Secular trends in the physical fitness of Brazilian youth: Evidence that fitness is declining for the majority but not for a fit minority.

BACKGROUND: There has been a decline in children's physical fitness in recent decades. Such concerns are largely based on evidence from North America, Europe, and Asia. The current study describes the secular trend and variation (spread) in the physical fitness scores of young Brazilians from 2005 to 2022. METHODS: This study is a repeated, cross-sectional surveillance study (1999-2022). Children and adolescents (n = 65 139; boys = 36 539) participated between 2005 and 2022. In each cohort six physical fitness tests were conducted: (1) 20-m sprint speed (m s-1 ), (2) cardio-respiratory 6-min run test (m min-1 ), (3) abdominal strength test (sit-ups per min), (4) horizontal jump test (cm), (5) the agility test (m s-1 ), and (6) the medicine ball throw test (cm). Means and distributional characteristics of the population were assessed using ANOVA, ANCOVA adopting BMI as the body-size covariate, Levene's test of equality-of-error variances, and Box and whisker plots. RESULTS: ANOVAs and ANCOVA's identified significant declines in physical fitness over time/year in 5 of the 6 physical fitness variables (e.g., 20-m sprint speed slope B = -0.018 (m s-1 y-1 ); 95% CI -0.019 to -0.017; p < 0.001), the only exception being the medicine ball throw test (cm). The Levene's test of equality-of-error variances also identified a systematic increase in the variances/standard deviations over time/years. CONCLUSIONS: Results provide powerful evidence that children and adolescents' physical fitness is declining, a trend that is also diverging asymmetrically, becoming more extreme in more recent years. The "fit" appear to be getting fitter, but the fitness of the "less-fit" appears to be declining further. These results have important implications for sports medicine and government policy makers.

Change of Direction Speed in Youth Male Soccer Players: The Predictive Value of Anthropometrics and Biological Maturity.

This study aimed to develop the optimal allometric body size/shape and a biological maturity model that predicted the change of direction (CoD) mean speed performance in youth male soccer players. One-hundred and fifteen youth soccer players (age: 12.4 [1.3] y) participated in this study. The 505 test was used to assess CoD mean speed performance. Anthropometric measurements comprised body height (cm), sitting height (cm), body mass (kg), fat mass (kg), lower limb length (cm), thigh length (cm), leg length (cm), foot length (cm), thigh girth (cm), and calf girth (cm). The maturity status was determined based on the maturity offset method. To identify size/shape and maturity characteristics associated with CoD speed performance, we computed a multiplicative allometric log-linear regression model, which was refined using backward elimination. The multiplicative allometric model exploring the association between 505 CoD mean speed performance and the different anthropometric characteristics in youth soccer players estimated that fat mass (P < .001), sitting height (P = .02), and maturity offset (P = .004) are the key predictors. More specifically, youths who are more mature and have a lower fat mass and a shorter trunk length, are likely to achieve a better CoD mean speed performance. These findings highlight the relevance of considering anthropometric and maturity characteristics in youth soccer players to support talent identification.

Key Anthropometric Variables Associated With Front-Crawl Swimming Performance in Youth Swimmers: An Allometric Approach.

ABSTRACT: Sammoud, S, Negra, Y, Chaabene, H, Bouguezzi, R, Attia, A, Granacher, U, Younes, H, and Nevill, AM. Key anthropometric variables associated with front-crawl swimming performance in youth swimmers: an allometric approach. J Strength Cond Res 37(6): 1259-1263, 2023-This study aimed to establish key anthropometric characteristics (e.g., optimal body height, limb-segment length, and girth/breadth ratios) related to 100-m front-crawl performance in young swimmers. In total, 74 swimmers (boys [ n = 41; age: 18.1 ± 3.5 years]; girls [ n = 33; age: 15.9 ± 3.1 years]) participated in this study. We adopted a multiplicative allometric log-linear regression model to identify key anthropometric characteristics associated with 100-m front-crawl swimming performance. The main outcomes indicated that length ratio = ([height/leg length]), foot length and ankle girth, biacromial breadth, and % of body fat were associated with 100-m front-crawl mean swimming speed performance. These findings highlight the importance of assessing anthropometric characteristics in young front-crawl swimmers for talent identification and development.

