Change in heart rate variability during two firefighting work cycles.

This study aimed to determine whether the change in heart rate variability from pre to post firefighting is modulated by different work cycles. Thirteen male firefighters underwent two firefighting simulations that comprised two identical 25-min work bouts intercalated by a passive recovery period of either 20 min (T20) or 5 min (T5). The square root of the mean squared differences of successive R-R intervals (RMSSD) and aural temperature were measured at rest before (PRE) and after (POST) firefighting simulations. The decrease in RMSSD was different between firefighting simulations (T20: -10 ± 21.2 ms, T5: -19.9 ± 20.9 ms, interaction, p = 0.02). Post-firefighting aural temperature was greater (p = 0.05) in T5 (37.18 ± 0.53 °C) than in T20 (36.88 ± 0.49 °C). In conclusion, a shorter recovery period of 5 min between firefighting work bouts decreases post-firefighting heart rate variability, possibly attributed to a lower parasympathetic reactivation and a higher absolute value of body temperature.

Analysis of proportions using arcsine transform with any experimental design.

Introduction: Exact tests on proportions exist for single-group and two-group designs, but no general test on proportions exists that is appropriate for any experimental design involving more than two groups, repeated measures, and/or factorial designs. Method: Herein, we extend the analysis of proportions using arcsine transform to any sort of design. The resulting framework, which we have called Analysis of Proportions Using Arcsine Transform (ANOPA), is completely analogous to the analysis of variance for means of continuous data, allowing the examination of interactions, main and simple effects, post-hoc tests, orthogonal contrasts, et cetera. Result: We illustrate the method with a few examples (single-factor design, two-factor design, within-subject design, and mixed design) and explore type I error rates with Monte Carlo simulations. We also examine power computation and confidence intervals for proportions. Discussion: ANOPA is a complete series of analyses for proportions, applicable to any design.

Vascular Assessment in Patients With a Lower Limb Wound: A Correlational Study of Photoplethysmography and Laser Doppler Flowmetry Toe Pressure Techniques.

BACKGROUND: Vascular assessment of the lower limbs is essential in patients with diabetes. In the presence of noncompressible arteries, the ankle brachial index (ABI) can either be inconclusive or provide false-positive results. Toe pressure measurement has been suggested as an alternative as a noninvasive method for detecting peripheral arterial disease (PAD). Toe pressure measurement can be performed either by photoplethysmography (PPG) or by Laser Doppler flowmetry (LDF). The aim of this study was to determine correlations between the two techniques in order to promote the use of PPG in clinical practice. METHODS: This was a prospective correlational study of 108 consecutive recruited adult patients, with and without diabetes, with at least one lower limb wound from a University-affiliated hospital wound care clinic. Toe pressure measurements were both performed with PPG and LDF devices. RESULTS: Mean toe pressure values for PPG and LDF were, respectively, 83.7 (SD 35.4) and 79.5 (SD 32.0) mmHg (with a paired t-test 3.969, P < 0.01). In patients with at least one lower limb wound, a strong linear relation was found between PPG and LDF toe pressure techniques with a Pearson's r correlation coefficient of 0.920 (P < 0.001). CONCLUSIONS: PPG and LDF toe pressure techniques are equivalent in patients with at least one lower limb wound, irrespective of the presence of diabetes. Therefore, in the presence of an ABI with inconclusive results, such as in a patient with noncompressible vessels, both toe pressure techniques can be used for assessing the vascular supply of the lower limb with a wound.

Former athletes' lifestyle and self-definition changes after retirement from sports.

BACKGROUND: Every high-level athlete will eventually see his or her sport career come to an end. Most former athletes will experience changes in their self-definition and everyday behaviors as they accept a nonathletic way of life. The present study aimed to identify discrepancies between actual and former athletes regarding athletic identity, physical activity (PA), and nutrition habits. METHODS: Actual athletes (AA; n = 122), former athletes (FA; n = 230), and nonathletes (NA; n = 74) were asked to complete an online questionnaire on athletic identity, duration and intensity levels of occupational and leisure time PA, and nutritional habits. RESULTS: FA healthy nutrition score was the lowest of the 3 groups and significantly different from that of AA. Athletic identity and intense and moderate PA during leisure time consistently decreased (p < 0.01) across the 3 groups (AA > FA > NA). No significant difference between FA and NA was found regarding either nutritional habits or type of PA. CONCLUSION: Sport retirement may affect FA quality of nutritional habits that tends to decline below the NA level, as well as the amount of time spent practicing physical activities during leisure time. Athletic status does not ensure PA practice during sport postcareer.

