| 1. |
- Poulios, A., et al.
(författare)
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Post-Game High Protein Intake May Improve Recovery of Football-Specific Performance during a Congested Game Fixture: Results from the PRO-FOOTBALL Study
- 2018
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Ingår i: Nutrients. - : MDPI AG. - 2072-6643. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- The effects of protein supplementation on performance recovery and inflammatory responses during a simulated one-week in-season microcycle with two games (G1, G2) performed three days apart were examined. Twenty football players participated in two trials, receiving either milk protein concentrate (1.15 and 0.26 g/kg on game and training days, respectively) (PRO) or an energy-matched placebo (1.37 and 0.31 g/kg of carbohydrate on game and training days, respectively) (PLA) according to a randomized, repeated-measures, crossover, double-blind design. Each trial included two games and four daily practices. Speed, jump height, isokinetic peak torque, and muscle soreness of knee flexors (KF) and extensors (KE) were measured before G1 and daily thereafter for six days. Blood was drawn before G1 and daily thereafter. Football-specific locomotor activity and heart rate were monitored using GPS technology during games and practices. The two games resulted in reduced speed (by 3-17%), strength of knee flexors (by 12-23%), and jumping performance (by 3-10%) throughout recovery, in both trials. Average heart rate and total distance covered during games remained unchanged in PRO but not in PLA. Moreover, PRO resulted in a change of smaller magnitude in high-intensity running at the end of G2 (75-90 min vs. 0-15 min) compared to PLA (P = 0.012). KE concentric strength demonstrated a more prolonged decline in PLA (days 1 and 2 after G1, P = 0.014-0.018; days 1, 2 and 3 after G2, P = 0.016-0.037) compared to PRO (days 1 after G1, P = 0.013; days 1 and 2 after G2, P = 0.014-0.033) following both games. KF eccentric strength decreased throughout recovery after G1 (PLA: P=0.001-0.047-PRO: P =0.004-0.22) in both trials, whereas after G2 it declined throughout recovery in PLA (P = 0.000-0.013) but only during the first two days (P = 0.000-0.014) in PRO. No treatment effect was observed for delayed onset of muscle soreness, leukocyte counts, and creatine kinase activity. PRO resulted in a faster recovery of protein and lipid peroxidation markers after both games. Reduced glutathione demonstrated a more short-lived reduction after G2 in PRO compared to PLA. In summary, these results provide evidence that protein feeding may more efficiently restore football-specific performance and strength and provide antioxidant protection during a congested game fixture.
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| 2. |
- Bowtell, J. L., et al.
(författare)
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Improved Exercise Tolerance with Caffeine Is Associated with Modulation of both Peripheral and Central Neural Processes in Human Participants
- 2018
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Ingår i: Frontiers in Nutrition. - : Frontiers Media SA. - 2296-861X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Background: Caffeine has been shown to enhance exercise performance and capacity. The mechanisms remain unclear but are suggested to relate to adenosine receptor antagonism, resulting in increased central motor drive, reduced perception of effort, and altered peripheral processes such as enhanced calcium handling and extracellular potassium regulation. Our aims were to investigate how caffeine (i) affects knee extensor PCr kinetics and pH during repeated sets of single-leg knee extensor exercise to task failure and (ii) modulates the interplay between central and peripheral neural processes. We hypothesized that the caffeine-induced extension of exercise capacity during repeated sets of exercise would occur despite greater disturbance of the muscle milieu due to enhanced peripheral and corticospinal excitatory output, central motor drive, and muscle contractility. Methods: Nine healthy active young men performed five sets of intense single-leg knee extensor exercise to task failure on four separate occasions: for two visits (6 mg.kg(-1) caffeine vs placebo), quadriceps P-31-magnetic resonance spectroscopy scans were performed to quantify phosphocreatine kinetics and pH, and for the remaining two visits (6 mg.kg-1 caffeine vs placebo), femoral nerve electrical and transcranial magnetic stimulation of the quadriceps cortical motor area were applied pre- and post exercise. Results: The total exercise time was 17.9 +/- 6.0% longer in the caffeine (1,225 +/- 86 s) than in the placebo trial (1,049 +/- 73 s, p = 0.016), and muscle phosphocreatine concentration and pH (p < 0.05) were significantly lower in the latter sets of exercise after caffeine ingestion. Voluntary activation (VA) (peripheral, p = 0.007; but not supraspinal, p = 0.074), motor-evoked potential (MEP) amplitude (p = 0.007), and contractility (contraction time, p = 0.009; and relaxation rate, p = 0.003) were significantly higher after caffeine consumption, but at task failure MEP amplitude and VA were not different from placebo. Caffeine prevented the reduction in M-wave amplitude that occurred at task failure (p = 0.039). Conclusion: Caffeine supplementation improved high-intensity exercise tolerance despite greater-end exercise knee extensor phosphocreatine depletion and H+ accumulation. Caffeine-induced increases in central motor drive and corticospinal excitability were attenuated at task failure. This may have been induced by the afferent feedback of the greater disturbance of the muscle milieu, resulting in a stronger inhibitory input to the spinal and supraspinal motor neurons. However, causality needs to be established through further experiments.
