Two-dimensional Video Analysis Research Articles

Unsupervised machine learning for clustering forward head posture, protraction and retraction movement patterns based on craniocervical angle data in individuals with nonspecific neck pain

ObjectivesThe traditional understanding of craniocervical alignment emphasizes specific anatomical landmarks. However, recent research has challenged the reliance on forward head posture as the primary diagnostic criterion for neck pain. An advanced relationship exists between neck pain and craniocervical alignment, which requires a deeper exploration of diverse postures and movement patterns using advanced techniques, such as clustering analysis. We aimed to explore the complex relationship between craniocervical alignment, and neck pain and to categorize alignment patterns in individuals with nonspecific neck pain using the K-means algorithm.MethodsThis study included 229 office workers with nonspecific neck pain who applied unsupervised machine learning techniques. The craniocervical angles (CCA) during rest, protraction, and retraction were measured using two-dimensional video analysis, and neck pain severity was assessed using the Northwick Park Neck Pain Questionnaire (NPQ). CCA during sitting upright in a comfortable position was assessed to evaluate the resting CCA. The average of midpoints between repeated protraction and retraction measures was considered as the midpoint CCA. The K-means algorithm helped categorize participants into alignment clusters based on age, sex and CCA data.ResultsWe found no significant correlation between NPQ scores and CCA data, challenging the traditional understanding of neck pain and alignment. We observed a significant difference in age (F = 140.14, p < 0.001), NPQ total score (F = 115.83, p < 0.001), resting CCA (F = 79.22, p < 0.001), CCA during protraction (F = 33.98, p < 0.001), CCA during retraction (F = 40.40, p < 0.001), and midpoint CCA (F = 66.92, p < 0.001) among the three clusters and healthy controls. Cluster 1 was characterized by the lowest resting and midpoint CCA, and CCA during pro- and -retraction, indicating a significant forward head posture and a pattern of retraction restriction. Cluster 2, the oldest group, showed CCA measurements similar to healthy controls, yet reported the highest NPQ scores. Cluster 3 exhibited the highest CCA during protraction and retraction, suggesting a limitation in protraction movement.DiscussionAnalyzing 229 office workers, three distinct alignment patterns were identified, each with unique postural characteristics; therefore, treatments addressing posture should be individualized and not generalized across the population.

Kinematics of 90° change of direction in young football players: Insights for ACL injury prevention from the CUTtheACLstudy on 6008 trials.

To investigate the 90° change of direction (COD) task in an extensive cohort of competitive healthy football players within the CUTtheACLstudy and to provide normative values and differences between males and females for full-body kinematics based on two-dimensional (2D) video analysis and scoring system. One-thousand-and-two competitive football (soccer) players (age 16.3 ± 2.8 years, 264 females) were prospectively enroled. Each player performed three preplanned 90° COD tasks per limb. The 2D evaluation was performed through objective measures (collected through three high-speed cameras) of frontal and sagittal plane joint kinematics at the cut initial foot contact (IC) and maximum knee flexion angle. A previously published scoring system was adopted to measure the movement quality of the COD task. The scoring system included five criteria (limb stability [LS], pelvis stability [PS], trunk stability [TS], shock absorption [SA], movement strategy [MS]) ranked from 0/2 (nonadequate) to 2/2 (adequate) with a maximum score of 10/10. Normative data were provided for all the variables; statistical differences between male and female players were investigated (p < 0.05). A total of 6008 valid attempts were included. Frontal plane knee projection angle (FPKPA) at initial contact was 24.4 ± 9.8° (95thpercentile: FPKPA > 40°). The total score was ≤4/10 in 71.2% of the trials, the lowest subscores were LS and PS. Female players showed different movement patterns with lower hip and trunk flexion both at IC and maximum knee flexion angle (p < 0.01, ES = 0.41-0.64). Female players also showed worse scores than males in SA, MSand total score (p < 0.01). Female players seem more prone to stiffer lower limb strategy and greater pelvis-trunk frontal plane instability than males. Clinicians could adopt normative data and sex-specific differences in players' movement techniques to improve ACL injury risk mitigation protocols. Level IV.

