Dimensional Motion Research Articles

Impact Of Limb And Total Body Composition On Drop Vertical Jump Landing Kinematics

Lower limbs containing elevated levels of adipose tissue exhibit diminished quadricep strength and power. Deficits in quadriceps function negatively influence sagittal knee mechanics during drop vertical jumping (DVJ) maneuvers. It is poorly understood how measures of limb and systemic composition impact landing performance and injury risk. PURPOSE: Determine the relationship between composition and sagittal knee kinematics during landing from a DVJ. METHODS: Thirty-six female (171.0 ± 7.6 cm; 66.5 ± 7.6 kg; 22.7 ± 1.8BMI) collegiate volleyball and soccer athletes participated in this study. Biomechanical variables of interest include sagittal knee angle (KA) obtained at two different points during landing using 3-dimensional marker-less motion capture during DVJ maneuvers. These two points were initial contact (IC) and the ending of the landing phase, defined where the center of gravity was at its lowest point (MIN). Higher negative sagittal angle values are indicative of greater knee flexion. Dual x-ray absorptiometry (DXA) was used to compute total body fat percentage (BF%) and bilateral limb lean mass (LLM). LLM was normalized to the total mass of the limb. Associations between landing biomechanics and compositional measures were analyzed via Pearson Product Moment correlations. RESULTS: KA at MIN in the left (-92.8 ± 8.9°) and right leg (-92.4 ± 9.5°) were associated with BF% (27.5 ± 4.3%) (Right: r = 0.430, p = 0.009; Left: r = 0.432, p = 0.008) and LLM (Right: 64.3 ± 4.3% limb mass; Left: 64.0 ± 4.6% limb mass) (Right: r = -0.416, p = 0.012; Left: r = -0.410, p = 0.013). At IC, right leg (-23.7 ± 8.4°) KA had a weak relationship to BF% (r = 0.390, p = 0.019) and LLM (r = -0.364, p = 0.029). Relationships between KA at IC in the left leg (-26.5 ± 8.3°) and BF% (r = 0.289, p = 0.088) and LLM (r = -0.311, p = 0.065) were not significant. CONCLUSIONS: The relationship between BF% and LLM and sagittal KA during DVJ landing indicate that greater LLM and lower BF% may be better for injury risk and performance. Lesser knee flexion range of motion during landing may be caused by inhibited capacity to attenuate landing forces during sport performance. Greater adipose tissue within the limb and systemically may negatively influence injury risk by reducing the ability to adequately absorb forces when landing during an athletic task.

Correlating Biomechanical Gait Analysis With Patient-Reported Outcomes After Hip Arthroscopy for Femoroacetabular Impingement Syndrome.

Background:Postoperative biomechanics after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) are an outcome of interest, but correlation with patient-reported outcomes (PROs) remains unclear.Purpose/Hypothesis:The purpose of this study was to assess the correlation between changes in hip biomechanics in FAIS patients after hip arthroscopy and changes in PRO scores. We hypothesized that gait analysis would demonstrate significant correlations between pre- and postoperative changes in biomechanics and changes in PRO scores.Study Design:Descriptive laboratory study.Methods:FAIS patients without dysplasia or arthritis who underwent primary hip arthroscopy for labral repair and femoroplasty underwent preoperative and 1-year postoperative 3-dimensional motion tracking and biomechanical testing during normal gait. Joint kinematics calculated included flexion/extension (sagittal plane), abduction/adduction (frontal plane), and internal/external rotation (transverse plane). Peak hip angles and moments were compared between baseline and 1-year postoperative measures. At baseline, 1-year, and 2-year postoperatively, patients completed the following PRO surveys: 12-Item Short Form Health Survey (SF-12), modified Harris Hip Score (mHHS), and Hip disability and Osteoarthritis Outcome Score (HOOS). Joint kinematics that significantly improved 1 year after surgery were assessed for correlations with PRO scores.Results:A total of 10 patients (12 hips) were enrolled prospectively. PROs significantly improved at 1 and 2 years postoperatively compared with baseline values for HOOS, mHHS, and SF-12 Physical Component Score, with all patients achieving the minimal clinically important difference (MCID) on the HOOS Sport/Recreation and Quality of Life subscales. From preoperatively to 1-year postoperatively, significant improvements were seen in peak hip abduction angle (from −2.3° ± 1.8° to −4.6° ± 1.8°; P = .0058) and peak hip extension moment (from −1.03 ± 0.19 to −0.85 ± 0.20 N·m/kg; P = .014); however, there were no significant correlations between these changes and the pre- to postoperative changes on any PRO scores.Conclusion:Gait analysis of FAIS patients after hip arthroscopy demonstrated small, albeit significant, changes in postoperative hip kinetics and kinematics; however, these changes did not correlate with the large, clinically significant improvements in PROs at 1 year after surgery.Clinical Relevance:The results of this study suggest that the degree of improvement in short-term PROs after hip arthroscopy for FAIS may not be related to small changes in biomechanics postoperatively.

