Work-rest regimens for work in hot environments: A scoping review.

BACKGROUND: To limit exposures to occupational heat stress, leading occupational health and safety organizations recommend work-rest regimens to prevent core temperature from exceeding 38°C or increasing by ≥1°C. This scoping review aims to map existing knowledge of the effects of work-rest regimens in hot environments and to propose recommendations for future research based on identified gaps. METHODS: We performed a search of 10 databases to retrieve studies focused on work-rest regimens under hot conditions. RESULTS: Forty-nine articles were included, of which 35 were experimental studies. Most studies were conducted in laboratory settings, in North America (71%), on healthy young adults, with 94% of the 642 participants being males. Most studies (66%) employed a protocol duration ≤240 min (222 ± 162 min, range: 37-660) and the time-weighted average wet-bulb globe temperature was 27 ± 4°C (range: 18-34). The work-rest regimens implemented were those proposed by the American Conference of Governmental and Industrial Hygiene (20%), National Institute of Occupational Safety and Health (11%), or the Australian Army (3%). The remaining studies (66%) did not mention how the work-rest regimens were derived. Most studies (89%) focused on physical tasks only. Most studies (94%) reported core temperature, whereas only 22% reported physical and/or mental performance outcomes, respectively. Of the 35 experimental studies included, 77% indicated that core temperature exceeded 38°C. CONCLUSIONS: Although work-rest regimens are widely used, few studies have investigated their physiological effectiveness. These studies were mainly short in duration, involved mostly healthy young males, and rarely considered the effect of work-rest regimens beyond heat strain during physical exertion.

Pain Perception in Contact Sport Athletes: A Scoping Review.

Contact sports athletes are regularly facing acute physical pain in part of their sport; however, the literature investigating pain perception in these athletes remains scarce. This scoping review aimed to explore the literature surrounding pain perception in contact sport athletes and to compile and understand how it is studied. The search strategy consisted of using index terms and keywords in the MEDLINE, EMBASE, SPORTDiscus, Web of Science, PsycINFO, CINAHL and ProQuest Dissertations & Theses Global search engines. Results from 11 studies revealed that a mix of team contact sports and combat sports are studied and are included under the umbrella of contact sports. These athletes are being compared with non-athletes as well as athletes from non-contact sports. The cold pressor test and the pain pressure test are the two predominant methods used to investigate physical pain. This review highlights the need to clearly define sports based on contact levels expected in play to better define the types of pain athletes are facing in their practice. Athletes' level of play as well as years of experience should also be more rigorously reported. While contact sport athletes seem to have a higher level of pain tolerance than both active controls and non-contact athletes, the methods of pain testing are not always justified and appropriate in relation to the pain induced during contact sports. Future experimental studies should use pain testing methods relevant to the pain experienced during contact sports and to better justify the rationale for the choice of these methods.

Effects of tapering on neuromuscular and metabolic fitness in team sports: a systematic review and meta-analysis.

Purpose: To assess the effects of a taper strategy on neuromuscular and metabolic fitness in team sport athletes, through a systematic review and meta-analysis. Method: To be included in this meta-analysis, studies had to involve competitive team sport athletes and a tapering intervention providing details about the procedures used to decrease the training load, as well as competition or field-based criterion performance and all necessary data to calculate effect sizes. Four databases were searched according to these criteria, which led to the identification of 895 potential studies and the subsequent inclusion of 14 articles. Independent variables were training intensity, volume and frequency, as well as the pattern of taper and its duration. The dependent variable was performance obtained in various neuromuscular and metabolic tests. Results: There was limited evidence of a moderate taper-induced improvement in repeated sprint ability (Standardized Mean Difference (SMD) (95%IC;I2) = 0.41 (0.26-0.55;0%)) and moderate evidence of a moderate increase in maximal power (SMD (95%IC;I2) = 0.44 (0.32-0.56;15%)), change of direction speed (SMD (95%IC;I2) = 0.38 (0.15-0.60;28%)) and maximal oxygen uptake (SMD (95%IC;I2) = 0.76 (0.43-1.09;37%)). Conclusion: Tapering is an effective training strategy to improve maximal power, maximal oxygen uptake, repeated sprint ability and change of direction speed in team sports. However, the literature lacks studies using various tapering strategies to compare their effectiveness and make evidence-based recommendations. Future original studies should focus on this major issue.

Use of Active Workstations in Individuals with Overweight or Obesity: A Systematic Review.

OBJECTIVE: This systematic review aims to collect existing literature and summarize the impact of active workstations on the health and work outcomes of participants with overweight or obesity. METHODS: Five databases were examined (until March 2018), and the keywords "desk," "workstation," "work station," and "work stations" were used with any one of the following terms: "active," "bik*," "cycling," "height adjustable," "stepping," "stand up," "standing," "treadmill*," "walk*," "elliptical," "bicycl*," "pedaling," "stability ball," "stability balls," "exercise ball," "exercise balls," "swiss ball," "swiss balls," "sit-to-stand," and "sit stand." RESULTS: Nineteen studies (two with school-aged children) were included in this review. Nine studies used treadmill, three used cycling, one used stepping, and twelve used standing desks. A decrease in sedentary time and an increase in physical activity level and energy expenditure were observed for most of the active workstations. Both the treadmill and the cycle desk improved glycemic control, but the treadmill desk was the only workstation for which improved work performance and help in body-weight management (body fat percentage, body weight, waist and hip circumference) were reported. CONCLUSIONS: Active workstations are a promising solution for decreasing occupational sedentariness. Overall, active workstations have a positive impact on energy expenditure and physical activity in individuals with overweight and obesity.

Strength Training for Middle- and Long-Distance Performance: A Meta-Analysis.

