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Time to embrace the complexity when analysing GPS data? A systematic review of contextual factors on match running in rugby league.
Dalton-Barron, N, Whitehead, S, Roe, G, Cummins, C, Beggs, C, Jones, B
Journal of sports sciences. 2020;(10):1161-1180
Abstract
This systematic review aimed to identify and summarise associations between currently identified contextual factors and match running in senior male professional rugby league. Eligible articles included at least one contextual factor and used GPS to measure at least one displacement variable within competitive senior, male, professional rugby league matches. Of the 15 included studies, the identified contextual factors were grouped into factors related to individual characteristics (n = 3), match result (n = 4), team strength (n = 2), opposition strength (n = 3), match conditions (n = 6), technical and tactical demands (n = 6), spatial and temporal characteristics (n = 7), and nutrition (n = 1). Speed was the most commonly reported measure of match running (100%), followed by distance (47%), and acceleration (20%). Inconsistencies were found between studies for most contextual factors on match running. Higher speeds were generally associated with higher fitness, encountered earlier in the match and whilst defending. All 15 studies utilised a univariate approach to quantify associations of a contextual factor. The inconsistencies found in the associations of given contextual factors highlight the complex and multi-faceted nature of match running. Therefore, practitioners should consider contextual factors when analysing and interpreting GPS data.
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2.
Acute Caffeine Mouth Rinse Does Not Change the Hydration Status following a 10 km Run in Recreationally Trained Runners.
Gonzalez, AM, Guimarães, V, Figueiredo, N, Queiroz, M, Gentil, P, Mota, JF, Pimentel, GD
BioMed research international. 2020;:6598753
Abstract
BACKGROUND AND AIMS Caffeine mouth rinsing has emerged as an alternative to oral caffeine consumption for improving performance without provoking lower gastrointestinal distress. However, it remains unclear if hydration status and sweat rate are negatively affected by caffeine mouth rinsing. This study is aimed at evaluating the effects of 10 seconds of caffeine mouth rinsing (1.2% anhydrous caffeine solution) on hydration status and sweat rate following a 10 km run trial. METHODS Ten recreationally trained runners (30.1 ± 6.4 y) volunteered to participate in this double-blind, placebo-controlled, and crossover research study. Participants completed two 10 km run trials separated by approximately one week. Immediately prior to running, participants completed a 10-second mouth rinse protocol with either 300 mg of caffeine or microcrystalline cellulose (placebo) diluted in 25 mL of water. The effects of caffeine mouth rinsing on hydration status and sweat rate were assessed following a 10 km run trial. RESULTS Sweat rate (placebo: 15.34 ± 9.71 vs. caffeine: 11.91 ± 6.98 mL · min-1; p = 0.39), dehydration (placebo: 1.20 ± 0.57 vs. caffeine: 1.49 ± 0.29%; p = 0.15), and hydration (placebo: 15.32 ± 9.71 vs. caffeine: 11.89 ± 6.99 mL · min-1; p = 0.37) measures were not significantly different between trials. CONCLUSION Caffeine mouth rinse does not appear to alter the hydration status or sweat rate following a 10 km run.
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3.
Muscle Damage and Metabolic Responses to Repeated-Sprint Running With and Without Deceleration.
