Do Serum 25-Hydroxyvitamin D Concentrations Affect Body Composition, Physical Fitness, Bone Strength and Bone Biomarkers in Female Children and Adolescent Football Players? A One-Season Study.

The aim was to compare changes in body composition, physical fitness, and bone biomarkers in female children and adolescent football players with different Vitamin D levels. Twenty-two players were classified into two groups according to 25(OH)D concentrations: 11 with deficient/insufficient 25(OH)D levels (IVD; <30 ng/mL) and 11 with sufficient 25(OH)D levels (SVD; ≥30 ng/mL). Body composition parameters were measured using dual-energy X-ray absorptiometry and a peripheral quantitative computed tomography scanner. The following physical fitness tests were applied: maximal isometric knee extension (MIF), long jump, 30-m sprint, and 20-m shuttle run test (VO2max). Electrochemiluminescence immunoassays were used to analyze bone biomarkers and 25(OH)D. All variables were registered at the beginning and the end of the football season. The increase in subtotal bone mineral density (BMD) was higher in players with SVD than those with IVD (p = 0.030). Only players with SVD improved their MIF of the left leg (p = 0.005); whereas, only players with IVD decreased their 30-m sprint performance (p = 0.007) and VO2max (p = 0.046). No significant between- and within-group differences were found for bone biomarkers. SVD might cause an extra improvement of subtotal BMD in female children and adolescent football players. Moreover, it seems that the 25(OH)D concentration could be an important parameter for physical fitness improvement in this population.

Effect of an Active Video Game Intervention Combined With Multicomponent Exercise for Cardiorespiratory Fitness in Children With Overweight and Obesity: Randomized Controlled Trial.

BACKGROUND: Childhood overweight and obesity have become major global health problems and are negatively related with the cardiorespiratory fitness (CRF) level in school children and adolescents. Exercise, specifically multicomponent training, is effective for CRF improvement, but the main challenge is to ensure adherence to exercise in children with overweight and obesity. Therefore, new ways of exercising that are more attractive and motivational for this population are needed and playing or training with active video games (AVGs) has been proposed as an effective alternative because they require full-body movement and therefore increase energy expenditure. OBJECTIVE: The main aim of this study was to investigate the effects of an AVG intervention combined with multicomponent training on CRF at maximal and submaximal intensities in children with overweight or obesity. METHODS: We recruited 28 children (13 girls and 15 boys) aged 9 to 11 years with overweight or obesity from medical centers and divided them into 2 groups, an intervention group (n=20) that participated in a 5-month supervised AVG exercise program combined with multicomponent exercise, and a control group (n=8) that continued daily activities without modification. A maximal stress test to measure CRF using a walking-graded protocol with respiratory gas exchange was performed by the participants. RESULTS: The AVG group showed a significant decrease in heart rate and oxygen uptake for the same intensities in the submaximal stages of the maximal treadmill test, as well as a lower oxygen uptake percentage according to the individual maximal oxygen uptake, whereas the control group did not show overall changes. No change in the peak oxygen uptake (VO2peak) was found. CONCLUSIONS: A 5-month AVG intervention combined with multicomponent exercise had positive effects on CRF at submaximal intensity, showing a lower heart rate and oxygen uptake at the same intensities and displaying a lower oxygen uptake percentage according to the individual (VO2peak). Greater benefits were found in children with the highest fat percentage. TRIAL REGISTRATION: ClinicalTrials.gov NCT04418713; https://clinicaltrials.gov/show/NCT04418713.

Active Video Games Improve Muscular Fitness and Motor Skills in Children with Overweight or Obesity.

