Effects of resistance training on regional and total bone mineral density in premenopausal women: a randomized prospective study

Vascular function in hypertension: does gender dimension matter?

Blood pressure and vascular ageing trajectories differ between men and women. These differences develop due to sex-related factors, attributable to sex chromosomes or sex hormones, and due to gender-related factors, mainly related to different sociocultural behaviors. The present review summarizes the relevant facts regarding gender-related differences in vascular function in hypertension. Among sex-related factors, endogenous 17ß-estradiol plays a key role in protecting pre-menopausal women from vascular ageing. However, as vascular ageing (preceding and inducing hypertension) has a steeper increase in women than in men starting already from the third decade, it is likely that gender-related factors play a prominent role, especially in the young. Among gender-related factors, psychological stress (including that one related to gender-based violence and discrimination), depression, some psychological traits, but also low socioeconomic status, are more common in women than men, and their impact on vascular ageing is likely to be greater in women. Men, on the contrary, are more exposed to the vascular adverse consequences of alcohol consumption, as well as of social deprivation, while "toxic masculinity" traits may result in lower adherence to lifestyle and preventive strategies. Unhealthy diet habits are more prevalent in men and smoking is equally prevalent in the two sexes, but have a disproportional negative effect on women's vascular health. In conclusion, given the major and complex role of gender-related factors in driving vascular alterations and blood pressure patterns, gender dimension should be systematically integrated into future research on vascular function and hypertension and to tailor cardiovascular prevention strategies.

Resistance Training for Patients with Cancer: A Conceptual Framework for Maximizing Strength, Power, Functional Mobility, and Body Composition to Optimize Health and Outcomes

There are many benefits to the addition of exercise to cancer treatment and survivorship, particularly with resistance training regimens that target hypertrophy, bone mineral density, strength, functional mobility, and body composition. These goals are best achieved through a series of individualized high-intensity compound movements that mirror functional mobility patterns and sufficiently stress the musculoskeletal system. As a result of adequate stress, the body will engage compensatory cellular mechanisms that improve the structural integrity of bones and muscles, stimulate metabolism and the immune system, optimize functional performance, and minimize mechanical injury risk. The current evidence suggests that application of the above exercise principles, practiced in a safe environment under expert observation, may offer patients with cancer an effective means of improving overall health and cancer-specific outcomes. The following article poses several important questions certified exercise specialists and physicians should consider when prescribing resistance exercise for patients with cancer.

Global trends and hotspots in research on osteoporosis rehabilitation: A bibliometric study and visualization analysis

Background

The field of rehabilitation medicine plays an essential role in the comprehensive management of osteoporosis and its consequences. The benefits of therapeutic exercise are increasingly being recognized in this area, which receives an increasing number of publications. this study was designed to comprehensively identify collaborative networks, parse and track research trends, spotlight present hotspots, and accurately predict frontiers and focus on the health topics related to osteoporosis rehabilitation.

Methods

This research adopted computer retrieval of osteoporosis rehabilitation-related research published in the Web of Science Core Collection (WoSCC) from inception to June 14, 2022. The bibliometric visualization and comparative analysis involving countries, institutions, journals, authors, references, and keywords were performed using the CiteSpace and VOSviewer software.

Results

A total of 3,268 articles were included, and the number of articles published each year has demonstrated a steady increase. The United States and the University of Melbourne were the highest productive country and institution, with 1,325 and 87 articles, respectively. The journal of osteoporosis international has published the greatest number of articles, with 221 publications, and the journal of bone and mineral research ranked first in the co-citation counts (cited by 11,792 times). The most productive and highly-cited authors were Heinonen A and Cummings S, with 35 publications and 680 citations.

Conclusions

At present, "physical activity," "weight bearing exercise," "muscle strength," "whole body vibration," "postmenopausal women," "older women," children, men are the noteworthy research hot topics. Future research that focus on the major modes and parameters of physical activity/exercise for osteoporosis (including whole body vibration, weight bearing exercises, resistance training), targeted multicomponent training regimens, rehabilitation therapy for postmenopausal women, older women, children and men, osteoporosis related-sarcopenia and fractures, and mesenchymal stem cells are becoming frontiers and focus on the health topics related to osteoporosis rehabilitation in the upcoming years, which are worthy of further exploration.

The association between body fat distribution and bone mineral density: evidence from the US population

OBJECTIVE

To investigate the association between different body fat distribution and different sites of BMD in male and female populations.

METHODS

Use the National Health and Nutrition Examination Survey (NHANES) datasets to select participants. The weighted linear regression model investigated the difference in body fat and Bone Mineral Density (BMD) in different gender. Multivariate adjusted smoothing curve-fitting and multiple linear regression models were used to explore whether an association existed between body fat distribution and BMD. Last, a subgroup analysis was performed according to age and gender group.

RESULTS

Overall, 2881 participants were included in this study. Compared to males, female participants had lower BMD (P < 0.05) and higher Gynoid fat mass (P < 0.00001), while there was no difference between Android fat mass (P = 0.91). Android fat mass was positively associated with Total femur BMD (Males, β = 0.044, 95% CI = 0.037, 0.051, P < 0.00001; Females, β = 0.044, 95% CI = 0.039, 0.049, P < 0.00001), Femoral neck BMD (Males, β = 0.034, 95% CI = 0.027, 0.041, P < 0.00001; Females, β = 0.032, 95% CI = 0.027, 0.037, P < 0.00001), and Total spine BMD (Males, β = 0.036, 95% CI = 0.029, 0.044, P < 0.00001; Females, β = 0.025, 95% CI = 0.019, 0.031, P < 0.00001). The Gynoid fat mass, subgroup analysis of age and ethnicity reached similar results.

CONCLUSION

Body fat in different regions was positively associated with BMD in different sites, and this association persisted in subgroup analyses across age and race in different gender.

The Benefits of Utilizing Total Body Composition as a Predictor of Cardiorespiratory Fitness Based on Age: A Pilot Study

Maximal oxygen consumption (VO2max) has been associated with body fat percentage (%BF) or fat free mass. However, most analyses do not consider total body composition (TBC) as defined by %BF, fat free mass index (FFMI—a height-adjusted measure of muscle mass), visceral adipose tissue, and bone mineral content (BMC). The aim of this study was to determine if TBC predicts cardiorespiratory fitness in healthy adults and if a relationship exists in young and older adults. Sixty healthy individuals (age group 1 (AG1, ≤35 years), n = 35; age group 2 (AG2, >35 years), n = 25) were screened in a cross-sectional study and retrospectively examined. All participants completed a full body DEXA scan and a standardized multistage treadmill test to determine VO2max. A multiple linear regression analysis was performed to examine the relationship between TBC and VO2max. The multiple regression model showed an overall significant effect for TBC (p < 0.001, R2 = 0.282). When analyzed by age group, the regression model of TBC was not significant in young adults (AG1, p = 0.319, R2 = 0.141), but significant in older adults (AG2, p < 0.001, R2 = 0.683). Significant predictors of VO2max in the older cohort were %BF (β = −0.748, p = 0.001) and BMC (β = 0.014, p = 0.002). Total body composition predicted VO2max in a small cohort of healthy adults. This study highlights the importance of TBC for cardiovascular health, especially in mid-to later-life individuals.

