Refine
Year of publication
Document Type
- Article (178)
- Postprint (92)
- Review (15)
- Other (9)
- Monograph/Edited Volume (1)
- Conference Proceeding (1)
Keywords
- football (26)
- resistance training (19)
- adolescents (17)
- youth (15)
- athletic performance (14)
- balance (13)
- exercise (12)
- performance (11)
- strength training (11)
- stretch-shortening cycle (11)
- children (10)
- monitoring (10)
- muscle strength (10)
- training (10)
- training load (10)
- postural control (9)
- Exercise (8)
- Gait (8)
- electromyography (8)
- elite athletes (8)
- gait (8)
- injury risk (8)
- power (8)
- strength (8)
- young athletes (8)
- plyometric training (7)
- Stretch-shortening cycle (6)
- aging (6)
- muscle power (6)
- physical fitness (6)
- physiology (6)
- postural stability (6)
- Electromyography (5)
- Ground reaction force (5)
- Resistance training (5)
- force (5)
- injury (5)
- jumping (5)
- movement (5)
- periodization (5)
- plyometric exercise (5)
- sport-specific performance (5)
- striking combat sports (5)
- working memory (5)
- youth sports (5)
- Aging (4)
- Balance (4)
- EMG (4)
- Performance (4)
- Team sports (4)
- agility (4)
- change of direction (4)
- global positioning system (4)
- ground reaction force (4)
- human physical conditioning (4)
- inertial measurement unit (4)
- loading rate (4)
- muscle (4)
- physical performance (4)
- postural sway (4)
- rate of perceived exertion (4)
- recovery (4)
- rolling averages (4)
- running (4)
- sensitivity (4)
- soccer (4)
- speed (4)
- validity (4)
- weighted moving averages (4)
- Body composition (3)
- COVID-19 (3)
- EEG (3)
- Postural stability (3)
- RPE (3)
- Seniors (3)
- Trunk muscle strength (3)
- Walking (3)
- Youth (3)
- adolescent (3)
- attentional demand (3)
- balance training (3)
- biomechanics (3)
- cardiorespiratory fitness (3)
- child (3)
- cognitive performance (3)
- cognitive-postural dual task (3)
- elderly (3)
- fatigue (3)
- gait analysis (3)
- ground reaction forces (3)
- hospitalization (3)
- maturation (3)
- maturity (3)
- modality compatibility (3)
- motor skills (3)
- musculoskeletal and neural physiological phenomena (3)
- oarsmen (3)
- on-water performance (3)
- peak height velocity (3)
- physical conditioning human (3)
- plyometrics (3)
- range of motion (3)
- rate of torque development (3)
- reliability (3)
- running mechanics (3)
- somatic variables (3)
- talent (3)
- youth athletes (3)
- youth soccer (3)
- ACWR (2)
- Acceleration (2)
- Acute Recovery and Stress Scale (ARSS) (2)
- Children (2)
- Cognitive fatigue (2)
- Cognitive interference (2)
- Cognitive/motor interference (2)
- Computer Software (2)
- Conditioning activity (2)
- Countermovement jump (2)
- DXA (2)
- Daily life (2)
- Detraining (2)
- Exertion (2)
- Fatigue (2)
- Flat feet (2)
- Football (2)
- Footwear (2)
- Ginkgo biloba extract (2)
- Healthy aging (2)
- Injury risk (2)
- Jugendliche (2)
- Jump height (2)
- Kampfsport (2)
- Kinder (2)
- Kinematics (2)
- Linear regression analysis (2)
- Maximalkraft (2)
- Mobility (2)
- Motion (2)
- Muscle (2)
- Muscle mass (2)
- Muscle strength (2)
- OptoGait (2)
- Overhead athletes (2)
- Physical fitness (2)
- Postural control (2)
- Power (2)
- Principal component analysis (2)
- Proactive/reactive balance (2)
- RGB-D cameras (2)
- Recovery (2)
- Repeated sprint (2)
- Scanning electron microscopy (2)
- Schnellkraft (2)
- Short‐term effect (2)
- Shoulder (2)
- Single/dual tasking (2)
- Speed (2)
- Sport-specific performance (2)
- Steady-state balance (2)
- Stress levels (2)
- Sway (2)
- Swimming performance (2)
- Tiredness (2)
- Velocity (2)
- Widerstandstraining (2)
- Young swimmers (2)
- Zebris (2)
- academy (2)
- acute chronic workload ratio (2)
- aerobic metabolism (2)
- aerobic power (2)
- allometry (2)
- alpha-2 (2)
- ankles (2)
- anterior cruciate ligament (2)
- anthropometry (2)
- anxiety (2)
- apoptosis (2)
- balance strategy (2)
- barbell velocity (2)
- biological age (2)
- biological maturation (2)
- blood (2)
- blood sample (2)
- body density (2)
- body limbs (2)
- body shape (2)
- calcaneal eversion (2)
- canoe racing (2)
- cardiomyopathy (2)
- change of direction speed (2)
- change-of-direction speed (2)
- cognitive interference (2)
- cognitive/muscular fatigue (2)
- combat sport (2)
- comparison of devices (2)
- concurrent training (2)
- conditioning activity (2)
- conditioning exercise (2)
- core strength (2)
- cross-education (2)
- data pipeline (2)
- depression (2)
- diabetes (2)
- diabetes mellitus (2)
- diabetic (2)
- digital health (2)
- drop jump (2)
- dual task (2)
- dual-task costs (2)
- early sport specialization (2)
- eccentric-plyometric (2)
- endurance performance (2)
- evaluation (2)
- exercise intervention (2)
- exercise test (2)
- exercise training (2)
- external load (2)
- external training load (2)
- eyedness (2)
- fMRI (2)
- feet (2)
- fitness tests (2)
- flat feet (2)
- footedness (2)
- force production (2)
- functional performance (2)
- gait analysis algorithm (2)
- gait speed (2)
- gender differences (2)
- hamstring muscles (2)
- heart rate (2)
- hematocrit (2)
- high-intensity-interval training (2)
- hip (2)
- hormones (2)
- human motion (2)
- immune system (2)
- internal load (2)
- jump performance (2)
- jump training (2)
- jumps (2)
- kinetics (2)
- knee joint angle (2)
- knee osteoarthritis (2)
- knees (2)
- late childhood (2)
- latency (2)
- laterality (2)
- limb overuse conditions (2)
- linear sprint (2)
- long-term (2)
- low-back-pain (2)
- lower limb mechanics (2)
- lower-extremity kinematics (2)
- martial arts (2)
- matched time (2)
- material fatigue (2)
- medial longitudinal arch (2)
- mental imagery (2)
- meta-analysis (2)
- methodological quality (2)
- miRNAs (2)
- mitochondrial adaptation (2)
- mobility disability (2)
- motion capture (2)
- motor-performance (2)
- muscle activation (2)
- muscle coactivation (2)
- muscle fitness (2)
- muscle metabolism (2)
- muscular endurance (2)
- muscular strength (2)
- of-direction speed (2)
- overreaching (2)
- overtraining (2)
- oxygen consumption (2)
- passive stretching (2)
- peak torque (2)
- pelvic alignment (2)
- pervasive healthcare (2)
- physical fitness expertise (2)
- physiological strain (2)
- postural balance (2)
- power training (2)
- prevention (2)
- public dataset (2)
- race time (2)
- randomized controlled-trial (2)
- responses (2)
- return-to-sport (2)
- rotation (2)
- rugby league players (2)
- schedule (2)
- scholastic demands (2)
- school baseball players (2)
- sensorimotor training (2)
- sex-differences (2)
- skeletal joints (2)
- specific assessment (2)
- specificity (2)
- sportliche Leistung (2)
- sports (2)
- sprint (2)
- sprinting (2)
- sprints (2)
- stability (2)
- standing position (2)
- taekwondo electronic scoring system (2)
- taekwondo-specific testing (2)
- tasks (2)
- team sport (2)
- theta (2)
- time-efficient exercise (2)
- track and field (2)
- training adaptation (2)
- training intensity (2)
- twitch torque (2)
- unstable walkway (2)
- virus infection (2)
- water sports (2)
- weight lifting (2)
- weight loss (2)
- weight training (2)
- weightlifting (2)
- whole-body vibratoin (2)
- women (2)
- young soccer players (2)
- youth sport (2)
- Accelerometer (1)
- Alpha-2 (1)
- Association (1)
- Athlete testing (1)
- Attention (1)
- Balance Tests (1)
- Biomechanics (1)
- Bow leg (1)
- Central activation (1)
- Cognition motor (1)
- Cognitive enhancer (1)
- Cognitive skills (1)
- Core stability (1)
- Core strength (1)
- Cross-over fatigue (1)
- Crossover (1)
- Crossover fatigue (1)
- Developmental gains (1)
- Dual tasks (1)
- EMOTIKON (1)
- EXERCISE (1)
- Elderly (1)
- Electric stimulation (1)
- Electroencephalography (EEG) (1)
- Electromyography (EMG) (1)
- Elite sports (1)
- Endocrine (1)
- Endurance (1)
- Executive function (1)
- Exercise therapy (1)
- Exhaustion (1)
- Explosive force production (1)
- Fall risk (1)
- Fall risk assessment (1)
- Falls (1)
- Field test (1)
