Associations between Physical Fitness, Bone Mass, and Structure in Older People.

The main aim was to analyse the associations between several physical fitness variables and bone parameters in a sample of elderly people. 129 participants (94 females and 35 males, 76.2 ± 5.4 y) from the EXERNET cohort of Zaragoza (Spain) were included in the study. Physical fitness was assessed using the Senior Fitness Test Battery. Peripheral quantitative computed tomography (pQCT) at the tibia and dual-energy X-ray absorptiometry (DXA) at the hip and lumbar spine were used to assess bone and muscle parameters. Partial correlations were used to describe the associations between fitness and bone parameters. A stepwise regression analysis was used to determine the influence of fitness variables on bone parameters. In males, significant correlations were found between lower body strength and agility with bone total mineral density (Tt.BMD) (r = 0.41 and -0.50) and cortical thickness (r = 0.40 and -0.50, respectively) and walking speed with total and cortical density (r = -0.41 and -0.40, respectively), all measured at tibia (all p < 0.05). Regarding DXA, neck areal bone mineral density (aBMD) correlated with flexibility (r = -0.37) and walking speed (r = 0.39) and Ward's triangle with walking speed (r = 0.39). Agility predicted Tt.BMD and cortical thickness (r 2 change = 24.8% and 23.0%), while walking speed predicted cortical bone mineral density (r 2 change = 19.5%) (all p < 0.05). Females showed correlations between balance and total hip aBMD (r = 0.27) and trochanter aBMD (r = 0.25). Balance predicted trochanter (r 2 change = 4.2%) and total hip aBMD (r 2 change = 4.9%) (both p < 0.05). In conclusion, bone mass in elderly males seems to be more influenced by physical fitness than in females, being agility and walking speed the variables showing greater associations. Other variables should be taken into account in females for future research.

Is Sitting Time Related with Physical Fitness in Spanishelderly Population? The EXERNET Multicenter Study.

BACKGROUND: Older adults spend most of their waking hours performing sedentary activities. The influence of these lifestyle patterns on the physical fitness (PF) levels of this population has not yet been sufficiently investigated. OBJECTIVE: The aim of the study was to examine whether sedentary behavior (SB) (h•d-1sitting) is associated with PF, and specifically to analyze whether sitting >4 h•d-1 is associated with higher risk of having lower levels of fitness in seniors. DESIGN: EXERNET multi-center study. PARTICIPANTS AND SETTINGS: A representative sample of 3136 non-institutionalized elderly (aged 72.2±5.3 years), from 6 Regions of Spain were included in the study. MEASUREMENTS: PF was assessed using 8 different tests from the EXERNET battery. Lifestyle patterns were collected using a validated questionnaire. ANOVA was used to compare the groups according to the hours of sitting. Binary logistic regression was used to calculate the association between the SB and low levels of fitness. RESULTS: For both genders, those who spent sitting >4 h•d-1 had lower levels of balance, agility, walking speed and aerobic endurance (p<0.001). Sedentary men also had less strength of lower extremities (p<0.05), whereas, sedentary women were less flexible in the lower extremities (p<0.001). More than 4 h•d-1 sitting was associated, in men, to higher odds for having low strength (lower extremities), agility, flexibility (lower extremities) and aerobic endurance (p<0.05); and in women, to higher risk of low balance, strength (lower and upper extremities), flexibility (lower extremities), agility, walking speed and aerobic endurance (p<0.05). CONCLUSIONS: Seniors that sit >4 h•d-1 have lower levels of fitness and this behavior is related with an increased risk of having low levels of PF in this population.

The muscle-bone unit in adolescent swimmers.