A comprehensive two-dimensional scoring system to assess the single-leg squat task in football players

BackgroundThe single-leg squat (SLS) is a safe and widespread functional test commonly performed in the mid-stages of rehabilitation after severe knee injuries. The use of reliable objective measures has been advocated to improve the quality of SLS assessment. The aim of this study was to describe a qualitative whole-body scoring system based on two-dimensional (2D) video analysis during SLS test and validate it against three-dimensional (3D) kinetics and kinematics. MethodsThirty-four competitive football (soccer) players performed a series of SLS tasks. 3D kinematics and kinetics were collected through infrared cameras, and 2D video analysis was performed through a scoring system with sub-scores ranging from 0/2 (non-adequate movement) to 2/2 (adequate movement) based on frontal and lateral planes objective measurements. 3D kinematics and kinetics were grouped according to the results of the 2D evaluation and compared through the analysis of variance (P < 0.05). ResultsHigher hip adduction, hip internalrotation, and knee valgus collapse were found in trials rated 0/2 or 1/2 compared with theone rated 2/2 in the limb stability score. Hip flexion and hip/knee moment ratio were lower in those scoring 0/2 comparedwith those scoring 2/2 in the movement strategy criterion. A low total score was associated with higherknee valgus collapse and lower hip/knee extensor moment ratio. Compensatory strategieswere found in frontal plane scores. ConclusionsThe 2D scoring system described was strongly associated with kinematics and kinetics from gold-standard 3D motion capture and might represent a valid tool to describe the movement quality of an SLS task.

Assessing the validity of two-dimensional video analysis for measuring lower limb joint angles during fencing lunge.

The fencing lunge (lunge), characterized by minimal body rotation, offers a movement well-suited for 2D video analysis. However, to the best of our knowledge, the validity of 2D video analysis for fencing has not been verified. This study aimed to validate 2D video analysis by comparing lower limb joints (hip, knee, and ankle joints) angles during lunge using both 2D video analysis and 3D motion analysis methods. Twenty-two male fencers performed lunge trials that were simultaneously recorded using eight motion capture cameras (Qualisys Miqus M1) and two digital video cameras (Sony AX-450 and AX450a). The 2D video analysis results exhibited an extremely large correlation in knee joint angles of the front and rear legs in the sagittal with those from 3D motion analysis (r = 0.93-0.99). However, while a robust correlation was found between the ankle joint angles of the front and rear legs (r = 0.82-0.84), a large bias was also observed (-5.23° to -21.31°). Conversely, for the hip joints of the rear leg, a moderate correlation (r = 0.31) and a large bias (-10.89°) were identified. The results of this study will contribute to the development of coaching using 2D video analysis in competition settings because such analysis can be a useful alternative to 3D motion analysis when measuring the knee joint angle of the front leg and rear leg in the sagittal plane. However, for the ankle joint angle, further research on the optimal shooting position and height of the digital video camera is needed, whereas for the hip joint angle, 3D motion analysis is recommended at this time.

Two-dimensional video analysis of the overhead squat: a preliminary study

The aim of this study was to identify changes in the pattern of movement during performance of the overhead squat, as well as possible differences between the sexes, during a protocol of an extreme conditioning program. The subjects were eleven men (28.6 ± 4.5 years, 85.1 ± 8.4 kg, 1.80 ± 0.07 m, and 13.8 ± 7.7 months of practice) and eleven women (30.5 ± 4.8 years, 68.2 ± 10.36 kg, 1.70 ± 0.05 m, and 20.3 ± 17.01 months of practice), all of whom were extreme conditioning program practitioners. The protocol chosen for the training was the “Nautical Nancy”, which consisted of 5 rounds of 15 overhead squats and 400 meters of rowing. During the exercise, an analysis was performed in which the shoulder, knee, and hip flexion angles were analyzed in the first and last rounds. For men, there were increases of the shoulder and hip flexion angles, while the women showed increase of the shoulder flexion angle and decrease of the knee flexion angle. Changes in technique occurred due to the attempt at self-preservation on the part of the practitioners, when exposed to the protocol, which could lead to increased risk of injury. Key words: CrossFit; High Intensity Functional Training; Resistance Training; Biomechanics; Exercise Technique.