The influence of excessive ipsilateral trunk tilt on upper-extremity throwing mechanics: a newly characterized parameter for biomechanical evaluation in high school and professional pitchers.

Although contralateral trunk tilt has been recognized, the phenomenon of excessive ipsilateral trunk tilt, often observed during earlier portions of the pitch, has not been explored as a potential correlate with throwing-arm kinetics among baseball pitchers. The purpose of this study was to evaluate kinetic and kinematic parameters among high school and professional pitchers related to excessive ipsilateral and contralateral trunk tilt. Professional and high school pitchers were assessed with a 3-dimensional motion capture system (480 Hz) while pitching. Pitchers were grouped as follows: excessive ipsilateral tilt at foot contact (FC), neutral, or excessive contralateral tilt at ball release (BR). Trunk and shoulder kinematics as well as throwing-arm kinetics were compared between subgroups via post hoc regression analysis. Professional pitchers (n=287) had significantly higher ipsilateral trunk tilt at FC (P<.001) than high school pitchers (n=59). High school pitchers with excessive contralateral trunk tilt at BR experienced significantly higher shoulder superior force (27.0%±7.4% body weight [BW] vs. 17.6%±5.1% BW, P<.001) and shoulder anterior force (39.6%±8.2% BW vs. 35.7%±5.4% BW, P<.001) compared with the ipsilateral trunk tilt cohort but had comparable ball velocity (30.2±3.2 m/s vs. 30.4±2.1 m/s, P=.633). For professionals, for every 10° increase in ipsilateral trunk tilt at FC, ball velocity increased by 0.2 m/s (B = 0.02, β = 0.07, standard error [SE] = 0.005, P= .010) whereas elbow varus torque decreased by 0.1% BW × height (B = -0.01, β = -0.08, SE = 0.002, P<.001) and shoulder internal rotation torque decreased by 0.1% BW × height (B = -0.01, β = -0.07, SE = 0.002, P= .005). High school and professional pitchers with excessive ipsilateral trunk tilt at FC consistently demonstrated significantly decreased throwing-arm kinetics (shoulder anterior force and shoulder superior force for high school pitchers and shoulder internal rotation torque and elbow varus torque for professional pitchers) compared with pitchers with excessive contralateral trunk tilt at BR, with equivalent ball velocity. In addition, professional pitchers appeared to engage in significantly greater ipsilateral trunk tilt during early portions of the pitch when compared with high school pitchers, which may represent a kinetically favorable method adopted by pitchers at higher playing levels to maintain adequate ball velocity while concomitantly minimizing throwing-arm kinetics.

