This study was aimed to analyse the lower limb kinematics during the change of direction (COD) performance with the dominant (DL) and non-dominant (NDL) leg using linear (traditional kinematics) and nonlinear (Self Organising Map-based cluster analysis) approaches. Three 5-0-5 COD performances with the DL and three with the NDL were performed by 23 (aged 21.6 ± 2.3 years) collegiate athletes. No significant difference was observed between the COD duration, and approach speed of DL and NDL. Significantly greater ankle abductions, knee and hip external rotations were identified in COD with DL, compared to NDL (p < .001, d > 0.8). Self Organising Maps portrayed a completely different coordination pattern profile during change of direction performance with the DL and NDL. The cluster analysis illustrated similar inter-individual coordination patterning when participants turned with their DL or NDL. No visible relationship was observed in the cluster analysis of the lower limb joint angles and angular velocities. Outcomes of this study portrayed that coordination patterning (combination of joint angles and the rate of change of angles) could portray the movement patterning differences in different tasks, while a sole investigation on the joint angles or angular velocities may not reveal the underlying mechanisms of movement patterning.
- MeSH
- bérec * fyziologie MeSH
- biomechanika MeSH
- dolní končetina * fyziologie MeSH
- funkční lateralita * fyziologie MeSH
- kotník fyziologie MeSH
- lidé MeSH
- mladý dospělý MeSH
- motorické dovednosti * fyziologie MeSH
- nelineární dynamika MeSH
- pohyb fyziologie MeSH
- shluková analýza MeSH
- sportovní výkon * fyziologie MeSH
- Check Tag
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Understanding the intricacies of human movement coordination and variability during running is crucial to unraveling the dynamics of locomotion, identifying potential injury mechanisms and understanding skill development. Identification of minimum number of cycles for calculation of reliable coordination and its variability could help with better test organization and efficient assessment time. By adopting a cross-sectional study design, this study investigated the minimum required cycles for calculating hip-knee, hip-ankle and knee-ankle coordination and their variability using a continuous relative phase (CRP) method. Twenty-nine healthy adults ran on a treadmill at speeds of 9, 12.5, and 16 km.h-1 while 3D kinematic data of their lower limbs were recorded using 6 optoelectronic cameras. Using Intraclass Correlation Coefficient (ICC) analysis, reliability between CRP and its variability (CRPv) in different gait cycles (3, 5, 10, 20, 30) was assessed for each speed. A minimum of 10 cycles was required for CRP calculation across all speeds, whereas CRPv necessitated a minimum of 30 cycles for moderate to good reliability. While increasing the number of cycles improved ICC values for inter-joint CRP, the same trend was not consistently observed for CRPv, emphasizing the importance of separately assessing CRP and its variability metrics.
- MeSH
- běh * fyziologie MeSH
- biomechanika MeSH
- chůze (způsob) * fyziologie MeSH
- dospělí MeSH
- hlezenní kloub * fyziologie MeSH
- kolenní kloub * fyziologie MeSH
- kyčelní kloub fyziologie MeSH
- lidé MeSH
- mladý dospělý MeSH
- průřezové studie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
OBJECTIVES: This study aimed to investigate the impact of SportsMetrics programs on knee and ankle kinematics, as well as knee-ankle coupling responses during double leg landings among female athletes with dynamic knee valgus (ligament dominance). METHODS: Eighty-four female athletes, including 30 volleyball players, 30 basketball players, and 24 soccer players, were randomly divided into two equal training (TG) and a control groups (CG). The TG underwent 18 sessions of SportsMetrics exercises, while the CG maintained their regular exercise routine. Dynamic knee valgus, lower limb kinematics, and coordination were assessed using the double leg squat and landing error scoring system tests. MAIN OUTCOME MEASURES: The main outcome measures encompassed knee sagittal and frontal kinematics, ankle sagittal kinematics, as well as knee-ankle coordination and its variability. RESULTS: Significant reduction in knee range of motion in the frontal plane was observed across all three sports during landing. The SportsMetrics program tailored for basketball players led to a specific increase in knee flexion. CONCLUSION: The implementation of SportsMetrics effectively modifies ACL injury risk factors, addressing dynamic knee valgus and landing techniques in female athletes. Female athletes displaying dynamic knee valgus are advised to incorporate sport-specific SportsMetrics programs into their training regimens for optimal results.
