Refine
Year of publication
Document Type
- Article (191)
- 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)
- exercise (14)
- balance (13)
- performance (11)
- strength training (11)
- stretch-shortening cycle (11)
- training (11)
- children (10)
- monitoring (10)
- muscle strength (10)
- training load (10)
- postural control (9)
- power (9)
- Exercise (8)
- Gait (8)
- electromyography (8)
- elite athletes (8)
- gait (8)
- injury risk (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)
- recovery (5)
- speed (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)
- Youth (4)
- agility (4)
- change of direction (4)
- elderly (4)
- global positioning system (4)
- ground reaction force (4)
- human physical conditioning (4)
- inertial measurement unit (4)
- loading rate (4)
- modality compatibility (4)
- muscle (4)
- physical performance (4)
- postural sway (4)
- rate of perceived exertion (4)
- rolling averages (4)
- running (4)
- sensitivity (4)
- soccer (4)
- validity (4)
- weighted moving averages (4)
- Body composition (3)
- COVID-19 (3)
- EEG (3)
- Fatigue (3)
- Physical fitness (3)
- Postural stability (3)
- Power (3)
- RPE (3)
- Seniors (3)
- Trunk muscle strength (3)
- Walking (3)
- adolescent (3)
- apoptosis (3)
- attentional demand (3)
- balance training (3)
- biomechanics (3)
- cardiomyopathy (3)
- cardiorespiratory fitness (3)
- child (3)
- cognitive performance (3)
- cognitive-postural dual task (3)
- diabetes (3)
- dual task (3)
- fatigue (3)
- gait analysis (3)
- ground reaction forces (3)
- hospitalization (3)
- maturation (3)
- maturity (3)
- miRNAs (3)
- motor skills (3)
- musculoskeletal and neural physiological phenomena (3)
- oarsmen (3)
- on-water performance (3)
- overreaching (3)
- overtraining (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)
- Crossover (2)
- DXA (2)
- Daily life (2)
- Detraining (2)
- EMOTIKON (2)
- Exertion (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 power (2)
- Muscle strength (2)
- OptoGait (2)
- Overhead athletes (2)
- Postural control (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 exercise (2)
- aerobic metabolism (2)
- aerobic power (2)
- allometry (2)
- alpha-2 (2)
- ankles (2)
- anterior cruciate ligament (2)
- anthropometry (2)
- anxiety (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)
- 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 mellitus (2)
- diabetic (2)
- digital health (2)
- drop jump (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)
- 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)
- 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)
- work-rate distribution (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)
- Cardiorespiratory endurance (1)
- Central activation (1)
- Cognition motor (1)
- Cognitive enhancer (1)
- Cognitive skills (1)
- Cohort study (1)
- Core stability (1)
- Core strength (1)
- Cross-over fatigue (1)
- Crossover fatigue (1)
- Developmental gains (1)
- Dual tasks (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)
- Flexibility (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)
- Health care (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)
- 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)
- Mental fatigue (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 torque (1)
- Neural inhibition (1)
- Oberflächenelektromyografie (1)
- Older-than-keyage children (1)
- Optojump system (1)
- Paediatrics (1)
- Parkinson's disease (1)
- Pediatric gait (1)
- Performance gains (1)
- Physical Fitness (1)
- Physical performance (1)
- Physiology (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)
- Sars-CoV-2 (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)
- activities (1)
- adolescent athletes (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)
- blood lactate; (1)
- bone (1)
- boys (1)
- causal mediation analysis (1)
- climbing (1)
- cognitive enhancer (1)
- cognitive function (1)
