Ioannis G Fatouros

Democritus University of Thrace, Komotina, East Macedonia and Thrace, Greece

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Publications (93)207.18 Total impact

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    ABSTRACT: Background: Pre-school age is important for developing healthy attitudes towards physical activity (PA). However, research on pre-schoolers’ pedometer-determined PA is limited. Aim: To describe pre-schoolers’ ambulatory activity; investigate step count differences in respect to Body Mass Index (BMI) categories and examine the prevalence of obesity. Subjects and methods: Pre-school aged children (n = 250; 5.5 ± 0.4 years) from Komotini (Greece) wore Omron HJ-720IT-E2 pedometers for 10 consecutive days. Height and weight were measured and BMI was calculated. Results: Three-way repeated measures ANOVAs revealed that children performed more steps on weekdays than during weekends (p < 0.001) and during leisure time than school (p < 0.001). Significant differences appeared between normal and obese children’s counts on weekdays (p < 0.001), weekend days (p < 0.05), during school (p < 0.001), after school (p < 0.005) and in weekly steps (p < 0.005). No gender differences were detected. Moreover, according to a sample t-test analysis, children’s daily steps were significantly different from the 10 000 steps/day guideline, while obesity prevalence was 15.6%. Conclusion: School-based ambulatory activity is lower than after school ambulatory activity, independent of BMI-category and gender, although obese children demonstrated fewer steps. Taking into account the high rate of both the obesity prevalence and children not meeting the 10 000 steps/day guideline, the need for preventive policies becomes obvious.
    Annals of Human Biology 08/2014; · 1.48 Impact Factor
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    ABSTRACT: Context: Irisin has been proposed to be a myokine mediating the effect of exercise on adipocyte browning. The physiology of irisin in humans is not completely understood. Objective: To study the physiology of irisin in healthy individuals with different age and fitness level and to explore direct effects of irisin on muscle metabolism. Design, Setting, and Subjects: Treadmill exercise studies were conducted to measure circulating irisin at baseline and in response to exercise among old and young, physically active and sedentary individuals. Also, high and moderate intensity swimming was performed in adolescent men and women to study the effect of exercise intensity and the time course of irisin induction by acute bouts of exercise. Human myotubes were treated with recombinant irisin and the effect on gene expression, cell signalling, and metabolism was examined. Results: Baseline circulating irisin was lower in old (vs young) and physically active (vs sedentary) subjects. Despite differences in basal levels, percent increase of irisin by acute bouts of exercise was not related to age or fitness level. Time course study revealed that circulating irisin increased immediately after high intensity interval exercise and declined 1 hr thereafter. In vitro experiments showed that irisin facilitates glucose and lipid metabolism in human muscle through AMPK phosphorylation. Conclusions: Despite the differences in basal irisin levels, exercise-induced irisin secretion is independent of age or fitness level. Increased irisin can directly modulate muscle metabolism through AMPK activation.
    The Journal of clinical endocrinology and metabolism. 08/2014;
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    ABSTRACT: Although static stretching (SS) is an integral part of physical preparation before training and competition, its usefullnes in regards to power performance improvement has been questioned. The aim of this study was to investigate the effect of six static stretching (SS) durations on speed and agility performance. According to a cross-over design, 34 trained males (age 20.5±1.4 years, height 1.81±0.2 m, weight 77.2±2.6 kg, body fat 8.2±2.6%) participated in a control session (no stretch) and six experimental conditions (10, 15, 20, 30, 40, 60 sec) performed in randomized order. Performance in speed (10 and 20 m) and agility (T-test) was measured after the control and experimental conditions. SS, consisting of stretches for hip extensors, hip adductors, knee extensors, knee flexors and ankle sole flexors, was performed after light cardiovascular exercise (8 min). A one-way repeated measures ANOVA showed that speed was improved only by SS of short duration (15/20 sec) whereas agility remained unaffected by all SS trials. When participants' speed and agility level was taken into account, it was revealed that only those of moderate performance demonstrated an improved speed (in 15- and 20-sec trials) and agility (in 10- and 15-sec trials) performance. These results suggest that short duration SS protocols induce an acute improvement of speed and agility performance whereas longer duration has neither positive nor negative effect. Furthermore, it appears that individuals of lower speed and agility performance level are more likely to benefit by a short duration SS protocol.
