2-Dimensional Video Research Articles

Single-Leg Squat as a Tool to Evaluate Young Athletes' Frontal Plane Knee Control.

To determine the agreement between 2-dimensional video analysis and subjective visual assessment by a physiotherapist in evaluating young athletes' knee control, and to determine the intrarater reliability and inter-rater reliability of the single-leg squat test. Frontal plane knee control was assessed by a physiotherapist on a 3-point scale. Frontal plane projection angles were calculated from video images. To determine the intrarater reliability, a physiotherapist reassessed 60 subjects' performances from a video. For the inter-rater reliability, 20 subjects were assessed by both the physiotherapist and a nonexperienced tester. The study continued for 3 test years. Research institute. Three hundred and seventy-eight floorball, basketball, ice hockey, and volleyball players. Knee control was assessed to be good, reduced, or poor. Agreement between the video analysis and subjectively assessed frontal plane knee control. Intrarater reliability and inter-rater reliability. There were statistically significant differences in the mean frontal plane knee angles between subjects rated as having "good," "reduced," or "poor" knee control. Intrarater reliability was fair for the assessments in the first year, moderate (dominant leg) and good (nondominant leg) for the second year, and very good (dominant leg) and good (nondominant leg) for the third year. Inter-rater reliability was fair/poor. This study suggests that by using the subjective assessment of the single-leg squat task, it is possible to detect differences in frontal plane knee control in young team sport athletes. The assessment can be considered to be reliable for clinical use when performed by an experienced tester.

DOES A ‘PREVENT INJURY AND ENHANCE PERFORMANCE’ PROGRAMME (PEP) CHANGE THE NEUROMUSCULAR CONTROL IN YOUNG FEMALE ACROBATIC GYMNASTS?

AimsThe primary aim of this interventional study was to identify if a PEP1 is an effective neuromuscular training intervention to change neuromuscular control (NMC) of the lower limb in young...

The effect of complexing agent on Ti alloy micro-arc oxidation(MAO) coatings in Ca-P electrolyte

Three new microarc (MAO) ceramic coatings were fabricated in the Ca-P electrolyte with three eco-friendly easily degradable complexing agent GA, TEA and EDTMPS and compared to that fabricated with the current common agent EDTA–2Na. A 3-Dimensional video microscope and scanning electro microscope were utilized to observe surface and cross-sectional morphology; the statistics of the coating surface were measured by the image software Image J × 2.0. Compositions of elements and phases were detected by the energy-dispersive X-ray spectroscopy and X-ray diffraction, respectively; X-ray photoelectron spectroscopy was further applied to provide more information about the components of the four complexing agents for MAO coatings surfaces. The surface morphologies show difference, which is a result of different quantity of melting metal during the treatment. The EDS results indicate that the elements compositions of the four MAO ceramic coatings are similar. The phases show little difference which is a result of the crystal transformation of TiO2 in different physical characteristic electrolytes. The biocative tests of four complexing agent MAO coatings shows good bioactive performance. The surface morphology of MAO coatings could meet the demand of biological implanting. Corrosion resistance properties are improved effectively in simulated body fluid (SBF). The wetting angles are less than 90 degrees, which indicates better solid-liquid affinity. After 28 days of sedimentation experiments in SBF, the white substance-carboxyl apatite (HA) generate on the surface of the coatings. The biological activities of the four MAO coating samples are demonstrated.

Is Soleus Muscle-Tendon-Unit Behavior Related to Ground-Force Application During the Sprint Start?

To describe the stretch-shortening behavior of ankle plantar-flexing muscle-tendon units (MTUs) during the push-off in a sprint start. Fifty-four male (100-m personal best: 9.58-12.07 s) and 34 female (100-m personal best: 11.05-14.00 s) sprinters were analyzed using an instrumented starting block and 2-dimensional high-speed video imaging. Analysis was performed separately for front and rear legs, while accounting for block obliquities and performance levels. The results showed clear signs of a dorsiflexion in the upper ankle joint (front block 15.8° ± 7.4°, 95% CI 13.2-18.2°; rear block 8.0° ± 5.7°, 95% CI 6.4-9.7°) preceding plantar flexion. When observed in their natural block settings, the athletes' block obliquity did not significantly affect push-off characteristics. It seems that the stretch-shortening-cycle-like motion of the soleus MTU has an enhancing influence on push-off force generation. This study provides the first systematic observation of ankle-joint stretch-shortening behavior for sprinters of a wide range of performance levels. The findings highlight the importance of reactive-type training for the improvement of starting performance. Nonetheless, future studies need to resolve the independent contributions of tendinous and muscle-fascicle structures to overall MTU performance.

