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.

Influence of External Ankle Support on Lower Extremity Joint Mechanics During Drop Landings

2010 ◽  
Vol 19 (2) ◽  
pp. 136-148 ◽  
Author(s):  
Mitchell L. Cordova ◽  
Yosuke Takahashi ◽  
Gregory M. Kress ◽  
Jody B. Brucker ◽  
Alfred E. Finch
Keyword(s):  
Knee Joint ◽  
Lower Extremity ◽  
Outcome Measures ◽  
Repeated Measures ◽  
Angular Displacement ◽  
Joint Mechanics ◽  
Drop Landing ◽  
Joint Displacement ◽  
Ankle Support ◽  
Drop Landings

Objective:To investigate the effects of external ankle support (EAS) on lower extremity joint mechanics and vertical ground-reaction forces (VGRF) during drop landings.Design:A 1 × 3 repeated-measures, crossover design.Setting:Biomechanics research laboratory.Patients:13 male recreationally active basketball players (age 22.3 ± 2.2 y, height 177.5 ± 7.5 cm, mass 72.2 ± 11.4 kg) free from lower extremity pathology for the 12 mo before the study.Interventions:Subjects performed a 1-legged drop landing from a standardized height under 3 different ankle-support conditions.Main Outcome Measures:Hip, knee, and ankle angular displacement along with specific temporal (TGRFz1, TGRFz2; s) and spatial (GRFz1, GRFz2; body-weight units [BW]) characteristics of the VGRF vector were measured during a drop landing.Results:The tape condition (1.08 ± 0.09 BW) demonstrated less GRFz1 than the control (1.28 ± 0.16 BW) and semirigid conditions (1.28 ± 0.21 BW; P < .0001), and GRFz2 was unaffected. For TGRFz1, no-support displayed slower time (0.017 ± 0.004 s) than the semirigid (0.014 ± 0.001 s) and tape conditions (0.014 ± 0.002 s; P < .05). For TGRFz2, no-support displayed slower time (0.054 ±.006 s) than the semirigid (0.050 ± 0.006 s) and tape conditions (0.045 ± 0.004 s; P < .05). Semirigid bracing was slower than the tape condition, as well (P < .05). Ankle-joint displacement was less in the tape (34.6° ± 7.7°) and semirigid (36.8° ± 9.3°) conditions than in no-support (45.7° ± 7.3°; P < .05). Knee-joint displacement was larger in the no-support (45.1° ± 9.0°) than in the semirigid (42.6° ± 6.8°; P < .05) condition. Tape support (43.8° ± 8.7°) did not differ from the semirigid condition (P > .05). Hip angular displacement was not affected by EAS (F2,24 = 1.47, P = .25).Conclusions:EAS reduces ankle- and knee-joint displacement, which appear to influence the spatial and temporal characteristics of GRFz1 during drop landings.

Segment Kinematics Differ Between Jump and Drop Landings Regardless of Practice

2015 ◽  
Vol 31 (5) ◽  
pp. 357-362 ◽  
Author(s):  
Loren Z.F. Chiu ◽  
Amy N. Moolyk
Keyword(s):  
Lower Extremity ◽  
Control Strategies ◽  
Plantar Flexion ◽  
Initial Contact ◽  
Jump Landing ◽  
Drop Landing ◽  
Landing Mechanics ◽  
Peak Knee ◽  
Drop Landings ◽  
Specific Control

Joint kinematics differ between jump and drop landings and there is evidence that segment kinematics may also be different. The purpose of this research was to compare lower extremity segment kinematics for jump and drop landings, and to examine if multiple days of practice would influence these kinematics. Men (n = 9) and women (n = 15) performed 4 sessions of jump and drop landings (40 cm and 60 cm) in a motion-capture laboratory. Segment kinematics at initial contact, foot flat, and peak knee flexion were compared between landing types and across visits. At initial contact, foot plantar flexion was greater in jump versus drop landings (P < .05). At initial contact and foot flat, forward leg inclination and pelvis flexion were greater in jump landing (P < .05), while thigh flexion was greater in drop landings (P > .05). The differences in leg and thigh angles at initial contact and foot flat altered lower extremity posture. These results are in contrast to a previous study; this suggests that drop landing can be modified to have the same mechanics as jump landing. As practice did not influence drop landing mechanics (P > .05), specific control strategies and instructions need to be identified.

