Proper hydration for distance running : identifying individual fluid needs

Un guide sur les besoins d'une hydratation adéquate ainsi que sur les dangers d'une hydratation insuffisante ou excessive

Dehydration Reduces Posterior Leg and Trunk Flexibility and Increases Stiffness in Male Collegiate Age Runners

Dehydration reduces flexibility and increases stiffness in male collegiate age runners. Dehydration has been shown to negatively affect collagen in vitro; however the literature lacks works exploring the in vivo effects of dehydration on collagenous tissue. This study addresses this gap in the literature, by exploring the effects of dehydration on the muscles and connective tissues of the posterior leg. It was hypothesized that when dehydrated, the collagen within these tissues would become stiffer, decreasing flexibility and increasing stiffness. A cross-over cohort design was conducted to evaluate nineteen male collegiate runners. Each subject attended three sessions: baseline, dehydration and euhydration. The order of testing was randomly assigned and the PI was blinded throughout. Mean sit and reach (MSnR), mean terminal straight leg raise (MTSLR) and mean posterior leg stiffness (MPLS) scores for each testing condition were analyzed using a repeated measures ANOVA. Dehydrated, subjects demonstrated statistically significant decreases in MSnR scores, p\u3c0.001, d=0.469 (MSnR dehydrated 26.83 ± 7.53 cm and MSnR euhydrated 30.36 ± 7.53 cm) and MTSLR, p\u3c0.001, d=1.068 (MTSLR dehydrated 51.38 ± 9.39 and MTSLR euhydrated 60.58 ± 7.74), with a concurrent increase in MPLS, p=0.005, d=1.023 (MPLS dehydrated 0.899 ± 0.357 and MPLS euhydrated 0.508 ± 0.409), as compared to when they were euhydrated. The large effect size for MPLS and MTSLR and moderate for MSnR indicates that when dehydrated subjects became stiffer and has less flexibility as compared to when they are euhydrated. These changes may impede performance and increase the risk of injury in dehydrated individuals

Effect of Cueing on Learning Transfer Among Pre-professional Undergraduate Healthcare Students Engaged in a Case-based Analogical Reasoning Exercise

To examine the extent of transfer of cued versus non-cued pre- professional healthcare undergraduates engaged in a case-based analogical reasoning exercise. Independent t-test analysis and effect size was calculated to assess transfer between cued and non-cued participants (N = 192). Cued participants (n = 98, M = 2.30, SD = .89) demonstrated significantly more transfer (t (175.91) = 2.65; p = .009; CI95 = (.10, 0.68); d = .39) than non-cued participants (n = 94, M = 1.9, SD = 1.14). Learning transfer improves among pre- professional undergraduates when cued during a case-based analogical reasoning experience

Fluid Needs for Training, Competition, and Recovery in Track-and-Field Athletes

The 2019 International Amateur Athletics Federation Track-and-Field World Championships will take place in Qatar in the Middle East. The 2020 Summer Olympics will take place in Tokyo, Japan. It is quite likely that these events may set the record for hottest competitions in the recorded history of both the Track-and-Field World Championships and Olympic Games. Given the extreme heat in which track-and-field athletes will need to train and compete for these games, the importance of hydration is amplified more than in previous years. The diverse nature of track-and-field events, training programs, and individuality of athletes taking part inevitably means that fluid needs will be highly variable. Track-and-field events can be classified as low, moderate, or high risk for dehydration based on typical training and competition scenarios, fluid availability, and anticipated sweat losses. This paper reviews the risks of dehydration and potential consequences to performance in track-and-field events. The authors also discuss strategies for mitigating the risk of dehydration

Athletic Administrators Report of Emergency Action Plan Adoption in Secondary School Athletics: The Influence of Athletic Training Services

This study describes the emergency action plan (EAP) adoption in secondary school athletics reported by athletic administrators in the United States. Utilizing best-practice criteria, a questionnaire assessed athletic administrators’ knowledge and adoption of an EAP in their athletics program. A majority of athletic administrators reported having an EAP; however, the EAP often lacked the necessary components to be compliant with best-practice guidelines. Further, access to an athletic trainer was associated with increased EAP adoption and adopting a venue specific EAP. Athletic administrators should utilize these data to facilitate improved policy adoption and management of athletics programs

Carbon Fiber Insoles Enhance Perception of Performance Despite Variable Objective Outcomes: Specific to the Moderately Active Individual

