Nonspecific Resistance Training and Swimming Performance: Strength or Power? A Systematic Review.

ABSTRACT: Muniz-Pardos, B, Gomez-Bruton, A, Matute-Llorente, A, Gonzalez-Aguero, A, Gomez-Cabello, A, Gonzalo-Skok, O, Casajus, JA, and Vicente-Rodriguez, G. Nonspecific resistance training and swimming performance: Strength or power? A systematic review. J Strength Cond Res 36(4): 1162-1170, 2022-The purpose of this systematic review was to determine the type of nonspecific resistance intervention that is more effective to enhance swimming performance and to determine the nonspecific strength- or power-related variable that better predicts swimming performance. A search was conducted on PubMed, Cochrane Plus, and SportDiscus up to June 2018. Studies were distributed into 4 categories: dry-land strength (DLS), dry-land power (DLP), combination of training methods, and strength and power in start performance. From 1,844 citations, 33 met the inclusion criteria. Cross-sectional DLS studies showed positive associations between swimming performance and DLS development (especially through upper-body isometric assessments), although the efficacy of DLS training interventions remains unclear. Dry-land power training (principally through plyometrics) was a proficient, nonspecific method to enhance swimming block start performance (SBS; the start phase off the block and during the first 5-15 m), and jump assessment was the best predictor of SBS. Some pioneering nonspecific practices such as the acute exposure to high altitude or the maintenance of a high core temperature during the transition phase before competition seem to improve performance, although more research is required to confirm their efficacy. Further high-quality intervention studies are required to clarify the effect of DLP training on sprint swimming performance.

Potential health-related behaviors for pre-school and school-aged children during COVID-19 lockdown: A narrative review.

As a consequence of the COVID-19 pandemic, different measures have been implemented by governments from each affected country. Such measures usually involve restrictions on the movement of citizens, and have had a profound effect on usual activities and timetables. As a result of school closures and strict restrictions regarding going outside home, children have been one of the most disadvantaged population groups during the lockdown period. We therefore aimed to investigate potential health risk behaviors amongst isolated pre-school and school-aged children. We retrieved relevant articles from MEDLINE, Web of Science, PsycInfo, and Scopus databases to describe identified health-related behaviors (i.e. screen exposure, environmental influence, physical activity and fitness, sedentariness, sleep patterns, eating habits, psychological response, body composition, and injuries) in relation to social isolation and social deprivation of children without previous illness or conditions. This review depicts the potential health-related behaviors according to related literature, and put the focus on future short and long-term sequels of social isolation. Socio-affective complications and insufficient physical activity are underscored as two of the main concerns, particularly among socio-economic deprived children. Both issues could be effectively addressed with either adequate parental or community guidance.

Estimation of the second ventilatory threshold through ventricular repolarization profile analysis.

Under the hypothesis that sympathetic control of ventricular repolarization may change once the second ventilatory threshold (VT2) has been reached, a novel methodology for non-invasive VT2 estimation based on the analysis of the T wave from the electrocardiogram (ECG) is proposed, and potential underlying physiological mechanisms are suggested. 25 volunteers (33.4 ± 5.2 years) underwent an incremental power cycle ergometer test (25 W/minute). During the test, respiratory gas exchange and multi-lead ECG were acquired. The former was employed to determine VT2, used here as a reference, whereas the latter was used to compute the temporal profiles of an index of ventricular repolarization instability (dT) and its low-frequency (LF) oscillations (LFdT). The sudden increases observed in dT and LFdT profiles above an established heart rate threshold were employed to derive VT2 estimates, referred to as VT2d T and VT2LF d T , respectively. Estimation errors of -4.7 ± 25.2 W were obtained when considering VT2d T . Errors were lower than the one-minute power increment of 25 W in 68% of the subjects and lower than 50 W in 89.5% of them. When using VT2LF d T , estimation error was of 15.3 ± 32.4 W. Most of the subjects shared common characteristic dT and LFdT profiles, which could be reflecting changes in the autonomic control of ventricular repolarization before and after reaching VT2. The analysis of ventricular repolarization dynamics during exercise allows non-invasive ECG-based estimation of VT2, possibly in relation to changes in the autonomic control of ventricular electrical activity when VT2 is reached.

High leisure-time physical activity reduces the risk of long-term sickness absence.