Reliability of a Qualitative Video Analysis for Running.

Study Design Reliability study. Background Video analysis of running gait is frequently performed in orthopaedic and sports medicine practices to assess biomechanical factors that may contribute to injury. However, the reliability of a whole-body assessment has not been determined. Objective To determine the intrarater and interrater reliability of the qualitative assessment of specific running kinematics from a 2-dimensional video. Methods Running-gait analysis was performed on videos recorded from 15 individuals (8 male, 7 female) running at a self-selected pace (3.17 ± 0.40 m/s, 8:28 ± 1:04 min/mi) using a high-speed camera (120 frames per second). These videos were independently rated on 2 occasions by 3 experienced physical therapists using a standardized qualitative assessment. Fifteen sagittal and frontal plane kinematic variables were rated on a 3- or 5-point categorical scale at specific events of the gait cycle, including initial contact (n = 3) and midstance (n = 9), or across the full gait cycle (n = 3). The video frame number corresponding to each gait event was also recorded. Intrarater and interrater reliability values were calculated for gait-event detection (intraclass correlation coefficient [ICC] and standard error of measurement [SEM]) and the individual kinematic variables (weighted kappa [κw]). Results Gait-event detection was highly reproducible within raters (ICC = 0.94-1.00; SEM, 0.3-1.0 frames) and between raters (ICC = 0.77-1.00; SEM, 0.4-1.9 frames). Eleven of the 15 kinematic variables demonstrated substantial (κw = 0.60-0.799) or excellent (κw>0.80) intrarater agreement, with the exception of foot-to-center-of-mass position (κw = 0.59), forefoot position (κw = 0.58), ankle dorsiflexion at midstance (κw = 0.49), and center-of-mass vertical excursion (κw = 0.36). Interrater agreement for the kinematic measures varied more widely (κw = 0.00-0.85), with 5 variables showing substantial or excellent reliability. Conclusion The qualitative assessment of specific kinematic measures during running can be reliably performed with the use of a high-speed video camera. Detection of specific gait events was highly reproducible, as were common kinematic variables such as rearfoot position, foot-strike pattern, tibial inclination angle, knee flexion angle, and forward trunk lean. Other variables should be used with caution. J Orthop Sports Phys Ther 2016;46(7):556-561. Epub 6 Jun 2016. doi:10.2519/jospt.2016.6280.

Electromyographic Analysis of the Lower Limb Muscles in Low- and High-Handicap Golfers

Purpose: The aim of this study was to compare the electromyographic patterns of the lower limb muscles during a golf swing performed by low- and high-handicap golfers. Method: Ten golfers (5 low- and 5 high-handicap) performed 8 swings using a 7-iron. Surface electromyography (EMG) was recorded for the following lower limb muscles on both sides: biceps femoris, semitendinosus, gluteus maximus, vastus medialis and lateralis, rectus femoris, tibialis anterior, peroneus longus, and gastrocnemius medialis and lateralis. The golf-swing phases were determined by 3-dimensional high-speed video analysis. Results: Compared with the high-handicap golfers, the low-handicap golfers performed the forward swing with a shorter duration of the swing phases, with the exception of the late follow-through, where they exhibited longer duration. Considering the EMG patterns, the low-handicap golfers showed a tendency for the studied muscles to reach an activation peak earlier and presented statistically significant higher muscle activity in some of the lower limb muscles, mainly from the left side. Conclusion: Differences between low- and high-handicap golfers were found in the average duration of swing phases and in the activation level of the lower limbs, with more evidence on muscles from the left side.