- Force (1)
- Force production (1)
- Frail elderly (1)
- Free moment (1)
- Functional magnetic resonance imaging (fMRI) (1)
- Gait biomechanics (1)
- Gait kinematics (1)
- Gait kinetics (1)
- Gym-based/home-based training (1)
- ICA (1)
- Instability (1)
- Intensity Dose -response relationship (1)
- Isokinetic (1)
- Judo-specific pulling movement (1)
- Jumping height (1)
- Keyage children (1)
- Kindergarten (1)
- Knee valgus (1)
- Knee valgus motion (1)
- Lateral jumps (1)
- Linear Mixed Models (1)
- Loading rate (1)
- Lower-extremity muscle power (1)
- MUSCLE (1)
- Maturation (1)
- Maximal isometric force (1)
- Maximal voluntary contraction (MVC) (1)
- Metabolism (1)
- Mild cognitive impairment (1)
- Morote-seoi-nage (1)
- Motor function (1)
- Motor performance (1)
- Motor skills (1)
- Movement velocity (1)
- Multiple sclerosis (1)
- Muscle contraction (1)
- Muscle power (1)
- Muscle torque (1)
- Oberflächenelektromyografie (1)
- Older-than-keyage children (1)
- Optojump system (1)
- Parkinson's disease (1)
- Pediatric gait (1)
- Performance gains (1)
- Physical Fitness (1)
- Physical performance (1)
- Plyometric exercise (1)
- Plyometrics (1)
- Post-activation potentiation (1)
- Postactivation potentiation (1)
- Postural Control (1)
- Postural balance (1)
- Power training (1)
- Preventive therapy (1)
- Primary school (1)
- Primary school children (1)
- Quadriceps muscle (1)
- Quadriceps strength (1)
- Quarantine (1)
- Reactive movement (1)
- Reflex (1)
- Sensorimotor training (1)
- Skill (1)
- Squat jump (1)
- Strength training (1)
- Stress (1)
- Theraband training (1)
- Theta (1)
- Transcranial magnetic brain stimulation (TMS) (1)
- Vertec device (1)
- WALKING (1)
- Walking speed (1)
- Work ability (1)
- adolescent athletes (1)
- aerobic exercise (1)
- age (1)
- annual training (1)
- assessment (1)
- athlete testing (1)
- athlete. (1)
- athletes (1)
- athletic (1)
- attention (1)
- ball speed (1)
- ballistic training (1)
- blood lactate (1)
- bone (1)
- boys (1)
- causal mediation analysis (1)
- climbing (1)
- cognitive enhancer (1)
- cognitive skills (1)
- cognitive/motor interference (1)
- combat sports (1)
- conditioning stimulus (1)
- core (1)
- deconditioning (1)
- detraining (1)
- directed acyclic graphs (1)
- dominant limb (1)
- dose-response relation (1)
- dose-response relationship (1)
- electroencephalography (1)
- elite (1)
- elite sport (1)
- endocrine (1)
- endurance (1)
- energetic systems (1)
- executive function (1)
- exhaustion (1)
- explosive force production (1)
- fall risk assessment (1)
- field test (1)
- fitness (1)
- flat foot (1)
- flexibility (1)
- footwear (1)
- free moment (1)
- function (1)
- fundamental movement skill (1)
- gender (1)
- girls (1)
- hearing loss (1)
- high effect size (1)
- high-intensity interval training (1)
- impact loading (1)
- infection (1)
- injury prevention (1)
- instability resistance training (1)
- intermittent sport (1)
- intervention (1)
- jump (1)
- jump height (1)
- jump height/power (1)
- jump performances (1)
- jump/sprint exercises (1)
- jumping ability (1)
- kindergarten (1)
- knee (1)
- knee flexion angle (1)
- knee valgus angle (1)
- knee valgus motion (1)
- leg extensors (1)
- load carriage (1)
- load-velocity (1)
- load–velocity relationship (1)
- locomotor skill (1)
- maximal isometric contraction (1)
- maximal isometric torque (1)
- maximum voluntary contraction (1)
- metabolism (1)
- mild cognitive impairment (1)
- motivational climate (1)
- motor performance (1)
- motor skill (1)
- muscle activity (1)
- muscular power (1)
- musculature (1)
- myofascial (1)
- neuromuscular rolling (1)
- non-dominant limb (1)
- optimal load (1)
- patients (1)
- performance gains (1)
- physical activity (1)
- physical activity program (1)
- physical fitness test (1)
- post-activation potentiation (1)
- preactivation (1)
- pressure (1)
- primary school (1)
- proactive/reactive balance (1)
- progression (1)
- proprioception (1)