Uncovering the Bone-Muscle Interaction and Its Implications for the Health and Function of Older Adults (the Wellderly Project): Protocol for a Randomized Controlled Crossover Trial

BACKGROUND

Bone and muscle are closely linked anatomically, biochemically, and metabolically. Acute exercise affects both bone and muscle, implying a crosstalk between the two systems. However, how these two systems communicate is still largely unknown. We will explore the role of undercarboxylated osteocalcin (ucOC) in this crosstalk. ucOC is involved in glucose metabolism and has a potential role in muscle maintenance and metabolism.

OBJECTIVE

The proposed trial will determine if circulating ucOC levels in older adults at baseline and following acute exercise are associated with parameters of muscle function and if the ucOC response to exercise varies between older adults with low muscle quality and those with normal or high muscle quality.

METHODS

A total of 54 men and women aged 60 years or older with no history of diabetes and warfarin and vitamin K use will be recruited. Screening tests will be performed, including those for functional, anthropometric, and clinical presentation. On the basis of muscle quality, a combined equation of lean mass (leg appendicular skeletal muscle mass in kg) and strength (leg press; one-repetition maximum), participants will be stratified into a high or low muscle function group and randomized into the controlled crossover acute intervention. Three visits will be performed approximately 7 days apart, and acute aerobic exercise, acute resistance exercise, and a control session (rest) will be completed in any order. Our primary outcome for this study is the effect of acute exercise on ucOC in older adults with low muscle function and those with high muscle function.

RESULTS

The trial is active and ongoing. Recruitment began in February 2018, and 38 participants have completed the study as of May 26, 2019.

CONCLUSIONS

This study will provide novel insights into bone and muscle crosstalk in older adults, potentially identifying new clinical biomarkers and mechanistic targets for drug treatments for sarcopenia and other related musculoskeletal conditions.

TRIAL REGISTRATION

Australia New Zealand Clinical Trials Registry ACTRN12618001756213; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375925.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/18777.

Bone Mineral Density Differences Across Female Olympic Lifters, Power Lifters, and Soccer Players

ABSTRACT

Jeon, W, Harrison, JM, Stanforth, PR, and Griffin, L. Bone mineral density differences across female Olympic lifters, power lifters, and soccer players. J Strength Cond Res 35(3): 638-643, 2021-Athletic training improves bone mineral density (BMD) through repeated mechanical loading. The location, intensity, and direction of applied mechanical pressure play an important role in determining BMD, making some sports more advantageous at improving BMD at specific regions. Thirty-seven (10 power lifters [PL], 8 Olympic lifters [OL], 8 soccer players [SP], and 11 recreationally active [RA]) women participated in a cross-sectional study. We measured lumbar spine (L1-L4), femoral neck, total-body BMD, and overall body composition (total fat mass, lean mass, percent body fat) with dual-energy x-ray absorptiometry. All athletic groups had greater total BMD than RA (p = 0.01 [PL]; p < 0.001 [OL]; p = 0.01 [SP]). Olympic lifters had the highest total BMD than all other athletic groups. Olympic lifters had the significantly greater total BMD than PL (p = 0.018), but there was no difference in total BMD between PL and SP. As compared with RA, OL showed greater BMD at both the total lumbar spine (p = 0.002) and the femoral neck (p = 0.007), whereas PL showed greater BMD only for the total lumbar spine (p = 0.019) and SP showed greater BMD only for the femoral neck (p = 0.002). Olympic-style lifting includes both high-impact and odd-impact loading modalities that are associated with the highest BMD at both the lumbar spine and femoral neck.

Regional changes in indices of bone strength of upper and lower limbs in response to high-intensity impact loading or high-intensity resistance training

It is well known that the bone response to physical activity is highly dependent on the nature of the loads imposed. Despite this, few direct comparisons of the effect of impact-style loading and resistance training on bone have been made. We therefore aimed to compare the effects of 10-month, twice-weekly, high-impact loading and 10-month, twice-weekly, high-intensity resistance training on indices of bone strength of both the upper and lower limbs of young adult women. Physically inactive, otherwise healthy, young adult women (18-30 years) with below average bone mass (T-score ≤ 0) were recruited as part of the OPTIMA-Ex trial. Testing included DXA- and pQCT-derived measures of bone mass and indices of bone strength and QUS-derived measures of bone quality of the dominant (D) and non-dominant (ND) upper (radius) and lower limbs (femoral neck, tibia, calcaneus). The present study examined those participants who completed the impact training (IT; n = 10) and resistance training (RT; n = 12) arms of the trial. Age differed between groups at baseline (IT = 23.2 ± 3.8 years, RT = 20.5 ± 1.8 years; p = 0.042). Compliance with the training programs did not differ (IT = 61.4 ± 15.1%, RT = 66.4 ± 11.2%, p = 0.381). Age and baseline differences in bone outcomes served as covariates for repeated measures and univariate ANCOVA conducted for dependent variables and percent change respectively. IT improved distal pQCT-derived bone mineral density (BMD) of the upper limb (ND radius: total BMD = 8.55 ± 2.26% versus 1.50 ± 2.04%, p = 0.040 and trabecular BMD = 1.86 ± 0.90% versus -1.30 ± 0.81%, p = 0.029) and lower limb (ND tibia trabecular BMD = 1.22 ± 0.55% versus -0.82 ± 0.50%, p = 0.017), more than RT. IT also improved upper limb bone strength index (BSI) (ND radius total BSI = 15.35 ± 2.83% versus 2.67 ± 2.55, p = 0.005) and lower limb BSI (D tibia total BSI = 5.16 ± 1.13% versus 0.37 ± 1.02%, p = 0.008; D tibia trabecular BSI = 3.93 ± 1.76% versus -2.84 ± 1.59, p = 0.014, ND tibia trabecular BSI = 3.57 ± 1.63% versus -3.15 ± 1.48%, p = 0.009) more than RT. Conversely, RT improved DXA-derived cortical volumetric BMD at the femoral neck more than IT (3.68 ± 1.99% versus -4.14 ± 2.20%, p = 0.021). Results suggest that IT and RT provide differing site-specific effects in both the upper and lower limbs, with superior bone responses observed at the distal segment from IT, while RT appeared to have greater effect on the shaft of the bone, on indices of bone-strength in young adult women.

The effect of long-distance running on bone strength and bone biochemical markers

It still remains controversial whether exercise will help or adversely affect the bone formation. The aim of this study was to evaluate the effect of common long-distance running on the magnitude of change in bone properties as measured by quantitative ultrasound (QUS) and bone biochemical markers. Subjects included 68 long-distance runners and 40 controls. Long-distance runners had been training in the marathon club for at least 6 months, the average period of exercise was 2 years, and running at 48.6±24.9 km per week. Otherwise, controls were people who had not experienced any specific sports before. Bone speed of sound (SOS) was measured by QUS at the distal one third radius and the mid-shaft of the tibia. Serum osteocalcin and urine deoxypyridinolin were measured in all groups. No significant differences were found in tibial and radial SOS between the two groups. Serum osteocalcin was higher in long-distance runners than control (P<0.05) in both the 30s and 40s of the participants, but urine deoxypyridinolin showed no significant difference between the two groups. It is concluded that long-distance running at the club level increases bone formation marker, but seems to do no harmful effect on bone properties as measured by QUS.

