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1.
The effect of foot orthoses and insoles on running economy and performance in distance runners: A systematic review and meta-analysis.
Crago, D, Bishop, C, Arnold, JB
Journal of sports sciences. 2019;(22):2613-2624
Abstract
Foot orthoses and insoles are prescribed to runners, however their impact on running economy and performance is uncertain. The aim of this systematic review and meta-analysis was to determine the effect of foot orthoses and insoles on running economy and performance in distance runners. Seven electronic databases were searched from inception until June 2018. Eligible studies investigated the effect of foot orthoses or insoles on running economy (using indirect calorimetry) or running performance. Standardised mean differences (SMDs) were computed and meta-analyses were conducted using random effects models. Methodological quality was assessed using the Quality Index. Nine studies met the criteria and were included: five studies investigated the effect of foot orthoses on running economy and four investigated insoles. Foot orthoses were associated with small negative effects on running economy compared to no orthoses (SMD 0.42 [95% CI 0.17,0.72] p = 0.007). Shock absorbing insoles were also associated with negative effects on running economy, but an imprecise estimate (SMD 0.26 [95% CI -0.33,0.84] p = 0.83). Quality Index scores ranged from 4 to 15 out of 17. Foot orthoses and shock absorbing insoles may adversely affect running economy in distance runners. Future research should consider their potential effects on running performance.
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2.
The effect of 1,3-butanediol and carbohydrate supplementation on running performance.
Scott, BE, Laursen, PB, James, LJ, Boxer, B, Chandler, Z, Lam, E, Gascoyne, T, Messenger, J, Mears, SA
Journal of science and medicine in sport. 2019;(6):702-706
Abstract
OBJECTIVES Ingested ketogenic agents offer the potential to enhance endurance performance via the provision of an alternative exogenous, metabolically efficient, glycogen-sparing fuel (i.e. ketone bodies). This study aimed to assess the impact of combined carbohydrate and 1,3-butanediol (CHO-BD) supplementation on endurance performance, blood beta-hydroxybutyrate (βHB) concentration and glycolytic activity, in comparison to carbohydrate supplementation alone (CHO). DESIGN Eleven male runners (age 38±12years, mass 67.3±6.5kg, height 174.5±5.0cm, [Formula: see text] 64.2±5.0ml⋅kg-1⋅min-1) performed two experimental trials in a randomised crossover design. METHODS Each trial consisted of 60min of submaximal running, followed by a 5km running time-trial (TT), and was performed following the ingestion of an energy matched ∼650ml drink (CHO-BD or CHO). RESULTS There was no difference in TT completion time between the trials (CHO: 1265±93, CHO-BD: 1261±96s; p=0.723). However, blood βHB concentration in the CHO-BD trial was at least double that of the CHO trial at all time points following supplementation (p<0.05). While blood lactate concentration was lower in the CHO-BD versus CHO trial after 30min submaximal exercise (CHO-BD: 1.46±0.67mmol⋅L-1, CHO: 1.77±0.46mmol⋅L-1, p=0.040), it was similar at other time points. Blood glucose concentrations were higher post-TT in the CHO-BD trial (CHO-BD: 5.83±1.02mmol⋅L-1, CHO: 5.26±0.95mmol⋅L-1, p=0.015). CONCLUSIONS An energy matched CHO-BD supplementation drink raised βHB concentration and acutely lowered blood lactate concentration, without enhancing 5km TT running performance.
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3.
Contemporary Nutrition Strategies to Optimize Performance in Distance Runners and Race Walkers.
Burke, LM, Jeukendrup, AE, Jones, AM, Mooses, M
International journal of sport nutrition and exercise metabolism. 2019;(2):117-129
Abstract
Distance events in Athletics include cross country, 10,000-m track race, half-marathon and marathon road races, and 20- and 50-km race walking events over different terrain and environmental conditions. Race times for elite performers span ∼26 min to >4 hr, with key factors for success being a high aerobic power, the ability to exercise at a large fraction of this power, and high running/walking economy. Nutrition-related contributors include body mass and anthropometry, capacity to use fuels, particularly carbohydrate (CHO) to produce adenosine triphosphate economically over the duration of the event, and maintenance of reasonable hydration status in the face of sweat losses induced by exercise intensity and the environment. Race nutrition strategies include CHO-rich eating in the hours per days prior to the event to store glycogen in amounts sufficient for event fuel needs, and in some cases, in-race consumption of CHO and fluid to offset event losses. Beneficial CHO intakes range from small amounts, including mouth rinsing, in the case of shorter events to high rates of intake (75-90 g/hr) in the longest races. A personalized and practiced race nutrition plan should balance the benefits of fluid and CHO consumed within practical opportunities, against the time, cost, and risk of gut discomfort. In hot environments, prerace hyperhydration or cooling strategies may provide a small but useful offset to the accrued thermal challenge and fluid deficit. Sports foods (drinks, gels, etc.) may assist in meeting training/race nutrition plans, with caffeine, and, perhaps nitrate being used as evidence-based performance supplements.
