Psychophysiological Responses in Emergency Medical Technician Students during Simulated Work Activities in a Hot Environment.

This study compared physiological responses and cognitive performance during simulated work activities in heat to a thermoneutral condition. First responders perform physically demanding activities in a hot environment which may impose additional burdens on tactical personnel during daily tasks. Ten healthy (8 men and 2 women) participants performed two consecutive simulated work activities with two repetitions of each activity (10 min walking on treadmill and 15 sandbag lifts) under heat and thermoneutral conditions. A Stroop color word test (SCWT) and total mood disturbance (TMD) were obtained at first and second baseline (B1, B2), after a 30-min resting period (B3), and recovery (R1). At the end of the trial, core temperature (Tc), skin temperature (tsk), and mean body temperature (Tb) were higher in the heat condition compared to neutral condition (all p ≤ 0.05), whereas oxygen uptake, heart rate, and mean arterial pressure were not significantly different between conditions. There were no differences in scores of SCWT and TMD between conditions. However, TMD was significantly improved after two successive bouts of exercise compared to B3 (all p ≤ 0.05). This investigation shows that two successive simulated work activities did not induce the detrimental influence on thermoregulatory and cognitive responses. Extended work activities in a hot and humid environment may impose a psychophysiological burden and need to be investigated.

The effects of a loaded rucksack and weighted vest on metabolic cost and stride frequency in female adults.

This study evaluated the metabolic cost and stride frequency during exercise while wearing an evenly distributed weight vest in recreationally fit women. Nine healthy women performed a modified Balke treadmill test until volitional fatigue in one of three conditions; (1) unloaded (2) rucksack and (3) weighted vest. Wearing a weighted vest did not show improvement of V̇O2peak, HRpeak, peak stride frequency or average stride frequency (all p ≥ 0.05). However, total time of exercise was significantly longer in the evenly distributed weight vest condition compared to the rucksack condition (p = 0.024) despite similar V̇O2peak and HRpeak. These results may provide practical information when females in tactical populations are preparing for missions in which heavy loads must be carried. Practitioner summary: This study compared the effects of load carriage mode on metabolic cost and stride frequency during graded exercise in females. The weighted vest showed significantly longer exercise time despite similar V̇O2peak and HRpeak. Development of standardised weight distribution mode may serve as an advantageous strategy for females in tactical settings. Abbreviations: HR: heart rate; V̇O2: oxygen uptake; RPE: rating of perceived exertion; V̇O2peak: peak oxygen uptake; HRpeak: peak heart rate.

Preparticipation Screening Prior to Physical Activity in Community Lifestyle Interventions.

Behavioral lifestyle interventions in the community setting are effective in reducing the risk and burden of chronic diseases. The promotion and implementation of physical activity plays a key role in these community-based lifestyle programs. New guidelines on preparticipation screening for cardiovascular disease prior to physical activity have been released which include substantive modifications. These updated recommendations represent a substantial paradigm shift toward a more liberal approach that results in fewer individuals needing to seek medical clearance before starting a physical activity program. This shift has significant implications for those promoting physical activity within the community setting. The objectives of this commentary are to review the updated recommendations within the context of community-based lifestyle intervention programs such as those currently being offered throughout the United States for the primary purpose of diabetes prevention and to discuss the implications for those providers developing and implementing such programs.

Pulmonary Rehabilitation Exercise Prescription in Chronic Obstructive Pulmonary Disease: Review of Selected Guidelines: AN OFFICIAL STATEMENT FROM THE AMERICAN ASSOCIATION OF CARDIOVASCULAR AND PULMONARY REHABILITATION.

Chronic obstructive pulmonary disease (COPD) is associated with disabling dyspnea, skeletal muscle dysfunction, and significant morbidity and mortality. Current guidelines recommend pulmonary rehabilitation (PR) to improve dyspnea, functional capacity, and quality of life. Translating exercise science into safe and effective exercise training requires interpretation and use of multiple guidelines and recommendations. The purpose of this statement is to summarize for clinicians 3 current chronic obstructive pulmonary disease guidelines for exercise that may be used to develop exercise prescriptions in the PR setting. The 3 guidelines have been published by the American College of Sports Medicine, the American Thoracic Society/European Respiratory Society, and the American Association of Cardiovascular and Pulmonary Rehabilitation. In addition to summarizing these 3 guidelines, this statement describes clinical applications, explores areas of uncertainty, and suggests strategies for providing effective exercise training, given the diversity of guidelines and patient complexity.

Effects of a shoulder injury prevention strength training program on eccentric external rotator muscle strength and glenohumeral joint imbalance in female overhead activity athletes.

Imbalance of the eccentrically-activated external rotator cuff muscles versus the concentrically-activated internal rotator cuff muscles is a primary risk factor for glenohumeral joint injuries in overhead activity athletes. Nonisokinetic dynamometer based strength training studies, however, have focused exclusively on resulting concentric instead of applicable eccentric strength gains of the external rotator cuff muscles. Furthermore, previous strength training studies did not result in a reduction in glenoumeral joint muscle imbalance, thereby suggesting that currently used shoulder strength training programs do not effectively reduce the risk of shoulder injury to the overhead activity athlete. Two collegiate women tennis teams, consisting of 12 women, participated in this study throughout their preseason training. One team (n = 6) participated in a 5-week, 4 times a week, external shoulder rotator muscle strength training program next to their preseason tennis training. The other team (n = 6) participated in a comparable preseason tennis training program, but did not conduct any upper body strength training. Effects of this strength training program were evaluated by comparing pre- and posttraining data of 5 maximal eccentric external immediately followed by concentric internal contractions on a Kin-Com isokinetic dynamometer (Chattecx Corp., Hixson, Tennessee). Overall, the shoulder strength training program significantly increased eccentric external total work without significant effects on concentric internal total work, concentric internal mean peak force, or eccentric external mean peak force. In conclusion, by increasing the eccentric external total exercise capacity without a subsequent increase in the concentric internal total exercise capacity, this strength training program potentially decreases shoulder rotator muscle imbalances and the risk for shoulder injuries to overhead activity athletes.