Newly Identified Gait Patterns in Patients With Multiple Sclerosis May Be Related to Push-off Quality.

Limited walking ability is an important problem for patients with multiple sclerosis. A better understanding of how gait impairments lead to limited walking ability may help to develop more targeted interventions. Although gait classifications are available in cerebral palsy and stroke, relevant knowledge in MS is scarce. The aims of this study were: (1) to identify distinctive gait patterns in patients with MS based on a combined evaluation of kinematics, gait features, and muscle activity during walking and (2) to determine the clinical relevance of these gait patterns. This was a cross-sectional study of 81 patients with MS of mild-to-moderate severity (Expanded Disability Status Scale [EDSS] median score=3.0, range=1.0-7.0) and an age range of 28 to 69 years. The patients participated in 2-dimensional video gait analysis, with concurrent measurement of surface electromyography and ground reaction forces. A score chart of 73 gait items was used to rate each gait analysis. A single rater performed the scoring. Latent class analysis was used to identify gait classes. Analysis of the 73 gait variables revealed that 9 variables could distinguish 3 clinically meaningful gait classes. The 9 variables were: (1) heel-rise in terminal stance, (2) push-off, (3) clearance in initial swing, (4) plantar-flexion position in mid-swing, (5) pelvic rotation, (6) arm-trunk movement, (7) activity of the gastrocnemius muscle in pre-swing, (8) M-wave, and (9) propulsive force. The EDSS score and gait speed worsened in ascending classes. Most participants had mild-to-moderate limitations in walking ability based on their EDSS scores, and the number of walkers who were severely limited was small. Based on a small set of 9 variables measured with 2-dimensional clinical gait analysis, patients with MS could be divided into 3 different gait classes. The gait variables are suggestive of insufficient ankle push-off.

Correlation Between Arthroscopy Simulator and Video Game Performance: A Cross-Sectional Study of 30 Volunteers Comparing 2- and 3-Dimensional Video Games

To investigate the association between arthroscopy simulator performance and video game skills. This study compared the performances of 30 volunteers without experience performing arthroscopies in 3 different tasks of a validated virtual reality knee arthroscopy simulator with the video game experience using a questionnaire and actual performances in 5 different 2- and 3-dimensional (D) video games of varying genres on 2 different platforms. Positive correlations between knee arthroscopy simulator and video game performances (ρ= 0.63, P< .001) as well as experiences (ρ= 0.50, P= .005) were found. The strongest correlations were found for the task of catching (hooking) 6 foreign bodies (virtual rings; "triangulation") and the dribbling performance in a sports game and a first-person shooter game, as well as the meniscus resection and a tile-matching puzzle game (all ρ ≥ 0.60, P < .001). No correlations were found for any of the knee arthroscopy simulator tasks and a strategy game. Although knee arthroscopy performances do not correlate with 2-D strategy video game skills, they show a correlation with 2-D tile-matching puzzle games only for easier tasks with a rather limited focus, and highly correlate with 3-D sports and first-person shooter video games. These findings show that experienced and good 3-D gamers are better arthroscopists than nonexperienced and poor 3-D gamers. Level II, observational cross-sectional study.

Histology Atlas of the Developing Mouse Hepatobiliary Hemolymphatic Vascular System with Emphasis on Embryonic Days 11.5-18.5 and Early Postnatal Development.

A critical event in embryo development is the proper formation of the vascular system, of which the hepatobiliary system plays a pivotal role. This has led researchers to use transgenic mice to identify the critical steps involved in developmental disorders associated with the hepatobiliary vascular system. Vascular development is dependent upon normal vasculogenesis, angiogenesis, and the transformation of vessels into their adult counterparts. Any alteration in vascular development has the potential to cause deformities or embryonic death. Numerous publications describe specific stages of vascular development relating to various organs, but a single resource detailing the stage-by-stage development of the vasculature pertaining to the hepatobiliary system has not been available. This comprehensive histology atlas provides hematoxylin & eosin and immunohistochemical-stained sections of the developing mouse blood and lymphatic vasculature with emphasis on the hepatobiliary system between embryonic days (E) 11.5-18.5 and the early postnatal period. Additionally, this atlas includes a 3-dimensional video representation of the E18.5 mouse venous vasculature. One of the most noteworthy findings of this atlas is the identification of the portal sinus within the mouse, which has been erroneously misinterpreted as the ductus venosus in previous publications. Although the primary purpose of this atlas is to identify normal hepatobiliary vascular development, potential embryonic abnormalities are also described.