Most researchers adjust bone by lean mass when comparing swimmers with controls. This adjustment is done under the assumption that lean affects bone similarly in both groups. Nonetheless, we found that the muscle-bone association is uncoupled in swimmers, and consequently, researchers should avoid this adjustment when evaluating swimmers' bone. INTRODUCTION: To examine the functional and structural muscle-bone unit in adolescent swimmers. METHODS: Sixty-five swimmers (34 girls/31 boys) and 119 controls (51 girls/68 boys) participated in the study. Muscle cross-sectional area (MCSA), bone mineral content (BMC), and polar strength-strain index (SSIPOL) were measured in the non-dominant radius by peripheral quantitative computed tomography (pQCT). Subtotal BMC and lean mass were evaluated with dual-energy X-ray absorptiometry (DXA). Handgrip and isometric knee extension (IKE) tests were performed to determine muscle force. The effect of MCSA, lean and force on SSIPOL, and BMC were tested, and the functional and structural muscle-bone ratios of swimmers and controls were compared. RESULTS: Both muscle size (MCSA and lean) and muscle force (handgrip and IKE) influenced BMC and SSIPOL in swimmers and controls similarly. Swimmers presented normal MCSA and lean values for their height, but when compared with controls, swimmers presented a higher amount of lean and MCSA for the same BMC or SSIPOL (structural muscle-bone unit). For the functional muscle-bone unit, different results were found for the lower and upper limbs, as no differences were found for the upper limbs, while for the lower limbs, swimmers presented higher muscle force for the same amount of BMC. CONCLUSIONS: The contradictory results regarding BMC in swimmers found in previous studies could partly be explained with the findings of the present study that reinforce the idea that swimming is not an effective sport to practice regarding bone mass and that the muscle-bone unit is different in swimmers than in controls.

Vigorous physical activity patterns affect bone growth during early puberty in boys.

This study aims to analyze the impact of participation in vigorous physical activity as it can promote a healthy bone development. Adolescents who increased their participation in vigorous physical activity showed higher improvements in bone parameters compared to those who did not, which highlights the relevance of vigorous physical activity engagement. INTRODUCTION: The main purpose of the study was to analyze the effects of different patterns of vigorous physical activity (VPA) on bone development. METHODS: One-week accelerometry registers and dual-energy X-ray absorptiometry scans at the whole body, hip, and lumbar spine of 140 healthy male adolescents (11-13 years, at baseline) were performed twice with a 1-year interval between measurements. Four patterns of VPA evolution ("low-low," "low-high," "high-low," and "high-high") and three patterns of bone growth ("optimal," "mean," and "reduced") were defined according to the median participation in VPA and a cluster analysis of the longitudinal changes in BMC and BMD in all sites measured, respectively. Bone mineral parameters were adjusted for skeletal age and body weight prior to statistical comparison among groups. RESULTS: Participants in the "low-high" group had greater adjusted BMD increases at both the femoral neck and lumbar spine when compared to the "low-low" group (estimated mean (95% CI) 0.066 (0.047-0.085) vs. 0.034 (0.021-0.047) g/cm2 and 0.074 (0.054-0.093) vs. 0.049 (0.035-0.062) g/cm2 respectively, both p < 0.05). Femoral neck BMD adjusted increase was also different between the "high-high" and the "high-low" groups (0.053 (0.041-0.066) vs. 0.030 (0.011-0.049) g/cm2, p < 0.05). Additionally, a higher percentage of "optimal" growth was found in the "low-high" group than in the "low-low" and "high-low" categories (36.3, 12.5 and 13.6% respectively, p < 0.05). CONCLUSIONS: Engaging in VPA as well as maintaining high levels of VPA during puberty is associated with greater gains in bone mass, which can have an impact in future bone health.

Mediterranean diet, diet quality, and bone mineral content in adolescents: the HELENA study.

Dietary scores, rather than individual nutrients, allow exploring associations between overall diet and bone health. The aim of the present study was to assess the associations between the Mediterranean Diet Score for Adolescents (MDS-A) and the Diet Quality Index for Adolescents (DQI-A) and bone mineral content (BMC) among Spanish adolescents. Our results do not support an association between dietary scores or indices and BMC in adolescents. INTRODUCTION: To assess the associations between the MDS-A and a DQI-A with the BMC measured with dual-energy X-ray absorptiometry. METHODS: The MDS-A and the DQI-A were calculated in 179 Spanish adolescents, based on two 24-h dietary recalls from the HELENA cross-sectional study. The associations between the diet scores and the BMC outcomes [total body less head (TBLH), femoral neck (FN), lumbar spine (LS), and hip] were analyzed using logistic regression models adjusting for several confounders. RESULTS: Four hundred ninety-two models were included and only fruits and nuts and cereal and roots were found to provide significant ORs with regard to BMC. The risk of having low BMC reduced by 32% (OR 0.684; CI 0.473-0.988) for FN when following the ideal MDS-A, but this association lost significance when adjusting for lean mass and physical activity. For every 1-point increase in the cereal and root and the fruit and nut components, the risk of having low FN diminished by 56% (OR 0.442; CI 0.216-0.901) and by 67% (OR 0.332; CI 0.146-0.755), respectively. CONCLUSION: An overall dietary score or index is not associated with BMC in our adolescent Spanish sample.

