Diagnosing overtraining in athletes using the two-bout exercise protocol

Objective: In this work, whether a two-bout exercise protocol can be used to make an objective, immediately available distinction between non-functional over reaching (NFO) and overtraining syndrome (OTS) was studied. Design: Underperforming athletes who were diagnosed with the suspicion of NFO or OTS were included in the study. Recovery of the athletes was monitored by a sports physician to retrospectively distinguish NFO from OTS. Setting: Sports medicine laboratory Participants: The protocol was started and completed by 10 underperforming athletes. NFO was retrospectively diagnosed in five athletes, and OTS was diagnosed in five athletes. Interventions: A two-bout maximal exercise protocol was used to measure physical performance and stressinduced hormonal reactions. Main outcome measurements: Exercise duration, heart rate and blood lactate concentration were measured at the end of both exercise tests. Venous concentrations cortisol, adrenocorticotrophic hormone (ACTH), prolactin and growth hormone were measured both before and after both exercise tests. Results: Maximal blood lactate concentration was lower in OTS compared with NFO, while resting concentrations of cortisol, ACTH and prolactin concentrations were higher. However, sensitivity of these measures was low. The ACTH and prolactin reactions to the second exercise bout were much higher in NFO athletes compared with OTS and showed the highest sensitivity for making the distinction. Conclusions: NFO might be distinguished from OTS based on ACTH and prolactin reactions to a two-bout exercise protocol. This protocol could be a useful tool for diagnosing NFO and OTS; however, more data should be collected before this test can be used as the gold standard

Isometries of infinite dimensional Hilbert geometries

In this paper we extend two classical results concerning the isometries of strictly convex Hilbert geometries, and the characterisation of the isometry groups of Hilbert geometries on finite dimensional simplices, to infinite dimensions. The proofs rely on a mix of geometric and functional analytic methods

The thermoregulatory and thermal responses of individuals with a spinal cord injury during exercise, acclimation and by using cooling strategies-A systematic review

In individuals with a spinal cord injury thermoregulatory mechanisms are fully or partially interrupted. This could lead to exercise-induced hyperthermia in temperate conditions which can be even more distinct in hot conditions. Hyperthermia has been suggested to impair physiological mechanisms in athletes, which could negatively influence physical performance and subjective well-being or cause mild to severe health issues. The aim was to evaluate the literature on the thermoregulatory and thermal responses of individuals with a spinal cord injury during exercise in temperate and hot conditions taking the effects of cooling techniques and heat acclimation into account. Two electronic databases, PubMed and Web of Science were searched. Studies were eligible if they observed the influence of exercise on various thermoregulatory parameters (e.g., core and skin temperature, sweat rate, thermal sensation) in individuals with a spinal cord injury. In total 32 articles were included of which 26 were of strong, 3 of moderate and 3 of weak quality. Individuals with a high lesion level, especially those with a tetraplegia, reached a higher core and skin temperature with a lower sweat rate. The use of cooling techniques before and during exercise can positively affect the burden of the impaired thermoregulatory system in all individuals with a spinal cord injury. Due to the absence of normal thermoregulatory abilities, individuals with a high-level spinal cord injury need special attention when they are exercising in temperate and hot conditions to prevent them from potential heat related issues. The use of cooling techniques can reduce this risk. [Abstract copyright: Copyright © 2021 Grossmann, Flueck, Perret, Meeusen and Roelands.

Improved 1000-m running performance and pacing strategy with caffeine and placebo effect: a balanced placebo design study

Purpose: To investigate the placebo effect of caffeine on pacing strategy and performance over 1000-m running time-trials using a balanced placebo design. Methods: Eleven well-trained male middle-distance athletes performed seven 1000-m time-trials (one familiarisation, two baseline and four experimental). Experimental trials consisted of the administration of four treatments: informed caffeine/received caffeine (CC), informed caffeine/received placebo (CP), informed placebo/received caffeine (PC), and informed placebo/received placebo (PP). Treatments were randomized. Split times were recorded at 200-, 400-, 600-, 800- and 1000-m and peak heart rate (HRpeak) and rating of perceived exertion (RPE) were recorded at the completion of the trial. Results: Relative to baseline, participants ran faster during CC (d = 0.42) and CP (d = 0.43). These changes were associated with an increased pace during the first half of the trial. No differences were shown in pacing or performance between baseline and the PC (d = 0.21) and open administration of placebo (d = 0.10). No differences were reported between treatments for HRpeak (η2 = 0.084) and RPE (η2 = 0.009). Conclusions: Our results indicate that the effect of believing to have ingested caffeine improved performance to the same magnitude as actually receiving caffeine. These improvements were associated with an increase in pace during the first half of the time-trial

Pacing and Decision Making in Sport and Exercise: The Roles of Perception and Action in the Regulation of Exercise Intensity