삼차원 가상현실 운동 프로그램이 노인의 시공간적 보행변수에 미치는 효과

PURPOSE: This study was conducted to investigate the effect of the virtual reality training (VRT) using 3-dimensional video gaming technology on spatiotemporal gait parameters in older adults. METHODS: The study participants were divided into two groups: the VRT group and the control group. Those in the VRT group were enrolled in a VRT, which was conducted for 60 min per day, two times a week, during the 6-week research. The Wii-Fit balance board game was used for the VRT intervention. The VRT consisted of 6 different types of games, namely, jogging, swordplay, ski jump, hula hoop, tennis, and step dance. A 3-dimensional TV was used for 3-dimensional display. Participants in both the groups received 3 sessions of fall prevention education, at the first, third, and fifth weeks. Their gait parameters were measured by using OptoGait. RESULTS: After 6 weeks of the VRT, the spatial gait parameters of the participants, that is stride length and step length, were significantly improved compared with those of the control group participants (p

The usefulness of 3-dimensional endoscope systems in endoscopic surgery.

The image quality and performance of 3-dimensional video image systems has improved along with improvements in technology. However, objective evaluation on the usefulness of 3-dimensional video image systems is insufficient. Therefore, we decided to investigate the usefulness of 3-dimensional video image systems using the objective endoscopic surgery technology evaluating apparatus that we have developed, the Hiroshima University Endoscopic Surgical Assessment Device (HUESAD). The participants were 28 student volunteers enrolled in Hiroshima University (17 men and 11 women, age: median 22.5, range 20-25), with no one having experienced endoscopic surgery training. Testing was carried out by dividing the subjects into two groups to initially carry out HUESAD with 2-dimensional video imaging (N=14) and with 3-dimensional video imaging (N=14). Questionnaires were carried out along with the investigation regarding both 2-dimensional and 3-dimensional video imaging. The task was carried out for approximately 15min regarding both 2-dimensional and 3-dimensional video imaging. Lastly, the Mental Rotation Test, which is a standard space perception ability test, was used to evaluate the space perception ability. No difference was observed in the nauseous and uncomfortable feeling of practitioners between the two groups. Regarding smoothness, no difference was observed between 2-dimensional and 3-dimensional video imaging (p=0.8665). Deviation (space perception ability) and approaching time (accuracy) were significantly lower with 3-dimensional video imaging compared to 2-dimensional video imaging. Moreover, the approaching time (accuracy) significantly improved in 3-dimensional video imaging compared to 2-dimensional video imaging in the group with low space perception ability (p=0.0085). Objective evaluation using HUESAD and subjective evaluation by questionnaire revealed that endoscopic surgery techniques significantly improved in 3-dimensional video imaging compared to 2-dimensional video imaging. Moreover, it is believed that this effect is more effective in people with low space perception ability and beginner students.

Between Days Reliability of 2D Video Analysis during Landing while Undertaking a Crossover Hop Test

The Crossover Hop Test is a Functional Performance Test (FPT), which is used to demonstrate the leg muscles strength and performance, and evaluate symmetry between lower limbs, while evaluating the hop distance. Hop tests have been shown to be reliable for both injured and active subjects. The current study aims to establish the between days reliability of 2-Dimensional (2D) video analysis measuring knee valgus angles (frontal plane projection angle; FPPA) during each landing whilst undertaking a crossover hop test. Nine recreational male athletes (age 33.89 ± 3.96, height 170 ± 8.59 cm, weight 86.94 ± 20.86 kg) participated in the experiment. Each individual performed three repetitions of the cross over hop test, for both legs, and then repeated the same test seven days later. Results showed from the four landings that the first and third, for both legs demonstrated excellent Intraclass Correlation Coefficient (ICC) values for FPPA between days, while good to excellent ICC values for FPPA of the second landing and moderate ICC values for FPPA for the fourth. Standard Error Measurement (SEM) scores ranged from 1.04° to 2.42° for the right FPPA during the four landings, while the range of SEM values for the left FPPA were from 0.82° to 2.08°. The landing strategy adopted by participants, as defined by FPPA, would appear to be consistent between sessions. Hence, researchers and clinicians will be able to use crossover hop tests, which incorporate 2D video analysis, to assess simultaneously the limbs' performance functionality and the valgus angle of the knee. Therefore, this will save the athletes' and researchers' time, which will subsequently reduce the amount of fatigue resulting from over testing.

