Short-term heat acclimation prior to a multi-day desert ultra-marathon improves physiological and psychological responses without compromising immune status

Multistage, ultra-endurance events in hot, humid conditions necessitate thermal adaptation, often achieved through short term heat acclimation (STHA), to improve performance by reducing thermoregulatory strain and perceptions of heat stress. This study investigated the physiological, perceptual and immunological responses to STHA prior to the Marathon des Sables. Eight athletes (age 42 ± 4 years and body mass 81.9 ± 15.0 kg) completed 4 days of controlled hyperthermia STHA (60 min·day^?1, 45°C and 30% relative humidity). Pre, during and post sessions, physiological and perceptual measures were recorded. Immunological measures were recorded pre-post sessions 1 and 4. STHA improved thermal comfort (P = 0.02), sensation (P = 0.03) and perceived exertion (P = 0.04). A dissociated relationship between perceptual fatigue and T_re was evident after STHA, with reductions in perceived Physical (P = 0.04) and General (P = 0.04) fatigue. Exercising T_re and HR did not change (P > 0.05) however, sweat rate increased 14% (P = 0.02). No changes were found in white blood cell counts or content (P > 0.05). Four days of STHA facilitates effective perceptual adaptations, without compromising immune status prior to an ultra-endurance race in heat stress. A greater physiological strain is required to confer optimal physiological adaptations.     

Increasing hip and knee flexion during a drop-jump task reduces tibiofemoral shear and compressive forces: implications for ACL injury prevention training

Although most ACL injury prevention programmes encourage greater hip and knee flexion during landing, it remains unknown how this technique influences tibiofemoral joint forces. We examined whether a landing strategy utilising greater hip and knee flexion decreases tibiofemoral anterior shear and compression. Twelve healthy women (25.9 ± 3.5 years) performed a drop-jump task before and after a training session (10–15 min) that emphasised greater hip and knee flexion. Peak tibiofemoral anterior shear and compressive forces were calculated using an electromyography (EMG)-driven knee model that incorporated joint kinematics, EMG and participant-specific muscle volumes and patella tendon orientation measured using magnetic resonance imaging (MRI). Participants demonstrated a decrease in peak anterior tibial shear forces (11.1 ± 3.3 vs. 9.6 ± 2.7 N · kg^?1; P = 0.008) and peak tibiofemoral compressive forces (68.4 ± 7.6 vs. 62.0 ± 5.5 N · kg^?1; P = 0.015) post-training. The decreased peak anterior tibial shear was accompanied by a decrease in the quadriceps anterior shear force, while the decreased peak compressive force was accompanied by decreased ground reaction force and hamstring forces. Our data provide justification for injury prevention programmes that encourage greater hip and knee flexion during landing to reduce tibiofemoral joint loading.     

Circadian rhythm effect on physical tennis performance in trained male players

To determine the effect of circadian rhythm on neuromuscular responses and kinematics related to physical tennis performance, after a standardised warm-up, 13 highly competitive male tennis players were tested twice for serve velocity/accuracy (SVA), countermovement vertical jump (CMJ), isometric handgrip strength (IS), agility T-test (AGIL) and a 10-m sprint (10-m RUN). In a randomised, counter-balance order, tennis players underwent the test battery twice, either in the morning (i.e., AM; 9:00 h) and in the afternoon (i.e., PM; 16:30 h). Paired t-tests were used to analyse differences due to time-of-day in performance variables. Comparison of morning versus afternoon testing revealed that SVA (168.5 ± 6.5 vs. 175.2 ± 6.1 km · h^?1; P = 0.003; effect size [ES] = 1.07), CMJ (32.2 ± 0.9 vs. 33.7 ± 1.1 cm; P = 0.018; ES = 1.46), AGIL (10.14 ± 0.1 vs. 9.91 ± 0.2 s; P = 0.007; ES = 1.23) and 10-m RUN time (1.74 ± 0.1 vs. 1.69 ± 0.1 s; P = 0.021; ES = 0.67) were significantly blunted during the morning testing. However, IS was not affected by time-of-day (P = 0.891). Thus, tennis performance may be reduced when competing in the morning in comparison to early evening. Therefore, coaches and tennis players should focus on schedule the SVA, power, speed and agility training sessions in the afternoon.     

Animalympics,Or How I Became a Sport Scholar

Abstract

While at first unintentional, the author’s path to becoming a sport historian has incorporated her academic trajectory of sport and German/European history along with working in the sport industry. These experiences have benefited both her scholarly research and her teaching and experiential learning opportunities for students in sport management programs.     

A Hole in One: Sport and Environment

Abstract

Sport history is a subfield well positioned to involve and benefit from an interdisciplinary approach to historical actors and spaces. Through the use of personal research and teaching experiences that focuses on the intersection between environmental history and those of sport, this piece explores the value in such an interdisciplinary structure through the examples of researching golf courses as transnational sporting landscapes and of teaching sport and leisure cultures to a diverse student body with high levels of engagement.     

