'At risk' waist-to-height ratio cut-off points recently adopted by NICE and US Department of Defense will unfairly penalize shorter adults. What is the solution?

OBJECTIVES: To a) demonstrate that adopting 'at risk' waist-to-height ratio (WHTR) cut-off points, recently approved by National Institute for Health and Care Excellence (NICE) and the United States Department of Defense (USDoD), will unfairly penalize shorter individuals and will be too lenient for taller individuals, b) to confirm that waist circumference (WC) of a sample of US service personnel, scales to approximately height0.5, supporting the notion that WC, to be independent of height (HT), should be normalized using WC.HT-0.5 (WHT•5R), and c) to identify the WHT•5R cut-off points that will reduce or eliminate this unwanted bias. SUBJECTS/METHODS: We employed a three independent cross-sectional sample design. All n = 58,742 participants underwent anthropometric assessment of body mass, stature and waist circumference. RESULTS: The allometric power-law model WC=a.HT^b for US service personnel identified the height exponent to be b= 0.418 (95 % CI 0.251-0.585), confirming that the simple body-shape index for WC to be independent of HT, should be WC.HT-0.5. Chi-square tests of independence and for linear trend confirmed that by adopting WHTR cut-off point, shorter individuals (both service personnel and non-service participants) will be over penalized (classified as being 'at risk'). New WC independent-of-height ratio cut-off points were found to resolve this problem. CONCLUSIONS: Adopting WHTR cut-off thresholds (either 0.5 or 0.55) will lead to shorter adults being unfairly classified as being 'at risk' in terms of their central adiposity and general health status. Adopting new WHT•5R cut-off point thresholds were found to greatly reduce or eliminate this bias.

Who is meeting the strengthening physical activity guidelines by definition: A cross-sectional study of 253 423 English adults?

The current UK physical activity guidelines recommend that adults aged 19 to 65 years perform activity to strengthen muscle and bone a minimum of twice weekly. The number of adults meeting strengthening activity guidelines is lower than for aerobic activity, but estimates vary between studies partly due to differences in how muscle-strengthening activity is defined. We aimed to provide estimates for strengthening activity prevalence in English adults based on a nationally representative sample of n = 253,423 18-65-year-olds. We attempted to quantify the variation in estimates attributable to differences in the way strengthening activity is defined. Finally, we aim to provide a brief descriptive epidemiology of the factors associated with strengthening activity. Adults met guidelines for aerobic activity if they reported the activity equivalent to >150 min/week moderate-intensity exercise. Respondents met strengthening guidelines if they reported at least two bouts per week of strengthening activity. We defined strengthening activity, first, according to criteria used in the Health Survey for England (HSE). Second, we counted bouts of strengthening activities for which we could find evidence of health-related benefits (Evidence). Third, we included bouts of strengthening activity as defined in current UK physical activity guidelines (Guideline). Two-thirds (67%) of adults met guidelines for aerobic activity (69% of men, 65% of women). Less than one-third (29% of men and 24% of women) met guidelines for the HSE definition of strengthening activity. Under the Evidence definition, 16% of men and 9% of women met strengthening guidelines. Using the most-stringent definition (Guideline) just 7.3% of men and 4.1% of women achieved the recommendations for strengthening activity. We found females and older adults (50-65 years) were less likely to meet guidelines for aerobic, strengthening, and combined aerobic plus strengthening activity. The prevalence of meeting activity guidelines was lower in adults from more deprived areas (compared with the least deprived); Adults with lower academic qualifications (Level 1) were less likely to meet activity guidelines than those educated to Level 4 (Degree Level) or higher. Having a limiting disability was associated with a lower prevalence of meeting activity guidelines. Associations between socio-demographic measures and the prevalence of adults meeting activity guidelines were stronger for strengthening activity than for aerobic 51(or combined aerobic plus strengthening) activity Compared with aerobic activity, fewer adults engage in strengthening activity regardless of how it is defined. The range in estimates for how many adults meet strengthening activity guidelines can be explained by variations in the definition of 'strengthening' that are used and the specific sports or activities identified as strengthening exercise. When strengthening activity is included, the proportion of English adults meeting current physical activity guidelines could be as high as 1 in 3 but possibly as low as just 1 in 20. A harmonized definition of strengthening activity, that is aligned with physical activity guidelines, is required to provide realistic and comparable prevalence estimates.