Saddle Thigh Block Design Can Influence Rider and Horse Biomechanics.

The association between rider-saddle interaction and horse kinematics has been little studied. It was hypothesized that differences in a thigh block design would influence (a) rider-saddle interface pressures, (b) rider kinematics, and (c) equine limb/spinal kinematics. Eighteen elite sport horses/riders were trotted using correctly fitted dressage saddles with thigh blocks S (vertical face) and F (deformable face). Contact area, mean, and peak pressure between rider and saddle were determined using an on-saddle pressure mat. Spherical markers allowed for the measurement of horse/rider kinematics using two-dimensional video analysis. The kinematics of the equine thoracolumbosacral spine were obtained using skin-mounted inertial measuring units. Results were compared between thigh blocks (paired t-test p ≤ 0.05). With F, the contact area, mean, and peak pressure between rider and saddle were significantly higher (p = 0.0001), and the rider trunk anterior tilt was reduced, indicating altered rider-saddle interaction. The horse thoracic axial rotation and flexion/extension were reduced (p = 0.01-0.03), caudal thoracic and lumbar lateral bend was increased (p = 0.02-0.04), and carpal flexion increased (p = 0.01-0.05) with F compared to S. During straight-line locomotion when in sitting trot, thigh block F was associated with altered rider-saddle interaction and rider and equine kinematics, leading to a more consistent rider-saddle interface, a more upright rider trunk during stance, an increased horse thoracic stability and lumbar lateral bend, and forelimb flexion, supporting the importance of optimising rider-saddle-horse interaction.

Reliability and validity of 2D-video analysis to objectively assess hamstring performance during the H-test

ABSTRACT The H-test is commonly used during return-to-sport decisions after hamstring muscle injury. The primary aim was to evaluate the reliability of two-dimensional (2D) video analysis for the H-Test. The second aim was to assess its validity compared to an electronic gyroscope (gold standard), and the third aim was to establish normative values. We conducted a cross-sectional study including 30 healthy individuals. Mean, maximal velocities (VMean and Vmax) and range of motion (ROM) of hip flexion were captured during the H-test to evaluate inter-rater and test-retest reliability using intraclass correlation coefficient (ICC2,1) and standard error of measurement (SEM). Correlation analysis (r) and as typical error of estimate (TEE) were used to assess the validity between the video and the gyroscope. Reliability was excellent for ROM (ICC:0.91, [95% CI:0.83–0.95]), moderate for VMean (ICC:0.57; [95% CI:0.32–0.74]) and VMax (ICC:0.64, [95% CI:0.43–0.79]). Strong positive correlations were found between video and gyroscope for VMean (r = 0.79, [95% CI:0.71–0.86]) and VMax (r = 0.84, [95% CI:0.77–0.89]) and very strong for ROM (r = 0.89, [95% CI:0.85–0.93]). Males exhibited a higher VMax (p < 0.001) than females, while females had a higher ROM (p < 0.001). 2D-video analysis is a valid and reliable method to assess ROM during the H-Test and could easily be implemented in clinical practice.

Comparison of the "Tall and Fall" Versus "Drop and Drive" Pitching Styles: Analysis of Major League Baseball Pitchers During a Single Season.

