Background: Stability is one of the key demands in human locomotion including running. Various kinematical analytical approaches are adopted to investigate the running strategies; nevertheless, the impacts of running speeds on the variability of angles in individual lower limbs joints is still unclear. Objective: This study was aimed to investigate the impact of various running speeds on linear and non-linear variability of the hip, knee and ankle joints movement. Methods: Twenty-three collegiate athletes (13 females, 10 males, age 22.04 ± 3.43 years, body mass 62.14 ± 9.26 kg, height 168.29 ± 7.06 cm) ran at preferred running speed, 20% lower, and 20% higher than preferred running speed on a treadmill and their lower limbs joints kinematics were recorded using myoMOTION system at the sampling frequency of 200 Hz. The repeated measure analysis of variance test was adopted to investigate the linear (mean and standard deviation) and non-linear (Lyapunov exponent) variability of the hip, knee and ankle angle in sagittal, frontal and transverse planes throughout the running cycle. Results: No significant difference was observed between the lower limbs joint angles variability in linear analysis, while the Lyapunov exponent of the hip (p = .008, ηp2 = .338), knee (p = .002, ηp2 = .249) joints in the sagittal plane significantly increased as running speed increased. Conclusions: Findings of this study revealed that the hip and knee joints respond with more freedom of movement in the sagittal plane while walking speed increases, although nonlinear approaches were the only ones capable of detecting it. Given that speed changes might reduce body stability, it appears that these joints are attempting to maintain body stability by regulating internal body system perturbations by increasing their variability.

• Klíčová slova
• Lyapunův exponent,
• MeSH
• běh * fyziologie   MeSH
• biomechanika MeSH
• lidé MeSH
• výzkum MeSH
• Check Tag
• lidé MeSH

BACKGROUND: Adaptation of the walking pattern to uphill walking demands immediate coordination between the lower limb segments. Nonetheless, knowledge about individual joints' responses and variability in response to the new slope angles are missing. AIMS: This study investigated the impacts of uphill walking on the ankle, the knee and the hip joints angles and their variability. METHODS: Twenty-three collegiate athletes (age: 22.04 ± 3.43years, body mass: 62.14 ± 9.26Kg, height: 168.29 ± 7.06 cm) walked on an inclined treadmill at 0 ° (level walking -LW), 5 ° (low-slope-walking -LSW), and 10 ° (high-slope-walking -HSW) slopes at their preferred walking speed (4.2 ± 0.51 km.h-1). The ankle, knee and hip joints angles and their variability (standard deviations) were calculated and analysed throughout the gait cycles in LW, LSW, and HSW. RESULTS: Repeated measure ANOVA portrayed significant differences between the ankle joint angles in sagittal (p < .001, ηp2>.14), frontal (p < .05, ηp2>.14), and transverse (p < .005, .14 < ηp2>.01) planes. In the knee joint, the sagittal (p < .001, ηp2>.14), frontal (p < .05, ηp2>.14), and transverse (p < .05, ηp2>.14) angles were significantly different (p < 0.05). Similarly, in the hip joint, the sagittal (p < .05, ηp2>.14), frontal (p < .05, ηp2>.14), and transverse (p < .05, ηp2>.14) angles were significantly different. Ankle angle variability was significantly different in sagittal (P < .001, ηp2>.14), frontal (p = .002, ηp2>.14) and horizontal (P < .001, ηp2>.14) planes, as well as knee joint angle variability in sagittal, frontal and horizontal planes p < 0.001, ηp2>.14. The hip joint variability was considerably different in sagittal (p = .031, ηp2>.14) and horizontal (p < .05, ηp2>.14) planes. CONCLUSION: Uphill walking involves further modifications in the ankle, knee and hip joints angle to adjust the whole-body movements to a new slope. This adjustment resulted in a firm base of support, provided by the ankle, to regulate the knee and hip joints modifications. Nevertheless, it caused less ankle movement variability and could end up with injuries over long-term uphill walking.

• MeSH
• biomechanika MeSH
• chůze (způsob) * MeSH
• chůze * MeSH
• dolní končetina MeSH
• dospělí MeSH
• hlezenní kloub MeSH
• kolenní kloub MeSH
• kyčelní kloub MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Recently, the use of treadmills for walking and running has increased due to lifestyle changes. However, biomechanical differences in coordination between running on a treadmill or overground have not been adequately addressed. RESEARCH QUESTION: The purpose of this study was to compare coordination and its variability in lower limb segments during treadmill and overground running at different speeds. METHODS: Twenty physically active university undergraduate students participated in this study. Each participant ran trials for both overground and treadmill running at slow and fast speeds. Three-dimensional kinematic data of the lower limb segments were captured. The continuous relative phase (CRP) was used to compute coordination and its variability (VCRP) for foot, shank, and thigh segments of the dominant side of the participants. RESULTS: A vector analysis using statistical parametric mapping (SPM) revealed that there were statistically significant differences in the calculated CRPs for treadmill and overground running in the stance phase of running and for different running speeds in the late stance and swing phases. However, the VCRPs calculated for the two locations and speeds did not exhibit any statistically significant differences. CONCLUSION: The findings of this study suggest differences in segment coupling between treadmill and overground running may affect lower extremity biomechanics. In addition, changes in the coupling patterns for different running speeds suggest that segment coordination is not stable in the range of training speeds used by runners. Finally, the lack of differences in the variability of segment couplings during treadmill and overground conditions at different speeds potentially demonstrates similar dynamic neuromuscular control and degrees of freedom at these different running locations and speeds.

• MeSH
• běh fyziologie   MeSH
• biomechanika MeSH
• dolní končetina fyziologie   MeSH
• lidé MeSH
• mladý dospělý MeSH
• studenti MeSH
• univerzity MeSH
• zátěžový test MeSH
• Check Tag
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH