| 1. |
- Draganidis, D., et al.
(författare)
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Recovery Kinetics of Knee Flexor and Extensor Strength after a Football Match
- 2015
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 10:6
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Tidskriftsartikel (refereegranskat)abstract
- We examined the temporal changes of isokinetic strength performance of knee flexor (KF) and extensor (KE) strength after a footballmatch. Players were randomly assigned to a control (N = 14, participated only in measurements and practices) or an experimental group (N = 20, participated also in a football match). Participants trained daily during the two days after the match. Match and training overload was monitored with GPS devices. Venous blood was sampled and muscle damage was assessed pre-match, post-match and at 12h, 36h and 60h post-match. Isometric strength as well as eccentric and concentric peak torque of knee flexors and extensors in both limbs (dominant and non-dominant) were measured on an isokinetic dynamometer at baseline and at 12h, 36h and 60h after the match. Functional (KFecc/KEcon) and conventional (KFcon/KEcon) ratios were then calculated. Only eccentric peak torque of knee flexors declined at 60h after the match in the control group. In the experimental group: a) isometric strength of knee extensors and knee flexors declined (P<0.05) at 12h (both limbs) and 36h (dominant limb only), b) eccentric and concentric peak torque of knee extensors and flexors declined (P<0.05) in both limbs for 36h at 60 degrees/s and for 60h at 180 degrees/s with eccentric peak torque of knee flexors demonstrating a greater (P<0.05) reduction than concentric peak torque, c) strength deterioration was greater (P<0.05) at 180 degrees/s and in dominant limb, d) the functional ratio was more sensitive tomatch-induced fatigue demonstrating a more prolonged decline. Discriminant and regression analysis revealed that strength deterioration and recovery may be related to the amount of eccentric actions performed during the match and athletes' football-specific conditioning. Our data suggest that recovery kinetics of knee flexor and extensor strength after a football match demonstrate strength, limb and velocity specificity and may depend on match physical overload and players' physical conditioning level.
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| 2. |
- Girard, O., et al.
(författare)
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Plantar flexor neuromuscular adjustments following match-play football in hot and cool conditions
- 2015
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Ingår i: Scandinavian Journal of Medicine & Science in Sports. - : Wiley. - 0905-7188. ; 25:S1, s. 154-163
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Tidskriftsartikel (refereegranskat)abstract
- We assessed neuromuscular fatigue and recovery of the plantar flexors after playing football with or without severe heat stress. Neuromuscular characteristics of the plantar flexors were assessed in 17 male players at baseline and approximate to 30min, 24, and 48h after two 90-min football matches in temperate (approximate to 20 degrees C and 55% rH) and hot (approximate to 43 degrees C and 20% rH) environments. Measurements included maximal voluntary strength, muscle activation, twitch contractile properties, and rate of torque development and soleus EMG (i.e., root mean square activity) rise from 0 to 30, -50, -100, and -200 ms during maximal isometric contractions for plantar flexors. Voluntary activation and peak twitch torque were equally reduced (-1.5% and -16.5%, respectively; P<0.05) post-matches relative to baseline in both conditions, the latter persisting for at least 48h, whereas strength losses (approximate to 5%) were not significant. Absolute explosive force production declined (P<0.05) 30ms after contraction onset independently of condition, with no change at any other epochs. Globally, normalized rate of force development and soleus EMG activity rise values remained unchanged. In football, match-induced alterations in maximal and rapid torque production capacities of the plantar flexors are moderate and do not differ after competing in temperate and hot environments.
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| 3. |
- Jamurtas, A. Z., et al.
(författare)
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Iron status markers are only transiently affected by a football game
- 2015
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Ingår i: Journal of Sports Sciences. - : Informa UK Limited. - 0264-0414 .- 1466-447X. ; 33:20, s. 2088-2099
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Tidskriftsartikel (refereegranskat)abstract
- We examined the temporal variation of iron’s status markers during a 60h period following a football game. Thirty-four male football players were randomly assigned to a control group (CG, N=14, participated only in measurements and training) or an experimental group (EG, N=20, took part in a football game one week after the completion of the competitive season). All participants trained regularly for two consecutive days after the game. Training and game load was monitored with high time-resolution global positioning system (GPS) devices. Blood samples were collected and muscle damage markers and repeated sprint ability (RSA) were assessed pre-game and at 2h, 12h 36h and 60h post-game. No changes were noted in CG. Iron concentration decreased (P<0.05) 2h post-game and normalised thereafter whereas total iron binding capacity increased (P<0.05) 12–60h of recovery (P<0.05). Erythrocytes, haemoglobin (HGB) concentration, plasma volume, haematocrit, mean cell volume, mean cell HGB, mean cell HGB concentration, red cell width-SD, red cell width-CV, ferritin concentration and transferrin saturation remained unaltered during the intervention period. Creatine kinase activity and muscle soreness increased (P<0.05) throughout recovery in EG. RSA declined (P<0.05) until 36h of recovery and normalised thereafter. Our data demonstrate that iron status markers are only transiently affected by a football game. © 2015 Taylor & Francis.