- MeSH
- basketbal fyziologie MeSH
- biomechanika fyziologie MeSH
- dospělí MeSH
- fotbal fyziologie MeSH
- hlezenní kloub * fyziologie MeSH
- kolenní kloub * fyziologie MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- poranění předního zkříženého vazu patofyziologie MeSH
- rozsah kloubních pohybů * fyziologie MeSH
- sportovci MeSH
- volejbal fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- randomizované kontrolované studie MeSH
The aim of this study was to examine the effect of attentional focus instructions on the biomechanical variables associated with the risk of anterior cruciate ligament injury of the knee joint during a drop landing task using a time series analysis. Ten female volleyball players (age: 20.4 ± 0.8 years, height: 169.7 ± 7.1 cm, mass: 57.6 ± 3.1 kg, experience: 6.3 ± 0.8 years) performed landings from a 50 cm height under three different attentional focus conditions: (1) external focus (focus on landing as soft as possible), (2) internal focus (focus on bending your knees when you land), and (3) control (no-focus instruction). Statistical parameter mapping in the sagittal plane during the crucial first 30% of landing time showed a significant effect of attentional focus instructions. Despite the similarity in landing performance across foci instructions, adopting an external focus instruction promoted reduced vertical ground reaction force and lower sagittal flexion moment during the first 30% of execution time compared to internal focus, suggesting reduced knee loading. Therefore, adopting an external focus of attention was suggested to reduce most biomechanical risk variables in the sagittal plane associated with anterior cruciate ligament injuries, compared to internal focus and control condition. No significant differences were found in the frontal and horizontal planes between the conditions during this crucial interval.
- MeSH
- biomechanika fyziologie MeSH
- kolenní kloub * fyziologie MeSH
- lidé MeSH
- mladý dospělý MeSH
- poranění předního zkříženého vazu patofyziologie MeSH
- pozornost * fyziologie MeSH
- volejbal * fyziologie MeSH
- Check Tag
- lidé MeSH
- mladý dospělý MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: To prevent the risk of stair descent falls and associated injuries in the older adults, it is important to understand the factors that affect this frequent locomotion of daily living. The fact that falls are in most cases the result of the interaction between intrinsic and extrinsic factors is very often underestimated when designing test protocols. RESEARCH QUESTION: This study aimed at evaluating balance control during and immediately after step down onto an unstable surface. METHODS: Physically active men and women aged 60-69 years (n = 28) and 70-79 years (n = 18) were asked to perform a step down onto a foam pad and stand still for 30 s (restabilization phase). Centre of pressure (CoP) velocity and standard deviation of CoP sway in anteroposterior and mediolateral direction were evaluated during the step down (CoP VAP, CoP VML, CoP SDAP, CoP SDML) and in the first 5 s of restabilization (CoP VAP5, CoP VML5, CoP SDAP5, CoP SDML5). In addition, time to complete step was investigated. RESULTS: Participants aged 70-79 years presented worse ML balance control after step down onto an unstable surface than their younger counterparts. This was represented by the significantly higher values of CoP SDML5 and CoP VML5 (p = 0.022 and p = 0.017). No other significant differences were detected. SIGNIFICANCE: Age is associated with a more significant ML center of pressure velocity and sway after step down onto a foam pad in physically active older adults. Exercises aimed at improving ML balance control in unstable conditions should be the subject of physical interventions even in older adults with overall good state of health and physical fitness.
- MeSH
- cvičení * MeSH
- fyzikální vyšetření MeSH
- lidé MeSH
- lokomoce MeSH
- posturální rovnováha * MeSH
- senioři MeSH
- terapie cvičením MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
As predictive motor control is an important index of neuromotor development and maturation, we developed two touchscreen tablet-based tests of this function. Our aim was to investigate the reliability and validity of both a rapid manual interception test and a pursuit tracking test, using a sample of 124 children (62 boys and 62 girls) from two age groups (7-8-year-oldss and 9-10-year-olds). Participants performed both tablet tests with a stylus (sample rate 100 Hz) with both a visible and a temporarily invisible moving target. Confirmatory factor analyses and omega coefficients showed that both tests were univariate methods that provided a reliable assessment of the latent factor related to predictive visuomotor control. As would be expected, compared to younger children, older children performed better on both manual interception and pursuit tracking. The correlations between the latent factors of the two tests at 95% confidence intervals (-.276, -.608) suggested shared variance. Thus, the touchscreen-tablet based tests of rapid manual interception and manual pursuit tracking appear psychometrically suitable for assessing the neuromotor ability of predictive control in 7-10-year-old children.