- cognitive skills (1)
- cognitive/motor interference (1)
- combat sports (1)
- conditioning stimulus (1)
- congested calendar (1)
- core (1)
- crosstalk (1)
- deconditioning (1)
- detraining (1)
- directed acyclic graphs (1)
- dominant limb (1)
- dose response (1)
- dose-response relation (1)
- dose-response relationship (1)
- electroencephalography (1)
- elite (1)
- elite sport (1)
- endocrine (1)
- endurance (1)
- energetic systems (1)
- executive control (1)
- executive function (1)
- exercise prescription (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)
- maximal strength (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)
- of daily living (1)
- optimal load (1)
- patients (1)
- performance gains (1)
- physical activity (1)
- physical activity program (1)
- physical fitness test (1)
- post-activation potentiation (1)
- practice (1)
- preactivation (1)
- pressure (1)
- primary school (1)
- proactive/reactive balance (1)
- progression (1)
- proprioception (1)
- race (1)
- rate of force development (1)
- rating of perceived exertion (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)
- snatch (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)
- time series analysis (1)
- torque (1)
- training intervention (1)
- training specificity (1)
- vertical jump height (1)
- vestibular (1)
- virus (1)
- walking (1)
- walking capacity (1)
- walking speed (1)
- work (1)
- young (1)
- young adults (1)
Institute
- Department Sport- und Gesundheitswissenschaften (143)
- Strukturbereich Kognitionswissenschaften (105)
- Humanwissenschaftliche Fakultät (22)
- Extern (14)
- Department Psychologie (8)
- Hasso-Plattner-Institut für Digital Engineering GmbH (6)
- Fakultät für Gesundheitswissenschaften (3)
- Mathematisch-Naturwissenschaftliche Fakultät (3)
- Fachgruppe Soziologie (1)
- Hasso-Plattner-Institut für Digital Engineering gGmbH (1)
Background: Infection with human immunodeficiency virus (HIV) affects muscle mass, altering independent activities of people living with HIV (PLWH). Resistance training alone (RT) or combined with aerobic exercise (AE) is linked to improved muscle mass and strength maintenance in PLWH. These exercise benefits have been the focus of different meta-analyses, although only a limited number of studies have been identified up to the year 2013/4. An up-to-date systematic review and meta-analysis concerning the effect of RT alone or combined with AE on strength parameters and hormones is of high value, since more and recent studies dealing with these types of exercise in PLWH have been published. Methods: Randomized controlled trials evaluating the effects of RT alone, AE alone or the combination of both (AERT) on PLWH was performed through five web-databases up to December 2017. Risk of bias and study quality was attained using the PEDro scale. Weighted mean difference (WMD) from baseline to post-intervention changes was calculated. The I2 statistics for heterogeneity was calculated. Results: Thirteen studies reported strength outcomes. Eight studies presented a low risk of bias. The overall change in upper body strength was 19.3 Kg (95% CI: 9.8±28.8, p< 0.001) after AERT and 17.5 Kg (95% CI: 16±19.1, p< 0.001) for RT. Lower body change was 29.4 Kg (95% CI: 18.1±40.8, p< 0.001) after RT and 10.2 Kg (95% CI: 6.7±13.8, p< 0.001) for AERT. Changes were higher after controlling for the risk of bias in upper and lower body strength and for supervised exercise in lower body strength. A significant change towards lower levels of IL-6 was found (-2.4 ng/dl (95% CI: -2.6, -2.1, p< 0.001). Conclusion: Both resistance training alone and combined with aerobic exercise showed a positive change when studies with low risk of bias and professional supervision were analyzed, improving upper and, more critically, lower body muscle strength. Also, this study found that exercise had a lowering effect on IL-6 levels in PLWH.