In pursuit of optimal performance, athletes and physical exercisers alike have to make decisions about how and when to invest their energy. The process of pacing has been associated with the goal-directed regulation of exercise intensity across an exercise bout. The current review explores divergent views on understanding underlying mechanisms of decision making in pacing. Current pacing literature provides a wide range of aspects that might be involved in the determination of an athlete's pacing strategy, but lacks in explaining how perception and action are coupled in establishing behaviour. In contrast, decision-making literature rooted in the understanding that perception and action are coupled provides refreshing perspectives on explaining the mechanisms that underlie natural interactive behaviour. Contrary to the assumption of behaviour that is managed by a higher-order governor that passively constructs internal representations of the world, an ecological approach is considered. According to this approach, knowledge is rooted in the direct experience of meaningful environmental objects and events in individual environmental processes. To assist a neuropsychological explanation of decision making in exercise regulation, the relevance of the affordance competition hypothesis is explored. By considering pacing as a behavioural expression of continuous decision making, new insights on underlying mechanisms in pacing and optimal performance can be developed. © 2014 Springer International Publishing Switzerland

Impact of a carbohydrate mouth rinse on corticomotor excitability after mental fatigue in healthy college-aged subjects

Mental Fatigue (MF) has been associated with reduced physical performance but the mechanisms underlying this result are unclear. A reduction in excitability of the corticomotor system is a way mental fatigue could negatively impact physical performance. Carbohydrate (CHO) mouth rinse (MR) has been shown to increase corticomotor excitability. The purpose of this study was to determine if CHO MR impacts corticomotor excitability after MF. Fifteen subjects (nine females, six males; age = 23 ± 1 years; height = 171 ± 2 cm; body mass = 69 ± 3 kg; BMI = 23.8 ± 0.7) completed two sessions under different MR conditions (Placebo (PLAC), 6.4% glucose (CHO)) separated by at least 48 h and applied in a double-blinded randomized fashion. Motor-evoked potential (MEP) of the left first dorsal interosseous (FDI) was determined by transcranial magnetic stimulation (TMS) before and after MF. Perceived MF was recorded before and after the MF task using a 100 mm visual analog scale (VAS). MF was greater following PLAC (+30.4 ± 4.0 mm) than CHO (+19.4 ± 3.9 mm) ( = 0.005). MEP was reduced more following PLAC (-16.6 ± 4.4%) than CHO (-3.7 ± 4.7%) ( < 0.001). CHO MR was successful at attenuating the reduction in corticomotor excitability after MF. Carbohydrate mouth rinse may be a valuable tool at combating the negative consequences of mental fatigue

Optimisation of piston compression ring for improved energy efficiency of high performance race engines

The primary function of the piston compression ring is to seal the combustion chamber from the bottom end of the engine. As a result, its conformance to the cylinder liner surface is of prime importance. This close-contact contiguity results in increased friction, making this contact conjunction responsible for a significant proportion of energy losses. The frictional losses can be as much as 2–6% of the expended fuel energy, which is quite significant for such a diminutive contact. Under these conditions, the geometrical profile, the surface topography and the inertial properties of the ring assume significant importance. The paper presents an integrated mixed-hydrodynamic analysis of the compression ring–cylinder liner contact with multi-parameter optimisation, based on the use of a genetic algorithm. The multi-objective functionality includes minimisation of the parasitic energy loss, reduction in the incidence of asperity level interactions as well as minimisation of the ring mass. Both cold running engine conditions and hot running engine conditions in line with the New European Drive Cycle were considered. Hitherto, such an approach has not been reported in the literature

Consensus statement on placebo effects in sports and exercise: the need for conceptual clarity, methodological rigour, and the elucidation of neurobiological mechanisms.

In June 2017 a group of experts in anthropology, biology, kinesiology, neuroscience, physiology, and psychology convened in Canterbury, UK, to address questions relating to the placebo effect in sport and exercise. The event was supported exclusively by Quality Related (QR) funding from the Higher Education Funding Council for England (HEFCE). The funder did not influence the content or conclusions of the group. No competing interests were declared by any delegate. During the meeting and in follow-up correspondence, all delegates agreed the need to communicate the outcomes of the meeting via a brief consensus statement. The two specific aims of this statement are to encourage researchers in sport and exercise science to: 1. Where possible, adopt research methods that more effectively elucidate the role of the brain in mediating the effects of treatments and interventions. 2. Where possible, adopt methods that factor for and/or quantify placebo effects that could explain a percentage of inter-individual variability in response to treatments and interventio

The placebo and nocebo effect on sports performance: A systematic review

This is an accepted manuscript of an article published by Taylor and Francis in European Journal of Sport Science on 20/08/2019, available online: https://www.tandfonline.com/doi/full/10.1080/17461391.2019.1655098 The accepted version of the publication may differ from the final published version.The aim of this review was to determine the magnitude of the placebo and nocebo effect on sport performance. Articles published before March 2019 were located using Medline, Web of Science, PubMed, EBSCO, Science Direct, and Scopus. Studies that examined placebo and nocebo effects of an objective dependent variable on sports performance, which included a control or baseline condition, were included in the analysis. Studies were classified into two categories of ergogenic aids: 1) nutritional and 2) mechanical. Cohen’s d effect sizes were calculated from 32 studies involving 1,513 participants. Small to moderate placebo effects were found for both placebo (d = 0.36) and nocebo (d = 0.37) effects and when separated by nutritional (d = 0.35) and mechanical (d = 0.47) ergogenic aids. The pooled effect size revealed a small to moderate effect size across all studies (d = 0.38). Results suggest that placebo and nocebo effects can exert a small to moderate effect on sports performance