Concentric and eccentric isokinetic resistance training similarly increases muscular strength, fat-free soft tissue mass, and specific bone mineral measurements in young women

Lean Body Mass, Muscle Architecture and Powerlifting Performance during Preseason and in Competition

Lean body mass (LBM) is correlated with powerlifting performance in athletes competing in different bodyweight classes. However, it remains unknown whether changes in LBM are correlated with performance changes in powerlifters preparing for a competition. The aim of this study was to investigate the changes in LBM and performance in powerlifters preparing for a competition. Eight male powerlifters (age 31.7 ± 9.8 years, height 1.77 ± 0.06 m, weight 99.2 ± 14.6 kg) and three female powerlifters (age 32.7 ± 16.3 years, height 1.54 ± 0.06 m, weight 66.6 ± 20.9 kg) participated in the study. The athletes followed individualized periodized training programs for 12 weeks, aiming to maximize their performance for the national championship. The maximum strength (1-RM) in the squat, bench press, and deadlift, body composition, handgrip strength, anaerobic power, quadriceps' cross-sectional area and vastus lateralis muscle architecture were measured before and after the training period. Significant increases were found after the training period in the squat (5.8 ± 7.0%, p < 0.05), bench press (4.9 ± 9.8%, p = 0.05) and deadlift (8.3 ± 16.7%, p < 0.05). Significant correlations were found between the 1-RM and LBM before and after the training period (r > 0.75, p < 0.05). The changes in the 1-RM after the training intervention correlated with the changes in the total LBM (p < 0.05). These results suggest that individual changes in LBM due to systematic resistance training for a competition may dictate increases in the 1-RM strength in powerlifters.

High-Protein Diets during either Resistance or Concurrent Training Have No Detrimental Effect on Bone Parameters in Resistance-Trained Males

BACKGROUND

The effects of combining resistance training (RT) and concurrent training (CT; resistance + endurance training) with varied protein doses on bone measures remain poorly understood. Hence, we conducted a comparison of the impacts of two high-protein diets (1.6 or 3.2 g kg-1 d-1) over 16 weeks in resistance-trained males, either with CT or RT alone.

METHODS

A total of forty-eight males, all of whom were resistance-trained, had the following demographics: 26.6 ± 6 years, body mass index: 25.6 ± 2.9 kg m-2 administered either 3.2 g kg-1 d-1 protein (CT2; n = 12; RT2; n = 12) or 1.6 g kg-1 d-1 protein (CT1; n = 12; RT1; n = 12) during 16 weeks (four sessions·w-1). Bone parameters were assessed pre- and post-intervention.

RESULTS

There was no significant interaction between the intervention group and time for the legs, arms, ribs, or pelvis area BMC and BMD (p > 0.05). For the BMD of the pelvis and the BMC of the right ribs, however, there were significant time effects noted (p < 0.05). Furthermore, there was a significant interaction between the intervention group and time in the lumbar and thoracic spines, with a particular time effect noted for the thoracic spine region (p < 0.05). The regional differences in skeletal responses to the intervention are highlighted by these data.

CONCLUSION

Our findings show that the intake of two high-protein diets combined with RT and CT during 16 weeks had no adverse effects on bone tissue parameters. While these findings indicate that protein intake between 2 and 3 times the current RDI does not promote bone demineralization when consumed in conjunction with exercise, future studies investigating the long-term effects of chronic high protein intake on bone tissue health are warranted.

Association between segmental body composition and bone mineral density in US adults: results from the NHANES (2011-2018)

OBJECTIVE

The association between segmental body composition and bone mineral density (BMD) remains uncertain. The primary aim of this cross-sectional investigation was to elucidate the connection between segmental body composition and BMD within the United States adult population.

METHODS

We selected a cohort of 10,096 individuals from the National Health and Nutrition Examination Survey (NHANES) database, with a mean age of 39 years and a mean BMI of 28.5 kg/m². The parameter of segmental body composition was achieved by quantifying body fat and lean mass percentages across various anatomical regions, including the torso, Android, Gynoid, arms and legs. We conducted a weighted multivariate linear regression analysis to investigate the association between segmental body composition and total BMD. Additionally, subgroup analysis was performed based on age and gender.

RESULTS

We found an inverse association between fat proportion in each anatomical region and total BMD, with the arm and leg regions demonstrating the most significant negative correlation. Conversely, a positive correlation was observed between lean mass and BMD across all anatomical regions. These associations remained consistent in subgroup analyses.

CONCLUSION

Our investigation revealed a negative association between adipose levels in various anatomical regions and BMD among Americans aged 20 to 59. Importantly, higher fat proportion in the extremities exerted the most deleterious impact on BMD. Furthermore, an increase in lean mass within each anatomical region was ascertained to confer a positive effect on bone health. Consequently, the evaluation of segmental body composition is well-positioned to predict bone health status.

Skeletal effects of eccentric strengthening exercise: a scoping review

BACKGROUND

Conventional progressive concentric strengthening exercise (CSE) to improve bone mineral density (BMD) and bone mineral content (BMC) may not be feasible for populations with chronic musculoskeletal and/or metabolic conditions, such as osteoporosis or obesity. Muscle lengthening exercise, also known as an eccentric strengthening exercise (ESE), may have a special utility for those populations due to greater force generation versus CSE. In fact, greater mechanical loading can be induced on bone at lower resistance levels with ESE. However, effects of ESE on BMD and BMC are unclear. Thus, the purpose of this review was to interrogate the effects of ESE on BMD and BMC.

METHODS

A literature review was conducted between January 1995 and April 2022 focusing on randomized controlled trials investigating the effects of ESE on BMD and/or BMC in humans. Terms covering the domains of exercise, bone, and populations were searched on PubMed, CINAHL, and Scopus. The methodological quality of each interventional study was rated using Physiotherapy Evidence Database (PEDro) scale. Cohen's d was calculated to determine the magnitude of the effects of ERE on site-specific outcome measures of BMD and/or BMC.