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4.
Muscle and intestinal damage in triathletes.
Tota, Ł, Piotrowska, A, Pałka, T, Morawska, M, Mikuľáková, W, Mucha, D, Żmuda-Pałka, M, Pilch, W
PloS one. 2019;(1):e0210651
Abstract
The aim of the paper was to assess indicators of muscle and intestinal damage in triathletes. The study involved 15 triathletes whose objective for the season was to start in the XTERRA POLAND 2017 event (1,500-m swimming, 36-km cycling, and 10-km mountain running). Before the 14-week preparatory period, the competitors' body composition was measured, aerobic capacity was tested (graded treadmill test) and blood samples were collected to determine markers showing the level of muscle and intestinal damage. Subsequent tests for body composition were carried out before and after the competition. Blood samples for biochemical indicators were collected the day before the competition, after the completed race, and 24 and 48 hours later. A significant decrease in body mass was observed after completing the race (-3.1±1.5%). The mean maximal oxygen uptake level among the studied athletes equalled 4.9±0.4 L·min-1, 58.8±4.5 mL·kg-1·min-1. The significant increase in concentrations of cortisol, c-reactive protein and myoglobin after the competition, significantly correlated with the significant increase in zonulin concentration (post 1h: r = 0.88, p = 0.007, r = 0,79, p = 0.001, r = 0.78, p = 0.001, and post 12h: r = 0.75, p = 0.01, r = 0.71, p = 0.011, r = 0.83, p = 0.02). No significant changes in the concentration of tumour necrosis factor alpha among the examined competitors were noted at following stages of the study. The results of our research showed that in order to monitor overload in the training of triathletes, useful markers reflecting the degree of muscle and intestinal damage include cortisol, testosterone, testosterone to cortisol ratio, c-reactive protein, myoglobin and zonulin. Changes in muscle cell damage markers strongly correlated with changes in zonulin concentration at particular stages of the study. Thus, one can expect that the concentrations of markers depicting the level of muscle cell damage after an intense and long-lasting effort will significantly influence the level of the intestinal barrier.
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5.
The effects of fatigue on the running profile of elite team sport athletes. A systematic review and meta-analysis.
Garrett, JM, Gunn, R, Eston, RG, Jakeman, J, Burgess, DJ, Norton, K
The Journal of sports medicine and physical fitness. 2019;(8):1328-1338
Abstract
INTRODUCTION With the underlying mechanisms of fatigue shown to be task-specific, gaining an understanding of changes within the running profile due to fatigue may provide a greater task-specific method for monitoring neuromuscular fatigue (NMF) in elite team sport athletes. This review aimed to identify, review and summarize the literature to understand the effects of fatigue on the running profile of elite team sport athletes. EVIDENCE ACQUISITION MEDLINE, SPORTDiscus, EMBASE and CINAHL were searched. To manage heterogeneity in athlete characteristics and sport demands, studies were limited to elite male field/court team sports, in which changes in running, gait or stride characteristics were assessed. EVIDENCE SYNTHESIS Thirteen studies were included in the analysis with changes in sprint time, kinematic variables; contact time, center of mass vertical displacement and vertical stiffness, GPS accelerometer vector variables; z and y, and mechanical parameters; velocity and V0, all shown to be sensitive measures of fatigue. Due to having at least three sets of data points, meta-analysis was run for sprint time, with results showing a significant increase immediately postexercise (effect size [ES]±95% confidence interval [CI]; 1.67±1.61, P=0.04), but no change 24 hours postexercise (ES±95% CI; 0.93±3.21, P=0.57). CONCLUSIONS The findings indicate that fatigue has a negative impact on the running profile in elite team sport athletes, offering an alternative task-specific measure of monitoring NMF in this population. However, due to large discrepancies in protocols, future research is required to allow greater uniformity in variables and methods.
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6.
A Systematic Review and Meta-Analysis of Crossover Studies Comparing Physiological, Perceptual and Performance Measures Between Treadmill and Overground Running.