International Journal of Exercise Science 16(4): 885-897, 2023. Carbon fiber insoles (CFIs) may benefit performance in elite athletes, however, their use in moderately active individuals has been adopted without evidence supporting such enhancements in this population. Fifteen male subjects performed vertical jump (VJ) and repeat treadmill sprint tests before and after a VO2peak while wearing 1) CFIs and 2) control insoles (CON). Subjects completed a subjective survey regarding their perceived performance abilities for both conditions. There were no significant differences between CFIs and CON in VJ height, sprint distance, heart rate following sprints; and rate of oxygen consumption, perceived fatigue, and perceived exertion at 85% of maximal speed (p \u3e 0.05) during the VO2peak. At maximal speed, although there was no difference between conditions in peak rate of oxygen consumption (95%CI [-4.85, 0.21]) and respiratory exchange ratio (95%CI [-0.01, 0.03]), CFIs resulted in a reduced level of perceived fatigue (95%CI [-1, 0]) and perceived exertion (95%CI [-2, 0]) compared to CON. Subjects subjectively reported increased feelings of “propulsion or explosiveness” (p = 0.026) and being able to “perform better while jumping” (p = 0.029) while wearing CFIs. Heightened perceptions of performance enhancements when wearing CFIs indicate, in the moderately active, perceptual benefits could be more influential for determining CFI use

The Prevalence of Secondary School Sport Safety Policies within State Athletic Associations and Legislation

Purpose: The location of secondary school health and safety policies impacts how they are implemented by the sports medicine team and stakeholders. Yet, a comprehensive list of each state’s policy locations has not been established. The purpose of this study was to describe where secondary school health and safety policies were located at the state level within the United States. Method: Emergency related health and safety policies were designated as either being located in the state high school athletics association (SHSAA), state legislation (LEGIS), or in both SHSAA and LEGIS (BOTH). Designation was determined by two researchers who independently reviewed each individual policy. Frequencies were tabulated for the leading causes of catastrophic injury (exertional heat stroke (EHS), traumatic head injuries (THI), sudden cardiac arrest (SCA), and emergency preparedness (EP)) for the distribution of policies emanating from SHSSA, LEGIS or BOTH. Prevalence ratios (PRs) with 95% confidence intervals (CIs) were calculated between the policies categories and location. Results: Most (99.35%) EHS and EP (83.02%) policies were found in SHSAA. Whereas the majority (79.70%) of SCA policies were found in LEGIS. Traumatic head injuries were most frequently observed in SHSAA, however, had the greatest distribution across all three categories (SHSAA=45.31%, LEGIS=25.52%, BOTH = 29.16%). The category that most frequently found policies in BOTH was THI (THI= 29.16%, all others =2.25%; PR=12.96; 95% CI=7.81, 21.53). Conclusions: Emergency related health and safety policies for secondary school sports are commonly found in SHSAA. TBI and SCA are also found in LEGIS. This demonstrates great variability of policy locations

The Precaution Adoption Process Model in Describing Emergency Action Plan Adoption

Purpose: The purpose of this study was to identify the ability of the Precaution Adoption Process Model (PAPM) to classify athletic trainers (ATs) and athletic directors (ADs) readiness to act with regards to adopting an emergency action plan (EAP), and describe factors influencing PAPM stages. Method: We used a cross-sectional questionnaire design to evaluate readiness to act for developing an EAP among ATs and ADs working in United States high schools. The PAPM is a participant-driven model to identify someone’s readiness to act or change and has seven stages: Unaware, Unengaged, Undecided, Decided not to Act, Decided to Act, Acting and Maintaining. Prevalence ratios (PRs) with 95% confidence intervals (95% CI) were calculated. Results: A majority of ATs and ADs reported maintaining an EAP in their secondary school (AT “Maintaining” = 84.4%, AD “Maintaining” = 68.7%). ADs were more likely to be staged as “Decided not to Act” (PR=0.14, 95% CI= 0.05, 0.41) for the development of an EAP compared to ATs. ATs were more likely to be staged as “Maintaining” (PR=1.23, 95% CI = 1.16, 1.30) for the development of an EAP compared to ADs. Conclusions: The PAPM appears to be able to classify AT and AD readiness to act with adoption of an EAP. However, statistical modeling struggles to identify predictors for the various stages. Future research should aim to use the PAPM stages in the development of tailored interventions