- race (1)
- rate of force development (1)
- reactive movement (1)
- reflex (1)
- region/point elastic gym floor (1)
- relationship (1)
- relationships (1)
- running velocity (1)
- sedentary (1)
- self massage (1)
- self-massage therapy (1)
- self-myofascial release (1)
- seniors (1)
- sensory input (1)
- shoe (1)
- short latency response (1)
- shoulder girdle (1)
- shoulder strength (1)
- single/dual tasking (1)
- ski jumping (1)
- skill (1)
- soccer players (1)
- specific strength training (1)
- spezifisches Krafttraining (1)
- sport profile (1)
- static/dynamic postural control (1)
- steady-state balance (1)
- stroke (1)
- structured (1)
- surface electromyography (1)
- task difficulty (1)
- tendon stiffness (1)
- test-retest reliability (1)
- therapy (1)
- time (1)
- torque (1)
- training specificity (1)
- vertical jump height (1)
- vestibular (1)
- virus (1)
- walking (1)
- work (1)
- work-rate distribution (1)
- young (1)
- young adults (1)
Institute
- Department Sport- und Gesundheitswissenschaften (126)
- Strukturbereich Kognitionswissenschaften (108)
- Humanwissenschaftliche Fakultät (22)
- Extern (17)
- Department Psychologie (9)
- Hasso-Plattner-Institut für Digital Engineering GmbH (6)
- Fakultät für Gesundheitswissenschaften (3)
- Mathematisch-Naturwissenschaftliche Fakultät (3)
- Fachgruppe Soziologie (1)
The purpose of this study was to examine the test-retest reliability, and convergent and discriminative validity of a new taekwondo-specific change-of-direction (COD) speed test with striking techniques (TST) in elite taekwondo athletes. Twenty (10 males and 10 females) elite (athletes who compete at national level) and top-elite (athletes who compete at national and international level) taekwondo athletes with an average training background of 8.9 ± 1.3 years of systematic taekwondo training participated in this study. During the two-week test-retest period, various generic performance tests measuring COD speed, balance, speed, and jump performance were carried out during the first week and as a retest during the second week. Three TST trials were conducted with each athlete and the best trial was used for further analyses. The relevant performance measure derived from the TST was the time with striking penalty (TST-TSP). TST-TSP performances amounted to 10.57 ± 1.08 s for males and 11.74 ± 1.34 s for females. The reliability analysis of the TST performance was conducted after logarithmic transformation, in order to address the problem of heteroscedasticity. In both groups, the TST demonstrated a high relative test-retest reliability (intraclass correlation coefficients and 90% compatibility limits were 0.80 and 0.47 to 0.93, respectively). For absolute reliability, the TST’s typical error of measurement (TEM), 90% compatibility limits, and magnitudes were 4.6%, 3.4 to 7.7, for males, and 5.4%, 3.9 to 9.0, for females. The homogeneous sample of taekwondo athletes meant that the TST’s TEM exceeded the usual smallest important change (SIC) with 0.2 effect size in the two groups. The new test showed mostly very large correlations with linear sprint speed (r = 0.71 to 0.85) and dynamic balance (r = −0.71 and −0.74), large correlations with COD speed (r = 0.57 to 0.60) and vertical jump performance (r = −0.50 to −0.65), and moderate correlations with horizontal jump performance (r = −0.34 to −0.45) and static balance (r = −0.39 to −0.44). Top-elite athletes showed better TST performances than elite counterparts. Receiver operating characteristic analysis indicated that the TST effectively discriminated between top-elite and elite taekwondo athletes. In conclusion, the TST is a valid, and sensitive test to evaluate the COD speed with taekwondo specific skills, and reliable when considering ICC and TEM. Although the usefulness of the TST is questioned to detect small performance changes in the present population, the TST can detect moderate changes in taekwondo-specific COD speed.