Exercise for the prevention of osteoporosis in postmenopausal women: an evidence-based guide to the optimal prescription

BACKGROUND

Osteoporosis and related fragility fractures are a global public health problem in which pharmaceutical agents targeting bone mineral density (BMD) are the first line of treatment. However, pharmaceuticals have no effect on improving other key fracture risk factors, including low muscle strength, power and functional capacity, all of which are associated with an increased risk for falls and fracture, independent of BMD. Targeted exercise training is the only strategy that can simultaneously improve multiple skeletal and fall-related risk factors, but it must be appropriately prescribed and tailored to the desired outcome(s) and the specified target group.

OBJECTIVES

In this review, we provide an overview of the general principles of training and specific loading characteristics underlying current exercise guidelines for the prevention of osteoporosis, and an update on the latest scientific evidence with regard to the type and dose of exercise shown to positively influence bone mass, structure and strength and reduce fracture risk in postmenopausal women.

Maximal strength training improves musculoskeletal health in amphetamine users in clinical treatment

Amphetamine use leads to impaired skeletal health and elevated risk of osteoporosis. In the current study, we document that maximal strength training (MST), as a part of clinical treatment, works as a countermeasure, improving muscle force generating capacity, body composition, and skeletal health at sites particularly prone to osteoporotic fractures.

INTRODUCTION

Amphetamine users have attenuated musculoskeletal health. MST with heavy loads, few repetitions, and emphasis on maximal mobilization in the concentric phase may increase muscle force generating capacity and skeletal health. This study investigated if MST-induced improvements in force generating capacity improved bone mineral density (BMD), trabecular bone score, and body composition in amphetamine users participating in 3-months clinical treatment.

METHODS

Of 40 randomized patients, 23 completed the study: 11 in the supervised training group (TG; 8 men, 3 women, 34 ± 10 years) and 12 in the control group (CG; 9 men, 3 women, 32 ± 8 years). The TG performed hack-squat MST three times a week for 12 weeks with an intensity of ~90% of one repetition maximum (1RM). Both groups attended conventional clinical treatment. Pre-training and post-training, we assessed hack-squat 1RM and rate of force development (RFD), BMD, body composition and trabecular bone score by dual X-ray absorptiometry, and serum bone metabolism markers.

RESULTS

MST induced increases in 1RM (70%) and RFD (86%), and resulted in BMD improvements at lumbar spine (3.6%) and total hip (2.4%); all improvements were different from CG (p < 0.05). Both the 1RM and RFD increases were associated with BMD improvements (lumbar spine: r = 0.73 (1RM), r = 0.60 (RFD); total hip: r = 0.61 (1RM); all p < 0.05). No differences were observed in trabecular bone score or bone metabolism markers.

CONCLUSIONS

MST improved force generating capacity and skeletal health at sites prone to bone loss in amphetamine users, and advocate that MST should be implemented as a clinical strategy to restore the patients' musculoskeletal health.

Bone mineral density, hand grip strength, smoking status and physical activity in Polish young men

The human skeleton undergoes constant changes encompassing the phases of growth, consolidation and involution of the bone tissue. The aim of the research was to assess the relationship between bone mineral density (BMD) and such factors as hand grip strength, somatic structure or attitudes to tobacco smoking in men with different levels of physical activity. The study included 172 males aged 20-30 years. Mineral density and forearm bone mass were measured using the dual-energy X-ray absorptiometry method. Physical activity levels were assessed with the use of the International Physical Activity Questionnaire. Hand grip strength was measured with Jamar hand dynamometer. Attitudes towards smoking were assessed using the Global Adult Tobacco Survey. The correlation between a high level of physical activity among men and higher BMD and bone mass both in the distal and proximal parts of the forearm was statistically significantly greater compared to individuals with an insufficient level of physical activity. A better state of BMD and higher bone mass in both forearm bones was noted among non-smoking men. A high level of physical activity was the most significant predictor of BMD in the distal part of the forearm. The regression analysis in the proximal part revealed that body mass and a high level of physical activity were the most important predictors of BMD. The lack of physical activity was associated with more frequent occurrence of low bone mass in men. Tobacco smoking may be one of the most important risk factors of poor bone mineralization in young men.

Bone Health following Bariatric Surgery: Implications for Management Strategies to Attenuate Bone Loss

Bariatric surgery (BS) is an effective treatment for morbid obesity and its associated comorbidities. Following such a procedure, however, patients are at risk of developing metabolic bone disease owing to the combination of rapid weight loss, severely restricted dietary intake, and reduced intestinal nutrient absorption. Patients undergoing malabsorptive procedures are at a higher risk of postoperative bone health deterioration than those undergoing restrictive procedures; however, studies have demonstrated negative skeletal consequences of restrictive procedures as well. The clinical practice guidelines of some international associations have previously addressed preoperative evaluation and postoperative clinical care in order to maintain bone health in BS patients. Nevertheless, some issues regarding bone health in BS patients remain unclear owing to the lack of relevant randomized clinical trials, including doses of nutritional supplements pre- and post-BS. This review summarizes the current data regarding the skeletal consequences of BS and its mechanisms, with an emphasis on the preventive strategies and nutritional care that may be warranted in order to attenuate bone deterioration following BS.

A protocol for a randomised controlled trial of the bone response to impact loading or resistance training in young women with lower than average bone mass: the OPTIMA-Ex trial

INTRODUCTION

The aim of the Osteoporosis Prevention Through Impact and Muscle-loading Approaches to Exercise trial is to compare the bone response to two known osteogenic stimuli - impact loading exercise and resistance training. Specifically, we will examine the effect of a 10-month, twice-weekly, high-intensity impact loading exercise intervention and a 10-month, twice-weekly, high-intensity resistance training intervention on bone mass and strength at clinically important skeletal sites. The intervention groups will be compared against a home-based 'positive' control group. Safety and acceptability of each exercise modality will also be determined.

METHODS AND ANALYSIS

Sedentary otherwise healthy young women aged 18-30 years with bone mineral density (BMD) T-scores less than or equal to 0 at the hip and lumbar spine, screened for conditions and medications that influence bone and physical function, will be recruited. Eligible participants are randomised to 10-month, twice-weekly, either supervised high-intensity impact training, high-intensity resistance training or a home-based 'positive' control group. The primary outcome measure will be lumbar spine areal BMD, while secondary outcome measures will include: whole body, femoral neck and regional measures (upper and lower limb) of bone, muscle and fat; anthropometrics; muscle strength and power; quality of life and exercise safety, enjoyment and acceptability. All outcome measures will be conducted at baseline (T0) and 10 months (T10) and will be analysed according to the intention-to-treat principle and per protocol.