Minahan, CL, Poke, DP, Morrison, J, Bellinger, PM
Journal of strength and conditioning research. 2020;(12):3423-3430
Abstract
Minahan, CL, Poke, DP, Morrison, J, and Bellinger, PM. Muscle damage and metabolic responses to repeated-sprint running with and without deceleration. J Strength Cond Res 34(12): 3423-3430, 2020-This study aimed to determine whether repeated-sprint running with deceleration aggravates markers of muscle damage or delays the recovery of performance compared with repeated-sprint running without deceleration. Fourteen male team-sport athletes performed 2 randomly ordered testing sessions on a nonmotorized treadmill with one session requiring subjects to decelerate (TMd) within 4 seconds before stopping or immediately step to the side of the treadmill belt at the completion of each sprint (TMa). Peak and mean velocities, speed decrement, blood lactate concentrations, and oxygen uptake were monitored during the repeated-sprint running protocols. Countermovement vertical jump (CMJ) performance, perceived muscle soreness, sit-and-reach flexibility, plasma creatine kinase (CK), lactate dehydrogenase (LDH), and myoglobin (Mb) concentrations were quantified immediately before and after and 45 minutes, 24 and 48 hours after repeated-sprint running protocols. Although muscle damage was indicated by increases in CK, LDH, and Mb (p ≤ 0.05) in both groups, there was no significant effect of condition (TMa vs. TMd) on any of the measured performance or physiological variables (p > 0.05). The present study indicated that the removal of deceleration from repeated-sprint running on a nonmotorized treadmill has no effect on metabolism or performance during or after repeated-sprint running or markers of muscle damage.
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Pectin-Alginate Does Not Further Enhance Exogenous Carbohydrate Oxidation in Running.
Barber, JFP, Thomas, J, Narang, B, Hengist, A, Betts, JA, Wallis, GA, Gonzalez, JT
Medicine and science in sports and exercise. 2020;(6):1376-1384
Abstract
PURPOSE Maximizing carbohydrate availability is important for many endurance events. Combining pectin and sodium alginate with ingested maltodextrin-fructose (MAL + FRU + PEC + ALG) has been suggested to enhance carbohydrate delivery via hydrogel formation, but the influence on exogenous carbohydrate oxidation remains unknown. The primary aim of this study was to assess the effects of MAL + FRU + PEC + ALG on exogenous carbohydrate oxidation during exercise compared with a maltodextrin-fructose mixture (MAL + FRU). MAL + FRU has been well established to increase exogenous carbohydrate oxidation during cycling compared with glucose-based carbohydrates (MAL + GLU). However, much evidence focuses on cycling, and direct evidence in running is lacking. Therefore, a secondary aim was to compare exogenous carbohydrate oxidation rates with MAL + FRU versus MAL + GLU during running. METHODS Nine trained runners completed two trials (MAL + FRU and MAL + FRU + PEC + ALG) in a double-blind, randomized crossover design. A subset (n = 7) also completed a MAL + GLU trial to address the secondary aim, and a water trial to establish background expired CO2 enrichment. Participants ran at 60% V˙O2peak for 120 min while ingesting either water only or carbohydrate solutions at a rate of 1.5 g carbohydrate per minute. RESULTS At the end of 120 min of exercise, exogenous carbohydrate oxidation rates were 0.9 (SD 0.5) g·min with MAL + GLU ingestion. MAL + FRU ingestion increased exogenous carbohydrate oxidation rates to 1.1 (SD 0.3) g·min (P = 0.038), with no further increase with MAL + FRU + PEC + ALG ingestion (1.1 (SD 0.3) g·min; P = 1.0). No time-treatment interaction effects were observed for plasma glucose, lactate, insulin, or nonesterified fatty acids, or for ratings of perceived exertion or gastrointestinal symptoms (all, P > 0.05). CONCLUSION To maximize exogenous carbohydrate oxidation during moderate-intensity running, athletes may benefit from consuming glucose(polymer)-fructose mixtures over glucose-based carbohydrates alone, but the addition of pectin and sodium alginate offers no further benefit.
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Reliability and Validity of a New Portable Tethered Sprint Running Test as a Measure of Maximal Anaerobic Performance.