Investigating The Effects Of 3-Dimensional Motion Object Tracking (3D-MOT) Training On In-game College Soccer Performance

Investigating The Effects Of 3-Dimensional Motion Object Tracking (3D-MOT) Training On In-game College Soccer Performance

Sloshing dynamics estimation for liquid-filled containers performing 3-dimensional motions: modeling and experimental validation

Many industrial applications require the displacement of liquid-filled containers on planar paths (namely, paths on a horizontal plane), by means of linear transport systems or serial robots. The movement of the liquid inside the container, known as sloshing, is usually undesired, thus there is the necessity to keep under control the peaks that the liquid free-surface exhibits during motion. This paper aims at validating a model for estimating the liquid sloshing height, taking into account 2-dimensional motions of a cylindrical container occurring on a horizontal plane, with accelerations up to 9.5 m/s2. This model can be exploited for assessment or optimization purposes. Experiments performed with a robot following three paths, each one of them with different motion profiles, are described. Comparisons between experimental results and model predictions are provided and discussed.Finally, the previous formulation is extended in order to take into account the addition of a vertical acceleration, up to 5 m/s2. The resulting 3-dimensional motions are experimentally validated to prove the effectiveness of the extended technique.

Reliability and validity of 2-dimensional video analysis for a running task: A systematic review

ObjectiveEvaluate the reliability and validity of 2-dimensional (2D) video-based motion analysis during running. MethodsA systematic search of MEDLINE, Cochrane Library, EMBASE, CINAHL, PEDro, SPORTDiscus, and IEEE Xplore was conducted in March 2020 and updated in May 2021. We included studies assessing reliability and/or validity of 2D video-based motion analysis (gold standard: 3D motion analysis) during running. Results11 studies (251 runners; mean age range: 18.7–37.0 years; 57.4% female; 63.7% injury-free) met inclusion criteria. Eight studies examined kinematics of the pelvis/hip, eight of the knee, and six of the ankle/foot. Low-to-moderate risk of bias was present in all studies. Heterogeneous study designs, measurement methods, and statistical approaches across studies precluded statistical synthesis. Intrarater reliability [Interclass correlation coefficient (ICC) range: 0.56–1.00; kappa range: 0.49–0.81] was better than interrater reliability (ICC range: 0.31–1.00; kappa range 0.00–0.85). ICC values for validity were poor to good (0.06–0.89). One study examining foot strike pattern found good to excellent validity (using Gwet AC statistics) when movement kinematics were categorized. ConclusionsA wide range of methods were reported in 2D video-based motion analysis of joint angular kinematics during a running task. Further research to develop standardized 2D video-based motion analysis for running is needed. Categorizing movement patterns may be more useful than angularly quantifying joint kinematics.

Fine-scale movement of northern Gulf of Mexico red snapper and gray triggerfish estimated with three-dimensional acoustic telemetry

Red snapper and gray triggerfish are ecologically, economically, and culturally important reef fishes in the northern Gulf of Mexico (nGOM). Scientists and managers have sought to understand the effects of artificial reefs on reef fish ecology by focusing on fish residency and movement at artificial reefs with less attention paid to broader spatial and temporal patterns in reef fish movements among a seascape of artificial reefs and other natural habitats. We used novel large-scale (> 15 km2) geopositioning acoustic telemetry arrays to track the 3-dimensional movements of tagged red snapper (n = 59) and gray triggerfish (n = 15) among multiple nGOM artificial reefs up to 333 days. Tagged fish moved frequently among artificial reefs and had shorter residence times at the release reef (43 days for red snapper and 3 days for gray triggerfish) than reported in previous studies. Both species displayed high individual variability in movement dynamics, as well as seasonally variable diel patterns of habitat use, height above bottom, and distance to reefs, which may have been driven by dynamic influences of predation risk, physiological constraints, or foraging over time and space. The wider seascape view revealed in this study demonstrates the importance of including multiple artificial reefs over long timescales to capture individual, spatial, and temporal variability in reef fish movement.

