Multiple propane gas burn rates procedure to determine accuracy and linearity of indirect calorimetry systems: an experimental assessment of a method.

Objective: Indirect calorimetry (IC) systems measure the fractions of expired carbon dioxide (FeCO2), and oxygen (FeO2) recorded at the mouth to estimate whole-body energy production. The fundamental principle of IC relates to the catabolism of high-energy substrates such as carbohydrates and lipids to meet the body's energy needs through the oxidative process, which are reflected in the measured oxygen uptake rates (V̇O2) and carbon dioxide production rates (V̇CO2). Accordingly, it is important to know the accuracy and validity of V̇O2and V̇CO2 measurements when estimating energy production and substrate partitioning for research and clinical purposes. Although several techniques are readily available to assess the accuracy of IC systems at a single point for V̇CO2 and V̇O2, the validity of such procedures is limited when used in testing protocols that incorporate a wide range of energy production (e.g., basal metabolic rate and maximal exercise testing). Accordingly, we built an apparatus that allowed us to manipulate propane burn rates in such a way as to assess the linearity of IC systems. This technical report aimed to assess the accuracy and linearity of three IC systems using our in-house built validation procedure. Approach: A series of trials at different propane burn rates (PBR) (i.e., 200, 300, 400, 500, and 600 mL min-1) were run on three IC systems: Sable, Moxus, and Oxycon Pro. The experimental values for V̇O2 and V̇CO2 measured on the three IC systems were compared to theoretical stoichiometry values. Results: A linear relationship was observed between increasing PBR and measured values for V̇O2and V̇CO2 (99.6%, 99.2%, 94.8% for the Sable, Moxus, and Jaeger IC systems, respectively). In terms of system error, the Jaeger system had significantly (p < 0.001) greater V̇O2(mean difference (M) = -0.057, standard error (SE) = 0.004), and V̇CO2(M = -0.048, SE = 0.002) error compared to either the Sable (V̇O2, M = 0.044, SE = 0.004; V̇CO2, M = 0.024, SE = 0.002) or the Moxus (V̇O2, M = 0.046, SE = 0.004; V̇CO2, M = 0.025, SE = 0.002) IC systems. There were no significant differences between the Sable or Moxus IC systems. Conclusion: The multiple PBR approach permitted the assessment of linearity of IC systems in addition to determining the accuracy of fractions of expired gases.

Changes in muscle activity during the flexion and extension phases of arm cycling as an effect of power output are muscle-specific.

Arm cycling is commonly used in rehabilitation settings for individuals with motor impairments in an attempt to facilitate neural plasticity, potentially leading to enhanced motor function in the affected limb(s). Studies examining the neural control of arm cycling, however, typically cycle using a set cadence and power output. Given the importance of motor output intensity, typically represented by the amplitude of electromyographic (EMG) activity, on neural excitability, surprisingly little is known about how arm muscle activity is modulated using relative workloads. Thus, the objective of this study was to characterize arm muscle activity during arm cycling at different relative workloads. Participants (n = 11) first completed a 10-second maximal arm ergometry sprint to determine peak power output (PPO) followed by 11 randomized trials of 20-second arm cycling bouts ranging from 5-50% of PPO (5% increments) and a standard 25 W workload. All submaximal trials were completed at 60 rpm. Integrated EMG amplitude (iEMG) was assessed from the biceps brachii, brachioradialis, triceps brachii, flexor carpi radialis, extensor carpi radialis and anterior deltoid of the dominant arm. Arm cycling was separated into two phases, flexion and extension, relative to the elbow joint for all comparisons. As expected, iEMG amplitude increased during both phases of cycling for all muscles examined. With the exception of the triceps brachii and extensor carpi radialis, iEMG amplitudes differed between the flexion and extension phases. Finally, there was a linear relationship between iEMG amplitude and the %PPO for all muscles during both elbow flexion and extension.

University-based physical literacy programming for children: Canadian community stakeholders' recommendations.