Physical fatigue (PF) negatively affects postural control, resulting in impaired balance performance in young and older adults. Similar effects on postural control can be observed for mental fatigue (MF) mainly in older adults. Controversial results exist for young adults. There is a void in the literature on the effects of fatigue on balance and cortical activity. Therefore, this study aimed to examine the acute effects of PF and MF on postural sway and cortical activity. Fifteen healthy young adults aged 28 ± 3 years participated in this study. MF and PF protocols comprising of an all-out repeated sit-to-stand task and a computer-based attention network test, respectively, were applied in random order. Pre and post fatigue, cortical activity and postural sway (i.e., center of pressure displacements [CoPd], velocity [CoPv], and CoP variability [CV CoPd, CV CoPv]) were tested during a challenging bipedal balance board task. Absolute spectral power was calculated for theta (4–7.5 Hz), alpha-2 (10.5–12.5 Hz), beta-1 (13–18 Hz), and beta-2 (18.5–25 Hz) in frontal, central, and parietal regions of interest (ROI) and baseline-normalized. Inference statistics revealed a significant time-by-fatigue interaction for CoPd (p = 0.009, d = 0.39, Δ 9.2%) and CoPv (p = 0.009, d = 0.36, Δ 9.2%), and a significant main effect of time for CoP variability (CV CoPd: p = 0.001, d = 0.84; CV CoPv: p = 0.05, d = 0.62). Post hoc analyses showed a significant increase in CoPd (p = 0.002, d = 1.03) and CoPv (p = 0.003, d = 1.03) following PF but not MF. For cortical activity, a significant time-by-fatigue interaction was found for relative alpha-2 power in parietal (p < 0.001, d = 0.06) areas. Post hoc tests indicated larger alpha-2 power increases after PF (p < 0.001, d = 1.69, Δ 3.9%) compared to MF (p = 0.001, d = 1.03, Δ 2.5%). In addition, changes in parietal alpha-2 power and measures of postural sway did not correlate significantly, irrespective of the applied fatigue protocol. No significant changes were found for the other frequency bands, irrespective of the fatigue protocol and ROI under investigation. Thus, the applied PF protocol resulted in increased postural sway (CoPd and CoPv) and CoP variability accompanied by enhanced alpha-2 power in the parietal ROI while MF led to increased CoP variability and alpha-2 power in our sample of young adults. Potential underlying cortical mechanisms responsible for the greater increase in parietal alpha-2 power after PF were discussed but could not be clearly identified as cause. Therefore, further future research is needed to decipher alternative interpretations.
Injuries in professional soccer are a significant concern for teams, and they are caused amongst others by high training load. This cohort study describes the relationship between workload parameters and the occurrence of non-contact injuries, during weeks with high and low workload in professional soccer players throughout the season. Twenty-one professional soccer players aged 28.3 ± 3.9 yrs. who competed in the Iranian Persian Gulf Pro League participated in this 48-week study. The external load was monitored using global positioning system (GPS, GPSPORTS Systems Pty Ltd) and the type of injury was documented daily by the team's medical staff. Odds ratio (OR) and relative risk (RR) were calculated for non-contact injuries for high- and low-load weeks according to acute (AW), chronic (CW), acute to chronic workload ratio (ACWR), and AW variation (Δ-Acute) values. By using Poisson distribution, the interval between previous and new injuries were estimated. Overall, 12 non-contact injuries occurred during high load and 9 during low load weeks. Based on the variables ACWR and Δ-AW, there was a significantly increased risk of sustaining non-contact injuries (p < 0.05) during high-load weeks for ACWR (OR: 4.67), and Δ-AW (OR: 4.07). Finally, the expected time between injuries was significantly shorter in high load weeks for ACWR [1.25 vs. 3.33, rate ratio time (RRT)] and Δ-AW (1.33 vs. 3.45, RRT) respectively, compared to low load weeks. The risk of sustaining injuries was significantly larger during high workload weeks for ACWR, and Δ-AW compared with low workload weeks. The observed high OR in high load weeks indicate that there is a significant relationship between workload and occurrence of non-contact injuries. The predicted time to new injuries is shorter in high load weeks compared to low load weeks. Therefore, the frequency of injuries is higher during high load weeks for ACWR and Δ-AW. ACWR and Δ-AW appear to be good indicators for estimating the injury risk, and the time interval between injuries.
