Sports Sciences Commons^™

Effectiveness Of Short-Term Heat Acclimation On Intermittent Sprint Performance In The Heat With Moderately Trained Males, Andrew T. Garrett, Matt Birkett, Damien O. Gleadall-Siddall, Rachel Burke, James Bray, Fiona Nation

Journal of Human Performance in Extreme Environments

Purpose: Effectiveness of short-term heat acclimation (STHA), over 5-days (permissive dehydration), on intermittent heat stress test (HST) with males. Methods: Ten, moderately-trained, males (mean [SD]; age 25.6 [8.9] y; stature 180.7 [5.6] cm; body mass 83.2 [10.8] kg; and 45.3 [6.5] mL^.kg^-1.min^-1) participated. The HST was 9 x 5min (45-min) of intermittent exercise based on professional soccer players. One week apart, HST1 vs HST (11.0°C; 50%RH), as a reliability trial and HST3 in 31.0°C; 50%RH were completed. Then 90 min dehydration, STHA (no fluid intake), for 5 consecutive days (39.5^oC; 60%RH), using …

Errors Of Measurement For Blood Parameters And Physiological And Performance Measures After The Decay Of Short-Term Heat Acclimation, Andrew T. Garrett, Nancy J. Rehrer, Mark J. Patterson, Andrew J. Simpson, James D. Cotter

Journal of Human Performance in Extreme Environments

Introduction: It is important to determine the accuracy of measurements relative to potential treatment effects, with time intervals between tests. Purpose: The aim of this study was to assess the error of measurement for blood parameters, physiological, and performance measures after the decay of short-term heat acclimation. Methods: Ten trained males (Mean±SD: age 28±7 y; body mass 74.6±4.4 kg; 4.26±0.37 L^.min^-1; peak power output (PPO) 329±42 W) completed an exercising heat stress test (HST) at baseline, 2^nd day after acclimation and then during decay at 1, 2, 3 and 5-6 wks. CoV (95% CI), SE …

Sources Of Nutrition Information In Recreational Ultra-Marathon Runners: A Mixed Methods Analysis, Sara E. Mahoney, Thomas R. Wójcicki, Andrew J. Carnes

Journal of Human Performance in Extreme Environments

Ultra-marathon events (i.e., .42.2-km) continue to grow in popularity; however, little is known regarding the sources of nutrition information which inform their beliefs and habits. The objective of this study was to characterize the acquisition of sport-specific nutrition information among ultra-endurance athletes using a mixed methods design. Qualitative data were collected through focus groups and analyzed using thematic analysis. Three primary higher order themes were identified: Optimal Diet for Ultra-Endurance Athletes, Common Sources of Information, and Barriers to Scientific Information. Then, a self-report inventory (Sources of Nutrition Information-SONI questionnaire) was developed to assess common sources of nutrition information and characterize …

Higher Muscle Tissue Oxygenation When Exposed To Hypobaric Hypoxia Than Normobaric Hypoxia, Christina N. Angeli, Robert J. Shute, Dustin R. Slivka

Journal of Human Performance in Extreme Environments

There has been recent debate on the potential difference in physiological response between exposure to simulated altitude (normobaric hypoxia) and terrestrial altitude (hypobaric hypoxia). Purpose: To determine the difference in the physiological response to normobaric and hypobaric hypoxia during exercise. Methods: Eight recreationally active subjects (27 ± 5 y old, 73.1 ± 7.4 kg body weight, 170.6 ± 6.7 cm height, and 19.3 ± 9.2 % body fat) completed incremental cycling exercise to volitional fatigue in three separate environments: normobaric normoxia (NN; 350 m), normobaric hypoxia (NH; simulated 3094 m), and hypobaric hypoxia (HH; 3094 m). Heart rate, blood oxygen …

Technical Freediving: An Emerging Breath-Hold Diving Technique, Derek Covington, Robert H. Lee, Steven Toffel, Alberto Bursian, Kirk Krack, Chris Giordano

Journal of Human Performance in Extreme Environments

Technical freediving can be defined as freediving augmented by the use of oxygen-enriched gases or oxygen before, during, or after a freedive. As a result of these techniques, breath-hold divers can visit and enjoy underwater wrecks, reefs, and other diving locations previously located at depths unreachable to apnea divers. By pre-breathing oxygen-enriched gases in conjunction with hyperventilation—which decreases the partial pressure of carbon dioxide (PCO2)—the technical freediver now has additional oxygen to facilitate aerobic respiration during the dive. In addition, pre-breathing oxygen decreases tissue nitrogen tensions, which limits inert gas loading and decreases the risk of decompression sickness (DCS). Finally, …

Habitual Heat Exposure And Acclimatization Associated With Athletic Performance In The Multistage Marathon Des Sables, Leonidas G. Ioannou, Lydia Tsoutsoubi, Lars Nybo, Georgios I. Tsianos, Andreas D. Flouris

Journal of Human Performance in Extreme Environments

Introduction

The aim of this study was to investigate the impact of heat acclimatization on athletic performance during the 7-day Marathon des Sables (MdS) which takes place in the Sahara Desert.

Methods

Anonymous data for nationality and average running speed (km/h) of all runners who ran the MdS during the period 2000–2015 were collected from the official website of the race and other related websites. Average maximum temperature for each runner’s country during the month preceding the MdS was collected from www.weatherbase.com. Athletes were divided into two Torigin groups as follows: 25 to 15°C (i.e., cold countries) and 15 to …

Effects Of Body Armor And Load Carriage On Lower Limb Joint Movement, Huiju Park, Donna Branson, Adriana Petrova, Semra Peksoz, Carla Goad, Aric J. Warren, Bert Jacobson, Panagiotis Kamenidis

Journal of Human Performance in Extreme Environments

This study investigated the impact of body armor weight and load magnitude and distribution on the lower extremities during walking. Range of motion (ROM) was assessed while seven healthy, male, right-handed, military university students walked while wearing seven different garments of varying weights (0.06 kg, 9 kg, 18 kg, and 27 kg) and load distributions. Decreased pelvic rotation found with an increase in weight implies decreased mobility by restricting the leg’s swing to propel the body forward. Increased ROM for pelvic tilt found with increased weight results from increased forward inclination suggesting an increased possibility for fatigue and musculoskeletal pain …