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Context: Anterior cruciate ligament injuries are directly related to the control of dynamic knee valgus in the landing of a jump, and this is mainly due to the correct activation and neuromuscular function of the lower-extremity muscles. The aim of the study is to assess the relationship between lower limb muscle activity during a single-legged drop jump and knee frontal plane projection angle (FPPA). Design: A correlation study. Methods: Thirty healthy collegiate female athletes were included in the study. Main outcomes measures were peak knee FPPA and muscle activity (% of maximal voluntary isometric contraction). Peak knee FPPA during a single-legged drop jump test was identified using a 2-dimensional motion analysis system. Muscle activity was assessed using a surface electromyograph for gluteus maximus, gluteus medius, biceps femoris, semitendinosus, vastus medialis quadriceps, vastus lateralis quadriceps, medial gastrocnemius, and lateral gastrocnemius. All variables were assessed for both dominant and nondominant limbs. A correlation analysis between peak knee FPPA and muscle activity was performed. Statistical significance was set at P <.05. Results: A mean peak knee FPPA of 14.52° and 13.38° was identified for dominant and nondominant limb single-legged drop jump test, respectively. Muscle activity (% of maximal voluntary isometric contraction) for muscles assessed ranged from 43.97% to 195.71% during the single-legged drop jump test. The correlation analysis found no significant correlation between any of the muscles assessed and peak knee FPPA during the single-legged drop jump test (Pearson coefficient between −.3 and.1). Conclusions: There is no association between muscle activity from the lower limb muscles and the knee FPPA during a single-legged drop jump in female athletes. Thus, different muscle properties should be assessed in order to understand such an important movement as the knee FPPA during a jump. [ABSTRACT FROM AUTHOR]

The present randomized study investigated the effect of acute supplementation of 800 mg/kg of ketone monoester ingestion (KE) or placebo (PL) and 210 mg/kg of NaHCO3 co-ingestion on cycling performance of WorldTour cyclists during a road cycling stage simulation. Twenty-eight cyclists participated in the study (27.46 ± 4.32 years; 1.80 ± 0.06 m; 69.74 ± 6.36 kg). Performance, physiological, biochemical, and metabolism outcomes, gut discomfort, and effort perceived were assessed during a road cycling simulation composed of an 8-min time-trial (TT) performance + 30-s TT + 4.5 hr of outdoor cycling + a second 8-min TT + a second 30-s TT. Greater absolute and relative mean power during the first 8-min TT (F = 5.067, p =.033, η p 2 =.163 , F = 5.339, p =.029, η p 2 =.170 , respectively) was observed after KE than after PL (KE: 389 ± 34, PL: 378 ± 44 W, p =.002, d = 0.294 and KE: 5.60 ± 0.42, PL: 5.41 ± 0.44 W/kg, p =.001, d = 0.442). Additionally, greater concentration of β-hydroxybutyrate blood concentration (F = 42.195, p <.001, η p 2 =.619) was observed after KE than after PL during the first steps of the stage (e.g., after warm-up KE: 1.223 ± 0.642, PL: 0.044 ± 0.058 mM, p <.001, d = 2.589), although the concentrations returned to near baseline after 4.5 hr of outdoor cycling. Moreover, higher values of anion gap were observed (F = 2.333, p =.026, η p 2 =.080) after KE than after PL ingestion, after the warm-up and after the first 8-min and 30-s TT. Additionally, lower concentrations of HCO 3 − were reported in the KE condition after warm-up and after the first 8-min and 30-s TT. During the initial phase of the stage simulation, acute supplementation with KE + NaHCO3 co-ingestion enhanced 8-min TT cycling performance (3.1%) in WorldTour cyclists with a concomitant hyperketonaemia. [ABSTRACT FROM AUTHOR]

Context: Single- and dual-task walking gait assessments have been used to identify persistent movement and cognitive dysfunction among athletes with concussions. However, it is unclear whether previous ankle sprain injuries confound these outcomes during baseline testing. The purpose of this study was to determine the effects of (1) ankle sprain history and (2) time since prior ankle sprain injury on single- and dual-task spatiotemporal gait outcomes and cognitive measures. Design: Cross- sectional study. Methods: We assessed 60 college Division-I athletes (31 with ankle sprain history; 13 females and 18 males, 19.3 [0.8] y; 29 with no ankle sprain history, 14 females and 15 males, 19.7 [0.9] y) who completed injury history forms and underwent concussion baseline testing. Athletes completed single- and dual-task gait assessments by walking back and forth along an 8-m walkway for 40 seconds. Athletes wore a smartphone with an associated mobile application on their lumbar spine to record spatiotemporal gait parameters and dual-task cognitive performance. Separate multivariate analyses of variance were used to assess the effects of ankle sprain injury history on spatiotemporal measures, gait variability, and cognitive performance. We performed a multivariate regression subanalysis on athletes who reported time since injury (n = 23) to assess temporal effects on gait and cognitive performance. Results: Athletes with and without a histoiy of ankle sprains had comparable spatiotemporal and gait variability outcomes during single- (P = .42; P = .13) and dual-task (P = .75; P = .55) conditions. Additionally, ankle sprain injury history did not significantly influence cognitive performance (P = .35). Finally, time since ankle sprain did not significantly affect single- (P = .75) and dual-task gait (P = .69), nor cognitive performance (P = 19). Conclusions: Ankle sprain injury history did not significantly alter spatiotemporal gait outcomes nor cognitive performance during this common clinical assessment. Future studies may consider including athletes with ankle sprain injury history during concussion assessments. [ABSTRACT FROM AUTHOR]

Context: To assess the reliability of a remote 2D markerless motion tracking method (Kinovea) to quantify knee and hip angles during dynamic tasks. Methods: Fourteen healthy adults performed body weight squats and lateral lunges while video recording themselves at home. Knee and hip angles were quantified in the sagittal plane for the squats and in the frontal plane for the lateral lunges. Two students each performed the video analysis procedure twice, 2 weeks apart. Intraclass correlation coefficients were used to calculate the intrarater and interrater reliability for angles at maximum depth. The intrarater and interrater agreement over the joint angle-time signals were quantified using a validation metric; an acceptable agreement threshold was set at a validation metric of 0.803 or higher. Standard error of measurement (SEM) was also calculated. Results: Reliability was good to excellent (intraclass correlation coefficients = .80-.98) for all angle comparisons at maximum depth. The agreement over the entire joint angle-time signal was acceptable for all squat variables except for the interrater hip angle comparison (validation metric = 0.797). None of the lateral lunge variables met the threshold of acceptable agreement. The mean SEM across participants for all joint angle-time signal and for maximum depth was acceptable (<5°) for all measurements (SEM = 1.2°-4.9°). Conclusions: Overall, the reliability, agreement, and SEM quantified in this study support the integration of remote methods to quantify lower-extremity kinematics into research and clinical practice. [ABSTRACT FROM AUTHOR]

Context: Early identification of incoming military personnel at elevated odds for bone stress injury (BSI) is important for the health and readiness of the US military. Design: Prospective cohort study. Methods: Knee kinematic data of the incoming US Military Academy cadets were collected while performing a jump-landing task (The Landing Error Scoring System) using a markerless motion capture system and depth camera. Data on incidence of lower-extremity injury, including BSI, were collected throughout the study period. Results: A total of 1905 participants (452 females, 23.7%) were examined for knee valgus and BSI status. A total of 50 BSI occurred during the study period (incidence proportion = 2.6%). The unadjusted odds ratio for BSI at initial contact was 1.03 (95% confidence interval [CI], 0.94–1.14; P =.49). Adjusted for sex, the odds ratio for BSI at initial contact was 0.97 (95% CI, 0.87–1.06; P =.47). At the instant of maximum knee-flexion angle, the unadjusted odds ratio was 1.06 (95% CI, 1.02–1.10; P =.01), and the odds ratio was 1.02 (95% CI, 0.98–1.07; P =.29) after adjusting for sex. This suggests that there was not a significant enough association for an increase in the odds of BSI based on either degree of knee valgus. Conclusions: Our results did not demonstrate an association between knee valgus angle data during a jump-landing task and future increased odds of BSI in a military training population. Further analysis is warranted, but the results suggests the association between kinematics and BSI cannot be effectively screened by knee valgus angle data in isolation. [ABSTRACT FROM AUTHOR]

Context: Different resistance exercise determinants modulate the musculotendinous adaptations following eccentric hamstring training. The Nordic Hamstring Exercise (NHE) can be performed 2-fold: the movement velocity irreversibly increases toward the end of the range of motion or it is kept constant. Design: This cross-sectional study aimed to investigate if the downward acceleration angle (DWAangle) can be used as a classification parameter to distinguish between increasing and constant velocity NHE execution. Furthermore, the kinetic and kinematic differences of these 2 NHE execution conditions were examined by analyzing the DWAangle in relation to the angle of peak moment. Methods: A total of 613 unassisted NHE repetitions of 12 trained male sprinters (22 y, 181 cm, 76 kg) were analyzed. Results: The majority of analyzed parameters demonstrated large effects. NHEs with constant velocity (n = 285) revealed significantly higher impulses (P <.001; d = 2.34; + 61%) and fractional time under tension (P <.001; d = 1.29; +143%). Although the generated peak moments were significantly higher for constant velocity (P =.003; d = 0.29; +4%), they emerged at similar knee flexion angles (P =.167; d = 0.28) and revealed on average just low relationships to the DWAangle ( R mean 2 = 22.4 %). DWAangle highly correlated with the impulse ( R mean 2 = 60.8 %) and δ (DWAangle–angle of peak moment; R mean 2 = 83.6 %). Conclusions: Relating DWAangle to angle of peak moment assists to distinguish between significantly different NHE execution, which will potentially elicit different musculotendinous adaptations. These insights are essential for coaches and athletes to understand how to manipulate eccentric hamstring training to change its purpose. [ABSTRACT FROM AUTHOR]