[Relation between educational level and body composition in non-institutionalized elderly: The elderly EXERNET multi-center study.] / Relación entre el nivel educativo y la composición corporal en personas mayores no institucionalizadas: proyecto multi-céntrico EXERNET.

OBJECTIVE: There is an inverse association between educational level and body composition; however this association has strongly focused in young and adults population. The aim of this study was to analyze the educational levels attained in overweight and obesity Spanish elderly and to investigate if there was a correlation between having a low educational level and the risk of having overweight, central obesity or excess fat mass during the aging process. METHODS: A representative sample of 2706 elderly (629 men and 2077 women; mean age of 72.1 ± 5.3 years) from Spain were assessed in the elderly EXERNET multi-center study between 2008 and 2009. Body composition was assessed in all subjects by bioelectrical impedance. ANCOVA was used to compare the averages between the groups. Logistic regression was used to calculate the association between educational level and the risk of having overweight, central fat or obesity. RESULTS: We observed significances between waist circumference and educational level in both sex (men 96.6 cm, women 86.3 cm); (p less than 0.05 and p less than 0.01, respective). There is an inverse association between the academic level, fat mass (29.5 kg) and percentage of body fat (40.8%) in women (p less than 0.05, p less than 0.01, respectively). No differences were observed in men. CONCLUSIONS: low educational level increases the possibility of having overweight or obesity in women and to have an increased waist circumference in both sexes.

OBJETIVO: El nivel educacional se ha relacionado inversamente con la composición corporal, sin embargo esta asociación ha sido evidenciada mayoritariamente en población joven y adulta. El objetivo del presente estudio fue evaluar la relación entre la composición corporal de las personas mayores de 65 años y su nivel educativo, y determinar si tener un nivel educativo alto puede prevenir el riesgo de padecer sobrepeso, obesidad central o exceso de grasa durante la senectud. METODOS: El estudio se realizó entre los años 2008-2009, sobre una muestra representativa de personas mayores de España (2.706; 629 varones, 2.077 mujeres; edad media 72,1 ± 5,3 años), pertenecientes al Proyecto Multi-céntrico EXERNET. La composición corporal se evaluó mediante bio-impedancia eléctrica. Se utilizó ANCOVA para determinar las diferencias entre grupos. La asociación entre el nivel educativo y el riesgo de padecer sobrepeso, obesidad central o exceso de grasa se analizó mediante regresión logística. RESULTADOS: En el perímetro de cintura, los hombres y mujeres con mayor nivel de estudios presentaron 96,6 cm y 86,3 cm, respectivamente (pmenor de 0,05 y p menor de 0,01, respectivamente). Las mujeres con menor nivel de estudios presentaron 29,5 kg de masa grasa total y 40,8% de masa grasa (p menor de 0,05 y p menor de 0,01, respectivamente). Los varones no presentaron diferencias en estas mediciones. CONCLUSIONES: Poseer un bajo nivel de estudios aumenta las posibilidades de padecer sobrepeso y obesidad en las mujeres y de tener mayor perímetro de cintura en ambos sexos.

Do 6 months of whole-body vibration training improve lean mass and bone mass acquisition of adolescent swimmers?

Swimming has little effect on bone mass. Therefore, adolescent swimmers should complement their water training with a short and intense weight-bearing training, aiming to increase their bone acquisition. Forty swimmers performed a six-month whole-body vibration (WBV) training. WBV had no effect on adolescent swimmers' bone mass or lean mass. PURPOSE: The aims of the present study were to evaluate the effects of a whole-body vibration (WBV) intervention on bone mineral density (BMD), bone mineral content (BMC) and lean mass (LM) in adolescent swimmers. METHODS: Forty male and female adolescent swimmers (VIB; mean age 14.2 ± 1.9 years) completed the WBV protocol that consisted of 15 min of training 3 days per week during a 6-month period (ranging from 3.6 to 11.6 g), while 23 swimmers (SWI; mean age 15.0 ± 2.2 years) continued with their regular swimming training alone. VIB were divided into tertiles according to training compliance in order to evaluate if any dose-effect relation existed. BMD, BMC and LM were measured longitudinally by dual energy X-ray at the whole body, lumbar-spine and hip. RESULTS: No group by time interactions and no differences in change percentage were found for BMD, BMC or LM in any of the measured variables. The mean change percentage of the subtotal body (whole body minus the head) for VIB and SWI, respectively, was 2.3 vs. 2.4% for BMD, 5.7 vs 5.7% for BMC and 7.3 vs. 8.0% for lean mass. Moreover, no indication for dose-response was observed. CONCLUSIONS: The proposed WBV protocol had no effect on BMD, BMC and LM in adolescent swimmers. Other types of training should be used in this population to improve both bone and lean mass.