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| 4. |
- 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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| 5. |
- Krustrup, P., et al.
(författare)
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The Yo-Yo IE2 Test: Physiological Response for Untrained Men versus Trained Soccer Players
- 2015
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Ingår i: Medicine and Science in Sports and Exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131. ; 47:1, s. 100-108
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Tidskriftsartikel (refereegranskat)abstract
- Purpose This study aimed to examine the physical capacity and physiological response to the Yo-Yo Intermittent Endurance level 2 test (IE2) for untrained individuals (UTR) and trained male soccer players (TR) and to investigate the determinants of intense intermittent exercise performance. Methods Thirty-four healthy UTR males and 15 age-matched TR performed a maximal incremental treadmill test and a Yo-Yo IE2 test. Muscle biopsies and blood samples were obtained, and heart rate (HR) was measured before, during, and after tests. Results UTR had a 67% lower (P < 0.01) Yo-Yo IE2 performance (665 271 vs 2027 +/- 298 m; effect size (ES), 4.8), 34% lower VO2max (P < 0.01), and 19% lower resting muscle glycogen (P < 0.05) than those of TR. Blood lactate concentration and HR during the first 560 m of the Yo-Yo IE2 test were higher (P < 0.01) in UTR than those in TR (560 m, 7.4 +/- 2.8 vs 2.4 +/- 0.8 mM; ES, 1.7-2.8; 188 +/- 11 vs 173 +/- 8 bpm; ES, 0.9-1.5), with no differences at exhaustion. Time >95% HRmax was lower (P < 0.01) in UTR than that in TR (1.0 +/- 1.1 vs 6.3 +/- 2.9 min; ES, 3.1). Mean rates of muscle creatine phosphate utilization (16.5 +/- 9.5 vs 4.3 +/- 2.7 mmolkg(-1) d.wmin(-1)), muscle lactate accumulation (16.8 +/- 9.1 vs 4.2 +/- 2.9 mmolkg(-1) d.w.min(-1)), and glycogen breakdown (29.6 +/- 14.2 vs 7.7 +/- 5.4 mmolkg(-1) d.w.min(-1)) were fourfold higher (P < 0.01; ES, 1.4-1.7) in UTR than those in TR. For UTR, correlations (P < 0.01) were observed between Yo-Yo IE2 performance and VO2max (r = 0.77), incremental treadmill test performance (r = 0.79), and muscle citrate synthase activity (r = 0.57) but not for TR (r = -0.12 to 0.50; P > 0.05). Conclusions The Yo-Yo IE2 test was shown to possess high construct validity by showing large differences in performance, HR, and anaerobic metabolism between UTR and TR. In addition, VO2max seemed to be important for intermittent exercise performance in UTR but not for TR.
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| 6. |
- Marriott, M., et al.
(författare)
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Ergogenic effects of caffeine and sodium bicarbonate supplementation on intermittent exercise performance preceded by intense arm cranking exercise
- 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: Caffeine and sodium bicarbonate ingestion have been suggested to improve high-intensity intermittent exercise, but it is unclear if these ergogenic substances affect performance under provoked metabolic acidification. To study the effects of caffeine and sodium bicarbonate on intense intermittent exercise performance and metabolic markers under exercise-induced acidification, intense arm-cranking exercise was performed prior to intense intermittent running after intake of placebo, caffeine and sodium bicarbonate. Methods: Male team-sports athletes (n = 12) ingested sodium bicarbonate (NaHCO3; 0.4 g.kg(-1) b.w.), caffeine (CAF; 6 mg.kg(-1) b.w.) or placebo (PLA) on three different occasions. Thereafter, participants engaged in intense arm exercise prior to the Yo-Yo intermittent recovery test level-2 (Yo-Yo IR2). Heart rate, blood lactate and glucose as well as rating of perceived exertion (RPE) were determined during the protocol. Results: CAF and NaHCO3 elicited a 14 and 23% improvement (P < 0.05), respectively, in Yo-Yo IR2 performance, post arm exercise compared to PLA. The NaHCO3 trial displayed higher [blood lactate] (P < 0.05) compared to CAF and PLA (10.5 +/- 1.9 vs. 8.8 +/- 1.7 and 7.7 +/- 2.0 mmol.L-1, respectively) after the Yo-Yo IR2. At exhaustion CAF demonstrated higher (P < 0.05) [blood glucose] compared to PLA and NaHCO3 (5.5 +/- 0.7 vs. 4.2 +/- 0.9 vs. 4.1 +/- 0.9 mmol.L-1, respectively). RPE was lower (P < 0.05) during the Yo-Yo IR2 test in the NaHCO3 trial in comparison to CAF and PLA, while no difference in heart rate was observed between trials. Conclusions: Caffeine and sodium bicarbonate administration improved Yo-Yo IR2 performance and lowered perceived exertion after intense arm cranking exercise, with greater overall effects of sodium bicarbonate intake.