The purpose of this study was to examine the test-retest reliability, and convergent and discriminative validity of a new taekwondo-specific change-of-direction (COD) speed test with striking techniques (TST) in elite taekwondo athletes. Twenty (10 males and 10 females) elite (athletes who compete at national level) and top-elite (athletes who compete at national and international level) taekwondo athletes with an average training background of 8.9 ± 1.3 years of systematic taekwondo training participated in this study. During the two-week test-retest period, various generic performance tests measuring COD speed, balance, speed, and jump performance were carried out during the first week and as a retest during the second week. Three TST trials were conducted with each athlete and the best trial was used for further analyses. The relevant performance measure derived from the TST was the time with striking penalty (TST-TSP). TST-TSP performances amounted to 10.57 ± 1.08 s for males and 11.74 ± 1.34 s for females. The reliability analysis of the TST performance was conducted after logarithmic transformation, in order to address the problem of heteroscedasticity. In both groups, the TST demonstrated a high relative test-retest reliability (intraclass correlation coefficients and 90% compatibility limits were 0.80 and 0.47 to 0.93, respectively). For absolute reliability, the TST’s typical error of measurement (TEM), 90% compatibility limits, and magnitudes were 4.6%, 3.4 to 7.7, for males, and 5.4%, 3.9 to 9.0, for females. The homogeneous sample of taekwondo athletes meant that the TST’s TEM exceeded the usual smallest important change (SIC) with 0.2 effect size in the two groups. The new test showed mostly very large correlations with linear sprint speed (r = 0.71 to 0.85) and dynamic balance (r = −0.71 and −0.74), large correlations with COD speed (r = 0.57 to 0.60) and vertical jump performance (r = −0.50 to −0.65), and moderate correlations with horizontal jump performance (r = −0.34 to −0.45) and static balance (r = −0.39 to −0.44). Top-elite athletes showed better TST performances than elite counterparts. Receiver operating characteristic analysis indicated that the TST effectively discriminated between top-elite and elite taekwondo athletes. In conclusion, the TST is a valid, and sensitive test to evaluate the COD speed with taekwondo specific skills, and reliable when considering ICC and TEM. Although the usefulness of the TST is questioned to detect small performance changes in the present population, the TST can detect moderate changes in taekwondo-specific COD speed.
The prevalence of obesity in the pediatric population has become a major public health issue. Indeed, the dramatic increase of this epidemic causes multiple and harmful consequences, Physical activity, particularly physical exercise, remains to be the cornerstone of interventions against childhood obesity. Given the conflicting findings with reference to the relevant literature addressing the effects of exercise on adiposity and physical fitness outcomes in obese children and adolescents, the effect of duration-matched concurrent training (CT) [50% resistance (RT) and 50% high-intensity-interval-training (HIIT)] on body composition and physical fitness in obese youth remains to be elucidated. Thus, the purpose of this study was to examine the effects of 9-weeks of CT compared to RT or HIIT alone, on body composition and selected physical fitness components in healthy sedentary obese youth. Out of 73 participants, only 37; [14 males and 23 females; age 13.4 ± 0.9 years; body-mass-index (BMI): 31.2 ± 4.8 kg·m-2] were eligible and randomized into three groups: HIIT (n = 12): 3-4 sets×12 runs at 80–110% peak velocity, with 10-s passive recovery between bouts; RT (n = 12): 6 exercises; 3–4 sets × 10 repetition maximum (RM) and CT (n = 13): 50% serial completion of RT and HIIT. CT promoted significant greater gains compared to HIIT and RT on body composition (p < 0.01, d = large), 6-min-walking test distance (6 MWT-distance) and on 6 MWT-VO2max (p < 0.03, d = large). In addition, CT showed substantially greater improvements than HIIT in the medicine ball throw test (20.2 vs. 13.6%, p < 0.04, d = large). On the other hand, RT exhibited significantly greater gains in relative hand grip strength (p < 0.03, d = large) and CMJ (p < 0.01, d = large) than HIIT and CT. CT promoted greater benefits for fat, body mass loss and cardiorespiratory fitness than HIIT or RT modalities. This study provides important information for practitioners and therapists on the application of effective exercise regimes with obese youth to induce significant and beneficial body composition changes. The applied CT program and the respective programming parameters in terms of exercise intensity and volume can be used by practitioners as an effective exercise treatment to fight the pandemic overweight and obesity in youth.