ETHICS AND DISSEMINATION

The study has been granted ethical approval from the Griffith University Human Research Ethics Committee (GU Ref: 2015/775). Standard scientific reporting practices will occur, including publication in peer-reviewed journals. Participant confidentiality will be maintained in all forms of reporting.

TRIAL REGISTRATION NUMBER

ACTRN12616001444471.

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.

Effects of lifestyle exercise on premenopausal bone health: a randomised controlled trial

Osteoporosis, a slowly evolving public health epidemic, often with an insidious presentation is largely preventable but the optimal dimensions of exercise that may be prescribed for enhancing bone-health among premenopausal adults are yet to be elucidated. Hence, the escalating incidence and burden of prevalence of osteoporosis is yet unabated. Considering that exogenous hormones in the form of hormonal contraception are known to modulate bone mass, investigations of their possible influence on the translation of exercise-induced osteogenic stimuli on the mature bone is pertinent. The aim of this study was to examine the effect of specified lifestyle exercise on bone-health of premenopausal women. Premenopausal women (n = 96, mean age: 22.25 ± 3.5 years; mean BMI: 23.43 ± 3.5 kg/m(2)) participated in a 6-month randomised controlled trial involving home-based rest-interspersed bouts of high-impact exercise for the intervention group and sham exercise for the control group. Approximately half (47) of the participants (24-exercise, 23-control) were on hormonal-based contraception while the other half (49: 24-exercise, 25-control) were not on hormonal contraception. The regime led to a significant 3.7 % increase in broadband ultrasound attenuation of exercisers compared to controls; hormonal contraceptive use did not appear to potentiate the osteogenic effects of the lifestyle exercise regime. The research highlights that short, discrete bouts of high-impact exercise may be a potential public health prescription for enhancing premenopausal bone-health regardless of hormonal contraceptive use.

Effect of Moderate Aerobic Training on Bone Metabolism Indices among Adult Humans

Objective: This study assessed the osteogenic effect (T-Score) and changes in bone markers in healthy subjects by 12-weeks of aerobic training.

Methods: Total 65 healthy subjects (36 males, 29 females), their age ranged between 30 and 60 years with normal body mass index, were recruited to participate in this study and they were selected among healthy subjects who do not have any metabolic disorders and were not receiving any medication that could affect the bone turnover. Standardized physical examination and collection of serum samples were performed at base line and after 12 weeks of moderate aerobic training to measure bone formation markers (osteocalcin (OC) and bone specific alkaline Phosphatase (BAP) and bone resorption marker Deoxypyridinoline (DPD), and serum calcium. Each subject participated in exercise training program for 12 weeks, three times per week.

Results: The results showed that the 12 weeks of moderate aerobic training produced a significant improvement in all bone metabolism indices including Serum bone-specific alkaline phosphatase, serum osteocalcin, serum free Calcium and bone mineral density among all subjects.

Conclusion: Moderate intensity of aerobic training exerts significant positive effects on bone formation marker and bone density associated with a significant decrease in the rate of bone resorption that could assist in preventing or decelerating osteoporosis.

Early-phase musculoskeletal adaptations to different levels of eccentric resistance after 8 weeks of lower body training

PURPOSE

Eccentric muscle actions are important to the development of muscle mass and strength and may affect bone mineral density (BMD). This study's purpose was to determine the relative effectiveness of five different eccentric:concentric load ratios to increase musculoskeletal parameters during early adaptations to resistance training.

METHODS

Forty male subjects performed a supine leg press and calf press training program 3 days week(-1) for 8 weeks. Subjects were matched for pre-training leg press 1-repetition maximum strength (1-RM) and randomly assigned to one of five training groups. Concentric training load (% 1-RM) was constant across groups, but within groups, eccentric load was 0, 33, 66, 100, or 138% of concentric load. Muscle mass (dual energy X-ray absorptiometry; DXA), strength (1-RM), and BMD (DXA) were measured pre- and post-training. Markers of bone metabolism were assessed pre-, mid- and post-training.

RESULTS

The increase in leg press 1-RM in the 138% group (20 ± 4%) was significantly greater (P < 0.05) than the 0% (8 ± 3%), 33% (8 ± 5%) and 66% (8 ± 4%) groups, but not the 100% group (13 ± 6 %; P = 0.15). All groups, except the 0% group, increased calf press 1-RM (P < 0.05). Leg lean mass and greater trochanter BMD were increased only in the 138% group (P < 0.05).

CONCLUSIONS

Early-phase adaptations to eccentric overload training include increases in muscle mass and site-specific increases in BMD and muscle strength which are not present or are less with traditional and eccentric underload training. Eccentric overload provides a robust musculoskeletal stimulus that may benefit bedridden patients, individuals recovering from injury or illness, and astronauts during spaceflight.

The Role of Mechanical Stimulation in Recovery of Bone Loss-High versus Low Magnitude and Frequency of Force

Musculoskeletal pathologies associated with decreased bone mass, including osteoporosis and disuse-induced bone loss, affect millions of Americans annually. Microgravity-induced bone loss presents a similar concern for astronauts during space missions. Many pharmaceutical treatments have slowed osteoporosis, and recent data shows promise for countermeasures for bone loss observed in astronauts. Additionally, high magnitude and low frequency impact such as running has been recognized to increase bone and muscle mass under normal but not microgravity conditions. However, a low magnitude and high frequency (LMHF) mechanical load experienced in activities such as postural control, has also been shown to be anabolic to bone. While several clinical trials have demonstrated that LMHF mechanical loading normalizes bone loss in vivo, the target tissues and cells of the mechanical load and underlying mechanisms mediating the responses are unknown. In this review, we provide an overview of bone adaptation under a variety of loading profiles and the potential for a low magnitude loading as a way to counteract bone loss as experienced by astronauts.

A school-based resistance intervention improves skeletal growth in adolescent females

SUMMARY

Twenty-two sixth-grade girls who participated in a 7-month school-based resistance-training program were compared to 22 controls. In a subanalysis of Tanner breast II (T2) and III (T3) subjects (n = 21 controls subjects (CON), n = 17 subjects in the high-intervention (INT)-dose group (HI)), T2 HI had greater narrow neck (NN) width gains than T2 CON (p < 0.05) and T3 HI had greater L3 bone mineral density (BMD) gains than T3 CON (p < 0.05).

INTRODUCTION

Physical activity modulates bone growth during adolescence, but an effective activity has not been identified for general use. The purpose of this study was to examine the effect of a school-based resistance-training program on skeletal growth in pre-menarcheal females.

METHODS

Sixth-grade girls participated in a 7-month, resistance-training program (INT) embedded in physical education (PE) classes. Age- and maturity-matched CON from a neighboring school participated in the standard PE classes. INT dose defined high (HI) and low (LO) groups. At baseline (BL) and follow-up (FU), non-INT organized physical activity (PA, hours per week) and maturity status were recorded; DXA scans assessed total body, distal radius, proximal femur, and lumbar spine. Regression models analyzed growth in bone outcomes for HI versus CON, accounting for age, Tanner stage, height, and PA.