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| 7. |
- Milanovic, Z., et al.
(författare)
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Health-Related Physical Fitness in Healthy Untrained Men: Effects on VO(2)max, Jump Performance and Flexibility of Soccer and Moderate-Intensity Continuous Running
- 2015
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 10:8
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to determine the effects of recreational soccer (SOC) compared to moderate-intensity continuous running (RUN) on all health-related physical fitness components in healthy untrained men. Sixty-nine participants were recruited and randomly assigned to one of three groups, of which sixty-four completed the study: a soccer training group (SOC; n = 20, 34 +/- 4 (means +/- SD) years, 78.1 +/- 8.3 kg, 179 +/- 4 cm); a running group (RUN; n = 21, 32 +/- 4 years, 78.0 +/- 5.5 kg, 179 +/- 7 cm); or a passive control group (CON; n = 23, 30 +/- 3 years, 76.6 +/- 12.0 kg, 178 +/- 8 cm). The training intervention lasted 12 weeks and consisted of three 60-min sessions per week. All participants were tested for each of the following physical fitness components: maximal aerobic power, minute ventilation, maximal heart rate, squat jump (SJ), countermovement jump with arm swing (CMJ), sit-and-reach flexibility, and body composition. Over the 12 weeks, VO(2)max relative to body weight increased more (p<0.05) in SOC (24.2%, ES = 1.20) and RUN (21.5%, ES = 1.17) than in CON (-5.0%, ES = -0.24), partly due to large changes in body mass (-5.9, -5.7 and +2.6 kg, p<0.05 for SOC, RUN and CON, respectively). Over the 12 weeks, SJ and CMJ performance increased more (p<0.05) in SOC (14.8 and 12.1%, ES = 1.08 and 0.81) than in RUN (3.3 and 3.0%, ES = 0.23 and 0.19) and CON (0.3 and 0.2%), while flexibility also increased more (p<0.05) in SOC (94%, ES = 0.97) than in RUN and CON (0-2%). In conclusion, untrained men displayed marked improvements in maximal aerobic power after 12 weeks of soccer training and moderate-intensity running, partly due to large decreases in body mass. Additionally soccer training induced pronounced positive effects on jump performance and flexibility, making soccer an effective broad-spectrum fitness training intervention.
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| 8. |
- Mohr, Magni, 1973, et al.
(författare)
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Effects of soccer vs swim training on bone formation in sedentary middle-aged women
- 2015
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 115:12, s. 2671-2679
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The present study examined the effects of 15weeks of soccer training and two different swimming training protocols on bone turnover in sedentary middle-aged women. Methods: Eighty-three premenopausal mildly hypertensive women [age: 45±6 (±SD)years, height: 165±6cm, weight: 80.0±14.1kg, body fat: 42.6±5.7%, systolic blood pressure/diastolic blood pressure: 138±6/85±3mmHg] were randomized into soccer training (SOC, n=21), high-intensity intermittent swimming (HS, n=21), moderate-intensity swimming (MS, n=21) intervention groups, and a control group (C, n=20). The training groups completed three sessions per week for 15weeks. DXA scans were performed and resting blood samples were drawn pre- and post-intervention. Results: In SOC, plasma osteocalcin, procollagen type I N propeptide and C-terminal telopeptide increased (P<0.05) by 37±15, 52±23 and 42±18%, respectively, with no changes in MS, HS and C. The intervention-induced increase in SOC was larger (P<0.05) than in MS, HS and C. In SOC, leg BMC increased (P<0.05) by 3.1±4.5%, with a larger increase in SOC than inC. Femoral shaft and trochanter bone mineral density (BMD) increased (P<0.05) by 1.7±1.9 and 2.4±2.9%, respectively, in SOC, with a greater (P<0.05) change in SOC than inMS and C, whereas total body and total leg BMD did not change in any of the groups. Conclusion: In conclusion, 15weeks of soccer training with sedentary middle-aged women caused marked increases in bone turnover markers, with concomitant increases in leg bone mass. No changes in bone formation and resorption markers were seen after prolonged submaximal or high-intensity intermittent swimming training. Thus, soccer training appears to provide a powerful osteogenic stimulus in middle-aged women. © 2015, Springer-Verlag Berlin Heidelberg.