Miller, JR, Van Hooren, B, Bishop, C, Buckley, JD, Willy, RW, Fuller, JT
Sports medicine (Auckland, N.Z.). 2019;(5):763-782
Abstract
BACKGROUND Treadmills are routinely used to assess running performance and training parameters related to physiological or perceived effort. These measurements are presumed to replicate overground running but there has been no systematic review comparing performance, physiology and perceived effort between treadmill and overground running. OBJECTIVE The objective of this systematic review was to compare physiological, perceptual and performance measures between treadmill and overground running in healthy adults. METHODS AMED (Allied and Contemporary Medicine), CINAHL (Cumulative Index to Nursing and Allied Health), EMBASE, MEDLINE, SCOPUS, SPORTDiscus and Web of Science databases were searched from inception until May 2018. Included studies used a crossover study design to compare physiological (oxygen uptake [[Formula: see text]O2], heart rate [HR], blood lactate concentration [La]), perceptual (rating of perceived exertion [RPE] and preferred speed) or running endurance and sprint performance (i.e. time trial duration or sprint speed) outcomes between treadmill (motorised or non-motorised) and overground running. Physiological outcomes were considered across submaximal, near-maximal and maximal running intensity subgroups. Meta-analyses were used to determine mean difference (MD) or standardised MD (SMD) ± 95% confidence intervals. RESULTS Thirty-four studies were included. Twelve studies used a 1% grade for the treadmill condition and three used grades > 1%. Similar [Formula: see text]O2 but lower La occurred during submaximal motorised treadmill running at 0% ([Formula: see text]O2 MD: - 0.55 ± 0.93 mL/kg/min; La MD: - 1.26 ± 0.71 mmol/L) and 1% ([Formula: see text]O2 MD: 0.37 ± 1.12 mL/kg/min; La MD: - 0.52 ± 0.50 mmol/L) grade than during overground running. HR and RPE during motorised treadmill running were higher at faster submaximal speeds and lower at slower submaximal speeds than during overground running. [Formula: see text]O2 (MD: - 1.25 ± 2.09 mL/kg/min) and La (MD: - 0.54 ± 0.63 mmol/L) tended to be lower, but HR (MD: 0 ± 1 bpm), and RPE (MD: - 0.4 ± 2.0 units [6-20 scale]) were similar during near-maximal motorised treadmill running to during overground running. Maximal motorised treadmill running caused similar [Formula: see text]O2 (MD: 0.78 ± 1.55 mL/kg/min) and HR (MD: - 1 ± 2 bpm) to overground running. Endurance performance was poorer (SMD: - 0.50 ± 0.36) on a motorised treadmill than overground but sprint performance varied considerably and was not significantly different (MD: - 1.4 ± 5.8 km/h). CONCLUSIONS Some, but not all, variables differ between treadmill and overground running, and may be dependent on the running speed at which they are assessed. PROTOCOL REGISTRATION CRD42017074640 (PROSPERO International Prospective Register of Systematic Reviews).
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7.
KCNA4 Gene Variant is Auxiliary in Endurance Running Performance Level.
Flecha-Velazquez, K, Fahey, TD, Martínez, JL, Lopez-Taylor, JR, Rivera, MA
International journal of sports medicine. 2019;(5):354-358
Abstract
The present is an observational study following a genetic epidemiology model using a case-control design. We tested the hypothesis of an association between the prevalence of the genotypic and allelic frequencies distribution of the potassium voltage-gated channel of the shaker related subfamily member 4 gene (KCNA4) rs1323860 (C/T transition) and endurance performance level in Hispanic male marathon runners (MR). The subjects (n=1876) were adult Hispanic male MR. Fast-MR (cases; n=938) were finishers in the top 3rd percentile. Slow MR (controls; n=938) were finishers in the lowest 3rd percentile of their respective age. Genomic DNA was purified from a whole blood sample. Polymerase chain reaction was used to amplify a KCNA4 SNP which consists of a C/T (rs1323860) transition. The observed genotype frequencies, in both Cases and Controls, met Hardy-Weinberg equilibrium (X2, P≥0.05). Genotype and allele frequencies were statistically different (P<0.01) between cases and controls. Odds ratio revealed that the C allele was 1.33 times more likely prevalent in the cases than in the controls (95% CI; 1.17, 1.51; P<0.001). The magnitude of the statistical power for the present study was 0.86. In conclusion, the findings strongly suggest that KCNA4 gene rs1323860 (C/T transition) is auxiliary in the complex phenotype of endurance running performance level in Hispanic male marathon runners.
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8.
Conservative Management and Rehabilitation in the Older Runner With Knee Osteoarthritis: An Evidence-Based Review.