A non-slip constraint between a particle and a wall is applied at the microscopic level of collision dynamics using the rough sphere model. We analyze the consequences of the translation–rotation coupling of a rough sphere confined between two parallel planar walls and establish that shearing the walls past each other (i) preferentially deposits energy into the rotational degree of freedom and (ii) results in a bounded oscillation of the energy of the confined particle. [ABSTRACT FROM AUTHOR]

Objectives: Although nonsurgical and surgical management of knee arthrofibrosis has been reported in the literature, there is little information on the effect of procedural treatment modalities of refractory arthrofibrosis on clinical outcomes. The purpose of this case report is to describe the intervention of refractory knee arthrofibrosis after anterior cruciate ligament reconstruction and investigate long-term clinical outcomes after procedural intervention. Methods: A 27-year-old male presented with decreased range of motion (ROM), patellar mobility, strength, and knee joint function following anterior cruciate ligament reconstruction of his left knee. After failed conservative management, the patient underwent manipulation under anesthesia (MUA) to release scar tissue. Following MUA, the emphasis of comprehensive physiotherapy was on decreasing inflammation, relieving pain, and maintaining patellar mobility while increasing knee joint ROM and strength. Knee ROM, patellofemoral motion, gait, and quadriceps recruitment were measured 3, 6, 12, and 24 months after MUA. Results: At 2-year follow-up after MUA, the patient continued to present with decreased ROM and quadriceps strength compared to the contralateral knee, but had returned to a running program and reported knee joint dysfunction no longer interfered with his daily activities. Conclusions: This case report demonstrates signs and symptoms that could indicate knee arthrofibrosis and introduces procedural intervention for refractory arthrofibrosis after anterior cruciate ligament reconstruction. [ABSTRACT FROM AUTHOR]

Context: Laboratorial 3-dimensional kinematic analyses have shown changes in the single-leg squat's (SLS) pattern of patients with femoroacetabular impingement syndrome (FAIS). However, it is unknown whether clinicians are able to detect these changes using 2-dimensional kinematics. Objective: To compare the frontal plane 2-dimensional kinematics of patients with FAIS and asymptomatic individuals in the SLS test performed in a clinical setting. Design: Case-control study. Setting: Physical therapy clinic. Participants: Twenty men with bilateral FAIS and 20 asymptomatic men. Main Outcome Measures: Two-dimensional kinematic analysis was collected in the frontal plane during the execution of the SLS test. The outcomes were squat depth, pelvic drop (pelvis angle relative to the horizontal plane), hip adduction (femur angle relative to the pelvis), and knee valgus (femur angle relative to the tibia). Results: Most and least painful limbs of patients with FAIS had squat depth (9.8% [2.9%] and 9.5% [3.1%] of height), pelvic drop (4.2° [3.9°] and 3.7° [4.2°]), hip adduction (74.9° [5.8°] and 75.9° [5.7°]), and knee valgus (4.0° [11.0°] and 5.0° [9.9°]) similar to asymptomatic individuals (9.0% [2.3%], 4.8° [2.6°], 73.7° [4.9°], and −1.7° [8.5°]; P >.05 for all). Conclusion: The frontal plane 2-dimensional kinematic analysis of the SLS test in the clinical setting is not able to distinguish patients with FAIS from asymptomatic individuals. [ABSTRACT FROM AUTHOR]

Context: Excessive hip adduction and internal rotation are abnormal movements that may lead to the onset and progression of patellofemoral pain. Previous studies have reported that lower dynamic frontal plane hip joint stiffness in the gait of women is associated with the magnitude of hip adduction and internal rotation angles. However, the factors contributing to the lack of dynamic frontal plane hip joint stiffness in the gait of young women are unclear. This study aims to investigate the factors affecting dynamic frontal plane hip joint stiffness during the weight-acceptance phase of the gait of healthy young women. Design: Cross-sectional study. Methods: This study included 30 healthy women between the ages of 18 and 30 years. The pelvic width/femur length ratio was calculated by dividing the pelvic width by the femur length. Data on hip kinematics and kinetics and activation of the gluteus maximus and medius, tensor fasciae latae, and adductor longus muscles during gait were collected using a motion capture system, force plates, and surface electromyography. Stepwise multiple regression analysis was conducted to determine the extent to which each independent factor affected dynamic frontal plane hip joint stiffness. Results: In healthy young women, decreased dynamic frontal plane hip joint stiffness was associated with decreased muscle activity of the gluteus maximus during the gait, as well as greater pelvic width/femur length ratio. Conclusions: Women with a relatively great pelvic width relative to femur length may have more difficulty in producing dynamic frontal plane hip joint stiffness. However, increasing the muscle activity of the gluteus maximus may contribute to increased dynamic frontal plane hip joint stiffness. [ABSTRACT FROM AUTHOR]

Context: Aberrant movement patterns among individuals with concussion history have been reported during sport-related movement. However, the acute postconcussion kinematic and kinetic biomechanical movement patterns during a rapid acceleration–deceleration task have not been profiled and leaves their progressive trajectory unknown. Our study aimed to examine single-leg hop stabilization kinematics and kinetics between concussed and healthy-matched controls acutely (≤7 d) and when asymptomatic (≤72 h of symptom resolution). Design: Prospective, cohort laboratory study. Methods: Ten concussed (60% male; 19.2 [0.9] y; 178.7 [14.0] cm; 71.3 [18.0] kg) and 10 matched controls (60% male; 19.5 [1.2] y; 176.1 [12.6] cm; 71.0 [17.0] kg) completed the single-leg hop stabilization task under single and dual task (subtracting by 6's or 7's) at both time points. Participants stood on a 30-cm tall box set 50% of their height behind force plates while in an athletic stance. A synchronized light was illuminated randomly, queuing participants to initiate the movement as rapidly as possible. Participants then jumped forward, landed on their nondominant leg, and were instructed to reach and maintain stabilization as fast as possible upon ground contact. We used 2 (group) × 2 (time) mixed-model analyses of variance to compare single-leg hop stabilization outcomes separately during single and dual task. Results: We observed a significant main group effect for single-task ankle plantarflexion moment, with greater normalized torque (mean difference = 0.03 N·m/body weight; P =.048, g = 1.18) for concussed individuals across time points. A significant interaction effect for single-task reaction time indicated that concussed individuals had slower performance acutely relative to asymptomatic (mean difference = 0.09 s; P =.015, g = 0.64), while control group performance was stable. No other main or interaction effects for single-leg hop stabilization task metrics were present during single and dual task (P ≥.051). Conclusions: Greater ankle plantarflexion torque coupled with slower reaction time may indicate stiff, conservative single-leg hop stabilization performance acutely following concussion. Our findings shed preliminary light on the recovery trajectories of biomechanical alterations following concussion and provide specific kinematic and kinetic focal points for future research. [ABSTRACT FROM AUTHOR]

Context: Ball velocity for baseball pitchers is influenced by a multitude of factors along the kinetic chain. While a vast amount of data currently exist exploring lower-extremity kinematic and strength factors in baseball pitchers, no previous study has systematically reviewed the available literature. Objective: The aim of this systematic review was to perform a comprehensive assessment of the available literature investigating the association between lower-extremity kinematic and strength parameters and pitch velocity in adult pitchers. Evidence acquisition: Cross-sectional studies that investigated the association between lower-body kinematic and strength factors and ball velocity in adult pitchers were selected. A methodological index for nonrandomized studies checklist was used to evaluate the quality of all included studies. Evidence synthesis: Seventeen studies met the inclusion criteria comprising a total of 909 pitchers (65%, professional, 33% college, and 3% recreational). The most studied elements were hip strength and stride length. The mean methodological index for nonrandomized studies score was 11.75 of 16 (range = 10-14). Pitch velocity was found to be influenced by several lower-body kinematic and strength factors including the following: (1) hip range of motion and strength of muscles around the hip and pelvis, (2) alterations in stride length, (3) alterations in lead knee flexion/extension, and (4) several pelvic and trunk spatial relationships throughout the throwing phase. Conclusions: Based on this review, we conclude that hip strength is a well-established predictor of increased pitch velocity in adult pitchers. Further studies in adult pitchers are needed to elucidate the effect of stride length on pitch velocity given mixed results across multiple studies. This study can provide a basis for trainers and coaches to consider the importance of lower-extremity muscle strengthening as a means by which adult pitchers can improve pitching performance. [ABSTRACT FROM AUTHOR]