RESULTS

Out of 1,182 articles initially found, a total of seven full length articles met our inclusion criteria. Of the seven studies, most of the interventions were performed in young (n = 5, PEDro = 5-7) versus middle-aged (n = 1, PEDro = 4) or older (n = 1, PEDro = 6) adults. BMD and BMC generally improved due to ESE; however the effects of ESE on BMD and BMC were non-homogenous. Effect size (d) ranged from 0.10-0.87 in young adults while it was 1.16 in older adults. Effect size (d) could not be calculated for the middle-aged adult study due to critical methodological limitations of the intervention.

CONCLUSIONS

Large variability exists for the effectiveness of ESE on BMD/BMC across the human life spectrum. The benefits of ESE on BMD holds promise but rigorous studies are lacking. Further research is needed to examine if the dose, mode, age, and sex-specificity dictate effects of ESE on BMD/BMC.

The Health and Functional Benefits of Eccentric versus Concentric Exercise Training: A Systematic Review and Meta-Analysis

This review compared the effects of eccentric versus concentric exercise training in healthy people and people with metabolic disease. A systematic search on Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, SPORTDiscus, Web of Science, SCOPUS and PubMed was conducted in February 2022. Randomised controlled trials conducted on sedentary healthy adults or those with an existing metabolic disease that compared eccentric versus concentric exercise training interventions of four weeks or longer that involved multiple joints and large muscle groups (e.g., walking, whole-body resistance training) were included in the review. The primary outcome was glucose handling, measured as HbA1c, HOMA, fasting glucose or insulin. Measures of cardiovascular health, muscle strength, and functional physical fitness were secondary outcomes. Nineteen trials involving 618 people were included. Results of meta-analyses showed that eccentric exercise had no benefit to glucose handling (HbA1c level; SMD - 0.99; 95% CI, -2.96 to 0.98; n = 74; P = 0.32) but resulted in significant increases in overall muscle strength (SMD 0.70; 95% CI 0.25 to 1.15; n = 224; P = 0.003) and decreases in blood pressure (Systolic Blood Pressure; MD -6.84; 95% CI, -9.84 to -3.84; n = 47, P = 0.00001, and Diastolic Blood Pressure; MD -6.39; 95% CI -9.62 to -3.15; n = 47, P = 0.0001). Eccentric exercise is effective for improving strength and some markers of cardiovascular health compared to traditional exercise modalities. Additional high-quality studies are necessary to validate these results. (PROSPERO registration: CRD42021232167).

May the Force and Mass Be With You-Evidence-Based Contribution of Mechano-Biological Descriptors of Resistance Exercise

Skeletal muscle is one of the most important tissues of the human body. It comprises up to 40% of the body mass and is crucial to survival. Hence, the maintenance of skeletal muscle mass and strength is pivotal. It is well-established that resistance exercise provides a potent anabolic stimulus to increase muscle mass and strength in men and women of all ages. Resistance exercise consists of mechano-biological descriptors, such as load, muscle action, number of repetitions, repetition duration, number of sets, rest interval between sets, frequency, volitional muscular failure, and range of motion, which can be manipulated. Herein, we discuss the evidence-based contribution of these mechano-biological descriptors to muscle mass and strength.

Impact of strength training on bone mineral density in HIV-positive patients

Abstract Introduction: Highly active antiretroviral therapy (HAART) transformed HIV from a fatal disease to a chronic one, but it has adverse effects, such as the lipodystrophy syndrome, characterized by morphological and metabolic changes, such as reduced bone mineral density (BMD), potentiating morbidities and mortality. Strength training (ST) aims to increase BMD, due to the osteogenic effect. Objective: To verify the impact of strength training on BMD in people with HIV. Methods: This is a quasi-experimental study, which included 40 people with a mean age of 50 ± 6 years, separated into trained group (TG, n = 20) and control group (CG, n = 20), with reduction in BMD, HIV-positive, using HAART and without exercising. BMD was assessed by DEXA in the lumbar spine, femoral neck and distal 1/3 of the radius, before and after 12 weeks, with the GT submitted to 36 ST and the CG without physical training in the DEXA evaluation in the same time interval. Results: TG had a significant increase with great effect on BMD in all segments: lumbar spine (p = 0.001; ES: 1.87), femoral neck (p = 0.003; ES: 2.20) and 1/3 distal of the radius (p = 0.001; ES: 1.81). Meanwhile, CG group showed a significant reduction with great effect on the femoral neck (p = 0.020; ES: 2.56) and 1/3 distal of the radius (p = 0.015; ES: 2.93), while the lumbar spine showed a great effect to reduce BMD (p = 0.293; ES: 1.78). Conclusion: ST can be used as a therapeutic resource to increase BMD in people with HIV, contributing to the advancement in the search for non-drug therapeutic practices.

Can Exercise-Induced Muscle Damage Be a Good Model for the Investigation of the Anti-Inflammatory Properties of Diet in Humans?

Subclinical, low-grade, inflammation is one of the main pathophysiological mechanisms underlying the majority of chronic and non-communicable diseases. Several methodological approaches have been applied for the assessment of the anti-inflammatory properties of nutrition, however, their impact in human body remains uncertain, because of the fact that the majority of the studies reporting anti-inflammatory effect of dietary patterns, have been performed under laboratory settings and/or in animal models. Thus, the extrapolation of these results to humans is risky. It is therefore obvious that the development of an inflammatory model in humans, by which we could induce inflammatory responses to humans in a regulated, specific, and non-harmful way, could greatly facilitate the estimation of the anti-inflammatory properties of diet in a more physiological way and mechanistically relevant way. We believe that exercise-induced muscle damage (EIMD) could serve as such a model, either in studies investigating the homeostatic responses of individuals under inflammatory stimuli or for the estimation of the anti-inflammatory or pro-inflammatory potential of dietary patterns, foods, supplements, nutrients, or phytochemicals. Thus, in this review we discuss the possibility of exercise-induced muscle damage being an inflammation model suitable for the assessment of the anti-inflammatory properties of diet in humans.