Obese individuals do not underreport dietary intake to a greater extent than nonobese individuals when data are allometrically-scaled.

OBJECTIVE: The aim of this study was to assess the extent of misreporting in obese and nonobese adults on an absolute, ratio-scaled, and allometrically-scaled basis. METHOD: Self-reported daily energy intake (EI) was compared with total energy expenditure (TEE) in 221 adults (106 male, 115 female; age 53 ± 17 years, stature 1.68 ± 0.09 m, mass 79.8 ± 17.2 kg) who participated in a doubly-labeled water (DLW) subsection of 2013-2015 National Diet and Nutrition Survey. Data were log transformed and expressed as absolute values, according to simple ratio-standards (per kg body mass) and adjusted for body mass allometrically. Absolute and ratio-scaled misreporting were examined using full-factorial General Linear Models with repeated measures of the natural logarithms of TEE or EI as the within-subjects factor. The natural logarithm of body mass was included as a covariate in the allometric method. The categorical variables of gender, age, obesity, and physical activity level (PAL) were the between-factor variables. RESULTS: On an absolute-basis, self-reported EI (2759 ± 590 kcal·d-1 ) was significantly lower than TEE measured by DLW (2759 ± 590 kcal·d-1 : F1,205  = 598.81, p < .001, ηp 2 =0.75). We identified significantly greater underreporting in individuals with an obese BMI (F1,205  = 29.01, p <.001, ηp 2 =0.12), in more active individuals (PAL > 1.75; F1,205  = 34.15, p <.001, ηp 2 =0.14) and in younger individuals (≤55 years; F1,205  = 14.82, p < .001, ηp 2 =0.07), which are all categories with higher energy needs. Ratio-scaling data reduced the effect sizes. Allometric-scaling removed the effect of body mass (F1,205 =0.02, p = 0.887, ηp 2 =0.00). CONCLUSION: In weight-stable adults, obese individuals do not underreport dietary intake to a greater extent than nonobese individuals. These results contradict previous research demonstrating that obesity is associated with a greater degree of underreporting.

Associations between cardiorespiratory fitness, fatness, hemodynamic characteristics, and sedentary behaviour in primary school-aged children.

BACKGROUND: Low cardiorespiratory fitness (CRF) is associated with the development of cardiovascular diseases during childhood, adolescence and older ages. The purpose of the study was to investigate associations between fatness, hemodynamic characteristics and secondary time with CRF in primary school-aged children. METHODS: Height, weight, body mass index (BMI), blood pressure (BP), heart rate (HR), CRF (20 m shuttle-run) and sedentary time were measured for 105 children (categorized as normal, overweight, obese). The independent sample t-test checked for differences and one-way ANOVA-Post Hoc Test and stepwise linear regression analysis assessed the 20 m shuttle-run performance predictors. RESULTS: There was a statistically significant difference in CRF between boys and girls. There was a statistically significant difference between (p < 0.05) CRF for Normal weight (M = 47.58 ± 3.26 kg m-2) and Obese (M = 44.78 ± 3.23 kg m-2). CRF correlated with age, BMI and sedentary time (r > 0.3; p < 0.05). BMI is the best independent predictor of CRF. CONCLUSIONS: Children with normal BMI tend to present better CRF performance than obese and overweight children. Sedentary behaviour is associated with lower CRF in primary school-aged children.

The associations between physical activity intensity, cardiorespiratory fitness, and non-alcoholic fatty liver disease.