Blue compact galaxies, also known as H  ii galaxies, are dwarf, star-forming objects with relatively simple dynamics, which allows for the investigation of star formation mechanisms in a cleaner manner compared to late-type objects. In this study, we have examined various characteristics of the interstellar medium, in connection with the kinematics and dynamics of ionized gas, in Tol 1004-296 and Tol 0957-278. These two objects were observed using the SOAR Integral Field Spectrometer (SIFS) attached to the Southern Observatory for Astrophysical Research (SOAR). Both galaxies were observed with two gratings: one with medium resolution for monochromatic and abundance maps, and another with high resolution for kinematics and profile analysis. Additionally, we conducted an analysis on the velocity and velocity dispersion maps using intensity–velocity dispersion (I-σ) and velocity–velocity dispersion (Vr-σ) diagrams. Neither object exhibits a rotation pattern, and only Tol 1004-296 shows a velocity gradient between the two principal knots. However, the study reveals the significant role played by velocity dispersion in the star formation process. Specifically, we identified a relationship between monochromatic intensity, metallicity, and velocity dispersion, where high emission corresponds to low metallicity and low velocity dispersion. Tol 1004-296, in particular, exhibits a distinctive linear high velocity dispersion pattern between the two main knots, suggesting that both star formation sites are pushing the gas in opposite directions. [ABSTRACT FROM AUTHOR]

OBJECTIVE: There is no consensus on which sit-up strategy to adopt in knee osteoarthritis patients of different ages. Therefore, this study evaluated the biomechanical characteristics of sit-ups in knee osteoarthritis patients of different ages compared with healthy individuals by meta-analysis system and analyzed the sit-up movement patterns of patients of different ages to provide a reference for improving the sit-up function of patients. METHODS: By March 2023, observational studies of biomechanical characteristics of sitting up in patients with knee osteoarthritis and healthy population were retrieved on PubMed, Web of Science and CNKI. Subjects were required to be patients over 50 years of age with knee osteoarthritis who had KellgrenLawrence severity grading ≥I on knee imaging and who had regular knee pain. Subjects were analyzed by age (50-60 years vs. over 60 years) and severity (mild to moderate patients vs. severe patients) subgroups according to inclusion and exclusion criteria. Quality assessment was performed using the modified Down and black scale. Stata 16.0 software was used to perform subgroup analysis to determine the biomechanical characteristics of sitting up in patients with knee osteoarthritis of different ages and severities. RESULTS: A total of 14 randomized controlled trials (824 subjects) were included in the meta-analysis. The mean quality score of all included literature was 76.2, with a range of 66.7 to 86.7, all of which were of medium to high quality and representative. The included studies were of moderate to high quality and representative. Meta-analysis results found that (1) compared to healthy individuals, patients with knee osteoarthritis had longer total sitting up time (SMD=0.92, 95%CI:0.76-1.09), P < 0.001) and longer extension phase time (SMD=0.46, 95%CI:0.18-0.74, P=0.001). Compared to mild to moderate patients, the total duration increased more significantly in severe patients (P < 0.001) and the duration of the extension phase increased more significantly in patients over 60 years of age than in patients 50-60 years of age (P=0.001). (2) Compared to healthy individuals, patients with knee osteoarthritis had greater sitting-up trunk flexion motion range (SMD=0.64, 95%CI:0.37-0.91, P < 0.001); knee flexion motion range (SMD=-0.47, 95%CI: -0.70 to -0.24, P < 0.001) and ankle dorsiflexion motion range (SMD=-0.32, 95%CI:-0.56 to -0.08, P=0.01) were smaller. And knee flexion motion range decreased more significantly in patients over 60 years of age than in patients 50-60 years of age (P < 0.001). (3) The peak hip flexion moment (SMD=-0.57, 95%CI:-0.83 to -0.31, P < 0.001) and peak knee extension moment (SMD=-0.83, 95%CI:-1.08 to -0.59, P < 0.001) were smaller in patients with knee osteoarthritis. CONCLUSION: (1) Patients with knee osteoarthritis over the age of 60 years have a longer sit-up cushion and extension phase than patients aged 50 to 60 years. The increase in total sit-up duration was also more pronounced in patients with higher severity grades. The increased length of sitting up in patients with advanced age and knee osteoarthritis severity may increase the duration of cartilage loading, exacerbate knee pain symptoms, and increase the difficulty of sitting up in this population. (2) Patients with knee osteoarthritis exhibit limited knee and ankle flexion motion range. Knee mobility is more limited in patients over 60 years of age. (3) Patients with knee osteoarthritis have reduced peak hip flexion and knee extension moments, which may be a compensatory strategy for pain relief. [ABSTRACT FROM AUTHOR]

We present a new method for selecting A-type supergiants (A-SGs hereafter) in the LAMOST DR5 data set using the line indices, and identify 40 spectra of 30 A-SG candidates. Based on the analysis of the absolute magnitude of Gaia DR3, SIMBAD data base, ZTF light variation data, and spectral characteristics of A-SGs, we classified the 30 A-SG candidates into 18 A-SGs and 12 A-SG candidates with different levels of credibility. We also subclassify spectral types of 18 A-SGs and 12 A-SG candidates by using human eyes and find a good consistency between our results and those of MKCLASS for most of them. The spatial distribution of 18 A-SGs and 12 A-SG candidates indicates that they are located in the Galactic latitude smaller than 20○. In addition, the distribution of 13 A-SGs and 7 A-SG candidates with reliable Gaia DR3 kinematic parameters in the Toomre diagram indicates that they are located in the Galactic disc, which also suggests that they are young, massive stars. Our selection has worked out well, in that only one A-SG candidate and one A-SG appear to exhibit discrepant kinematics. [ABSTRACT FROM AUTHOR]

As cool clouds are entrained by a hot supersonic galactic wind, they may be shredded by hydrodynamical instabilities and incorporated into the hot flow. One-dimensional steady-state calculations show how cool cloud entrainment affects the bulk thermodynamics and kinematics of the hot gas: mass-loading decelerates the hot flow and changes its entropy. Here, we investigate the stability of mass-loaded hot winds using both perturbation analysis and 3D time-dependent radiative hydrodynamical simulations. We show that mass-loading is stable over a broad range of parameters and that the 1D time-steady analytic solutions exactly reproduce the 3D time-dependent calculations, provided that the flow does not decelerate sufficiently to become subsonic. For higher values of the mass-loading, the flow develops a second sonic point, with the first being at the edge of the wind-driving region. Strong deceleration increases the wind density and the flow becomes radiative, undergoing a thermal instability to form elongated dense cometary filaments. We explore the mass-loading parameters required to trigger this behaviour. For certain approximations, we can derive analytic criteria. In general, a mass-loading rate similar to the initial hot-mass outflow rate is required. In this sense, the destruction of small cool clouds by a hot flow may ultimately spontaneously generate fast cool filaments, as observed in starburst winds. Lastly, we find that the kinematics of filaments is sensitive to the slope of the mass-loading function. Filaments move faster than the surrounding wind if mass-loading is over long distances whereas filaments move slower than their surroundings if mass-loading is abrupt. [ABSTRACT FROM AUTHOR]

We present spatially resolved kinematics of 27 ALMA-identified dust-obscured star-forming galaxies (DSFGs) at z  ∼ 1.3–2.6, as traced by Hα emission using VLT/KMOS near-infrared integral field spectroscopy from the 'KMOS-ALMA Observations of Submillimetre Sources' (KAOSS) Large Programme. We derive Hα rotation curves and velocity dispersion profiles for the DSFGs, and find that among the 27 sources with bright, spatially extended Hα emission, 24 display evidence for disc-like kinematics. We measure a median inclination-corrected velocity at 2.2  R d of v rot = 190 ± 40 km s−1 and intrinsic velocity dispersion of σ0 = 87 ± 6 km s−1 for these disc-like sources. The kinematics yield median circular velocities of v circ = 230 ± 20 km s−1 and dynamical masses within 2 R e (∼ 7 kpc radius) of M dyn = (1.1 ± 0.2) × 1011 M⊙. Compared to less actively star-forming galaxies, KAOSS DSFGs are both faster rotating with higher intrinsic velocity dispersions, but have similar v rot/σ0 ratios, median v /σ0 = 2.5 ± 0.5. We suggest that the kinematics of the DSFGs are primarily rotation supported but with a non-negligible contribution from pressure support, which may be driven by star formation or mergers/interactions. We estimate the normalization of the stellar mass Tully–Fisher relation (sTFR) for the disc-like DSFGs and compare it with local studies, finding no evolution at fixed slope between z  ∼ 2 and z  ∼ 0. Finally, we show that the kinematic properties of the DSFG population are consistent with them evolving into massive early-type galaxies, the dominant z  ∼ 0 population at these masses. [ABSTRACT FROM AUTHOR]