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| 9. |
- Nordsborg, N. B., et al.
(författare)
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Oxidative capacity and glycogen content increase more in arm than leg muscle in sedentary women after intense training
- 2015
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Ingår i: Journal of Applied Physiology. - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 119:2, s. 116-123
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Tidskriftsartikel (refereegranskat)abstract
- The hypothesis that the adaptive capacity is higher in human upper- than lower-body skeletal muscle was tested. Furthermore, the hypothesis that more pronounced adaptations in upper-body musculature can be achieved by "low-volume high-intensity" compared with "high-volume low-intensity" exercise training was evaluated. A group of sedentary premenopausal women aged 45 +/- 6 yr (+/- SD) with expected high adaptive potential in both upper- and lower-extremity muscle groups participated. After random allocation to high-intensity swimming (HIS, n = 21), moderate-intensity swimming (MOS, n = 21), soccer (SOC, n = 21) or a nontraining control group (CON, n = 20), the training groups completed three workouts per week for 15 wk. Resting muscle biopsies were obtained from the vastus lateralis muscle and deltoideus muscle before and after the intervention. After the training intervention, a larger (P < 0.05) increase existed in deltoideus muscle of the HIS group compared with vastus lateralis muscle of the SOC group for citrate synthase maximal activity (95 +/- 89 vs. 27 +/- 34%), citrate synthase protein expression (100 +/- 29 vs. 31 +/- 44%), 3-hydroxyacyl-CoA dehydrogenase maximal activity (35 +/- 43 vs. 3 +/- 25%), muscle glycogen content (63 +/- 76 vs. 20 +/- 51%), and expression of mitochondrial complex II, III, and IV. Additionally, HIS caused higher (P < 0.05) increases than MOS in deltoideus muscle citrate synthase maximal activity, citrate synthase protein expression, and muscle glycogen content. In conclusion, the deltoideus muscle has a higher adaptive potential than the vastus lateralis muscle in sedentary women, and "high-intensity low-volume" training is a more efficient regime than "low-intensity high-volume" training for increasing the aerobic capacity of the deltoideus muscle.
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| 10. |
- Peter, Krustrup, et al.
(författare)
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Physical Demands in Competitive Ultimate Frisbee
- 2015
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Ingår i: Journal of Strength and Conditioning Research. - 1064-8011. ; 29:12, s. 3386-3391
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Tidskriftsartikel (refereegranskat)abstract
- Krustrup, P and Mohr, M. Physical demands in competitive ultimate Frisbee. J Strength Cond Res 29(12): 3386-3391, 2015-The objective was to study game demands in competitive ultimate Frisbee by performing match analysis during a game. Thirteen moderately trained (Yo-Yo intermittent recovery test levels 1 and 2 [Yo-Yo IR1 and IR2] performance: 1790 ± 382 m and 657 ± 225 m, respectively) competitive male ultimate Frisbee athletes played a game in which activity profile using Global Positioning System (GPS) technology and heart rate (HR) were recorded. Game HRmean and HRpeak were 82 ± 2% and 99 ± 1% of maximum heart rate, respectively. Total game distance was 4.70 ± 0.47 km, of which 0.63 ± 0.14 km was high-intensity running and 0.21 ± 0.11 km was sprinting. In the second half, 10% less (p ≤ 0.05) ground was covered with high-intensity running compared with the first half (0.28 ± 0.08 km vs. 0.31 ± 0.07 km). Less (43-47%; p ≤ 0.05) high-intensity running was performed in the third 9-minute period of each half compared with the first two 9-minute periods of the same half. Players performed 17.4 ± 5.7 sprints during the match. Yo-Yo IR2 performance correlated to the amount of high-intensity running in the last 9 minutes of both halves (r = 0.69, p ≤ 0.05), whereas Yo-Yo IR1 performance correlated with total sprint distance (r = 0.74, p ≤ 0.05). Ultimate Frisbee is an intense intermittent team sport with high cardiovascular loading and clear indications of fatigue toward the end of each half. Yo-Yo IR test performances correlate with physical match performance.
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