Is larger eccentric utilization ratio associated with poorer rate of force development in squat jump? An exploratory study

This exploratory study examines the relationship between the eccentric utilization ratio (EUR) and the rate of force development (RFD) in squat jumps (SJ). EUR, a key metric in sports science, compares performance in countermovement jumps (CMJ) and squat jumps (SJ). The study hypothesizes that a higher EUR is associated with a poorer RFD in SJ. Basketball and soccer players, long-distance runners, alongside physical education students (209 men; age: 23.2 ± 4.95 years and 104 women; age: 22.7 ± 4.42 years) participated. The EUR was calculated from jump height, peak force and peak power. The results indicated a small to moderate but significant negative correlation between EUR based on peak force or peak power and RFD in SJ (r = -.41 and -.27), suggesting that a higher EUR might be linked to a diminished ability to rapidly develop force in SJ. Thus, a higher EUR may not indicate superior athletic performance.

Health risk assessment and prevalence of work-related musculoskeletal disorders among the aged brick molders, in India

The Brickfield Industry is the major and oldest informal industry in India, where millions of brickfield workers make their livelihood. Aged brickfield workers are also involved in different activities in the brickfield, especially in brick mold activities owing to poor socioeconomic conditions. A cross-sectional study was designed to determine the prevalence of work-related musculoskeletal disorders among the aged brick molders and compare them with aged control subjects. A Nordic Questionnaire was applied to assess the discomfort felt among both groups of workers and the Rapid Upper Limb Assessment (RULA) method was used to evaluate posture during their job. The RULA posture analysis showed that the posture adopted by aged brick molders required changes immediately. The result of the ART tool also stated that the brick molding activities' exposure level was high and required further investigation urgently. The study concluded that due to working in a forward bending posture for a prolonged period, aged brickmolders suffered from severe low back and knee pain along with upper-limb disorders due to repetitive activities.

Geometry-driven self-supervision for 3D human pose estimation

Although 3D human pose estimation has recently made strides, it is still difficult to precisely recreate a 3D human posture from a single image without the aid of 3D annotation for the following reasons. Firstly, the process of reconstruction inherently suffers from ambiguity, as multiple 3D poses can be projected onto the same 2D pose. Secondly, accurately measuring camera rotation without laborious camera calibration is a difficult task. While some approaches attempt to address these issues using traditional computer vision algorithms, they are not differentiable and cannot be optimized through training. This paper introduces two modules that explicitly leverage geometry to overcome these challenges, without requiring any 3D ground-truth or camera parameters. The first module, known as the relative depth estimation module, effectively mitigates depth ambiguity by narrowing down the possible depths for each joint to only two candidates. The second module, referred to as the differentiable pose alignment module, calculates camera rotation by aligning poses from different views. The use of these geometrically interpretable modules reduces the complexity of training and yields superior performance. By adopting our proposed method, we achieve state-of-the-art results on standard benchmark datasets, surpassing other self-supervised methods and even outperforming several fully-supervised approaches that heavily rely on 3D annotations.

Knee wobbling during the single-leg-squat-and-hold test reflects dynamic knee instability in patients with anterior cruciate ligament injury

We propose using the single-leg squat-and-hold (SLSH) task with kinematic analysis to objectively measure dynamic knee stability after anterior cruciate ligament (ACL) injury. There are three objectives of this study: to compare the knee kinematics of ACL-deficient patients and healthy controls by capturing knee wobbling during the SLSH task, to detect kinematic changes after ACL reconstruction, and to correlate the kinematic variables with self-reported knee function. Twenty-five ACL-deficient participants and 18 healthy matched participants were recruited. The knee kinematics involving both the magnitudes and frequency of motion fluctuation was captured during SLSH by 3D motion analysis system (Vicon). Compared to the limbs of the control participants, the ACL involved limbs exhibited a greater range of flexion-extension (4.33 ± 1.96 vs. 2.73 ± 1.15; p = 0.005) and varus-valgus (2.52 ± 0.99 vs. 1.36 ± 0.42; p < 0.001). It also inhibited higher frequency of flexion-extension (4.87 ± 2.55 vs. 2.68 ± 1.23; p = 0.003) and varus-valgus (3.83 ± 2.59 vs. 1.42 ± 0.55; p < 0.001). The range of flexion-extension (4.50 ± 2.24 vs. 2.90 ± 1.01; p = 0.018), frequency of flexion-extension (4.58 ± 2.53 vs. 3.05 ± 1.80; p = 0.038) and varus-valgus (3.46 ± 2.11 vs. 1.80 ± 1.23; p = 0.022) was reduced after ACL reconstruction. Increased frequency of knee varus-valgus was correlated with lower IKDC score (r = -0.328; p = 0.034). Knee wobbling was more prominent in ACL-deficient patients, which was associated with poor knee function. SLSH task with kinematic analysis appears to be a potential assessment method for monitoring dynamic knee stability after ACL injury.