'Physical literacy' (PL) education-that is, teaching foundational skills, attitudes, behaviors and knowledge about lifelong involvements in physical activities, is an important aspect for health promotion among children. Universities have been playing a critical role by teaching future PL professionals. Additionally, various universities have offered university-based PL programming for neighborhood children as a way of public health promotion service and community engagement. However, this additional role of universities and the ways of promoting the quality of this type of health promotion service programming have not been investigated in the current research literature. Therefore, the purpose of this study was to identify the practicable strategies to enhance the quality of university-based PL programming for children from the perspectives of community stakeholders. Overall, 24 community stakeholders who held professional positions that are related to PL education participated in a 90-min focus group interview. This grounded theory study identified that university-based PL programming for children should be (i) inclusive, (ii) collaborative, (iii) welcoming and (iv) responsive. Practical suggestions and recommendations were also provided. This study has provided empirical knowledge to prioritize aspects for the future actions in planning and implementing university-based PL programming for children and informed for further cross-cultural comparisons amongst the perspectives of participants, university service providers and community stakeholders. The knowledge acquired from this research will also be translated to university service providers who operate similar type of health promotion service programming to the public.

Upper and lower body responses to repeated cyclical sprints.

PURPOSE: To compare the physiological and perceptual responses of the upper and lower body to all-out cyclical sprints with short or long rest periods between sprints. METHODS: Ten recreationally trained males completed four 10 × 10 s sprint protocols in a randomized order: upper body with 30 s and 180 s of rest between sprints, and lower body with 30 s and 180 s of rest between sprints. Additionally, maximum voluntary contractions (MVC) were measured at pre-sprint and post-sprints 5 and 10. Normalized (% of first sprint) peak power, MVC, heart rate (HR) and rating of perceived exertion (RPE) were compared between upper and lower body within the same recovery period, and absolute values (Watts, bpm, RPE scores) were compared within the same body part and between recovery periods. RESULTS: Trivial differences were identified in normalized peak power, HR and RPE values between the upper and lower body in both recovery conditions (<2%, d ≤ 0.1), but MVC forces were better maintained with the upper body (∼9.5%, d = 1.0) in both recovery conditions. Absolute peak power was lower (∼147 Watts, d = 1.3), and HR was higher (∼10 bpm, d = 0.73) in the 30 s compared to 180 s condition in both the upper and lower body whereas RPE scores were similar (<0.6 RPE units, d ≤ 0.1). Despite the reductions in peak power, MVC forces were better maintained in the 30 s condition in both upper (2.5 kg, d = 0.4) and lower (7.5 kg, d = 0.7) body. CONCLUSIONS: Completing a commonly used repeated sprint protocol with the upper and lower body results in comparable normalized physiological and perceptual responses.

Smoking and alcohol consumption patterns among elderly Canadians with mobility disabilities.

BACKGROUND: Mobility disability is a major adverse health outcome associated with aging and an impediment to older adults' well-being and behaviors in social and leisure activities. It has been shown that lifestyle factors, including smoking and alcohol consumption, have been used as coping strategies to deal with the negative impact of disability. The aim of this study was to determine the prevalence of smoking and alcohol consumption among older Canadians with different levels of mobility disabilities and to examine factors associated with these two lifestyle patterns among those with disabilities. METHODS: Secondary data analysis was performed using individuals (n = 6,038) aged 65 years and older from both the 2001 Participation and Activity Limitation Survey and the 2003 Canadian Community Health Survey. Multivariate logistic regressions examined the relationship between disability severity and smoking as well as alcohol consumption while controlling for potential confounding socioeconomic factors. RESULTS: The proportion of current smokers among seniors with less-severe and more-severe mobility disabilities and those in the general population was comparable with 12.55%, 11.57% and 11.93%, respectively. Forty-eight percent of seniors in the general population consumed alcohol regularly, compared to only 12.85% with more-severe mobility disabilities. No significant association was shown between the severity level of mobility disabilities and smoking (odds ratio = 0.90, 95% confidence interval: 0.75, 1.08). However, seniors having more-severe disability were less likely to consume alcohol regularly (odds ratio = 0.76, 95% confidence interval: 0.65, 0.89). Other variables including age, gender, income, living status, and social participation also impacted these lifestyle patterns among the study population. CONCLUSIONS: Smoking and alcohol patterns present different associations with the severity level of mobility disabilities. Compared with the general population, elderly Canadians with mobility disabilities had similar smoking prevalence but differ significantly in terms of alcohol consumption. Results from this research will be relevant to decision makers involved in program planning, health education, and policy development as it pertains to the prevention and management of age-related disability.