(1) Background: Childhood obesity is an important public health problem. Children with overweight or obesity often tend to show the pediatric inactivity triad components; these involve exercise deficit disorder, pediatric dynapenia, and physical illiteracy. The aim of the study was to examine the influence of an active video games (AVG) intervention combined with multicomponent exercise on muscular fitness, physical activity (PA), and motor skills in children with overweight or obesity. (2) Methods: A total of 29 (13 girls) children (10.07 ± 0.84 years) with overweight or obesity were randomly allocated in the intervention group (AVG group; n = 21) or in the control group (CG; n = 8). The intervention group performed a 5-month AVG training using the Xbox 360® with the Kinect, the Nintendo Wii®, dance mats, and the BKOOL® interactive cycling simulator, combined with multicomponent exercise, performing three sessions per week. The control group continued their daily activities without modification. Weight, PA using accelerometers, and motor competence using the Test of Gross Motor Development 3rd edition were measured. Muscular fitness was evaluated through the Counter Movement Jump height, maximal isometric strength of knee extension and handgrip strength, and lean mass using Dual-energy X-ray Absorptiometry. Mann−Whitney U and Wilcoxon signed rank tests were performed. The biserial correlation coefficients (r) were calculated. Spearman's correlation coefficients among PA, muscular fitness, and motor competence variables were also calculated. (3) Results: The AVG group significantly increased their knee extension maximal isometric strength (4.22 kg; p < 0.01), handgrip strength (1.93 kg; p < 0.01), and jump height (1.60 cm; p < 0.01), while the control group only increased the knee extension maximal isometric strength (3.15 kg; p < 0.01). The AVG group improved motor competence and light physical activity (p < 0.05) and decreased sedentary time (p < 0.05). Lean mass improved in both AVG group and CG (p < 0.05). Lastly, the percentage of improvement of motor skills positively correlated with the percentage of improvement in vigorous PA (r = 0.673; p = 0.003) and the percentage of improvement in CMJ (r = 0.466; p = 0.039). (4) Conclusions: A 5-month intervention combining AVG with multicomponent training seems to have positive effects on muscle fitness, motor competence, and PA in children with overweight or obesity.

The Impact of Grounding in Running Shoes on Indices of Performance in Elite Competitive Athletes.

The introduction of carbon fiber plate shoes has triggered a plethora of world records in running, which has encouraged shoe industries to produce novel shoe designs to enhance running performance, including shoes containing conductor elements or "grounding shoes" (GS), which could potentially reduce the energy cost of running. The aim of this study was to examine the physiological and perceptual responses of athletes subjected to grounding shoes during running. Ten elite runners were recruited. Firstly, the athletes performed an incremental running test for VO2max and anaerobic threshold (AT) determination, and were familiarized with the two shoe conditions (traditional training shoe (TTS) and GS, the latter containing a conductor element under the insole). One week apart, athletes performed running economy tests (20 min run at 80% of the AT) on a 400 m dirt track, with shoe conditions randomized. VO2, heart rate, lactate, and perceived fatigue were registered throughout the experiment. No differences in any of the physiological or perceptual variables were identified between shoe conditions, with an equal running economy in both TTS and GS (51.1 ± 4.2 vs. 50.9 ± 5.1 mL kg-1 min-1, respectively). Our results suggest that a grounding stimulus does not improve the energy cost of running, or the physiological/perceptual responses of elite athletes.

Effects of Active Video Games on Health-Related Physical Fitness and Motor Competence in Children and Adolescents With Overweight or Obesity: Systematic Review and Meta-Analysis.

BACKGROUND: Childhood obesity is one of the most important public health problems. Active video games (AVGs) have been proposed as an attractive alternative to increase energy expenditure and are being investigated to determine their effectiveness against childhood obesity. OBJECTIVE: The aim of this study is to summarize the existing research and draw conclusions about the effects of AVGs on health-related physical fitness and motor competence in children and adolescents with overweight and obesity. METHODS: The search strategy was applied to PubMed, MEDLINE, Web of Science, and SPORTDiscus, including randomized and nonrandomized controlled trials investigating the effects of AVG programs on health-related physical fitness and motor competence in children and adolescents with overweight and obesity. To measure the risk of bias in randomized and nonrandomized controlled trials, 2 different quality assessment tools were used. In total, 15 articles met the inclusion criteria, and the variables of interest were BMI, body fat percentage, cardiorespiratory fitness (CRF), waist circumference, fat-free mass, muscular fitness, and motor competence. A meta-analysis was performed. RESULTS: Positive effects were found for BMI and body fat percentage, favoring the AVG group compared with a control group with no intervention (mean difference -0.209; 95% CI -0.388 to -0.031 vs mean difference -0.879; 95% CI -1.138 to -0.602). Positive effects seem to be observed for CRF. The effects of AVG interventions on muscular fitness, fat-free mass, waist circumference, and motor competence are unclear. CONCLUSIONS: AVG programs showed positive effects on BMI, body fat percentage, and CRF. AVG could be a good strategy to combat childhood obesity.

