scholarly journals Comparison of Dynamic Knee Valgus During Single-leg Step Down Between People With and Without Pronated Foot Using Two-dimensional Video Analysis

2021 ◽  
Vol 28 (4) ◽  
pp. 266-272
Author(s):  
Hyun-sook Kim ◽  
Hwa-ik Yoo ◽  
Ui-jae Hwang ◽  
Oh-yun Kwon
Keyword(s):  
Video Analysis ◽  
Knee Valgus ◽  
Two Dimensional ◽  
Step Down

scholarly journals CFD Analysis of Urban Canopy Flows Employing the V2F Model: Impact of Different Aspect Ratios and Relative Heights

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Fabio Nardecchia ◽  
Annalisa Di Bernardino ◽  
Francesca Pagliaro ◽  
Paolo Monti ◽  
Giovanni Leuzzi ◽  
...  
Keyword(s):  
Flow Field ◽  
Water Channel ◽  
Flow Regimes ◽  
Two Dimensional ◽  
Mean Flow ◽  
Ansys Fluent ◽  
Practical Applications ◽  
Aspect Ratios ◽  
Starting Point ◽  
Step Down

Computational fluid dynamics (CFD) is currently used in the environmental field to simulate flow and dispersion of pollutants around buildings. However, the closure assumptions of the turbulence usually employed in CFD codes are not always physically based and adequate for all the flow regimes relating to practical applications. The starting point of this work is the performance assessment of the V2F (i.e., v2¯ − f) model implemented in Ansys Fluent for simulating the flow field in an idealized array of two-dimensional canyons. The V2F model has been used in the past to predict low-speed and wall-bounded flows, but it has never been used to simulate airflows in urban street canyons. The numerical results are validated against experimental data collected in the water channel and compared with other turbulence models incorporated in Ansys Fluent (i.e., variations of both k-ε and k-ω models and the Reynolds stress model). The results show that the V2F model provides the best prediction of the flow field for two flow regimes commonly found in urban canopies. The V2F model is also employed to quantify the air-exchange rate (ACH) for a series of two-dimensional building arrangements, such as step-up and step-down configurations, having different aspect ratios and relative heights of the buildings. The results show a clear dependence of the ACH on the latter two parameters and highlight the role played by the turbulence in the exchange of air mass, particularly important for the step-down configurations, when the ventilation associated with the mean flow is generally poor.

scholarly journals Relationship between dynamic knee valgus and lateral trunk lean during single-leg squatting in two-dimensional image

2020 ◽  
Vol 69 (3) ◽  
pp. 261-267
Author(s):  
Satoshi Koto ◽  
Yoshinori Kagaya ◽  
Shohei Sato ◽  
Risa Yamauchi ◽  
Ryosuke Yumigeta ◽  
...  
Keyword(s):  
Knee Valgus ◽  
Two Dimensional ◽  
Dimensional Image ◽  
Two Dimensional Image

scholarly journals Systematic video analysis of ACL injuries in professional male football (soccer): injury mechanisms, situational patterns and biomechanics study on 134 consecutive cases

2020 ◽  
Vol 54 (23) ◽  
pp. 1423-1432 ◽  
Author(s):  
Francesco Della Villa ◽  
Matthew Buckthorpe ◽  
Alberto Grassi ◽  
Alberto Nabiuzzi ◽  
Filippo Tosarelli ◽  
...  
Keyword(s):  
Video Analysis ◽  
Direct Contact ◽  
Acl Injury ◽  
Injury Pattern ◽  
Biomechanical Analysis ◽  
Knee Valgus ◽  
Mechanical Perturbation ◽  
Indirect Contact ◽  
Acl Injuries ◽  
Injury Mechanisms

BackgroundA few small studies have reported on the mechanisms of ACL injury in professional male football.AimTo describe the mechanisms, situational patterns and biomechanics (kinematics) of ACL injuries in professional male football matches.MethodsWe identified 148 consecutive ACL injuries across 10 seasons of professional Italian football. 134 (90%) injury videos were analysed for mechanism and situational pattern, while biomechanical analysis was possible in 107 cases. Three independent reviewers evaluated each video. ACL injury epidemiology (month), timing within the match and pitch location at the time of injury were also reported.Results59 (44%) injuries were non-contact, 59 (44%) were indirect contact and 16 (12%) were direct contact. Players were frequently perturbed immediately prior to injury. We identified four main situational patterns for players who suffered a non-contact or an indirect contact injury: (1) pressing and tackling (n=55); (2) tackled (n=24); (3) regaining balance after kicking (n=19); and (4) landing from a jump (n=8). Knee valgus loading (n=83, 81%) was the dominant injury pattern across all four of these situational patterns (86%, 86%, 67% and 50%, respectively). 62% of the injuries occurred in the first half of the matches (p<0.01). Injuries peaked at the beginning of the season (September–October) and were also higher at the end of the season (March–May).Conclusions88% of ACL injuries occurred without direct knee contact, but indirect contact injuries were as frequent as non-contact injuries, underlying the importance of mechanical perturbation. The most common situational patterns were pressing, being tackled and kicking.