Higher bone mass in prepubertal and peripubertal female footballers.

OBJECTIVES: The main aim of this study was to compare the bone mass of female football players with controls of different pubertal stages. METHODS: Sixty five girls aged 8-14 years (10.14 ± 0.1, Tanner stages I-IV) participated in the study. Twenty participants were prepubertal (10 prepubertal control) and 45 peripubertal (15 peripubertal control). All footballers trained two days per week while the control group did not perform regular physical activity outside of school. Body composition was assessed by Dual-energy X-ray absorptiometry. Analysis of covariance was performed to evaluate differences in lean and bone masses. RESULTS: Significant differences in lower-body extremities lean mass (LLM) between peripubertal groups were found (P < .05). Additionally, prepubertal footballers showed higher values of bone mineral content (BMC) at the femoral neck (P < .05) while peripubertal footballers exhibited enhanced BMC at the whole-body, trochanter and Wards triangle area. Bone mineral density (BMD) was higher in footballers compared to their non-active peers at the femoral neck and intertrochanter (P < .05, respectively) while in the peripubertal footballers higher BMD values were found in almost all of the studied body sites. CONCLUSION: Female footballers showed higher bone and lean masses compared to control counterparts; these differences are already detectable at prepubertal ages and more consistent after pubertal spurt.

Effect of whole-body vibration training on bone mass in adolescents with and without Down syndrome: a randomized controlled trial.

UNLABELLED: Whole-body vibration training (WBV) attracts great interest as osteoporosis prevention strategy. Twenty-six adolescents with and without Down syndrome (DS) (13 DS; 12-18 years) performed 20 weeks of WBV. The results indicate that WBV seems to provoke a lesser response in adolescents with DS than in those without DS. INTRODUCTION: This study aims to observe the differences between adolescents with and without DS in the effects of 20 weeks of WBV training, on bone mineral content (BMC) and density (BMD). METHODS: Twenty-six adolescents (13 DS; 12-18 years) were measured with dual-energy X-ray absorptiometry before and after the intervention (3/week, 10 repetitions (30-60 s) and 1-min rest, frequency 25-30 Hz and peak-to-peak displacement of 2 mm (peak acceleration 2.5-3.6 g)). Both, an intention-to-treat (ITT) analysis designed to assess the effects on bone mass and a per-protocol analysis, designed to compare poor and high compliers, were performed. RESULTS: The ITT analysis revealed significant increases in all BMC and BMD parameters (dz = 0.66 to 1.64; all p < 0.05) in the non-DS group, whilst DS group improved whole-body, subtotal (whole-body less head), upper limbs (ULIMBS), pelvis, lower limbs (LLIMBS) and spine BMC (dz = 0.75 to 1.76; all p < 0.05) and subtotal, pelvis, LLIMBS and spine BMD (dz = 0.73 to 1.28; all p < 0.05). Significantly greater increases were evident in the absolute and percent changes of the non-DS group over DS group (d = 0.88 to 3.85; all p < 0.05). ULIMBS BMD showed a tendency towards an interaction (f = 0.41 and p = 0.086) with higher increase for non-DS group. When a per-protocol analysis was considered, high-complier adolescents had 8.1 versus 5.3 % of gains in the spine BMC over poor-complier adolescents (d = 0.93; p < 0.05). CONCLUSIONS: Twenty weeks of WBV training may improve BMC and BMD in clinically relevant skeletal sites in both groups. Nevertheless, this type of training seems to provoke a lesser response in adolescents with DS than in those without DS.

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

UNLABELLED: Swimming during adolescence has shown neutral or even negative effects on bone mass. Nevertheless, it is still unknown if these effects are due to swimming or to other factors, such as sedentary behaviors. INTRODUCTION: Three objectives were described (1) to measure objective physical activity (PA) additional to swimming performed by adolescent swimmers (SWI) and compare it to that performed by normo-active controls (CG), (2) to describe the relationship between objectively measured PA and bone mass, and (3) to compare bone mass of swimmers that meet the World Health Organization PA guidelines (active) WHO and those that do not (inactive). METHODS: A total of 71 SWI (33 females) and 41 CG (17 females) wore an accelerometer for at least 4 days. PA was expressed as the amount of time (minutes/day) in each intensity [sedentary/light/moderate or vigorous (VPA), and the sum of moderate and vigorous (MVPA)]. Using the cutoff points proposed by Vanhelst et al. SWI were classified as active or inactive according to whether they reached 60 min of weight-bearing MVPA per day or not. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry, and bone strength values were calculated with peripheral quantitative computed tomography. Differences in PA intensities were calculated between SWI and CG. The relation of VPA to bone mass was studied in the SWI. RESULTS: Male-SWI spend less time in VPA and MVPA than male-GC, which partly explains the lower BMD values in SWI than CG. CONCLUSION: Swimming may displace weight-bearing VPA with serious implications on bone health.

Bone structure of adolescent swimmers; a peripheral quantitative computed tomography (pQCT) study.

OBJECTIVES: The aims of the present study were: (1) to characterize vBMD, bone structure and strength with peripheral quantitative computerized tomography (pQCT) in adolescent swimmers and compare it to normo-active controls (CG); and (2) to evaluate the possible interaction that weight-bearing sports might have on swimmers bone. DESIGN: Cross-sectional. METHODS: The non-dominant radius and tibia of 79 (32 females) swimmers and 49 (22 females) CG (both 11-18 years old) were evaluated at proximal and distal sites with a pQCT scanner. Values of total, trabecular and cortical volumetric bone mineral density (vBMD) were obtained from each scan. Cortical thickness, endosteal and periosteal circumferences were also measured and bone strength indexes were calculated. Analyses of covariance were used to compare variables between groups adjusting for age, tanner stage and bone length. Three different analyses were performed according to present and past sport participation in addition to swimming in order to determine differences among swimmers who had performed or were performing other sports (OTHER-SP) (10 females/17 males) and swimmers who had not performed other sports (NO-OTHER-SP) (22 females/22 males). Both of these groups were compared to each other and to a CG (22 females/27 males). RESULTS: No differences were found between swimmers and CG for bone strength indexes, structure or vBMD (independently of the compared sample). CONCLUSIONS: These results indicate that swimmers present similar bone strength and structure than CG who did not present high physical activity levels.

Effect of whole body vibration training on bone mineral density and bone quality in adolescents with Down syndrome: a randomized controlled trial.

UNLABELLED: Adolescents with Down syndrome (DS) have poorer bone health than their peers without DS. Twenty-five adolescents with DS were randomly assigned to whole-body vibration training (WBV) or control groups. The results indicate that a 20-week WBV might be useful to improve subtotal bone mineral content and density in adolescents with DS. INTRODUCTION: This study aims to determine the effects of 20 weeks of whole body vibration training (WBV) on bone mineral content (BMC), density (BMD), and structure variables in adolescents with Down syndrome (DS). METHODS: This randomized controlled trial of 25 adolescents (12-18 years) with DS (8 females) generated 2 non-equal groups, WBV group (n = 11) and CON group (n = 14). Using an efficacy analysis, the primary outcomes were BMC and BMD by dual-energy X-ray absorptiometry and the secondary were bone structure variables by peripheral quantitative computed tomography. A synchronous vibration platform (PowerPlate®) was used (3/week, 10 repetitions (30-60 s) 1-min rest, frequency of 25-30 Hz, and peak-to-peak displacement of 2 mm (peak acceleration 2.5-3.6 g)). RESULTS: WBV group improved whole body BMC 2.8%, 95% CI [3.5, 2.1], subtotal area, BMC, and BMD by 2.8, 4.8, and 2%, respectively, 95% confidence intervals (CIs) [3.4, 2.1], [6.5, 3.1], and [2.8, 1.1], respectively (all, p < 0.05), showing group by time interactions in BMC and BMD (both p < 0.05). Lumbar spine BMC and BMD also increased in the WBV group by 6.6 and 3.3% both p < 0.05, 95 % CIs [8.6, 4.7], and [4.9, 1.7], respectively. Regarding bone structure, WBV group showed improvements in tibial BMC at 4 % (2.9 %, 95 % CI [3.0, 2.8]) and in volumetric BMD (vBMD), cortical vBMD, and cortical thickness at 66% of the radius (by 7.0, 2.4, and 10.9%; 95% CIs [7.4, 6.7], [2.6, 2.3], and [12.4, 9.3], respectively) (all, p < 0.05). CONCLUSIONS: A 20-week WBV, with this protocol, might be useful to improve subtotal BMC and BMD in adolescents with DS.