The morphology, structure and composition of microarc oxidation (MAO) ceramic coating in Ca-P electrolyte with complexing agent EDTMPS and interpretation hypothesis of MAO process

A new MAO ceramic coating was fabricated in Ca-P electrolyte with a eco-friendly easily degradable complexing agent EDTMPS instead of current common EDTA-2Na. A 3-Dimensional video microscope and SEM were utilized to observe surface and cross-section morphology, and statistics ofcoating surface were measured by image software ImageJx 2.0. Elements and phases compositions were detected by EDS and XRD respectively, and XPS was further undertaken to provide more information about the components of the two complexing agents MAO coatings surfaces. The results indicate that the elements and phases composition of the two MAO ceramic coatings are similar. The surface morphologies show the difference, which is a result of more melting metal during the treatment in EDTMPS electrolyte compared with EDTA-2Na. The results of recent studies of discharge and discharge plasma in low temperature liquid and thermodynamics were introduced into the establishment of MAO process models which was divided into three parts: cusp area, even area and sunk area. Active particles, O2, free radical •OH, free radical H2O2, free radical •H brought by discharge and discharge plasma play a significant effect on the phase transformation, electrolyte elements diffusion from electrolyte to coating and substrate and chemical reactions. Crater shape of surface morphology is mainly attributed to the sharply increasing pressure with the decreasing of temperature. Finally, a interpretation of MAO process based on the theory of thermodynamics, and discharge plasma in low temperature liquid was developed.

Short communication: Measuring feed volume and weight by machine vision

Individual dairy cow feed intake is closely related to the health and productive output of each cow, with healthy cows generally eating more feed than unhealthy cows. Incorporating the use of an automated system to monitor feed consumption for each cow may be beneficial for dairy farm management. This study examined the use of an inexpensive 3-dimensional video camera to measure feed volume, from which we derived feed weight. Proof-of-concept testing was conducted to determine the effectiveness and capability of the machine vision feed-scanning system and its possible use in feed intake monitoring. Such systems are ideal because they do not impede the workflow of the farm or interrupt feeding behavior. This is an improvement over existing systems that are labor and cost intensive. Our conducted experiments involve measuring feed volume at known weights, up to 22.68kg, with the resulting volume and weight values analyzed by means of linear and quadratic least squares t-test regression analysis. The effects of feed positioning in the bin and near-range sensor limitations were also examined. The results showed that an estimation of feed weight from 3-dimensional scan of volume measurements could be made to within 0.5kg of the physically measured feed weight using a digital scale. Future efforts will focus on extending this work to active bunks with multiple cows eating throughout the day and testing total mixed rations of varied composition.

Dynamic texture recognition by aggregating spatial and temporal features via ensemble SVMs