The Effects of Heat Acclimatization, Heat Acclimation, and Intermittent Heat Training on Maximal Oxygen Uptake

Maximal oxygen uptake (VO2max) is an important determinant of endurance performance. Heat acclimation/acclimatization (HA/HAz) strategies elicit improvements in endurance performance. When heat exposure is reduced, intermittent heat training (IHT) is potentially beneficial to alleviate HA/HAz adaptation decay, however corresponding VO2max responses are unknown. PURPOSE: To determine the effects of HA/HAz and IHT on VO2max in endurance runners and identify how long VO2max adaptations remain following removal of repeated heat exposure. METHODS: Twenty-seven male endurance runners (mean ± SD; age, 36 ± 12 years; body mass, 73.03 ± 8.97 kg; height, 178.81 ± 6.39 cm; VO2max, 57.48 ± 7.03 ml.kg-1.min-1) completed VO2max and exercise testing at five time points; baseline, pre-HA, post-HA, week 4 of IHT (IHT4), and week 8 of IHT (IHT8). Exercise testing and HA environmental conditions were the same (ambient temperature, 35.42 ± 1.06°C; relative humidity, 46.35 ± 2.48%). Following baseline testing, participants completed HAz, proceeded by 5 days of HA involving exercise to induce hyperthermia (38.50 - 39.50°C) for 60 minutes. Participants were then randomly assigned to one of three IHT groups: once weekly (n = 9), twice weekly (n = 10), or no IHT (n = 8). Differences in VO2max and maximal heart rate at VO2max (HRmax) for baseline, pre-HA, post-HA, IHT4, and IHT8 were analyzed using repeated-measures ANOVAs with Bonferroni corrections post-hoc. RESULTS: No significant VO2max differences were observed between baseline (57.92 ± 6.82 ml.kg-1.min-1), pre-HA (59.65 ± 8.24 ml.kg-1.min-1), and post-HA (59.49 ± 7.18 ml.kg-1.min-1, p = 0.36). No significant group or time effects were identified for VO2max at post-HA, IHT4, and IHT8 (p = 0.67). However, significant HRmax differences were observed between baseline (180 ± 11 beats.min-1), pre-HA (177 ± 10 beats.min-1), and post-HA tests (175 ± 10 beats.min-1, p = 0.01). No significant group or time HRmax differences were shown for post-HA, IHT4, and IHT8 (p = 0.59). CONCLUSION: No changes in VO2max were identified among endurance runners following HA/HAz, potentially due to participants’ high aerobic fitness levels. As IHT maintained VO2max following 8 weeks without repeated heat exposure, it is potentially a beneficial strategy to minimize VO2max adaptation decay in endurance athletes

The Effects of Energy Intake on Upper Respiratory Symptoms in Ultra-Endurance Triathletes

Background: It is unclear whether energy intake can impact the incidence of upper respiratory symptoms (URS). The purpose of this study was to examine if there are differences in energy intake between symptomatic (SYM) and asymptomatic (ASYM) groups of URS in Ironman-triathletes. Methods: Thirty-three subjects competing in the Lake Placid Ironman-triathlon (mean±SD; age,37±8y; height,178±8cm; mass,76.3±10.4kg; body fat,10.8±3.8%) were randomized into either the control (CON) or intervention (INT). INT consumed 4-commercial recovery drinks, two immediately post-race and two 3-hours post-race. Calorie and macronutrient intake were recorded pre-, during, and post-race. Subjects completed the Wisconsin URS Survey to assess URS over the next two weeks. Two analyses were done by comparing results between CON and INT, and when subjects were classified as either asymptomatic (ASYM=20) or symptomatic (SYM=13). Results: There were no differences in energy intake (p\u3e0.05) and URS (INT,32±38; CON,16±23; p=0.155). However, on the race day, SYM (9,044±2,598kcal) consumed less energy intake than ASYM (10,991±2497kcal) (p=0.044). Also, SYM consumed less energy the day before the race (p=0.031) and post-race (p=0.008). ASYM consumed greater carbohydrate the day before the race (p=0.032), fat the day of the race (p=0.006), carbohydrate post-race (p=0.08) and fat post-race (p=0.002). Conclusions: Overall energy intake was similar between CON and INT. However, when subjects were differentiated by URS, SYM consumed less calories the day before and day of the race versus ASYM