RESULTS

Forty-four girls (22 HI, 22 CON) were 11.7 ± 0.3 years of age at BL; all were ≤6 months postmenarche and did not differ in bone growth over the course of the intervention (p > 0.05). However, in a subanalysis limited to subjects who were T2 or T3 at BL (n = 21 CON, n = 17 HI), T2 HI had greater gains in NN width (p = 0.01) compared to T2 CON, while T3 HI had greater gains in L3 BMD (p = 0.03) compared to T3 CON.

CONCLUSIONS

In a group of T2 and T3 sixth-grade girls, a school-based resistance-training intervention produced maturity-specific differential gains for HI versus CON at the hip and spine.

The effect of swiss ball stabilization exercise on pain and bone mineral density of patients with chronic low back pain

[Purpose] The purpose of this study was to carry out a 16-week treatment of lumbar stabilization exercise with a ball targeting patients with chronic low back pain and investigate its effect on alleviation of low back pain and bone mineral density. [Subjects and Methods] The subjects of this study were 36 patients who were diagnosed with chronic low back pain. They were divided into a conservative treatment group (CTG, n=12), floor exercise group (FEG, n=12), and ball exercise group (BEG, n=12). The degree of recovery from pain was looked into using a visual analogue scale (VAS) and DEXXUM T (OsteoSys, Seoul, Korea) which was used to observe the changes in bone mineral density. [Result] Although the VAS score was reduced in FEG and BEG with treatment, it was not reduced in CTG. Also, the bone mineral density was increased in FEG and BEG, while it was reduced in CTG. [Conclusion] Lumbar stabilization exercises using a ball are thought to be an effective interventional therapy for the alleviation of chronic low back pain and to increase bone mineral density of patients.

Female Athlete Triad

The passage of Title IX in 1972 resulted in a tremendous increase in the number of females participating in high school and collegiate athletics. This rise in female athletes sparked new focus areas of research in sports medicine related to woman with an important area emerging in 1980, the female athlete triad. This triad consisting of low energy availability, menstrual irregularities, and bone health disruption spans a spectrum of severity and has evolved both in diagnosis and in management throughout the years. Many health questions arise for female athletes and their health care providers, often concerning the most effective management and treatment strategies for this triad. This review examines the research and latest advancements in recognizing and understanding the female athlete triad and explores the most current recommendations for treatment and prevention.

Effects of high-resistance circuit training in an elderly population

The aim of this study was to determine the efficacy of a program of high-resistance circuit (HRC) training, and to compare the effects of HRC to traditional heavy strength (TS) training on strength, muscle size, body composition and measures of cardiovascular fitness in a healthy elderly population. Thirty-seven healthy men and women (61.6±5.3years) were randomly assigned to HRC (n=16), TS (n=14), or a control group (CG, n=7). Training consisted of weight lifting twice a week for 12weeks. Before and after the training, isokinetic peak torque in the upper and lower body, and body composition (dual X-ray absorptiometry) were determined. In addition, cardiovascular parameters were evaluated during an incremental treadmill test. Both HRC and TS groups showed significant increases in isokinetic strength (p<0.001), and the increase was significantly greater in the experimental groups than in CG (p<0.03). There were significant increases in lean mass (HRC, p<0.001; TS, p=0.025) and bone mineral density (HRC, p=0.025; TS, p=0.018) in the experimental groups. Only HRC showed a significant decrease in fat mass (p=0.011); this decrease was significantly greater in HRC than in CG (p=0.039). There were significant improvements in walking economy in the HRC group (p<0.049), although there were no statistical differences between groups. There were no changes in any variables in CG. Hence, HRC training was as effective as TS for improving isokinetic strength, bone mineral density and lean mass. Only HRC training elicited adaptations in the cardiovascular system and a decrease in fat mass.

Exercise and bone mineral density in premenopausal women: a meta-analysis of randomized controlled trials

Objective. Examine the effects of exercise on femoral neck (FN) and lumbar spine (LS) bone mineral density (BMD) in premenopausal women. Methods. Meta-analysis of randomized controlled exercise trials ≥24 weeks in premenopausal women. Standardized effect sizes (g) were calculated for each result and pooled using random-effects models, Z score alpha values, 95% confidence intervals (CIs), and number needed to treat (NNT). Heterogeneity was examined using Q and I(2). Moderator and predictor analyses using mixed-effects ANOVA and simple metaregression were conducted. Statistical significance was set at P ≤ 0.05. Results. Statistically significant improvements were found for both FN (7g's, 466 participants, g = 0.342, 95%  CI = 0.132, 0.553, P = 0.001, Q = 10.8, P = 0.22, I(2) = 25.7%, NNT = 5) and LS (6g's, 402 participants, g = 0.201, 95%  CI = 0.009, 0.394, P = 0.04, Q = 3.3, P = 0.65, I(2) = 0%, NNT = 9) BMD. A trend for greater benefits in FN BMD was observed for studies published in countries other than the United States and for those who participated in home versus facility-based exercise. Statistically significant, or a trend for statistically significant, associations were observed for 7 different moderators and predictors, 6 for FN BMD and 1 for LS BMD. Conclusions. Exercise benefits FN and LS BMD in premenopausal women. The observed moderators and predictors deserve further investigation in well-designed randomized controlled trials.

Dropouts and compliance in exercise interventions targeting bone mineral density in adults: a meta-analysis of randomized controlled trials

Background. Dropouts and compliance to exercise interventions targeting bone mineral density (BMD) in adults are not well established. The purpose of this study was to address that gap. Methods. Meta-analysis of randomized controlled exercise intervention trials in adults ≥18 years of age. The primary outcomes were dropouts in the exercise and control groups as well as compliance to the exercise interventions. A random-effects model was used to pool results. Moderator analyses were conducted using mixed-effects ANOVA-like models and metaregression. Statistical significance was set at P ≤ 0.05. Results. Thirty-six studies representing 3,297 participants (1,855 exercise, 1,442 control) were included. Dropout rates in the exercise and control groups averaged 20.9% (95% CI 16.7%-25.9%) and 15.9% (11.8%-21.1%) while compliance to exercise was 76.3% (71.7%-80.3%). For both exercise and control groups, greater dropout rates were associated with studies conducted in the USA versus other countries, females versus males, premenopausal versus postmenopausal women, younger versus older participants, longer studies (controls only), and high- versus moderate-intensity training (exercisers only). Greater compliance to exercise was associated with being female, home- or facility-based exercise versus both, and shorter studies. Conclusion. These findings provide important information for researchers and practitioners with respect to exercise programs targeting BMD in adults.

Bone ultrasound and physical activity in postmenopausal Spanish women

We studied the effects of moderate physical activity on bone mass in healthy postmenopausal women as assessed by quantitative bone ultrasound. We enrolled a total of 326 postmenopausal women (60.95 ± 8.51 years old and 13.02 ± 9.52 years since menopause) and categorized them by weekly physical activity in their leisure time (sedentary, moderate, and active). We administered a questionnaire on general health and diet and measured bone density by ultrasound on phalanges II-V in the nondominant hand. We found no significant difference in the amplitude-dependent speed of sound (Ad-SoS; p > .05) between sedentary and active women. We concluded that the changes induced by moderate physical activity on bone mass are minimal in healthy postmenopausal women.