BACKGROUND AND AIM: High levels of physical activity and cardiorespiratory fitness may protect against non-alcoholic fatty liver disease. We investigated whether different physical activity intensities and cardiorespiratory fitness were independent predictors of non-alcoholic fatty liver disease. METHODS: We included healthy adults with no prior diagnosis of liver dysfunction. Non-alcoholic fatty liver disease prevalence was estimated based on fatty liver index scores. We created tertiles of self-reported low, moderate, and vigorous physical activity. Participants completed an incremental treadmill test to estimate cardiorespiratory fitness, and data were subsequently separated into quintile groups (Q1 [least fit] through Q5 [most fit]). RESULTS: Non-alcoholic fatty liver disease prevalence in our sample of 7111 adults was 28.3% in male adults and 6.5% in female adults. Logistic regression showed the relative odds of non-alcoholic fatty liver disease were 42% lower if > 60 min/week of vigorous physical activity was maintained (odds ratio [OR] = 0.58, confidence interval [CI]: 0.49-0.68). There was a negative dose-response association between cardiorespiratory fitness and non-alcoholic fatty liver disease between Q1 and Q4. Compared with Q1, odds were 39% (OR = 0.61, CI: 0.51-0.73) lower in Q2, through to 51% lower in Q5 (OR = 0.49, CI: 0.41-0.60). Moderate physical activity did not reduce the odds of non-alcoholic liver disease. CONCLUSIONS: We found the lowest prevalence of non-alcoholic fatty liver disease in adults achieving > 60 min/week of vigorous physical activity. However, a stronger dose-response relationship existed between cardiorespiratory fitness and non-alcoholic fatty liver disease. Improving cardiorespiratory fitness as a potential therapeutic target for treatment and prevention of non-alcoholic fatty liver disease warrants further investigation.

Effects of activity pacing in patients with chronic conditions associated with fatigue complaints: a meta-analysis.

A meta-analysis was conducted to (1) determine the effect of activity pacing interventions on fatigue, physical functioning and physical activity among patients with chronic conditions associated with fatigue complaints, and to (2) examine potential moderator effects of trial characteristics (components of intervention and amount of patient-provider contact). Six studies were included in the meta-analysis. Relevant content of the studies was extracted and rated on methodological quality. Random-effects modeling was used to pool data across studies. Medium (standardized mean difference =0.50) and marginal (standardized mean difference =0.34) effects were found for fatigue at post-treatment and follow-up respectively. Inconsequential effects were found for physical functioning and activity (standardized mean difference =0.08-0.30) at both assessment points. Subgroup analyses revealed components of intervention and amount of patient-provider contact were not the source of variance. Minimal patient-provider contact had an effect on fatigue comparable in magnitude to more intensive contact. This meta-analysis of activity pacing in patients with fatigue complaints suggests that activity pacing might have sustained beneficial effects on fatigue management, in particular on fatigue reduction. The divergence in effects for all outcomes suggests that alternative ways such as tailoring advice to individual's behavior toward physical activity may be more successful.Implications for rehabilitationIn a relatively small sample this meta-analysis shows fatigue severity improved after activity pacing interventions and provides a basis to integrate activity pacing in activity stimulation programs for persons with chronic conditions.Activity pacing can feasibly be implemented within standard health care to manage fatigue and physical activity behaviors in persons with chronic conditions.

Cross-cultural comparisons of aerobic and muscular fitness in Tanzanian and English youth: An allometric approach.

Comparisons of physical fitness measures between children or within group measures over time are potentially confounded by differences in body size. We compared measures of strength (handgrip) and aerobic fitness (running-speed [20m shuttle-run]) of 10.0-15.9 year-olds from Dar es Salaam, Tanzania (n = 977) with schoolchildren from England (n = 1014) matched for age and sex. Differences in fitness were analyzed using general linear models, with allometric scaling for body size (mass and stature) and further adjustments for physical activity. Mean handgrip of Tanzanians was lower than English youth (F = 165.0, P<0.001, ηp2 = .079). The difference became trivial when run-speed was scaled for body size (ηp2 = .008). Running-speed of the English children was higher than in Tanzanians (F = 16.0, P<0.001, ηp2 = .014). Allometric scaling for accentuated this between-county difference in running-speed (ηp2 = .019) but when adjusted for physical activity between-country differences in running-speed were trivial (ηp2 = .008). These data contradict those studies showing poor muscular fitness in African youth and highlight the need for appropriate scaling techniques to avoid confounding by differences in body size. In contrast to those from rural areas, our sample of contemporary urban Tanzanians were less aerobically fit than European youth. Differences were independent of body size. Lower aerobic fitness of urban Tanzanian youth may be due to reported physical activity levels lower than those of English youth and lower still than previously reported in rural Tanzania.