Combining training of muscle strength and cardiorespiratory fitness within a training cycle could increase athletic performance more than single-mode training. However, the physiological effects produced by each training modality could also interfere with each other, improving athletic performance less than single-mode training. Because anthropometric, physiological, and biomechanical differences between young and adult athletes can affect the responses to exercise training, young athletes might respond differently to concurrent training (CT) compared with adults. Thus, the aim of the present systematic review with meta-analysis was to determine the effects of concurrent strength and endurance training on selected physical fitness components and athletic performance in youth. A systematic literature search of PubMed and Web of Science identified 886 records. The studies included in the analyses examined children (girls age 6–11 years, boys age 6–13 years) or adolescents (girls age 12–18 years, boys age 14–18 years), compared CT with single-mode endurance (ET) or strength training (ST), and reported at least one strength/power—(e.g., jump height), endurance—(e.g., peak V°O2, exercise economy), or performance-related (e.g., time trial) outcome. We calculated weighted standardized mean differences (SMDs). CT compared to ET produced small effects in favor of CT on athletic performance (n = 11 studies, SMD = 0.41, p = 0.04) and trivial effects on cardiorespiratory endurance (n = 4 studies, SMD = 0.04, p = 0.86) and exercise economy (n = 5 studies, SMD = 0.16, p = 0.49) in young athletes. A sub-analysis of chronological age revealed a trend toward larger effects of CT vs. ET on athletic performance in adolescents (SMD = 0.52) compared with children (SMD = 0.17). CT compared with ST had small effects in favor of CT on muscle power (n = 4 studies, SMD = 0.23, p = 0.04). In conclusion, CT is more effective than single-mode ET or ST in improving selected measures of physical fitness and athletic performance in youth. Specifically, CT compared with ET improved athletic performance in children and particularly adolescents. Finally, CT was more effective than ST in improving muscle power in youth.
Power training programs have proved to be effective in improving components of physical fitness such as speed. According to the concept of training specificity, it was postulated that exercises must attempt to closely mimic the demands of the respective activity. When transferring this idea to speed development, the purpose of the present study was to examine the effects of resisted sprint (RST) vs. traditional power training (TPT) on physical fitness in healthy young adults. Thirty-five healthy, physically active adults were randomly assigned to a RST (n = 10, 23 ± 3 years), a TPT (n = 9, 23 ± 3 years), or a passive control group (n = 16, 23 ± 2 years). RST and TPT exercised for 6 weeks with three training sessions/week each lasting 45–60 min. RST comprised frontal and lateral sprint exercises using an expander system with increasing levels of resistance that was attached to a treadmill (h/p/cosmos). TPT included ballistic strength training at 40% of the one-repetition-maximum for the lower limbs (e.g., leg press, knee extensions). Before and after training, sprint (20-m sprint), change-of-direction speed (T-agility test), jump (drop, countermovement jump), and balance performances (Y balance test) were assessed. ANCOVA statistics revealed large main effects of group for 20-m sprint velocity and ground contact time (0.81 ≤ d ≤ 1.00). Post-hoc tests showed higher sprint velocity following RST and TPT (0.69 ≤ d ≤ 0.82) when compared to the control group, but no difference between RST and TPT. Pre-to-post changes amounted to 4.5% for RST [90%CI: (−1.1%;10.1%), d = 1.23] and 2.6% for TPT [90%CI: (0.4%;4.8%), d = 1.59]. Additionally, ground contact times during sprinting were shorter following RST and TPT (0.68 ≤ d ≤ 1.09) compared to the control group, but no difference between RST and TPT. Pre-to-post changes amounted to −6.3% for RST [90%CI: (−11.4%;−1.1%), d = 1.45) and −2.7% for TPT [90%CI: (−4.2%;−1.2%), d = 2.36]. Finally, effects for change-of-direction speed, jump, and balance performance varied from small-to-large. The present findings indicate that 6 weeks of RST and TPT produced similar effects on 20-m sprint performance compared with a passive control in healthy and physically active, young adults. However, no training-related effects were found for change-of-direction speed, jump and balance performance. We conclude that both training regimes can be applied for speed development.