Shortened Recovery Period Between Firefighting Work Bouts Increases Cardiac Response Disproportionately With Metabolic Rate.

OBJECTIVE: To compare physiological responses between two firefighting simulations with different recovery periods, one having work bouts intercalated by a shortened recovery period. METHODS: Thirteen male firefighters participated in two different simulations, which comprised two identical 25-minute effort bouts (E1 and E2) intercalated by a recovery period of either 20 (T20) or 5 (T5) minutes. RESULTS: From E1 to E2, the increase of mean heart rate (HR) (26 ±â€Š5 vs 14 ±â€Š5 bpm, P < 0.001) and mean VO2 (1.8 ±â€Š0.4 vs 1.3 ±â€Š0.4 mL kg min, P < 0.001) was higher in T5 than in T20. CONCLUSION: Results indicate that a shortened recovery time between firefighting work bouts intensifies cardiac strain disproportionately with metabolic rate, since mean HR increased by 19.3% and 10.8% while mean VO2 increased by only 7.2% and 5.0% in T5 and T20, respectively.

Cardiovascular health profile among Québec male and female police officers.

To document the cardiovascular health profile of Québec police officers (PO). Participants answered an online questionnaire evaluating the presence of cardiovascular disease (CVD) risk factors and symptoms. Two thousand, ninety-nine (2,099) male (age: 40.8 ± 9.2 years) and 756 female (age: 37.9 ± 7.9 years) PO participated in this study. The prevalence of obesity (body mass index ≥30 kg/m2) and diagnosed hypertension was respectively 21.1, and 14.3% in male and 7.3 and 4.1% in female PO. According to 2013 American College of Sports Medicine guidelines, 27.0 and 48.0% of male and 12.1 and 56.7% of female PO were categorized as being at moderate and high CVD risk, respectively. These findings suggest that Québec police departments should help PO to adopt and maintain a healthy lifestyle to decrease CVD risk.

Quantification of joint alignment and stability during a single leg stance task in a knee osteoarthritis cohort.

BACKGROUND: Knee osteoarthritis alters joint stability but its kinematics during functional weight-bearing tasks remain unclear. We propose and validate an assessment technique for the quantification of knee alignment and stability in patients during a short single leg stance task. METHODS: Three-dimensional knee kinematics were acquired non-invasively from 31 knee osteoarthritis patients (subdivided as moderate or severe) and 15 asymptomatic individuals during six short single-leg stance tasks. Data of participants achieving ≥3 trials were retained. From flexion-extension signals, a data treatment method compared the average between-trial root-mean-square error (RMSE) across trial triplets, and the average within-trial range of movement (RoM) for two data windows. From secondary knee motions (ab/adduction and int/external rotations, anteroposterior and mediolateral translations), we extracted measures characterizing alignments (mean), largest deviations (maximum, minimum), and extent of micro-adjustments (RoM, length of knee excursion). Their sensitivity to disease and severity was determined using an ANOVA, and between-trial repeatability using ICC2,3. RESULTS: Ninety-four percent of patients achieved ≥3 trials. The retained trial triplet and window reduced the RMSE (2.15 to 1.54) and RoM (4.9° to 1.77°) for flexion-extension. Mean, minimum, and maximum measures were sensitive to disease for anteroposterior translations, and to severity for ab/adduction (P < 0.05). High repeatability was found for those measures (ICC ≥0.84). RoM and length of knee excursion, although sensitive to disease for anteroposterior translations, had lower ICC. CONCLUSION: The proposed technique is feasible and exposed measures of knee alignment sensitive to knee osteoarthritis, for instance, an anterior femoral shift and an increased adduction malalignment with greater severity.