OBJECTIVES: This study examined the association of leisure-time physical activity (LTPA) with the risk of long-term sickness absence (LTSA). METHODS: A total of 10 427 subjects from the general working population in Denmark answered questions about physical activity habits, health and work environment in the 2010 Danish Work Environment Cohort Study (DWECS). Data on LTSA (≥6 consecutive weeks during 2-year follow-up) were obtained from the Danish Register for Evaluation of Marginalization (DREAM). Cox regression analysis censored for competing events and adjusted for potential confounders (age, sex, BMI, smoking habits, depression, cancer, back diseases, previous LTSA, occupational social class, and psychosocial work environment) estimated the association between the predictor (LTPA) and the outcome variable (LTSA). During the 2-year follow-up period, 9.2% of the studied population experienced LTSA. RESULTS: In the general working population, moderate LTPA was not associated with LTSA (HR = 0.89, 95% CI: 0.72-1.09), while high LTPA showed a tendency (HR = 0.77, 95% CI: 0.59-1.01). In subgroup analyses, women below the age of 45 years with high LTPA showed a significantly lower risk of LTSA when compared with their low LTPA counterparts (HR = 0.44, 95% CI: 0.25-0.78). CONCLUSION: The results suggest that high levels of physical activity during leisure are associated with a lowered risk of LTSA, especially among younger women.

Association Between Physical Activity and Odds of Chronic Conditions Among Workers in Spain.

INTRODUCTION: Prevention of chronic conditions is a major public health challenge, and achieving minimum recommended levels of physical activity aids in reaching this objective. The aim of our study was to investigate whether levels of physical activity were associated with the prevalence of common chronic conditions among the Spanish workforce. METHODS: We retrieved data from the Spanish National Health Survey 2017 (N = 9,695) in which the mean age of participants was 44.4 (standard deviation, 10.4 y), and 47.4% were women. Workers self-reported a set of 6 chronic conditions (ie, chronic low-back pain, chronic neck pain, diabetes, hypertension, depression, and anxiety), and we used the International Physical Activity Questionnaire short form to estimate physical activity. We performed multivariable logistic regression adjusted for possible confounders to assess associations between physical activity and chronic conditions. RESULTS: The final adjusted model showed that performing less than 600 metabolic equivalent-minutes per week of physical activity was associated with significantly increased odds for chronic conditions (adjusted odds ratio [aOR] = 1.18; 95% CI, 1.07-1.30). Of the sex and age subgroups analyzed, this association was significant in men aged 17 to 44 (aOR = 1.21; 95% CI, 1.00-1.46). Among chronic conditions, low-back pain and anxiety were associated with low levels of physical activity, whereas covariates such as body mass index, smoking habits, education level, and occupational class had an important influence on the association between physical activity and chronic conditions. CONCLUSION: Results suggest that achieving sufficient physical activity could reduce chronic conditions among Spanish workers.

Accurate Prediction Equation to Assess Body Fat in Male and Female Adolescent Football Players.

The aims of this study were (a) to determine which of the most used anthropometric equations was the most accurate to estimate percentage of body fat (%BF), (b) to develop a new specific anthropometric equation, and (c) to validate this football-specific equation. A total of 126 (13.3 ± 0.6 years) football players (86 males and 40 females) participated in the present study. Participants were divided into two groups: 98 players were included in the assessment of existing equations and in the development of the new prediction equation, and 28 players were used to validate it. %BF was measured with dual-energy X-ray absorptiometry (DXA) and also estimated with six different %BF anthropometric equations: Johnston, Slaughter, Carter, Faulkner, Deurenberg, and Santi-Maria. Paired t tests were used to analyze differences between methods. A football-specific equation was developed by a stepwise linear regression. The existing anthropometric equations showed significant bias for %BF when compared with DXA (p < .001; constant error ranged from -4.57% to 9.24%; standard error of estimate ranged from 2.46 to 4.20). On the other hand, the developed football-specific equation was %BF = 11.115 + 0.775 (triceps skinfold) + 0.193 (iliac crest skinfold) - 1.606 (sex). The developed equation demonstrated neither %BF differences (p = .121; constant error = 0.57%; standard error of estimate = 0.36) when compared with DXA, presenting a high cross-validation prediction power (R2 = .85). Published anthropometric equations were not accurate to estimate %BF in adolescent football players. Due to the fact that the developed football-specific equation showed neither differences nor heteroscedasticity when compared with DXA, this equation is recommended to assess %BF in adolescent football players.

Swim-Specific Resistance Training: A Systematic Review.