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.

WOMEN’S FEMORAL MASS CONTENT CORRELATES TO MUSCLE STRENGTH INDEPENDENTLY OF LEAN BODY MASS

ABSTRACT Introduction There is limited consensus regarding the recommendation of the most effective form of exercise for bone integrity, despite the fact that weight training exercise promotes an increase in muscle mass and strength as recurrent responses. However, strength variations in women do not depend on muscle mass development as they do in men, but strength enhancement has shown the potential to alter bone mineral content (BMC) for both sexes. Objective This study analyzed the potential of muscle strength, as well as that of whole-body and regional body composition, to associate femoral BMC in young women. Methods Fifteen female college students (aged 24.9 ± 7.2 years) were assessed for regional and whole-body composition using dual-energy X-ray absorptiometry (DXA). Maximum muscle strength was assessed by the one-repetition maximum (1RM) test in the following exercises: bench press (BP), lat pulldown (LP), knee flexion (KF), knee extension (KE) and 45° leg press (45LP). Linear regression analyzed BMC relationships with regional composition and 1RM values. Dispersion and error measures (R 2 aj and SEE), were tested, defining p ≤0.05. Results Among body composition variables, only total lean body mass was associated with femoral BMC values (R 2 aj = 0.37, SEE = 21.3 g). Regarding strength values, 1RM presented determination potential on femoral BMC in the CE exercise (R 2 aj = 0.46, SEE = 21.3 g). Conclusions Muscle strength aptitude in exercises for femoral regions is relevant to the femoral mineralization status, having associative potential that is similar to and independent of whole-body lean mass. Therefore, training routines to increase muscle strength in the femoral region are recommended. In addition, increasing muscle strength in different parts of the body may augment bone remodeling stimulus, since it can effectively alter total whole-body lean mass. Level of Evidence II; Development of diagnostic criteria in consecutive patients (with universally applied reference ‘‘gold’’ standard).

Effect of 7 Months of Physical Training and Military Routine on the Bone Mass of Young Adults

INTRODUCTION

Physical activity (PA) has a great influence on bone mineral density (BMD) and bone mineral content (BMC), however longitudinal studies that seek to relate bone mass to physical activity are scarce and have a small sample size. The aim of this study was to evaluate and compare the effect of 7 months of military physical training (MPT), impact sports (IS), and swimming in the bone mass of young military adults.

MATERIALS AND METHODS

A prospective study was conducted with 213 military school students (male and aged 19.2 ± 1.2 years) divided into three groups: MPT (n = 144), IS (n = 56), and Swimming (n = 13). Dual-energy X-ray absorptiometry was used to determine body composition (percentage of fat, fat mass, and fat-free mass) and bone mass (BMD, BMD Z-Score, total BMC, arm BMC, leg BMC, and trunk BMC), at the beginning of the military service and after 7 months of training.

RESULTS

It was observed a significant increase in BMD, BMD Z-Score, total BMC and BMC of all segments analyzed for all groups (p < 0.01). There was a significantly greater variation in BMD of the IS group in relation to the MPT group (p < 0.01), and in the arm BMC of the MPT group in relation to the IS group (p < 0.05).

CONCLUSION

After 7 months of training, there were significant increases in BMC and BMD of all the groups evaluated. The bone response was associated with the muscular group used in the physical exercise and the IS group showed greater gain in BMD.

BONE HEALTH, MUSCLE STRENGTH AND LEAN MASS: RELATIONSHIPS AND EXERCISE RECOMMENDATIONS

ABSTRACT Although muscle strength, lean mass and bone mineral content/density (BMC/BMD) are consistently reported as major outcomes of resistance training (RT), there is still no agreement on the RT regimen that is capable of achieving this result in men and women of different ages. This study describes the effects of RT on muscle strength, lean mass and bone mineralization, highlighting the relationships between them and analyzing the effectiveness of the RT protocol. Information searches were conducted in open access online academic libraries, using the BMC/BMD indices combined with muscle strength, body composition, and resistance exercises. The results showed changes in BMC/BMD in 72% of the studies published in the last decade. Among these, 77% recommended loads ≥ 80% 1-RM, 61% involved older individuals (> 60 years) and 61% had planning protocols of between 3 and 5 months (~12-20 weeks). The results also highlight muscle strength as a promising index of variations in BMC/BMD, with a moderate to high level of association (r2>0.5), which are specific for men and women in relation to the body region with best responsiveness. Among the studies published in last decade, about 61% had protocols involving only RT, and of these, 82% observed combined changes in BMC/BMD, body composition and muscle strength. This review therefore concludes that RT is important for improving muscle strength, increasing lean mass (whole-body and regional) and preventing risk factors that could impair the mineral integrity of the bone tissue, in individuals of all ages and sexes. Level of Evidence I; Systematic review of Level I RCTs (and study results were homogenous).

The effects of resistance training on bone mineral density and bone quality in type 2 diabetic rats

Resistance training (RT) has been known to be effective in maintaining and improving bone strength, which is based on bone mineral density (BMD) and bone quality. However, it is not clear whether RT is effective in improving bone strength in patients with type-2 diabetes mellitus (T2DM), who have a high risk of fracture. Therefore, we tested the effects of a 6-week RT regimen using percutaneous electrical stimulation in T2DM model rats, male Otsuka Long-Evans Tokushima Fatty (OLETF), and its control, Long-Evans Tokushima Otsuka (LETO). After 6 weeks of RT, tibial BMD in RT legs was significantly higher than that in control (CON) legs in both groups. In diaphyseal cortical bone, bone area/tissue area, and cortical thickness was significantly increased in RT legs compared with CON legs in both groups. Cortical porosity was highly observed in OLETF compared with LETO, but RT improved cortical porosity in both groups. Interestingly, trabecular number, trabecular thickness and trabecular space as well as BMD and bone volume/tissue volume in proximal tibial metaphyseal trabecular bone were significantly improved in RT legs compared with CON legs in both groups. In contrast, connectivity density and structural model index were not affected by RT. These results indicate that the 6-week RT regimen effectively increased BMD and improved bone quality in T2DM model rats as well as control rats. Therefore, RT may have the potential to improve bone strength and reduce fracture risk, even in patients with T2DM.