PURPOSE: To assess the net effects of strength training on middle- and long-distance performance through a meta-analysis of the available literature. METHODS: Three databases were searched, from which 28 of 554 potential studies met all inclusion criteria. Standardized mean differences (SMDs) were calculated and weighted by the inverse of variance to calculate an overall effect and its 95% confidence interval (CI). Subgroup analyses were conducted to determine whether the strength-training intensity, duration, and frequency and population performance level, age, sex, and sport were outcomes that might influence the magnitude of the effect. RESULTS: The implementation of a strength-training mesocycle in running, cycling, cross-country skiing, and swimming was associated with moderate improvements in middle- and long-distance performance (net SMD [95%CI] = 0.52 [0.33-0.70]). These results were associated with improvements in the energy cost of locomotion (0.65 [0.32-0.98]), maximal force (0.99 [0.80-1.18]), and maximal power (0.50 [0.34-0.67]). Maximal-force training led to greater improvements than other intensities. Subgroup analyses also revealed that beneficial effects on performance were consistent irrespective of the athletes' level. CONCLUSION: Taken together, these results provide a framework that supports the implementation of strength training in addition to traditional sport-specific training to improve middle- and long-distance performance, mainly through improvements in the energy cost of locomotion, maximal power, and maximal strength.

Exercise-induced ischemic preconditioning and the potential application to cardiac rehabilitation: a systematic review.

Exercise-induced ischemic preconditioning (IPC) can be assessed by the results of the second of sequential exercise tests. Exercise-induced IPC is quantified by using the time to 1-mm ST-segment depression, the rate-pressure product at 1-mm ST-segment depression, the maximal ST-segment depression, and the rate-pressure product at the peak of exercise. Few studies reported whether exercise-induced IPC could be used in cardiovascular rehabilitation. A systematic review of the literature limited to human studies was performed using electronic databases, and the main key words were ischemic preconditioning, warm-up phenomenon, and exercise. After careful review, 38 articles were included in the systematic review. This review summarizes the molecular pathways of IPC and describes the first window of protection induced by sequential exercise tests, as well as the effect of medication on exercise-induced IPC. A section on the exercise protocol, mode of exercise, and intensity provides understanding as to what is needed for clinicians to induce IPC with sequential stress tests. The final section of the review is a discussion of the potential use of exercise-induced IPC in a cardiovascular rehabilitation setting. Even if exercise-induced IPC is a well-documented phenomenon, additional studies are needed in order to more fully understand its use in rehabilitation.

Exercise-induced ischemic preconditioning detected by sequential exercise stress tests: a meta-analysis.

Exercise-induced ischemic preconditioning (IPC) can be assessed with the second exercise stress test during sequential testing. Exercise-induced IPC is defined as the time to 1 mm ST segment depression (STD), the rate-pressure product (RPP) at 1 mm STD, the maximal ST depression and the rate-pressure product at peak exercise. The purpose of this meta-analysis is to validate the parameters used to assess exercise-induced IPC in the scientific community. A literature search was performed using electronic database. The main key words were limited to human studies, which were (a) ischemic preconditioning, (b) warm-up phenomenon, and (c) exercise. Meta-analyses were performed on the study-specific mean difference between the clinical measures obtained in the two consecutive stress tests (second minus first test score). Random effect models were fitted with inverse variance weighting to provide greater weight to studies with larger sample size and more precise estimates. The search resulted in 309 articles of which 34 were included after revision (1053 patients). Results are: (a) time to 1 mm ST segment depression increased by 91 s (95% confidence interval (CI): 75-108), p < 0.001; (b) peak ST depression decreased by -0.38 mm (95% CI: -0.66 to -0.10), p < 0.01; and (c) rate-pressure product at 1 mm STD increased by 1.80 × 10(3)mmHg (95% CI: 1.0-2.0), p < 0.001. This is the first meta-analysis to set clinical parameters to assess the benefit of exercise-induced ischemic preconditioning in sequential stress testing. The results of this first meta-analysis on the sequential stress test confirm what is presented in the literature by independent studies on exercise-induced ischemic preconditioning. From now on, the results could be used in further research to set standardized parameters to assess the phenomenon.

Effects of tapering on performance: a meta-analysis.

PURPOSE: The purpose of this investigation was to assess the effects of alterations in taper components on performance in competitive athletes, through a meta-analysis. METHODS: Six databases were searched using relevant terms and strategies. Criteria for study inclusion were that participants must be competitive athletes, a tapering intervention must be employed providing details about the procedures used to decrease the training load, use of actual competition or field-based criterion performance, and inclusion of all necessary data to calculate effect sizes. Datasets reported in more than one published study were only included once in the present analyses. Twenty-seven of 182 potential studies met these criteria and were included in the analysis. The dependent variable was performance, and the independent variables were the decrease in training intensity, volume, and frequency, as well as the pattern of the taper and its duration. Pre-post taper standardized mean differences in performance were calculated and weighted according to the within-group heterogeneity to develop an overall effect. RESULTS: The optimal strategy to optimize performance is a tapering intervention of 2-wk duration (overall effect = 0.59 +/- 0.33, P < 0.001), where the training volume is exponentially decreased by 41-60% (overall effect = 0.72 +/- 0.36, P < 0.001), without any modification of either training intensity (overall effect = 0.33 +/- 0.14, P < 0.001) or frequency (overall effect = 0.35 +/- 0.17, P < 0.001). CONCLUSION: A 2-wk taper during which training volume is exponentially reduced by 41-60% seems to be the most efficient strategy to maximize performance gains. This meta-analysis provides a framework that can be useful for athletes, coaches, and sport scientists to optimize their tapering strategy.