Previous research has documented the proportion of "tall and fall" (TF) and "drop and drive" (DD) pitching styles among Major League Baseball (MLB) pitchers who underwent ulnar collateral ligament reconstruction (UCLR). The proportion of these 2 styles among all MLB pitchers remains unknown. To determine the proportion of the TF and DD pitching styles in all rostered MLB pitchers during a single season as well as the proportion of TF and DD pitchers who sustained an upper extremity (UE) injury and those who underwent UCLR. Cross-sectional study; Level of evidence, 3. Pitcher demographic characteristics from the 2019 MLB season and pitching information were obtained via open-access sources. Two-dimensional video analysis was used to categorize the included pitchers into TF and DD groups. Statistical comparisons and contrasts were made using 2-tailed t tests, chi-square tests, and Pearson correlation analyses as appropriate. Of the 660 MLB rostered pitchers in 2019 (age, 27.39 ± 3.51 years; body mass index, 26.34 ± 2.47 kg/m2; fastball velocity, 150.49 ± 3.99 kph [93.51 ± 2.48 mph]), 412 (62.4%) pitchers used the TF style and 248 (37.6%) pitchers used the DD style. Significantly more UE injuries were seen in the TF group compared with the DD group (112 vs 38 injuries, respectively; P < .001). Twelve pitchers underwent UCLR (TF, 10; DD, 2), representing a 1.8% UCLR rate among all pitchers. This was a second surgery for 2 pitchers, both of whom used the TF pitching style. Significantly more pitchers in the TF group than the DD group had undergone UCLR before 2019 (135 vs 56 pitchers, respectively; P = .005). The results of the present study demonstrated a higher prevalence of both UE injury and prior UCLR in TF pitchers. Further research is needed to explore the potential association between pitching style and UE injury.

Assessment of Dynamic Knee Valgus between Lateral Step-Down Test and Running in Female Runners with and without Patellofemoral Pain Using Two-Dimensional Video Analysis.

Dynamic knee valgus (DKV) is a frontal plane knee kinematic alteration that has been associated with patellofemoral pain (PFP) in female runners. DKV is commonly assessed in clinical practice by measuring frontal plane knee projection angle (FPPA) during squat tests. However, it remains unclear whether the DKV observed in these tests is similar to or correlates with that observed during running in female runners. The aims of this cross-sectional study were to correlate and compare DKV, by measuring FPPA values, in a lateral step-down (LSD) squat test and running in female runners with and without PFP. A two-dimensional (2D) video analysis of the LSD test and running was carried out for 21 asymptomatic female runners and 17 PFP female runners in order to determine FPPA values. A Pearson correlation test and a factorial ANOVA with Bonferroni post hoc correction were used for statistical analysis. The FPPAs recorded in the LSD test were significantly higher than those recorded during running in the asymptomatic (16.32° ± 5.38 vs. 4.02° ± 3.26, p < 0.01) and PFP groups (17.54° ± 7.25 vs. 4.64° ± 3.62, p < 0.01). No significant differences were found in FPPA values between asymptomatic and PFP runners during the LSD test (16.32° ± 5.38 vs. 17.54° ± 7.25, p = 0.55) and running (4.02° ± 3.26 vs. 4.64° ± 3.62, p = 0.58). There was a small (r < 0.3) and non-significant (p > 0.05) correlation in FPPAs between the LSD test and running in both groups. According to our results, DKV was not similar during the LSD test and running, and there was no significant correlation in FPPA values between the LSD test and running in both groups. Therefore, clinicians and therapists should be aware of these findings when using the LSD test in clinical practice to evaluate DKV in female runners with or without PFP.

The Concurrent Validity and Reliability of Single Leg Squat Among Physically Active Females with and without Dynamic Knee Valgus.