Chronic Adaptations to Eccentric Training: A Systematic Review

BACKGROUND

Resistance training is an integral component of physical preparation for athletes. A growing body of evidence indicates that eccentric strength training methods induce novel stimuli for neuromuscular adaptations.

OBJECTIVE

The purpose of this systematic review was to determine the effects of eccentric training in comparison to concentric-only or traditional (i.e. constrained by concentric strength) resistance training.

METHODS

Searches were performed using the electronic databases MEDLINE via EBSCO, PubMed and SPORTDiscus via EBSCO. Full journal articles investigating the long-term (≥4 weeks) effects of eccentric training in healthy (absence of injury or illness during the 4 weeks preceding the training intervention), adult (17-35 years), human participants were selected for the systematic review. A total of 40 studies conformed to these criteria.

RESULTS

Eccentric training elicits greater improvements in muscle strength, although in a largely mode-specific manner. Superior enhancements in power and stretch-shortening cycle (SSC) function have also been reported. Eccentric training is at least as effective as other modalities in increasing muscle cross-sectional area (CSA), while the pattern of hypertrophy appears nuanced and increased CSA may occur longitudinally within muscle (i.e. the addition of sarcomeres in series). There appears to be a preferential increase in the size of type II muscle fibres and the potential to exert a unique effect upon fibre type transitions. Qualitative and quantitative changes in tendon tissue that may be related to the magnitude of strain imposed have also been reported with eccentric training.

CONCLUSIONS

Eccentric training is a potent stimulus for enhancements in muscle mechanical function, and muscle-tendon unit (MTU) morphological and architectural adaptations. The inclusion of eccentric loads not constrained by concentric strength appears to be superior to traditional resistance training in improving variables associated with strength, power and speed performance.

Contralateral effects of unilateral training: sparing of muscle strength and size after immobilization

The contralateral effects of unilateral strength training, known as cross-education of strength, date back well over a century. In the last decade, a limited number of studies have emerged demonstrating the preservation or "sparing" effects of cross-education during immobilization. Recently published evidence reveals that the sparing effects of cross-education show muscle site specificity and involve preservation of muscle cross-sectional area. The new research also demonstrates utility of training with eccentric contractions as a potent stimulus to preserve immobilized limb strength across multiple modes of contraction. The cumulative data in nonclinical settings suggest that cross-education can completely abolish expected declines in strength and muscle size in the range of ∼13% and ∼4%, respectively, after 3-4 weeks of immobilization of a healthy arm. The evidence hints towards the possibility that unique mechanisms may be involved in preservation effects of cross-education, as compared with those that lead to functional improvements under normal conditions. Cross-education effects after strength training appear to be larger in clinical settings, but there is still only 1 randomized clinical trial demonstrating the potential utility of cross-education in addition to standard treatment. More work is necessary in both controlled and clinical settings to understand the potential interaction of neural and muscle adaptations involved in the observed sparing effects, but there is growing evidence to advocate for the clinical utility of cross-education.

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.

The Effect of a Muscle Weight-Bearing and Aerobic Exercise Program on the Body Composition, Muscular Strength, Biochemical Markers, and Bone Mass of Obese Patients Who Have Undergone Gastric Bypass Surgery

BACKGROUND

The effect of an exercise program on the body composition, muscular strength (MS), biochemical markers, and bone mineral density (BMD) of individuals undergoing gastric bypass is unclear. We assessed lean mass (LM), MS, bone remodeling markers, and BMD before and after supervised weight-bearing and aerobic exercise training in obese patients who underwent Roux-en-Y gastric bypass (RYGB).

METHODS

This study included 37 obese patients (81.1% women, mean age 38.2 years, mean body mass index 42.4 ± 0.5 kg/m²). Whole body densitometry was used to evaluate pre- and postoperative BMD, total body fat, and LM. Serum calcium, parathyroid hormone, 25-hydroxyvitamin D, and bone remodeling markers were measured. MS was determined through the concentric 10 repetition maximum test. Postoperatively, participants were divided into two groups: the training group, who followed an exercise program (TG, n = 18), and the control group, who did not (CG, n = 19).

RESULTS

After 1 year, the TG showed a lower decrease in total BMD and at the lumbar spine and right hip compared with the CG (p < 0.001). The TG had lower mass reduction and an increase in upper limb LM compared with the CG (both p < 0.05). There was no significant difference between groups in bone markers or calcium metabolism. MS was higher in the TG than the CG (p < 0.05).

CONCLUSION

The supervised exercise program attenuated lumbar spine and right hip BMD loss and improved LM in the arms and overall MS but did not affect bone remodeling.