Physical fatigue (PF) negatively affects postural control, resulting in impaired balance performance in young and older adults. Similar effects on postural control can be observed for mental fatigue (MF) mainly in older adults. Controversial results exist for young adults. There is a void in the literature on the effects of fatigue on balance and cortical activity. Therefore, this study aimed to examine the acute effects of PF and MF on postural sway and cortical activity. Fifteen healthy young adults aged 28 ± 3 years participated in this study. MF and PF protocols comprising of an all-out repeated sit-to-stand task and a computer-based attention network test, respectively, were applied in random order. Pre and post fatigue, cortical activity and postural sway (i.e., center of pressure displacements [CoPd], velocity [CoPv], and CoP variability [CV CoPd, CV CoPv]) were tested during a challenging bipedal balance board task. Absolute spectral power was calculated for theta (4–7.5 Hz), alpha-2 (10.5–12.5 Hz), beta-1 (13–18 Hz), and beta-2 (18.5–25 Hz) in frontal, central, and parietal regions of interest (ROI) and baseline-normalized. Inference statistics revealed a significant time-by-fatigue interaction for CoPd (p = 0.009, d = 0.39, Δ 9.2%) and CoPv (p = 0.009, d = 0.36, Δ 9.2%), and a significant main effect of time for CoP variability (CV CoPd: p = 0.001, d = 0.84; CV CoPv: p = 0.05, d = 0.62). Post hoc analyses showed a significant increase in CoPd (p = 0.002, d = 1.03) and CoPv (p = 0.003, d = 1.03) following PF but not MF. For cortical activity, a significant time-by-fatigue interaction was found for relative alpha-2 power in parietal (p < 0.001, d = 0.06) areas. Post hoc tests indicated larger alpha-2 power increases after PF (p < 0.001, d = 1.69, Δ 3.9%) compared to MF (p = 0.001, d = 1.03, Δ 2.5%). In addition, changes in parietal alpha-2 power and measures of postural sway did not correlate significantly, irrespective of the applied fatigue protocol. No significant changes were found for the other frequency bands, irrespective of the fatigue protocol and ROI under investigation. Thus, the applied PF protocol resulted in increased postural sway (CoPd and CoPv) and CoP variability accompanied by enhanced alpha-2 power in the parietal ROI while MF led to increased CoP variability and alpha-2 power in our sample of young adults. Potential underlying cortical mechanisms responsible for the greater increase in parietal alpha-2 power after PF were discussed but could not be clearly identified as cause. Therefore, further future research is needed to decipher alternative interpretations.
Aims: High intensity interval training (HIIT) improves mitochondrial characteristics. This study compared the impact of two workload-matched high intensity interval training (HIIT) protocols with different work:recovery ratios on regulatory factors related to mitochondrial biogenesis in the soleus muscle of diabetic rats.
Materials and methods: Twenty-four Wistar rats were randomly divided into four equal-sized groups: non-diabetic control, diabetic control (DC), diabetic with long recovery exercise [4–5 × 2-min running at 80%–90% of the maximum speed reached with 2-min of recovery at 40% of the maximum speed reached (DHIIT1:1)], and diabetic with short recovery exercise (5–6 × 2-min running at 80%–90% of the maximum speed reached with 1-min of recovery at 30% of the maximum speed reached [DHIIT2:1]). Both HIIT protocols were completed five times/week for 4 weeks while maintaining equal running distances in each session.
Results: Gene and protein expressions of PGC-1α, p53, and citrate synthase of the muscles increased significantly following DHIIT1:1 and DHIIT2:1 compared to DC (p ˂ 0.05). Most parameters, except for PGC-1α protein (p = 0.597), were significantly higher in DHIIT2:1 than in DHIIT1:1 (p ˂ 0.05). Both DHIIT groups showed significant increases in maximum speed with larger increases in DHIIT2:1 compared with DHIIT1:1.
Conclusion: Our findings indicate that both HIIT protocols can potently up-regulate gene and protein expression of PGC-1α, p53, and CS. However, DHIIT2:1 has superior effects compared with DHIIT1:1 in improving mitochondrial adaptive responses in diabetic rats.