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

CONTEXT: Osteoporosis is a major public health concern worldwide. Understanding the roles of diet and physical activity in ensuring adequate bone mass accrual during childhood and adolescence may help identify strategies to reduce the risk of osteoporotic fractures later in life. OBJECTIVE: The present systematic review was conducted to provide an overview of the current knowledge of the combined effects of physical activity and diet on bone mass accrual in children and adolescents. DATA SOURCES: Data were obtained via searches of the PubMed, EMBASE, SPORTDiscus, and ISI Web of Science databases. STUDY SELECTION: Studies published in English and Spanish between 1887 and August 2013 were eligible for inclusion. Two investigators evaluated the studies against the inclusion and exclusion criteria. A total of 14 studies (7 cross-sectional and 7 experimental) were included in the review. DATA EXTRACTION: The Pedro score and the Black and Down's checklist were used to evaluate the methodological quality of the experimental and the cross-sectional studies, respectively. Study characteristics were summarized in accordance with the review's PICO criteria. DATA SYNTHESIS: Significant exercise-by-calcium interaction was detected at several different bone sites. CONCLUSIONS: Although the results of cross-sectional studies were inconsistent, the results of randomized controlled trials showed that exercise has the potential to improve bone health under conditions of adequate calcium intake.

The effects of swimming training on bone tissue in adolescence.

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

Physical fitness, overweight and the risk of eating disorders in adolescents. The AVENA and AFINOS studies.

UNLABELLED: What is already known about this subject Eating disorders are among the public health issues facing adolescents. An excess of body fat has been associated with an increased risk of these disorders. The association of physical fitness with eating disorders has not yet been analysed in adolescents. What this study adds This study confirms that the overweight and obesity increase the risk of developing eating disorders. The present study shows that there is an inverse association between physical fitness levels and the risk of eating disorders. This study suggests that physical fitness might attenuate the influence of overweight on the development of eating disorders in adolescents. BACKGROUND: Eating disorders together with the overweight and obesity are important health concerns in adolescents. OBJECTIVE: To analyse the individual and combined influence of overweight and physical fitness on the risk of developing eating disorders in Spanish adolescents. METHODS: The sample consisted of 3571 adolescents (1864 females), aged 13 to 18.5 years, from Spain who participated in the AVENA and AFINOS studies. The risk of eating disorders was evaluated using the SCOFF questionnaire. Body mass index was calculated and the adolescents were classified into two groups: overweight (including obesity) and non-overweight according to Cole's cut-off points. Cardiorespiratory fitness in the AVENA Study was assessed by the 20-m shuttle-run test and the overall physical fitness level was self-reported in the AFINOS Study. RESULTS: Overweight adolescents had a higher risk of developing eating disorders than non-overweight adolescents (odds ratio [OR] = 4.91, 95% confidence interval [CI]: 3.63-6.61 in the AVENA Study and OR = 2.45, 95% CI: 1.83-3.22 in the AFINOS Study). Also, adolescents with medium and low levels of physical fitness had a higher risk of developing eating disorders (OR = 1.51, 95% CI: 1.05-2.16, and OR = 2.25, 95% CI: 1.60-3.19, respectively, in the AVENA Study, and OR = 1.73, 95% CI: 1.37-2.17, and OR = 4.11 95% CI: 2.98-5.65, respectively, in the AFINOS Study) than adolescents with high levels of physical fitness. In both studies, the combined influence of overweight and physical fitness showed that adolescents with lower levels of physical fitness had an increased risk of developing eating disorders in both non-overweight and overweight groups. CONCLUSIONS: Physical fitness might attenuate the influence of overweight on the development of eating disorders in adolescents.

Influence of hard vs. soft ground surfaces on bone accretion in prepubertal footballers.