The concept of margins of stability can be used to better understand a change in obstacle crossing strategy with an increase in age.

The purpose of the current study was to use the margins of stability (MoS) to investigate how older adults choose between minimizing the risk of a forward fall when crossing an obstacle and the ease of maintaining forward progression during the steps taken behind the obstacle. In the current study 143 community-dwelling older adults aged between 55 and 83 years old, were divided into three age groups based on tertials of age. All participants were asked to complete five trials of obstacle walking and five trials of normal walking. For the trials of normal walking, the main difference between groups was that MoS at initial contact was lower in the older age groups. For the trials of obstacle crossing the MoS at the instants of obstacle crossing with both the leading and trailing limb became smaller with an increase in age. This result might imply that older people choose to use a strategy during obstacle crossing that results in smaller chance of falling forward if an obstacle was struck. A negative consequence of this more conservative strategy was a smaller MoS at the instants of initial contact after crossing the obstacle, thus a larger chance of a backward fall. These findings provide more insight into the regulation of stability during obstacle crossing and specifically in the differences in strategy between younger and older people, and therefore these results might be used for further research to investigate whether obstacle crossing strategies are trainable in older adults, which could be used as advisory programs aimed at fall prevention and/or engagement in an active lifestyle.

Temporal trends in muscular fitness of English 10-year-olds 1998-2014: An allometric approach.

OBJECTIVES: To identify temporal trends in muscular fitness of English children using allometric scaling for height and weight to adjust for the influence of body size. DESIGN: Repeated cross-sectional study. METHODS: We measured; height, weight, standing broad-jump, handgrip, sit-ups and bent-arm hang in 10-year-old boys and girls from Chelmsford, England in: 2014 (n=306), 2008 (n=304) and 1998 (n=310). Physical activity was (PAQ-C) was assessed in 2008 and 2014. Muscular fitness was allometrically scaled for height and weight. We assessed temporal trends using General Linear Models (fixed factors: wave and sex) and reported effect sizes using partial eta squared (ηP2). We compared percentage change per year 1998-2008 with 2008-2014. RESULTS: Ten-year-olds in 2014 were taller and heavier than in 2008 and 1998 but there were no differences in BMI. Compared with 2008, physical activity was lower in boys (ηP2=0.012) and girls (ηP2=0.27) assessed in 2014. There were significant main effects of wave for handgrip (ηP2=0.060), sit-ups (ηP2=0.120) and bent-arm hang (ηP2=0.204). Pairwise comparisons showed muscular fitness of both sexes was significantly lower in 2014 than in 1998. From 2008 to 2014 percent change per year in handgrip (1.6%) and sit-ups (3.9%) were greater than for the preceding decade (handgrip 0.6%, sit-ups 2.6%). CONCLUSIONS: Downward temporal trends in muscular fitness appear independent of secular changes in body size. We found a decrease in self-reported physical activity concurrent with the accelerated declines in fitness from 2008 to 2014. These findings suggest the declines in children are not engaging in physical activities which support development of muscular fitness.

Maturation-Related Differences in Adaptations to Resistance Training in Young Male Swimmers.

Moran, J, Sandercock, GRH, Ramírez-Campillo, R, Wooller, J-J, Logothetis, S, Schoenmakers, PPJM, and Parry, DA. Maturation-related differences in adaptations to resistance training in young male swimmers. J Strength Cond Res 32(1): 139-149, 2018-This study examined the effects of resistance training on muscular strength and jump performances in young male swimmers. It was hypothesized that adaptations would be of a lower magnitude in less mature (prepeak height velocity [PHV]) than in more mature (post-PHV) subjects. Fourteen pre-PHV (-1.8 ± 1.0 years) and 8 post-PHV (1.6 ± 0.5 years) swimmers undertook a 30 minutes, twice-weekly resistance training program for 8 weeks. They were compared with matched control groups (pre-PHV: -2.0 ± 1.1, n = 15; post-PHV: 1.2 ± 1.0, n = 7). The effects on lower-body isometric strength (LBS), measured with midthigh pull, and vertical jump (VJ) height in the post-PHV group were large (effect size: 1.3 [0.4 to 2.2]) and small (0.4 [-0.4 to 1.2]), respectively. Effects on LBS and VJ height in the pre-PHV group were moderate (0.8 [0.1 to 1.4]) and trivial (0.2 [-0.5 to 0.8]), respectively. Estimates in the post-PHV control group (LBS: 0.7 [-0.2 to 1.6]; VJ: 0.2 [-0.7 to 1.0]) and the pre-PHV control group (LBS: 0.1 [-0.5 to 0.7]; VJ: -0.3 [-0.9 to 0.3]) may indicate the extent to which maturation could contribute to the performance changes seen in the respective training groups. Lower-body isometric strength and VJ are trainable, but to different magnitudes, in pre- and post-PHV swimmers. After appropriate foundational training to establish technical competency, twice-weekly resistance training sessions of 30 minutes duration, comprising 3 sets of 4 exercises can be effective in pre- and post-PHV youth.