Relationships between Knee Valgus, Hip-Muscle Strength, and Hip-Muscle Recruitment during a Single-Limb Step-Down

2009 ◽  
Vol 18 (1) ◽  
pp. 104-117 ◽  
Author(s):  
John H. Hollman ◽  
Barbara E. Ginos ◽  
Jakub Kozuchowski ◽  
Amanda S. Vaughn ◽  
David A. Krause ◽  
...  
Keyword(s):  
Muscle Strength ◽  
External Rotation ◽  
Frontal Plane ◽  
Gluteus Maximus ◽  
Knee Valgus ◽  
Outcome Measurements ◽  
Hip Muscle ◽  
Hip Abduction ◽  
Step Down ◽  
Rotation Strength

Context:Reduced strength and activation of hip muscles might correlate with increased weight-bearing knee valgus.Objective:To describe relationships among frontal-plane hip and knee angles, hip-muscle strength, and electromyographic (EMG) recruitment in women during a step-down.Design:Exploratory study.Setting:Laboratory.Participants:20 healthy women 20 to 30 years of age.Interventions:Frontal-plane hip and knee angles were measured. Gluteus maximus and medius recruitment were examined with surface EMG. Hip-abduction and -external-rotation strength were quantified with handheld dynamometry.Main Outcome Measurements:The authors analyzed correlation coefficients between knee and hip angles, gluteus maximus and medius EMG, and hip-abduction and -external-rotation strength.Results:Hip-adduction angles (r = .755, P = .001), gluteus maximus EMG (r = −.451, P = .026), and hip-abduction strength (r = .455, P = .022) correlated with frontal-plane projections of knee valgus.Conclusions:Gluteus maximus recruitment might have greater association with reduced knee valgus in women than does external-rotation strength during step-down tasks. Gluteus medius strength might be associated with increased knee valgus.

Two-Dimensional Video Analysis of the Upper Eyelid Motion During Spontaneous Blinking

2014 ◽  
Vol 30 (2) ◽  
pp. 146-151 ◽  
Author(s):  
Sarah P. F. Wambier ◽  
Sara F. Ribeiro ◽  
Denny M. Garcia ◽  
Rodrigo R. Brigato ◽  
Andre Messias ◽  
...  
Keyword(s):  
Video Analysis ◽  
Two Dimensional ◽  
Upper Eyelid

Reliability of 2-Dimensional Video Assessment of Frontal-Plane Dynamic Knee Valgus During Common Athletic Screening Tasks

2012 ◽  
Vol 21 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Allan Munro ◽  
Lee Herrington ◽  
Michael Carolan
Keyword(s):  
Measurement Error ◽  
Video Analysis ◽  
Outcome Measurement ◽  
Cruciate Ligament ◽  
Frontal Plane ◽  
Pain Syndrome ◽  
Individual Performance ◽  
Knee Valgus ◽  
Good Reliability ◽  
Single Leg Squat

Context:Two-dimensional (2D) video analysis of frontal-plane dynamic knee valgus during common athletic screening tasks has been purported to identify individuals who may be at high risk of suffering knee injuries such as anterior cruciate ligament tear or patellofemoral pain syndrome. Although the validity of 2D video analysis has been studied, the associated reliability and measurement error have not.Objective:To assess the reliability and associated measurement error of a 2D video analysis of lower limb dynamic valgus.Design:Reliability study.Participants:20 recreationally active university students (10 women age 21.5 ± 2.3 y, height 170.1 ± 6.1 cm, weight 66.2 ± 10.2 kg, and 10 men age 22.6 ± 3.1 y, height 177.9 ± 6.0 cm, weight 75.8 ± 7.9 kg).Main Outcome Measurement:Within-day and between-days reliability and measurement-error values of 2D frontal-plane projection angle (FPPA) during common screening tasks.Interventions:Participants performed single-leg squat and drop jump and single-leg landings from a standard 28-cm step with standard 2D digital video camera assessment.Results:Women demonstrated significantly higher FPPA in all tests except the left single-leg squat. Within-day ICCs showed good reliability and ranged from .59 to .88, and between-days ICCs were good to excellent, ranging from .72 to .91. Standard error of measurement and smallest detectable difference values ranged from 2.72° to 3.01° and 7.54° to 8.93°, respectively.Conclusions:2D FPPA has previously been shown to be valid and has now also been shown to be a reliable measure of lower extremity dynamic knee valgus. Using the measurement error values presented along with previously published normative data, clinicians can now make informed judgments about individual performance and changes in performance resulting from interventions.

scholarly journals Reliability of two-dimensional measures associated with bilateral drop-landing performance

2020 ◽  
pp. 39-47
Author(s):  
Louis Howe ◽  
Theodoros M. Bampouras ◽  
Jamie S. North ◽  
Mark Waldron
Keyword(s):  
Video Analysis ◽  
Frontal Plane ◽  
Contact Angles ◽  
Initial Contact ◽  
Systematic Bias ◽  
Two Dimensional ◽  
Drop Landing ◽  
Joint Displacement ◽  
Drop Landings ◽  
Absolute Reliability

The aim of this study was to establish the within-session reliability for two-dimensional (2D) video analysis of sagittal- and frontal-plane measures during bilateral drop-landing tasks. Thirty-nine recreational athletes (22 men, 17 women, age = 22 ± 4 years, height = 1.74 ± 0.15 m, body mass 70.2 ± 15.1 kg) performed five bilateral drop-landings from 50, 100 and 150% of maximum countermovement jump height, twice on the same day. Measures of reliability for initial contact angle, peak flexion angle and joint displacement for the hip, knee, and ankle joints, frontal-plane projection angles (FPPA), as well as inter-limb asymmetries in joint displacement were assessed. No systematic bias was present between trials (P>0.05). All kinematic measurements showed relative reliability ranging from large to near perfect (ICC = 0.52–0.96). Absolute reliability ranged between measures, with CV% between 1.0–1.6% for initial contact angles, 1.9–7.9% for peak flexion angles, 5.3–22.4% for joint displacement, and 1.6–2.3% for FPPA. Absolute reliability for inter-limb asymmetries in joint displacement were highly variable, with minimal detectable change values ranging from 6.0–13.2°. Therefore, 2D video analysis is a reliable tool for numerous measures related to the performance of bilateral drop-landings.

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