No abstract

Background: Sedentary behaviour (SB) is a risk factor for chronic disease and premature mortality. While many individual studies have examined the reliability and validity of various self-report measures for assessing SB, it is not clear, in general, how self-reported SB (e.g., questionnaires, logs, ecological momentary assessments (EMAs)) compares to device measures (e.g., accelerometers, inclinometers). Objective: The primary objective of this systematic review was to compare self-report versus device measures of SB in adults. Methods: Six bibliographic databases were searched to identify all studies which included a comparable self-report and device measure of SB in adults. Risk of bias within and across studies was assessed. Results were synthesized using meta-analyses. Results: The review included 185 unique studies. A total of 123 studies comprising 173 comparisons and data from 55,199 participants were used to examine general criterion validity. The average mean difference was -105.19 minutes/day (95% CI: -127.21, -83.17); self-report underestimated sedentary time by~1.74 hours/day compared to device measures. Self-reported time spent sedentary at work was~40 minutes higher than when assessed by devices. Single item measures performed more poorly than multi-item questionnaires, EMAs and logs/diaries. On average, when compared to inclinometers, multi-item questionnaires, EMAs and logs/diaries were not significantly different, but had substantial amount of variability (up to 6 hours/day within individual studies) with approximately half over-reporting and half under-reporting. A total of 54 studies provided an assessment of reliability of a selfreport measure, on average the reliability was good (ICC = 0.66). Conclusions:Evidence from this review suggests that single-item self-report measures generally underestimate sedentary time when compared to device measures. For accuracy, multi-item questionnaires, EMAs and logs/diaries with a shorter recall period should be encouraged above single item questions and longer recall periods if sedentary time is a primary outcome of study. Users should also be aware of the high degree of variability between and within tools. Studies should exert caution when comparing associations between different self-report and device measures with health outcomes. Systematic review registration: PROSPERO CRD42019118755

The clinical phenotype of 45 genetically confirmed McArdle patients is described.In the majority of patients (84%), the onset of symptoms was from early childhood, but diagnosis was frequently delayed until after 30 years of age. Not all patients could recognise a second wind, although it was always seen with exercise assessment. A history of myoglobinuria was not universal, and episodes of acute renal failure had occurred in a minority (11%). The condition does not appear to adversely affect pregnancy and childbirth. Clinical examination was normal in most patients, muscle hypertrophy was present in 24% and mild muscle wasting and weakness was seen only in patients over 40 years of age and was limited to shoulder girdle and axial muscles. The serum creatine kinase (CK) was elevated in all but one pregnant patient. Screening for the mutations p.Arg50X (R50X) and p.Gly205Ser (G205S) showed at least one mutated allele in 96% of Caucasian British patients, with an allele frequency of 77% for p.Arg50X in this population. A 12-minute walking test to evaluate patients is described, results demonstrated a wide spectrum of severity with the range of distance walked being 195-1980 metres, the mean distance walked was 512m suggesting significant functional impairment in most patients.