Maturation-related adaptations in running speed in response to sprint training in youth soccer players.

OBJECTIVES: This study investigated the effects of a previously recommended dose of sprint training (ST) in young male soccer players of differing maturity status. DESIGN: Quasi-experimental design. METHODS: Male soccer players from two professional academies were divided into Pre-PHV (Training: n=12; Control: n=13) and Mid-PHV (Training: n=7; Control=10) groups. The training groups completed 16 sprints of 20m with 90s recovery, once per week for 8weeks. RESULTS: Between-group effect sizes (ES) were substantially larger in Pre-PHV (10m [1.54, CI: 0.74-2.23]; 20m [1.49, CI: 0.75-2.23]; 5-10-5 [0.92, CI: 0.23-1.61]) than in Mid-PHV (10m [-0.00, CI: -0.81 to 0.81]; 20m [-0.12, CI: -0.93 to 0.69]; 5-10-5 [-0.41, CI: -1.22 to 0.41]). Within-group effects demonstrated a similar, though less accentuated, trend which revealed ST to be effective in both Pre-PHV (10m [0.44, CI: -0.24 to 1.12]; 20m [0.45, CI: -0.23 to 1.13]; 5-10-5 [0.69, CI: 0.00-1.38]) and Mid-PHV (10m [0.51, CI: -0.38 to 1.40]; 20m [0.33, CI: -0.56 to 1.21]; 5-10-5 [0.43, CI: -0.46 to 1.32]). CONCLUSIONS: ST, in the amount of 16 sprints over 20m with a 90s rest, may be more effective in Pre-PHV youths than in Mid-PHV youths.

The Relationship between Socioeconomic Status, Family Income, and Measures of Muscular and Cardiorespiratory Fitness in Colombian Schoolchildren.

OBJECTIVE: To determine the associations between socioeconomic status (SES) and physical fitness in a sample of Colombian youth. STUDY DESIGN: Prueba SER is cross-sectional survey of schoolchildren in Bogota, Colombia. Mass, stature, muscular fitness (standing long-jump, handgrip), and cardiorespiratory fitness (20-m shuttle run) were measured in 52?187 schoolchildren 14-16 years of age. Area-level SES was categorized from 1 (very low) to 4 (high) and parent-reported family income was categorized as low, middle, or high. RESULTS: Converting measures into z scores showed stature, muscular, and cardiorespiratory fitness were significantly (z?=?0.3-0.7) below European values. Children in the mid- and high SES groups jumped significantly further than groups with very low SES. Differences were independent of sex but became nonsignificant when adjusted for anthropometric differences. Participants in the mid-SES and high-SES groups had better handgrip scores when adjusted for body dimension. There were, however, no significant between-group differences in cardiorespiratory fitness, which was strongly clustered by school and significantly greater in students from private schools. CONCLUSIONS: Area-level SES is associated with measures of muscular fitness in Colombian schoolchildren. These associations were largely explained by the large differences in body dimensions observed between SES groups. When area-level SES is considered, there was no evidence that family income influenced fitness. The clustering of outcomes reaffirms the potential importance of schools and area-level factors in promoting fitness through opportunities for physical activity. Interventions implemented in schools, can improve academic attainment; a factor likely to be important in promoting the social mobility of children from poorer families.

