Refine
Has Fulltext
- no (177)
Year of publication
Document Type
- Article (177) (remove)
Is part of the Bibliography
- yes (177)
Keywords
- football (15)
- athletic performance (11)
- balance (10)
- youth (10)
- adolescents (9)
- resistance training (9)
- stretch-shortening cycle (9)
- strength training (8)
- electromyography (7)
- training (7)
- Exercise (6)
- Gait (6)
- children (6)
- exercise (6)
- monitoring (6)
- performance (6)
- postural control (6)
- strength (6)
- training load (6)
- young athletes (6)
- Electromyography (5)
- Stretch-shortening cycle (5)
- injury risk (5)
- power (5)
- EMG (4)
- Ground reaction force (4)
- Resistance training (4)
- aging (4)
- elite athletes (4)
- gait (4)
- periodization (4)
- Aging (3)
- Balance (3)
- Seniors (3)
- Walking (3)
- agility (3)
- change of direction (3)
- force (3)
- ground reaction force (3)
- injury (3)
- jumping (3)
- loading rate (3)
- movement (3)
- muscle strength (3)
- physiology (3)
- plyometric training (3)
- postural stability (3)
- soccer (3)
- speed (3)
- sport-specific performance (3)
- striking combat sports (3)
- working memory (3)
- Body composition (2)
- COVID-19 (2)
- Cognitive/motor interference (2)
- Detraining (2)
- EEG (2)
- Jump height (2)
- Kampfsport (2)
- Muscle strength (2)
- Performance (2)
- Postural stability (2)
- Proactive/reactive balance (2)
- Single/dual tasking (2)
- Steady-state balance (2)
- Team sports (2)
- Trunk muscle strength (2)
- Youth (2)
- attentional demand (2)
- biomechanics (2)
- cognitive performance (2)
- cognitive-postural dual task (2)
- combat sport (2)
- cross-education (2)
- drop jump (2)
- fatigue (2)
- gait analysis (2)
- global positioning system (2)
- ground reaction forces (2)
- hospitalization (2)
- human physical conditioning (2)
- inertial measurement unit (2)
- jumps (2)
- knee joint angle (2)
- maturity (2)
- modality compatibility (2)
- motor skills (2)
- muscle (2)
- muscle power (2)
- musculoskeletal and neural physiological phenomena (2)
- oarsmen (2)
- on-water performance (2)
- peak height velocity (2)
- physical fitness (2)
- physical performance (2)
- plyometric exercise (2)
- plyometrics (2)
- postural sway (2)
- range of motion (2)
- rate of perceived exertion (2)
- rate of torque development (2)
- recovery (2)
- reliability (2)
- rolling averages (2)
- running (2)
- running mechanics (2)
- sensitivity (2)
- somatic variables (2)
- sportliche Leistung (2)
- sprint (2)
- sprints (2)
- talent (2)
- validity (2)
- weighted moving averages (2)
- youth athletes (2)
- youth soccer (2)
- youth sports (2)
- ACWR (1)
- Acceleration (1)
- Acute Recovery and Stress Scale (ARSS) (1)
- Alpha-2 (1)
- Association (1)
- Attention (1)
- Balance Tests (1)
- Biomechanics (1)
- Bow leg (1)
- Central activation (1)
- Children (1)
- Cognition motor (1)
- Cognitive enhancer (1)
- Cognitive fatigue (1)
- Cognitive interference (1)
- Cognitive skills (1)
- Computer Software (1)
- Conditioning activity (1)
- Core stability (1)
- Core strength (1)
- Countermovement jump (1)
- Cross-over fatigue (1)
- Crossover (1)
- Crossover fatigue (1)
- DXA (1)
- Daily life (1)
- Dual tasks (1)
- EXERCISE (1)
- Elderly (1)
- Electric stimulation (1)
- Electroencephalography (EEG) (1)
- Electromyography (EMG) (1)
- Elite sports (1)
- Endurance (1)
- Executive function (1)
- Exercise therapy (1)
- Exertion (1)
- Exhaustion (1)
- Explosive force production (1)
- Fall risk (1)
- Fall risk assessment (1)
- Falls (1)
- Fatigue (1)
- Flat feet (1)
- Football (1)
- Footwear (1)
- Force production (1)
- Frail elderly (1)
- Free moment (1)
- Functional magnetic resonance imaging (fMRI) (1)
- Gait kinematics (1)
- Gait kinetics (1)
- Ginkgo biloba extract (1)
- Gym-based/home-based training (1)
- Healthy aging (1)
- ICA (1)
- Injury risk (1)
- Instability (1)
- Intensity Dose -response relationship (1)
- Isokinetic (1)
- Judo-specific pulling movement (1)
- Jugendliche (1)
- Jumping height (1)
- Kinder (1)
- Kindergarten (1)
- Kinematics (1)
- Knee valgus (1)
- Knee valgus motion (1)
- Lateral jumps (1)
- Linear regression analysis (1)
- Loading rate (1)
- MUSCLE (1)
- Maturation (1)
- Maximal isometric force (1)
- Maximal voluntary contraction (MVC) (1)
- Maximalkraft (1)
- Mild cognitive impairment (1)
- Mobility (1)
- Morote-seoi-nage (1)
- Motion (1)
- Motor function (1)
- Motor performance (1)
- Motor skills (1)
- Movement velocity (1)
- Multiple sclerosis (1)
- Muscle (1)
- Muscle contraction (1)
- Muscle mass (1)
- Muscle power (1)
- Muscle torque (1)
- Oberflächenelektromyografie (1)
- OptoGait (1)
- Optojump system (1)
- Overhead athletes (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)
- Postural control (1)
- Power (1)
- Preventive therapy (1)
- Primary school (1)
- Principal component analysis (1)
- Quadriceps muscle (1)
- Quadriceps strength (1)
- Quarantine (1)
- RGB-D cameras (1)
- RPE (1)
- Reactive movement (1)
- Recovery (1)
- Repeated sprint (1)
- Scanning electron microscopy (1)
- Schnellkraft (1)
- Sensorimotor training (1)
- Short‐term effect (1)
- Shoulder (1)
- Speed (1)
- Sport-specific performance (1)
- Stress (1)
- Stress levels (1)
- Sway (1)
- Swimming performance (1)
- Theraband training (1)
- Theta (1)
- Tiredness (1)
- Transcranial magnetic brain stimulation (TMS) (1)
- Velocity (1)
- Vertec device (1)
- WALKING (1)
- Walking speed (1)
- Widerstandstraining (1)
- Work ability (1)
- Young swimmers (1)
- Zebris (1)
- academy (1)
- acute chronic workload ratio (1)
- adolescent (1)
- adolescent athletes (1)
- aerobic metabolism (1)
- aerobic power (1)
- age (1)
- allometry (1)
- alpha-2 (1)
- ankles (1)
- annual training (1)
- anterior cruciate ligament (1)
- anthropometry (1)
- anxiety (1)
- apoptosis (1)
- assessment (1)
- athlete testing (1)
- athlete. (1)
- athletes (1)
- athletic (1)
- attention (1)
- balance strategy (1)
- balance training (1)
- ball speed (1)
- ballistic training (1)
- barbell velocity (1)
- biological age (1)
- biological maturation (1)
- blood (1)
- blood sample (1)
- body density (1)
- body limbs (1)
- body shape (1)
- bone (1)
- calcaneal eversion (1)
- canoe racing (1)
- cardiomyopathy (1)
- cardiorespiratory fitness (1)
- causal mediation analysis (1)
- change of direction speed (1)
- change-of-direction speed (1)
- child (1)
- climbing (1)
- cognitive interference (1)
- cognitive skills (1)
- cognitive/muscular fatigue (1)
- combat sports (1)
- comparison of devices (1)
- concurrent training (1)
- conditioning activity (1)
- conditioning exercise (1)
- conditioning stimulus (1)
- core (1)
- core strength (1)
- data pipeline (1)
- deconditioning (1)
- depression (1)
- detraining (1)
- diabetes (1)
- diabetes mellitus (1)
- diabetic (1)
- digital health (1)
- directed acyclic graphs (1)
- dominant limb (1)
- dose-response relationship (1)
- dual task (1)
- dual-task costs (1)
- early sport specialization (1)
- eccentric-plyometric (1)
- elderly (1)
- electroencephalography (1)
- elite (1)
- endurance (1)
- endurance performance (1)
- energetic systems (1)
- evaluation (1)
- exercise intervention (1)
- exercise test (1)
- exercise training (1)
- exhaustion (1)
- explosive force production (1)
- external load (1)
- external training load (1)
- eyedness (1)
- fMRI (1)
- feet (1)
- field test (1)
- fitness (1)
- fitness tests (1)
- flat feet (1)
- flat foot (1)
- flexibility (1)
- footedness (1)
- footwear (1)
- free moment (1)
- function (1)
- functional performance (1)
- gait analysis algorithm (1)
- gait speed (1)
- gender (1)
- gender differences (1)
- hamstring muscles (1)
- hearing loss (1)
- heart rate (1)
- hematocrit (1)