Objectives: To evaluate the reliability and validity of measures taken during the Chester step test (CST) used to predict VO 2 max and prescribe subsequent exercise. Methods: The CST was performed twice on separate days by 7 males and 6 females aged 22.4 (SD 4.6) years. Heart rate (HR), ratings of perceived exertion (RPE), and oxygen uptake (VO 2 ) were measured at each stage of the CST. Results: RPE, HR, and actual VO 2 were the same at each stage for both trials but each of these measures was significantly different between CST stages (p,0.0005). Intertrial bias ¡95% limits of agreement (95% LoA) of HR reached acceptable limits at CST stage IV (22¡10 beats/min) and for RPE at stages III (0.2¡1.4) and IV (0.5¡1.9). Age estimated HRmax significantly overestimated actual HRmax of 5 beats/min (p = 0.016) and the 95% LoA showed that this error could range from an underestimation of 17 beats/min to an overestimation of 7 beats/min. Estimated versus actual VO 2 at each CST stage during both trials showed errors ranging between 11% and 19%. Trial 1 underestimated actual VO 2 max by 2.8 ml/kg/min (p = 0.006) and trial 2 by 1.6 ml/kg/min (not significant). The intertrial agreement in predicted VO 2 max was relatively narrow with a bias ¡95% LoA of 20.8¡3.7 ml/kg/min. The RPE and %HRmax (actual) correlation improved with a second trial. At all CST stages in trial 2 RPE:%HRmax coefficients were significant with the highest correlations at CST stages III (r = 0.78) and IV (r = 0.84). Conclusion: CST VO 2 max prediction validity is questioned but the CST is reliable on a test-retest basis. VO 2 max prediction error is due more to VO 2 estimation error at each CST stage compared with error in age estimated HRmax. The HR/RPE relation at .50% VO 2 max reliably represents the recommended intensity for developing cardiorespiratory fitness, but only when a practice trial of the CST is first performed.T he Chester step test (CST) was originally developed by Kevin Sykes at University College Chester to assess aerobic fitness by predicting maximal aerobic power (VO 2 max) in fire brigades in Britain, Europe, USA, and Asia, and more recently for work with airport firefighters, the ambulance service, health authorities, and corporate institutions.1 It also features in commercial health and fitness assessment packages and most noticeably one in particular (Fitech Pty Ltd, Australia; www.fitech.com.au). The CST is one of many tests designed to provide a safe and practical means of assessing aerobic fitness under submaximal conditions. Examples of other similar tests include the Astrand-Ryhming nomogram cycle ergometer protocol, 2 the American College of Sports Medicine protocols for cycle ergometry and treadmill, 3 and the Canadian standardised step test of fitness. 4 The limited equipment needed (step, heart rate monitor, portable cassette or compact disk player, and perceived exertion scale) makes the CST very portable and requirements for space are minimal, which is advantageous compared with similar protocols using treadmills, shutt...

This is the first known 'office-based' study to provide CGM measures that add some of the needed mechanistic information to the existing evidence-base on why avoiding sedentary behaviour at work could lead to a reduced risk of cardiometabolic diseases.

No abstract

No abstract

This study is the first to apply Borg's psychophysical equation to measuring responses to strength training with weights machines. Theoretical constructs of Borg's scales were assessed in younger and older adults to estimate the appropriate load and number of repetitions required to meet recommended practice guidelines. A younger group (YG; 20 males, 20 females; aged 19-38 years) and older group (OG; 13 males, 13 females; aged 50-75 years) participated in 3 experiments. Experiment 1: YG performed 2-repetitions of incremented loads during triceps-elbow extensions and knee extensions to level 7 on Borg's CR10 Scale. Experiment 2: YG (n = 16) then performed 12-repetitions at the loads from experiment 1 that elicited CR10 ratings 1.5, 3.0, and 5.0. Experiment 3: OG performed 15-repetitions of "lat-pull" and leg press at 15-repetition maximum (RM) load. In experiments 2 and 3, CR10 or Borg RPE were measured every 2 repetitions. Experiment 1 revealed classic psychophysical response growth exponents between 1.1 and 1.8, which were greater in arms than legs (p < 0.001) and in females (p < 0.001). Theoretical estimates of 1RM were derived from the growth curves for the weights eliciting CR10 ratings of 1.5, 3, and 5. CR10 ratings of 3 to 6 fell within estimates of 40%-70% 1RM. Experiments 2 and 3 revealed, for constant load exercise "over time" (12 and 15 repetitions) from an initial CR10 rating of 4 to 6, a linear increase of 1 scale point for every 3 to 4 repetitions. In conclusion, Borg's equation has been used to set theoretical estimates of a %1RM. Relevant to current practice guidelines was the ability to set appropriate loads in relation to performing recommended numbers of repetitions (e.g., if the CR10 rating is >6 after 2 repetitions, the weight is likely be too heavy to complete 12 to 15 repetitions).