Ankle Dorsiflexion Displacement During Landing is Associated With Initial Contact Kinematics but not Joint Displacement

2015 ◽  
Vol 31 (4) ◽  
pp. 205-210 ◽  
Author(s):  
Rebecca L. Begalle ◽  
Meghan C. Walsh ◽  
Melanie L. McGrath ◽  
Michelle C. Boling ◽  
J. Troy Blackburn ◽  
...  
Keyword(s):  
Injury Risk ◽  
Sagittal Plane ◽  
Plantar Flexion ◽  
Three Dimensional ◽  
Contact Angles ◽  
Ankle Dorsiflexion ◽  
Lower Extremity Injury ◽  
Initial Contact ◽  
Joint Displacement ◽  
Jump Landings

The ankle, knee, and hip joints work together in the sagittal plane to absorb landing forces. Reduced sagittal plane motion at the ankle may alter landing strategies at the knee and hip, potentially increasing injury risk; however, no studies have examined the kinematic relationships between the joints during jump landings. Healthy adults (N = 30; 15 male, 15 female) performed jump landings onto a force plate while three-dimensional kinematic data were collected. Joint displacement values were calculated during the loading phase as the difference between peak and initial contact angles. No relationship existed between ankle dorsiflexion displacement during landing and three-dimensional knee and hip displacements. However, less ankle dorsiflexion displacement was associated with landing at initial ground contact with larger hip flexion, hip internal rotation, knee flexion, knee varus, and smaller plantar flexion angles. Findings of the current study suggest that restrictions in ankle motion during landing may contribute to contacting the ground in a more flexed position but continuing through little additional motion to absorb the landing. Transverse plane hip and frontal plane knee positioning may also occur, which are known to increase the risk of lower extremity injury.

scholarly journals Reliability of Two-Dimensional Video-Based Analysis in Adolescent Runners

2021 ◽  
Vol 9 (7_suppl3) ◽  
pp. 2325967121S0007
Author(s):  
Yukiko Matsuzaki ◽  
Madison R. Heath ◽  
Julianne M. Khan ◽  
Elad Spitzer ◽  
Peter D. Fabricant
Keyword(s):  
Video Analysis ◽  
Physical Therapist ◽  
Intraclass Correlation ◽  
Frontal Plane ◽  
Two Dimensional ◽  
Step Width ◽  
High Definition ◽  
Perfect Agreement ◽  
Rater Reliability ◽  
Adolescent Population

Background: Running analysis is an essential component of evaluation of both injured runners and uninjured runners seeking advice on injury prevention. Reliability of two-dimensional (2D) video analysis has been reported in the adult running population. However, these findings may not apply to youth runners given their unique state during growth and development. The reliability of quantitative and qualitative video-based running gait analysis in the adolescent population is unknown. Purpose: The purpose of this study was to determine the intra-rater and inter-rater reliability of sagittal and frontal plane kinematics using 2D video analysis in healthy adolescent runners. Methods: High-definition videos were recorded of 10 healthy runners between 14-18 years old running on a treadmill at self-selected speed with markers attached to the thoracic spine, pelvis, and lower extremities. Kinematic variables in the sagittal and frontal planes were measured using Dartfish Motion Analysis Software™ (Fribourg, Switzerland) by three raters. Intra- and inter-rater reliability were calculated using Intraclass Correlation Coefficients (ICCs). Results: Of the 10 runners, 4 (40%) were male and the mean age was 16 ± 1.5 years. The intra-rater ICC for all kinematic variables ranged from 0.574 to 0.999 for the primary sports physical therapist, and 0.367 to 0.973 for the inexperienced research assistant. The inter-rater ICC for all raters ranged from -0.01 to 0.941. Eleven kinematic variables showed substantial agreement and 4 showed almost perfect agreement. Step width and foot progression showed fair and poor agreement, respectively. Conclusion: The results of this study demonstrate that a 2D video-based running analysis can be reliably performed in an adolescent population on all kinematic variables except for step width and foot progression. Inexperienced raters can be properly trained in the video analysis of running kinematics using Dartfish Software in order to consistently assess the same runner. [Table: see text][Table: see text]