Barriers identification as intervention to engage breast cancer survivors in physical activity / La identificación de barreras como intervención para involucrar a supervivientes de cáncer de mama en actividades físicas

This study was designed to demonstrate the advantage of adding cancer barriers to components of decision-making in the transtheoretical model (TTM). In study 1, questionnaires were completed by 139 breast cancer survivors including decisional balance, cancer-related barriers and stages of readiness. In study 2, efficiency of directly tackling cancer-related barriers through motivational-style conversation was tested in a quasi-experimental design. From study 1, all decision-making variables were related to stages of readiness, but cancer-related barriers were the sole predictors of engagement in physical activity. Out of the three groups of study 2, only the group with motivational-style conversation displayed a significant progress for engagement in physical activity. Demonstrating that cancer-related barriers predict stage of change above the effects of the two components of decisional balance provides a validation of positions that put cancer-related barriers as uniquely related to stages of change, and suggests that adding them in decision making variables in TTM’s model can provide a genuinely new contribution to the understanding of physical activity adherence. Regarding implication for cancer survivors, these results suggest that in order to stimulate progress in early stages of change, a greater emphasis may be needed on reducing cancer-related barriers

Este estudio fue diseñado para demostrar las ventajas de tener en cuenta las barreras relacionadas con el cáncer en el proceso de toma de decisiones en el modelo transteórico. En el estudio 1 los cuestionarios fueron respondidos por 139 supervivientes de cáncer de mama, en ellos se incluyó el equilibrio decisional, las barreras relacionadas con el cáncer y las etapas de preparación. En el estudio 2 la eficacia de abordar las barreras relacionadas con el cáncer a través de conversaciones de tipo motivacional se puso a prueba con un diseño cuasi-experimental. En el estudio 1 todas las variables de toma de decisiones se relacionaron con las etapas de preparación, pero las barreras relacionadas con el cáncer fueron los únicos predictores de la participación en la actividad física. De los tres grupos del estudio 2, sólo el grupo con conversación de tipo motivacional mostró un progreso significativo para la participación en la actividad física. Demostrar que las barreras relacionadas con el cáncer predicen la etapa de cambio sobre los efectos de los dos componentes del equilibrio decisional proporciona apoyo a la idea de que las barreras relacionadas con el cáncer se encuentran relacionadas con las etapas de cambio y sugiere que su incorporación al proceso de toma de decisiones en el modelo transteórico puede proporcionar una contribución nueva y significativa a la comprensión de la adherencia a la actividad física. Con respecto a las implicaciones para supervivientes de cáncer, estos resultados sugieren que para estimular el progreso en las primeras etapas de cambio, puede ser necesario un mayor énfasis en la reducción de las barreras relacionadas con el cáncer

Cardiovascular Disease Risk Factors in Québec Male Firefighters.

OBJECTIVE: We aimed to document the prevalence of cardiovascular disease (CVD) risk factors and symptoms in Québec firefighters. METHODS: Seven hundred and seventy-nine (779) male firefighters (age: 41.6 ±â€Š10.4 years; body mass index [BMI]: 28.0 ±â€Š3.6 kg/m) answered an online questionnaire evaluating lifestyle and the presence of CVD risk factors and symptoms. RESULTS: The prevalence of obesity (BMI is more than or equal to 30 kg/m), diagnosed hypertension, diagnosed dyslipidemia, and diagnosed type 2 diabetes mellitus was respectively 23.6%, 12.2%, 17.4%, and 1.7%. Among survey participants, 34.5% were categorized as moderate and 43.6% as high CVD risk, according to American College of Sports Medicine guidelines. CONCLUSIONS: A high proportion of Québec firefighters are at moderate to high risk of CVD. These findings suggest that Québec fire departments should help all firefighters to adopt and maintain a healthy lifestyle.

An Unbiased Estimate of Global Interrater Agreement.

Assessing global interrater agreement is difficult as most published indices are affected by the presence of mixtures of agreements and disagreements. A previously proposed method was shown to be specifically sensitive to global agreement, excluding mixtures, but also negatively biased. Here, we propose two alternatives in an attempt to find what makes such methods so specific. The first method, RB , is found to be unbiased while at the same time rejecting mixtures, is detecting agreement with good power and is little affected by unequal category prevalence as soon as there are more than two categories.

Effect of Sequencing Strength and Endurance Training in Young Male Soccer Players.