Limmer, M, Berkholz, A, de Marées, M, Platen, P
Journal of strength and conditioning research. 2020;(8):2197-2204
Abstract
Limmer, M, Berkholz, A, de Marées, M, and Platen, P. Reliability and validity of a new portable tethered sprint running test as a measure of maximal anaerobic performance. J Strength Cond Res 34(8): 2197-2204, 2020-The purposes of this study were to develop a new portable tethered sprint running (PTSR) test for field-based anaerobic performance testing with restricted spatial conditions and the logistical challenge of carrying test equipment, and to determine reliability of the PTSR test. For validity, performance measures were compared with the cycle ergometer Wingate Anaerobic Test (WAnT) power outputs. Twelve recreationally active men and women (24.3 ± 1.6 years; 1.77 ± 0.07 m; 73.3 ± 12.5 kg) performed one familiarization trial followed by 3 randomly assigned experimental 60-second all-out effort trials consisting of one WAnT and 2 PTSR tests. All trials were performed in a randomized order on different days separated by at least 48 hours. Heart rate (HR) and maximum blood lactate concentration were recorded for each experimental trial to determine the physiological responses to the maximal efforts. Correlation coefficients indicated significant relationships between mean force (MF) and peak force (PF) in the PTSR test and mean power (MP) (r = 0.651, p = 0.022) and peak power (PP) (r = 0.877, p = 0.002) in the WAnT, but not for the fatigue index (r = 0.280, p = 0.379). In addition, both PTSR trials showed no significant differences (p > 0.05) between trials and a high reliability for the performance variables MF (intraclass correlation coefficient [ICC] = 0.98, coefficient of variation [%CV] = 7.7), PF (ICC = 0.98, %CV = 8.4), and HR (ICC = 0.92, %CV = 3.1). In conclusion, our results suggest that despite insufficient stimulation of anaerobic metabolism in some subjects resulting from poor implementation of test instructions, the PTSR is a reliable and valid test for an easy and practical assessment of maximal anaerobic performance under different field conditions.
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Nitrate-rich beetroot juice offsets salivary acidity following carbohydrate ingestion before and after endurance exercise in healthy male runners.
Burleigh, MC, Sculthorpe, N, Henriquez, FL, Easton, C
PloS one. 2020;(12):e0243755
Abstract
There have been recent calls for strategies to improve oral health in athletes. High carbohydrate diets, exercise induced dehydration and transient perturbations to immune function combine to increase oral disease risk in this group. We tested whether a single dose of nitrate (NO3-) would offset the reduction in salivary pH following carbohydrate ingestion before and after an exercise bout designed to cause mild dehydration. Eleven trained male runners ([Formula: see text] 53 ± 9 ml∙kg-1∙min-1, age 30 ± 7 years) completed a randomised placebo-controlled study comprising four experimental trials. Participants ingested the following fluids one hour before each trial: (a) 140 ml of water (negative-control), (b) 140 ml of water (positive-control), (c) 140 ml of NO3- rich beetroot juice (~12.4 mmol NO3-) (NO3- trial) or (d) 140 ml NO3- depleted beetroot juice (placebo-trial). During the negative-control trial, participants ingested 795 ml of water in three equal aliquots: before, during, and after 90 min of submaximal running. In the other trials they received 795 ml of carbohydrate supplements in the same fashion. Venous blood was collected before and after the exercise bout and saliva was sampled before and repeatedly over the 20 min following carbohydrate or water ingestion. As expected, nitrite (NO2-) and NO3- were higher in plasma and saliva during the NO3- trial than all other trials (all P<0.001). Compared to the negative-control, salivary-pH was significantly reduced following the ingestion of carbohydrate in the positive-control and placebo trials (both P <0.05). Salivary-pH was similar between the negative-control and NO3- trials before and after exercise despite ingestion of carbohydrate in the NO3- trial (both P≥0.221). Ingesting NO3- attenuates the expected reduction in salivary-pH following carbohydrate supplements and exercise-induced dehydration. NO3- should be considered by athletes as a novel nutritional strategy to reduce the risk of developing acidity related oral health conditions.
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Cold-Water Immersion Does Not Accelerate Performance Recovery After 10-km Street Run: Randomized Controlled Clinical Trial.
