Maximal physiological responses to deep and shallow water running.

The maximal physiological responses to treadmill running (TMR), shallow water running (SWR) and deep water running (DWR) while wearing a buoyancy vest were compared in 15 trained male runners. Measurements included oxygen consumption (VO2 max), respiratory exchange ratio (RER) and heart rate (HR). Treadmill running elicited VO2 max and HRmax, which were higher than the peaks attained in both water tests (p < 0.01). VO2 peak averaged 83.7 and 75.3% of VO2 max for SWR and DWR respectively. Peak HR for SWR and DWR were 94.1 and 87.2% of the HRmax reached in the TMR. RER responses were similar between the three modalities. The observations suggest that the training stimulus provided by water is still adequate for supplementary training. While SWR is potentially an efficient method of maintaining cardiovascular fitness, it needs to be investigated further to establish if it is a viable technique for the injured athlete to employ

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

This is an accepted manuscript of an article published by Taylor & Francis in Journal of Sports Sciences on 13/05/2020, available online: https://doi.org/10.1080/02640414.2020.1756682 The accepted version of the publication may differ from the final published version.© 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group. 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.Published versio

Evaluation and assessment of the usefulness of a mail delivered personalised diabetes information booklet and the association of non-response with clinical risk: the WICKED Project

Introduction: Patient activation can promote partnership working between people with diabetes and their healthcare professionals. We sent to people with diabetes a personalised, structured information booklet containing the results of their latest nine key care processes in order to inform and activate them. We present the findings of a survey to assess the utility of this report, with an analysis of the association of non-response to the survey, a surrogate for poorer patient activation, with adverse diabetes and clinical outcomes. Methods: All 14,559 people with diabetes in the Wolverhampton health economy received a mailed report of the results of their latest nine diabetes care processes. Of these, 6,282 patients aged <75 years were mailed this report twice; 1000 of these 6,282 patients were selected randomly to receive a structured questionnaire to assess the report’s effectiveness. Results: Of 1,000 patients, 419 (42%) responded (mean age 62±10 years, 246 males, 249 Caucasians, 389 had type 2 diabetes). Patients found this report useful (89%), a source of knowledge (78%), a source of increased confidence (74%) and it helped them understand their diabetes (78%). Non-response was associated with significantly higher surrogate markers of micro- and macrovascular risk. Conclusion: A structured and personalised diabetes report, without direct professional or health service intervention, may improve the understanding and confidence of people with diabetes in their self-care and it may help to activate them to take a stronger partnership role in their health care. Non-response as a marker of patient activation is associated with increased clinical risk

Reproducibility of body volume assessments in survival clothing in fixed and portable scanning systems.

The recent development of portable 3D scanning systems for industries such as animation and museum artefact digitisation have considerable potential for applications involving human body measurement. However, this requires a system for validation of measurements against a criterion, which this study aimed to provide. Forty four adult males were scanned in duplicate in both a fixed Hamamatsu and portable Artec L scanning systems in two postures and two different clothing assemblages. Following inspection of all scans, complete data for duplicate scans of 38 participants were available for the study. Both scanners demonstrated good precision, however significant differences in body volume prevailed for both egress and scanner postures in form-fitting clothing and the scanner posture in survival suit scans, with the Hamamatsu providing greater volumes than the Artec system (by 2.7, 2.8 and 2.1 litres respectively). Regression analysis indicated the results from the portable scanner explained between 96 and 98% of the variability in the results from the fixed scanner. The biases in body volume probably relate to different software approaches to its calculation, and a possible interaction with posture and clothing. Validation of the Artec against the Hamamatsu system provides valuable information for its use in field and industrial settings

Modelling effects of drug testing procedures on performance trends in the shot put