Establishing a Global Standard for Wearable Devices in Sport and Exercise Medicine: Perspectives from Academic and Industry Stakeholders.

Millions of consumer sport and fitness wearables (CSFWs) are used worldwide, and millions of datapoints are generated by each device. Moreover, these numbers are rapidly growing, and they contain a heterogeneity of devices, data types, and contexts for data collection. Companies and consumers would benefit from guiding standards on device quality and data formats. To address this growing need, we convened a virtual panel of industry and academic stakeholders, and this manuscript summarizes the outcomes of the discussion. Our objectives were to identify (1) key facilitators of and barriers to participation by CSFW manufacturers in guiding standards and (2) stakeholder priorities. The venues were the Yale Center for Biomedical Data Science Digital Health Monthly Seminar Series (62 participants) and the New England Chapter of the American College of Sports Medicine Annual Meeting (59 participants). In the discussion, stakeholders outlined both facilitators of (e.g., commercial return on investment in device quality, lucrative research partnerships, and transparent and multilevel evaluation of device quality) and barriers (e.g., competitive advantage conflict, lack of flexibility in previously developed devices) to participation in guiding standards. There was general agreement to adopt Keadle et al.'s standard pathway for testing devices (i.e., benchtop, laboratory, field-based, implementation) without consensus on the prioritization of these steps. Overall, there was enthusiasm not to add prescriptive or regulatory steps, but instead create a networking hub that connects companies to consumers and researchers for flexible guidance navigating the heterogeneity, multi-tiered development, dynamicity, and nebulousness of the CSFW field.

The Effects of Active Video Games on Health-Related Physical Fitness and Motor Competence in Children and Adolescents with Healthy Weight: A Systematic Review and Meta-Analysis.

(1) Background: Poor levels of physical fitness and motor skills are problems for today's children. Active video games (AVG) could be an attractive strategy to help address them. The aim was to investigate the effects of AVG on health-related physical fitness and motor competence in children and adolescents with healthy weight. (2) Methods: Randomized and non-randomized controlled trials investigating the effects of AVG programs on health-related physical fitness and motor competence were included. Two different quality assessment tools were used to measure the risk of bias. Twenty articles met the inclusion criteria and the variables of interest were body mass index (BMI), body fat, cardiorespiratory fitness (CRF), muscular fitness and motor competence. (3) Results: AVG interventions seem to have benefits in BMI when lasting longer than 18 weeks (SMD, -0.590; 95% IC, -1.071, -0.108) and in CRF (SMD, 0.438; 95% IC, 0.022, 0.855). AVG seems to be a promising tool to improve muscular fitness and motor competence but the effects are still unclear due to the lack of evidence. (4) Conclusions: AVG seem to be an effective tool for improving some components of health-related physical fitness and motor competence in healthy-weight children and adolescents, but the effect on some fitness components needs further research. Therefore, AVG may be included as a strategy to improve health.

Association Between Physical Fitness and Bone Strength and Structure in 3- to 5-Year-Old Children.

BACKGROUND: The positive association between physical fitness and bone structure has been widely investigated in children and adolescents, yet no studies have evaluated this influence in young children (ie, preschoolers). HYPOTHESIS: Fit children will present improved bone variables when compared with unfit children, and no sex-based differences will emerge in the sample. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: Handgrip strength, standing long jump (SLJ), speed/agility, balance, and cardiorespiratory fitness (CRF) were assessed using the Assessing FITness levels in PREschoolers (PREFIT) test battery in 92 children (50 boys; age range, 3-5 years). A peripheral quantitative computed tomography scan was performed at 38% of the length of the nondominant tibia. Cluster analysis from handgrip strength, SLJ, speed/agility, and CRF was developed to identify fitness groups. Bone variables were compared between sexes and between cluster groups. The association between individual physical fitness components and different bone variables was also tested. RESULTS: Three cluster groups emerged: fit (high values on all included physical fitness variables), strong (high strength values and low speed/agility and CRF), and unfit (low strength, speed/agility, and CRF). The fit group presented higher values than the strong and unfit groups for total and cortical bone mineral content, cortical area, and polar strength strain index (all P < 0.05). The fit group also presented a higher cortical thickness when compared with the unfit group (P < 0.05). Handgrip, SLJ, and speed/agility predicted all bone variables except for total and cortical volumetric bone mineral density. No differences were found for bone variables between sexes. CONCLUSION: The results suggest that global fitness in preschoolers is a key determinant for bone structure and strength but not volumetric bone mineral density. CLINICAL RELEVANCE: Physical fitness is a determinant for tibial bone mineral content, structure, and strength in very young children. Performing physical fitness tests could provide useful information related to bone health in preschoolers.