- MeSH
- dítě MeSH
- faktorová analýza statistická MeSH
- lidé MeSH
- mladiství MeSH
- reprodukovatelnost výsledků * MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
INTRO: The purpose of this study was to investigate the effects of quiet eye training (QET) on inhibitory control, visuospatial working memory (WM), and tonic attention in children with attention-deficit hyperactivity disorder (ADHD). METHODS: Forty-eight children with ADHD aged 9-12 years were randomly assigned to QET and control (CON) groups. The QET group practiced targeted hand-eye tasks within a QET protocol developed to optimize controlled attention and gaze through eye fixations. We used the go/no-go (GNG) test, the Corsi test, and the reaction test of alertness (RTA) to verify the effects of QET on inhibition control, WM, and tonic attention. RESULTS: QET group showed significantly shorter reaction times, a higher number of correct responses, and a lower number of omissions in the GNG inhibition test after QET as compared to the pre-measurements, whereas the CON group did not demonstrate significant changes in this test. The measures of WM (Corsi test) and tonic attention (RTA) did not change significantly with the QET-based intervention. CONCLUSION: The study demonstrated that the QET protocol, which includes instructions and a video demonstration to optimize eye fixation on a target during aiming tasks, is acceptable and usable for children with ADHD. Overall, a short-term, 5-week visuomotor training intervention based on the quiet eye paradigm was shown to be effective in improving inhibitory control and focused visual attention, but not visuospatial WM and intrinsic attention in 9-12-year-old children with inattentive or combined ADHD.
- MeSH
- dítě MeSH
- dvojitá slepá metoda MeSH
- hyperkinetická porucha * terapie MeSH
- kognice MeSH
- krátkodobá paměť * fyziologie MeSH
- lidé MeSH
- oční fixace MeSH
- reakční čas MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- randomizované kontrolované studie MeSH
Task and environment-related constraints can influence spike performance in volleyball players. This study was designated to investigate the impact of awareness of the presence or absence of a defensive block by the opponents on the performance and coordination pattern of spikes in elite volleyball attackers. Simulating a real-game scenario, 10 elite youth attackers (aged 15.5 ± 0.7 years) executed six spikes each with prior notification about the presence/absence of defences and six spikes without any notification. In each condition, they were blocked by two opponents in three trials. The coordination patterning of the attackers was explored using cluster analysis based on a Self-Organising Map (SOM). The SOMs and the cluster analysis showed that the coordination pattern of the spike execution was very individual-specific; however, in the third layer of the cluster analysis, it was revealed that the movement pattern of spike execution had similarities in the scenario wherein the players had prior awareness of the defences. Providing the attackers with information on the opponents' condition or performance could shift the attackers' focus from a game-oriented condition to the rivals' behaviour, which consequently resulted in deterioration of their spike performance.
- MeSH
- biomechanika MeSH
- lidé MeSH
- mladiství MeSH
- sportovní výkon * MeSH
- volejbal * MeSH
- Check Tag
- lidé MeSH
- mladiství MeSH
- Publikační typ
- časopisecké články MeSH
This study aimed to compare the angle-specific (AS) and non-angle-specific (NAS) hamstring to quadriceps conventional and functional ratios between healthy, hamstring- and ACL-injured elite soccer players. One hundred and eleven players (27.42 ± 8.01 years, 182.11 ± 6.79 cm, 75.93 ± 7.25 kg) completed a series of concentric knee flexor and extensor strength in addition to eccentric knee flexor strength was measured at an angular velocity of 60°.s-1. Normalized and raw peak torque values, and the torque-angle profiles were extracted for analysis. Conventional and functional NAS (peak values) and AS (waveform ratios) hamstring to quadriceps ratios were calculated and compared between the groups. Healthy players produced greater functional and conventional ratios compared to players with either ACL or hamstring injury. Players with hamstring injury produced a lower AS functional ratios between 46° and 54° of knee flexion. Players suffering from ACL injury depicted a lower value for the AS functional ratio between 33° and 56° of knee flexion. Although NAS can identify soccer players with previous hamstring or ACL injury, the range where there is a strength deficiency is eluded. With the use of AS the range where the deficiency is present can be identified, and clinicians can benefit from this analysis to design robust rehabilitation protocols.
Mobile phone use affects the dynamics of gait by impairing visual control of the surrounding environment and introducing additional cognitive demands. Although it has been shown that using a mobile phone alters whole-body dynamic stability, no clear information exists on its impacts on motor variability during gait. This study aimed at assessing the impacts of various types of mobile phone use on motor variability during gait; quantified using the short- and long-term Lyapunov Exponent (λS and λL) of lower limb joint angles and muscle activation patterns, as well as the centre of mass position. Fourteen females and Fifteen males (27.72 ± 4.61 years, body mass: 70.24 ± 14.13 Kg, height: 173.31 ± 10.97 cm) walked on a treadmill under six conditions: normal walking, normal walking in low-light, walking while looking at the phone, walking while looking at the phone in low-light, walking and talking on the phone, and walking and listening to music. Variability of the hip (p λS = .015, λL = .043) and pelvis (p λS = .039, λL = .017) joint sagittal angles significantly increased when the participants walked and looked at the phone, either in normal or in low-light conditions. No significant difference was observed in the variability of the centre of mass position and muscle activation patterns. When individuals walk and look at the phone screen, the hip and knee joints are constantly trying to adopt a new angle to regulate and maintain gait stability, which might put an additional strain on the neuromuscular system. To this end, it is recommended not to look at the mobile phone screen while walking, particularly in public places with higher risks of falls.
