A strong relationship between aerobic fitness and the aerobic response to repeated bouts of high intensity exercise has been established, suggesting that aerobic fitness is important in determining the magnitude of the oxidative response. The elevation of exercise oxygen consumption (VO2) is at least partially responsible for the larger fast component of excess post-exercise oxygen consumption (EPOC) seen in endurance-trained athletes following intense intermittent exercise. Replenishment of phosphocreatine (PCr) has been linked to both fast EPOC and power recovery in repeated efforts. Although 31P magnetic resonance spectroscopy studies appear to support a relationship between endurance training and PCr recovery following both submaximal work and repeated bouts of moderate intensity exercise, PCr resynthesis following single bouts of high intensity effort does not always correlate well with maximal oxygen consumption (VO2max). It appears that intense exercise involving larger muscle mass displays a stronger relationship between VO2max and PCr resynthesis than does intense exercise utilising small muscle mass. A strong relationship between power recovery and endurance fitness, as measured by the percentage VO2max corresponding to a blood lactate concentration of 4 mmol/L, has been demonstrated. The results from most studies examining power recovery and VO2max seem to suggest that endurance training and/or a higher VO2max results in superior power recovery across repeated bouts of high intensity intermittent exercise. Some studies have supported an association between aerobic fitness and lactate removal following high intensity exercise, whereas others have failed to confirm an association. Unfortunately, all studies have relied on measurements of blood lactate to reflect muscle lactate clearance, and different mathematical methods have been used for assessing blood lactate clearance, which may compromise conclusions on lactate removal. In summary, the literature suggests that aerobic fitness enhances recovery from high intensity intermittent exercise through increased aerobic response, improved lactate removal and enhanced PCr regeneration.

Objectives The aim of the study was to determine the short-term impact of a 7-month whole-school physical activity and healthy eating intervention (Action Schools! BC) over the 2007–2008 school year for children and youth in 3 remote First Nations villages in northwestern British Columbia. Study design A pre-experimental pre/post design was conducted with 148 children and youth (77 males, 71 females; age 12.5±2.2 yrs). Methods We evaluated changes in obesity (body mass index [wt/ht 2 ] and waist circumference z-scores: zBMI and zWC), aerobic fitness (20-m shuttle run), physical activity (PA; physical activity questionnaire and accelerometry), healthy eating (dietary recall) and cardiovascular risk (CV risk). Results zBMI remained unchanged while zWC increased from 0.46±1.07 to 0.57±1.04 (p<0.05). No change was detected in PA or CV risk but aerobic fitness increased by 22% (25.4±15.8 to 30.9±20.0 laps; p<0.01). There was an increase in the variety of vegetables consumed (1.10±1.18 to 1.45±1.24; p<0.05) but otherwise no dietary changes were detected. Conclusions While no changes were seen in PA or overall CV risk, zWC increased, zBMI remained stable and aerobic fitness improved during a 7-month intervention. 1