Background: In terms of physiological and biomechanical characteristics, over-pronation of the feet has been associated with distinct muscle recruitment patterns and ground reaction forces during running.
Objective: The aim of this study was to evaluate the effects of running on sand vs. stable ground on ground-reaction-forces (GRFs) and electromyographic (EMG) activity of lower limb muscles in individuals with over-pronated feet (OPF) compared with healthy controls.
Methods: Thirty-three OPF individuals and 33 controls ran at preferred speed and in randomized-order over level-ground and sand. A force-plate was embedded in an 18-m runway to collect GRFs. Muscle activities were recorded using an EMG-system. Data were adjusted for surface-related differences in running speed.
Results: Running on sand resulted in lower speed compared with stable ground running (p < 0.001; d = 0.83). Results demonstrated that running on sand produced higher tibialis anterior activity (p = 0.024; d = 0.28). Also, findings indicated larger loading rates (p = 0.004; d = 0.72) and greater vastus medialis (p < 0.001; d = 0.89) and rectus femoris (p = 0.001; d = 0.61) activities in OPF individuals. Controls but not OPF showed significantly lower gluteus-medius activity (p = 0.022; d = 0.63) when running on sand.
Conclusion: Running on sand resulted in lower running speed and higher tibialis anterior activity during the loading phase. This may indicate alterations in neuromuscular demands in the distal part of the lower limbs when running on sand. In OPF individuals, higher loading rates together with greater quadriceps activity may constitute a proximal compensatory mechanism for distal surface instability.
Cognitive resources contribute to balance control. There is evidence that mental fatigue reduces cognitive resources and impairs balance performance, particularly in older adults and when balance tasks are complex, for example when trying to walk or stand while concurrently performing a secondary cognitive task.
We conducted a systematic literature search in PubMed (MEDLINE), Web of Science and Google Scholar to identify eligible studies and performed a random effects meta-analysis to quantify the effects of experimentally induced mental fatigue on balance performance in healthy adults. Subgroup analyses were computed for age (healthy young vs. healthy older adults) and balance task complexity (balance tasks with high complexity vs. balance tasks with low complexity) to examine the moderating effects of these factors on fatigue-mediated balance performance.
We identified 7 eligible studies with 9 study groups and 206 participants. Analysis revealed that performing a prolonged cognitive task had a small but significant effect (SMDwm = −0.38) on subsequent balance performance in healthy young and older adults. However, age- and task-related differences in balance responses to fatigue could not be confirmed statistically.
Overall, aggregation of the available literature indicates that mental fatigue generally reduces balance in healthy adults. However, interactions between cognitive resource reduction, aging and balance task complexity remain elusive.
Injuries in professional soccer are a significant concern for teams, and they are caused amongst others by high training load. This cohort study describes the relationship between workload parameters and the occurrence of non-contact injuries, during weeks with high and low workload in professional soccer players throughout the season. Twenty-one professional soccer players aged 28.3 ± 3.9 yrs. who competed in the Iranian Persian Gulf Pro League participated in this 48-week study. The external load was monitored using global positioning system (GPS, GPSPORTS Systems Pty Ltd) and the type of injury was documented daily by the team's medical staff. Odds ratio (OR) and relative risk (RR) were calculated for non-contact injuries for high- and low-load weeks according to acute (AW), chronic (CW), acute to chronic workload ratio (ACWR), and AW variation (Δ-Acute) values. By using Poisson distribution, the interval between previous and new injuries were estimated. Overall, 12 non-contact injuries occurred during high load and 9 during low load weeks. Based on the variables ACWR and Δ-AW, there was a significantly increased risk of sustaining non-contact injuries (p < 0.05) during high-load weeks for ACWR (OR: 4.67), and Δ-AW (OR: 4.07). Finally, the expected time between injuries was significantly shorter in high load weeks for ACWR [1.25 vs. 3.33, rate ratio time (RRT)] and Δ-AW (1.33 vs. 3.45, RRT) respectively, compared to low load weeks. The risk of sustaining injuries was significantly larger during high workload weeks for ACWR, and Δ-AW compared with low workload weeks. The observed high OR in high load weeks indicate that there is a significant relationship between workload and occurrence of non-contact injuries. The predicted time to new injuries is shorter in high load weeks compared to low load weeks. Therefore, the frequency of injuries is higher during high load weeks for ACWR and Δ-AW. ACWR and Δ-AW appear to be good indicators for estimating the injury risk, and the time interval between injuries.