Castillo, B, Sepúlveda, F, Micheo, W
American journal of physical medicine & rehabilitation. 2019;(5):416-421
Abstract
Osteoarthritis is an age-related condition that commonly affects the middle-aged and elderly population including individuals who continue to pursue an active and athletic lifestyle. Running is an easily accessible activity with many health benefits; thus, it is becoming a popular form of exercise, even in older individuals. Studies evaluating the correlation between running and osteoarthritis show conflicting results; however, most studies show an increased risk of osteoarthritis in runners with a combination of modifiable and nonmodifiable risk factors. This study reviews the current literature to provide an overview of conservative (nonpharmacological and pharmacological) management strategies including patient education, therapeutic modalities and exercises, mechanical measures, dietary factors, oral and injectable pharmacotherapies, and orthobiologics. Rehabilitation considerations and return-to-sport guidelines are discussed, emphasizing the notion that a return to running activity requires reduction in mileage and formulation of a structured exercise program that includes strengthening, flexibility, and stability exercises, as well as modifications in the running technique.
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9.
No Benefit of Ingestion of a Ketone Monoester Supplement on 10-km Running Performance.
Evans, M, McSwiney, FT, Brady, AJ, Egan, B
Medicine and science in sports and exercise. 2019;(12):2506-2515
Abstract
PURPOSE Preexercise ingestion of exogenous ketones alters the metabolic response to exercise, but effects on exercise performance have been equivocal. METHODS On two occasions in a double-blind, randomized crossover design, eight endurance-trained runners performed 1 h of submaximal exercise at approximately 65% V˙O2max immediately followed by a 10-km self-paced time trial (TT) on a motorized treadmill. An 8% carbohydrate-electrolyte solution was consumed before and during exercise, either alone (CHO + PLA), or with 573 mg·kg of a ketone monoester supplement (CHO + KME). Expired air, HR, and RPE were monitored during submaximal exercise. Serial venous blood samples were assayed for plasma glucose, lactate, and β-hydroxybutyrate concentrations. RESULTS CHO + KME produced plasma β-hydroxybutyrate concentrations of approximately 1.0 to 1.3 mM during exercise (P < 0.001), but plasma glucose and lactate concentrations were similar during exercise in both trials. V˙O2, running economy, respiratory exchange ratio, HR, and RPE were also similar between trials. Performance in the 10-km TT was not different (P = 0.483) between CHO + KME (mean, 2402 s; 95% confidence interval, 2204-2600 s) and CHO + PLA (mean, 2422 s; 95% confidence interval, 2217-2628 s). Cognitive performance, measured by reaction time and a multitasking test, did not differ between trials. CONCLUSIONS Compared with carbohydrate alone, coingestion of KME by endurance-trained athletes elevated plasma β-hydroxybutyrate concentrations, but did not improve 10-km running TT or cognitive performance.
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10.
[Effects of acute supplementation with beta-alanine on a limited time test at maximum aerobic speed on endurance athletes].
Huerta-Ojeda, Á, Contreras-Montilla, O, Galdames-Maliqueo, S, Jorquera-Aguilera, C, Fuentes-Kloss, R, Guisado-Barrilao, R
Nutricion hospitalaria. 2019;(3):698-705
Abstract
Introduction: the beta-alanine (BA) is one of the ergogenic aid most used by athletes, but the majority of the studies center the research on chronic supplementation. Objectives: to determine the acute effect of BA supplementation on a limited time test (LTT) at maximum aerobic speed (MAS) on endurance athletes. Material and method: eleven endurance athletes (VO2max 61.6 ± 9.5 mLO2•kg-1•min-1) were part of the study. The study consisted of a double-blind, cross-over intra-subject design, and the BA supplementation was 30 mg•kg-1 or placebo (PL) 60 minutes before completing a LTT. The variables were: time and distance in LTT, and post-effort lactate concentrations ([La]) in minutes 1, 3, 5, 7, and 9. The Student's t test was used for the analysis and the size of the effect (SE) was measured through Cohen's d test. Results: the time on LTT showed significant differences between BA and PL (p = 0.047; SE = 0.48). No significant differences were seen between both groups (p = 0.071; SE = 0.48), and [La] showed significant differences between both groups in minutes 3, 5 and 7, respectively (p < 0.05). Conclusion: acute supplementation with BA showed a significant increase in the execution time in LTT in the intensities connected to MAS. Hence, acute supplementation with BA is an ergogenic aid that could be considered by resistance athletes in order to increase the athletic performance.