A dynamic texture (DT) refers to a sequence of images that exhibit spatial and temporal regularities. The modeling of DTs plays an important role in many video-related vision tasks, where the main difficulty lies in fact how to simultaneously depict the spatial and temporal aspects of DTs. While unlike the modeling of DTs, tremendous achievements have been recently reported on static texture modeling.This paper addresses the problem of dynamic texture recognition by aggregating spatial and temporal texture features via an ensemble SVM scheme, and bypassing the difficulties of simultaneously spatio-temporal description of DTs. More precisely, firstly, by considering a 3-dimensional DT video as a stack 2-dimensional static textures, we exploit the spatial texture features of single frame to combine different aspects of spatial structures, followed by randomly selecting several frames of the DT video in the time augmentation process. Secondly, in order to incorporate temporal information, the naive linear dynamic system (LDS) model is used to extract dynamics of DTs in temporal domain. Finally, we aggregate these spatial and temporal cues via an ensemble SVM architecture. We have experimented not only on several common dynamic texture datasets, but also on two challenging dynamic scene datasets. The results show that the proposed scheme achieves the state-of-the-art performances on the recognition of dynamic textures and dynamic scenes. Moreover, our approach offers a simple and general way to aggregate any spatial and temporal features into the task of dynamic texture recognition.

PH值对304不锈钢在3.5%NaCl溶液中点蚀过程的影响

Effect of pH values on pitting dynamics and morphology of single pits of 304 stainless steel in 3.5%NaCl solution was studied by means of potentiostatic polarization and 3-dimensional video microscope. The results showed that the pitting current, the growth rate of pit volume, the pit depth and pit mouth diameter of single pits increase with the decreasing pH in a range 1 to 14 by applied potential of 0.15 Vvs SCE. In solutions with the same pH, the growth rate of pit depth increas- es with time, while the growth rate of pit mouth diameter decreases with time. In solutions with dif- ferent pH, the growth of single pit is controlled by the diffusion through corrosion products. There exists lacy cover on the wall of pit mouth, and the integrity of the lacy cover declines with the in- crease of pH.

Gait Retraining for Injured and Healthy Runners Using Augmented Feedback: A Systematic Literature Review.

Systematic literature review. This review sought to determine the efficacy of real-time visual and/or auditory feedback for modifying kinematics and kinetics during running gait. Real-time visual and auditory feedback has gained popularity in the clinical and research settings. Rehabilitation time and injury prevention may be improved when clinicians are able to modify running mechanics in a patient population. A thorough search of PubMed, CINAHL, and Web of Science from 1989 to January 2015 was performed. The search sought articles that examined real-time visual or auditory feedback for the purposes of modifying kinematics or kinetics in injured or healthy runners. Study design and methodological quality were rated using a 20-point scale. Ten studies were identified for inclusion in the review, 2 of high and 8 of moderate methodological quality. There was a consensus in the literature that the use of real-time feedback is effective in reducing variables related to ground reaction forces, as well as in positively modifying previously identified risky lower extremity kinematic movement patterns in healthy runners and those with patellofemoral pain and chronic exertional compartment syndrome. No one method of feedback was identified as being superior. Mirror and 2-dimensional video feedback were identified as potential methods for running-gait modification in a clinical setting. In conjunction with traditional therapeutic interventions, real-time auditory and visual feedback should be considered for treating injured runners or addressing potentially injurious running mechanics in a healthy population.

Ka-밴드 구름레이더 자료품질 및 구름통계 기초연구

The Ka-band cloud radar (KCR) has been operated by the National Institute of Meteorological Research (NIMR) of Korea Meteorological Administration (KMA) at Boseong National Center for Intensive Observation of severe weather since 2013. Evaluation of data quality is an essential process to further analyze cloud information. In this study, we estimate the measurement error and the sampling uncertainty to evaluate data quality. By using vertically pointing data, the statistical uncertainty is obtained by calculating the standard deviation of each radar parameter. The statistical uncertainties decrease as functions of sampling number. The statistical uncertainties of horizontal and vertical reflectivities are identical (0.28 dB). On the other hand, the statistical uncertainties of Doppler velocity (spectrum width) are 2.2 times (1.6 times) larger at the vertical channel. The reflectivity calibration of KCR is also performed using X-band vertically pointing radar (VertiX) and 2-dimensional video disdrometer (2DVD). Since the monitoring of calibration values is useful to evaluate radar condition, the variation of calibration is monitored for five rain events. The average of calibration bias is 10.77 dBZ and standard deviation is 3.69 dB. Finally, the statistical characteristics of cloud properties have been investigated during two months in autumn using calibrated reflectivity. The percentage of clouds is about 26% and 16% on September to October. However, further analyses are required to derive general characteristics of autumn cloud in Korea.