Two- and Three-Dimensional Relationships Between Knee and Hip Kinematic Motion Analysis: Single-Leg Drop-Jump Landings

2015 ◽  
Vol 24 (4) ◽  
pp. 363-372 ◽  
Author(s):  
Bryan Sorenson ◽  
Thomas W. Kernozek ◽  
John David Willson ◽  
Robert Ragan ◽  
Jordan Hove
Keyword(s):  
Motion Analysis ◽  
Sagittal Plane ◽  
Strong Association ◽  
Knee Kinematics ◽  
Frontal Plane ◽  
Strong Relationship ◽  
Transverse Plane ◽  
Lower Extremity Injury ◽  
Initial Contact ◽  
Drop Landings

Context:Hip- and knee-joint kinematics during drop landings are relevant to lower-extremity injury mechanisms. In clinical research the “gold standard” for joint kinematic assessment is 3-dimensional (3D) motion analysis. However, 2-dimensional (2D) kinematic analysis is an objective and feasible alternative.Objective:To quantify the relationship between 2D and 3D hip and knee kinematics in single-leg drop landings and test for a set of 3D hip and knee kinematics that best predicts 2D kinematic measures during single-leg drop landings Design: Descriptive, comparative laboratory study.Participants:31 healthy college-age women (65.5 kg [SD 12.3], 168.1 cm [SD 6.7]).Methods:Participants performed five 40-cm single-leg landings during motion capture at 240 Hz. Multiple regressions were used to predict relationships for knee and hip between 2D frontal-plane projection angles (FPPA) and 3D measurements.Results:2D knee FPPA had a strong relationship with 3D frontal-plane knee kinematics at initial contact (IC) (r2 = .72), which was only minimally improved with the addition of knee sagittal-plane and hip transverse-plane positions at IC (r2 = .77). In contrast, 2D knee FPPA had a low relationship with 3D knee-abduction excursion (r2 = .06). The addition of knee sagittal-plane and hip transverse-plane motions did not improve this relationship (r2 = .14). 2D hip FPPA had a moderate relationship with 3D frontal-plane hip position at IC (r2 = .52), which was strengthened with the addition of hip sagittal-plane position (r2 = .60). In addition, hip 2D FPPA into adduction excursion had a strong association with 3D hip-adduction excursion (r2 = .70).Conclusion:2D kinematics can predict 3D frontal-plane hip and knee position at IC during a single-leg landing but predict 3D frontal-plane knee excursion with far less accuracy.

scholarly journals Is contact angle a cause or an effect? – A cautionary tale

2020 ◽  
Vol 146 ◽  
pp. 03004
Author(s):  
Douglas Ruth
Keyword(s):  
Contact Angle ◽  
Solid Surface ◽  
Contact Angles ◽  
Two Dimensions ◽  
Experimental Results ◽  
Flow In Porous Media ◽  
Two Dimensional ◽  
Wide Range ◽  
Fluid Drop ◽  
Surrounding Fluid

The most influential parameter on the behavior of two-component flow in porous media is “wettability”. When wettability is being characterized, the most frequently used parameter is the “contact angle”. When a fluid-drop is placed on a solid surface, in the presence of a second, surrounding fluid, the fluid-fluid surface contacts the solid-surface at an angle that is typically measured through the fluid-drop. If this angle is less than 90°, the fluid in the drop is said to “wet” the surface. If this angle is greater than 90°, the surrounding fluid is said to “wet” the surface. This definition is universally accepted and appears to be scientifically justifiable, at least for a static situation where the solid surface is horizontal. Recently, this concept has been extended to characterize wettability in non-static situations using high-resolution, two-dimensional digital images of multi-component systems. Using simple thought experiments and published experimental results, many of them decades old, it will be demonstrated that contact angles are not primary parameters – their values depend on many other parameters. Using these arguments, it will be demonstrated that contact angles are not the cause of wettability behavior but the effect of wettability behavior and other parameters. The result of this is that the contact angle cannot be used as a primary indicator of wettability except in very restricted situations. Furthermore, it will be demonstrated that even for the simple case of a capillary interface in a vertical tube, attempting to use simply a two-dimensional image to determine the contact angle can result in a wide range of measured values. This observation is consistent with some published experimental results. It follows that contact angles measured in two-dimensions cannot be trusted to provide accurate values and these values should not be used to characterize the wettability of the system.