Predicting ACL Injury Using Machine Learning on Data From an Extensive Screening Test Battery of 880 Female Elite Athletes

Background: Injury risk prediction is an emerging field in which more research is needed to recognize the best practices for accurate injury risk assessment. Important issues related to predictive machine learning need to be considered, for example, to avoid overinterpreting the observed prediction performance. Purpose: To carefully investigate the predictive potential of multiple predictive machine learning methods on a large set of risk factor data for anterior cruciate ligament (ACL) injury; the proposed approach takes into account the effect of chance and random variations in prediction performance. Study Design: Case-control study; Level of evidence, 3. Methods: The authors used 3-dimensional motion analysis and physical data collected from 791 female elite handball and soccer players. Four common classifiers were used to predict ACL injuries (n = 60). Area under the receiver operating characteristic curve (AUC-ROC) averaged across 100 cross-validation runs (mean AUC-ROC) was used as a performance metric. Results were confirmed with repeated permutation tests (paired Wilcoxon signed-rank-test; P < .05). Additionally, the effect of the most common class imbalance handling techniques was evaluated. Results: For the best classifier (linear support vector machine), the mean AUC-ROC was 0.63. Regardless of the classifier, the results were significantly better than chance, confirming the predictive ability of the data and methods used. AUC-ROC values varied substantially across repetitions and methods (0.51-0.69). Class imbalance handling did not improve the results. Conclusion: The authors’ approach and data showed statistically significant predictive ability, indicating that there exists information in this prospective data set that may be valuable for understanding injury causation. However, the predictive ability remained low from the perspective of clinical assessment, suggesting that included variables cannot be used for ACL prediction in practice.

MMAP-04 CYTOTOXIC, TUMOR-HOMING INDUCED NEURAL STEM CELLS AS AN ADJUVANT TO RADIATION IN THE TREATMENT OF NON-SMALL CELL LUNG CANCER LEPTOMENINGEAL METASTASES

INTRODUCTIONNon-small cell lung cancer (NSCLC) is the most common cancer to spread to the brain, and spread to the leptomeninges is particularly devastating, with a median survival of only months. While radiation may offer symptomatic relief, new adjuvant therapies are needed for more durable tumor kill. Spheroidal, human induced neural stem cells (hiNeuroS) transdifferentiated from fibroblasts are inherently tumoritropic. When engineered to secrete the cytotoxic protein TRAIL, they provide the potential for a personalized, targeted approach to NSCLC leptomeningeal metastases. METHODShiNeuroS-TRAIL in vivo efficacy was determined by tracking the progression and survival of mice with NSCLC leptomeningeal tumors treated with intracerebroventricular hiNeuroS, radiation, or both. To determine the impact of radiation on the tumor tropism of hiNeuroS, we performed 2-dimensional motion assays on hiNeuroS with and without the presence of NSCLC pre- and post-radiation. Migrational capacity in vivo was determined by infusing hiNeuroS into the lateral ventricles of mice with established NSCLC tumors and monitoring hiNeuroS accumulation using post-mortem fluorescent analysis. RESULTS/CONCLUSIONMice treated with the combination of hiNeuroS-TRAIL and 2 Gy showed a significantly reduced mean tumor signal (2.7%) compared to controls (100%) or 2 Gy-only (54.9%). Mice treated with 2 Gy alone showed no significant survival difference compared to controls. Both combination and hiNeuroS-TRAIL-only-treated mice showed a significant improvement in median survival compared to controls (36.6% and 46.3% improvement, respectively). hiNeuroS showed enhanced directionality and displacement in the presence of NSCLC in 2-dimensional motion assays, indicating directional migration, and they maintained this ability following exposure to radiation. Co-localization of hiNeuroS with NSCLC was also observed in vivo. These results suggest the potential of hiNeuroS-TRAIL as a powerful adjuvant to radiation in the treatment of leptomeningeal NSCLC.

The Criterion Validity and Between-Day Reliability of the Perch for Measuring Barbell Velocity During Commonly Used Resistance Training Exercises.