Race Analysis and Determination of Stroke Frequency - Stroke Length Combinations during the 50-M Freestyle Event.

The aims of this study were to: (1) analyze and compare the stroke kinematics between junior and senior elite male swimmers in every section of the race during the 50-m freestyle event, and; (2) identify stroke frequency (SF)-stroke length (SL) combinations on swim speed independently for junior and senior swimmers in each section of the 50-m freestyle event. Eighty-six junior swimmers (2019) and 95 seniors (2021) competing in the 50-m long course meter LEN Championships were analyzed. The t-test independent samples (p ≤ 0.05) were used to compare juniors and seniors. The SF and SL combinations on swim speed were explored using three-way ANOVAs. Senior swimmers were significantly faster in the 50-m race than juniors (p < 0.001). Speed presented the largest significant difference (p < 0.001) in section S0-15 m (start until the 15th meter mark) being seniors fastest. Both junior and senior swimmers revealed a significant categorization (p < 0.001) by stroke length and stroke frequency in each race section. It was possible to model several SF-SL combinations for seniors and juniors in each section. The fastest swim speed in each section, for seniors and juniors independently, was achieved by a SF-SL combination that may not be the fastest SF or the longest SL. Coaches and swimmers must be aware that despite the 50-m event being an all-out bout, several SF-SL combinations were observed (independently for juniors and seniors), and they differ between race sections.

What is the optimal anthropometric index/ratio associated with two key measures of cardio-metabolic risk associated with hypertension and diabetes?

BACKGROUND: Few studies have investigated the optimal anthropometric index associated with potential cardio-metabolic risk. Using direct measures of standing height, body mass, and waist circumference, we sought to identify the optimal index for detecting cardio-metabolic risk associated with diabetes and hypertension in a nationally representative sample of US adults. METHODS: Complete (non-missing) cross-sectional data from 8375 US adults aged 18-80+ years were obtained from the 2015-16 and 2017-March 2020 (pre-pandemic) cycles of the National Health and Nutrition Examination Survey. The cardio-metabolic risk was identified using blood pressure and glycohemoglobin (A1c). Allometric models were used to identify the optimal anthropometric indices associated with cardio-metabolic risk. Receiver operating characteristics curves were used to verify the discriminatory ability of the identified index in comparison with other anthropometric measures. RESULTS: The optimal anthropometric index associated with cardio-metabolic risk was waist circumference divided by body mass to the power of 0.333 (WC/M0.333). The ability for this new index to discriminate those with diabetes (area under the ROC curve: 0.73 [95%CI: 0.71-0.74]) and hypertension (area under the curve: 0.70 [95%CI: 0.69-0.72]) was superior to all other anthropometric measure/indices investigated in this study (body mass index, waist circumference, waist-to-height ratio, and waist/height0.5). CONCLUSIONS: We identified WC/M0.333 as the optimal anthropometric index for identifying US adults with hypertension and diabetes. Instead of using body mass index (kg/m2), we recommend using WC/M0.333 in clinical and public health practice to better identify US adults at potential cardio-metabolic risk associated with hypertension and diabetes.

Adherence to aerobic and muscle-strengthening components of the physical activity guidelines and mental health.

Despite a clear distinction between aerobic and muscle strengthening (MS) components in the physical activity guidelines, public health surveillance has largely focused only on aerobic components, limiting the reach of epidemiological research on the physical activity guidelines. Hence, this study investigated the association between adherence to both components (i.e. aerobic and muscle-strengthening) of the World Health Organization's physical activity guidelines and mental health among the college student population. A cross-sectional study was conducted among a nationally representative sample of Irish college students (7088 participants, M age: 23.17 years; 50.9% female). Participants were categorized as meeting both components of the guidelines (n = 41%), only the aerobic component (n = 25.3%) or the MS component (n = 7.3%), and neither (n = 26.4%). Group membership effects on mental health was determined through mixed univariate ANOVAs, with a Bonferroni correction for post hoc analyses to assess multiple comparisons. Results revealed that meeting both components of the guidelines was significantly (all p < 0.01) associated with greater self-reported happiness, body image and general health, and less mental ill-being, relative to all other respective groupings. Meeting aerobic or MS components in isolation was significantly (p < 0.05) associated with better happiness, general health and body image compared to not meeting either component. To conclude, 59% of the college-aged population are insufficiently active, and adherence to both guideline components is positively associated with mental health. Co-produced, evidence-based, physical activity interventions are needed in students and could contribute to mental health promotion.

The Association Between Training Load Indices and Injuries in Elite Soccer Players.

ABSTRACT: Tiernan, C, Comyns, T, Lyons, M, Nevill, AM, and Warrington, G. The association between training load indices and injuries in elite soccer players. J Strength Cond Res 36(11): 3143-3150, 2022-To investigate the association between contact injuries, noncontact injuries, and training load indices, across different lag periods in elite soccer players. Internal load (session rate of perceived exertion) was collected from 15 elite soccer players over 1 season (40-weeks). Acute (7 days), chronic (28 days), acute:chronic workload ratio (ACWR) (uncoupled), exponentially weighted moving averages (EWMA) ACWR, and 2-, 3-, and 4-week cumulative load were calculated on a rolling weekly basis. Multilevel logistic regression was used to analyze the associations between contact, noncontact injuries, and training load indices, across different lag periods (5 and 7 days). A player was at a significantly higher risk of a noncontact injury 5 days later, if week-to-week acute load changes increased (odds ratio [OR] = 1.97). An increase in EWMA ACWR was associated with an increased risk of both a contact (OR = 1.30) and noncontact injury (OR = 1.35), 5 days later. An increase in 2-week cumulative load (OR = 1.77) was associated with an increased risk of a contact injury 7 days later and 3-week cumulative load (OR = 1.55) 5 days later. These findings suggest that to reduce the potential risk of a noncontact injury, training load should be gradually increased, avoiding an increase in week-to-week acute load change (≥9%) or EWMA ACWR (>1.20). Findings indicated that EWMA ACWR may be a more sensitive measure for detecting a player at a higher risk of an injury than ACWR. Furthermore, a high 2- and 3-week cumulative load was associated with an increased risk of a contact injury, which may indicate accumulated fatigue. Practitioners must note that this study investigated associations with injury risk and not injury prediction.

Injury Incidence and Severity in Musical Theatre Dance Students: 5-year Prospective Study.

Dance injury research has mainly focused on ballet and modern dance with little data on musical theatre dancers. The purpose was to assess the incidence and severity of injuries in a musical theatre dance college over a 5-year period; 198 pre-professional musical theatre dancers (3 cohorts on a 3-year training course) volunteered for the study; 21 students left the course over the study period. Injury aetiology data were collected by an in-house physiotherapy team. Differences between academic year and sex were analysed using a Poisson distribution model; significant difference was set at p≤0.05. In total, 913 injuries were recorded, and more injuries occurred in academic year 1 than year 2 and 3. Overall injury incidence was 1.46 injuries per 1000 hours (95% CI 1.34, 1.56); incidence significantly decreased between year 1, 2 and 3 (p<0.05). There was no significant sex difference for incidence or severity. Most injuries were classified as overuse (71% female, 67% male). Pre-professional musical theatre dancers report a high proportion of lower limb and overuse injuries comparable to other dance genres. Unlike other studies on pre-professional dancers, injury incidence and severity decreased with academic year, even though workload increased across the course.

