Specificity and context in post-exercise recovery:it is not a one-size-fits-all approach

The concept of specificity of exercise prescription and training is a longstanding and widely accepted foundation of the exercise sciences. Simply, the principle holds that training adaptations are achieved relative to the stimulus applied. That is, the manipulation of training variables (e.g. intensity or loading, mode, volume and frequency) directly influences the acute training stimulus, and so the long-term adaptive response (Young et al., 2001; Bird et al., 2005). Translating this concept to practice then recommends that exercise be prescribed specific to the desired outcomes, and the more closely this is achieved, the greater the performance gain is likely to be. However, the cardiovascular and metabolic adaptations traditionally associated with long, slow distance training types, similarly achieved using high-intensity training methods (for a review see Gibala et al., 2012), highlights understanding of underlying physiology as paramount for effective training program design. Various other factors including illness, sleep and psychology also impact on the training stimulus (Halson, 2014) and must be managed collectively with appropriate post-exercise recovery to continue performance improvements and reduce overtraining and injury risks (Kenttä and Hassmén, 1998)

Does the technique employed for skin temperature assessment alter outcomes?:a systematic review

Free to read Skin temperature is an important physiological measure that can reflect the presence of illness and injury as well as provide insight into the localised interactions between the body and the environment. The aim of this systematic review was to analyse the agreement between conductive and infrared means of assessing skin temperature which are commonly employed in in clinical, occupational, sports medicine, public health and research settings. Full-text eligibility was determined independently by two reviewers. Studies meeting the following criteria were included in the review: 1) the literature was written in English, 2) participants were human (in vivo), 3) skin surface temperature was assessed at the same site, 4) with at least two commercially available devices employed—one conductive and one infrared—and 5) had skin temperature data reported in the study. A computerised search of four electronic databases, using a combination of 21 keywords, and citation tracking was performed in January 2015. A total of 8,602 were returned. Methodology quality was assessed by 2 authors independently, using the Cochrane risk of bias tool. A total of 16 articles (n = 245) met the inclusion criteria. Devices are classified to be in agreement if they met the clinically meaningful recommendations of mean differences within ±0.5 °C and limits of agreement of ±1.0 °C. Twelve of the included studies found mean differences greater than ±0.5 °C between conductive and infrared devices. In the presence of external stimulus (e.g. exercise and/or heat) five studies foundexacerbated measurement differences between conductive and infrared devices. This is the first review that has attempted to investigate presence of any systemic bias between infrared and conductive measures by collectively evaluating the current evidence base. There was also a consistently high risk of bias across the studies, in terms of sample size, random sequence generation, allocation concealment, blinding and incomplete outcome data. This systematic review questions the suitability of using infrared cameras in stable, resting, laboratory conditions. Furthermore, both infrared cameras and thermometers in the presence of sweat and environmental heat demonstrate poor agreement when compared to conductive devices. These findings have implications for clinical, occupational, public health, sports science and research fields

When do injuries occur in dance? A systematic review and discussion of training load

Sports medicine research suggests that overuse injuries may result from inappropriate training load1-2. In dance research, overuse is estimated to be a factor in 75% of allinjuries3. Training loads for dancers typically involve high repetition of extreme movement. Volume of training ranges from six to eight hours per day during rehearsalperiods and up to ten hours during performance seasons4. Holiday periods, however, can last up to three months5-6. This systematic review identifies studies in ballet andcontemporary dance that have investigated the relationship between injuries and their annual timing (AT) (for example, across a performance season, a semester, or a training or working year). Six electronic databases were searched up to June 3, 2016: PubMed, Embase, CINAHL, SPORTdiscus, Scopus, and the Performing Arts Database. Medical subject headings used in PubMed were “wounds and injuries”,“musculoskeleletal diseases” and “dancing”. Keywords used were injur*, sprain, strain*, “muscul* dis*”, danc* and ballet. Only original data, and cohort studies in balletand/or contemporary dance that report a relationship of injury to AT were included. 1196 abstracts were searched. Reference lists of identified studies were also searched. Two reviewers independently assessed each identified study for risk of bias using the Newcastle-Ottawa Scale (NOS) for Observational Studies7. An analysis of the identified studies was conducted on the relationship of injury and AT across potentially inflective changes in load, such as returning to dance after holiday periods, or transitioning from rehearsal periods to performance seasons, when working hours and cardiovascular demands may increase8-9. In the discussion of training load, findings in sports medicine of a relationship between change in training load and injury, and delay in injury presentation after acute spikes in training load10-11 are highlighted as potentially relevant to dance, particularly as a guide to management oftraining loads. A useful metric, for example, may be to quantify training load as the product of the duration and intensity of training1, which, to the authors’ knowledge hasnot been investigated in relation to injury in dance