- high-intensity interval training (1)
- high-intensity-interval training (1)
- hip (1)
- hormones (1)
- human motion (1)
- immune system (1)
- impact loading (1)
- infection (1)
- intermittent sport (1)
- internal load (1)
- intervention (1)
- jump (1)
- jump height (1)
- jump height/power (1)
- jump performance (1)
- jump performances (1)
- jump training (1)
- jump/sprint exercises (1)
- jumping ability (1)
- kindergarten (1)
- kinetics (1)
- knee (1)
- knee flexion angle (1)
- knee osteoarthritis (1)
- knee valgus angle (1)
- knee valgus motion (1)
- knees (1)
- late childhood (1)
- latency (1)
- laterality (1)
- leg extensors (1)
- limb overuse conditions (1)
- linear sprint (1)
- load carriage (1)
- load-velocity (1)
- long-term (1)
- low-back-pain (1)
- lower limb mechanics (1)
- lower-extremity kinematics (1)
- martial arts (1)
- matched time (1)
- material fatigue (1)
- maturation (1)
- maximal isometric contraction (1)
- maximal isometric torque (1)
- maximum voluntary contraction (1)
- medial longitudinal arch (1)
- mental imagery (1)
- meta-analysis (1)
- methodological quality (1)
- miRNAs (1)
- mitochondrial adaptation (1)
- mobility disability (1)
- motion capture (1)
- motor-performance (1)
- muscle activation (1)
- muscle activity (1)
- muscle coactivation (1)
- muscle fitness (1)
- muscle metabolism (1)
- muscular power (1)
- muscular strength (1)
- musculature (1)
- myofascial (1)
- neuromuscular rolling (1)
- non-dominant limb (1)
- of-direction speed (1)
- optimal load (1)
- overreaching (1)
- overtraining (1)
- oxygen consumption (1)
- passive stretching (1)
- patients (1)
- peak torque (1)
- pelvic alignment (1)
- pervasive healthcare (1)
- physical activity (1)
- physical activity program (1)
- physical conditioning human (1)
- physical fitness expertise (1)
- physiological strain (1)
- postural balance (1)
- power training (1)
- preactivation (1)
- pressure (1)
- prevention (1)
- progression (1)
- proprioception (1)
- public dataset (1)
- race (1)
- race time (1)
- randomized controlled-trial (1)
- rate of force development (1)
- region/point elastic gym floor (1)
- relationship (1)
- relationships (1)
- responses (1)
- return-to-sport (1)
- rotation (1)
- rugby league players (1)
- running velocity (1)
- schedule (1)
- scholastic demands (1)
- school baseball players (1)
- sedentary (1)
- self massage (1)
- self-massage therapy (1)
- self-myofascial release (1)
- sensorimotor training (1)
- sensory input (1)
- sex-differences (1)
- shoe (1)
- short latency response (1)
- shoulder girdle (1)
- shoulder strength (1)
- skeletal joints (1)
- ski jumping (1)
- soccer players (1)
- specific assessment (1)
- specific strength training (1)
- specificity (1)
- spezifisches Krafttraining (1)
- sport profile (1)
- sports (1)
- sprinting (1)
- stability (1)
- standing position (1)
- static/dynamic postural control (1)
- stroke (1)
- structured (1)
- surface electromyography (1)
- taekwondo electronic scoring system (1)
- taekwondo-specific testing (1)
- task difficulty (1)
- tasks (1)
- team sport (1)
- tendon stiffness (1)
- test-retest reliability (1)
- therapy (1)
- theta (1)
- time (1)
- time-efficient exercise (1)
- torque (1)
- track and field (1)
- training adaptation (1)
- training intensity (1)
- training specificity (1)
- twitch torque (1)
- unstable walkway (1)
- vertical jump height (1)
- vestibular (1)
- virus (1)
- virus infection (1)
- water sports (1)
- weight loss (1)
- weight training (1)
- weightlifting (1)
- whole-body vibratoin (1)
- women (1)
- work (1)
- young (1)
- young adults (1)
- young soccer players (1)
- youth sport (1)
Institute
Purpose
The objective of the investigation was to determine the concomitant effects of upper arm blood flow restriction (BFR) and inversion on elbow flexors neuromuscular responses.