The influence of anthropometric variables, body composition, propulsive force and maturation on 50m freestyle swimming performance in junior swimmers: An allometric approach.

The purpose of the current article was to use allometric models to identify the best body size descriptors and other anthropometric variables, body composition, and offset maturity that might be associated with the youngsters' 50m personal-best (PB) swim speeds (m·s-1). Eighty-five competitive swimmers (male, n=50; 13.5±1.8 y; female, n=35; 12.6±1.8 y) participated in this study. Height, body mass, sitting height, arm span, skinfolds, arm muscle area (AMA), and maturity offset were assessed. Swimming performance was taken as the PB time recorded in competition, and the propulsive force of their arm (PFA) was assessed by the tied swimming test. The multiplicative allometric model relating 50m PB swim speeds (m·s-1) to all the predictor variables found percentage body fat as a negative [(BF%) ß= -.121±.036; P=0.001], and PFA (PFA ß=.108±.033; P=0.001) and the girl's arm span (ß=.850±.301; P=0.006), all log-transformed, as positive significant predictors of log-transformed swim speed. The adjusted coefficient of determination, Radj2 was 54.8% with the log-transformed error ratio being 0.094 or 9.8%, having taken antilogs. The study revealed, using an allometric approach, that body fatness and PFA were significant contributors to 50m freestyle swim performance in young swimmers.

Speed agility trends in children according to growth.

BACKGROUND: Speed agility is considered as the whole assessment of speed of movement, agility and coordination. The 10x4m test has been broadly used to evaluate physical fitness and overall health in children of developmental ages. A myriad of studies have investigated the ecology of speed agility (SA). However, body dimensions are rarely appraised, and this is a weakness because body shapes are affected by growth. AIM: This study aimed to model SA-specific allometric equations, and develop an approach objectively predictive for performance while controlling for maturity through age at peak height velocity (agePHV). SUBJECTS AND METHODS: A total of 7317 (3627 girls) children aged 8-11 years were SA-tested. Multiplicative models with allometric body-size components, agePHV, and categorical differences, were implemented to evaluate SA performance. RESULTS: Model 1 accounted for body-size and shape only, whereas Model 2 included agePHV and Model 3 considered standing broad jump (SBJ) as a surrogate marker for explosive strength. An ectomorphic dominance was revealed across all the models. CONCLUSION: The explosive strength resulted in influencing SA per height-to-weight ratio. Further, positive exponent of agePHV suggested that the late maturers were likely to show better SA performances. Predictive equations modelled on developmental factors are fundamental to scrutinise performances as valuable health and fitness outcomes in childhood.

Key somatic variables associated with, and differences between the 4 swimming strokes.

This study identified key somatic and demographic characteristics that benefit all swimmers and, at the same time, identified further characteristics that benefit only specific swimming strokes. Three hundred sixty-three competitive-level swimmers (male [n = 202]; female [n = 161]) participated in the study. We adopted a multiplicative, allometric regression model to identify the key characteristics associated with 100 m swimming speeds (controlling for age). The model was refined using backward elimination. Characteristics that benefited some but not all strokes were identified by introducing stroke-by-predictor variable interactions. The regression analysis revealed 7 "common" characteristics that benefited all swimmers suggesting that all swimmers benefit from having less body fat, broad shoulders and hips, a greater arm span (but shorter lower arms) and greater forearm girths with smaller relaxed arm girths. The 4 stroke-specific characteristics reveal that backstroke swimmers benefit from longer backs, a finding that can be likened to boats with longer hulls also travel faster through the water. Other stroke-by-predictor variable interactions (taken together) identified that butterfly swimmers are characterized by greater muscularity in the lower legs. These results highlight the importance of considering somatic and demographic characteristics of young swimmers for talent identification purposes (i.e., to ensure that swimmers realize their most appropriate strokes).

The dose-response association between V̇O2peak and self-reported physical activity in children.