Postpartum Mothers’ Leisure-Time Exercise Behavior is Linked to Positive Emotion During Partner Discussions

Purpose: Marital dissatisfaction and conflict often increase for couples after the birth of a child and are evident in fewer positive family interactions and more negative family interactions. Because exercise is known to increase positive emotions and decrease negative emotions, the current study examined the extent to which higher levels of mothers’ exercise during the postpartum period were related to more positive and fewer negative emotion-expressive behaviors with their infants’ fathers. Method: Mothers’ (N = 46; M = 8 months postpartum) positive and negative expressive behaviors were coded during couples’ discussions of current conflict and positive family experiences. Mothers self-reported their leisure-time exercise behavior. Results: First-time mothers and mothers with higher levels of leisure-time exercise behavior displayed higher levels of positive expressive behaviors during couples’ discussions. Conclusions: Exercise may be associated with increased positive emotion and, in turn, can have great potential to improve family relationships during the postpartum period when marital stress normatively increases, particularly for mothers with more than 1 child. Future longitudinal studies are needed to understand exercise patterns across the postpartum period to identify the most effective timing and optimal level of exercise that lead to more positive expressive behaviors.     

Der Sportwissenschaftler als Unternehmer im Wissensmarkt

Creative ideas are the driving force behind knowledge production, the producers of which are generally domesticated at universities for the purposes of ensuring the methodological credibility of the knowledge produced, in order to minimise the impact of chance in the creation of new knowledge. The status of producers is determined by indicators designed to simulate the demand for knowledge, precipitate a quantitative and qualitative comparison of elements which are not comparable, and establish legitimacy for the means of control used. Furthermore, incentives for competitive sport research and the symbolic recognition of scientists via sport practice play a particular role for knowledge production in sports science. In order to compensate for the practical world’s unwillingness to pay for sports science expertise relevant to competitive sport, the German Federal Institute of Sports Science (BISp) functions as a simulator of demand for knowledge generated by universities, while the Institute for Applied Training Science with its services exclusively available to umbrella organisations limits the range of incentives to produce (competitive) sporting knowledge. Sports scientists are thus faced with a market situation which favours routine research and standard methods, creates legitimacy at a central level, does not necessarily tackle actual issues faced by (competitive) athletes, stimulates demand for monitoring services, and all in all leaves monoculture-driven gaps which could most likely only be avoided by advocating and applying individual scope for action throughout the research ethos.     

The Evolution of a National Research Funding System: Transformative Change Through Layering and Displacement

This article outlines the evolution of a national research funding system over a timespan of more than 40 years and analyzes the development from a rather stable Humboldt-inspired floor funding model to a complex multi-tiered system where new mechanisms continually have been added on top of the system. Based on recent contributions to Historical Institutionalism it is shown how layering and displacement processes gradually have changed the funding system along a number of dimensions and thus how a series of minor adjustments over time has led to a transformation of the system as a whole. The analysis also highlights the remarkable resistance of the traditional academically oriented research council system towards restructuring. Due to this resistance the political system has, however, circumvented the research council system and implemented change through other channels of the funding system. For periods of time these strategies have marginalized the role of the councils.     

Visualising the Interdisciplinary Research Field: The Life Cycle of Economic History in Australia

Interdisciplinary research is frequently viewed as an important component of the research landscape through its innovative ability to integrate knowledge from different areas. However, support for interdisciplinary research is often strategic rhetoric, with policy-makers and universities frequently adopting practices that favour disciplinary performance. We argue that disciplinary and interdisciplinary research are complementary, and we develop a simple framework that demonstrates this for a semi-permanent interdisciplinary research field. We argue that the presence of communicating infrastructures fosters communication and integration between disciplines and the interdisciplinary research field to generate innovative knowledge. We apply this to the experience of economic history in Australia in the second half of the twentieth century to demonstrate the life cycle of a semi-permanent interdisciplinary research field.     

The Aviation Paradox: Why We Can ‘Know’ Jetliners But Not Reactors

Publics and policymakers increasingly have to contend with the risks of complex, safety-critical technologies, such as airframes and reactors. As such, ‘technological risk’ has become an important object of modern governance, with state regulators as core agents, and ‘reliability assessment’ as the most essential metric. The Science and Technology Studies (STS) literature casts doubt on whether or not we should place our faith in these assessments because predictively calculating the ultra-high reliability required of such systems poses seemingly insurmountable epistemological problems. This paper argues that these misgivings are warranted in the nuclear sphere, despite evidence from the aviation sphere suggesting that such calculations can be accurate. It explains why regulatory calculations that predict the reliability of new airframes cannot work in principle, and then it explains why those calculations work in practice. It then builds on this explanation to argue that the means by which engineers manage reliability in aviation is highly domain-specific, and to suggest how a more nuanced understanding of jetliners could inform debates about nuclear energy.