Muniz-Pardos, B, Gomez-Bruton, A, Matute-Llorente, A, Gonzalez-Aguero, A, Gomez-Cabello, A, Gonzalo-Skok, O, Casajus, JA, and Vicente-Rodriguez, G. Swim-specific resistance training: A systematic review. J Strength Cond Res 33(10): 2875-2881, 2019-The purpose of this systematic review was to determine which type of swim-specific training is most beneficial to enhance swimming performance and to determine which specific strength- or power-related tests better predict swimming performance. A search was conducted on PubMed, Cochrane Plus, and SPORTDiscus up to June 2018. Studies were distributed into 2 main categories: swim-specific dry land resistance training (SDLRT) and specific in-water swimming power training (SSWPT). From 1,844 citations, 25 met the inclusion criteria. It was determined that SSWPT was the most appropriate method to improve swimming performance, with tethered swimming protocols being the most studied and effective. In addition, SDLRT was a competent method to enhance swimming performance, and specifically, the inclusion of inertial training might evoke greater improvements in both strength/power capacities and swimming performance, than traditional resistance training. In conclusion, tether forces showed the greatest associations with swimming performance, although the efficacy of tethered swimming as an SSWPT method is yet to be confirmed. Further research should focus on the effects of SDLRT to verify the greater transfer of dry land resistance practices to swimming performance, with inertial training being potentially more beneficial than traditional resistance training.

Soccer helps build strong bones during growth: a systematic review and meta-analysis.

The aim of this study was to analyze the effects of soccer practice on bone in male and female children and adolescents. MEDLINE, PubMed, SPORTDiscus and Web of Science databases were searched for scientific articles published up to and including October 2016. Twenty-seven studies were included in this systematic review (13 in the meta-analysis). The meta-analysis was performed by using OpenMeta[Analyst] software. It is well documented that soccer practice during childhood provides positive effects on bone mineral content (BMC) and density (BMD) compared to sedentary behaviors and other sports, such as tennis, weightlifting, or swimming. Furthermore, soccer players present higher BMC and BMD in most weight-bearing sites such as the whole body, lumbar spine, hip, and legs. Moreover, bone differences were minimized between groups during prepuberty. Therefore, the maturity status should be considered when evaluating bone. According to meta-analysis results, soccer practice was positively associated with whole-body BMD either in males (mean difference 0.061; 95%CI, 0.042-0.079) or in females (mean difference 0.063; 95%CI, 0.026-0.099). CONCLUSION: Soccer may be considered a sport that positively affects bone mass during growth. Pubertal soccer players presented increased bone mass compared to controls or other athletes; however, these bone differences are minimized during the prepubertal stage. What is known: • It has been described that childhood and adolescence are important periods for bone mass and structure. • Previous studies have demonstrated that soccer participation improves bone mass in male and female children and adolescents. What is new: • The differences between soccer players and controls are more marked during puberty than prepuberty. • Weight-bearing sites such as lumbar spine, hip, femoral neck, trochanter, intertrochanteric region and both legs are particularly sensitive to soccer actions.

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

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

Validation of Heart Rate Monitor Polar RS800 for Heart Rate Variability Analysis During Exercise.

Hernando, D, Garatachea, N, Almeida, R, Casajús, JA, and Bailón, R. Validation of heart rate monitor Polar RS800 for heart rate variability analysis during exercise. J Strength Cond Res 32(3): 716-725, 2018-Heart rate variability (HRV) analysis during exercise is an interesting noninvasive tool to measure the cardiovascular response to the stress of exercise. Wearable heart rate monitors are a comfortable option to measure interbeat (RR) intervals while doing physical activities. It is necessary to evaluate the agreement between HRV parameters derived from the RR series recorded by wearable devices and those derived from an electrocardiogram (ECG) during dynamic exercise of low to high intensity. Twenty-three male volunteers performed an exercise stress test on a cycle ergometer. Subjects wore a Polar RS800 device, whereas ECG was also recorded simultaneously to extract the reference RR intervals. A time-frequency spectral analysis was performed to extract the instantaneous mean heart rate (HRM), and the power of low-frequency (PLF) and high-frequency (PHF) components, the latter centered on the respiratory frequency. Analysis was done in intervals of different exercise intensity based on oxygen consumption. Linear correlation, reliability, and agreement were computed in each interval. The agreement between the RR series obtained from the Polar device and from the ECG is high throughout the whole test although the shorter the RR is, the more differences there are. Both methods are interchangeable when analyzing HRV at rest. At high exercise intensity, HRM and PLF still presented a high correlation (ρ > 0.8) and excellent reliability and agreement indices (above 0.9). However, the PHF measurements from the Polar showed reliability and agreement coefficients around 0.5 or lower when the level of the exercise increases (for levels of O2 above 60%).