Upper Extremity Strength Imbalance after Mastectomy and the Effect of Resistance Training

The purpose of this non-randomized pre/post comparison trial was to explore the effect of resistance training (RT) on upper extremity strength imbalance in breast cancer survivors. Seventeen right-side dominant female breast cancer survivors (age: 58.2±2.7 years; BMI: 27.8±1.1 kg/m ² ) with right-sided (RSM) or left-sided (LSM) mastectomy completed strength testing (30-second arm curl) before and after an 8-week RT program. At baseline, LSM (n=8) had equal strength bilaterally (right=16.8±1.1 repetitions; left=16.4±1.4 repetitions), whereas RSM (n=9) had impaired strength on the right (16.7±1.3 repetitions) compared to the left (18.6±1.1 repetitions) side ( p <0.01). After RT, RSM increased strength by 25% on the right (initially weaker) side and 19% on the left (initially stronger) side, which resolved the imbalance. By comparison LSM increased 19% on both sides that were initially equal in strength. Based on our findings, breast cancer survivors with dominant-side mastectomy are at risk for upper extremity strength imbalance that can be resolved with a relatively short-term RT program.

Skeletal Muscle Remodeling in Response to Eccentric vs. Concentric Loading: Morphological, Molecular, and Metabolic Adaptations

Skeletal muscle contracts either by shortening or lengthening (concentrically or eccentrically, respectively); however, the two contractions substantially differ from one another in terms of mechanisms of force generation, maximum force production and energy cost. It is generally known that eccentric actions generate greater force than isometric and concentric contractions and at a lower metabolic cost. Hence, by virtue of the greater mechanical loading involved in active lengthening, eccentric resistance training (ECC RT) is assumed to produce greater hypertrophy than concentric resistance training (CON RT). Nonetheless, prevalence of either ECC RT or CON RT in inducing gains in muscle mass is still an open issue, with some studies reporting greater hypertrophy with eccentric, some with concentric and some with similar hypertrophy within both training modes. Recent observations suggest that such hypertrophic responses to lengthening vs. shortening contractions are achieved by different adaptations in muscle architecture. Whilst the changes in muscle protein synthesis in response to acute and chronic concentric and eccentric exercise bouts seem very similar, the molecular mechanisms regulating the myogenic adaptations to the two distinct loading stimuli are still incompletely understood. Thus, the present review aims to, (a) critically discuss the literature on the contribution of eccentric vs. concentric loading to muscular hypertrophy and structural remodeling, and, (b) clarify the molecular mechanisms that may regulate such adaptations. We conclude that, when matched for either maximum load or work, similar increase in muscle size is found between ECC and CON RT. However, such hypertrophic changes appear to be achieved through distinct structural adaptations, which may be regulated by different myogenic and molecular responses observed between lengthening and shortening contractions.

The Effects of Eccentric Contraction Duration on Muscle Strength, Power Production, Vertical Jump, and Soreness

Mike, JN, Cole, N, Herrera, C, VanDusseldorp, T, Kravitz, L, and Kerksick, CM. The effects of eccentric contraction duration on muscle strength, power production, vertical jump, and soreness. J Strength Cond Res 31(3): 773-786, 2017-Previous research has investigated the effects of either eccentric-only training or comparing eccentric and concentric exercise on changes related to strength and power expression, but no research to date has investigated the impact of altering the duration of either the concentric or the eccentric component on these parameters. Therefore, the purpose of this study was to assess the duration of eccentric (i.e., 2-second, 4-second vs. 6-second) muscle contractions and their effect on muscle strength, power production, vertical jump, and soreness using a plate-loaded barbell Smith squat exercise. Thirty college-aged men (23 ± 3.5 years, 178 ± 6.8 cm, 82 ± 12 kg, and 11.6 ± 5.1% fat) with 3.0 ± 1.0 years of resistance training experience and training frequency of 4.3 ± 0.9 days per week were randomized and assigned to 1 of 3 eccentric training groups that incorporated different patterns of contraction. For every repetition, all 3 groups used 2-second concentric contractions and paused for 1 second between the concentric and eccentric phases. The control group (2S) used 2-second eccentric contractions, whereas the 4S group performed 4-second eccentric contractions and the 6S group performed 6-second eccentric contractions. All repetitions were completed using the barbell Smith squat exercise. All participants completed a 4-week training protocol that required them to complete 2 workouts per week using their prescribed contraction routine for 4 sets of 6 repetitions at an intensity of 80-85% one repetition maximum (1RM). For all performance data, significant group × time (G × T) interaction effects were found for average power production across all 3 sets of a squat jump protocol (p = 0.04) while vertical jump did not reach significance but there was a trend toward a difference (G × T, p = 0.07). No other significant (p > 0.05) G × T interaction effects were found for the performance variables. All groups showed significant main effects for time in 1RM (p < 0.001), vertical jump (p = 0.004), peak power (p < 0.001), and average power (p < 0.001). Peak velocity data indicated that the 6S group experienced a significant reduction in peak velocity during the squat jump protocol as a result of the 4-week training program (p = 0.03). Soreness data revealed significant increases across time in all groups at both week 0 and week 4. Paired sample t-tests revealed greater differences in soreness values across time in the 2S group. The results provide further evidence that resistance training with eccentrically dominated movement patterns can be an effective method to acutely increase maximal strength and power expression in trained college age men. Furthermore, longer eccentric contractions may negatively impact explosive movements such as the vertical jump, whereas shorter eccentric contractions may instigate greater amounts of soreness. These are important considerations for the strength and conditioning professional to more fully understand that expressions of strength and power through eccentric training and varying durations of eccentric activity can have a significant impact for populations ranging from athletes desiring peak performance.