Development and Validation of a Novel Robotic Procedure Specific Simulation Platform: Partial Nephrectomy

We developed a novel procedure specific simulation platform for robotic partial nephrectomy. In this study we prospectively evaluate its face, content, construct and concurrent validity. This hybrid platform features augmented reality and virtual reality. Augmented reality involves 3-dimensional robotic partial nephrectomy surgical videos overlaid with virtual instruments to teach surgical anatomy, technical skills and operative steps. Advanced technical skills are assessed with an embedded full virtual reality renorrhaphy task. Participants were classified as novice (no surgical training, 15), intermediate (less than 100 robotic cases, 13) or expert (100 or more robotic cases, 14) and prospectively assessed. Cohort performance was compared with the Kruskal-Wallis test (construct validity). Post-study questionnaire was used to assess the realism of simulation (face validity) and usefulness for training (content validity). Concurrent validity evaluated correlation between virtual reality renorrhaphy task and a live porcine robotic partial nephrectomy performance (Spearman's analysis). Experts rated the augmented reality content as realistic (median 8/10) and helpful for resident/fellow training (8.0-8.2/10). Experts rated the platform highly for teaching anatomy (9/10) and operative steps (8.5/10) but moderately for technical skills (7.5/10). Experts and intermediates outperformed novices (construct validity) in efficiency (p=0.0002) and accuracy (p=0.002). For virtual reality renorrhaphy, experts outperformed intermediates on GEARS metrics (p=0.002). Virtual reality renorrhaphy and in vivo porcine robotic partial nephrectomy performance correlated significantly (r=0.8, p <0.0001) (concurrent validity). This augmented reality simulation platform displayed face, content and construct validity. Performance in the procedure specific virtual reality task correlated highly with a porcine model (concurrent validity). Future efforts will integrate procedure specific virtual reality tasks and their global assessment.

Lower Extremity Biomechanics and Self-Reported Foot-Strike Patterns Among Runners in Traditional and Minimalist Shoes

Context : The injury incidence rate among runners is approximately 50%. Some individuals have advocated using an anterior-foot-strike pattern to reduce ground reaction forces and injury rates that they attribute to a rear-foot-strike pattern. The proportion of minimalist shoe wearers who adopt an anterior-foot-strike pattern remains unclear. Objective : To evaluate the accuracy of self-reported foot-strike patterns, compare negative ankle- and knee-joint angular work among runners using different foot-strike patterns and wearing traditional or minimalist shoes, and describe average vertical-loading rates. Design : Descriptive laboratory study. Setting : Research laboratory. Patients or Other Participants : A total of 60 healthy volunteers (37 men, 23 women; age = 34.9 ± 8.9 years, height = 1.74 ± 0.08 m, mass = 70.9 ± 13.4 kg) with more than 6 months of experience wearing traditional or minimalist shoes were instructed to classify their foot-strike patterns. Intervention(s) : Participants ran in their preferred shoes on an instrumented treadmill with 3-dimensional motion capture. Main Outcome Measure(s) : Self-reported foot-strike patterns were compared with 2-dimensional video assessments. Runners were classified into 3 groups based on video assessment: traditional-shoe rear-foot strikers (TSR; n = 22), minimalist-shoe anterior-foot strikers (MSA; n = 21), and minimalist-shoe rear-foot strikers (MSR; n = 17). Ankle and knee negative angular work and average vertical-loading rates during stance phase were compared among groups. Results : Only 41 (68.3%) runners reported foot-strike patterns that agreed with the video assessment (κ = 0.42, P < .001). The TSR runners demonstrated greater ankle-dorsiflexion and knee-extension negative work than MSA and MSR runners (P < .05). The MSA (P < .001) and MSR (P = .01) runners demonstrated greater ankle plantar-flexion negative work than TSR runners. The MSR runners demonstrated a greater average vertical-loading rate than MSA and TSR runners (P < .001). Conclusions : Runners often cannot report their foot-strike patterns accurately and may not automatically adopt an anterior-foot-strike pattern after transitioning to minimalist running shoes.