Bone Structure and Geometric Properties at the Radius and Tibia in Adolescent Endurance-Trained Cyclists.

OBJECTIVE: To describe cortical and trabecular volumetric bone mineral density (vBMD), bone mineral content (BMC), cross-sectional area (CSA), and bone strength indexes (BSIs) in adolescent endurance-trained cyclists (CYC) and compare them with controls (CON). DESIGN: Descriptive cohort study. PARTICIPANTS: Twenty-five male adolescent CYC and 17 CON. ASSESSMENT OF RISK FACTORS: Peripheral quantitative computed tomography was used to evaluate proximal and distal sites of the radius and tibia. MAIN OUTCOME MEASURES: Total, trabecular, and cortical BMC, vBMD, and CSA were measured. Also, cortical thickness, endosteal and periosteal circumferences, and different BSIs were calculated. Unadjusted analysis of variance and body weight-adjusted analysis of covariance tests were applied between cyclist and control groups. RESULTS: Cyclists were almost 12% lighter than CON (P < 0.05). Unadjusted data showed lower distal total vBMD and proximal cortical BMC and vBMD in cyclists compared with CON at the radius (P < 0.05) and lower distal total and trabecular BMC, vBMD and bone area, proximal total and cortical BMC and vBMD, and cortical bone area at the tibia (P < 0.05). Body weight-adjusted data showed the same differences for distal total vBMD at the radius and total and trabecular BMC and vBMD at the tibia, diaphyseal radius cortical vBMD and tibia total vBMD, cortical BMC and area, and also for tibia cortical thickness and BSI. The rest of differences were no longer detectable and bone area at the distal radius become significantly higher in cyclist compared with CON (P < 0.05). CONCLUSIONS: Adolescent CYC in this study showed lower values of BMC and vBMD at determined sites of the radius and tibia than CON, some of these differences were explained in part by their lower body weight. However, even further adjustment, some differences remained, which indicates that further longitudinal studies are needed to better understand if cycling influences these differences.

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

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

Blood and Urinary Abnormalities Induced During and After 24-Hour Continuous Running: A Case Report.

In this reported clinical case, a healthy and well-trained male subject [aged 37 years, maximal oxygen uptake (V[Combining Dot Above]O2max) 64 mL·kg·min] ran for 23 hours and 35 minutes covering 160 km (6.7 km/h average running speed). The analysis of hematological and biochemical parameters 3 days before the event, just after termination of exercise, and after 24 and 48 hours of recovery revealed important changes on muscle and liver function, and hemolysis. The analysis of urine sediments showed an increment of red and white blood cells filtrations, compatible with transient nephritis. After 48 hours, most of these alterations were recovered. Physicians and health professionals who monitor such athletic events should be aware that these athletes could exhibit transient symptoms compatible with severe pathologies and diseases, although the genesis of these blood and urinary abnormalities are attributable to transient physiological adaptations rather to pathological status.

High muscular fitness level may positively affect bone strength and body composition in children with overweight and obesity.

Muscular fitness plays a major role in bone health and body composition in overweight and obese children. It is key that the development of this muscle fitness is affected by absolute isometric strength and dynamic strength. PURPOSE: To compare bone health and body composition between overweight/obese children considering muscular fitness (MF) levels, and to investigate whether weight-bearing dynamic or absolute isometric strength, both involved in the development of this muscular fitness, are more related with bone health. METHODS: MF of 59 overweight or obese children (10.1 ± 0.9 years, 27 females) was measured by a countermovement jump (CMJ), handgrip, and maximal isometric strength of knee extension. Participants were divided into four groups depending on their MF level performing a cluster analysis: 16 children with high MF (HMF) in all tests, 18 with high performance in isometric strength (HIS), 15 with high performance in CMJ (HCMJ) and 10 low isometric and low dynamic force values (LMF). Body composition values were measured by dual energy X-ray absorptiometry, and bone strength values were assessed by peripheral quantitative computed tomography. Motor skills were evaluated using TGMD-3. Multivariate analysis of covariance test was applied to analyse bone strength differences between children in the different MF groups, using maturity offset, height and weight as covariates, and correlations were investigated. RESULTS: HMF excelled in bone health. HIS had higher cortical bone area, periosteal circumference, bone mass, polar strength strain index and fracture load than LMF, while HCMJ only showed better results in trabecular bone area than LMF. HMF had significantly better values of fracture load and periosteal and endosteal circumferences than HCMJ, but not than HIS. CONCLUSIONS: High MF level shows positive effects on bone health in overweight/obese children. Those with highest isometric strength had better bone health compared to those with higher dynamic strength. TRIAL REGISTRATION: The research project was registered in a public database Clinicaltrials.gov in June 2020 with the identification number NCT04418713.