The beneficial effect of leisure-time physical activity on bone mineral density in pre- and postmenopausal women

Regular exercise and physical activity (PA) are known to be protective factors for maintaining bone mineral density (BMD) and preventing osteoporotic fracture. We investigated the associations between leisure-time PA and BMD in 2,903 premenopausal and 2,267 postmenopausal women in Korea. BMDs of the lumbar spine and femur were measured using dual-energy X-ray absorptiometry. Leisure-time PA levels were assessed by a self-administrated questionnaire, and a total metabolic equivalent (MET) score was obtained. Regardless of menopausal status, performing more than moderate levels of leisure-time PA or total MET score had a significant positive association with BMD at both the lumbar spine and femur. In the premenopausal group, women whose total MET score was 1,050-1,500 (MET-min/week) appeared to have the highest lumbar spine and femoral BMD (p < 0.001). The associations between PA level and lumbar spine and femoral BMD were also shown in the postmenopausal group (p < 0.001). In addition, we found dose-response relationships between increasing exercise level and femoral BMD in both the premenopausal and postmenopausal groups. Our results indicate that a more than moderate level of leisure-time PA plays a role in maintaining BMD.

Physical activity and health during the menopausal transition

The benefits of regular physical activity are well established, but evidence for a protective effect against the adverse health consequences accompanying the menopausal transition is limited. This article reviews that evidence, concluding that more physical activity is generally associated with fewer somatic and mood symptoms. Physical activity seems to minimize weight gain and changes in body composition and fat distribution experienced at midlife and might attenuate the rapid bone density loss that occurs. Given these benefits, clinicians treating perimenopausal women should encourage their patients to follow guidelines for physical activity (≥150 minutes a week of moderate-intensity activity).

A meta-analysis of brief high-impact exercises for enhancing bone health in premenopausal women

A snapshot of current evidence from 6 randomised controlled trials for the effects of short bouts of high-impact exercises in 256 women via meta-analysis reveals that ample osteogenic response could be realised at the femoral neck and trochanter of premenopausal women with rest-inserted bouts of few mechanical bone loading cycles.

INTRODUCTION

Exercise is an important means of improving bone health and preventing osteoporosis. Brief bouts of simple exercises may be useful for aiding lifestyle compliance to physical activity. This study aimed to review the evidence on the effect of brief, high-impact exercise on bone health among premenopausal women.

METHODS

A structured and comprehensive search of databases was undertaken along with hand searching of key journals and reference lists to locate relevant studies published and unpublished up to January 2011. Six randomised controlled trials met predetermined inclusion criteria. Brief high-impact exercises (<30 min) were examined for their effect on bone mineral density (BMD) among premenopausal women. Trial quality was assessed using the Effective Public Health Practice Project quality assessment tool. Study outcomes for analysis, absolute change (grams per square centimetre) or relative change (in percent) in BMD at femoral neck, trochanter and lumbar spine were compared by calculating standardised mean difference (SMD) using fixed- and random effects models.

RESULTS

Quality of included trials varied from medium to high on a scale of 1 to 3. Brief bouts of exercise led to significant increases in femoral neck BMD (SMD = 0.64, 95% confidence interval (CI) = 0.38, 0.90, overall effect Z value = 4.84, p = 0.001); a modest increase in trochanteric BMD (SMD = 0.36, 95% CI = 0.10, 0.61, Z value = 2.08, p = 0.04) and no increase in spinal BMD (SMD = 0.04, 95% CI= -0.23, 0.31, Z value = 0.26, p = 0.79).

CONCLUSION

Based on the meta-analysis, brief high-impact exercise improves BMD at the hip but not at the lumbar spine. Effectiveness of this form of exercise as a lifestyle physical activity for prevention of osteoporosis should be explored in larger populations.

Obstacles in the optimization of bone health outcomes in the female athlete triad

Maintaining low body weight for the sake of performance and aesthetic purposes is a common feature among young girls and women who exercise on a regular basis, including elite, college and high-school athletes, members of fitness centres, and recreational exercisers. High energy expenditure without adequate compensation in energy intake leads to an energy deficiency, which may ultimately affect reproductive function and bone health. The combination of low energy availability, menstrual disturbances and low bone mineral density is referred to as the 'female athlete triad'. Not all athletes seek medical assistance in response to the absence of menstruation for 3 or more months as some believe that long-term amenorrhoea is not harmful. Indeed, many women may not seek medical attention until they sustain a stress fracture. This review investigates current issues, controversies and strategies in the clinical management of bone health concerns related to the female athlete triad. Current recommendations focus on either increasing energy intake or decreasing energy expenditure, as this approach remains the most efficient strategy to prevent further bone health complications. However, convincing the athlete to increase energy availability can be extremely challenging. Oral contraceptive therapy seems to be a common strategy chosen by many physicians to address bone health issues in young women with amenorrhoea, although there is little evidence that this strategy improves bone mineral density in this population. Assessment of bone health itself is difficult due to the limitations of dual-energy X-ray absorptiometry (DXA) to estimate bone strength. Understanding how bone strength is affected by low energy availability, weight gain and resumption of menses requires further investigations using 3-dimensional bone imaging techniques in order to improve the clinical management of the female athlete triad.

Sex differences in resting hemodynamics and arterial stiffness following 4 weeks of resistance versus aerobic exercise training in individuals with pre-hypertension to stage 1 hypertension

Background

Hypertension (HTN) exhibits sexual dimorphism; the incidence for women surpasses men during the sixth decade of life, while the pharmacological treatments are less effective and produce more side-effects in women than in men. Aerobic exercise (AE) has been shown to prevent and treat HTN; however, resistance exercise (RE) is not recommended as a strategy to treat HTN. In this study, we investigated the potential sex differences of AE versus RE in a cohort of unmedicated patients with hypertension.

Methods

In total, 40 moderately active, pre-hypertensive or stage 1 essential hypertensive male (M) and female (F) participants aged 40 to 60 years were randomly divided into four groups: M AE, M RE, F AE, and F. Each group exercised at moderate intensity, 3 days/week for 4 weeks. Hemodynamic, vascular and blood-flow data were collected before and after exercise training.

Results

Men showed a significant increase in central pulse wave velocity following RE while females showed no significant changes (12 ± to 13.9 ± vs. 9.2 ± to 9.6 ± m/s, respectively). RE showed significantly greater increases in peak blood flow when compared to AE (F RE 15 ± to 20 ± vs. F AE 17.5 ± to19.5 ±, M RE 19 ± to 24 ± vs M AE 21 ± to 25 ± ml* 100 ml*min, respectively). In addition, systolic and diastolic BP decreased greater for women following RE when compared to AE whereas men showed comparable decreases in BP following either exercise mode.

Conclusion

Moderate-intensity RE training may be a more favorable for women as a treatment option for hypertension because of greater decreases in diastolic BP and significant increases in flow-mediated dilation without concomitant increases in arterial stiffness, compared with their male counterparts.