BACKGROUND: Previous research into the association between aerobic fitness and physical activity in children is equivocal. However, previous research has always assumed that such an association was linear. This study sought to characterize the dose-response association between physical activity and aerobic fitness and to assess whether this association is linear or curvilinear and varies by sex, age and weight status. METHODS: Physical activity (assess using the Physical Activity Questionnaire), aerobic fitness (20 m shuttle-run), BMI, screen-time and socio-demographic data were collected at ages 12, 14 and 16 years in (n = 1422) volunteers from 9 English schools. Multilevel-regression modelling was used to analyse the longitudinal data. RESULTS: The analysis identified a significant inverted "u-shaped" association between VO2max and PAQ. This relationship remained having controlling for the influences of sex, age and weight status. Daily screen time >4 hours and deprivation were also associated with being less fit (P < 0.01). CONCLUSIONS: This longitudinal study suggests that the dose-response relationship between PA and aerobic fitness in children is curvilinear. The health benefits of PA are greater in less active children and that sedentary and less active children should be encouraged to engage in PA rather than more active children to increase existing levels of PA.

Salivary IgA as a Predictor of Upper Respiratory Tract Infections and Relationship to Training Load in Elite Rugby Union Players.

Tiernan, C, Lyons, M, Comyns, T, Nevill, AM, and Warrington, G. Salivary IgA as a predictor of upper respiratory tract infections and relationship to training load in elite rugby union players. J Strength Cond Res 34(3): 782-790, 2020-Upper Respiratory Tract Infections (URTI) are among the most common illnesses reported in athletes. An URTI can result in missed training days, which in turn may lead to performance decrements. The purpose of this study was to investigate the use of salivary immunoglobulin A (sIgA) as a predictor of URTI, while also exploring the relationship to weekly training load in elite rugby union players. Nineteen male elite rugby union players provided morning saliva swabs, biweekly (Monday and Friday), over a 10-week training period. Participants completed an illness log documenting symptoms of URTI. Session Rate of Perceived Exertion (sRPE) was collected to determine training load (sRPE × session duration). Weekly training load was also calculated. Logistic regression was used to analyze the relationship between incidences of URTI with sIgA and training load. Multilevel regression was conducted to compare associations between sIgA and training load. The results found that the likelihood of suffering from an URTI increased when sIgA significantly decreased (p = 0.046). Where sIgA decreased by 65% or more, a player was at a greater risk of contracting an URTI within the following 2 weeks. No association was found between sIgA and training load. In conclusion, sIgA may be a useful predictor for determining the likelihood of players contracting an URTI. This will allow the coach to make informed decisions on training status, helping reduce the risk of players missing training, which may have performance decrements. Coaches will benefit from the fast, easy, and instant results available, to analyze a player's immune function.

A new waist-to-height ratio predicts abdominal adiposity in adults.

Our aim was to identify the best anthropometric index associated with waist adiposity. The six weight-status indices included body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHTR), and a new waist-by-height0.5 ratio (WHT.5R). The association between three waist skinfolds and the six anthropometric indices was conducted using ANCOVA, MANCOVA, allometric modelling and non-linear regression. The strongest predictors of waist adiposity were (1st) WHT.5R, (2nd) WHTR, (3rd) waist circumference (WC), (4th) BMI, (5th) WHR, and lastly (6th) a body shape index ABSI = WC/(BMI2/3 * height1/2). The allometric and non-linear regression analyses identified the optimal waist-to-height ratio associated with waist adiposity to be (waist * height -0.6). The 95% confidence intervals of the height exponents encompassed -0.5 but excluded -1.0 assumed by WHTR. Assuming that excess waist adiposity is an important cardiovascular risk factor, we recommend that the new WHT.5R be used to advise people how to maintain a "healthy" weight.

The Relationship Between Adductor Squeeze Strength, Subjective Markers of Recovery and Training Load in Elite Rugby Players.