BackgroundThe single leg squat (SLS) motion imitates various maneuvers in sports. It is commonly used as a functional test for the lower limb. SLS with two-dimensional (2-D) video analysis is regularly performed in the clinical setting to assess dynamic knee valgus (DKV). However, 2-D video analysis may not be able to demonstrate the same level of accuracy as three-dimensional (3-D) motion analysis.PurposeThis study aimed to determine the within- and between-day reliability as well as the concurrent validity of 2-D and 3-D motion analysis of lower limb kinematics during 45° and 60° SLS among physically active females with and without DKV.Study DesignCross-sectional studyMethodsA total of 34 physically active females (17 individuals with excessive DKV and 17 without DKV) participated in the study. Their DKV was determined based on the cut-off values of knee frontal plane projection angle during drop landing. Their lower limb kinematics during SLS at 45° and 60° knee flexion were captured simultaneously by digital cameras (2-D motion capture) and infrared cameras (3-D motion capture). Intraclass Correlation Coefficient (ICC) was used as an indicator for within- and between-day reliability tests of both groups. Bland-Altman Plot and Pearson correlation were used to examine the validity of 2-D and 3-D motion capture methods in evaluating knee valgus angle.ResultsTwo-dimensional knee FPPA and 3-D knee angle measured during 45° and 60° SLS in normal and excessive DKV groups showed moderate to excellent within-day and between-day reliability (ICC≥ 0.50). The current study showed that the 2-D knee frontal plane projection angle (FPPA) during 45° SLS were valid for the non-dominant leg in both groups. Additionally, the 2-D knee FPPA during 60° SLS were valid for non-dominant leg in excessive DKV group and dominant leg in normal group.ConclusionTwo-dimensional knee FPPA during 45° and 60° SLS also showed high within-and between-day reliability for both groups. The validity of 2-D knee FPPA during SLS depends on the squat depth, stance leg, and presence of DKV.Level of Evidence2B

Video Biomechanical Analysis of Shoulder Impact Kinematics in Tai-Otoshi and Morote-Seoi-Nage Judo Throws: A Cross-Sectional Study

Background: Shoulder injuries in judo are common as the falling player (uke) lands. Two throws implicated in shoulder injury are tai-otoshi and morote-seoi-nage. Kinematic investigation can provide insight into possible shoulder injury mechanisms and allow for appropriate preventative measures to be suggested. We used two-dimensional (2D) video analysis to measure and compare: (a) the peak acceleration and (b) the peak velocity of uke’s shoulder when tai-otoshi and morote-seoi-nage were performed by elite adult judoka. Methods: Eight male participants were recruited from the Budokwai Judo Club in London, UK. The mean age, height, and weight of participants were 25.4 ± 5.2 years (18–34), 1.7 ± 0.0 m (1.7–1.8), and 75.0 ± 5.2 kg (66–80), respectively. Throws were recorded using an iPhone 6S camera and uploaded onto Kinovea for subsequent processing. Results: The peak acceleration (m/s2) was greater in tai-otoshi (71.6 ± 12.4) compared to morote-seoi-nage (67.9 ± 9.9), although this was statistically insignificant. The peak velocity (m/s) was significantly greater (p = 0.030) in tai-otoshi (5.1 ± 0.8) than in morote-seoi-nage (4.5 ± 0.6). Conclusions: A greater peak velocity in tai-otoshi suggests that the shoulder is subjected to increased loads upon impact. This may indicate that tai-otoshi carries a greater risk of shoulder injury. Nage-komi (repetitive throwing) practices in training should follow gradual loading principles—beginning with morote-seoi-nage, before moving to tai-otoshi, for example. We must be aware of any assumptions made in estimations of impact force, and future in vivo research is required to provide more definitive values. Meanwhile, coaches must continue to ensure that correct ukemi (breakfall) technique is displayed by athletes before performing throws.

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

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

Validity and reliability of video analysis to evaluate ankle proprioceptive reintegration during postural control