    Journal of strength and conditioning research / National Strength & Conditioning Association. 06/2014;
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    ABSTRACT: Abstract Basketball incorporates intense eccentric muscle activity that induces muscle microtrauma and an inflammatory response. This study investigated time-dependent inflammatory and performance responses during a weekly microcycle after a basketball match. Twenty elite-standard players underwent a trial that comprised a match followed by a 6-day simulated in-season microcycle. The trial was preceded by a control condition that did not have a match. Blood sampling and tests of maximal-intensity exercise performance and muscle damage occurred before each condition, immediately after the match and daily thereafter for 6 consecutive days. The match induced marked increases in heart rate, lactate, ammonia, glucose, non-esterified fatty acids and triglycerides. Performance deteriorated for 24-48 h after the match, whereas knee flexor and extensor soreness increased for 48 and 24 h post-match, respectively. Inflammatory (leukocytes, C-reactive protein, creatine kinase activity, adhesion molecules, cortisol, uric acid and cytokines) and oxidative stress (malondialdehyde, protein carbonyls, oxidised glutathione, antioxidant capacity, catalase and glutathione peroxidase) markers increased for ~24 h and subsided thereafter. Reduced glutathione declined for 24 h after exercise. These results suggest that a basketball match elicits moderate and relatively brief (~24-48 h) inflammatory responses, is associated with marked but short-lived performance deterioration, but is less stressful than other intermittent-type sports.
    Journal of Sports Sciences 01/2014; · 2.08 Impact Factor
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    ABSTRACT: This study investigated the time-course of performance and inflammatory responses during a simulated 6-day in-season microcycle following a team-handball game. Twenty-four handball players participated in a one-week control trial and in an experimental trial (team-handball game participation followed by a 6-day training microcycle). Concentrations of lactate, glucose, glycerol, triglecyrides, NEFA and ammonia were measured pre- and post-game. Heart rate (HR) was monitored during the game. Performance (jumping, speed, agility, line-drill testing, strength), muscle damage [knee range of motion (ROM), knee extensors/flexors delayed onset muscle soreness (DOMS), creatine kinase activity (CK)], inflammatory [leukocyte count (WBC), C-reactive protein (CRP), interleukins 1β and 6 (IL-1β, IL-6), soluble vascular adhesion molecule-1 (sVCAM-1), p-selectin, uric acid, cortisol, testosterone) and oxidative stress [malondialdehyde, protein carbonyls (PC), reduced (GSH) and oxidized glutathione (GSSG), antioxidant capacity (TAC), catalase, glutathione peroxidase activity (GPX)] markers were determined pre-game, post-game and daily for six consecutive days post-game. The game induced a marked rise of HR (∼170 beats/min), lactate (∼8-fold), glycerol (60%), NEFA (105%) and ammonia (∼62%). Performance deteriorated until 24h post-game. Knee ROM decreased (3-5%) whereas DOMS and CK increased (3-5-fold and 80-100%, respectively) 24h post-game. WBC, IL-1β, IL-6, cortisol, malondialdehyde, PC and catalase increased only immediately post-game. CRP and uric acid increased at 24h; sVCAM-1, GSSG, GPX peaked post-game and remained elevated for 24h. GSH declined until 24h post-game. Results suggest that a team-handball game represents a strong metabolic challenge and induces a short-lived and modest inflammatory response that may affect performance for as long as 24h post-game.
    The Journal of Strength and Conditioning Research 12/2013; · 1.80 Impact Factor
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    ABSTRACT: The aim of the present study was to investigate the effects of a repeated bout of eccentric exercise on health-related parameters and muscle performance on subjects undergoing atorvastatin therapy. Twenty-eight elderly men participated in the investigation and were assigned either in a control (n = 14) or in a statin therapy group (n = 14). All participants performed two isokinetic eccentric exercise bouts separated by 3 weeks. Muscle damage indices, resting energy expenditure, substrate metabolism, lipid and lipoprotein profile, as well as insulin sensitivity, were evaluated before and after eccentric. No differences in muscle function were observed between the two groups either at rest or after exercise. Eccentric exercise increased resting energy expenditure, increased fat oxidation, improved lipid profile, and increased insulin resistance 2 days after both eccentric exercise bouts. However, these changes appeared to lesser extent after the second bout. No differences were observed in the responses in the health-related parameters in the control and in the statin therapy group. Eccentric exercise affected similarly the control and the atorvastatin-treated individuals. The present results indicate that atorvastatin-treated elderly individuals may participate in various physical activities, even high-intensity muscle-damaging activities, without negative impact on muscle function and adaptation.