Tiernan, C, Lyons, M, Comyns, T, Nevill, AM, and Warrington, G. The relationship between adductor squeeze strength, subjective markers of recovery and training load in elite Rugby players. J Strength Cond Res 33(11): 2926-2931, 2019-The adductor squeeze strength test has become a popular training monitoring marker, particularly in team sports. The aim of this study was to investigate the relationship between adductor squeeze strength scores, subjective markers of recovery and training load in elite Rugby Union players, because of limited research in this area. Nineteen elite male Rugby Union players completed daily monitoring markers (adductor squeeze strength and 5 selected subjective markers of recovery), over a 10-week preseason training period. Rate of perceived exertion (RPE) was collected to determine training load (session RPE; RPE × session duration) and to calculate weekly training load. Spearman's correlation was used to analyze the relationship between adductor squeeze strength scores, subjective markers of recovery, and weekly training load. The results found that where adductor squeeze scores decreased, both perceived fatigue levels (r = -0.335; R = 11.2%; p < 0.001) and muscle soreness (r = -0.277; R = 7.7%; p < 0.001) increased. A weak correlation was found between Monday adductor squeeze strength scores and the previous week's training load (r = -0.235; R = 5.5%; p < 0.001) and Friday adductor squeeze strength scores and the same week's training load (r = -0.211; R = 4.5%; p < 0.05). These results show that adductor squeeze strength may provide coaches with a time-efficient, low-cost objective, player monitoring marker. Additionally, the combination of adductor strength squeeze, with subjective markers, perceived fatigue, and muscle soreness, and appropriately planned training load may help coaches to optimize training adaptations by determining a player's training status.

Physical activity for women with breast cancer after adjuvant therapy.