Background Recreation and sport facilities often have unhealthy food environments that may promote unhealthy dietary patterns among children. In response, some Canadian provinces have released voluntary nutrition guidelines for recreation and sport facilities, however implementation has been limited. Organizational capacity building may overcome barriers to implementing guidelines. Eat, Play, Live was a randomized controlled trial embedded within a natural experiment that tested the impact of an 18 month capacity building intervention (CBI) in enhancing implementation of provincial nutrition guidelines, and whether nutrition guidelines were associated with positive changes. Primary outcomes were facility capacity, policy development and food environment quality. Methods Recreation and sport facilities in three guideline provinces were randomized into a guideline + CBI (GL + CBI; n = 17) or a guideline only comparison condition (GL-ONLY; n = 15). Facilities in a province without guidelines constituted a second comparison condition (NO-GL; n = 17). Facility capacity, policy development, and food environment quality (vending and concession) were measured and compared at baseline and follow-up across conditions using repeated measures ANOVA and Chi-square statistics. Healthfulness of vending and concession items was rated as Do Not Sell (least nutritious), Sell Sometimes or Sell Most (most nutritious). Results There were significant time by condition effects, with significant increases in facility capacity (mean ± SD: 30.8 ± 15.6% to 62.3 ± 22.0%; p <  0.01), nutrition policy development (17.6% developed new policies; p = 0.049), overall quality of the concession food environment (14.7 ± 8.4 to 17.5 ± 7.2; p <  0.001), and in the proportion of Sell Most (3.7 ± 4.4% to 11.0 ± 9.0%; p = 0.002) and Sell Sometimes vending snacks (22.4 ± 14.4% to 43.8 ± 15.8%; p <  0.001) in GL + CBI facilities, with a significant decline in Do Not Sell vending snacks (74.0 ± 16.6% to 45.2 ± 20.1%; p <  0.001). Conclusions Significant improvements in facility capacity, policy development and food environment quality occurred in recreation and sport facilities that were exposed to nutrition guidelines and participated in a CBI. Outcomes did not improve in facilities that were only passively or not at all exposed to guidelines. Ongoing capacity building may enhance implementation of voluntary nutrition guidelines, however food environments remained overwhelmingly unhealthy, suggesting additional scope to enhance implementation. Trials registration Clinical trials registration (retrospectively registered): ISRCTN14669997 Jul 3, 2018. Electronic supplementary material The online version of this arti...

This study explored the influence of healthy vending contracts (HVC) on the nutritional quality of vending machine products in 46 Canadian publicly funded recreation and sport facilities. A quasi-experimental comparison design was used to examine the difference in nutritional quality of snack and beverage vending machine products at baseline (December 2015–May 2016) and 18-month follow-up. Staff Surveys assessed facility contract type (HVC or conventional) and vending machine audits identified product nutritional quality. Products were categorized by provincial guidelines as Do Not Sell (DNS), Sell Sometimes (SS) or Sell Most (SM). ANOVA compared categories cross-sectionally (HVC vs conventional) and repeated measures ANOVA compared them longitudinally (HVC-HVC, vs conventional-conventional and conventional-HVC). Approximately one quarter of contracts (24% beverage and 28% snack) had health stipulations at baseline or follow-up. Cross-sectionally, facilities with HVC at any time period had significantly lower percentage DNS (beverage: 56% vs 73%, p = 0.001; snack: 55% vs 85%, p < 0.001), higher SS (beverage: 24% vs 14%, p = 0.003; snack: 35% vs 12%, p < 0.001) and higher SM Products (beverage: 21% vs 13%, p = 0.030; snack: 10% vs 3%, p < 0.003). Longitudinally, facilities with consistent HVC or that changed to HVC showed greater decreases in DNS products over time ( p < 0.050). Although less healthy products were still highly prevalent, facilities with HVC or that changed to HVC had fewer unhealthy products available in their vending machines over time compared to those without HVCs. Healthy vending contracts appear to be an effective change strategy.

In the transition from high school to university, vegetable consumption tends to deteriorate, potentially influencing immediate and longer-term health outcomes. Nudges, manipulation of the environment to influence choice, have emerged as important to behavior change goals. This quasi-experimental pilot study examined the impact of a contextually feasible evidence-informed nudge intervention on food purchasing behavior of older adolescents (1st year students) in a university residence cafeteria in British Columbia, Canada. A co-design process with students and staff identified a student relevant and operationally feasible nudge intervention; a placement nudge, fresh vegetables at the hot food table, combined with a sensory and cognitive nudge, signage encouraging vegetable purchase). Using a 12-week single-case A-B-A-B design, observations of the proportion of vegetables purchased were used to assess intervention efficacy. Data analysis included visual trend inspection, central tendency measures, data overlap, variability and latency. Visual trend inspection showed a positive trend when nudges were in place, which was more apparent with female purchases and during the first intervention (B) phase. However, further analysis showed lack of baseline stability, high variability across phases and overlapping data, limiting efficacy conclusions. Menu choices, staff encouragement, term timing and student finances are other potential influences. Further ‘real world’ nudge research is needed.