Dantas, G, Barros, A, Silva, B, Belém, L, Ferreira, V, Fonseca, A, Castro, P, Santos, T, Lemos, T, Hérickson, W
Research quarterly for exercise and sport. 2020;(2):228-238
Abstract
The use of strategies to assure better post-effort recovery is frequent in sports settings. There are several interventions available for exercise induced muscle damage recovery, but cold-water immersion (CWI) stands out among them. The effects of CWI are unclear in the literature and, although the number of street runners has been growing, there is a gap in the scientific evidence regarding the use of CWI to recover runners' performance after a 10-km street run. Purpose: The goal of our study was to analyze the effects of CWI on the recovery of muscle damage markers after a 10-km street run. Method: We randomly assigned thirty male recreational street runners, immediately after a 10-km street run, into three recovery groups: control (rest for 10 minutes), immersion (10 min immersed in water without ice at room temperature) and CWI (10 min immersed in water with ice at 10ºC). We assessed pain, triple hop distance, extensor peak torque and blood creatine kinase levels pre- and post-run, post-intervention and 24 hours after the run. Results: The 10-km run was enough to decrease triple hop distance and extensor peak torque, and increase levels of creatine kinase (p < 0.05); however, we found no time/group interactions in any of the assessed variables after we applied the appropriate interventions (p > 0.05). Conclusion: 10-min CWI at 10°C was no more effective than water immersion and rest in recovering muscle damage markers after 10-km runs.
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Is Motorized Treadmill Running Biomechanically Comparable to Overground Running? A Systematic Review and Meta-Analysis of Cross-Over Studies.
Van Hooren, B, Fuller, JT, Buckley, JD, Miller, JR, Sewell, K, Rao, G, Barton, C, Bishop, C, Willy, RW
Sports medicine (Auckland, N.Z.). 2020;(4):785-813
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Abstract
BACKGROUND Treadmills are often used in research, clinical practice, and training. Biomechanical investigations comparing treadmill and overground running report inconsistent findings. OBJECTIVE This study aimed at comparing biomechanical outcomes between motorized treadmill and overground running. METHODS Four databases were searched until June 2019. Crossover design studies comparing lower limb biomechanics during non-inclined, non-cushioned, quasi-constant-velocity motorized treadmill running with overground running in healthy humans (18-65 years) and written in English were included. Meta-analyses and meta-regressions were performed where possible. RESULTS 33 studies (n = 494 participants) were included. Most outcomes did not differ between running conditions. However, during treadmill running, sagittal foot-ground angle at footstrike (mean difference (MD) - 9.8° [95% confidence interval: - 13.1 to - 6.6]; low GRADE evidence), knee flexion range of motion from footstrike to peak during stance (MD 6.3° [4.5 to 8.2]; low), vertical displacement center of mass/pelvis (MD - 1.5 cm [- 2.7 to - 0.8]; low), and peak propulsive force (MD - 0.04 body weights [- 0.06 to - 0.02]; very low) were lower, while contact time (MD 5.0 ms [0.5 to 9.5]; low), knee flexion at footstrike (MD - 2.3° [- 3.6 to - 1.1]; low), and ankle sagittal plane internal joint moment (MD - 0.4 Nm/kg [- 0.7 to - 0.2]; low) were longer/higher, when pooled across overground surfaces. Conflicting findings were reported for amplitude of muscle activity. CONCLUSIONS Spatiotemporal, kinematic, kinetic, muscle activity, and muscle-tendon outcome measures are largely comparable between motorized treadmill and overground running. Considerations should, however, particularly be given to sagittal plane kinematic differences at footstrike when extrapolating treadmill running biomechanics to overground running. Protocol registration CRD42018083906 (PROSPERO International Prospective Register of Systematic Reviews).
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Sodium Bicarbonate Supplementation Does Not Improve Running Anaerobic Sprint Test Performance in Semiprofessional Adolescent Soccer Players.