Plyometric jump training (PJT) is a frequently used and effective means to improve amateur and elite soccer players' physical fitness. However, it is unresolved how different PJT frequencies per week with equal overall training volume may affect training-induced adaptations. Therefore, the aim of this study was to compare the effects of an in-season 8 week PJT with one session vs. two sessions per week and equal training volume on components of physical fitness in amateur female soccer players. A single-blind randomized controlled trial was conducted. Participants (N = 23; age, 21.4 ± 3.2 years) were randomly assigned to a one session PJT per-week (PJT-1, n = 8), two sessions PJT per-week (PJT-2, n = 8) or an active control group (CON, n = 7). Before and after training, participants performed countermovement jumps (CMJ), drop-jumps from a 20-cm drop-height (DJ20), a maximal kicking velocity test (MKV), the 15-m linear sprint-time test, the Meylan test for the assessment of change of direction ability (CoDA), and the Yo-Yo intermittent recovery endurance test (Yo-YoIR1). Results revealed significant main effects of time for the CMJ, DJ20, MKV, 15-m sprint, CoDA, and the Yo-YoIR1 (all p < 0.001; d = 0.57–0.83). Significant group × time interactions were observed for the CMJ, DJ20, MKV, 15-m sprint, CoDA, and the Yo-YoIR1 (all p < 0.05; d = 0.36–0.51). Post-hoc analyses showed similar improvements for PJT-1 and PJT-2 groups in CMJ (Δ10.6%, d = 0.37; and Δ10.1%, d = 0.51, respectively), DJ20 (Δ12.9%, d = 0.47; and Δ13.1%, d = 0.54, respectively), MKV (Δ8.6%, d = 0.52; and Δ9.1%, d = 0.47, respectively), 15-m sprint (Δ8.3%, d = 2.25; and Δ9.5%, d = 2.67, respectively), CoDA (Δ7.5%, d = 1.68; and Δ7.4%, d = 1.16, respectively), and YoYoIR1 (Δ10.3%, d = 0.22; and Δ9.9%, d = 0.26, respectively). No significant pre-post changes were found for CON (all p > 0.05; Δ0.5–4.2%, d = 0.03–0.2). In conclusion, higher PJT exposure in terms of session frequency has no extra effects on female soccer players' physical fitness development when jump volume is equated during a short-term (i.e., 8 weeks) training program. From this, it follows that one PJT session per week combined with regular soccer-specific training appears to be sufficient to induce physical fitness improvements in amateur female soccer players.
The regular monitoring of physical fitness and sport-specific performance is important in elite sports to increase the likelihood of success in competition. This study aimed to systematically review and to critically appraise the methodological quality, validation data, and feasibility of the sport-specific performance assessment in Olympic combat sports like amateur boxing, fencing, judo, karate, taekwondo, and wrestling. A systematic search was conducted in the electronic databases PubMed, Google-Scholar, and Science-Direct up to October 2017. Studies in combat sports were included that reported validation data (e.g., reliability, validity, sensitivity) of sport-specific tests. Overall, 39 studies were eligible for inclusion in this review. The majority of studies (74%) contained sample sizes <30 subjects. Nearly, 1/3 of the reviewed studies lacked a sufficient description (e.g., anthropometrics, age, expertise level) of the included participants. Seventy-two percent of studies did not sufficiently report inclusion/exclusion criteria of their participants. In 62% of the included studies, the description and/or inclusion of a familiarization session (s) was either incomplete or not existent. Sixty-percent of studies did not report any details about the stability of testing conditions. Approximately half of the studies examined reliability measures of the included sport-specific tests (intraclass correlation coefficient [ICC] = 0.43–1.00). Content validity was addressed in all included studies, criterion validity (only the concurrent aspect of it) in approximately half of the studies with correlation coefficients ranging from r = −0.41 to 0.90. Construct validity was reported in 31% of the included studies and predictive validity in only one. Test sensitivity was addressed in 13% of the included studies. The majority of studies (64%) ignored and/or provided incomplete information on test feasibility and methodological limitations of the sport-specific test. In 28% of the included studies, insufficient information or a complete lack of information was provided in the respective field of the test application. Several methodological gaps exist in studies that used sport-specific performance tests in Olympic combat sports. Additional research should adopt more rigorous validation procedures in the application and description of sport-specific performance tests in Olympic combat sports.