Establishing a Global Standard for Wearable Devices in Sport and Fitness: Perspectives from the New England Chapter of the American College of Sports Medicine Members.

The recent explosion of wearable technology and the associated concerns prompted the International Federation of Sports Medicine (FIMS) to create a quality assurance standard for wearable devices, which provides commissioned testing of marketing claims and endorsement of commercial wearables that test favorably. An open forum as announced in the conference advertising was held at the Annual Meeting of the New England Regional Chapter of the American College of Sports Medicine (NEACSM) November 7 to 8, 2019, in Providence, Rhode Island, USA for attending NEACSM members to voice their input on the process. Herein, we report the proceedings. The round table participants perceived the quality assurance standard to be important, but identified some practical process challenges that included the broad scope and complexity of the device universe, the need for a multiphase testing pathway, and the associated fees for product evaluation. The participants also supported the evaluation of device data analysis, behavioral influences, and user experience in the overall evaluation. Looking forward, the FIMS quality assurance standard faces the challenge of balancing these broader perspectives with practical constraints of budget, facilities, time, and human resources.

Long-Term Effects of Whole-Body Vibration in Trained Adolescent Swimmers: Does It Increase Strength, Power, and Swimming Performance?

PURPOSE: To examine the effects of a 6-month whole-body vibration (WBV) training on lower-body strength (LBS), lower-body power (LBP), and swimming performance in adolescent trained swimmers. METHODS: Thirty-seven swimmers (23 males and 14 females; 14.8 [1.3] y) were randomly assigned to the WBV (n = 20) or the control group (n = 17). Isometric LBS (knee extension and half squat) and LBP (vertical and horizontal jumps and 30-m sprint) tests were performed before and after the intervention period. Swimming performance times in 100 m were collected from official competitions. As time × sex interaction was not found for any variable (P > .05), males and females were analyzed as a whole. RESULTS: Within-group analyses showed a most likely beneficial moderate effect of WBV on isometric knee extension (effect size [ES] = 0.63), 30-m sprint test (ES = 0.62), and 100-m performance (ES = 0.25), although these were corresponded with comparable small to moderate effects in the control group (ES = 0.73, 0.71, and 0.20, respectively). The control group obtained a small possibly beneficial effect of swimming-only training on vertical jump performance, whereas no effect was observed in the WBV group. Unclear effects were observed for the rest of the variables assessed. Between-group analyses revealed unclear effects of WBV training when compared with the control condition in all studied variables. CONCLUSIONS: There is no current evidence to support the use of WBV training, and therefore, coaches and sports specialists should select other methods of training when the aim is to increase LBS, LBP, or swimming performance.

Is Playing Soccer More Osteogenic for Females Before the Pubertal Spurt?

The aims of this study were to assess bone mass in children and adolescent soccer players and to evaluate the influence of both gender and pubertal status on bone mass. A total of 110 soccer players (75 males / 35 females; 12.73 ± 0.65 / 12.76 ± 0.59 years) participated in this cross-sectional study. They were divided into two groups according to their pubertal status. Bone and lean masses were measured with Dual-energy X-ray Absorptiometry. An independent t-test and an adjusted by subtotal lean and training experience multivariate analysis of covariance were used to analyse the differences in bone mass values between genders and maturity status. Female soccer players presented higher bone mass values than their male counterparts in most of the measured weight-bearing sites. Moreover, when stratifying by pubertal status, peripubertal and postpubertal females had higher subtotal body and lumbar spine bone mass than males. Comparing between pubertal status groups before adjustment, both male and female postpubertal players showed higher bone mass than their pubertal counterparts. After adjusting, these differences disappeared and, in fact results were inverted as bone mass at the femoral neck was higher in both male and female peripubertal soccer players than in postpubertal players. Bone mass seems to be more intensely stimulated by playing soccer in female than male players, particularly in the lumbar spine. The results of peripubertal players showing higher bone mass at the femoral neck after adjusting suggest that playing soccer during the peripubertal stage could be an effective activity to achieve optimal bone mass values.