Guimarães, RDS, de Morais Junior, AC, Schincaglia, RM, Saunders, B, Pimentel, GD, Mota, JF
International journal of sport nutrition and exercise metabolism. 2020;(5):330-337
Abstract
Ergogenic strategies have been studied to alleviate muscle fatigue and improve sports performance. Sodium bicarbonate (NaHCO3) has improved repeated sprint performance in adult team-sports players, but the effect for adolescents is unknown. The aim of the present study was to evaluate the effect of NaHCO3 supplementation on repeated sprint performance in semiprofessional adolescent soccer players. In a double-blind, placebo-controlled, crossover trial, 15 male semiprofessional adolescent soccer players (15 ± 1 years; body fat 10.7 ± 1.3%) ingested NaHCO3 or a placebo (sodium chloride) 90 min before performing the running anaerobic sprint test (RAST). A countermovement jump was performed before and after the RAST, and ratings of perceived exertion, blood parameters (potential hydrogen and bicarbonate concentration), and fatigue index were also evaluated. Supplementation with NaHCO3 promoted alkalosis, as demonstrated by the increase from the baseline to preexercise, compared with the placebo (potential hydrogen: +0.07 ± 0.01 vs. -0.00 ± 0.01, p < .001 and bicarbonate: +3.44 ± 0.38 vs. -1.45 ± 0.31 mmol/L, p < .001); however, this change did not translate into an improvement in RAST total time (32.12 ± 0.30 vs. 33.31 ± 0.41 s, p = .553); fatigue index (5.44 ± 0.64 vs. 6.28 ± 0.64 W/s, p = .263); ratings of perceived exertion (7.60 ± 0.33 vs. 7.80 ± 0.10 units, p = .525); countermovement jump pre-RAST (32.21 ± 3.35 vs. 32.05 ± 3.51 cm, p = .383); or countermovement jump post-RAST (31.70 ± 0.78 vs. 32.74 ± 1.11 cm, p = .696). Acute NaHCO3 supplementation did not reduce muscle fatigue or improve RAST performance in semiprofessional adolescent soccer players. More work assessing supplementation in this age group is required to increase understanding in the area.
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Effect of low energy availability during three consecutive days of endurance training on iron metabolism in male long distance runners.
Ishibashi, A, Kojima, C, Tanabe, Y, Iwayama, K, Hiroyama, T, Tsuji, T, Kamei, A, Goto, K, Takahashi, H
Physiological reports. 2020;(12):e14494
Abstract
We investigated the effect of low energy availability (LEA) during three consecutive days of endurance training on muscle glycogen content and iron metabolism. Six male long distance runners completed three consecutive days of endurance training under LEA or neutral energy availability (NEA) conditions. Energy availability was set at 20 kcal/kg fat-free mass (FFM)/day for LEA and 45 kcal/kg FFM/day for NEA. The subjects ran for 75 min at 70% of maximal oxygen uptake ( V˙ O2max ) on days 1-3. Venous blood samples were collected following an overnight fast on days 1-4, immediately and 3 hr after exercise on day 3. The muscle glycogen content on days 1-4 was evaluated by carbon-magnetic resonance spectroscopy. In LEA condition, the body weight and muscle glycogen content on days 2-4, and the FFM on days 2 and 4 were significantly lower than those on day1 (p < .05 vs. day1), whereas no significant change was observed throughout the training period in NEA condition. On day 3, muscle glycogen content before exercise was negatively correlated with serum iron level (immediately after exercise, 3 hr after exercise), serum hepcidin level immediately after exercise, and plasma IL-6 level immediately after exercise (p < .05). Moreover, serum hepcidin level on day 4 was significantly higher in LEA condition than that in NEA condition (p < .05). In conclusion, three consecutive days of endurance training under LEA reduced the muscle glycogen content with concomitant increased serum hepcidin levels in male long distance runners.