Weakley, J, Munteanu, G, Cowley, N, Johnston, R, Morrison, M, Gardiner, C, Pérez-Castilla, A, and García-Ramos, A. The criterion validity and between-day reliability of the Perch for measuring barbell velocity during commonly used resistance training exercises. J Strength Cond Res 37(4): 787-792, 2023-This study aimed to assess the criterion validity and between-day reliability (accounting for technological and biological variability) of mean and peak concentric velocity from the Perch measurement system. On 2 testing occasions, 16 subjects completed repetitions at 20, 40, 60, 80, 90, and 100% of 1-repetition maximum in the free-weight barbell back squat and bench press. To assess criterion validity, values from the Perch and a 3-dimensional motion capture system (criterion) were compared. Technological variability was assessed by determining whether the differences between the Perch and criterion for each load were comparable for both testing sessions, whereas between-day reliability with both technological and biological variability was calculated from Perch values across days. Generalized estimating equations were used to calculate R2 and root mean square error, whereas Bland-Altman plots assessed magnitude of difference between measures. To support monitoring of athletes over time, standard error of measurement and minimum detectable changes (MDC) were calculated. There was excellent agreement between the Perch and criterion device, with mean velocity in both exercises demonstrating a mean bias ranging from -0.01 to 0.01 m·s -1 . For peak velocity, Perch underestimated velocity compared with the criterion ranging from -0.08 to -0.12 m·s -1 for the back squat and -0.01 to -0.02 m·s -1 for the bench press. Technological variability between-days were all less than the MDC. These findings demonstrate that the Perch provides valid and reliable mean and peak concentric velocity outputs across a range of velocities. Therefore, practitioners can confidently implement this device for the monitoring and prescription of resistance training.

Prediction of adsorption isotherms of C3H6/C3H8 on hierarchical porous HP–Cu–BTC

The isotherms of C3H6 and C3H8 on three distinct HP–Cu–BTCs were determined using the static volumetric capacity technique across the pressure range 0–100 kPa, and the resulting experimental data set was regressed using the dual–site sips (DSS) model. The kinetics and thermodynamics of C3H6 and C3H8 on HP–Cu–BTCs were studied. The results show that the adsorption kinetics of the three samples conform to the pseudo–first–order kinetic model, indicating that the adsorption process of the HP–Cu–BTCs samples is the adsorption process with physical adsorption as the control step. The thermodynamic analysis results show that the adsorption of propylene and propane on the surface of HP–Cu–BTCs are a spontaneous exothermic process, because the transition of propylene and propane from three–dimensional motion to two–dimensional motion leads to a decrease in the system entropy. In addition, the isosteric heat of adsorption (Qst) was used to predict the isotherms of C3H6 and C3H8 at 298 and 303 K, respectively. When the predicted and experimental values are compared, the predicted isotherms are shown to be fully associated with the experimental values, with mean relative errors (MRE%) of less than 2%. Additionally, the C3H6 and C3H8 adsorption isotherms and selectivity for C3H6 adsorption were predicted using a combination of the DSS model and ideal adsorbed solution theory (IAST). The findings suggest that the overall adsorption capacity of the mixes rose as the mole fraction of C3H6 increased, but the adsorption capacity of the equimolar C3H6 and C3H8 in the three HP–Cu–BTC combinations was smaller than the pure component. Additionally, an undetectable shift in C3H6/C3H8 selectivity was seen when the molar percentage of C3H6 increased.