AbstractThe meniscus plays a crucial role in the proper functioning of the knee joint, and when it becomes damaged, partial removal or replacement is necessary to restore proper function. Understanding the stress and deformation of the meniscus during various movements is essential for developing effective materials for meniscus repair. However, accurately estimating the contact mechanics of the knee joint can be challenging due to its complex shape and the dynamic changes it undergoes during movement. To address this issue, the open-source software SCONE can be used to establish a kinematics model that monitors the different states of the knee joint during human motion and obtains relevant gait kinematics data. To evaluate the stress and deformation of the meniscus during normal human movement, values of different states in the movement gait can be selected for finite element analysis (FEA) of the knee joint. This analysis enables researchers to assess changes in the meniscus. To evaluate meniscus damage, it is necessary to obtain changes in its mechanical behavior during abnormal movements. This information can serve as a reference for designing and optimizing the mechanical performance of materials used in meniscus repair and replacement. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive comparison between a marker-based motion capture system (MMC) and a video-based motion capture system (VMC) in the context of kinematic analysis using musculoskeletal models. Focusing on joint angles, the study aimed to evaluate the accuracy of VMC as a viable alternative for biomechanical research. Eighteen healthy subjects performed isolated movements with 17 joint degrees of freedom, and their kinematic data were collected using both an MMC and a VMC setup. The kinematic data were entered into the AnyBody Modelling System, which enables the calculation of joint angles. The mean absolute error (MAE) was calculated to quantify the deviations between the two systems. The results showed good agreement between VMC and MMC at several joint angles. In particular, the shoulder, hip and knee joints showed small deviations in kinematics with MAE values of 4.8∘, 6.8∘ and 3.5∘, respectively. However, the study revealed problems in tracking hand and elbow movements, resulting in higher MAE values of 13.7∘ and 27.7∘. Deviations were also higher for head and thoracic movements. Overall, VMC showed promising results for lower body and shoulder kinematics. However, the tracking of the wrist and pelvis still needs to be refined. The research results provide a basis for further investigations that promote the fusion of VMC and musculoskeletal models. [ABSTRACT FROM AUTHOR]

AbstractThis study investigated whether modes of variance in trial-to-trial whole-body kinematic variability identified by principal component analysis (PCA) were consistent across data pre-processing conditions generated from a common dataset. Comparisons made included 1) when trajectory data was expressed in a global vs. local reference frame; 2) when the number of landmarks used to represent whole-body motion differed, and; 3) whether input trajectory data were normalized to participant stature. Varying data pre-processing conditions prior to PCA does not bias the total variance identified. However, it can influence how modes of variance are dispersed across PCs, which in turn, can influence interpretation. [ABSTRACT FROM AUTHOR]

Change of direction, stops, and pivots are among the most common non-contact movements associated with anterior cruciate ligament (ACL) injuries in soccer. By observing these dynamic movements, clinicians recognize abnormal kinematic patterns that contribute to ACL tears such as increased knee valgus or reduced knee flexion. Different motions and physical demands are observed across playing positions, which may result in varied lower limb kinematic patterns. In the present study, 28 college and sub-elite soccer players performed four dynamic motions (change of direction with and without ball, header, and instep kick) with the goal of examining the effect of on-field positioning, leg dominance, and gender in lower body kinematics. Motion capture software monitored joint angles in the knee, hip, and ankle. A three-way ANOVA showed significant differences in each category. Remarkably, centrally positioned players displayed significantly greater knee adduction (5° difference, p = 0.013), hip flexion (9° difference, p = 0.034), hip adduction (7° difference, p = 0.016), and dorsiflexion (12° difference, p = 0.022) when performing the instep kick in comparison to their laterally positioned counterparts. These findings suggest that central players tend to exhibit a greater range of motion when performing an instep kicking task compared to laterally positioned players. At a competitive level, this discrepancy could potentially lead to differences in lower limb muscle development among on-field positions. Accordingly, it is suggested to implement position-specific prevention programs to address these asymmetries in lower limb kinematics, which can help mitigate dangerous kinematic patterns and consequently reduce the risk of ACL injury in soccer players. [ABSTRACT FROM AUTHOR]

Background: Rotator cuff disorders, whether symptomatic or asymptomatic, may result in abnormal shoulder kinematics (scapular rotation and glenohumeral translation). This study aimed to investigate the effect of rotator cuff tears on in vivo shoulder kinematics during a 30° loaded abduction test using single-plane fluoroscopy. Materials and methods: In total, 25 younger controls, 25 older controls and 25 patients with unilateral symptomatic rotator cuff tears participated in this study. Both shoulders of each participant were analysed and grouped on the basis of magnetic resonance imaging into healthy, rotator cuff tendinopathy, asymptomatic and symptomatic rotator cuff tears. All participants performed a bilateral 30° arm abduction and adduction movement in the scapular plane with handheld weights (0, 2 and 4 kg) during fluoroscopy acquisition. The range of upward–downward scapular rotation and superior–inferior glenohumeral translation were measured and analysed during abduction and adduction using a linear mixed model (loads, shoulder types) with random effects (shoulder ID). Results: Scapular rotation was greater in shoulders with rotator cuff tendinopathy and asymptomatic rotator cuff tears than in healthy shoulders. Additional load increased upward during abduction and downward during adduction scapular rotation (P < 0.001 in all groups but rotator cuff tendinopathy). In healthy shoulders, upward scapular rotation during 30° abduction increased from 2.3° with 0-kg load to 4.1° with 4-kg load and on shoulders with symptomatic rotator cuff tears from 3.6° with 0-kg load to 6.5° with 4-kg load. Glenohumeral translation was influenced by the handheld weights only in shoulders with rotator cuff tendinopathy (P ≤ 0.020). Overall, superior glenohumeral translation during 30° abduction was approximately 1.0 mm with all loads. Conclusions: The results of glenohumeral translation comparable to control but greater scapular rotations during 30° abduction in the scapular plane in rotator cuff tears indicate that the scapula compensates for rotator cuff deficiency by rotating. Further analysis of load-dependent joint stability is needed to better understand glenohumeral and scapula motion. Level of evidence: Level 2. Trial registration: Ethical approval was obtained from the regional ethics committee (Ethics Committee Northwest Switzerland EKNZ 2021-00182), and the study was registered at clinicaltrials.gov on 29 March 2021 (trial registration number NCT04819724, https://clinicaltrials.gov/ct2/show/NCT04819724). [ABSTRACT FROM AUTHOR]

This paper develops a theoretical basis and a systematic process for resolving all inertia forces along generalized coordinates from the overall energy equation of a dynamical system. The theory is developed for natural systems with scleronomic constraints, where the potential energy is independent of generalized velocities. The process involves expansion of the energy equation, and specifically a special expansion of the kinetic energy term, from which the inertia forces emerge. The expansion uses fundamental kinematic identities of the phase space. It is also guided by insights drawn from the structure of the Hamiltonian function. The resulting equation has the structure of the D'Alembert's equation but involving generalized coordinates, from which the Lagrange's equations of motion are obtained. The expansion process elucidates how certain inertia forces manifest in the energy equation as composite terms that must be accurately resolved along different generalized coordinates. The process uses only the system energy equation, and neither the Hamiltonian nor the Lagrangian function are required. Extension of this theory to non-autonomous and non-holonomic systems is an area of future research. [ABSTRACT FROM AUTHOR]

Premaxillary protrusion and the performance advantages it confers are implicated in the success of diverse lineages of teleost fishes, such as Cypriniformes and Acanthomorpha. Although premaxillary protrusion has evolved independently at least five times within bony fishes, much of the functional work investigating this kinesis relates to mechanisms found only in these two clades. Few studies have characterized feeding mechanisms in less‐diverse premaxilla‐protruding lineages and fewer yet have investigated the distinctive anatomy underlying jaw kinesis in these lineages. Here, we integrated dissection, clearing and staining, histology, micro‐CT, and high‐speed videography to investigate an isolated and independent origin of jaw protrusion in the hingemouth, Phractolaemus ansorgii, which employs a complex arrangement of bones, musculature, and connective tissues to feed on benthic detritus via a deployable proboscis. Our goals were to provide an integrative account of the underlying architecture of P. ansorgii's feeding apparatus and to assess the functional consequences of this drastic deviation from the more typical teleost condition. Phractolaemus ansorgii's cranial anatomy is distinct from all other fishes in that its adducted lower jaw is caudally oriented, and it possesses a mouth at the terminal end of an elongated, tube‐like proboscis that is unique in its lack of skeletal support from the oral jaws. Instead, its mouth is supported primarily by hyaline‐cell cartilage and other rigid connective tissues, and features highly flexible lips that are covered in rows of keratinous unculi. Concomitant changes to the adductor musculature likely allow for the flexibility to protrude the mouth dorsally and ventrally as observed during different feeding behaviors, while the intrinsic compliance of the lips allows for more effective scraping of irregular surfaces. From our feeding videos, we find that P. ansorgii is capable of modulating the distance of protrusion, with maximum anterior protrusion exceeding 30% of head length. This represents a previously undescribed example of extreme jaw protrusion on par with many acanthomorph species. Protrusion is much slower in P. ansorgii—reaching an average speed of 2.74 cm/s—compared to acanthomorphs feeding on elusive prey or even benthivorous cypriniforms. However, this reorganization of cranial anatomy may reflect a greater need for dexterity to forage more precisely in multiple directions and on a wide variety of surface textures. Although this highly modified mechanism may have limited versatility over evolutionary timescales, it has persisted in solitude within Gonorynchiformes, representing a novel functional solution for benthic feeding in tropical West African rivers. [ABSTRACT FROM AUTHOR]