Objectives: The effect of performance enhancing drugs on historic performance records in sport is open to interpretation and needs empirical support. Here we addressed this contentious issue by assessing whether a double sigmoidal model could detect decrements in sporting performance attributed to introduction of drug testing protocols. Methods: Distances thrown by the top 25 male and female shot putters since the end of the 19th century were modelled using a double sigmoid. Results: First-phase peak acceleration in the men’s and women’s shot put was reached in 1981 and 1986 respectively coinciding with advent of systematic doping programs. Shot put performance of men and women underwent a second-phase decline of 5.3 m and 8.9 m, in 1991 and 1994, respectively. Performance decrements in women’s shot put were nearly double that for men, but much of this difference resulted from the reduced mass of their shot. Controlling for changes in mass, women’s shot put performance appears to decline to a greater extent than men’s, based on raw energy calculations. Conclusions: The double sigmoidal model detected a second-phase decline in shot put performances. We attribute this data feature to onset of improved drug testing protocols and a consequential reduction of doping. The assumption is that drug testing programs of shot putters has been successful and reduced the prevalence of drug taking in that sport. The application of a double sigmoidal model to historic performance statistics can be used to detect unknown interventions in analyses of sports performance.</p

The dangers of estimating V˙O2max using linear, nonexercise prediction models

Purpose This study aimed to compare the accuracy and goodness of fit of two competing models (linear vs allometric) when estimating V˙O2max (mL·kg−1·min−1) using nonexercise prediction models. Methods The two competing models were fitted to the V˙O2max (mL·kg−1·min−1) data taken from two previously published studies. Study 1 (the Allied Dunbar National Fitness Survey) recruited 1732 randomly selected healthy participants, 16 yr and older, from 30 English parliamentary constituencies. Estimates of V˙O2max were obtained using a progressive incremental test on a motorized treadmill. In study 2, maximal oxygen uptake was measured directly during a fatigue limited treadmill test in older men (n = 152) and women (n = 146) 55 to 86 yr old. Results In both studies, the quality of fit associated with estimating V˙O2max (mL·kg−1·min−1) was superior using allometric rather than linear (additive) models based on all criteria (R2, maximum log-likelihood, and Akaike information criteria). Results suggest that linear models will systematically overestimate V˙O2max for participants in their 20s and underestimate V˙O2max for participants in their 60s and older. The residuals saved from the linear models were neither normally distributed nor independent of the predicted values nor age. This will probably explain the absence of a key quadratic age2 term in the linear models, crucially identified using allometric models. Not only does the curvilinear age decline within an exponential function follow a more realistic age decline (the right-hand side of a bell-shaped curve), but the allometric models identified either a stature-to-body mass ratio (study 1) or a fat-free mass-to-body mass ratio (study 2), both associated with leanness when estimating V˙O2max. Conclusions Adopting allometric models will provide more accurate predictions of V˙O2max (mL·kg−1·min−1) using plausible, biologically sound, and interpretable models

Salivary biomarkers and training load during training and competition in paralympic swimmers

CONTEXT: Stress responses in athletes can be attributed to training and competition, where increased physiological and psychological stress may negatively affect performance and recovery. PURPOSE: To examine the relationship between training load (TL) and salivary biomarkers immunoglobulin A (IgA), alpha-amylase (AA), and cortisol across a 16-wk preparation phase and 10-d competition phase in Paralympic swimmers. METHODS: Four Paralympic swimmers provided biweekly saliva samples during 3 training phases-(1) normal training, (2) intensified training, and (3) taper-as well as daily saliva samples in the 10-d Paralympic competition (2016 Paralympic Games). TL was measured using session rating of perceived exertion. RESULTS: Multilevel analysis identified a significant increase in salivary immunoglobulin A (sIgA: 94.98 [27.69] μg·mL-1), salivary alpha-amylase (sAA: 45.78 [19.07] μg·mL-1), and salivary cortisol (7.92 [2.17] nM) during intensified training concurrent with a 38.3% increase in TL. During the taper phase, a 49.5% decrease in TL from the intensified training phase resulted in a decrease in sIgA, sAA, and salivary cortisol; however, all 3 remained higher than baseline levels. A further significant increase was observed during competition in sIgA (168.69 [24.19] μg·mL-1), sAA (35.86 [16.67] μg·mL-1), and salivary cortisol (10.49 [1.89] nM) despite a continued decrease (77.8%) in TL from the taper phase. CONCLUSIONS: Results demonstrate that performance in major competition such as Paralympic games, despite a noticeable reduction in TL, induces a stress response in athletes. Because of the elevated stress response observed, modifications to individual postrace recovery protocols may be required to enable athletes to maximize performance across all 10 d of competition