Exercise for preventing and treating osteoporosis in postmenopausal women

BACKGROUND

Osteoporosis is a condition resulting in an increased risk of skeletal fractures due to a reduction in the density of bone tissue. Treatment of osteoporosis typically involves the use of pharmacological agents. In general it is thought that disuse (prolonged periods of inactivity) and unloading of the skeleton promotes reduced bone mass, whereas mechanical loading through exercise increases bone mass.

OBJECTIVES

To examine the effectiveness of exercise interventions in preventing bone loss and fractures in postmenopausal women.

SEARCH STRATEGY

During the update of this review we updated the original search strategy by searching up to December 2010 the following electronic databases: the Cochrane Musculoskeletal Group's Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2010 Issue 12); MEDLINE; EMBASE; HealthSTAR; Sports Discus; CINAHL; PEDro; Web of Science; Controlled Clinical Trials; and AMED. We attempted to identify other studies by contacting experts, searching reference lists and searching trial registers.

SELECTION CRITERIA

All randomised controlled trials (RCTs) that met our predetermined inclusion criteria.

DATA COLLECTION AND ANALYSIS

Pairs of members of the review team extracted the data and assessed trial quality using predetermined forms. For dichotomous outcomes (fractures), we calculated risk ratios (RRs) using a fixed-effect model. For continuous data, we calculated mean differences (MDs) of the percentage change from baseline. Where heterogeneity existed (determined by the I(2) statistic), we used a random-effects model.

MAIN RESULTS

Forty-three RCTs (27 new in this update) with 4320 participants met the inclusion criteria. The most effective type of exercise intervention on bone mineral density (BMD) for the neck of femur appears to be non-weight bearing high force exercise such as progressive resistance strength training for the lower limbs (MD 1.03; 95% confidence interval (CI) 0.24 to 1.82). The most effective intervention for BMD at the spine was combination exercise programmes (MD 3.22; 95% CI 1.80 to 4.64) compared with control groups. Fractures and falls were reported as adverse events in some studies. There was no effect on numbers of fractures (odds ratio (OR) 0.61; 95% CI 0.23 to 1.64). Overall, the quality of the reporting of studies in the meta-analyses was low, in particular in the areas of sequence generation, allocation concealment, blinding and loss to follow-up.

AUTHORS' CONCLUSIONS

Our results suggest a relatively small statistically significant, but possibly important, effect of exercise on bone density compared with control groups. Exercise has the potential to be a safe and effective way to avert bone loss in postmenopausal women.

Exercise beyond menopause: Dos and Don'ts

With a significant number of women belonging to the status of menopause and beyond, it is imperative to plan a comprehensive health program for them, including lifestyle modifications. Exercise is an integral part of the strategy. The benefits are many, most important being maintenance of muscle mass and thereby the bone mass and strength. The exercise program for postmenopausal women should include the endurance exercise (aerobic), strength exercise and balance exercise; it should aim for two hours and 30 minutes of moderate aerobic activity each week. Every woman should be aware of her target heart rate range and should track the intensity of exercise employing the talk test. Other deep breathing, yoga and stretching exercises can help to manage the stress of life and menopause-related symptoms. Exercises for women with osteoporosis should not include high impact aerobics or activities in which a fall is likely. The women and the treating medical practitioner should also be aware of the warning symptoms and contraindications regarding exercise prescription in women beyond menopause. The role of exercise in hot flashes, however, remains inconclusive. Overall, exercising beyond menopause is the only noncontroversial and beneficial aspect of lifestyle modification and must be opted by all.

Effects of physical activity on bone remodeling

Physical exercise is recommended to improve bone mass in growing children and decrease bone loss in elderly men and women. However, the specific mechanisms by which exercise influences bone metabolism are still not thoroughly understood. The effect of physical activity on the skeleton is generally evaluated by dual-energy x-ray absorptiometry, which measures bone mineral density. However, a relatively long period is needed to detect even a minor variation in bone mineral density with this technique, limiting its usefulness. Bone biochemical markers that reflect the cellular activities of bone formation and resorption are thus also useful tools, both to monitor the acute effects of exercise on bone remodeling and to investigate the mechanisms of exercise-induced changes in bone mass. This article describes the effects of physical activity on bone remodeling in various types of population. The comparison of sedentary individuals and athletes with many years of high-volume sports practice, for example, has clarified some of the long-term effects of exercise. Moreover, the acute variation in bone cell activities after brief exercise or a training program is here examined. The interpretation of results is difficult, however, because of the many parameters, such as age, that are involved. The various populations are therefore categorized to reflect the biological factors implicated in the modulation of bone marker response during exercise.

Intervening on the side effects of hormone-dependent cancer treatment: the role of strength training

While prostate and breast cancers are both highly prevalent and treatable using hormone suppression therapy, a constellation of side effects ensue, which mimic typical aging effects but at an accelerated pace. Because strength training is considered to be an intervention of choice for addressing the musculoskeletal and metabolic consequences of normal aging in older adults, it may be an effective intervention to attenuate or reverse the side effects of hormone-dependent cancer treatment. This paper provides an overview of the independent effects of strength training on common musculoskeletal and metabolic side effects of hormone-dependent therapy used for prostate and breast cancers. Strength training appears to be an effective complementary therapy for some of the adverse effects of prostate and breast treatment. Future research needs to address potential mechanisms to explain recent findings and to explore the role of strength training in addressing specific risk factors resulting from cancer treatment.

Nullius in verba: a call for the incorporation of evidence-based practice into the discipline of exercise science

Evidence-based practice (EBP) is a concept that was popularized in the early 1990s by several physicians who recognized that medical practice should be based on the best and most current available evidence. Although this concept seems self-evident, much of medical practice was based on outdated textbooks and oral tradition passed down in medical school. Currently, exercise science is in a similar situation. Due to a lack of regulation within the exercise community, the discipline of exercise science is particularly prone to bias and misinformation, as evidenced by the plethora of available programmes with efficacy supported by anecdote alone. In this review, we provide a description of the five steps in EBP: (i) develop a question; (ii) find evidence; (iii) evaluate the evidence; (iv) incorporate evidence into practice; and (v) re-evaluate the evidence. Although objections have been raised to the EBP process, we believe that its incorporation into exercise science will improve the credibility of our discipline and will keep exercise practitioners and academics on the cutting edge of the most current research findings.

Effects of a 1-year randomized controlled trial of resistance training on lower limb bone and muscle structure and function in older men

SUMMARY

A 1-year randomized controlled trial of resistance training compared with a control group was undertaken in 143 men aged 55-80 years. Although hip bone mineral density, lean body mass, and function increased in both groups, lean body mass and function but not bone density increased more in the resistance group.

INTRODUCTION

Previous studies have demonstrated a positive effect of resistance training on bone mineral density (BMD) in postmenopausal women, but the effect in men is unclear. The aim was to examine the effect of a 1-year resistance training program on bone and lean body mass in 143 men aged 55-80 years, randomized to either resistance training or active control.

METHODS

Resistance exercises were selected to provide loading at the hips. Measurements were taken at 0, 6, and 12 months for BMD (whole body, hip, and spine), lean body mass, strength, and functional fitness.