This study examined the effects of strength and endurance training sequence (strength before or after endurance) on relevant fitness variables in youth soccer players. Fifty-seven young elite-level male field soccer players (13.7 ± 0.5 years; 164 ± 8.3 cm; 53.5 ± 8.6 kg; body fat; 15.6 ± 3.9%) were randomly assigned to a control (n = 14, CG) and 3 experimental training groups (twice a week for 12 weeks) strength before (SE, n = 15), after (ES, n = 14) or on alternate days (ASE, n = 14) with endurance training. A significant (p = 0.001) intervention main effect was detected. There were only trivial training sequence differences (ES vs. SE) for all variables (p > 0.05). The CG showed large squat 1 repetition maximum (1RM) and medium sprint, change of direction ability, and jump improvements. ASE demonstrated a trivial difference in endurance performance with ES and SE (p > 0.05). Large to medium greater improvements for SE and ES were reported compared with ASE for sprinting over 10 and 30 m (p < 0.02). The SE squat 1RM was higher than in ASE (moderate, p < 0.02). Postintervention differences between ES and SE with CG fitness variables were small to medium (p ≤ 0.05) except for a large SE advantage with the Yo-Yo intermittent recovery test (p < 0.001, large). This study showed no effect of intrasession training sequence on soccer fitness-relevant variables. However, combining strength and endurance within a single training session provided superior results vs. training on alternate days. Concurrent training may be considered as an effective and safe training method for the development of the prospective soccer player.

A correction factor for the impact of cluster randomized sampling and its applications.

Cluster randomized sampling is 1 method for sampling a population. It requires recruiting subgroups of participants from the population of interest (e.g., whole classes from schools) instead of individuals solicited independently. Here, we demonstrate how clusters affect the standard error of the mean. The presence of clusters influences 2 quantities, the variance of the means and the expected variance. Ignoring clustering produces spurious statistical significance and reduces statistical power when effect sizes are moderate to large. Here, we propose a correction factor. It can be used to estimate standard errors and confidence intervals of the mean under cluster randomized sampling. This correction factor is easy to integrate into regular tests of means and effect sizes. It can also be used to determine sample size needed to reach a prespecified power. Finally, this approach is an easy-to-use alternative to linear mixed modeling and hierarchical linear modeling when there are only 2 levels and no covariates.

Chronic low back pain clinical outcomes present higher associations with the STarT Back Screening Tool than with physiologic measures: a 12-month cohort study.

BACKGROUND: Stratification strategies based on identifying patient's prognosis in order to guide patient care constitute one of the most prominent and recent approach in low back pain research. The STarT Back Screening Tool (SBST) although promising, has not been studied in patients with chronic low back pain (cLBP). Considering how challenging it is to translate research into practice, the value of integrating a new tool should be thoroughly assessed. The purpose was therefore to assess associations between the short- and long-terms clinical status and two types of variables, physiologic measures and the SBST, in participants with cLBP. The ability of both types of variables to discriminate between participants with and without higher levels of disability, pain, fear of movement and patient's global impression of change was also investigated. METHODS: Fifty-three volunteers with cLBP participated in an initial evaluation and follow-ups at 2-, 4-, 6- and 12-month. Physiologic measures (maximal voluntary contraction, maximal endurance and muscle activity evaluated during prone and lateral isometric tasks) and the SBST were assessed at baseline. Disability (Oswestry Disability Index, ODI), pain intensity (101-point Numerical Rating Scale, NRS), fear of movement (Tampa Scale for Kinesiophobia, TSK) and patient's global impression of change (7-point scale, PGIC) were evaluated at baseline and at each follow-up. Aside the use of correlation analyses to assess potential associations; ROC curves were performed to evaluate the discriminative ability of physiologic measures and the SBST. RESULTS: The SBST allowed for the identification of participants presenting higher levels of disability (ODI ≥24 %), pain (NRS ≥37 %) or fear of movement (TSK ≥41/68) over a 12-month period (AUC = 0.71 to 0.84, ps < 0.05). The SBST score was also correlated with disability at each follow-up (τ = 0.22 to 0.33, ps < 0.05) and with pain intensity and fear of movement at follow-ups. Among physiologic measures, only maximal voluntary contraction was correlated to disability, pain intensity or fear of movement during the follow-up (|τ| = 0.26 to 0.32, ps < 0.05) and none was able to identify participants presenting higher levels of outcomes (AUC ps > 0.05). CONCLUSION: Physiologic measures obtained during prone and lateral tests have limited associations with the clinical status over a 12-month period in patients with nonspecific chronic low back pain. On the other hand, the STarT Back Screening Tool is useful for the identification of patients who will present higher levels of disability, pain intensity and fear of movement over a year. TRIAL REGISTRATION: Clinicaltrials.gov NCT02226692.