Objective: The aim of the studywas to evaluate the influence of repeated sprints on kinematic performance and propulsion variables during the acceleration and constant peak velocity phases in wheelchair rugby players classified as defensive (low point in defensive [LP-D]) or offensive players (high point in offensive [HP-O]). Design: Twenty-two players (13 LP-D and 9 HP-O) performed 6° 20-m repeated sprint field tests. We calculated peak wheelchair velocities, propulsion phase times, deceleration phase times, cycle times, and left-right velocity asymmetry of the best and last sprints during the acceleration and constant peak velocity phases, the rate of decline in performance variables between the best and the last sprint and a fatigue index. Results: Peak velocities during the acceleration and constant peak velocity phases and mean velocity over thewhole sprint were significantly higher during the best than last sprint. Peak velocities were higher during the acceleration and constant peak velocity phases for the best and last sprint for HP-O. The rate of decline in peak velocity during the constant peak velocity phasewas higher for LP-D. Fatigue index and rate of decline in velocities and sprint time were higher for LP-D. Conclusions: Performance variables and the rate of decline in performance variables depended on functional capacity and wheelchair type. [ABSTRACT FROM AUTHOR]

BACKGROUND: In the last decades, emerging evidence has shown that muscle growth is not homogeneous along a muscle head. This phenomenon is known as regional muscle hypertrophy and has led to several questions regarding the implications it may have for health and sports performance. OBJECTIVE: The aim of this study was to determine whether regional hypertrophy can be predicted by surface electromyography (sEMG). METHODS: 36 participants performed two arm exercises (preacher curls and inclined curls) in a random order to muscle failure at 70% of the 1 RM of the bicep curl exercise. As every participant performed a different number of repetitions, Peak sEMG and the integral of the sEMG of the last 3 repetitions was analyzed an compared to previously performed maximal voluntary isometric contractions (MVIC). RESULTS: The independent sample t -tests showed no significant differences neither in the peak nor in the integral of the sEMG between exercises for any given region. CONCLUSIONS: sEMG cannot be used to predict regional hypertrophy. [ABSTRACT FROM AUTHOR]

BACKGROUD: The control of hip and ankle joint movement is important for patients with dynamic knee valgus (DKV), but few studies have used non-elastic taping (NET) to adjust alignment of the hip and ankle joints during overhead squat (OHS) simultaneously in patients with DKV. OBJECTIVE: We investigated changes in lower extremity joint kinematics and dynamic balance after the application of NET to the hip and ankle joints during OHS. METHODS: A total of 30 DKV patients participated in this study. We determined the kinematics of the hip, knee, and ankle joints, and scores on the lower quarter Y-balance test (YBT-LQ) during OHS under three conditions (non-taping, NET on hip and ankle, and sham taping). RESULTS: Hip internal rotation, knee valgus, and the ankle dorsiflexion angle were significantly lower with NET than with non- or sham taping. The hip flexion angle and scores on the YBT-LQ were significantly greater with NET than with non- or sham taping. CONCLUSIONS: The application of NET while performing a OHS is a useful method for correcting lower extremity alignment in patients with DKV, however, application of NET on the ankle should be considered. [ABSTRACT FROM AUTHOR]

Footwear has the potential to reduce soft‐tissue vibrations (STV) but responses are highly subject‐specific. Recent evidence shows that compressive garments minimizing STV have a beneficial effect on neuromuscular (NM) fatigue. The aim was to determine whether an individualized midsole hardness can minimize STV and NM fatigue during a half marathon. Twenty experienced runners were recruited for three visits: a familiarization session including the identification of midsole minimizing and maximizing STV amplitude (MIN and MAX, respectively), and two half marathon sessions at 95% of speed at the second ventilatory threshold. STV of the gastrocnemius medialis (GM) muscle, running kinetics, foot strike pattern, rating perceived exhaustion (RPE), and midsole liking were recorded every 3 km. NM fatigue was assessed on plantar flexors (PF) before (PRE) and after (POST) the half marathon. At POST, PF central and peripheral alterations and changes in contact time, step frequency, STV median frequency, and impact force frequency as well as foot strike pattern were found in both MIN and MAX. No significant differences in damping, STV main frequency, flight time, duty factor, and loading rate were observed between conditions whatever the time period. During the half marathon, STV amplitude of GM significantly increased over time for the MAX condition (+13.3%) only. Differences between MIN and MAX were identified for RPE and midsole liking. It could be hypothesized that, while significant, the effect of midsole hardness on STV is too low to substantially affect NM fatigue. [ABSTRACT FROM AUTHOR]

Purpose: The pivot‐shift test is used to clinically assess knee instability in patients with anterior cruciate ligament (ACL) lesions; however, it has low interobserver reliability. Dynamic radiostereometry (dRSA) is a highly precise and noninvasive method for the objective evaluation of joint kinematics. The purpose of this study was to quantify precise knee kinematics during a pivot‐shift test using dRSA imaging. Method: Eight human donor legs, including hemipelvises, were evaluated. Arthroscopic intervention was performed inducing ligament lesions in the ACL, and anterolateral ligament (ALL) section was performed as a capsular incision. The pivot‐shift test was recorded with dRSA on knees with intact ligaments, ACL‐deficient and ACL + ALL‐deficient knees. Results: A pivot‐shift pattern was identifiable after ligament lesion, as a change in tibial posterior drawer velocity from 7.8 mm/s (95% CI: 3.7; 11.9) in ligament intact knees to 30.4 mm/s (95% CI 23.0; 38.8) after ACL lesion to 35.1 mm/s (95% CI 23.4; 46.7) after combined ACL‐ALL lesion. The anterior‐posterior drawer excursion increased from 2.8 mm (95% CI 2.1; 3.4) in ligament intact knees to 7.2 mm (95% CI 5.5; 8.9) after ACL lesion to 7.6 mm (95% CI 5.5; 9.8) after combined lesion. A statistically significant increase in tibial external rotation towards the end of the pivot‐shift motion was observed when progressing from intact to ACL + ALL‐deficient knees (p < 0.023). Conclusion: This experimental study demonstrates the feasibility of dRSA to objectively quantify the kinematic laxity patterns of the knee during the pivot‐shift test. The dynamic parameters obtained through dRSA revealed the kinematic changes from ACL to combined ACL‐ALL ligament lesion. Level of Evidence: Not applicable. [ABSTRACT FROM AUTHOR]

For a two-axis fast steering mirror (FSM) based on the flexible chain structure support and voice coil motor drive, the two axes are strongly coupled. This strong coupling may decrease the system positioning accuracy. In this study, the electric kinematics model associated with the voice coil motor and the motion and frequency equations associated with the flexible chain structure were analysed. A comprehensive system model was established considering shaft coupling, a digital controller with compensation coupling was designed, and the method of active compensation was used for decoupling. The experimental results showed that compared with the traditional non-decoupling control algorithm, the decoupling control method decreased the coupling degree from 7% to 0.8% and reduced the positioning accuracy error from 1.5% to 0.3%. • The motion characteristics of the FSM in actual operation are more complex than the conventional kinematic electrical model. • The active compensation method is used to preprocess the output signal, and the coupling is separated from the system to improve the accuracy. • The model after active compensation can be combined with any control algorithms to improve the control accuracy. [ABSTRACT FROM AUTHOR]

A novel six-degree-of-freedom (6-DOF) parallel manipulator (PM) with a 6- P SS configuration is designed as a piston error compensation mechanism in an optical system. To meet the high-precision adjustment requirement, the prismatic hinges are driven by nanometer resolution piezoelectric motors, and hyperbolic–elliptic (H-E) flexure hinges are used as spherical hinges because of their zero clearance and greater precision transmission capability than traditional rigid hinges. The analysis of the closed-loop vector relationship of the kinematic chain of the leg results in the construction of the kinematic equation, which can satisfy the inverse kinematic solution within a certain precision. The Newton–Raphson method is used for the iteration to solve the forward kinematics. A kinematic simulation was performed to verify the accuracy and effectiveness of the kinematic model using the rigid–flexible coupling finite element method. The workspace of the PM was analyzed using inverse kinematics and kinematics simulation. Two test systems were constructed to test the working performance of the PM. The experimental tests demonstrated that the resolution reached the nanometer level and the travel reached the millimeter level. • A 6- P SS parallel manipulator is proposed whose precision can reach nanometer level. • The kinematics model of the parallel manipulator is established. • A hyperbolic-elliptic flexure hinge with good motion accuracy is proposed. • A theoretical model is established to assess different types of flexure hinges. [ABSTRACT FROM AUTHOR]

Studying the detailed biomechanics of flying animals requires accurate three‐dimensional coordinates for key anatomical landmarks. Traditionally, this relies on manually digitizing animal videos, a labor‐intensive task that scales poorly with increasing framerates and numbers of cameras. Here, we present a workflow that combines deep learning–powered automatic digitization with filtering and correction of mislabeled points using quality metrics from deep learning and 3D reconstruction. We tested our workflow using a particularly challenging scenario: bat flight. First, we documented four bats flying steadily in a 2 m3 wind tunnel test section. Wing kinematic parameters resulting from manually digitizing bats with markers applied to anatomical landmarks were not significantly different from those resulting from applying our workflow to the same bats without markers for five out of six parameters. Second, we compared coordinates from manual digitization against those yielded via our workflow for bats flying freely in a 344 m3 enclosure. Average distance between coordinates from our workflow and those from manual digitization was less than a millimeter larger than the average human‐to‐human coordinate distance. The improved efficiency of our workflow has the potential to increase the scalability of studies on animal flight biomechanics. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was fourfold: (1) to quantify acceleration, velocity, and phase overlap for each phase of the stroke cycle (SC) during 200 m front crawl; (2) for each variable, to identify any differences between the four SC phases; (3) to investigate changes in variables during the 200 m; (4) to explore any association between performance and each variable. Methods: Ten swimmers performed a 200 m maximum swim. Four SCs were analyzed, one for each 50 m, using three-dimensional methods. Each SC was split into four phases: entry, pull, push, and recovery. Center of mass (CM) acceleration; maximum, minimum, and average CM velocity; phase duration, and, overlap of a phase of one arm with each phase of the opposite arm were calculated. Results and Conclusion: Phase velocities were positively correlated with performance and decreased during the 200 m. The acceleration data showed high within and between-swimmer variability. When the entry of one arm overlapped with the pull, and sometimes push, phase of the opposite arm, it was propulsive for the whole body. The pull was the slowest phase and overlapped predominantly with the opposite arm's recovery. The push phase was often propulsive for the whole body, regardless of the overlaps with the other arm, and together with the entry were the fastest phases. The recovery of each arm was mostly resistive for the whole body, except the short period of overlap with the opposite arm's push phase. [ABSTRACT FROM AUTHOR]