    Scandinavian Journal of Medicine and Science in Sports 10/2013; 23(5). · 3.21 Impact Factor
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    ABSTRACT: Eccentric exercise-induced muscle damage may cause marked alterations in insulin sensitivity. However, it is not entirely known whether such alterations are also related to changes in adipokine levels. The aim of this study was to investigate the effects of muscle damage due to downhill running on inflammation, insulin sensitivity and selected adipokines related to insulin regulation (adiponectin, visfatin, resistin). Data were collected from 12 healthy adult women. Each subject participated in two trials, 4 weeks apart. The first trial was reserved for resting measurements only (control trial), while the second trial involved a 45-min exercise (-15 % slope, ~60 % of VO2max) intervention (exercise trial). Insulin sensitivity (HOMA), creatine kinase activity (CK), delayed onset muscle soreness (DOMS), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), glucose, insulin, adiponectin, resistin, and visfatin were assessed pre-exercise and 1, 2, 3, and 4 days post-exercise and during the same time points in the control trial. Analyses revealed that CK, DOMS, TNF-α, IL-6, insulin and HOMA significantly increased (p < 0.05) throughout recovery (days 1-4). Adiponectin and visfatin remained unchanged, while resistin significantly increased (p < 0.05) only 2 days post-exercise. Visfatin was negatively correlated with HOMA at days 1 and 4 of recovery. Although muscle damage due to downhill running caused a decline of insulin sensitivity, this response was not associated with the changes in adipokine levels.
    Arbeitsphysiologie 09/2013; · 2.66 Impact Factor
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    ABSTRACT: To determine the relationship between habitual physical activity (PA) level and peripheral qualitative computed tomography-determined quantitative tibia characteristics of premenarcheal girls. Premenarcheal girls matched for age (10-13years), bone age and maturity level were assigned into: a) low PA group (LPA, n=25), b) moderate PA group (MPA, n=17), and c) high PA group (HPA, n=18). Participants' daily dietary intake, tibia's geometry and serum levels of calcium and vitamin D were assessed. Premenarcheal girls demonstrating HPA exhibited greater pericortical thickness, cross-sectional area (CSA) and bone mineral content (BMC) (p<.001) in cortical bone, greater BMC, volumetric bone density (vBMD) and polar stress strength index (SSIp) in trabecular bone (p<0.001-0.05) and greater total BMC (p<.05) and vBMD (p<.01) when compared to their physically inactive or moderately active counterparts. MPA exhibited greater values of cortical BMC (p<.01) and SSIp (p<.05) than LPA. Partial correlation analysis (adjusted for BMI) revealed modest associations between PA score and bone geometry parameters (r=0.36-0.49, p<.05) at 38% of tibia length. Habitual PA affects geometry of both cortical and trabecular areas of a long bone of premenarcheal girls in a dose-dependent manner. Specifically, PA increases both the density and size of cortical bone but only the density of trabecular bone during preadolescence. Given the importance of peak bone mass for future fracture risk, high levels of PA during childhood could be a major target for public health interventions aimed at optimising bone health in prepubertal children when the greatest bone gains occur.
    Metabolism: clinical and experimental 09/2013; · 3.10 Impact Factor
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    ABSTRACT: This study investigated the changes in oxidative stress biomarkers and antioxidant status indices caused by a 3-week high-intensity interval training (HIT) regimen. Eight physically active males performed three HIT sessions/week over 3 weeks. Each session included four to six 30-s bouts of high-intensity cycling separated by 4 minutes of recovery. Before training, acute exercise elevated protein carbonyls (PC), thiobarbituric acid reactive substances (TBARS), glutathione peroxidase (GPX) activity, total antioxidant capacity (TAC) and creatine kinase (CK), which peaked 24 h post-exercise (252±30%, 135±17%, 10±2%, 85±14% and 36±13%, above baseline, respectively; p<0.01), while catalase activity (CAT) peaked 30 min post-exercise (56±18% above baseline; p<0.01). Training attenuated the exercise-induced increase in oxidative stress markers (PC by 13.3±3.7%; TBARS by 7.2±2.7%, p<0.01) and CK activity, despite the fact that total work done was 10.9±3.6% greater in the post- compared with the pre-training exercise test. Training also induced a marked elevation of antioxidant status indices (TAC by 38.4±7.2%; CAT by 26.2±10.1%; GPX by 3.0±0.6%, p<0.01). Short-term HIT attenuates oxidative stress and up-regulates antioxidant activity after only nine training sessions totaling 22 min of high intensity exercise, further supporting its positive effect not only on physical conditioning but also on health promotion.
    Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 06/2013; · 2.99 Impact Factor
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    ABSTRACT: BACKGROUND: The major thiol-disulfide couple of reduced glutathione (GSH) and oxidized glutathione is a key regulator of major transcriptional pathways regulating aseptic inflammation and recovery of skeletal muscle after aseptic injury. Antioxidant supplementation may hamper exercise-induced cellular adaptations. OBJECTIVE: The objective was to examine how thiol-based antioxidant supplementation affects skeletal muscle's performance and redox-sensitive signaling during the inflammatory and repair phases associated with exercise-induced microtrauma. DESIGN: In a double-blind, crossover design, 10 men received placebo or N-acetylcysteine (NAC; 20 mg · kg(-1) · d(-1)) after muscle-damaging exercise (300 eccentric contractions). In each trial, muscle performance was measured at baseline, after exercise, 2 h after exercise, and daily for 8 consecutive days. Muscle biopsy samples from vastus lateralis and blood samples were collected before exercise and 2 h, 2 d, and 8 d after exercise. RESULTS: NAC attenuated the elevation of inflammatory markers of muscle damage (creatine kinase activity, C-reactive protein, proinflammatory cytokines), nuclear factor κB phosphorylation, and the decrease in strength during the first 2 d of recovery. NAC also blunted the increase in phosphorylation of protein kinase B, mammalian target of rapamycin, p70 ribosomal S6 kinase, ribosomal protein S6, and mitogen activated protein kinase p38 at 2 and 8 d after exercise. NAC also abolished the increase in myogenic determination factor and reduced tumor necrosis factor-α 8 d after exercise. Performance was completely recovered only in the placebo group. CONCLUSION: Although thiol-based antioxidant supplementation enhances GSH availability in skeletal muscle, it disrupts the skeletal muscle inflammatory response and repair capability, potentially because of a blunted activation of redox-sensitive signaling pathways. This trial was registered at clinicaltrials.gov as NCT01778309.
    American Journal of Clinical Nutrition 05/2013; · 6.50 Impact Factor
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    ABSTRACT: The purpose of this study was to examine the effect of α-lipoic acid (LA) supplementation on blood redox status in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Eight adults with G6PD deficiency (D group) and eight controls with normal G6PD levels (N group) participated in this study. Participants received LA (600mg/day) for 28days. At baseline, 2 and 4weeks after supplementation, venous blood was collected for analysis of reduced glutathione (GSH), catalase, protein carbonyls (PC), thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC), bilirubin, uric acid (UA) and hemoglobin (Hb) levels. Baseline GSH was lower (P<0.05) in D compared to N group whereas LA supplementation for 2 and 4weeks increased significantly (P<0.05) GSH levels in both groups. Catalase and TAC increased (P<0.05) in both groups following 2 and 4weeks of supplementation. Baseline TBARS values were higher (P<0.05) in D compared to N group while LA supplementation reduced (P<0.05) TBARS and PC in both groups. There were no differences for UA at baseline between the two groups but LA supplementation increased significantly UA levels only in the D group. Bilirubin and Hb were unchanged. These results indicate that LA supplementation may modulate redox status regardless G6PD deficiency.
    Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 02/2013; · 2.99 Impact Factor
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    ABSTRACT: Abstract The purpose of this study was to determine the recovery rate of football skill performance following resistance exercise of moderate or high intensity. Ten elite football players participated in three different trials: control, low-intensity resistance exercise (4 sets, 8-10 repetitions/set, 65-70% 1 repetition maximum [1RM]) and high-intensity resistance exercise (4 sets, 4-6 repetitions/set, 85-90% 1RM) in a counterbalanced manner. In each experimental condition, participants were evaluated pre, post, and at 24, 48, 72 h post exercise time points. Football skill performance was assessed through the Loughborough Soccer Passing Test, long passing, dribbling, shooting and heading. Delayed onset muscle soreness, knee joint range of motion, and muscle strength (1RM) in squat were considered as muscle damage markers. Blood samples analysed for creatine kinase activity, C-reactive protein, and leukocyte count. Passing and shooting performance declined (P < 0.05) post-exercise following resistance exercise. Strength declined post-exercise following high-intensity resistance exercise. Both trials induced only a mild muscle damage and inflammatory response in an intensity-dependent manner. These results indicate that football skill performance is minimally affected by acute resistance exercise independent of intensity suggesting that elite players may be able to participate in a football practice or match after only 24 h following a strength training session.