Methods
Randomly allocated, 13 volunteers performed four conditions in a within-subject design: rest (control, 1-min upright position without BFR), control (1-min upright with BFR), 1-min inverted (without BFR), and 1-min inverted with BFR. Evoked and voluntary contractile properties, before, during and after a 30-s maximum voluntary contraction (MVC) exercise intervention were examined as well as pain scale.
Results
Inversion induced significant pre-exercise intervention decreases in elbow flexors MVC (21.1%, Z2p = 0.48, p = 0.02) and resting evoked twitch forces (29.4%, Z2p = 0.34, p = 0.03). The 30-s MVC induced significantly greater pre- to post-test decreases in potentiated twitch force (Z2p = 0.61, p = 0.0009) during inversion (75%) than upright (65.3%) conditions. Overall, BFR decreased MVC force 4.8% (Z2p = 0.37, p = 0.05). For upright position, BFR induced 21.0% reductions in M-wave amplitude (Z2p = 0.44, p = 0.04). There were no significant differences for electromyographic activity or voluntary activation as measured with the interpolated twitch technique. For all conditions, there was a significant increase in pain scale between the 40-60 s intervals and post-30-s MVC (upright< inversion, and without BFR< BFR).
Conclusion
The concomitant application of inversion with elbow flexors BFR only amplified neuromuscular performance impairments to a small degree. Individuals who execute forceful contractions when inverted or with BFR should be cognizant that force output may be impaired.
Gait analysis is an important tool for the early detection of neurological diseases and for the assessment of risk of falling in elderly people. The availability of low-cost camera hardware on the market today and recent advances in Machine Learning enable a wide range of clinical and health-related applications, such as patient monitoring or exercise recognition at home. In this study, we evaluated the motion tracking performance of the latest generation of the Microsoft Kinect camera, Azure Kinect, compared to its predecessor Kinect v2 in terms of treadmill walking using a gold standard Vicon multi-camera motion capturing system and the 39 marker Plug-in Gait model. Five young and healthy subjects walked on a treadmill at three different velocities while data were recorded simultaneously with all three camera systems. An easy-to-administer camera calibration method developed here was used to spatially align the 3D skeleton data from both Kinect cameras and the Vicon system. With this calibration, the spatial agreement of joint positions between the two Kinect cameras and the reference system was evaluated. In addition, we compared the accuracy of certain spatio-temporal gait parameters, i.e., step length, step time, step width, and stride time calculated from the Kinect data, with the gold standard system. Our results showed that the improved hardware and the motion tracking algorithm of the Azure Kinect camera led to a significantly higher accuracy of the spatial gait parameters than the predecessor Kinect v2, while no significant differences were found between the temporal parameters. Furthermore, we explain in detail how this experimental setup could be used to continuously monitor the progress during gait rehabilitation in older people.
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.
This study aimed to investigate the relationship between the acute to chronic workload ratio (ACWR), based upon participant session rating of perceived exertion (sRPE), using two models [(1) rolling averages (ACWRRA); and (2) exponentially weighted moving averages (ACWREWMA)] and the injury rate in young male team soccer players aged 17.1 ± 0.7 years during a competitive mesocycle. Twenty-two players were enrolled in this study and performed four training sessions per week with 2 days of recovery and 1 match day per week. During each training session and each weekly match, training time and sRPE were recorded. In addition, training impulse (TRIMP), monotony, and strain were subsequently calculated. The rate of injury was recorded for each soccer player over a period of 4 weeks (i.e., 28 days) using a daily questionnaire. The results showed that over the course of the study, the number of non-contact injuries was significantly higher than that for contact injuries (2.5 vs. 0.5, p = 0.01). There were also significant positive correlations between sRPE and training time (r = 0.411, p = 0.039), ACWRRA (r = 0.47, p = 0.049), and ACWREWMA (r = 0.51, p = 0.038). In addition, small-to-medium correlations were detected between ACWR and non-contact injury occurrence (ACWRRA, r = 0.31, p = 0.05; ACWREWMA, r = 0.53, p = 0.03). Explained variance (r²) for non-contact injury was significantly greater using the ACWREWMA model (ranging between 21 and 52%) compared with ACWRRA (ranging between 17 and 39%). In conclusion, the results of this study showed that the ACWREWMA model is more sensitive than ACWRRA to identify non-contact injury occurrence in male team soccer players during a short period in the competitive season.