World Federation of Athletic Training and Therapy World Congress 2022 Peer-Reviewed Track Abstracts, May 5–7, 2022, Winnipeg, Manitoba, Canada

World Federation of Athletic Training and Therapy World Congress 2022 Peer-Reviewed Track Abstracts, May 5–7, 2022, Winnipeg, Manitoba, Canada

Verification of Reliability and Validity of Trunk Forward Tilt Angle Measurement During Gait Using 2-Dimensional Motion Analysis

ObjectiveThe purpose of this study was to verify the reliability and validity of trunk forward tilt angle measurement during gait using the 2-dimensional motion analysis, open-source software Kinovea. MethodsThe participants were 48 healthy people (23.3 ± 3.7 years of age), and the measurement task was normal gait. Two-dimensional motion analysis using Kinovea and measurement using a 3-dimensional motion analyzer were performed synchronously to calculate the forward tilt angle of the trunk during gait. The maximum and minimum values ​​of the trunk forward tilt angle in 1 gait cycle were used as representative values. The intraclass correlation coefficient and the minimum detectable change amount in Kinovea were calculated. We also verified the correlation with the measured values ​​using the 3-dimensional motion analyzer and the error by Bland-Altman analysis. ResultsThe intraclass correlation coefficient for Kinovea was 0.925 (95% confidence interval, 0.866-0.958) at the maximum and 0.918 (95% confidence interval, 0.854-0.954) at the minimum. The maximum value of the minimum detectable change amount was 2.7°, and the minimum value was 2.9°. The correlation coefficient between the methods was the maximum value r = 0.964 (R² = 0.929) and the minimum value r = 0.970 (R² = 0.941). The average difference between the methods (d) was –0.55 to –0.51° and the standard deviation of the difference between the measured values was 0.66 to 0.84°, and the minimum value was d = –0.59 to –0.54° and SDd = 0.63 to 0.91°. ConclusionThe reliability and validity of the measurement by 2-dimensional motion analysis of the trunk forward tilt angle in young adults were confirmed.

One dimensional Brownian motion with holding and jumping boundary

Let a particle start at some point in the unit interval and undergo Brownian motion in until it hits one of the end points. At this instant, the particle stays put for a finite holding time with an exponential distribution and then jumps back to a point inside with a probability density or parametrized by the boundary point it was at. The process starts afresh. The same evolution repeats independently each time. Many probabilistic aspects of this diffusion process are investigated in the paper by Peng and Li listed in the reference. The authors in the cited paper call this process diffusion with holding and jumping (DHJ). Our simple aim in this paper is to analyze the eigenvalues of a nonlocal boundary problem arising from this process. In particular, we answer a question on the spectral gap of the DHJ process raised at the end of the paper by Peng and Li.

Effects of Walking With a Cane on Frontal Plane Hip Joint Loading in Patients With Late-Stage Unilateral Hip Osteoarthritis

ObjectiveTo investigate the effects of walking with a cane on frontal plain bilateral hip joint loading in patients with late-stage unilateral hip osteoarthritis (OA). DesignNonrandomized experimental design. SettingUrban inpatient hospital. ParticipantsAdults (men, n=10; women, n=17) with osteoarthritis who were scheduled for total hip arthroplasty (N=27). InterventionGait with and without a T-cane was assessed using a 3-dimensional motion analysis system. Main Outcome MeasuresPeak hip adduction moment and hip adduction moment impulse, vertical ground reaction force, and ground reaction force impulse were assessed under 4 different conditions: OA side vs non-OA side with non-cane gait, OA side vs non-OA side with cane gait, non-cane vs cane gait on OA side, and non-cane vs cane gait on non-OA side. The lateral trunk lean angle in the stance phase on both sides was compared between with and without a cane. Pain during walking with and without a cane was also determined using a visual analog scale (0=no pain; 100=most painful). ResultsWalking with a cane reduced the peak hip adduction moment from an average of 0.76 to 0.57 Nm/kg (reduction approximately 25%) and the mean hip adduction moment impulse from 50.58 to 42.78 Nm/kg (reduction approximately 15%) on the affected side. Walking with a cane reduced the peak ground reaction force from an average of 10.15 to 9.20 N/kg but did not markedly affect the mean ground reaction force impulse on the affected side. The mean impulse of vertical ground force and hip adduction moment on the nonaffected side with a T-cane was larger than that without a cane (940.4 vs 899.2, 73.7 vs 68.8, respectively), albeit without statistical significance. The mean lateral trunk lean angle on the affected side was 5.85±3.95 degrees with a non-cane gait and 4.46±2.66 degrees with a T-cane gait, showing a significant difference. Furthermore, walking with a cane was associated with a significant decrease in the visual analog scale of pain from 42.1 to 26.4. ConclusionThese findings indicate that walking with a cane reduces the load and pain on the affected hip joint. The effect of the cane on the trunk lean was small, but it is worth noting that walking with a cane may increase the load on the healthy side.