    Journal of Sports Sciences 01/2013; · 2.08 Impact Factor
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    ABSTRACT: The purpose of this study was to examine the intraseasonal variation of body composition (BC) in elite soccer players. 23 professional players participated in the study. Percentage of body fat (BF) was measured with the use of skinfolds. Measurements were taken monthly from the beginning until the end of the season. Measurement mean values were compared among 6 specific positional roles. For seasonal variations, the analyses of variances were performed to 11 time points across the season. BM in goalkeepers differed significantly from all other groups (p<0.001). Central defenders and lateral midfielders also differed in BM from lateral defenders, forwards and central midfielders (p<0.001). BF percentage in central defenders and lateral midfielders was significantly different from all other groups. Forwards’ BF differed significantly from that of lateral defenders and central midfielders. Besides, goalkeepers had higher BF values than central defenders (p<0.001). FFM in goalkeepers and central defenders showed significant differences from all other groups (p<0.001). Also, lateral defenders had lower FFM values than forwards and lateral midfielders. Across all players, there were significant seasonal variations in percentage of BF, whereas BM remained unchanged. The practitioners are advised to pay attention to the positional role when interpreting BC data. Changes in BM do not reflect the changes in BC.
    Serbian Journal of Sports Sciences. 01/2013; 7(1):39-44.
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    ABSTRACT: BACKGROUND: Obesity is associated with osteoarthritis and it is accompanied by chronic inflammation and elevated oxidative stress. Strengthening-type exercise is used in knee osteoarthritis (KOA) rehabilitation. This study determined how acute isokinetic exercise influences inflammatory responses of obese middle-aged women with KOA. METHODS: Ten obese women with KOA and 10 age/weight-matched controls performed an isokinetic exercise protocol. Assessment of performance (knee extensor/flexor torque), muscle soreness (DOMS), knee flexibility (KJRM), and pain, and blood collection were performed pre-exercise, post-exercise, and at 24h post-exercise. Blood was analyzed for creatine kinase activity (CK), lactate dehydrogenase activity (LDH), CRP, leukocytes, uric acid, IL-6, TBARS, lipid hydroperoxides (LPX), protein carbonyls (PC), oxidized (GSH) and reduced glutathione (GSSG), total antioxidant capacity (TAC), catalase activity, and glutathione peroxidase activity (GPX). RESULTS: Physical function remained unaltered by exercise (only torque at 90°/s decreased at 24h). Exercise increased DOMS throughout recovery but KJRM and pain remained unchanged. CK, LDH, and uric acid increased similarly in both groups. CRP remained unaffected by exercise while IL-6 increased only post-exercise. TBARS, PC, LPH, GSSG, and TAC increased only post-exercise in both groups. GSH and GSH/GSSG declined post-exercise and normalized thereafter. Catalase and GPX increased only in patients post-exercise. CONCLUSION: Isokinetic exercise induces only a mild inflammatory response of very short duration (<24h) without affecting physical function and pain in KOA patients suggesting that moderate strengthening-type exercise may be safe for this patient cohort. These results indicate that KOA patients may be able to receive another exercise stimulus after only 48h. CLINICAL RELEVANCE: Isokinetic exercise produces minimal inflammation and pain in knee osteoarthritis patients, could be performed every 48h during rehabilitation, and up-regulates patients' antioxidant system.
    The Knee 12/2012; · 2.01 Impact Factor
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    ABSTRACT: Abstract To determine the time course of performance responses after an acute bout of plyometric exercise combined with high and low intensity weight training, a 3-group (including a control group), repeated-measures design was employed. Changes in performance were monitored through jumping ability by measuring countermovement and squat jumping, and strength performance assessment through isometric and isokinetic testing of knee extensors (at two different velocities). Participants in both experimental groups performed a plyometric protocol consisting of 50 jumps over 50 cm hurdles and 50 drop jumps from a 50 cm plyometric box. Additionally, each group performed two basic weight exercises consisting of leg presses and leg extensions at 90-95% of maximum muscle strength for the high intensity group and 60% of maximum muscle strength for the low intensity group. The results of the study suggest that an acute bout of intense plyometric exercise combined with weight exercise induces time-dependent changes in performance, which are also dependent on the nature of exercise protocol and testing procedures. In conclusion, acute plyometric exercise with weight exercise may induce a substantial decline in jumping performance for as long as 72 hours but not in other forms of muscle strength.
    Journal of Sports Sciences 10/2012; · 2.08 Impact Factor
  • 2nd Congress of Biochemistry and Physiology of Exercise; 10/2012
  • 2nd Congress of Biochemistry and Physiology of Exercise; 10/2012

Publication Stats

1k Citations
207.18 Total Impact Points

Institutions

  • 2002–2014
    • Democritus University of Thrace
      • School of Medicine
      Komotina, East Macedonia and Thrace, Greece
  • 2008–2013
    • Center for Research and Technology, Thessaly
      Iolcus, Thessaly, Greece
  • 2002–2013
    • University of Thessaly
      • Department of Physical Education and Sport Science (TEFA)
      Vólos, Thessalia, Greece
  • 1997
    • University of North Carolina at Greensboro
      • Department of Exercise and Sport Science
      Greensboro, North Carolina, United States