RESULTS

The intervention showed a significant increase in total hip BMD for both groups at 12 months (active control, 1,014-1,050 mg/cm(2); resistance, 1,045-1,054 mg/cm(2), p < 0.05) with no increased effect of resistance training compared to active control. However, compared to the active control group, the resistance group increased their lean body mass (active control, 0.1 +/- 2.1%; resistance, 1.5 +/- 2.7%, p < 0.05), fitness (active control, 4.6 +/- 11.1%; resistance, 13.0 +/- 13.4%, p < 0.05), and lower limb muscle strength (active control, 14.3 +/- 16.8%; resistance, 39.4 +/- 30.87%, p < 0.05).

CONCLUSIONS

In contrast to previous findings in older women, in older men, a resistance training program does not increase hip bone mass more than walking 30 min three times a week.

Association of physical exercise and calcium intake with bone mass measured by quantitative ultrasound

Background

Interventions other than medications in the management of osteoporosis are often overlooked. The purpose of this study was to investigate the association of physical activity and calcium intake with bone parameters.

Methods

We measured the heel T-score and stiffness index (SI) in 1890 pre- and postmenopausal women by quantitative ultrasound (QUS) and assessed physical activity and dietary calcium intake by questionnaire. Participants were divided according to their weekly physical activity (sedentary, moderately active, systematically active) and daily calcium consumption (greater than or less than 800 mg/day).

Results

SI values were significantly different among premenopausal groups (p = 0.016) and between sedentary and systematically active postmenopausal women (p = 0.039). QUS T-scores in systematically active premenopausal women with daily calcium intake > 800 mg/day were significantly higher than those in all other activity groups (p < 0.05) independent of calcium consumption.

Conclusions

Systematic physical activity and adequate dietary calcium intake are indicated for women as a means to maximize bone status benefits.

Time-course of exercise and its association with 12-month bone changes

Background

Exercise has been shown to have positive effects on bone density and strength. However, knowledge of the time-course of exercise and bone changes is scarce due to lack of methods to quantify and qualify daily physical activity in long-term. The aim was to evaluate the association between exercise intensity at 3, 6 and 12 month intervals and 12-month changes in upper femur areal bone mineral density (aBMD) and mid-femur geometry in healthy premenopausal women.

Methods

Physical activity was continuously assessed with a waist-worn accelerometer in 35 healthy women (35-40 years) participating in progressive high-impact training. To describe exercise intensity, individual average daily numbers of impacts were calculated at five acceleration levels (range 0.3-9.2 g) during time intervals of 0-3, 0-6, and 0-12 months. Proximal femur aBMD was measured with dual x-ray absorptiometry and mid-femur geometry was evaluated with quantitative computed tomography at the baseline and after 12 months. Physical activity data were correlated with yearly changes in bone density and geometry, and adjusted for confounding factors and impacts at later months of the trial using multivariate analysis.

Results

Femoral neck aBMD changes were significantly correlated with 6 and 12 months' impact activity at high intensity levels (> 3.9 g, r being up to 0.42). Trochanteric aBMD changes were associated even with first three months of exercise exceeding 1.1 g (r = 0.39-0.59, p < 0.05). Similarly, mid-femoral cortical bone geometry changes were related to even first three months' activity (r = 0.38-0.52, p < 0.05). In multivariate analysis, 0-3 months' activity did not correlate with bone change at any site after adjusting for impacts at later months. Instead, 0-6 months' impacts were significant correlates of 12-month changes in femoral neck and trochanter aBMD, mid-femur bone circumference and cortical bone attenuation even after adjustment. No significant correlations were found at the proximal or distal tibia.

Conclusion

The number of high acceleration impacts during 6 months of training was positively associated with 12-month bone changes at the femoral neck, trochanter and mid-femur. These results can be utilized when designing feasible training programs to prevent bone loss in premenopausal women.

Trial registration

Clinical trials.gov NCT00697957

Progressive resistance strength training for improving physical function in older adults

BACKGROUND

Muscle weakness in old age is associated with physical function decline. Progressive resistance strength training (PRT) exercises are designed to increase strength.

OBJECTIVES

To assess the effects of PRT on older people and identify adverse events.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialized Register (to March 2007), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2007, Issue 2), MEDLINE (1966 to May 01, 2008), EMBASE (1980 to February 06 2007), CINAHL (1982 to July 01 2007) and two other electronic databases. We also searched reference lists of articles, reviewed conference abstracts and contacted authors.

SELECTION CRITERIA

Randomised controlled trials reporting physical outcomes of PRT for older people were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trial quality and extracted data. Data were pooled where appropriate.

MAIN RESULTS

One hundred and twenty one trials with 6700 participants were included. In most trials, PRT was performed two to three times per week and at a high intensity. PRT resulted in a small but significant improvement in physical ability (33 trials, 2172 participants; SMD 0.14, 95% CI 0.05 to 0.22). Functional limitation measures also showed improvements: e.g. there was a modest improvement in gait speed (24 trials, 1179 participants, MD 0.08 m/s, 95% CI 0.04 to 0.12); and a moderate to large effect for getting out of a chair (11 trials, 384 participants, SMD -0.94, 95% CI -1.49 to -0.38). PRT had a large positive effect on muscle strength (73 trials, 3059 participants, SMD 0.84, 95% CI 0.67 to 1.00). Participants with osteoarthritis reported a reduction in pain following PRT(6 trials, 503 participants, SMD -0.30, 95% CI -0.48 to -0.13). There was no evidence from 10 other trials (587 participants) that PRT had an effect on bodily pain. Adverse events were poorly recorded but adverse events related to musculoskeletal complaints, such as joint pain and muscle soreness, were reported in many of the studies that prospectively defined and monitored these events. Serious adverse events were rare, and no serious events were reported to be directly related to the exercise programme.

AUTHORS' CONCLUSIONS

This review provides evidence that PRT is an effective intervention for improving physical functioning in older people, including improving strength and the performance of some simple and complex activities. However, some caution is needed with transferring these exercises for use with clinical populations because adverse events are not adequately reported.

Osteoporosis and Strength Training

Osteoporosis is a major public health problem. Mechanical strain, imparted by muscle action and ground reaction forces, regulates bone size, shape, mineral mass, and density and subsequently bone strength. Thus, physical activity is critical for bone development, bone health, and fracture risk reduction. Animal studies, in which strain can be manipulated and measured directly, consistently show bone responds to high-strain magnitudes and rates, and only a few repetitions are needed to elicit a response. Extrapolation to humans suggests resistance exercise may be effective for osteoporosis prevention. Indeed, strength-trained athletes have significantly higher bone mass and density than athletes and nonathletes who do not engage in similar training. Prospective studies also support the benefits of resistance exercise demonstrating slowed bone loss and often an increase of 1% to 3% in regional bone mineral density, especially in women. Although more work is needed to define the optimal dose and the effects of nonmechanical factors (eg, nutritional, endocrine, body composition) on the response, the effects of resistance exercise on muscle mass and strength, balance, and agility, in addition to direct skeletal benefits, underscore its importance for osteoporosis, falls, and fracture prevention.