Effects of whole-body vibration on body composition, microbiota, cardiometabolic markers, physical fitness, and quality of life after bariatric surgery: protocol for a randomized controlled trial.

BACKGROUND: Morbid obesity is a complex chronic condition characterized by a body mass index of 40 kg/m2 or higher. The incidence of the condition is on the rise in developed countries, and bariatric surgery has been proposed as a potential solution to address this trend. Nonetheless, bariatric surgery may also result in adverse effects, including a reduction in bone mineral density (BMD) and muscle mass, as well as an increased risk of fractures. The present study aims to elucidate the effects of bariatric surgery and whole-body vibration (WBV) training on body composition, microbiota, physical fitness, quality of life, and cardiometabolic markers. METHODS: Twenty-eight participants (14 females), aged 18 to 50 years, will undergo sleeve gastrectomy surgery. They will be randomly allocated into a control group or a WBV training group. The WBV group will train three times per week with increasing intensities and duration ranging from 30 to 45 min over the 4-month training period. Measurements of body composition (dual-energy X-ray absorptiometry and peripheral quantitative computed tomography), physical fitness (muscular strength, agility, cardiorespiratory fitness, and balance), gait biomechanics, cardiometabolic markers, gut microbiota, quality of life, and physical activity levels will be collected at four different time points: (1) prior to the surgery, (2) 45 days post-surgery, (3) 6 months post-surgery, and (4) 18 months post-surgery. DISCUSSION: Both groups are expected to experience improvements in most of the aforementioned variables. Nonetheless, we expect the WBV group to show larger improvements proving that the training is effective and safe. TRIAL REGISTRATION: Clinicaltrials.gov NCT05695599. Registered on January 25, 2023.

Design of a Computer Model for the Identification of Adolescent Swimmers at Risk of Low BMD.

This paper aims to elaborate a decision tree for the early detection of adolescent swimmers at risk of presenting low bone mineral density (BMD), based on easily measurable fitness and performance variables. The BMD of 78 adolescent swimmers was determined using dual-energy X-ray absorptiometry (DXA) scans at the hip and subtotal body. The participants also underwent physical fitness (muscular strength, speed, and cardiovascular endurance) and swimming performance assessments. A gradient-boosting machine regression tree was built to predict the BMD of the swimmers and to further develop a simpler individual decision tree. The predicted BMD was strongly correlated with the actual BMD values obtained from the DXA (r = 0.960, p < 0.001; root mean squared error = 0.034 g/cm2). According to a simple decision tree (74% classification accuracy), swimmers with a body mass index (BMI) lower than 17 kg/m2 or a handgrip strength inferior to 43 kg with the sum of both arms could be at a higher risk of having a low BMD. Easily measurable fitness variables (BMI and handgrip strength) could be used for the early detection of adolescent swimmers who are at risk of suffering from low BMD.

Effects of multicomponent training and detraining on the fitness of older adults with or at risk of frailty: results of a 10-month quasi-experimental study.

The aims of this study were (1) to analyse the effects of a 6-month multicomponent training (MCT) on the physical fitness of older adults with or at risk of frailty; (2) to study the consequences of a 4-month detraining period; (3) to analyse the influence of frailty status on the training and detraining adaptations. A total of 102 robust, frail and prefrail older adults (80.1 ± 6.1 y) were divided into an intervention (TRAIN) and control group (CON). The TRAIN performed a 6-month MCT, while the CON continued with their usual lifestyle. Fitness assessment was mainly based on the Senior Fitness Test. Four evaluations were carried out; at baseline, and at 3, 6 and 10 months from baseline. Linear mixed models were performed to analyse group by time interactions and to compare differences in changes within groups between different time points. After 6-month MCT, TRAIN showed greater improvements for all fitness variables (group effects p < 0.05, except for flexibility) when compared to the CON. During the 4-month detraining period, TRAIN significantly decreased their balance, upper-limb flexibility and upper and lower-limb strength (all p < 0.05). CON only decreased upper-limb flexibility. When accounting for frailty status in the TRAIN, the frail-prefrail showed lower adaptations to the training and were more affected by detraining than the robust. The presented MCT is a good strategy to improve fitness in this population, but its positive effects are limited in time. It is, therefore, critical to avoid detraining periods.Trial registration: ClinicalTrials.gov identifier: NCT03831841.HighlightsOur 6-month MCT-program improves the physical fitness of robust, frail and prefrail older adultsA detraining period of four months partially deteriorates the physical fitness of robust, frail and prefrail older adults, so it is recommended to promote ongoing exercise programs or smaller break periodsIt seems that those older adults with a more advanced frailty status may not benefit from exercise to the same degree and will be more affected by detraining. Therefore, trainers may need to individualize training protocols to obtain the greatest exercise benefits.