Age-Related Variation in Male Youth Athletes' Countermovement Jump After Plyometric Training: A Meta-Analysis of Controlled Trials.

Moran, J, Sandercock, GRH, Ramírez-Campillo, R, Meylan, CMP, Collison, J, and Parry, DA. Age-related variation in male youth athletes' countermovement jump after plyometric training: A meta-analysis of controlled trials. J Strength Cond Res 31(2): 552-565, 2017-Recent debate on the trainability of youths has focused on the existence of periods of accelerated adaptation to training. Accordingly, the purpose of this meta-analysis was to identify the age- and maturation-related pattern of adaptive responses to plyometric training in youth athletes. Thirty effect sizes were calculated from the data of 21 sources with studies qualifying based on the following criteria: (a) healthy male athletes who were engaged in organized sport; (b) groups of participants with a mean age between 10 and 18 years; and (c) plyometric-training intervention duration between 4 and 16 weeks. Standardized mean differences showed plyometric training to be moderately effective in increasing countermovement jump (CMJ) height (Effect size = 0.73 95% confidence interval: 0.47-0.99) across PRE-, MID-, and POST-peak height velocity groups. Adaptive responses were of greater magnitude between the mean ages of 10 and 12.99 years (PRE) (ES = 0.91 95% confidence interval: 0.47-1.36) and 16 and 18 years (POST) (ES = 1.02 [0.52-1.53]). The magnitude of adaptation to plyometric training between the mean ages of 13 and 15.99 years (MID) was lower (ES = 0.47 [0.16-0.77]), despite greater training exposure. Power performance as measured by CMJ may be mediated by biological maturation. Coaches could manipulate training volume and modality during periods of lowered response to maximize performance.

Reference values for the incremental shuttle walk test in patients with cardiovascular disease entering exercise-based cardiac rehabilitation.

The incremental shuttle walk test (ISWT) is used to assess functional capacity of patients entering cardiac rehabilitation. Factors such as age and sex account for a proportion of the variance in test performance in healthy individuals but there are no reference values for patients with cardiovascular disease. The aim of this study was to produce reference values for the ISWT. Participants were n = 548 patients referred to outpatient cardiac rehabilitation who underwent a clinical examination and performed the ISWT. We used regression to identify predictors of performance and produced centile values using the generalised additive model for location, scale and shape model. Men walked significantly further than women (395 ± 165 vs. 269 ± 118 m; t = 9.5, P < 0.001) so data were analysed separately by sex. Age (years) was the strongest predictor of performance in men (ß = -5.9; 95% CI: -7.1 to -4.6 m) and women (ß = -4.8; 95% CI: -6.3 to 3.3). Centile curves demonstrated a broadly linear decrease in expected ISWT values in males (25-85 years) and a more curvilinear trend in females. Patients entering cardiac rehabilitation present with highly heterogeneous ISWT values. Much of the variance in performance can be explained by patients' age and sex. Comparing absolute values with age-and sex-specific reference values may aid interpretation of ISWT performance during initial patient assessment at entry to cardiac rehabilitation.

A meta-analysis of maturation-related variation in adolescent boy athletes' adaptations to short-term resistance training.

This meta-analysis investigated the maturation-related pattern of adaptations to resistance training in boy athletes. We included studies examining the effects of 4-16-week resistance training programmes in healthy boy athletes aged 10-18 years. Pooled estimates of effect size for change in strength across all studies (n = 19) were calculated using the inverse-variance random effects model for meta-analyses. Estimates were also calculated for groups based on likely biological maturity status ("before", "during" and "after" peak height velocity). Using the standardised mean difference, resistance training increased strength across all groups (effect size = 0.98, [CI: 0.70-1.27]). Strength gains were larger during (1.11 [0.67-1.54]) and after (1.01 [0.56-1.46]) peak height velocity than before (0.5 [-0.06-1.07]). Adaptations to resistance training are greater in adolescent boys during or after peak height velocity. These findings should help coaches to optimise the timing of training programmes that are designed to improve strength in boy athletes.

Maturation-Related Effect of Low-Dose Plyometric Training on Performance in Youth Hockey Players.