BACKGROUND: Women with a diagnosis of breast cancer may experience short- and long-term disease and treatment-related adverse physiological and psychosocial outcomes. These outcomes can negatively impact prognosis, health-related quality of life (HRQoL), and psychosocial and physical function. Physical activity may help to improve prognosis and may alleviate the adverse effects of adjuvant therapy. OBJECTIVES: To assess effects of physical activity interventions after adjuvant therapy for women with breast cancer. SEARCH METHODS: We searched the Cochrane Breast Cancer Group (CBCG) Specialised Registry, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Physiotherapy Evidence Database (PEDro), SPORTDiscus, PsycINFO, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform, on 18 September 2015. We also searched OpenGrey and Healthcare Management Information Consortium databases. SELECTION CRITERIA: We searched for randomised and quasi-randomised trials comparing physical activity interventions versus control (e.g. usual or standard care, no physical activity, no exercise, attention control, placebo) after adjuvant therapy (i.e. after completion of chemotherapy and/or radiation therapy, but not hormone therapy) in women with breast cancer. DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies, assessed risk of bias, and extracted data. We contacted trial authors to ask for additional information when needed. We calculated an overall effect size with 95% confidence intervals (CIs) for each outcome and used GRADE to assess the quality of evidence for the most important outcomes. MAIN RESULTS: We included 63 trials that randomised 5761 women to a physical activity intervention (n = 3239) or to a control (n = 2524). The duration of interventions ranged from 4 to 24 months, with most lasting 8 or 12 weeks (37 studies). Twenty-eight studies included aerobic exercise only, 21 involved aerobic exercise and resistance training, and seven used resistance training only. Thirty studies described the comparison group as usual or standard care, no intervention, or control. One-fifth of studies reported at least 20% intervention attrition and the average physical activity adherence was approximately 77%.No data were available on effects of physical activity on breast cancer-related and all-cause mortality, or on breast cancer recurrence. Analysis of immediately postintervention follow-up values and change from baseline to end of intervention scores revealed that physical activity interventions resulted in significant small-to-moderate improvements in HRQoL (standardised mean difference (SMD) 0.39, 95% CI 0.21 to 0.57, 22 studies, 1996 women; SMD 0.78, 95% CI 0.39 to 1.17, 14 studies, 1459 women, respectively; low-quality evidence), emotional function (SMD 0.21, 95% CI 0.10 to 0.32, 26 studies, 2102 women, moderate-quality evidence; SMD 0.31, 95% CI 0.09 to 0.53, 15 studies, 1579 women, respectively; low-quality evidence), perceived physical function (SMD 0.33, 95% CI 0.18 to 0.49, 25 studies, 2129 women; SMD 0.60, 95% CI 0.23 to 0.97, 13 studies, 1433 women, respectively; moderate-quality evidence), anxiety (SMD -0.57, 95% CI -0.95 to -0.19, 7 studies, 326 women; SMD -0.37, 95% CI -0.63 to -0.12, 4 studies, 235 women, respectively; low-quality evidence), and cardiorespiratory fitness (SMD 0.44, 95% CI 0.30 to 0.58, 23 studies, 1265 women, moderate-quality evidence; SMD 0.83, 95% CI 0.40 to 1.27, 9 studies, 863 women, respectively; very low-quality evidence).Investigators reported few minor adverse events.Small improvements in physical activity interventions were sustained for three months or longer postintervention in fatigue (SMD -0.43, 95% CI -0.60 to -0.26; SMD -0.47, 95% CI -0.84 to -0.11, respectively), cardiorespiratory fitness (SMD 0.36, 95% CI 0.03 to 0.69; SMD 0.42, 95% CI 0.05 to 0.79, respectively), and self-reported physical activity (SMD 0.44, 95% CI 0.17 to 0.72; SMD 0.51, 95% CI 0.08 to 0.93, respectively) for both follow-up values and change from baseline scores.However, evidence of heterogeneity across trials was due to variation in intervention components (i.e. mode, frequency, intensity, duration of intervention and sessions) and measures used to assess outcomes. All trials reviewed were at high risk of performance bias, and most were also at high risk of detection, attrition, and selection bias. In light of the aforementioned issues, we determined that the evidence was of very low, low, or moderate quality. AUTHORS' CONCLUSIONS: No conclusions regarding breast cancer-related and all-cause mortality or breast cancer recurrence were possible. However, physical activity interventions may have small-to-moderate beneficial effects on HRQoL, and on emotional or perceived physical and social function, anxiety, cardiorespiratory fitness, and self-reported and objectively measured physical activity. The positive results reported in the current review must be interpreted cautiously owing to very low-to-moderate quality of evidence, heterogeneity of interventions and outcome measures, imprecision of some estimates, and risk of bias in many trials. Future studies with low risk of bias are required to determine the optimal combination of physical activity modes, frequencies, intensities, and durations needed to improve specific outcomes among women who have undergone adjuvant therapy.

Socio-demographic differences in Colombian children's muscular fitness: Does scaling for differences in body size present a challenge to conventional thinking?

OBJECTIVES: In low- to middle-income countries, children from less-deprived areas (from families of higher socio-economic status [SES]) have superior muscular fitness than those from low-SES groups. They are also taller and heavier, factors associated with muscular fitness. The purpose of this study was to identify any socio-demographic differences in Colombian children's muscular fitness and examine how these conclusions can be modified by scaling for differences in body size. METHODS: A total of 38,098 youths (46% girls), ninth grade students (aged 14-15 years), participated in a study of cross-sectional design. We recorded SES and family incomes, stature, and mass. Standing broad jump and handgrip strength were used to assess muscular fitness. A multiplicative allometric model was adopted to adjust for body-size differences. RESULTS: Children from the mid- to high-SES groups jumped significantly higher than children from the lowest SES group, although no SES group difference in grip strength was observed. After adjusting for body size, children from higher SES and with higher family incomes had significantly lower handgrip strength, and their superior jump height performances remained but were greatly reduced. Only children from the highest SES now jumped significantly higher that the lowest SES group. CONCLUSIONS: The superior jump performance and no difference in handgrip strength of Colombian children from higher SES may simply reflect their superior physiques. When body size is accounted for, these differences are reduced or even reversed, suggesting that children from higher SES groups should not be complacent regarding their apparent superior muscular fitness.