Cycling and bone health: a systematic review.

BACKGROUND: Cycling is considered to be a highly beneficial sport for significantly enhancing cardiovascular fitness in individuals, yet studies show little or no corresponding improvements in bone mass. METHODS: A scientific literature search on studies discussing bone mass and bone metabolism in cyclists was performed to collect all relevant published material up to April 2012. Descriptive, cross-sectional, longitudinal and interventional studies were all reviewed. Inclusion criteria were met by 31 studies. RESULTS: Heterogeneous studies in terms of gender, age, data source, group of comparison, cycling level or modality practiced among others factors showed minor but important differences in results. Despite some controversial results, it has been observed that adult road cyclists participating in regular training have low bone mineral density in key regions (for example, lumbar spine). Conversely, other types of cycling (such as mountain biking), or combination with other sports could reduce this unsafe effect. These results cannot yet be explained by differences in dietary patterns or endocrine factors. CONCLUSIONS: From our comprehensive survey of the current available literature it can be concluded that road cycling does not appear to confer any significant osteogenic benefit. The cause of this may be related to spending long hours in a weight-supported position on the bike in combination with the necessary enforced recovery time that involves a large amount of time sitting or lying supine, especially at the competitive level.

A 21-week bone deposition promoting exercise programme increases bone mass in young people with Down syndrome.

AIM: To determine whether the bone mass of young people with Down syndrome may increase, following a 21-week conditioning training programme including plyometric jumps. METHOD: Twenty-eight participants with Down syndrome (13 females, 15 males) aged 10 to 19 years were divided into exercise (DS-E; n=14; eight females, six males mean age 13y 8mo, SD 2y 6mo) and non-exercise (DS-NE; n=14; five females, nine males mean age 15y 5mo, SD 2y 6mo) groups. Total and regional (hip and lumbar spine [L1-L4]) bone mineral content (BMC) and total lean mass were assessed by dual energy X-ray absorptiometry at baseline and after a 25-minute training session performed twice a week. Repeated-measures analyses of variation were applied to test differences between pre- and posttraining values for BMC and total lean mass. Differences between increments were studied with the Student's t-test. Linear regression models were fitted to test independent relationships. RESULTS: After the intervention, higher increments in total and hip BMC, and total lean mass, were observed in the DS-E group (all p<0.05). A time × exercise interaction was found for total lean mass (p<0.05). The increment in total lean mass, height, and Tanner stage accounted for almost for 60% in the increment in total BMC in the DS-NE group (p<0.05). INTERPRETATION: Twenty-one weeks of training have a positive effect on the acquisition of bone mass in young people with Down syndrome.

A cross-sectional analysis of the association between physical activity, depression, and all-cause mortality in Americans over 50 years old.

Depression is estimated to be the second leading cause of disability in the United States and is associated with a 52% increased risk of death. Lifestyle components may have an important role in depression pathogenesis. The aims of this study were to analyze the association of meeting the physical activity (PA) recommendation guidelines and depression, and to analyze the all-cause mortality risk of the joint association of PA and depression. This cross-sectional study included 7201 participants from the 2007-2014 National Health and Nutrition Examination Survey aged ≥ 50 years and linked to National Death Index records through December 31, 2015. Depression was defined as a score ≥ 10 using the Patient Health Questionnaire (PHQ-9). PA was self-reported, and total PA was used to classify participants as more active (≥ 600 MET-min/week) or less active (< 600 MET-min/week). The odds ratios for depression were examined according to be more active or less active. The hazard ratios (HR) for the association of PA level and depression status with all-cause mortality were examined. Being more active was associated with reduced odds for depression. Compared with less active participants with depression, those who were more active and having depression had HR 0.45 (95% CI 0.22, 0.91, p = 0.026) for all-cause mortality. Being more active is associated with lower odds for depression and seems to be a protective factor against the increased all-cause mortality risk due to depression.