOL) were determined by magnetic resonance imaging in 215 healthy army recruits, and bone mineral density (BMD) by Dual X-Ray Absorptiometry (DXA) and repeated after 12 weeks of regulated physical training. Results: Pre-training, RF_VOL was smaller in smokers than non-smokers (100.9 ± 20.2 vs. 108.7 ± 24.5, p = 0.018; 96.2 ± 16.9 vs. 104.8 ± 21.3, p = 0.002 for dominant/non-dominant limbs), although increases in RF_VOL with training (of 14.2 ± 14.5% and 13.2 ± 15.6%] respectively, p < 0.001) were independent of prior smoking status. Pre-training RF_VOL was related to bone cortical volume (r² = 0.21 and 0.30, p < 0.001 for dominant and non-dominant legs), and specifically to periosteal (r² = 0.21 and 0.23, p < 0.001) volume. Pre-training dominant RF_VOL was independently associated with Total Hip BMD (p < 0.001). Training-related increases in RF_VOL and bone volumes were related. Whilst smokers demonstrated lower muscle mass than non-smokers, differences were abolished with training. Training-related increases in muscle mass were related to increases in periosteal bone volume in both dominant and non-dominant legs.

Combined effects of interaction between physical activity and nutrition on bone health in children and adolescents: a systematic review

CONTEXT

Osteoporosis is a major public health concern worldwide. Understanding the roles of diet and physical activity in ensuring adequate bone mass accrual during childhood and adolescence may help identify strategies to reduce the risk of osteoporotic fractures later in life.

OBJECTIVE

The present systematic review was conducted to provide an overview of the current knowledge of the combined effects of physical activity and diet on bone mass accrual in children and adolescents.

DATA SOURCES

Data were obtained via searches of the PubMed, EMBASE, SPORTDiscus, and ISI Web of Science databases.

STUDY SELECTION

Studies published in English and Spanish between 1887 and August 2013 were eligible for inclusion. Two investigators evaluated the studies against the inclusion and exclusion criteria. A total of 14 studies (7 cross-sectional and 7 experimental) were included in the review.

DATA EXTRACTION

The Pedro score and the Black and Down's checklist were used to evaluate the methodological quality of the experimental and the cross-sectional studies, respectively. Study characteristics were summarized in accordance with the review's PICO criteria.

DATA SYNTHESIS

Significant exercise-by-calcium interaction was detected at several different bone sites.

CONCLUSIONS

Although the results of cross-sectional studies were inconsistent, the results of randomized controlled trials showed that exercise has the potential to improve bone health under conditions of adequate calcium intake.

Exercises including weight vests and a patient education program for women with osteopenia: a feasibility study of the OsteoACTIVE rehabilitation program

STUDY DESIGN

Prospective case series with 1-year follow-up.

OBJECTIVES

The primary aim was to describe the OsteoACTIVE rehabilitation program and evaluate its feasibility in terms of progression, adherence, and adverse events in patients with low bone mineral density (BMD) and a healed forearm fracture. The secondary aim was to assess changes in measures of function and quality of life.

BACKGROUND

Previous studies have shown benefits of weight-bearing activities, resistance exercises, and balance and coordination training for women with low BMD and older adults. However, no studies, to our knowledge, have described or examined a rehabilitation program combining the use of weight vests and patient education in patients with low BMD.

METHODS

Forty-two postmenopausal women with osteopenia and a healed forearm fracture attended the OsteoACTIVE program for 6 months (3 sessions of 60 minutes per week). Feasibility was assessed by documenting training progression (load and exercises), program adherence (aiming for greater than 80%), and adverse events (joint pain, muscle soreness, and falls). Secondary measures included quadriceps strength, BMD, dynamic balance, walking ability, and self-report functional outcome measures. All outcome measures were recorded preintervention (baseline), postintervention, and at 1-year follow-up.

RESULTS

Thirty-five women (83%) completed the 6-month program and 31 women (74%) attended all the follow-up measurement sessions. All participants progressed during the rehabilitation program for both load and type of exercises. Furthermore, 87% of the participants met the a priori goal of 80% adherence, and no participants reported adverse events. Improvements in quadriceps strength and BMD of the femoral trochanter were noted at the end of the 6-month training period (P<.05). At 1-year follow-up, there were significant improvements in quadriceps strength and dynamic balance compared to baseline (P<.05).

CONCLUSION

The OsteoACTIVE rehabilitation program was feasible and achieved progression of training level, had high adherence, and had no adverse events. Positive improvements were established in lower extremity function and femoral trochanter BMD. Clinical trial registered at ClinicalTrials.gov (NCT01357278).

LEVEL OF EVIDENCE

Therapy, level 4.

The effects of swimming training on bone tissue in adolescence

The aim was to analyze bone mineral content (BMC) and density (BMD) in regular swimming trained adolescents and the interaction that weigh-bearing sports may have on these values. Bone mass was evaluated by dual energy x-ray absorptiometry (DXA) and quantitative ultrasound (QUS) in 77 swimmers (34 females/43 males) and 52 normoactive controls (CG; 23 females/29 males) from 11 to 18 years. Swimmers who had performed or were performing other sports (OSP; 11 females/20 males) were compared with pure swimmers (PSW; 23 females/23 males). Both groups were compared with CG. Bone values were compared using analyses of covariance adjusting for height, calcium intake, subtotal lean (whole body lean minus head), and pubertal status. Male PSW showed lower BMD and BMC at several sites than male CG. However, for male OSP, only lumbar spine BMC was lower in OSP than male CG. Male PSW showed lower BMD and BMC when compared with male OSP. Female PSW showed higher arm BMD and lower leg BMC than female CG, while female OSP only presented lower leg BMC than female CG. Contrary to males, female-PSW presented higher BMD and BMC than female OSP. No differences in QUS values were found between swimmers and CG. To summarize, although more information is needed for females, it seems that for males, swimming is associated with lower BMC and BMD.