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Gabriella Berwig Möller, Maria Júlia Vieira da Cunha Goulart, Bruna Bellincanta Nicoletto, Fernanda Donner Alves and Cláudia Dornelles Schneider

The aim of this study was to conduct a systematic review of the effects of probiotic supplementation on physically active individuals. The participants, interventions, comparisons, outcome and study design inclusion criteria were (a) studies involving healthy adults or older subjects of both sexes who did physical exercise (including athletes and physically active individuals), (b) interventions with probiotics, (c) inclusion of a control group, (d) outcomes not previously defined, and (e) clinical trials and randomized clinical trials, with no language or date restrictions. The search was conducted in the following scientific databases: MEDLINE, Embase, SciELO, Scopus, and Lilacs. Search terms were “Probiotics” OR “Prebiotics” OR “Microbiota” AND “Exercise” OR “Athletes.” The articles were first screened by title and abstract by two independent reviewers and disagreements resolved by a third reviewer. Data were extracted independently by the same two reviewers; results were extracted in duplicate and then compared to avoid errors. A total of 544 articles were retrieved and 24 were included. A total of 1,680 patients were included, most of them being male (n = 1,134, 67.5%), with a mean age of 30.9 ± 6.1 years. Following probiotic supplementation, positive effects have been reported for several outcomes including respiratory tract infection, immunologic markers, and gastrointestinal symptoms in both athletes and nonathletes. However, published studies have distinct protocols and measured outcomes, and some of them have small sample size and failed to prove beneficial effect on probiotic supplementation, leading to inconclusive results for standardized supplementation protocols.

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Iñigo Mujika, Luis Villanueva, Marijke Welvaert and David B. Pyne

Context/Background : International-level swimmers periodize their training to qualify for major championships, then improve further at these events. However, the effects of various factors that could affect performance progressions have not been described systematically. Purpose: To quantify the pattern of change in performance between season best qualifying time and the major championships of the year and to assess the influence of time between performance peaks, ranking at the major events, stroke, event distance, sex, age, and country. Methods: A total of 7832 official competition times recorded at 4 FINA World Championships and 2 Olympic Games between 2011 and 2017 were compared with each swimmer’s season best time prior to the major event of the year. Percentage change in performance was related with the time elapsed between season best and major competition, race event, sex, age, and country using linear mixed modeling. Results: Faster performance (−0.79% [0.67%]; mean [SD]) at the major competition of the year occurred in 38% of all observations vs 62% no change or regression (1.10% [0.88%]). The timing between performance peaks (<34 to >130 d) had little effect on performance progressions (P = .83). Only medal winners (−0.87% [0.91%]), finalists (−0.16% [0.97%]), and US swimmers (−0.44% [1.08%]) progressed between competitions. Stroke, event distance, sex, and age had trivial impact on performance progression. Conclusions: Performance progressions at Olympic Games and World Championships were not determined by timing between performance peaks. Performance progression at a major competition appears necessary to win a medal or make the final, independent of race event, sex, and age.

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Gary J. Farkas, Marika A. Pitot and David R. Gater Jr.

The objective of this systematic review was to examine resting metabolic rate (RMR) measured through indirect calorimetry in adults with chronic spinal cord injury (SCI) and to evaluate the predication equations used for the estimation of RMR in this population. The authors additionally aimed to review the impact of sex and level of injury on RMR. A MEDLINE/PubMed, Google Scholar, Scopus, and Web of Science search was performed for studies published from the database inception to January 2018, identifying 326 articles. On the basis of the inclusion criteria, 22 studies remained for review. All articles that were identified were full-text, English language articles examining adults with chronic SCI who were fasted for a minimum of 8 hr before undergoing RMR through indirect calorimetry for at least 20 min. The measured RMR ranged from 1,256.0 to 1,854.0 kcal/day, whereas the estimated RMR ranged from 1,276.8 to 1,808.0 kcal/day in the chronic SCI population. Seven studies overestimated RMR from 4% to 15%, whereas two studies underestimated RMR from 2% to 17% using prediction equations established for the able-bodied population. Two studies produced SCI-specific equations to estimate RMR. With regard to sex and level of injury, RMR does not differ between individuals with tetraplegia and paraplegia, whereas sex-based differences remain inconclusive, given limited results. These data provide evidence for the use of indirect calorimetry to assess RMR and the need to validate SCI-specific prediction equations in the estimation of RMR.