Effect of individual environmental heat stress variables on training and recovery in professional team sport

Context: Exercise in hot environments increases body temperature and thermoregulatory strain. However, little is known regarding the magnitude of effect that ambient temperature (Ta), relative humidity (RH), and solar radiation individually have on team-sport athletes. Purpose: To determine the effect of these individual heat-stress variables on team-sport training performance and recovery. Methods: Professional Australian Rules Football players (N = 45) undertook 8-wk preseason training producing a total of 579 outdoor field-based observations with Ta, RH, and solar radiation recorded at every training session. External load (distance covered, in m/min; percentage high-speed running [%HSR] >14.4 km/h) was collected via a global positioning system. Internal load (ratings of perceived exertion and heart rate) and recovery (subjective ratings of well-being and heart-rate variability [root mean square of the successive differences]) were monitored throughout the training period. Mixed-effects linear models analyzed relationships between variables using standardized regression coefficients. Results: Increased solar-radiation exposure was associated with reduced distance covered (−19.7 m/min, P 85% HRmax (3.9%, P a was associated with increased distance covered (19.7 m/min, P < .001) and %HSR (3.5%, P = .005). Conclusions: The authors show the importance of considering the individual factors contributing to thermal load in isolation for team-sport athletes and that solar radiation and RH reduce work capacity during team-sport training and have the potential to slow recovery between sessions.</p

Internal and external cooling methods and their effect on body temperature, thermal perception and dexterity

© 2018 The Authors. Published by PLOS. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1371/journal.pone.0191416© 2018 Maley et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Objective The present study aimed to compare a range of cooling methods possibly utilised by occupational workers, focusing on their effect on body temperature, perception and manual dexterity. Methods Ten male participants completed eight trials involving 30 min of seated rest followed by 30 min of cooling or control of no cooling (CON) (34C, 58% relative humidity). The cooling methods utilised were: ice cooling vest (CV0), phase change cooling vest melting at 14C (CV14), evaporative cooling vest (CVEV), arm immersion in 10C water (AI), portable water-perfused suit (WPS), heliox inhalation (HE) and ice slushy ingestion (SL). Immediately before and after cooling, participants were assessed for fine (Purdue pegboard task) and gross (grip and pinch strength) manual dexterity. Rectal and skin temperature, as well as thermal sensation and comfort, were monitored throughout. Results Compared with CON, SL was the only method to reduce rectal temperature (P = 0.012). All externally applied cooling methods reduced skin temperature (P0.05). Conclusion The present study observed that ice ingestion or ice applied to the skin produced the greatest effect on rectal and skin temperature, respectively. AI should not be utilised if workers require subsequent fine manual dexterity. These results will help inform future studies investigating appropriate pre-cooling methods for the occupational worker.This project is financially supported by the US Government through the Technical Support Working Group within the Combating Terrorism Technical Support Office.Published versio

The reproducibility of 10 and 20km time trial cycling performance in recreational cyclists, runners and team sport athletes