Superior Effects of Eccentric to Concentric Knee Extensor Resistance Training on Physical Fitness, Insulin Sensitivity and Lipid Profiles of Elderly Men

It has been reported that eccentric training of knee extensors is effective for improving blood insulin sensitivity and lipid profiles to a greater extent than concentric training in young women. However, it is not known whether this is also the case for elderly individuals. Thus, the present study tested the hypothesis that eccentric training of the knee extensors would improve physical function and health parameters (e.g., blood lipid profiles) of older adults better than concentric training. Healthy elderly men (60–76 years) were assigned to either eccentric training or concentric training group (n = 13/group), and performed 30–60 eccentric or concentric contractions of knee extensors once a week. The intensity was progressively increased over 12 weeks from 10 to 100% of maximal concentric strength for eccentric training and from 50 to 100% for concentric training. Outcome measures were taken before and 4 days after the training period. The results showed that no sings of muscle damage were observed after any sessions. Functional physical fitness (e.g., 30-s chair stand) and maximal concentric contraction strength of the knee extensors increased greater (P ≤ 0.05) after eccentric training than concentric training. Homeostasis model assessment, oral glucose tolerance test and whole blood glycosylated hemoglobin showed improvement of insulin sensitivity only after eccentric training (P ≤ 0.05). Greater (P ≤ 0.05) decreases in fasting triacylglycerols, total, and low-density lipoprotein cholesterols were evident after eccentric training than concentric training, and high-density lipoprotein cholesterols increased only after eccentric training. These results support the hypothesis and suggest that it is better to focus on eccentric contractions in exercise medicine.

Impact of Strength Training on Bone Mineral Density in Patients Infected With HIV Exhibiting Lipodystrophy

This study aimed to evaluate the impact of strength training on bone mineral density (BMD) in individuals harboring HIV exhibiting lipodystrophy. The study included 20 subjects (16 men) aged 50.60 ± 6.40 years with reduced BMD, presenting positive serology for HIV, using highly active antiretroviral therapy, and performing no regular practice of physical exercise before being enrolled in the study. Bone mineral density levels were evaluated by dual-energy x-ray absorptiometry in the lumbar spine, femoral neck, and 1/3 radius, before and after 36 sessions (12 weeks) of strength training. Compared with pre-exercise period, the results showed increased BMD in lumbar spine (3.28%; p = 0.012), femoral neck (8.45%; p = 0.044), and 1/3 radius (5.41%; p = 0.035). This is the first study evaluating the impact of strength training in patients living with HIV and exhibiting lipodystrophy, showing an increased BMD in all the regions measured (lumbar spine, femoral neck, and 1/3 radius). This study showed the beneficial impact of the strength training on BMD increase in patients living with HIV as an effective and available approach to improve bone health.

Muscle damage and inflammation after eccentric exercise: can the repeated bout effect be removed?

The current consensus in exercise physiology is that the repeated bout effect always appears after few eccentric exercise sessions. This is the first attempt to challenge this tenet, by exploiting specificity in muscle plasticity. More specifically, we examined whether the opposing adaptations in muscle induced after concentric and eccentric exercise can attenuate and/or remove the repeated bout effect. Seventeen young men were randomly assigned into one of the following groups: (1) the alternating eccentric‐concentric exercise group; and (2) the eccentric‐only exercise group. Both groups performed 8 weeks of resistance exercise using the knee extensors of both legs on an isokinetic dynamometer. The alternating eccentric‐concentric exercise group performed an alternating exercise protocol, switching between eccentric‐only and concentric‐only exercise every 4 weeks, while the eccentric‐only group performed eccentric exercise. Evaluation of muscle damage using physiological (isometric torque, delayed onset muscle soreness, and range of movement) and biochemical (creatine kinase) markers and inflammation (C‐reactive protein) was performed at weeks 1, 5, and 10. Baseline isometric peak torque was also evaluated at week 14 after another cycle (4 weeks) of alternating or eccentric‐only exercise training. In the alternating eccentric‐concentric exercise group, the concentric exercise training performed prior to eccentric exercise reduced dramatically the repeated bout effect by reversing muscle back to its unaccustomed state. On the contrary, the eccentric‐only exercise group exhibited a typical manifestation of the repeated bout effect. Interestingly, muscle strength was elevated similarly for both alternating and eccentric‐only exercise groups after 13 weeks of training. The alternating eccentric‐concentric exercise scheme, implemented in the present study, has for the first time successfully overcame the repeated bout effect. The similarity in muscle strength measurements following the two protocols is against the notion that inflammation plays an important role in exercise‐induced adaptations in muscle.

Early structural remodeling and deuterium oxide-derived protein metabolic responses to eccentric and concentric loading in human skeletal muscle

We recently reported that the greatest distinguishing feature between eccentric (ECC) and concentric (CON) muscle loading lays in architectural adaptations: ECC favors increases in fascicle length (Lf), associated with distal vastus lateralis muscle (VL) hypertrophy, and CON increases in pennation angle (PA). Here, we explored the interactions between structural and morphological remodeling, assessed by ultrasound and dual x-ray absorptiometry (DXA), and long-term muscle protein synthesis (MPS), evaluated by deuterium oxide (D₂O) tracing technique. Ten young males (23 ± 4 years) performed unilateral resistance exercise training (RET) three times/week for 4 weeks; thus, one-leg trained concentrically while the contralateral performed ECC exercise only at 80% of either CON or ECC one repetition maximum (1RM). Subjects consumed an initial bolus of D₂O (150 mL), while a 25-mL dose was thereafter provided every 8 days. Muscle biopsies from VL midbelly (MID) and distal myotendinous junction (MTJ) were collected at 0 and 4-weeks. MPS was then quantified via GC–pyrolysis–IRMS over the 4-week training period. Expectedly, ECC and CON RET resulted in similar increases in VL muscle thickness (MT) (7.5% vs. 8.4%, respectively) and thigh lean mass (DXA) (2.3% vs. 3%, respectively), albeit through distinct remodeling: Lf increasing more after ECC (5%) versus CON (2%) and PA increasing after CON (7% vs. 3%). MPS did not differ between contractile modes or biopsy sites (MID-ECC: 1.42 vs. MID-CON: 1.4% day⁻¹; MTJ-ECC: 1.38 vs. MTJ-CON: 1.39% day⁻¹). Muscle thickness at MID site increased similarly following ECC and CON RET, reflecting a tendency for a contractile mode-independent correlation between MPS and MT (P = 0.07; R² = 0.18). We conclude that, unlike MT, distinct structural remodeling responses to ECC or CON are not reflected in MPS; the molecular mechanisms of distinct protein deposition, and/or the role of protein breakdown in mediating these responses remain to be defined.