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Sabrina Skorski, Iñigo Mujika, Laurent Bosquet, Romain Meeusen, Aaron J. Coutts and Tim Meyer

Physiological and psychological demands during training and competition generate fatigue and reduce an athlete’s sport-specific performance capacity. The magnitude of this decrement depends on several characteristics of the exercise stimulus (eg, type, duration, and intensity), as well as on individual characteristics (eg, fitness, profile, and fatigue resistance). As such, the time required to fully recover is proportional to the level of fatigue, and the consequences of exercise-induced fatigue are manifold. Whatever the purpose of the ensuing exercise session (ie, training or competition), it is crucial to understand the importance of optimizing the period between exercise bouts in order to speed up the regenerative processes and facilitate recovery or set the next stimulus at the optimal time point. This implies having a fairly precise understanding of the fatigue mechanisms that contribute to the performance decrement. Failing to respect an athlete’s recovery needs may lead to an excessive accumulation of fatigue and potentially “nonfunctional overreaching” or to maladaptive training. Although research in this area recently increased, considerations regarding the specific time frames for different physiological mechanisms in relation to exercise-induced fatigue are still missing. Furthermore, recommendations on the timing and dosing of recovery based on these time frames are limited. Therefore, the aim of this article is to describe time courses of recovery in relation to the exercise type and on different physiological levels. This summary supports coaches, athletes, and scientists in their decision-making process by considering the relationship of exercise type, physiology, and recovery.

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Rebekah D. Alcock, Gregory C. Shaw, Nicolin Tee, Marijke Welvaert and Louise M. Burke

The urinary excretion of hydroxyproline (Hyp), abundant in collagen protein, may serve as a biomarker of habitual collagen intake, assisting with investigations of current interest in the role of dietary collagen intake in supporting the synthesis of collagenous body tissues. This study investigated the time course of urinary Hyp excretion in “free-living,” healthy, active males following the ingestion of a standardized bolus (20 g) of collagenous (gelatin and a hydrolyzed collagen powder) and dairy (calcium caseinate and hydrolyzed casein) proteins. The excretion of Hyp was assessed over a 24-hr period, separated into three collection periods: 0–6, 6–12, and 12–24 hr. Hyp was elevated for 0–6 hr after the consumption of collagen-containing supplements (gelatin 31.3 ± 8.8 mmol/mol and hydrolyzed collagen 33.7 ± 22.0 mmol/mol vs. baseline: gelatin 2.4 ± 1.7 mmol/mol and hydrolyzed collagen 2.8 ± 1.5 mmol/mol; p < .05), but not for the dairy protein supplements (calcium caseinate 3.4 ± 1.7 mmol/mol and hydrolyzed casein 4.0 ± 3.7 mmol/mol; p > .05). Therefore, urinary Hyp reflects an acute intake of collagenous protein, but is not suitable as a biomarker for quantifying habitual collagen intake, provided through regular dietary practices in “free-living,” healthy, active males.

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Caoimhe Tiernan, Mark Lyons, Tom Comyns, Alan M. Nevill and Giles Warrington

Purpose: Insufficient recovery can lead to a decrease in performance and increase the risk of injury and illness. The aim of this study was to evaluate salivary cortisol as a marker of recovery in elite rugby union players. Method: Over a 10-wk preseason training period, 19 male elite rugby union players provided saliva swabs biweekly (Monday and Friday mornings). Subjective markers of recovery were collected every morning of each training day. Session rating of perceived exertion (sRPE) was taken after every training session, and training load was calculated (sRPE × session duration). Results: Multilevel analysis found no significant association between salivary cortisol and training load or subjective markers of recovery (all P > .05) over the training period. Compared with baseline (wk 1), Monday salivary cortisol significantly increased in wk 4 (14.94 [7.73] ng/mL; P = .04), wk 8 (16.39 [9.53] ng/mL; P = .01), and wk 9 (15.41 [9.82] ng/mL; P = .02), and Friday salivary cortisol significantly increased in wk 5 (14.81 [8.74] ng/mL; P = .04) and wk 10 (15.36 [11.30] ng/mL; P = .03). Conclusions: The significant increase in salivary cortisol on certain Mondays may indicate that players did not physically recover from the previous week of training or match at the weekend. The increased Friday cortisol levels and subjective marker of perceived fatigue indicated increased physiological stress from that week’s training. Regular monitoring of salivary cortisol combined with appropriate planning of training load may allow sufficient recovery to optimize training performance.

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Zhen Zeng, Christoph Centner, Albert Gollhofer and Daniel König

Purpose: Setting the optimal cuff pressure is a crucial part of prescribing blood-flow-restriction training. It is currently recommended to use percentages of each individual’s arterial occlusion pressure, which is most accurately determined by Doppler ultrasound (DU). However, the practicality of this gold-standard method in daily training routine is limited due to high costs. An alternative solution is pulse oximetry (PO). The main purpose of this study was to evaluate validity between PO and DU measurements and to investigate whether sex has a potential influence on these variables. Methods: A total of 94 subjects were enrolled in the study. Participants were positioned in a supine position, and a 12-cm-wide cuff was applied in a counterbalanced order at the most proximal portion of the right upper and lower limbs. The cuff pressure was successively increased until pulse was no longer detected by DU and PO. Results: There were no significant differences between the DU and PO methods when measuring arterial occlusion pressure at the upper limb (P = .308). However, both methods showed considerable disagreement for the lower limbs (P = .001), which was evident in both men (P = .028) and women (P = .008). No sex differences were detected. Conclusions: PO is reasonably accurate to determine arterial occlusion pressure of the upper limbs. For lower limbs, PO does not seem to be a valid instrument when assessing the optimal cuff pressure for blood-flow-restriction interventions compared with DU.