Post-error slowing (PES), the tendency to slow down a behavioral response after a previous error, has typically been investigated during simple cognitive tasks using response time as a measure of PES magnitude. More recently, PES was investigated during a single reach-to-grasp task to determine where post-error adjustments are employed in a more ecological setting. Kinematic analyses in the previous study detected PES during pre-movement planning and within the grasping component of movement execution. In the current study (N = 22), we increased the cognitive demands of a reach-to-grasp task by adding a choice between target and distractor locations to further explore PES, and other post-error adjustments, under different task conditions. We observed a significant main effect of task condition on overall reaction time (RT); however, it did not significantly impact PES or other post-error adjustments. Nonetheless, the results of this study suggest post-error adjustment is a flexible process that can be observed during pre-movement planning and within the onset and magnitude of the reaching component, as well as in the magnitudes of the grasping component. Considering the sum of the results in the context of existing literature, we conclude that the findings add support to a functional account of error reactivity, such that post-error adjustments are implemented intentionally to improve performance. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the criterion validity of the Hawkin Dynamics (HD) wireless dual force platform system for assessing vertical countermovement jump (CMJ) variables, compared with those derived from a Kistler piezoelectric laboratory grade force platform system. During a single testing session, HD force platforms were placed directly on top of 2 adjacent Kistler force platforms to simultaneously collect vertical ground reaction forces produced by 2 male recreational soccer players (age: 29.0 ± 2.8 years, height: 1.79 ± 0.01 m, mass: 85.6 ± 4.7 kg) that performed 25 vertical CMJs each. Sixteen vertical CMJ variables pertaining to jump height (JH), flight time (FT), time-to-take off (TTT), countermovement depth, body weight (BW), propulsive and braking mean, and peak powers, forces, and impulses were compared between systems. Fixed bias was observed for 6 of 16 variables (peak and mean braking power, mean propulsion force, III, FT, and BW), while proportional bias was present for 10 of 16 variables (peak and mean propulsive and braking force, TTT, FT, peak and mean braking power, mean propulsive power, and BW). For all variables regardless of fixed or proportional bias, percentage differences were ≤3.4% between force platform systems, with near perfect to perfect correlations (r or ρ = 0.977-1.000) observed for 15 of 16 variables. The HD dual wireless force platform system can be considered a valid alternative to a piezoelectric laboratory grade force platform system for the collection of vertical CMJ variables, particularly outcome (i.e., JH, reactive strength index modified) and strategy variables (countermovement depth). [ABSTRACT FROM AUTHOR]

The unique physical profile of each player's role in sub-elite women's cricket is vital for optimizing performance as these players progress to the elite levels. This quantitative, cross-sectional study investigates the physical profiles of sub-elite women's cricket players as a group and compares these profiles across different player roles. Sub-elite female cricket players in the South African domestic women's cricket league were included in this study. A battery of physical assessments were conducted at the start of the 2022/23 season. The physical assessments included body composition, individual muscle strength testing using dynamometry, 2-km time trial (TT), countermovement jump (CMJ), single-leg jump (SLJ), isometric mid-thigh pull, push-up, and hop test on force plates. A total of 44 female players (20.86 ± 1.6 years) were included in the study. Differences were found in muscle mass (p = 0.004) and peak power (p = 0.040) for all-rounders and bowlers. Player roles presented with different dominant (p = 0.006) and non-dominant (p = 0.066) knee flexion strength. The bowlers' body composition and physical strength profile are compromised compared with batters and all-rounders. There were several physical strength and power differences between pace and spin bowlers in CMJ and SLJ tests for jump height (p = 0.009) and peak power (p = 0.006). Batters performed the best in the 2-km TT. Body composition and musculoskeletal profiles for each player role can be baseline markers in sub-elite women's cricket. Stakeholders can use this information to guide physical preparation for players advancing to elite levels. [ABSTRACT FROM AUTHOR]

Both running performance and injury have been associated with running kinematics. Plyometric training improves run performance and reduces injury risk in court-sport and field-sport athletes. The aim of this study was to assess longitudinal changes in kinematics in novice runners before and after a typical beginners' running program, compared with those who perform a plyometric intervention before running. Fifty-seven novice female runners were assigned to the control group (8 weeks walking +8 weeks running) or the intervention group (8 weeks strength or plyometric training +8 weeks running). Kinematics were assessed at baseline, 8 weeks, and 16 weeks. Joint angles throughout the stride of those who completed the training (n = 21) were compared between groups and assessment time points using a statistical parametric mapping 2-way analysis of variance, with group and study time point as independent variables. There was no interaction effect of group and study time point (p > 0.05), indicating that both training programs had similar effects on running kinematics. There was a main effect of time for sagittal plane knee and hip kinematics (p < 0.001); after training, subjects ran with a more extended leg, particularly during swing. Programs of 8 weeks of preparatory training, followed by 8 weeks of running, resulted in altered sagittal plane biomechanics, which have previously been related to improved running economy. A greater volume of plyometric, run training or concurrent plyometric and run training may be required to elicit changes in running form associated with lower injury risk. [ABSTRACT FROM AUTHOR]

Previous plasticity models for predicting anchor kinematics under eccentric loading in clay are mostly rigid plastic. They may produce inaccurate outcomes in some conditions. This paper presents an elastoplastic model to address this issue. Closed-form solutions for anchor velocities are derived considering two types of boundary conditions: the padeye (1) fastened to a mooring chain, with the chain behavior modeled; or (2) hinged to a rigid rod. Compared with previous methods, the proposed method more realistically captures the soil behavior while avoiding complicated iterative procedures for solving anchor velocities, thus enabling anchor trajectories to be accurately and efficiently obtained by simple time integration. A series of 3D large deformation finite element analyses are conducted to study the anchor behaviors under different eccentric loading, and the proposed model is used to reproduce these simulations. Their results are compared for validation, with good agreements achieved. These results indicate that anchors under eccentric loading will ultimately translate along a fixed direction with constant soil reaction forces. Analytical solutions for this ultimate state are given based on the proposed method. Particularly, the ultimate resultant soil reaction force is demonstrated always passing through the anchor center. This is an assumption in a previous literature but is found to be a consequence of the proposed anchor constitutive relations. [ABSTRACT FROM AUTHOR]

Therapeutic interventions for individuals with chronic ankle instability (CAI) are recommended to improve muscle strength, postural control, and range of motion. However, their effects on neuromechanics during a drop landing remain unclear. In addition, even though therapeutic interventions with stroboscopic glasses appear to effectively improve postural control, how they affect landing neuromechanics remains unclear. To identify the effect of balance training with stroboscopic glasses on neuromechanics during a single-legged drop landing in patients with CAI. Randomized controlled clinical trial. Laboratory. A total of 50 participants with CAI were randomly assigned to 1 of 2 groups: strobe (n = 25; age = 22 ± 3 years, height = 174.7 ± 8.2 cm, mass = 71.8 ± 12.2 kg) or control (n = 25; age = 21 ± 2 years, height = 173.1 ± 8.3 cm, mass = 71.1 ± 13.5 kg). The 4-week rehabilitation (3 sessions per week) included hop-based tasks and single-legged stance. The strobe group wore stroboscopic glasses during the training, whereas the control group did not. Ankle-, knee-, and hip-joint kinematics and 4 lower extremity muscle activations 150 milliseconds before and after initial contact during a single-legged drop landing in the 2 groups. The strobe group showed greater eversion (from 150 milliseconds before to 30 milliseconds after initial contact) and dorsiflexion (from 30 to 96 milliseconds after initial contact) angles and peroneal longus (from 35 milliseconds before to 5 milliseconds after initial contact) and tibialis anterior (from 0 to 120 milliseconds after initial contact) activation in the posttest than the pretest. Patients with CAI who underwent a 4-week rehabilitation with stroboscopic glasses demonstrated changes in neuromechanics, including increased ankle-dorsiflexion and -eversion angles and tibialis anterior and peroneus longus activation, during a single-legged drop landing. This finding suggests that use of stroboscopic glasses during rehabilitation could help patients with CAI develop safe landing mechanics. [ABSTRACT FROM AUTHOR]