This study aimed to investigate the relationship between the acute to chronic workload ratio (ACWR), based upon participant session rating of perceived exertion (sRPE), using two models [(1) rolling averages (ACWRRA); and (2) exponentially weighted moving averages (ACWREWMA)] and the injury rate in young male team soccer players aged 17.1 ± 0.7 years during a competitive mesocycle. Twenty-two players were enrolled in this study and performed four training sessions per week with 2 days of recovery and 1 match day per week. During each training session and each weekly match, training time and sRPE were recorded. In addition, training impulse (TRIMP), monotony, and strain were subsequently calculated. The rate of injury was recorded for each soccer player over a period of 4 weeks (i.e., 28 days) using a daily questionnaire. The results showed that over the course of the study, the number of non-contact injuries was significantly higher than that for contact injuries (2.5 vs. 0.5, p = 0.01). There were also significant positive correlations between sRPE and training time (r = 0.411, p = 0.039), ACWRRA (r = 0.47, p = 0.049), and ACWREWMA (r = 0.51, p = 0.038). In addition, small-to-medium correlations were detected between ACWR and non-contact injury occurrence (ACWRRA, r = 0.31, p = 0.05; ACWREWMA, r = 0.53, p = 0.03). Explained variance (r 2) for non-contact injury was significantly greater using the ACWREWMA model (ranging between 21 and 52%) compared with ACWRRA (ranging between 17 and 39%). In conclusion, the results of this study showed that the ACWREWMA model is more sensitive than ACWRRA to identify non-contact injury occurrence in male team soccer players during a short period in the competitive season.
Introduction:
In children, the impact of hearing loss on biomechanical gait parameters is not well understood. Thus, the objectives of this study were to examine three-dimensional lower limb joint torques in deaf compared to age-matched healthy (hearing) children while walking at preferred gait speed.
Methods:
Thirty prepubertal boys aged 8-14 were enrolled in this study and divided into a group with hearing loss (deaf group) and an age-matched healthy control. Three-dimensional joint torques were analyzed during barefoot walking at preferred speed using Kistler force plates and a Vicon motion capture system.
Results:
Findings revealed that boys with hearing loss showed lower joint torques in ankle evertors, knee flexors, abductors and internal rotators as well as in hip internal rotators in both, the dominant and non-dominant lower limbs (all p < 0.05; d = 1.23-7.00; 14-79%). Further, in the dominant limb, larger peak ankle dorsiflexor (p < 0.001; d = 1.83; 129%), knee adductor (p < 0.001; d = 3.20; 800%), and hip adductor torques (p < 0.001; d = 2.62; 350%) were found in deaf participants compared with controls.
Conclusion:
The observed altered lower limb torques during walking are indicative of unstable gait in children with hearing loss. More research is needed to elucidate whether physical training (e.g., balance and/or gait training) has the potential to improve walking performance in this patient group. (C) 2019 Elsevier Ltd. All rights reserved.
Methods: As part of the Potsdam Gait Study (POGS), healthy old adults completed a no-intervention control period (69.1 +/- 4A yrs, n =14) or a power training program followed by detraining (72.9 +/- 5.4 yrs, n = 15).We measured isokinetic knee extensor and plantarflexor power and measured hip, knee and ankle kinetics at habitual, fast and standardized walking speeds. Results: Power training significantly increased isokinetic knee extensor power (25%), plantarflexor power (43%), and fast gait velocity (5.9%). Gait mechanics underlying the improved fast gait velocity included increases in hip angular impulse (29%) and H1 work (37%) and no changes in positive knee (K2) and A2 work. Detraining further improved fast gait velocity (4.7%) with reductions in H1(-35%), and increases in K2 (36%) and A2 (7%). Conclusion: Power training increased fast gait velocity in healthy old adults by increasing the reliance on hip muscle function and thus further strengthened the age-related distal-to-proximal shift in muscle function. (C) 2016 Elsevier B.V. All rights reserved.