It is well-documented that strength training (ST) improves measures of muscle strength in young athletes. Less is known on transfer effects of ST on proxies of muscle power and the underlying dose-response relationships. The objectives of this meta-analysis were to quantify the effects of ST on lower limb muscle power in young athletes and to provide dose-response relationships for ST modalities such as frequency, intensity, and volume. A systematic literature search of electronic databases identified 895 records. Studies were eligible for inclusion if (i) healthy trained children (girls aged 6–11 y, boys aged 6–13 y) or adolescents (girls aged 12–18 y, boys aged 14–18 y) were examined, (ii) ST was compared with an active control, and (iii) at least one proxy of muscle power [squat jump (SJ) and countermovement jump height (CMJ)] was reported. Weighted mean standardized mean differences (SMDwm) between subjects were calculated. Based on the findings from 15 statistically aggregated studies, ST produced significant but small effects on CMJ height (SMDwm = 0.65; 95% CI 0.34–0.96) and moderate effects on SJ height (SMDwm = 0.80; 95% CI 0.23–1.37). The sub-analyses revealed that the moderating variable expertise level (CMJ height: p = 0.06; SJ height: N/A) did not significantly influence ST-related effects on proxies of muscle power. “Age” and “sex” moderated ST effects on SJ (p = 0.005) and CMJ height (p = 0.03), respectively. With regard to the dose-response relationships, findings from the meta-regression showed that none of the included training modalities predicted ST effects on CMJ height. For SJ height, the meta-regression indicated that the training modality “training duration” significantly predicted the observed gains (p = 0.02), with longer training durations (>8 weeks) showing larger improvements. This meta-analysis clearly proved the general effectiveness of ST on lower-limb muscle power in young athletes, irrespective of the moderating variables. Dose-response analyses revealed that longer training durations (>8 weeks) are more effective to improve SJ height. No such training modalities were found for CMJ height. Thus, there appear to be other training modalities besides the ones that were included in our analyses that may have an effect on SJ and particularly CMJ height. ST monitoring through rating of perceived exertion, movement velocity or force-velocity profile could be promising monitoring tools for lower-limb muscle power development in young athletes.
The purpose of this study was to examine sex-specific effects of different footwear properties vs. barefoot condition during the performance of drop jumps (DJs) on stable and unstable surfaces on measures of jump performance, electromyographic (EMG) activity, and knee joint kinematics. Drop jump performance, EMG activity of lower-extremity muscles, as well as sagittal and frontal knee joint kinematics were tested in 28 healthy male (n = 14) and female (n = 14) physically active sports science students (23 6 2 years) during the performance of DJs on stable and unstable surfaces using different footwear properties (elastic vs. minimal shoes) vs. barefoot condition. Analysis revealed a significantly lower jump height and performance index (Delta 7-12%; p < 0.001; 2.22 <= d = 2.90) during DJs on unstable compared with stable surfaces. This was accompanied by lower thigh/shank muscle activities (Delta 11-28%; p < 0.05; 0.99 <= d = 2.16) and knee flexion angles (Delta 5-8%; p < 0.05; 1.02 <= d = 2.09). Furthermore, knee valgus angles during DJs were significantly lower when wearing shoes compared with barefoot condition (Delta 22-32%; p < 0.01; 1.38 <= d = 3.31). Sex-specific analyses indicated higher knee flexion angles in females compared with males during DJs, irrespective of the examined surface and footwear conditions (Delta 29%; p < 0.05; d = 0.92). Finally, hardly any significant footwear-surface interactions were detected. Our findings revealed that surface instability had an impact on DJ performance, thigh/shank muscle activity, and knee joint kinematics. In addition, the single factors "footwear" and "sex" modulated knee joint kinematics during DJs. However, hardly any significant interaction effects were found. Thus, additional footwear-related effects can be neglected when performing DJs during training on different surfaces.