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| 3. |
- Bowtell, J. L., et al.
(författare)
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Short Duration Small Sided Football and to a Lesser Extent Whole Body Vibration Exercise Induce Acute Changes in Markers of Bone Turnover
- 2016
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Ingår i: Biomed Research International. - : Hindawi Limited. - 2314-6133 .- 2314-6141.
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Tidskriftsartikel (refereegranskat)abstract
- We aimed to study whether short-duration vibration exercise or football sessions of two different durations acutely changed plasma markers of bone turnover and muscle strain. Inactive premenopausal women (n = 56) were randomized to complete a single bout of short (FG15) or long duration (FG60) small sided football or low magnitude whole body vibration training (VIB). Procollagen type 1 amino-terminal propeptide (P1NP) was increased during exercise for FG15 (51.6 +/- 23.0 to 56.5 +/- 22.5 mu g.L-1, mean +/- SD, P < 0.05) and FG60 (42.6 +/- 11.8 to 50.2 +/- 12.8 mu g.L-1, P < 0.05) but not for VIB (38.8 +/- 15.1 to 36.6 +/- 14.7 mu g.L-1, P > 0.05). An increase in osteocalcin was observed 48 h after exercise (P < 0.05), which did not differ between exercise groups. C-terminal telopeptide of type 1 collagen was not affected by exercise. Blood lactate concentration increased during exercise for FG15 (0.6 +/- 0.2 to 3.4 +/- 1.2mM) and FG60 (0.6 +/- 0.2 to 3.3 +/- 2.0 mM), but not for VIB (0.6 +/- 0.2 to 0.8 +/- 0.4mM) (P < 0.05). Plasma creatine kinase increased by 55 +/- 63% and 137 +/- 119% 48 h after FG15 and FG60 (P < 0.05), but not after VIB (26 +/- 54%, NS). In contrast to the minor elevation in osteocalcin in response to a single session of vibration exercise, both short and longer durations of small sided football acutely increased plasma P1NP, osteocalcin, and creatine kinase. This may contribute to favorable effects of chronic training on musculoskeletal health.
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| 4. |
- Connolly, L. J., et al.
(författare)
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Effects of small-volume soccer and vibration training on body composition, aerobic fitness, and muscular PCr kinetics for inactive women aged 20-45
- 2014
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Ingår i: Journal of Sport and Health Science. - : Elsevier BV. - 2095-2546. ; 3:4, s. 284-292
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The present study investigated the effects of 16 weeks of small-volume, small-sided soccer training soccer group (SG, n = 13) and oscillating whole-body vibration training vibration group (VG, n = 17) on body composition, aerobic fitness, and muscle PCr kinetics in healthy inactive premenopausal women in comparison with an inactive control group (CO, n = 14). Methods: Training for SG and VG consisted of twice-weekly 15-min sessions with average heart rates (HRs) of similar to 155 and 90 bpm respectively. Pre- and post-measurements of body composition (DXA), phosphocreatine (PCr) on-and off-kinetics, and HR measurements during standardised submaximal exercise were performed. Results: After 16 weeks of training in SG, fat percentage was lowered (p = 0.03) by 1.7% +/- 2.4% from 37.5% +/- 6.9% to 35.8% +/- 6.2% and the PCr decrease in the quadriceps during knee-extension ramp exercise was attenuated (4% +/- 8%, p = 0.04), with no changes in VG or CO (time-group effect: p = 0.03 and p = 0.03). Submaximal exercise HR was also reduced in SG after 16 weeks of training (6% +/- 5% of HRmax, p = 0.01). Conclusion: Short duration soccer training for 16 weeks appears to be sufficient to induce favourable changes in body composition and indicators of aerobic fitness and muscle oxidative capacity in untrained premenopausal women. Copyright (C) 2014, Shanghai University of Sport. Production and hosting by Elsevier B.V. All rights reserved.