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.

Plantar pressures in male adolescent soccer players and its associations with bone geometry and strength.

BACKGROUND: Mechanical loads exerted by soccer-specific actions increase bone remodeling activity. Nevertheless, little is known about the relationship between plantar pressure and bone structure. Therefore, the aim of this study was to compare bone geometry and strength between soccer players who exhibited different maximum values of the average pressures (MP) when performing a combination of soccer-specific tasks. METHODS: Forty male adolescent soccer players (mean age 13.2±0.5 years) and 13 controls (mean age 13.1±0.9 years) participated in this study. Biofoot® system was used to measure MP at the non-dominant foot during a circuit of soccer-specific tasks. Cluster analysis was performed to classify players into groups of similar MP profiles resulting two different groups as follows: 15 players with high MP (SOC-HP; mean MP: 392.7±68.2 kPa) and 25 with low MP (SOC-LP; mean MP: 261.0±49.6 kPa). Total and cortical volumetric bone mineral content (Tt.BMC/Ct.BMC), cross-sectional area (Tt.Ar/Ct.Ar), cortical thickness (Ct.Th), fracture load in X-axis, and polar strength index (SSIp) were measured at 38% of the non-dominant tibia by peripheral quantitative computed tomography. Bone geometry and strength comparisons between SOC-HP and SOC-LP were performed using analyses of covariance controlling by weight and tibia length. RESULTS: Greater Tt.BMC, Ct.BMC and Tt.Ar. were found in SOC-HP compared to CG (Tt.BMC: 3.22vs2.95 g, Ct.BMC: 2.95vs2.68 g, Ct.Ar: 280vs253 mm2; P<0.05). Nevertheless, no significant bone geometry and strength differences were found between soccer groups and between SOC-LP and CG (P>0.05). CONCLUSIONS: Developing high MP when training and playing soccer might be favorable to bone development.

Bone geometry in young male and female football players: a peripheral quantitative computed tomography (pQCT) study.

The present study shows that football practice during growth may improve bone geometry in male and female football players. However, only females had better bone strength in comparison with controls. PURPOSE: The aim of this study was to compare bone geometry in adolescent football players and controls. METHODS: A total of 107 football players (71 males/36 females; mean age 12.7 ± 0.6/12.7 ± 0.6 years) and 42 controls (20 males/22 females; mean age 13.1 ± 1.4/12.7 ± 1.3 years) participated in this study. Total and trabecular volumetric bone mineral content (Tt.BMC/Tb.BMC), cross-sectional area (Tt.Ar/Tb.Ar), and bone strength index (BSI) were measured at 4% site of the non-dominant tibia by peripheral quantitative computed tomography (pQCT). Moreover, Tt.BMC, cortical BMC (Ct.BMC), Tt.Ar, cortical Ar (Ct.Ar), cortical thickness (Ct.Th), periosteal circumference (PC), endosteal circumference (EC), fracture load in X-axis, and polar strength strain index (SSIp) were measured at 38% site of the tibia. Multivariate analyses of covariance were used to compare bone pQCT variables between football players and controls using the tibia length and maturity offset as covariates. RESULTS: Female football players demonstrated 13.8-16.4% higher BSI, Ct.Th, fracture load in X-axis, and SSIp than controls (p < .0036). Males showed no significant differences in bone strength when compared to controls (p > .0036). In relation to bone mineral content and area, male football players showed 8.8% higher Tt.Ar and Tb.Ar at the 4% site of the tibia when compared to controls; whereas 13.8-15.8% higher Tt.BMC, Ct.BMC, and Ct.Ar at the 38% site of the tibia were found in female football players than controls (p < .0036). CONCLUSIONS: In this study, female adolescent football players presented better bone geometry and strength values than controls. In contrast, only bone geometry was higher in male football players than controls.

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.