Combining training of muscle strength and cardiorespiratory fitness within a training cycle could increase athletic performance more than single-mode training. However, the physiological effects produced by each training modality could also interfere with each other, improving athletic performance less than single-mode training. Because anthropometric, physiological, and biomechanical differences between young and adult athletes can affect the responses to exercise training, young athletes might respond differently to concurrent training (CT) compared with adults. Thus, the aim of the present systematic review with meta-analysis was to determine the effects of concurrent strength and endurance training on selected physical fitness components and athletic performance in youth. A systematic literature search of PubMed and Web of Science identified 886 records. The studies included in the analyses examined children (girls age 6-11 years, boys age 6-13 years) or adolescents (girls age 12-18 years, boys age 14-18 years), compared CT with single-mode endurance (ET) or strength training (ST), and reported at least one strength/power-(e.g., jump height), endurance-(e.g., peak. VO2, exercise economy), or performance-related (e.g., time trial) outcome. We calculated weighted standardized mean differences (SMDs). CT compared to ET produced small effects in favor of CT on athletic performance (n = 11 studies, SMD = 0.41, p = 0.04) and trivial effects on cardiorespiratory endurance (n = 4 studies, SMD = 0.04, p = 0.86) and exercise economy (n = 5 studies, SMD = 0.16, p = 0.49) in young athletes. A sub-analysis of chronological age revealed a trend toward larger effects of CT vs. ET on athletic performance in adolescents (SMD = 0.52) compared with children (SMD = 0.17). CT compared with ST had small effects in favor of CT on muscle power (n = 4 studies, SMD = 0.23, p = 0.04). In conclusion, CT is more effective than single-mode ET or ST in improving selected measures of physical fitness and athletic performance in youth. Specifically, CT compared with ET improved athletic performance in children and particularly adolescents. Finally, CT was more effective than ST in improving muscle power in youth.
The regular monitoring of physical fitness and sport-specific performance is important in elite sports to increase the likelihood of success in competition. This study aimed to systematically review and to critically appraise the methodological quality, validation data, and feasibility of the sport-specific performance assessment in Olympic combat sports like amateur boxing, fencing, judo, karate, taekwondo, and wrestling. A systematic search was conducted in the electronic databases PubMed, Google-Scholar, and Science-Direct up to October 2017. Studies in combat sports were included that reported validation data (e.g., reliability, validity, sensitivity) of sport-specific tests. Overall, 39 studies were eligible for inclusion in this review. The majority of studies (74%) contained sample sizes <30 subjects. Nearly, 1/3 of the reviewed studies lacked a sufficient description (e.g., anthropometrics, age, expertise level) of the included participants. Seventy-two percent of studies did not sufficiently report inclusion/exclusion criteria of their participants. In 62% of the included studies, the description and/or inclusion of a familiarization session (s) was either incomplete or not existent. Sixty-percent of studies did not report any details about the stability of testing conditions. Approximately half of the studies examined reliability measures of the included sport-specific tests (intraclass correlation coefficient [ICC] = 0.43–1.00). Content validity was addressed in all included studies, criterion validity (only the concurrent aspect of it) in approximately half of the studies with correlation coefficients ranging from r = −0.41 to 0.90. Construct validity was reported in 31% of the included studies and predictive validity in only one. Test sensitivity was addressed in 13% of the included studies. The majority of studies (64%) ignored and/or provided incomplete information on test feasibility and methodological limitations of the sport-specific test. In 28% of the included studies, insufficient information or a complete lack of information was provided in the respective field of the test application. Several methodological gaps exist in studies that used sport-specific performance tests in Olympic combat sports. Additional research should adopt more rigorous validation procedures in the application and description of sport-specific performance tests in Olympic combat sports.