scholarly journals Relationship Between 2-Dimensional Frontal Plane Measures and the Knee Abduction Angle During the Drop Vertical Jump

2019 ◽  
Vol 28 (4) ◽  
Author(s):  
Brad W. Willis ◽  
Katie Hocker ◽  
Swithin Razu ◽  
Aaron D. Gray ◽  
Marjorie Skubic ◽  
...  
Keyword(s):  
Motion Capture ◽  
Vertical Jump ◽  
Frontal Plane ◽  
Ligament Injury ◽  
Coefficient Of Determination ◽  
Abduction Angle ◽  
Initial Contact ◽  
Knee Abduction ◽  
The Relationship ◽  
Drop Vertical Jump

Context: Knee abduction angle (KAA), as measured by 3-dimensional marker-based motion capture systems during jump-landing tasks, has been correlated with an elevated risk of anterior cruciate ligament injury in females. Due to the high cost and inefficiency of KAA measurement with marker-based motion capture, surrogate 2-dimensional frontal plane measures have gained attention for injury risk screening. The knee-to-ankle separation ratio (KASR) and medial knee position (MKP) have been suggested as potential frontal plane surrogate measures to the KAA, but investigations into their relationship to the KAA during a bilateral drop vertical jump task are limited. Objective: To investigate the relationship between KASR and MKP to the KAA during initial contact of the bilateral drop vertical jump. Design: Descriptive. Setting: Biomechanics laboratory. Participants: A total of 18 healthy female participants (mean age: 24.1 [3.88] y, mass: 65.18 [10.34] kg, and height: 1.63 [0.06] m). Intervention: Participants completed 5 successful drop vertical jump trials measured by a Vicon marker-based motion capture system and 2 AMTI force plates. Main Outcome Measure: For each jump, KAA of the tibia relative to the femur was measured at initial contact along with the KASR and MKP calculated from planar joint center data. The coefficient of determination (r2) was used to examine the relationship between the KASR and MKP to KAA. Results: A strong linear relationship was observed between MKP and KAA (r2 = .71), as well as between KASR and KAA (r2 = .72). Conclusions: Two-dimensional frontal plane measures show strong relationships to the KAA during the bilateral drop vertical jump.

Static postural differences between male and female equestrian riders on a riding simulator

2021 ◽  
pp. 1-8
Author(s):  
T.L. Bye ◽  
R. Martin
Keyword(s):  
Kinematic Analysis ◽  
Pelvic Tilt ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Exercise Programme ◽  
Pelvic Obliquity ◽  
Force Distribution ◽  
Two Dimensional ◽  
Postural Asymmetry ◽  
Male And Female

This study aimed to compare static posture of male and female riders on a riding simulator. Ten female and five male riders underwent a 5 min standardised exercise programme on the simulator, they were then videoed for 10 s from each the left, right, and rear views whilst stationary on the simulator. Two-dimensional kinematic analysis of the videos showed that male riders had a more neutrally positioned pelvis in the sagittal plane (median left: 6.47°, right: 5.24°) with females demonstrating a posterior pelvic tilt (L: 14.04°, R: 13.55°). Females showed significantly greater pelvic obliquity (median female: 1.99°, male: 0.73°), trunk lean (F: 1.60°, M: 0.43°), and shoulder tilt (F: 1.79°, M: 0.57°) in the frontal plane, demonstrating an overall greater postural asymmetry. Previous studies of elite riders have shown a more anteriorly rotated pelvis to be more desirable. Symmetry of riding position is favourable as it allows movements to be performed with ease and ensures even force distribution through the saddle to the horse. Male riders may therefore have a biomechanical advantage over females when it comes to maintaining a desirable riding position. This research should now be extended to study riders on the horse in motion.

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