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.

Effects of whole body vibration and resistance training on bone mineral density and anthropometry in obese postmenopausal women

Objective. The aim of this study was to evaluate the impact of two exercise programs, whole body vibration and resistance training on bone mineral density (BMD) and anthropometry in obese postmenopausal women. Material and Methods. Eighty Egyptian obese postmenopausal women were enrolled in this study; their age ranged from 50 to 68 years. Their body mass index ranged (30-36 kg/m(2)). The exercise prescription consisted of whole body vibration (WBV) and resistance training. Bone mineral density (BMD) and anthropometrical parameters were measured at the beginning and at the end of the study. Changes from baseline to eight months in BMD and anthropometric parameters were investigated. Results. BMD at the greater trochanter, at ward's triangle, and at lumbar spine were significantly higher after physical training, using both WBV and resistive training. Moreover, both exercise programs were effective in BMI and waist to the hip ratio. Simple and multiple regression analyses showed significant associations between physical activity duration and BMD at all sites. The highest values of R (2) were found for the models incorporating WBV plus BMI. Conclusion. The study suggests that both types of exercise modalities had a similar positive effect on BMD at all sites in obese postmenopausal women. Significant association was noted between physical activity and anthropometric variables and BMD measures at all sites.

Optimizing the benefits of exercise on physical function in older adults

As the number of older adults continues to rise worldwide, the prevention of physical disability among seniors is an increasingly important public health priority. Physical exercise is among the best known methods of preventing disability, but accumulating evidence indicates that considerable variability exists in the responsiveness of older adults to standard training regimens. Accordingly, a need exists to develop tailored interventions to optimize the beneficial effects of exercise on the physical function of older adults at risk for becoming disabled. The present review summarizes the available literature related to the use of adjuvant or alternative strategies intended to enhance the efficacy of exercise in improving the physical function of older adults. Within this work, we also discuss potential future research directions in this area.

Relationship of body fat and its distribution with bone mineral density in Indian population

Obesity has been associated with increased bone mineral density (BMD). There is evidence of differential effect of regional fat on BMD. Hence, we undertook this study to evaluate the correlation between total body fat and its distribution with BMD in nonobese (mean body mass index: 25.0 ± 4.7 kg/m²) Indian adult volunteers. A total of 2347 participants (men: 39.4% and women: 60.6%) included in this cross-sectional study were divided according to sex and age. Fasting blood samples were drawn for biochemical parameters. Percent total body, truncal, and leg fat and BMD at lumbar spine, femur, and forearm were measured by dual-energy X-ray absorptiometry. The BMD at all sites (radius, femur, and spine) increased from lowest to highest quartiles of percent body fat. Percent truncal fat was positively correlated with BMD at all sites in both sexes, except for femoral neck in men, where it had negative correlation. Percent leg fat was positively related with BMD at all sites in premenopausal women, and spine and radius BMD in postmenopausal women. However, in men, it had negative correlation with femoral neck BMD. On multiple regression analysis, regional fat had positive association with BMD at all sites after adjusting for age, sex, lean mass index, 25-hydroxyvitamin D, and intact parathyroid hormone levels. Leg-to-total body fat ratio was negatively associated with BMD at all sites in men and pre- and postmenopausal women. Percent total body and regional fat have positive association with BMD at all sites in men and women.

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.

Prospective analysis of a first MTP total joint replacement. Evaluation by bone mineral densitometry, pedobarography, and visual analogue score for pain

BACKGROUND

We hypothesized that a total replacement of the first metatarsophalangeal joint (MTP-1) would alter the walking pattern with medialisation of the ground reaction force (GRF) of the foot and subsequently cause an increase in bone mineral density (BMD) in the medial metatarsal bones and a decline of BMD in the lateral metatarsal bones.

METHODS

Twelve patients receiving total joint replacements (Roto-Glide(®)) of MTP-1 were enrolled in a prospective cohort. BMD and pedobarography of the heel bone and the metatarsal heads were performed preoperatively and at least 12 months postoperatively.

RESULTS

BMD in the lateral metatarsals and GRF under the lateral column of the operated feet decreased significantly on the operated feet.

CONCLUSIONS

Total joint replacement of MTP-1 tends to reduce GRF under the lateral column of the foot causing a corresponding decline in BMD and pedobarographic measures. Our findings support the further use of the Roto-Glide(®) prosthesis for osteoarthritis of the first metatarsophalangeal joint.

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.

Bone density, balance and quality of life of postmenopausal women taking alendronate participating in different physical activity programs

BACKGROUND

The objective of this study was to determine the effects of different physical activity (PA) programs on bone density, balance and quality of Life of postmenopausaL women taking concomitant aLendronate. A quasi-experimental study was conducted with 35 volunteers divided into four groups: practitioners of resistance training (RTG, n = 9, 49.8±4.2 years), judo (JUG, n= 11, 52.2 ±5.3 years), water aerobics (WAG, n = 8, 57.1 ±7.4 years) and the control group (CG, n = 7, 53.8±4.4 years).

METHODS

The following assessment tools were used: bone mineral density (BMD) measured by dual X-ray absorptiometry of the spine and proximal femur, the 'Osteoporosis Assessment Questionnaire' (OPAQ) and the 'Static Balance Test with Visual Control'. The physical activities were planned for 12 months in cycles with different intensities. A two-way analysis of variance (ANOVA) was used for analysis between groups, and a Scheffe post-hoc test was used for multiple comparisons.

RESULTS

The multiple comparisons results showed that the RTG and JUG groups were significantly more efficient in the variables studied, including: Lumbar BMD (Δ% = 6.8%, p = 0.001), balance (Δ% = 21.4%, p = 0.01), OPAQ (Δ% = 9.1%, p = 0.005) and Lumbar BMD (Δ% = 6.4%, p = 0.003), balance (Δ% = U%, p = 0.02) and OPAQ (Δ% = 16.8%, p =0.000) compared with the CG. Furthermore, the RTG (Δ% = 4.8%, p =0.02) was significantly better than the WAG for the neck of femur BMD, and the JUG (Δ% = 16.8, p = 0.0003) also demonstrated superiority to the WAG in the OPAQ.

CONCLUSIONS

The physical activities studied appear to improve BMD, balance and quality of Life of postmenopausaL women taking a bisphosphonate. In this small sample, the RTG and the JUG groups were superior to the other groups.

Moderate resistive training maintains bone mineral density and improves functional fitness in postmenopausal women

Twenty five subjects were randomized to untrained (UN) and resistive-trained (RT) groups. The RT group exercised three sessions per week at 60%–70% of the load according to individual 1RM test during 24 weeks. Both groups were evaluated before and after protocol period assessing lumbar spine (LS) and femoral neck (FN) BMD by dual-energy X-ray absorptiometry, VO₂ max, and neuromuscular fitness. After 24 weeks, there were significant reductions in LS (0.89 ± 0.16% loss) and FN BMD (1.54 ± 0.35% loss) for UN but no change was found in the TR (LS: 0.01 ± 0.12% and FN: 0.04 ± 0.05% loss). The UN group had no changes in neuromuscular performance. However, RT exhibited a significant improvement on the functional fitness parameters evaluated, with the exception of agility. Our results indicate RT suppresses the decline in BMD and simultaneously improves the functional fitness of postmenopausal women without hormone replacement therapy, which may reduce fall risk and related bone fractures.

Efeitos do treinamento resistido sobre variáveis relacionadas com a baixa densidade óssea de mulheres menopausadas tratadas com alendronato

A osteoporose é uma doença crônica que atinge o esqueleto humano. OBJETIVO: Verificar os efeitos do treinamento resistido sobre a densidade mineral óssea (DMO), força muscular, equilíbrio e qualidade de vida em mulheres menopausadas em tratamento com alendronato. MÉTODOS: Participaram do estudo 16 voluntárias. Elas foram separadas em dois grupos: que praticaram o treino resistido (n = 9, 49,7 ± 4,2 idade) e que constituíram o grupo controle (n = 7, 53,8 ± 4,4 idade). Os instrumentos de avaliação seguintes foram usados: a absorciometria de dupla energia por raios X -DXA (que mediu a coluna lombar L2-L4, colo do fêmur, triângulo de Wards e trocanter maior), o Osteoporosis Assessment Questionnaire (OPAQ) e um teste de equilíbrio. O treinamento foi periodizado em 12 meses, divididos em seis ciclos com intensidade de 70-90% da carga máxima (10RM). Testes paramétricos (t ou Wilcoxon), para análise intragrupo e (Anova) para intergrupos, foram usados. RESULTADOS: Foram encontradas diferenças significativas favoráveis ao grupo que treinou nos sítios da lombar L2-L4 (6,8%, p = 0,001), colo do fêmur (4,8%, p = 0,005) e trocanter (0,76%, p = 0,005). Além de diferenças significativas também para o equilíbrio corporal (21,4%, p = 0,001), qualidade de vida (9,1%, p = 0,001) e todas as medidas de força como na pressão de pernas 45° (49,3%, p < 0,001). CONCLUSÃO: Os resultados sugerem que a metodologia aplicada ao treino resistido pode ser recomendada a mulheres menopausadas com baixa DMO.

Physical approach for prevention and treatment of osteoporosis

Osteoporosis and its consequent fractures are a major problem in public health. To complement the conventional pharmacological treatment for this metabolic disease, non-pharmacological treatment options have been developed in the last decades. Several studies demonstrate that physical exercise programs including impact exercises, specific strength training, balance and coordination training may maintain or increase spine and hip bone mineral density as well as decrease the frequency of falls among osteoporotic and osteopenic patients. Furthermore, some physical agents such as vibratory platforms, low intensity electrical stimulation, laser therapy and ultrasound show positive effects on osteoporotic tissue as well. Consequently, while planning treatment for an osteoporotic patient, non-pharmacological management options should be considered and integrated to the conventional treatment in order to maximize its effects and improve the quality of life of these patients.

Simulated resistance training during hindlimb unloading abolishes disuse bone loss and maintains muscle strength

This study was designed to determine the effectiveness of simulated resistance training (SRT) without weight bearing in attenuating bone and muscle loss during 28 day hindlimb unloading (HU) in mature male rats. An ambulatory control group (CC) and four groups of HU rats were used: HU, HU + anesthesia (ANHU), HU + eccentric muscle contractions (HU + ECC), and HU + isometric and eccentric muscle contractions (HU + ISO/ECC). Animals in the two SRT groups were trained once every other day at 100% daily peak isometric torque (P(0)). HU resulted in significantly lower plantarflexor muscle mass (-33% versus CC) and reduced isometric strength (-10%), which reductions were partially attenuated in both training groups. Significantly reduced total and cancellous volumetric bone mineral density (vBMD) and total bone mineral content (BMC) at the proximal tibia metaphysis (PTM) also was evidenced in HU and ANHU groups compared with both SRT groups (p < .05). Training resulted in greater increases in cortical bone mass and area compared with all other groups (p < .05). Fourfold higher material properties of PTM cancellous bone were demonstrated in SRT animals versus HU or CC animals. A significant reduction in midshaft periosteal bone formation rate (BFR) in the HU group (-99% versus CC) was completely abolished in HU + ECC (+656% versus CC). These results demonstrate that high-intensity muscle contractions, independent of weight-bearing forces, can effectively mitigate losses in muscle strength and provide a potent stimulus to bone during prolonged disuse.