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| 5. |
- Ermidis, G., et al.
(författare)
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Technical demands across playing positions of the Asian Cup in male football
- 2019
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Ingår i: International Journal of Performance Analysis in Sport. - : Informa UK Limited. - 1474-8185 .- 2474-8668. ; 19:4, s. 530-542
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to compare technical variables by playing positions in football during the 2015 Asian Cup. Top-level male football players (n = 202) that completed the full 90-min game were considered. Match-analysis data were collected using OPTA Sportsdata (www.optasports.com). Kruskal–Wallis H non-parametric test revealed that external midfielders (EM) scored more goals than fullbacks (FB) (p = 0.042), and that FB had less attempts (to score a goal) than central midfielders (CM), EM and forwards (FW), whereas central defenders (CD) had less attempts than FW (p < 0.05). CM performed more passes than CD, EM and FW, while FW performed less passes than CD, FB and CM. CD and CM performed more successful passes than FB and FW (p < 0.05), and CM also had more passes than EM (p < 0.05). Moreover, FW had more aerial duels (50–50 contests) than CM, FB and EM (p < 0.05). Similar numbers of aerial duels occurred for CD and FW. Ground duels occurred less (p < 0.05) frequently for CD compared to FB, CM, EM and FW. In conclusion, differences in technical events were observed between the various playing positions during competitive elite football matches, making it valuable considering the technical demands of players during group training as well as individualised training. © 2019, © 2019 Cardiff Metropolitan University.
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| 6. |
- Hofgaard, J., et al.
(författare)
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Effects of a 6-Week Faroese Chain Dance Programme on Postural Balance, Physical Function, and Health Profile in Elderly Subjects: A Pilot Study
- 2019
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Ingår i: Biomed Research International. - : Hindawi Limited. - 2314-6133 .- 2314-6141. ; 2019
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Tidskriftsartikel (refereegranskat)abstract
- The present pilot study investigates the impact of a Faroese chain dance intervention on health profile, mobility, and postural balance in elderly subjects. Healthy elderly subjects (n=27; age 75 +/- 5 yrs) were randomised into an intervention group (IG) and a control group (CG). IG performed twice-weekly sessions of Faroese chain dance over 6 weeks. Dancing sessions lasted 30 min in the initial 3 weeks and 45 min in the final 3 weeks. Health profile was determined before and after intervention by measuring blood pressure, resting heart rate, muscle mass, and body fat content. Postural balance was evaluated using the Berg Balance Scale (BBS) and Fullerton Advanced Balance Scale (FAB) tests, while mobility was assessed using the Short Physical Performance Battery (SPPB), the Timed Up & Go (TUG) test, the 6-min walk test, and the 30-s sit-to-stand test. Systolic and diastolic blood pressure were lowered (9 +/- 6 and 6 +/- 3 mmHg, respectively) in IG, with a tendency (P=0.07) for a greater change score than in CG. Mean arterial pressure declined (P<0.05) by 7 +/- 3 mmHg in IG, which tended (P=0.09) to be greater than in CG. IG improved (P<0.05) on BBS and FAB scores by 3.6 +/- 2.1% and 15.8 +/- 8.3%, with the change score for FAB being greater (P<0.05) than in CG (0.3 +/- 1.6). Moreover, the postintervention SPPB score was improved (P<0.05) more in IG (13.9 +/- 7.4%) compared to CG, while performance in the 30-s sit-to-stand, 6-min walk, and TUG tests improved (4-15%; P<0.05) in IG only. Body fat content was reduced (P<0.05) from 36.3 +/- 2.8% to 34.8 +/- 2.8% in IG, with no between-group differences and no change in CG (34.1 +/- 2.8% to 33.7 +/- 3.1%). In conclusion, a 6-week Faroese chain dance programme lowers blood pressure and improves postural balance and physical function in elderly.
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| 7. |
- Krustrup, P., et al.