Pendekatan Analisis Derau Putih untuk Arus Stokastik dari Gerak Brown Subfraksional

The subfractional Brownian motion is a Gaussian generalization of the Brownian motion whose increments are not stationary. In this paper we study the stochastic current of the one dimensional subfractional Brownian motion. For this purpose we use the method from white noise analysis by representing the subfractional Brownian motion as stochastic functionals of white noise. As the main result we prove that the stochastic current of the one dimensional subfractional Brownian motion is a generalized function in the space of Hida distributions.

First-passage Brownian functionals with stochastic resetting

We study the statistical properties of first-passage time functionals of a one dimensional Brownian motion in the presence of stochastic resetting. A first-passage functional is defined as where t f is the first-passage time of a reset Brownian process x(τ), i.e., the first time the process crosses zero. In here, the particle is reset to x R > 0 at a constant rate r starting from x 0 > 0 and we focus on the following functionals: (i) local time , (ii) residence time , and (iii) functionals of the form with n > −2. For first two functionals, we analytically derive the exact expressions for the moments and distributions. Interestingly, the residence time moments reach minima at some optimal resetting rates. A similar phenomena is also observed for the moments of the functional A n . Finally, we show that the distribution of A n for large A n decays exponentially as for all values of n and the corresponding decay length a n is also estimated. In particular, exact distribution for the first passage time under resetting (which corresponds to the n = 0 case) is derived and shown to be exponential at large time limit in accordance with the generic observation. This behavioural drift from the underlying process can be understood as a ramification due to the resetting mechanism which curtails the undesired long Brownian first passage trajectories and leads to an accelerated completion. We confirm our results to high precision by numerical simulations.

Evaluating Pelvis Rotation Style at Foot Contact: A Propensity Scored Biomechanical Analysis in High School and Professional Pitchers

Background: Early pelvis rotation has been associated with decreased throwing arm kinetics and conventionally was considered a component of proper pitching form in baseball throwers. However, previous assessments of pelvis rotation style have not accounted for confounders such as playing level, anthropometric characteristics, or ball velocity and have not evaluated sufficient sample sizes. Purpose: To compare kinetic and kinematic parameters based on pelvis rotation style in high school and professional pitchers. Study Design: Descriptive laboratory study. Methods: High school and professional baseball pitchers threw 8 to 12 fastball pitches while being evaluated using 3-dimensional motion capture (480 Hz). These pitchers were 1:1 propensity score matched by age, height, weight, handedness, and ball velocity based on early (<60°) versus late (≥60°) pelvis rotation style at foot contact. A total of 26 kinematic and 10 kinetic parameters were compared between groups. The kinematic parameters were used to conduct a linear regression between early and late pelvis rotation at foot contact. Results: Pelvis rotation at foot contact was not significantly associated with ball velocity for either high school (P = .243) or professional pitchers (P = .075). No difference was found in elbow varus torque between high school early rotators (57.5 ± 14.9 N·m) and late rotators (51.3 ± 14.7 N·m; P = .036) and between professional early rotators (80.1 ± 11.8 N·m) and late rotators (79.0 ± 11.2 N·m; P = .663). At foot contact in high school pitchers, stride length increased by 2.1% of body height (B = −0.205; β = −0.470; P < .001), trunk rotation increased by 4.2° (B = −0.417; β = −0.488; P < .001), and trunk flexion at foot contact decreased by 4.4° (B = 0.442; β = 0.476; P < .001) with every 10° increase in pelvis rotation. At foot contact in professional pitchers, stride length increased by 2.3% of body height (B = –0.229; β = –0.478; P < .001), trunk rotation increased by 4.3° (B = –0.431; β = –0.515; P < .001), and trunk flexion decreased by 4.0° (B = 0.404; β = 0.373; P < .001) with every 10° increase in pelvis rotation. Conclusion: Pelvis rotation at foot contact was associated with several kinematic parameters in both groups and may influence mechanics further along the kinetic chain. Landing open or closed was not significantly associated with throwing arm kinetics or ball velocity for both high school and professional baseball pitchers, contrary to previous thought. Clinical Relevance: Coaches and players may better focus their efforts on refining other kinematic parameters for enhanced performance outcomes and safe pitching mechanics.