Individuals with shoulder impingement syndrome (SIS) exhibit changes in corticospinal excitability, scapular kinematics, and scapular muscle-activation patterns. To restore the scapular kinematics and muscle-activation patterns in individuals with SIS, treatment protocols usually include scapula-focused exercises, such as scapular-orientation and strength training. To investigate whether scapular-orientation and strength training can reverse the altered corticospinal excitability of recreational overhead athletes with SIS. Randomized controlled clinical trial. University laboratory. Forty-one recreational overhead athletes with SIS: 20 in the scapular-orientation group (age = 26.45 ± 4.13 years, height = 171.85 ± 7.88 cm, mass = 66.70 ± 10.68 kg) and 21 in the strengthening group (age = 26.43 ± 5.55 years, height = 171.62 ± 5.87 cm, mass = 68.67 ± 10.18 kg). Both groups performed a 30-minute training protocol consisting of 3 exercises to strengthen the lower trapezius (LT) and serratus anterior muscles without overactivating the upper trapezius muscles. Participants in the scapular-orientation group were instructed to consciously activate their scapular muscles with electromyographic biofeedback and cues, whereas the strengthening group did not receive biofeedback or cues for scapular motion. Corticospinal excitability was assessed using transcranial magnetic stimulation. Scapular kinematics and muscle activation during arm elevation were also measured. After training, both groups demonstrated an increase in motor-evoked potentials in the LT (P =.004) and increases in scapular upward rotation (P =.03), LT activation (P <.001), and serratus anterior activation (P <.001) during arm elevation. Moreover, the scapular-orientation group showed higher LT activation levels during arm elevation after training than the strengthening group (P =.03). With or without biofeedback and cues, scapula-focused exercises improved scapular control and increased corticospinal excitability. Adding biofeedback and cues for scapular control during exercise helped facilitate greater LT activation, so feedback and cues are recommended during scapula-focused training. [ABSTRACT FROM AUTHOR]

Guardian Caps (GCs) are currently the most popular external helmet add-on designed to reduce the magnitude of head impacts experienced by American football players. Guardian Caps have been endorsed by influential professional organizations; however, few studies evaluating their efficiency are publicly available. To present preliminary on-field head kinematics data for National Collegiate Athletic Association (NCAA) Division I American football players using instrumented mouthguards through closely matched preseason workouts with and without GCs. Case series. The 2022 American football preseason. Twenty-five male NCAA Division I student-athletes participating in American football completed some portion of the 6 workouts included in this study. Of the 25 participants, 7 completed all 6 workouts using their instrumented mouthguards. Peak linear acceleration (PLA), peak angular acceleration (PAA), and total impacts were collected via instrumented mouthguards during 3 preseason workouts using traditional helmets (TRAD condition) and 3 using a TRAD and GCs (GC condition). The TRAD and GC values for PLA, PAA, and total impacts were evaluated using analyses of variance. No difference was present between the collapsed mean values for the entire sample between the TRAD and GC conditions for PLA (TRAD = 16.3g ± 2.0g, GC = 17.2g ± 3.3g, P =.20), PAA (TRAD = 992.1 ± 209.2 rad/s2, GC = 1029.4 ± 261.1 rad/s2, P =.51), or the total number of impacts (TRAD = 9.3 ± 4.7, GC = 9.7 ± 5.7, P =.72). Similarly, no difference was observed between the TRAD and GC conditions for PLA (TRAD = 16.1g ± 1.2g, GC = 17.2g ± 2.79g, P =.32), PAA (TRAD = 951.2 ± 95.4 rad/s2, GC = 1038.0 ± 166.8 rad/s2, P =.29), or total impacts (TRAD = 9.6 ± 4.2, GC = 9.7 ± 5.04, P =.32) between sessions for the 7 players who completed all 6 workouts. These data suggested no difference in head kinematics data (PLA, PAA, and total impacts) when GCs were worn. Therefore, GCs may not be effective in reducing the magnitude of head impacts experienced by NCAA Division I American football players. [ABSTRACT FROM AUTHOR]

The neurocognitive health effects of repetitive head impacts have been examined in many sports. However, characterizations of head impacts for sliding-sport athletes are lacking. To describe head impact kinematics and injury epidemiology in elite athletes during the 2021–2022 Bobsleigh World Cup season. Cross-sectional study. On-track training and competitions during the Bobsleigh World Cup season. Twelve elite bobsleigh athletes (3 pilots [1 female], 9 push athletes [5 females]; age = 30 ± 5 years; female height and weight = 173 ± 8 cm and 75 ± 5 kg, respectively; male height and weight = 183 ± 5 cm and 101 ± 5 kg, respectively). Athletes wore an accelerometer-enabled mouthguard to quantify 6-degrees-of-freedom head impact kinematics. Isometric absolute and relative neck strength, number of head acceleration events (HAEs), workload (J), peak linear velocity (m·s−1), peak angular velocity (rad·s−1), peak linear acceleration (g), and peak angular acceleration (rad·s−2) were derived from mouthguard manufacturer algorithms. Linear mixed-effect models tested the effects of sex (male versus female), setting (training versus competition), and position (pilot versus push athlete) on the kinematic variables. A total of 1900 HAEs were recorded over 48 training and 53 competition days. No differences were found between the number of HAEs per run per athlete by sex (incidence rate ratio [IRR] = 0.82, P =.741), setting (IRR = 0.94, P =.325), or position (IRR = 1.64, P =.463). No sex differences were observed for workload (mean ± SD: males = 3.3 ± 2.2 J, females = 3.1 ± 1.9 J; P =.646), peak linear velocity (males = 1.1 ± 0.3 m·s−1, females = 1.1 ± 0.3 m·s−1; P =.706), peak angular velocity (males = 4.2 ± 2.1 rad·s−1, females = 4.7 ± 2.5 rad·s−1; P =.220), peak linear acceleration (male = 12.4 ± 3.9g, females = 11.9 ± 3.5g; P =.772), or peak angular acceleration (males = 610 ± 353 rad·s−2, females = 680 ± 423 rad·s−2; P =.547). Also, no effects of setting or position on any kinematic variables were seen. Male athletes had greater peak neck strength than female athletes for all neck movements, aside from right-side flexion (P =.085), but no sex differences were noted in relative neck strength. We provide a foundational understanding of the repetitive HAEs that occur in bobsleigh athletes. Future authors should determine the effects of repetitive head impacts on neurocognitive function and mental health. [ABSTRACT FROM AUTHOR]

The decline in cognitive function in older adults with mild cognitive impairment (MCI) may contribute to a change in movement pattern during sit-to-stand transitions (STS). However, when comparing older adults with MCI to older adults without MCI, there is a lack of evidence of kinematic and kinetic data during STS. Furthermore, while significant cognitive dual-task interference has been demonstrated in older adults with MCI, studies on the effects of dual motor tasks in MCI, particularly during STS, have not been reported. Are there any differences in the movement time, joint angles, and maximum joint moments while performing STS under single- and dual-task conditions in older adults with and without MCI? In a cross-sectional study, 70 participants were divided into two groups: older adults with MCI and without MCI. Motion analysis and a force plate system were used to collect and analyze the STS movement. All participants were asked to do the STS movement alone and the STS with a dual motor task with the self-selected pattern on an adjustable bench. Older adults with MCI had greater maximum trunk flexion during STS with a dual task than older adults without MCI and greater than STS alone. Furthermore, older adults with MCI had a greater ankle plantar flexion moment during STS with a dual task than during STS alone. Even though the STS task is one of the simplest functional activities, different strategies to achieve the STS action with dual tasks were found among older adults with and without MCI in terms of joint angle and joint moments. • The time used for STS showed no difference between older adults with and without MCI. • STS with dual tasks spent more time to complete than STS alone. • Older adults with MCI perform more trunk flexion during STS with dual tasks. • Older adults with MCI rely on the ankle plantar flexor during STS with dual tasks. [ABSTRACT FROM AUTHOR]

As total ankle arthroplasty (TAA) is an increasingly common surgical intervention for patients with end-stage ankle arthritis, there is a need to better understand the dynamic performance of prosthetic implants during activities of daily living. Our purpose was to quantify and compare relative tibiotalar motion during gait in persons with a fixed-bearing (FB) and mobile-bearing (MB) total ankle arthroplasty. We hypothesized a FB prosthesis would have lower tibiotalar range of motion (ROM). Patients at least 12 months postoperative with either a FB (n=5) or MB (n=3) total ankle arthroplasty were tested. We used high-speed biplanar videoradiography to quantify tibiotalar kinematics during self-selected gait. Angular and linear ROM in three axes were compared between the groups. ROM for dorsiflexion-plantarflexion, internal-external rotation, and inversion-eversion angles in FB subjects averaged 7.47±4.05°, 7.39±3.63°, and 4.51±2.13°, respectively. ROM in MB subjects averaged 6.74±2.04°, 6.28±4.51°, and 5.68±2.81°, respectively. Linear ROM along anteroposterior, mediolateral, and superior-inferior axes in FB subjects averaged 1.47±2.07 mm, 1.13±1.49 mm, and 0.28±0.30 mm, respectively. Linear ROM in MB subjects averaged 0.68±1.44 mm, 0.60±1.41 mm, and 0.20±0.13 mm, respectively. We found no significant difference between the two groups for any of these ROM parameters (p>0.05). Total ankle arthroplasty using either FB or MB design appears to confer similar ankle motion during the gait cycle in this biplanar fluoroscopic model. Level IV, case series. • X-ray motion analysis is a useful tool to compare ankle arthroplasty systems. • No differences in angular motion between MB and FB arthroplasty systems. • No significant difference in linear translation along joint axes in both systems. [ABSTRACT FROM AUTHOR]