(författare)
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Sodium bicarbonate intake improves high-intensity intermittent exercise performance in trained young men
- 2015
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Ingår i: Journal of the International Society of Sports Nutrition. - : Informa UK Limited. - 1550-2783. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sodium bicarbonate intake has been shown to improve exercise tolerance, but the effects on high-intensity intermittent exercise are less clear. Thus, the aim of the present study was to determine the effect of sodium bicarbonate intake on Yo-Yo intermittent recovery test level 2 performance in trained young men. Method: Thirteen men aged 23 +/- 1 year (height: 180 +/- 2 cm, weight: 78 +/- 3 kg; VO(2)max: 61.3 +/- 3.3 mlO(2).kg(-1).min(-1); means +/- SEM) performed the Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2) on two separate occasions in randomized order with (SBC) and without (CON) prior intake of sodium bicarbonate (0.4 g.kg(-1) body weight). Heart rate and rating of perceived exertion (RPE) were measured during the test and venous blood samples were taken frequently. Results: Yo-Yo IR2 performance was 14 % higher (P = 0.04) in SBC than in CON (735 +/- 61 vs 646 +/- 46 m, respectively). Blood pH and bicarbonate were similar between trials at baseline, but higher (P = 0.003) immediately prior to the Yo-Yo IR2 test in SBC than in CON (7.44 +/- 0.01 vs 7.32 +/- 0.01 and 33.7 +/- 3.2 vs 27.3 +/- 0.6 mmol.l(-1), respectively). Blood lactate was 0.9 +/- 0.1 and 0.8 +/- 0.1 mmol.l(-1) at baseline and increased to 11.3 +/- 1.4 and 9.4 +/- 0.8 mmoL.l(-1) at exhaustion in SBC and CON, respectively, being higher (P = 0.03) in SBC. Additionally, peak blood lactate was higher (P = 0.02) in SBC than in CON (11.7 +/- 1.2 vs 10.2 +/- 0.7 mmol.l(-1)). Blood glucose, plasma K+ and Na+ were not different between trials. Peak heart rate reached at exhaustion was 197 +/- 3 and 195 +/- 3 bpm in SBC and CON, respectively, with no difference between conditions. RPE was 7 % lower (P = 0.003) in SBC than in CON after 440 m, but similar at exhaustion (19.3 +/- 0.2 and 19.5 +/- 0.2). Conclusion: In conclusion, high-intensity intermittent exercise performance is improved by prior intake of sodium bicarbonate in trained young men, with concomitant elevations in blood alkalosis and peak blood lactate levels, as well as lowered rating of perceived exertion.
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| 8. |
- Vigh-Larsen, J. F., et al.
(författare)
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Muscle Metabolism and Fatigue during Simulated Ice Hockey Match-Play in Elite Players
- 2020
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Ingår i: Medicine and science in sports and exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 52:10, s. 2162-2171
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The present study investigated muscle metabolism and fatigue during simulated elite male ice hockey match-play. Methods: Thirty U20 male national team players completed an experimental game comprising three periods of 8 x 1-min shifts separated by 2-min recovery intervals. Two vastus lateralis biopsies were obtained either during the game (n= 7) or pregame and postgame (n= 6). Venous blood samples were drawn pregame and at the end of the first and last periods (n= 14). Activity pattern and physiological responses were continuously monitored using local positioning system and heart rate recordings. Further, repeated-sprint ability was tested pregame and after each period. Results Total distance covered was 5980 +/- 199 m with almost half the distance covered at high skating speeds (>17 km.h(-1)). Average and peak on-ice heart rate was 84% +/- 2% and 97% +/- 2% of maximum heart rate, respectively. Muscle lactate increased (P <= 0.05) more than fivefold and threefold, whereas muscle pH decreased (P <= 0.05) from 7.31 +/- 0.04 pregame to 6.99 +/- 0.07 and 7.13 +/- 0.11 during the first and last periods, respectively. Muscle glycogen decreased by 53% postgame (P <= 0.05) with similar to 65% of fast- and slow-twitch fibers depleted of glycogen. Blood lactate increased sixfold (P <= 0.05), whereas plasma free fatty acid levels increased 1.5-fold and threefold (P <= 0.05) after the first and last periods. Repeated-sprint ability was impaired (similar to 3%;P <= 0.05) postgame concomitant with a similar to 10% decrease in the number of accelerations and decelerations during the second and last periods (P <= 0.05). Conclusions Our findings demonstrate that a simulated ice hockey match-play scenario encompasses a high on-ice heart rate response and glycolytic loading resulting in a marked degradation of muscle glycogen, particularly in specific sub-groups of fibers. This may be of importance both for fatigue in the final stages of a game and for subsequent recovery.
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