PURPOSE: The purpose of this intervention study was to investigate if a low-dose of plyometric training (PT) could improve sprint and jump performance in groups of different maturity status. METHOD: Male youth field hockey players were divided into Pre-PHV (from -1 to -1.9 from PHV; Experimental: n = 9; Control = 12) and Mid-PHV (0 to +0.9 from PHV; Experimental: n = 8; Control = 9) groups. Participants in the experimental groups completed 60 foot contacts, twice-weekly for 6 weeks. RESULTS: PT exerted a positive effect (effect size: 0.4 [-0.4-1.2]) on 10 m sprint time in the experimental Mid-PHV group but this was less pronounced in the Pre-PHV group (0.1 [-0.6-0.9]). Sprint time over 30 m (Mid-PHV: 0.1 [-0.8-0.9]; Pre-PHV: 0.1 [-0.7-0.9]) and CMJ (Mid-PHV: 0.1 [-0.8-0.9]; Pre-PHV: 0.0 [-0.7-0.8]) was maintained across both experimental groups. Conversely, the control groups showed decreased performance in most tests at follow up. Between-group analysis showed positive effect sizes across all performance tests in the Mid-PHV group, contrasting with all negative effect sizes in the Pre-PHV group. CONCLUSION: These results indicate that more mature hockey players may benefit to a greater extent than less mature hockey players from a low-dose PT stimulus. Sixty foot contacts, twice per week, seems effective in improving short sprint performance in Mid-PHV hockey players.

The effects of lower-body compression garments on walking performance and perceived exertion in adults with CVD risk factors.

OBJECTIVES: Compression garments are used by athletes in attempts to enhance performance and recovery, although evidence to support their use is equivocal. Reducing the exertion experienced during exercise may encourage sedentary individuals to increase physical activity. The aim of this study was to assess the effect of compression garments on walking performance (self-paced and enforced pace) and rate of perceived exertion (RPE) in adults who presented with two or more CVD risk factors. Participants (n=15, 10 female, 58.9±11.5 years, BMI 27.5±4.5kgm2) were recruited. DESIGN: A repeated measures design. METHODS: Participants were randomised to Modified Bruce Protocol (enforced pace), or the 6min walk test (self-paced), and completed the test wearing compression garments or normal exercise clothes (Control). Outcome measures included stage completed, gross efficiency (%) and RPE in Modified Bruce Protocol, and distance walked (m) and RPE in 6 min walk test. RESULTS: In the Modified Bruce Protcol participants had a higher RPE (15.5±2.5 vs 14.3±2.2) and a lower efficiency (19.1±5.9 vs 21.1±6.7) in the compression garment condition compared with control, p<0.05. In the 6 min walk test participants walked 9% less in the compression garment condition (p<0.05) but did not have a lower RPE. CONCLUSIONS: Compared with previous studies reporting enhanced or no effects of compression garments on performance or RPE, this study shows adverse effects of such clothing in untrained individuals with CVD risk factors. The mechanisms underlying this negative effect require further exploration. Use of garments designed for the athletic individuals may not be suitable for the wider population.

Is Olympic inspiration associated with fitness and physical activity in English schoolchildren? A repeated cross-sectional comparison before and 18†months after London 2012.