Clinical gait analysis (CGA) is a systematic approach to comprehensively evaluate gait patterns, quantify impairments, plan targeted interventions, and evaluate the impact of interventions. However, international standards for CGA are currently lacking, resulting in various national initiatives. Standards are important to ensure safe and effective healthcare practices and to enable evidence-based clinical decision-making, facilitating interoperability, and reimbursement under national healthcare policies. Collaborative clinical and research work between European countries would benefit from common standards. This study aimed to review the current laboratory practices for CGA in Europe. A comprehensive survey was conducted by the European Society for Movement Analysis in Adults and Children (ESMAC), in close collaboration with the European national societies. The survey involved 97 gait laboratories across 16 countries. The survey assessed several aspects related to CGA, including equipment used, data collection, processing, and reporting methods. There was a consensus between laboratories concerning the data collected during CGA. The Conventional Gait Model (CGM) was the most used biomechanical model for calculating kinematics and kinetics. Respondents also reported the use of video recording, 3D motion capture systems, force plates, and surface electromyography. While there was a consensus on the reporting of CGA data, variations were reported in training, documentation, data preprocessing and equipment maintenance practices. The findings of this study will serve as a foundation for the development of standardized guidelines for CGA in Europe. • Survey report on current Clinical Gait Analysis (CGA) practices across Europe. • Good agreement on data included in CGA with video, kinematics, kinetics and EMG. • Training, documentation, maintenance, reliability evaluations vary between laboratories. • New gait analysis tools have limited adoption in CGA. • Results set foundation for a Delphi process to define European CGA standards. [ABSTRACT FROM AUTHOR]

The subtalar joint movement between the talus and calcaneus is restricted in patients with talocalcaneal coalition (TCC). When the motion of the subtalar joint is restricted, shock absorption in the foot decreases, leading to pain during walking. Resection methods to maintain subtalar motion by removing abnormal unions have been proposed. The purpose of this study was to analyze the joint kinematics of patients who underwent TCC resection and to quantitatively evaluate the results of the surgery based on the measured kinematics. Joint kinematics of five patients with TCC were obtained using a biplane fluoroscopic imaging system and an intensity-based two-/three-dimensional registration method. The joint kinematics of the tibiotalar and subtalar joints and the tibiocalcaneal motion during the stance phase of walking were obtained. From the kinematics of the hindfoot joints, the inversion/eversion range of motion (ROM) of the patients before and after resection was statistically analyzed using the Wilcoxon signed-rank test to test whether TCC resection improved the ROM. During the loading response period, the eversion ROM of the subtalar joint and tibiocalcaneal motion significantly increased postoperatively. In addition, a significant postoperative increase was observed in the subtalar and tibiocalcaneal inversion ROM during the pre-swing period. TCC resection surgery increased the ROM of the subtalar joint, which in turn contributed to the increase in tibiocalcaneal ROM. Increased subtalar and tibiocalcaneal ROM could result in increased shock attenuation and may be a contributing factor to pain relief during walking. [ABSTRACT FROM AUTHOR]

Individuals with cerebral palsy (CP) often present with altered motor control. This can be assessed selectively during sitting/lying with the Selective Control Assessment of the Lower Extremity (SCALE), or dynamically with the dynamic motor control index during walking (walk-DMC). Both approaches suggest that altered selective motor control relate to larger gait deviations. Does the walk-DMC provide valuable information in addition to the SCALE for estimating gait deviations in individuals with CP. Retrospective, treadmill-based gait analysis data of 157 children with spastic CP (mean 11.4±3.5 years) and Gross Motor Function Classification System levels I (n=45), II (n=88) or III (n=24) were extracted. Gait kinematic deviations were evaluated using the Gait Profile Score (GPS). The SCALE, walk-DMC and GPS were extracted for the more clinically involved leg (unilateral-analysis), and for both legs together (bilateral-analysis). GPS moderately correlated with both SCALE and walk-DMC scores, unilaterally and bilaterally (r≥0.4; p<0.001). Multivariate linear regression analyses were conducted, taking into account potential confounding factors. In the unilateral analysis, 54% of the GPS variance was explained (p<0.001), with both walk-DMC and SCALE significantly contributing to the GPS variance (p=0.006 and p=0.008, respectively). In the bilateral analysis, 61% of the GPS variance was explained (p<0.001), with both walk-DMC and SCALE significantly contributing to the GPS variance (p=0.006 and p<0.001, respectively). Dimensionless walking speed and use of assistive devices were the only confounding factors included in each analysis. Both SCALE and walk-DMC significantly contribute to GPS variance, suggesting that they likely measure different components of motor control, and both may be useful in understanding the underlying relationship between motor control and deviations in gait kinematics. • Both the SCALE and walk-DMC relate to kinematic gait deviations in CP. • The SCALE and walk-DMC likely measure different components of motor control in CP. • In the absence of EMG, the SCALE can be used to quantify motor control in CP. [ABSTRACT FROM AUTHOR]

Currently, cranes used at sea are insufficient in efficiency. Accordingly, a floating multi-robot coordinated towing system is proposed to meet offshore towing needs. However, the towing robot is prone to overturning because of the system's utilization of rope-driven robot flexibility and its floating attributes in fluid environments. First, the kinematics and dynamics of the towing system are analyzed through coordinate transformations and hydrodynamic theory. Subsequently, physical modeling of the towing system is conducted, with an emphasis on analyzing the system's fluid-structure coupling properties, supplemented by illustrative examples. Finally, the stability of the floating robot is assessed based on ship stability theory, encompassing analyses of the rope tension effects, size and shape of the floating base, and external environmental factors influencing system stability. Results show that the special shape of the floating base is beneficial in reducing water resistance and improving the stability of the floating robot in the flow field. The results provide a good basis for the system structural design and application. [ABSTRACT FROM AUTHOR]

The Clarke River Shear Zone marks the boundary between the Thomson and Mossman orogens in the northeastern Tasmanides. To better understand the kinematic history of this east-northeast-trending shear zone, and its role during the tectonic history of eastern Gondwana, we investigated rock deformation along a segment of the Clarke River Shear Zone. Based on field observations, interpretation of aeromagnetic data and microstructural analysis, we show that the Clarke River Shear Zone experienced at least three phases of reactivation. Gently plunging stretching lineation and kinematic indicators, such as steeply plunging asymmetric folds and asymmetric porphyroclasts, correspond to an early phase of sinistral strike-slip ductile shearing. Subsequent general dextral shear deformation is suggested based on the presence of S-tectonites, symmetric porphyroclasts and kinematic indicators with dominant dextral and subordinate sinistral shear senses. This phase, which occurred under amphibolite-facies metamorphic conditions, was contemporaneous with the emplacement of the Craigie Tonalite, for which we obtained a new zircon U–Pb crystallisation age of 410.3 ± 1 Ma. A later reactivation phase along the Clarke River Shear Zone, under brittle conditions, is indicated by the presence of cataclasite zones and chlorite–epidote alteration. Based on our findings, and regional information on the tectono-magmatic evolution of northeastern Queensland, we suggest that the Clarke River Shear Zone was possibly a sinistral transform fault during the Silurian. During the Devonian, it is possible that deformation along the Clarke River Shear Zone was related to the transition between the non-retreating subduction zone in the north, and the highly mobile (retreating) plate boundary farther south. However, the dextral kinematic component associated with this deformation is not fully explained. Brittle deformation, likely associated with dextral transpression during the Carboniferous, marked the last stage of activity along the Clarke River Shear Zone. The Clarke River Shear Zone records three phases of reactivation during the Silurian–Carboniferous. Ductile dextral general shear deformation along the Clarke River Shear Zone occurred at ca 410 Ma, based on zircon U–Pb dating of a syn-tectonic intrusion. The Clarke River Shear Zone likely accommodated subduction segmentation during the Silurian–Devonian. [ABSTRACT FROM AUTHOR]

Background: Optimal management and surgical planning of severe bony deformities and muscle tendon unit contractures demands comprehensive evaluation of all structures including the dynamic muscle tendon length of all muscles around the joint during gait. Objectives: Present study aimed to explore dynamic muscle–tendon length for all muscles around the knee joint along with pelvis, hip, and ankle joint kinematics among adolescent children with varying crouch angle. Methods: Muscle–tendon length of 29 adolescent children with cerebral palsy with varying crouch angles was computed using a full-body musculo-skeletal model and expressed as a percentage of muscle–tendon length during walking compared to resting condition. Results: Children with knee flexion angle greater than 25° demonstrated lower anterior pelvic tilt and 11% greater muscle–tendon length of semimembranosus and biceps femoris during stance phase of gait compared to children with knee flexion angle less than 25° and typically developing children (p < 0.01). Conclusions: The findings of present study reported that routine bedside clinical evaluation in adolescent children with knee flexion angle greater than 25° revealed moderate shortening of hamstring muscle in supine position. Whereas instrumented objective evaluation of gait demonstrated lengthened hamstring muscle and reduced hip extension and relatively lower anterior pelvic tilt. Therefore, it may be valuable to add objective assessment of dynamic muscle–tendon length to kinematics of all lower-extremity joint motion during gait, in order to understand the muscle–joint interactions; particularly in children with severe crouch and plan specific, tailor-made surgical and non-surgical interventions. [ABSTRACT FROM AUTHOR]