BackgroundThe ability to dynamically reintegrate proprioceptive signals after they have been perturbated is impaired in certain pathologies. Evaluation of proprioceptive reintegration is useful for clinical practice but currently requires expensive laboratory tools. We developed a simple method, accessible to clinicians.Research question: Is two-dimensional (2D) video analysis of earlobe displacement a valid and reliable tool for the evaluation of ankle proprioceptive reintegration following muscle vibration? MethodsThirty-eight healthy individuals underwent vibration of the triceps surae while standing on a force plate (FP). Anterior (sagittal plane) earlobe displacement (‘overshoot’) was recorded at vibration cessation using 2D video analysis and rated by 3 blind examiners. Correlation analysis was performed between earlobe and center of pressure displacement (dCoP, recorded with the FP) to determine validity. Intra and interrater reliability were determined by calculation of the intraclass correlation coefficient (ICC), change in the mean (CiM), standard error of measurement (SEM) and the minimal detectable change (MDC). Results and significanceStrong positive correlations (r = 0.82–0.94, p < .001) were found between video and FP data. Intra- and interrater reliability were excellent (ICC from 0.99 to 1.00 and from 0.90 to 0.97 respectively). For intrarater analysis, the CiM was 0.01 cm, SEM were 0.27 cm (95% CI: 0.23–0.33) and 3.43% (95% CI: 2.92–4.20) and the MDC was 0.74 cm. For interrater reliability, the CiM ranged from − 0.81–0.55 cm, the SEM from 0.61 to 1.12 cm and the MDC from 1.69 to 3.10 cm. 2D video analysis of anterior (sagittal) earlobe displacement is therefore a valid and reliable method to assess postural recovery following muscle vibration. This simple method could be used by clinicians to evaluate the ability of the central nervous system to reintegrate proprioceptive signals from the ankle. Further studies are needed to assess its validity in individuals with proprioceptive impairment.

Novel biomechanical injury risk score demonstrates correlation with lower limb posterior chain injury in 50 elite-level rugby union athletes

ObjectivesLower limb posterior chain injury (PCI) is common among athletic populations, with multifactorial risk factors including age, previous injury, strength measurements, range of motion and training load. Biomechanics are commonly...

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

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.

THE INVESTIGATION OF APPROACH RUN IN TERMS OF AGE, GENDER, BIO-MOTOR AND TECHNICAL COMPONENTS ON VAULTING TABLE

Vault is one of the main apparatuses for both female and male gymnasts in artistic gymnastics (AG). The optimal vaulting technique depends on many variables, such as the approaching run. Gymnastics is one of the early specialization sports as it is necessary to start training at an early age. For this reason, the aim of the current study was to investigate the relationship among age, biomotor and technical components in relation to the approach run velocity and other variables in AG. Furthermore, similarities and differences between genders were researched. Twenty female and twelve male gymnasts took part in the study. Speed, agility, explosive power, run-up velocity were measured. Additionally, Reactive Strength Index (RSI) and Peak High Velocity distances (PHV_Distance) were calculated. Kinematic parameters during the handspring vault were calculated by a two-dimensional video analysis. A statistical comparison between genders was performed by the Mann Whitney U test. The relationships between parameters were given by Spearman correlation coefficients (r). Anaerobic power, 0-20 m speed, 20 m speed velocity, and the hand contact time were significantly different between genders (p&lt;0.05). The approach run significantly correlated with the chronological age (r=0.66; p=0.002 for female and r=0.96; p&lt;0.001 for male gymnasts), PHV_Distance (r=0.69; p=0.001 for female and r=0.97; p&lt;0.001 for male gymnasts) and the biological age (r=0.69; p=0.001 for female and r=0.97; p&lt;0.001 for male gymnasts). As the approach run velocity increases, vaulting performance is affected positively. While speed tests significantly correlated with the approach run in male gymnasts, there was no correleation for females. In addition, trainers should keep in mind that the relationship between bio-motor development and biological age of gymnasts is important in training programs.

VALIDITY AND RELIABILITY OF VIDEO-BASED ANALYSIS OF UPPER TRUNK ROTATION DURING RUNNING.