Objectives: This study aimed to determine the reliability of 10 and 20 km cycling time trial (TT) performance on the Velotron Pro in recreational cyclists, runners and intermittent-sprint based team sport athletes, with and without a familiarisation. Design: Thirty-one male, recreationally active athletes completed four 10 or 20 km cycling TTs on different days. Methods: During cycling, power output, speed and cadence were recorded at 23 Hz, and heart rate and rating of perceived exertion (RPE) were recorded every km. Multiple statistical methods were used to ensure a comprehensive assessment of reliability. Intraclass correlations, standard error of the measurement, minimum difference required for a worthwhile change and coefficient of variation were determined for completion time and mean trial variables (power output, speed, cadence, heart rate, RPE, session RPE). Results: A meaningful change in performance for cyclists, runners, team sport athletes would be represented by 7.5, 3.6 and 12.9% improvement for 10 km and a 4.9, 4.0 and 5.6% for 20 km completion time. After a familiarisation, a 4.0, 3.7 and 6.4% improvement for 10 km and a 4.1, 3.0 and 4.4% would be required for 20 km. Conclusions: Data from this study suggest not all athletic subgroups require a familiarisation to produce substantially reliable 10 and 20 km cycling performance. However, a familiarisation considerably improves the reliability of pacing strategy adopted by recreational runners and team sport athletes across these distances

Is recovery driven by central or peripheral factors? A role for the brain in recovery following intermittent-sprint exercise

Prolonged intermittent-sprint exercise (i.e., team sports) induce disturbances in skeletal muscle structure and function that are associated with reduced contractile function, a cascade of inflammatory responses, perceptual soreness, and a delayed return to optimal physical performance. In this context, recovery from exercise-induced fatigue is traditionally treated from a peripheral viewpoint, with the regeneration of muscle physiology and other peripheral factors the target of recovery strategies. The direction of this research narrative on post-exercise recovery differs to the increasing emphasis on the complex interaction between both central and peripheral factors regulating exercise intensity during exercise performance. Given the role of the central nervous system (CNS) in motor-unit recruitment during exercise, it too may have an integral role in post-exercise recovery. Indeed, this hypothesis is indirectly supported by an apparent disconnect in time-course changes in physiological and biochemical markers resultant from exercise and the ensuing recovery of exercise performance. Equally, improvements in perceptual recovery, even withstanding the physiological state of recovery, may interact with both feed-forward/feed-back mechanisms to influence subsequent efforts. Considering the research interest afforded to recovery methodologies designed to hasten the return of homeostasis within the muscle, the limited focus on contributors to post-exercise recovery from CNS origins is somewhat surprising. Based on this context, the current review aims to outline the potential contributions of the brain to performance recovery after strenuous exercise

The specificity of Rugby Union training sessions in preparation for match demands

<b>Purpose</b>\ud \ud Investigations into the specificity of rugby union training practices in preparation for competitive demands has predominantly focussed on physical and physiological demands. The evaluation of the contextual variance in perceptual strain or skill requirements between training and matches in rugby union is unclear, yet holistic understanding may assist to optimise training design. This study evaluated the specificity of physical, physiological, perceptual and skill demands of training sessions compared with competitive match-play in pre-professional, elite club rugby union. \ud \ud <b>Methods</b>\ud \ud Global positioning system (GPS) devices, video capture, heart rate (HR), and session ratings of perceived exertion (sRPE) were used to assess movement patterns, skill completions, physiologic, and perceptual responses, respectively. Data were collected across a season (training sessions n=29; matches n=14). Participants (n=32) were grouped in playing positions as: outside backs, centres, halves, loose forwards, lock forwards, and front row forwards. \ud \ud <b>Results</b>\ud \ud Greater total distance, low-intensity activity, maximal speed and metres per min were apparent in matches compared to training in all positions (P<0.02; d>0.90). Similarly, match HR, and sRPE responses were higher than those recorded in training (P<0.05; d>0.8). Key skill completions for forwards (i.e., scrums, rucks and lineouts) and backs (i.e., kicks) were greater under match conditions than in training (P<0.001; d>1.50). \ud \ud <b>Conclusion</b>\ud \ud Considerable disparities exist between the perceptual, physiological, and key skill demands of competitive matches versus training sessions in pre-professional rugby union players. Practitioners should consider the specificity of training tasks for pre-professional rugby players to ensure the best preparation for match demands