Efficient deformation mechanisms enable invasive cancer cells to migrate faster in 3D collagen networks

Cancer cell migration is a widely studied topic but has been very often limited to two dimensional motion on various substrates. Indeed, less is known about cancer cell migration in 3D fibrous-extracellular matrix (ECM) including variations of the microenvironment. Here we used 3D time lapse imaging on a confocal microscope and a phase correlation method to follow fiber deformations, as well as cell morphology and live actin distribution during the migration of cancer cells. Different collagen concentrations together with three bladder cancer cell lines were used to investigate the role of the metastatic potential on 3D cell migration characteristics. We found that grade-3 cells (T24 and J82) are characterized by a great diversity of shapes in comparison with grade-2 cells (RT112). Moreover, grade-3 cells with the highest metastatic potential (J82) showed the highest values of migration speeds and diffusivities at low collagen concentration and the greatest sensitivity to collagen concentration. Our results also suggested that the small shape fluctuations of J82 cells are the signature of larger migration velocities. Moreover, the displacement fields generated by J82 cells showed significantly higher fiber displacements as compared to T24 and RT112 cells, regardless of collagen concentration. The analysis of cell movements enhanced the fact that bladder cancer cells were able to exhibit different phenotypes (mesenchymal, amoeboid). Furthermore, the analysis of spatio-temporal migration mechanisms showed that cancer cells are able to push or pull on collagen fibers, therefore producing efficient local collagen deformations in the vicinity of cells. Our results also revealed that dense actin regions are correlated with the largest displacement fields, and this correlation is enhanced for the most invasive J82 cancer cells. Therefore this work opens up new routes to understand cancer cell migration in soft biological networks.

Evaluating 3D Human Motion Capture on Mobile Devices

Computer-vision-based frameworks enable markerless human motion capture on consumer-grade devices in real-time. They open up new possibilities for application, such as in the health and medical sector. So far, research on mobile solutions has been focused on 2-dimensional motion capture frameworks. 2D motion analysis is limited by the viewing angle of the positioned camera. New frameworks enable 3-dimensional human motion capture and can be supported through additional smartphone sensors such as LiDAR. 3D motion capture promises to overcome the limitations of 2D frameworks by considering all three movement planes independent of the camera angle. In this study, we performed a laboratory experiment with ten subjects, comparing the joint angles in eight different body-weight exercises tracked by Apple ARKit, a mobile 3D motion capture framework, against a gold-standard system for motion capture: the Vicon system. The 3D motion capture framework exposed a weighted Mean Absolute Error of 18.80° ± 12.12° (ranging from 3.75° ± 0.99° to 47.06° ± 5.11° per tracked joint angle and exercise) and a Mean Spearman Rank Correlation Coefficient of 0.76 for the whole data set. The data set shows a high variance of those two metrics between the observed angles and performed exercises. The observed accuracy is influenced by the visibility of the joints and the observed motion. While the 3D motion capture framework is a promising technology that could enable several use cases in the entertainment, health, and medical area, its limitations should be considered for each potential application area.