Energy expenditure at work in physical education teachers.

The objective of this study was to quantify work energy expenditure (EE) in physical education (PE) teachers. Sixty-four (64) physical educators (49 men, 15 women) had their individualized linear function between heart rate (HR) and oxygen consumption measured by laboratory testing. HR was then recorded on 2 different days at work to estimate EE, correlated with a diary of daily tasks. Average absolute EE was low-to-moderate (2.7 ± 1.4 to 4.6 ± 2.5 kcal·min(-1)) and low when expressed in relative values (15.3 ± 6.1% to 24.8 ± 7.6% of VO2max). However, these physical educators often reached very high intensities (from 7.5 ± 7.9% to 23.8 ± 22.3% of work time at 100 bpm and more). PE teaching requires a light-to-moderate EE with more intense periods of physical activity. The variety of tasks performed (office work, supervision and monitoring, mixed participation and active participation) significantly influenced EE.

A Ratio Test of Interrater Agreement With High Specificity.

Existing tests of interrater agreements have high statistical power; however, they lack specificity. If the ratings of the two raters do not show agreement but are not random, the current tests, some of which are based on Cohen's kappa, will often reject the null hypothesis, leading to the wrong conclusion that agreement is present. A new test of interrater agreement, applicable to nominal or ordinal categories, is presented. The test statistic can be expressed as a ratio (labeled QA , ranging from 0 to infinity) or as a proportion (labeled PA , ranging from 0 to 1). This test weighs information supporting agreement with information supporting disagreement. This new test's effectiveness (power and specificity) is compared with five other tests of interrater agreement in a series of Monte Carlo simulations. The new test, although slightly less powerful than the other tests reviewed, is the only one sensitive to agreement only. We also introduce confidence intervals on the proportion of agreement.

Life transitions in the waning of physical activity from childhood to adult life in the Trois-Rivières study.

BACKGROUND: Several studies have reported an age-related decline of physical activity (PA). We examined the impact of 4 important transitional periods-adolescence, the beginning of postsecondary education, entry into the labor market, and parenthood-on the PA of participants in the Trois-Rivières quasi-experimental study. METHODS: In 2008, 44 women and 42 men aged 44.0 ± 1.2 years were given a semistructured interview; the frequency and duration of physical activities were examined during each of these transition periods. Subjects had been assigned to either an experimental program [5 h of weekly physical education (PE) from Grades 1 to 6] or the standard curriculum (40 min of weekly PE) throughout primary school. RESULTS: The percentage of individuals undertaking ≥ 5 h of PA per week decreased from 70.4% to 17.0% between adolescence and midlife. The largest decline occurred on entering the labor market (from 55.9% to 23.4%). At midlife, there were no significant differences of PA level between experimental and control groups. Men were more active than women at each transition except for parenthood. CONCLUSIONS: Our results highlight a progressive nonlinear decline of PA involvement in both groups. Promotion initiatives should target these periods to prevent the decline of PA.

Intermittent endurance and repeated sprint ability in soccer players.

The ability to perform high-intensity intermittent exercise (i.e., Yo-Yo Intermittent Recovery Test [Yo-Yo IR1]) and to repeat sprints with relatively short recovery times (i.e., 20- to 30-seconds, relatively short time interval [repeated sprint ability (RSA)]) has been shown to be relevant fitness variables in soccer. However, though they potentially share common features, it is not known whether these 2 abilities are associated. The aim of this study was to examine the relationships between Yo-Yo IR1 and RSA performances in elite soccer players. Twenty-three soccer players (age 19 ± 1 years, height 181 ± 5.7 cm, body mass 73.2 ± 4.1 kg, %body fat 11 ± 2.4) performed the Yo-Yo IR1 and a test for RSA (7 × 30 m with 25-second recovery). Results were 2,289 ± 409 m, 31.21 ± 1.13 seconds, and 4 ± 2.1% for Yo-Yo IR1, total sprint time, and sprint decrement, respectively. Yo-Yo IR1 showed a significant and moderate relationship with sprint decrement (r² = -0.44, p = 0.04). Splitting the sample into Best and Worst Yo-Yo IR1 performers according to median score (2,320 m), the Best group showed lower RSA total time (30.69 ± 0.99 vs. 31.79 ± 1.06, p < 0.05) and speed decrement (2.90 ± 0.86 vs. 5.09 ± 2.42, p < 0.01) compared to the Worst group. Sprint-time deterioration over 30 m occurred earlier (from the second sprint on) in the Yo-YoWorst compared with in the Yo-YoBest group (from the fourth sprint on, p < 0.001). Intermittent high-intensity endurance is poorly associated with RSA performance (r² = 0.19). Consequently, coaches and strength and conditioning professionals should consider both Yo-Yo IR1 and RSA in their testing batteries. A Yo-Yo IR1 performance ≥2,320 m could be considered as a reasonable indicator of physical fitness in elite soccer. Relatively short time interval test protocols similar to the present study should consist of at least 5 sprint bouts.