Effects of situational variables on the physical activity profiles of elite soccer players in different score line states.

The aim of this study were to investigate the effects of playing position, pitch location, team ability and opposition ability on the physical activity profiles of English premier league soccer players in difference score line states. A validated automatic tracking system (Venatrack Ltd.) was used to track players in real time (at 25 Hz) for total distance covered, high speed running distance and sprint distance. This is the first study to include every team from an entire season in the English premier league, resulting in 376 games, 570 players and 35 000 rows of data from the 2011-12 season being analyzed using multi-level modelling. Multi-level regression revealed an inverted "u" shaped association between total distance covered and goal difference (GD), with greater distances covered when GD was zero and reduced distances when GD was either positive or negative. A similar "u" shaped association was found with high speed distance covered at home. In addition distance covered (both at home and away) were predicted by playing position. All activity profiles (with the exception of sprint distance at home) were predicted by pitch location and time scored. Lastly, distance away from home and high speed running at home were predicted by opposition ability. Score line appears to effect player activity profiles across a number of situational factors and thus should be considered by managers when preparing and selecting teams to maximize performance. The current study also highlighted the need for more sensitive score line definitions in which to consider score line effects.

Cardiorespiratory fitness and activity explains the obesity-deprivation relationship in children.

This study examined the association between obesity and deprivation in English children and whether cardiorespiratory fitness or physical activity (PA) can explain this association. Obesity was assessed using IOTF criteria in 8,398 10-16 year olds. Social deprivation was measured using the Index of Multiple Deprivation (IMD) (subdivided into 3 groups; high, mid and low deprivation). Obesity was analysed using binary logistic regression with stature, age and sex incorporated as confounding variables. Children's fitness levels were assessed using predicted VO2 max (20-metre shuttle run test) and PA was estimated using the PA Questionnaire for Adolescents or Children (PAQ). A strong association was found between obesity and deprivation. When fitness and PA were added to the logistic regression models, increasing levels in both were found to reduce the odds of obesity, although it was only by including fitness into the model that the association between obesity and deprivation disappeared. Including estimated PA into the model was found to be curvilinear. Initial increases in PA increase the odds of obesity. Only by increasing PA to exceed the 71st percentile (PAQ = 3.22) did the odds of being obese start to decline. In order to reduce deprivation inequalities in children's weight-status, health practitioners should focus on increasing cardiorespiratory fitness via physical activity levels in areas of greater deprivation.

The effects of a home-based physical activity intervention on cardiorespiratory fitness in breast cancer survivors; a randomised controlled trial.

The aim of this current randomised controlled trial was to evaluate the effects of a home-based physical activity (PA) intervention on cardiorespiratory fitness in breast cancer survivors. Thirty-two post-adjuvant therapy breast cancer survivors (age = 52 ± 10 years; BMI = 27.2 ± 4.4 kg∙m2) were randomised to a six-month home-based PA intervention with face-to-face and telephone PA counselling or usual care. Cardiorespiratory fitness and self-reported PA were assessed at baseline and at six-months. Participants had a mean relative V̇O2max of 25.3 ± 4.7 ml∙kg-1∙min-1, which is categorised as "poor" according to age and gender matched normative values. Magnitude-based inference analyses revealed likely at least small beneficial effects (effect sizes ≥.20) on absolute and relative V̇O2 max (d = .44 and .40, respectively), and total and moderate PA (d = .73 and .59, respectively) in the intervention compared to the usual care group. We found no likely beneficial improvements in any other outcome. Our home-based PA intervention led to likely beneficial, albeit modest, increases in cardiorespiratory fitness and self-reported PA in breast cancer survivors. This intervention has the potential for widespread implementation and adoption, which could considerably impact on post-treatment recovery in this population.