OBJECTIVES: To compare cardiovascular fitness and physical activity of schoolchildren 18 months after London 2012 according to Olympic 'inspiration'. DESIGN: A cross-sectional comparison between groups of schoolchildren categorised according to self-reported Olympic inspiration and a repeated cross-sectional comparison using data collected pre-2012. SETTING: Schools within a 50 km radius of the Olympic Park, Stratford, London. PARTICIPANTS: 931 students (10.0-15.9-year-olds) attending 6 schools assessed in 2013 and 2014 (18 (range: 14-20) months after London 2012) and 733 students from the same schools assessed in 2008-2009 (42 (range: 38-46) months before London 2012). PRIMARY OUTCOME MEASURES: Self-reported Olympic inspiration; cardiorespiratory fitness ([Formula: see text] mL/kg/min) assessed using the 20 m shuttle-run and self-reported physical activity. SECONDARY OUTCOMES MEASURES: Differences in [Formula: see text] before and after London 2012. RESULTS: 53% of children reported being inspired to try new sports or activities. Compared with those not inspired by the Games, [Formula: see text] was higher in boys (d=0.43) and girls (d=0.27), who continued to participate in activities at 18(14-20) months. This 45% of sample was also more physically active (boys, d=0.23; girls, d=0.38) than those not or only briefly inspired to participate in activities (boys, d=0.24; girls, d=0.21). Compared with pre-2012 values, [Formula: see text] was lower post-2012 in boys (d=0.37) and in girls (d=0.38). CONCLUSIONS: High levels of inspiration to participate in new activities reported following London 2012 and positive associations with fitness are encouraging. We cannot discount the possibility that inspired participants may have already been fitter and more active pre-2012. These associations must be interpreted in the context of the significant declines in fitness shown by our repeated cross-sectional comparison. Olympic host countries should employ longitudinal monitoring using objectively measured fitness and physical activity to provide evidence of health-related legacy.

Media device ownership and media use: Associations with sedentary time, physical activity and fitness in English youth.

The aim of this study was to determine whether ownership and use of electronic media were associated with sedentary time and cardiorespiratory fitness (fitness) in youth. We also aimed to determine if associations were independent of physical activity (PA). Fitness was measured using the 20 m shuttle-run. PA, sedentary time, ownership of media devices and media use were self-reported. Participants (n = 678, age 10-15 years) reported daily sedentary time of 620 (± 210) min. Forty-one percent of participants had low PA and 50.4% had low fitness. Higher weekend sedentary time was associated with low fitness in girls (p = 0.005) and boys (p < 0.001) and remained significant when adjusted for PA in the latter (p = 0.006). Using social media was associated with higher sedentary time in both sexes and low fitness in girls. High sedentary time was more likely (OR = 5.3, 95%CI: 2.0-14.4) in boys who owned game consoles. Low fitness was more likely in boys who owned digital/satellite TV receivers (OR = 1.8, 95%CI: 1.8-3.2). Schoolchildren spent > 10 h or ~ 85% of each waking day sedentary. Use of social media was associated with higher sedentary time in both sexes and with low fitness in girls. Reducing social media use in youth offers one potential target for intervention. Behaviours associated with sedentary time differed from predictors of low fitness. The complex and often sex-specific interactions identified between sedentary time, PA and fitness suggest the need for carefully targeted interventions to reduce sedentary time and improve fitness in English youth.

Oxygen Costs of the Incremental Shuttle Walk Test in Cardiac Rehabilitation Participants: An Historical and Contemporary Analysis.

BACKGROUND: The incremental shuttle walk test (ISWT) is a standardised assessment for cardiac rehabilitation. Three studies have reported oxygen costs (VO2)/metabolic equivalents (METs) of the ISWT. In spite of classic representations from these studies graphically showing curvilinear VO2 responses to incremented walking speeds, linear regression techniques (also used by the American College of Sports Medicine [ACSM]) have been used to estimate VO2. PURPOSE: The two main aims of this study were to (i) resolve currently reported discrepancies in the ISWT VO2-walking speed relationship, and (ii) derive an appropriate VO2 versus walking speed regression equation. METHODS: VO2 was measured continuously during an ISWT in 32 coronary heart disease [cardiac] rehabilitation (CHD-CR) participants and 30 age-matched controls. RESULTS: Both CHD-CR and control group VO2 responses were curvilinear in nature. For CHD-CR VO2 = 4.4e0.23 × walkingspeed (km/h). The integrated area under the curve (iAUC) VO2 across nine ISWT stages was greater in the CHD-CR group versus the control group (p < 0.001): CHD-CR = 423 (±86) ml·kg-1·min-1·km·h-1; control = 316 (±52) ml·kg-1·min-1·km·h-1. CONCLUSIONS: CHD-CR group vs. control VO2 was up to 30 % greater at higher ISWT stages. The curvilinear nature of VO2 responses during the ISWT concur with classic studies reported over 100 years. VO2 estimates for walking using linear regression models (including the ACSM) clearly underestimate values in healthy and CHD-CR participants, and this study provides a resolution to this when the ISWT is used for CHD-CR populations.