Introduction/Purpose: Aging modifies neuromuscular activation of agonist and antagonist muscles during walking. Power training can evoke adaptations in neuromuscular activation that underlie gains in muscle strength and power but it is unknown if these adaptations transfer to dynamic tasks such as walking. We examined the effects of lower-extremity power training on neuromuscular activation during level gait in old adults. Methods: Twelve community-dwelling old adults (age >= 65 yr) completed a 10-wk lower-extremity power training program and 13 old adults completed a 10-wk control period. Before and after the interventions, we measured maximal isometric muscle strength and electromyographic (EMG) activation of the right knee flexor, knee extensor, and plantarflexor muscles on a dynamometer and we measured EMG amplitudes, activation onsets and offsets, and activation duration of the knee flexors, knee extensors, and plantarflexors during gait at habitual, fast, and standardized (1.25 +/- 0.6 m.s(-1)) speeds. Results: Power training-induced increases in EMG amplitude (similar to 41%; 0.47 <= d <= 1.47; P <= 0.05) explained 33% (P = 0.049) of increases in isometric muscle strength (similar to 43%; 0.34 <= d <= 0.80; P <= 0.05). Power training-induced gains in plantarflexor activation during push-off (+11%; d = 0.38; P = 0.045) explained 57% (P = 0.004) of the gains in fast gait velocity (+4%; d = 0.31; P = 0.059). Furthermore, power training increased knee extensor activation (similar to 18%; 0.26 <= d <= 0.29; P <= 0.05) and knee extensor coactivation during the main knee flexor burst (similar to 24%, 0.26 <= d <= 0.44; P <= 0.05) at habitual and fast speed but these adaptations did not correlate with changes in gait velocity. Conclusions: Power training increased neuromuscular activation during isometric contractions and level gait in old adults. The power training-induced neuromuscular adaptations were associated with increases in isometric muscle strength and partly with increases in fast gait velocity.
Background: Walking speed decreases in old age. Even though old adults regularly participate in exercise interventions, we do not know how the intervention-induced changes in physical abilities produce faster walking. The Potsdam Gait Study (POGS) will examine the effects of 10 weeks of power training and detraining on leg muscle power and, for the first time, on complete gait biomechanics, including joint kinematics, kinetics, and muscle activation in old adults with moderate mobility disability. Methods/Design: POGS is a randomized controlled trial with two arms, each crossed over, without blinding. Arm 1 starts with a 10-week control period to assess the reliability of the tests and is then crossed over to complete 25-30 training sessions over 10 weeks. Arm 2 completes 25-30 exercise sessions over 10 weeks, followed by a 10-week follow-up (detraining) period. The exercise program is designed to improve lower extremity muscle power. Main outcome measures are: muscle power, gait speed, and gait biomechanics measured at baseline and after 10 weeks of training and 10 weeks of detraining. Discussion: It is expected that power training will increase leg muscle power measured by the weight lifted and by dynamometry, and these increased abilities become expressed in joint powers measured during gait. Such favorably modified powers will underlie the increase in step length, leading ultimately to a faster walking speed. POGS will increase our basic understanding of the biomechanical mechanisms of how power training improves gait speed in old adults with moderate levels of mobility disabilities. (C) 2016 S. Karger AG, Basel
Cross-education has been extensively investigated with adults. Adult studies report asymmetrical cross-education adaptations predominately after dominant limb training. The objective of the study was to examine unilateral leg press (LP) training of the dominant or nondominant leg on contralateral and ipsilateral strength and balance measures. Forty-two youth (10-13 years) were placed (random allocation) into a dominant (n = 15) or nondominant (n = 14) leg press training group or nontraining control (n = 13). Experimental groups trained 3 times per week for 8 weeks and were tested pre-/post-training for ipsilateral and contralateral 1-repetition maximum (RM) horizontal LP, maximum voluntary isometric contraction (MVIC) of knee extensors (KE) and flexors (KF), countermovement jump (CMJ), triple hop test (THT), MVIC strength of elbow flexors (EF) and handgrip, as well as the stork and Y balance tests. Both dominant and nondominant LP training significantly (p < 0.05) increased both ipsilateral and contralateral lower body strength (LP 1RM (dominant: 59.6%-81.8%; nondominant: 59.5%-96.3%), KE MVIC (dominant: 12.4%-18.3%; nondominant: 8.6%-18.6%), KF MVIC (dominant: 7.9%-22.3%; nondominant: nonsignificant-3.8%), and power (CMJ: dominant: 11.1%-18.1%; nondominant: 7.7%-16.6%)). The exception was that nondominant LP training demonstrated a nonsignificant change with the contralateral KF MVIC. Other significant improvements were with nondominant LP training on ipsilateral EF 1RM (6.2%) and THT (9.6%). There were no significant changes with EF and handgrip MVIC. The contralateral leg stork balance test was impaired following dominant LP training. KF MVIC exhibited the only significant relative post-training to pretraining (post-test/pre-test) ratio differences between dominant versus nondominant LP cross-education training effects. In conclusion, children exhibit symmetrical cross-education or global training adaptations with unilateral training of dominant or nondominant upper leg.