Two-dimensional (2D) video analysis is a practical tool for assessing biomechanical factors that may contribute to running-related injury. Asymmetrical or altered coordination of transverse plane trunk movement has been associated with low back pain, increased vertical and horizontal ground reaction forces, and altered hip abduction torque and strength. However, the reliability and validity of 2D transverse plane upper trunk rotation (UTR) has not been assessed. Validity and reliability study. To determine the validity and reliability of 2D video-based, transverse plane UTR measurement during running. Sixteen runners ran at self-selected speed on a treadmill while three-dimensional (3D) and 2D motion capture occurred synchronously. Two raters measured peak UTR for five consecutive strides on two occasions. Interrater and intrarater reliability and the minimum detectable change was calculated for right and left peak 2D UTR measurement. Concurrent validity and agreement between 2D and 3D measures were determined by calculating Pearson Product Correlation Coefficients (r) and Bland-Altman plots, respectively. Using a single UTR measure per runner, intrarater and interrater reliability (ICC2,1) was excellent (intrarater ICC2,1 range: 0.989-0.999; interrater ICC2,1 range: 0.990-0.995) and the minimum detectable change was 0.39-1.4 degrees. Measurements in 2D and 3D were significantly correlated for peak UTR (all r ≥ 0.986; all p-values < 0.001) and showed good agreement in Bland-Altman plots. Two-dimensional video-based measurement of transverse plane peak UTR is valid and reliable. UTR measurement may provide clinical insight into gait deviations in the transverse plane that alter angular momentum and increase risk for running-related injury. 2B.

Infographic. Remote running gait analysis

Physiotherapy has long followed a standard script. The patient is seen in-person at a clinic, a subjective history is taken and the physiotherapist completes a physical examination consisting of strength,...

Functional variability in the takeoff phase of one metre springboard forward dives.

In springboard diving consistency of body orientation at water entry is necessary for a good dive and is likely to be dependent on the consistency of conditions at takeoff. The aim of the present study was to investigate whether a diver modifies his technique from dive to dive during the board contact phase in order to be more consistent at takeoff in one metre springboard forward dives. Two-dimensional video analysis was used to calculate orientation and configuration angles of 12 forward pike dives and 12 forward 2½ somersault pike dives, performed by an international diver. A computer simulation model of a diver and springboard during board contact was used to obtain matching simulations of the performances and to calculate the rotation potential (angular momentum×flight time) for each dive. Simulations were used to determine the variation in conditions at maximum board depression arising from variation in touchdown conditions, and the variation in takeoff conditions arising from the variability in conditions at maximum board depression. A comparison of the simulated and performance variations implied that adjustments were made during the board contact phase for both the pike dives and the 2½ somersault pike dives. In the board depression phase, adjustments reduced the variability in the mass centre horizontal velocity at the lowest point. In the board recoil phase, adjustments reduced the variability in the horizontal velocity and rotation potential at takeoff.

Validity of Using Automated Two-Dimensional Video Analysis to Measure Continuous Sagittal Plane Running Kinematics.

Two-dimensional video analysis is commonly used to assess kinematics when three-dimensional motion capture is unavailable. However, videos are often assessed using manual digitization, which limits the ability to extract outcomes that require continuous data. Here, we introduced a method to collect continuous kinematic data in 2D using an inexpensive camera and an open-source automated marker tracking program. We tested the validity of this method by comparing 2D video analysis to 3D motion capture for measuring sagittal-plane running kinematics. Twenty uninjured participants ran on a treadmill for 1-min while lower extremity kinematics were collected simultaneously in 3D using a motion capture system and in 2D using a single digital camera, both at 120Hz. Knee, ankle, and foot angle at contact, peak knee flexion, knee flexion excursion, and knee-ankle flexion vector coding variability were computed using both the 3D and 2D kinematic data, and were compared using intraclass correlation coefficients and Bland-Altman plots. The agreement between collection methods was excellent for foot angle at contact and knee flexion excursion, good for ankle and knee angle at contact and knee-ankle vector coding variability, and moderate for peak knee flexion. However, Bland-Altman plots revealed significant differences between the 2D and 3D collection methods, which varied across study participants. These low-cost methods could be useful for collecting continuous sagittal plane running kinematics in non-laboratory settings.