Information regarding osteogenic effects of physical activity performed on different playing surfaces is scarce. A total of 42 children (9.2±0.2 years, Tanner stages I-II) participated in this study. 14 were playing on artificial turf soft ground (SG), 14 on a natural non-grass hard ground (HG) and 14 were assigned to the sedentary control group (C). Whole body and hip scans (dual energy X-ray absorptiometry), anthropometric variables (weight and height) and physical fitness (VO2max) were determined in all participants. Bone mineral content (BMC) values were higher in the SG group compared to the C group at the legs (209.75±5.11 g vs. 187.42±5.14 g, respectively), pelvis (122.72±4.27 g vs. 98.58±4.29 g respectively) and whole-body level (1 126.1±22.81 g vs. 1 035.34±22.92 g, respectively). The hard ground (HG) group also showed higher values in the majority of BMC variables compared to the C group. Additionally, bone mineral density (BMD) was significantly higher at all sites of the hip in both active groups compared to control (P<0.05). No differences between HG and SG were found. In summary, similar bone mass accretion is obtained by prepubescent footballers independently of the surface on which they practice football.

Do calcium and vitamin D intake influence the effect of cycling on bone mass through adolescence?

INTRODUCTION: Cycling has been associated with decreased bone mass during adolescence. Calcium (Ca) and vitamin D (VitD) intake are associated to bone mass and may be important confounders when studying bone mass. AIM: To clarify the effect that Ca and VitD may have on bone mass in adolescent cyclists. METHODS: Bone mineral content (BMC) and density (BMD) of 39 male adolescents (20 cyclists) were measured. Ca and VitD intake were also registered. Different ANCOVA analyses were performed in order to evaluate the influence of Ca and VitD on BMC and BMD. RESULTS: Cyclists showed lower values of BMC and BMD than controls at several sites and when adjusting by Ca, Wards triangle BMD appeared also to be lower in cyclists than controls. CONCLUSION: Nutritional aspects might partially explain differences regarding bone mass in adolescent cyclists and should be taken into account in bone mass analysis as important confounders.

Introducción: El ciclismo se ha asociado con un descenso de la masa ósea durante la adolescencia. La ingesta de calcio (Ca) y vitamina D (VitD) repercute sobre la masa ósea llegando a ser factores de confusión importantes al estudiarla. Objetivo: Clarificar el efecto que el Ca y la VitD pueden tener sobre la masa ósea de ciclistas adolescentes. Métodos: se midió el contenido mineral óseo (CMO) y la densidad mineral ósea (DMO) de 39 varones adolescentes (20 ciclistas). También se registró la ingesta de Ca y VitD. Se realizaron distintos análisis ANCOVA para evaluar la influencia del Ca y la VitD sobre el CMO y la DMO. Resultados: Los ciclistas mostraron menores valores de CMO y DMO que los controles en diversas zonas y, cuando se ajustó por Ca, la DMO del triángulo de Wards también pasó a ser menor en los ciclistas que en los controles. Conclusión: Los aspectos nutricionales podrían explicar en parte las diferencias de masa ósea en ciclistas adolescentes y deberían tenerse en cuenta en el análisis de masa ósea como factores de confusión importantes.

Physical activity and cardiorespiratory fitness in adolescents with Down syndrome.

AIMS: To determine if adolescents with and without Down syndrome (DS) accomplish the physical activity (PA) guidelines and to evaluate relationships between PA and cardiorespiratory variables. METHODS: 42 adolescents (27 with DS) participated in this study. PA was measured using accelerometers. Walking-graded treadmill protocol with a breath-by-breath gas analyzer was employed to assess cardiorespiratory fitness. RESULTS: Adolescents with DS spent less time in sedentary PA, moderate PA (MPA), vigorous PA (VPA) and moderate to vigorous PA (MVPA) than those without DS. VO2peak was correlated with total minutes spent in light PA, MPA, VPA and MVPA in the control group (from r = 0.55 to r = 0.61, p < 0.05) and with MPA and MVPA in the DS group (from r = 0.38 to r = 0.41, p < 0.05). CONCLUSION: Nor DS neither control groups achieved at least 60 minutes of MPA daily. Engaging more time in MPA was associated with greater cardiorespiratory fitness in adolescents with DS.