Career changes among physical educators: searching for new goals or escaping a heavy task load?

Physical educators experience several occupational constraints and a high risk of physical injury associated with a high attrition rate. Our investigation aimed at identifying the principal career reorientation factors among physical educators and reasons for their career changes. This research used semistructured interviews (n = 53) that were analyzed qualitatively and quantitatively. While younger teachers frequently invoked job precariousness, the more experienced teachers and those who made a transition toward other teaching functions put more emphasis on teaching problems, work conditions, and physical context. Those who transferred toward administrative duties insisted on their desire for a new challenge. Our study indicates that career reorientation is most often associated with job precariousness and the pursuit of new challenges, respectively, for younger and older physical educators.

Diagnostic Imaging Guidelines Implementation Study for Spinal Disorders: A Randomized Trial with Postal Follow-ups.

PURPOSE: Implementation strategies of imaging guidelines can assist in reducing the number of radiographic examinations. This study aimed to compare the perceived need for diagnostic imaging before and after an educational intervention strategy. METHODS: One hundred sixty Swiss chiropractors attending a conference were randomized to either receive a radiology workshop, reviewing appropriate indications for diagnostic imaging for adult spine disorders (n = 80), or be in a control group (CG). One group of 40 individuals dropped out from the CG due to logistic reasons. Participants in the intervention group were randomly assigned to three subgroups to evaluate the effect of an online reminder at midpoint. All participants underwent a pretest and a final test at 14-16 weeks. A posttest was administered to two subgroups at 8-10 weeks. RESULTS: There was no difference between baseline scores, and overall scores for the pretest and the final tests for all four groups were not significantly different. However, the subgroup provided with access to a reminder performed significantly better than the subgroup with whom they were compared (F = 4.486; df = 1 and 30; p = .043). Guideline adherence was 50.5% (95% CI, 39.1-61.8) for the intervention group and 43.7% (95% CI, 23.7-63.6) for the CG at baseline. Adherence at follow-up was lower, but mean group differences remained insignificant. CONCLUSIONS: Online access to specific recommendations while making a clinical decision may favorably influence the intention to either order or not order imaging studies. However, a didactic presentation alone did not appear to change the perception for the need of diagnostic imaging studies.

Influence of birth quarter on the rate of physical activities and sports participation.

The purpose of this study was to assess the potential influence of birth quarter on the frequency of physical activity and participation in specific activities during adulthood. We used data from one national and one provincial survey, the 2005 Canadian Community Health Survey and the 1998 Quebec Social and Health Survey (Enquête sociale et de santé du Québec) respectively. We analysed the distribution of participants at each level of practice of a given leisure activity and work-related physical activity. In the Canadian Community Health Survey, a relative age effect was found for participation in soccer in the 25- to 60-year-old population. However, for volleyball, a significant relative age effect was also observed but with over-representation of the last quarters of the year for the whole population and for men aged 12-60 years. In the Quebec Social and Health Survey, significant differences in the frequency of distribution without a relative age effect were revealed for participation in women's ice hockey, work-related physical activity level, and stage of change for physical activity. Overall, the data indicate that the systematic relative age effect reported in other studies for some competitive sports, such as ice hockey and soccer, is not as prevalent in leisure physical activities during adulthood. This may reflect lower competitive selection and attrition in population physical activity compared with competitive sports in younger athletes.