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Blaine E. Arney, Reese Glover, Andrea Fusco, Cristina Cortis, Jos J. de Koning, Teun van Erp, Salvador Jaime, Richard P. Mikat, John P. Porcari and Carl Foster

Purpose: The session rating of perceived exertion (sRPE) is a well-accepted method of monitoring training load in athletes in many different sports. It is based on the category-ratio (0–10) RPE scale (BORG-CR10) developed by Borg. There is no evidence how substitution of the Borg 6–20 RPE scale (BORG-RPE) might influence the sRPE in athletes. Methods: Systematically training, recreational-level athletes from a number of sport disciplines performed 6 randomly ordered, 30-min interval-training sessions, at intensities based on peak power output (PPO) and designed to be easy (50% PPO), moderate (75% PPO), or hard (85% PPO). Ratings of sRPE were obtained 30 min postexercise using either the BORG-CR10 or BORG-RPE and compared for matched exercise conditions. Results: The average percentage of heart-rate reserve was well correlated with sRPE from both BORG-CR10 (r = .76) and BORG-RPE (r = .69). The sRPE ratings from BORG-CR10 and BORG-RPE were very strongly correlated (r = .90) at matched times. Conclusions: Although producing different absolute numbers, sRPE derived from either the BORG-CR10 or BORG-RPE provides essentially interchangeable estimates of perceived exercise training intensity.

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Seihati A. Shiroma, Ursula F. Julio and Emerson Franchini

Purpose: To evaluate criterion validity, reliability, and usefulness of a test to measure maximal aerobic power using judo-specific movements (uchi-komi test [UKtest]). Methods: A total of 12 judokas performed 5 graded exercise tests (GETs) in 4 sessions. In sessions 1 and 2, upper-body (UBtest), lower-body (LBtest), and familiarization UKtest were performed. GETs were randomly performed and separated by at least 48 h. In sessions 3 and 4, test and retest UKtest were performed (7 d apart). For all GETs, peak oxygen consumption (V˙O2peak), maximal heart rate (HRmax), peak blood lactate concentration [Lapeak], maximal aerobic intensity, and rating of perceived exertion (RPE) were determined. Another group of 12 judokas performed the UKtest and 1 confirmation test (20 min after the UKtest) at 105% of maximal aerobic speed until exhaustion to confirm whether maximal responses were achieved. Results: V˙O2peak did not differ (P > .05) between UKtest (46.04 [5.34] mL·kg−1·min−1) and LBtest (44.78 [5.98] mL·kg−1·min−1), but it was higher (P < .05) than UBtest (37.03 [7.16] mL·kg−1·min−1). Total duration (551 [60] s) and [Lapeak] (7.10 [1.76] mmol·L−1) in the UKtest were different (P < .05) from UBtest (416 [47] s, 9.93 [2.15] mmol·L−1, respectively) and LBtest (433 [54] s, 10.29 [2.23] mmol·L−1, respectively). Very large relationships between V˙O2peak in UKtest with UBtest (r = .78; P = .003) and LBtest (r = .87; P < .001) were found. Maximal values were achieved for the UKtest V˙O2peak, HRmax, [Lapeak], RPE, and maximal aerobic speed, with no difference between test and retest (P > .05). In addition, very large intraclass correlation coefficients (ICC) for V˙O2peak (ICC = .86), HRmax (ICC = .90), and maximal aerobic speed (ICC = .81) were found. Conclusion: The UKtest can be considered a valid, reliable, and useful test to measure maximal aerobic power using judo-specific movements.

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David Giles, Joel B. Chidley, Nicola Taylor, Ollie Torr, Josh Hadley, Tom Randall and Simon Fryer

Purpose: To determine if the mathematical model used for the estimation of critical force (CF) and the energy store component W′ are applicable to intermittent isometric muscle actions of the finger flexors of rock climbers, using a multisession test. As a secondary aim, the agreement of estimates of CF and W′ from a single-session test was also determined. The CF was defined as the slope coefficient, and W′ was the intercept of the linear relationship between total “isometric work” (W lim) and time to exhaustion (T lim). Methods: Subjects performed 3 (separated by either 20 min or >24 h) tests to failure using intermittent isometric finger-flexor contractions at 45%, 60%, and 80% of their maximum voluntary contraction. Results: Force plotted against T lim displayed a hyperbolic relationship; correlation coefficients of the parameter estimates from the work–time CF model were consistently very high (R 2 > .94). Climbers’ mean CF was 425.7 (82.8) N (41.0% [6.2%] maximum voluntary contraction) and W′ was 30,882 (11,820) N·s. Good agreement was found between the single-session and multisession protocol for CF (intraclass correlation coefficient [ICC3,1] = .900; 95% confidence interval, .616–.979), but not for W′ (ICC3,1 = .768; 95% confidence interval, .190–.949). Conclusions: The results demonstrated the sensitivity of a simple test for the determination of CF and W′, using equipment readily available in most climbing gyms. Although further work is still necessary, the test of CF described is of value for understanding exercise tolerance and to determine optimal training prescription to monitor improvements in the performance of the finger flexors.