Objetivos: Comprobar si los adolescentes con síndrome de Down (SD) cumplen las guías de actividad física (AF) y evaluar la relación entre AF y la condición cardiorrespiratoria. Métodos: 42 adolescentes (27 con SD) participaron en este estudio. La AF se midió usando acelerometría. La condición cardiorrespiratoria se evaluó mediante ergoespirometría en tapiz rodante con un protocolo progresivo continuo. Resultados: Los adolescentes con SD pasaron menos tiempo en AF sedentaria, moderada (MAF), vigorosa (VAF) y moderada-vigorosa (MVAF) que los adolescentes sin SD. El VO2peak mostró correlación con minutos totales en AF ligera, MAF, VAF y MVAF en el grupo control (desde r = 0,55 hasta r = 0,61, p < 0,05) y con MAF y VAF en el grupo de adolescentes con SD (desde r = 0,38 hasta r = 0,41, p < 0,05). Conclusión: Ningún grupo alcanzó 60 minutos de MAF diaria. La capacidad cardiorrespiratoria en adolescentes con SD se asoció con una mayor participación en MAF.

The nutritional status in adolescent Spanish cyclists.

INTRODUCTION: Adolescence is an important period of nutritional vulnerability due to the increased dietary requirements. OBJECTIVE: To describe the nutritional status of adolescent cyclist and a group of normoactive controls. METHODS: The HELENA Dietary Assessment Tool was used to evaluate the nutritional intake of 20 adolescent cyclists and 17 controls. Total energy intake, resting energy expenditure (REE), total energy expenditure (TEE), macronutrients and several micronutrients were registered and compared with dietary guidelines. RESULTS: REE was lower and TEE higher in cyclists than in controls (both P < 0.01). Significant differences were observed in phosphorus and vitamin B1 being higher in cyclists (P < 0.05). Most participants, both cyclist and controls, did not reach the diet requirements for macronutrients, vitamins and minerals. CONCLUSION: Nutritional status of adolescent cyclists and controls seems not to fulfil the requirements in quantity and quality. Possible implications for actual and future health especially in athlete adolescents need further research.

Introducción: La adolescencia es un periodo importante de vulnerabilidad nutricional dados las mayores demandas alimentarias. Objetivo: Describir el estado nutritivo de ciclistas adolescentes y de un grupo de controles con actividad normal. Métodos: Se utilizó la Herramienta de Evaluación Alimentaria HELENA para evaluar la ingesta nutricional de 20 ciclistas adolescentes y 17 controles. Se registraron la ingesta total de energía, el gasto de energía en reposo (GER), el gasto de energía total (GET), los macronutrientes y diversos micronutrientes y se compararon con las guías dietéticas. Resultados: El GER fue menor y el GTE mayor en los ciclistas que en los controles (ambos P < 0,01). Se observaron diferencias significativas en el fósforo y la vitamina B1, siendo mayores en los ciclistas (P < 0,05). La mayor parte de los participantes, tanto ciclistas como controles, no alcanzó los requerimientos en macronutrientes, vitaminas ni minerales. Conclusión: El estado nutritivo de los adolescentes ciclistas y de los controles parece no adecuarse a las recomendaciones de cantidad y calidad. Deberían investigarse las posibles implicaciones de la salud actual y futura, especialmente en los adolescentes atletas.

Validation of anthropometry and foot-to-foot bioelectrical resistance against a three-component model to assess total body fat in children: the IDEFICS study.

OBJECTIVE: To compare different field methods for estimating body fat mass with a reference value derived by a three-component (3C) model in pre-school and school children across Europe. DESIGN: Multicentre validation study. SUBJECTS: Seventy-eight preschool/school children aged 4-10 years from four different European countries. METHODS: A standard measurement protocol was carried out in all children by trained field workers. A 3C model was used as the reference method. The field methods included height and weight measurement, circumferences measured at four sites, skinfold measured at two-six sites and foot-to-foot bioelectrical resistance (BIA) via TANITA scales. RESULTS: With the exception of height and neck circumference, all single measurements were able to explain at least 74% of the fat-mass variance in the sample. In combination, circumference models were superior to skinfold models and height-weight models. The best predictions were given by trunk models (combining skinfold and circumference measurements) that explained 91% of the observed fat-mass variance. The optimal data-driven model for our sample includes hip circumference, triceps skinfold and total body mass minus resistance index, and explains 94% of the fat-mass variance with 2.44 kg fat mass limits of agreement. In all investigated models, prediction errors were associated with fat mass, although to a lesser degree in the investigated skinfold models, arm models and the data-driven models. CONCLUSION: When studying total body fat in childhood populations, anthropometric measurements will give biased estimations as compared to gold standard measurements. Nevertheless, our study shows that when combining circumference and skinfold measurements, estimations of fat mass can be obtained with a limit of agreement of 1.91 kg in normal weight children and of 2.94 kg in overweight or obese children.