Variation of thoracolumbar vertebral morphology in anthropoid primates

OBJECTIVES

Morphological variation among extant primates in the lumbar vertebral column is well studied. However, knowledge concerning the thoracic spine, an important region responsible for supporting and facilitating movement in the upper trunk, remains relatively scarce. Consequently, our comprehension of the functional differentiation exhibited throughout the thoracolumbar vertebral column among various primate species remains constrained. In this study, we examined patterns of morphological variation in the thoracolumbar vertebral column of extant hominoids, cercopithecoids, and Ateles.

MATERIALS AND METHODS

We collected external shape data on 606 thoracic and lumbar vertebrae from Homo sapiens, Pan troglodytes, Hylobates lar, Macaca fuscata, Chlorocebus aethiops, Colobus guereza, Ateles geoffroyi, and A. belzebuth. Forty-four landmarks were obtained on the three-dimensional surface. Geometric morphometrics was used to quantify the centroid size and variation of the shapes of thoracic and lumbar vertebrae.

RESULTS

Cercopithecoids exhibited greater variation in the size and shape of their thoracic and lumbar vertebrae compared to hominoids and Ateles. Although many vertebral features contributed to the observed variation throughout the thoracolumbar vertebral column within the taxon, the transverse and spinous processes exhibited relatively major contributions.

DISCUSSION

Our results suggest that quadrupedal locomotion requires the functional differentiation between thoracic and lumbar vertebrae, and for hominoids, functional adaptation to orthograde posture necessitates a relatively more uniform shape of thoracic and lumbar vertebrae.

The National Institute for Occupational Safety and Health (NIOSH) Recommended Weight Generates Different Spine Loads in Load-Handling Activity Performed Using Stoop, Semi-squat and Full-Squat Techniques; a Full-Body Musculoskeletal Model Study

OBJECTIVE

Adequacy of the Revised NIOSH Lifting Equation (RNLE) in maintaining lumbosacral (L5-S1) loads below their recommended action limits in stoop, full-squat, and semi-squat load-handling activities was investigated using a full-body musculoskeletal model.

BACKGROUND

The NIOSH committee did not consider the lifting technique adapted by workers when estimating the recommended weight limit (RWL). It is currently unknown whether the lifting technique adapted by workers would affect the competence of the RNLE in keeping spine loads below their recommended limits.

METHOD

A full-body subject-specific musculoskeletal model (Anybody Modeling System, AMS) driven by a 10-camera Vicon motion capture system (Vicon Motion Systems Inc., Oxford, UK) was used to simulate different static stoop, semi-squat, and full-squat load-handling activities of ten normal-weight volunteers (mean of ∼70 kg corresponding to the 15th percentile of adult American males) with the task-specific NIOSH RWL held in hands.

RESULTS

Two-way repeated measures ANOVA revealed a significant effect of lifting technique on both the L5-S1 compression (p = 0.003) and shear (p = 0.004) loads with semi-squat technique resulting in significantly larger loads than both stoop and full-squat techniques (p < 0.05). While mean of L5-S1 loads remained smaller than their recommended limits, it is much expected that they pass these limits for heavier individuals, that is, for the 50th percentile of adult American males.

CONCLUSION

Spinal loads are expected to pass their recommended limits for heavier individuals especially during semi-squat lifting as the most frequently adapted technique by workers.

APPLICATION

Caution is required for the assessment of semi-squat lifting activities by the RNLE.

Symmetrical activity of the chewing muscles and its relationship with skeletal class and body posture

OBJECTIVE

To describe the role of body posture and skeletal class in the symmetrical activity of chewing muscles.

METHODS

Descriptive study with association. Skeletal class measured by the Steiner method. Postural analysis through APECS mobile application for forward head posture and shoulder discrepancy, and surface electromyography with Biopac® device.

RESULTS

The skeletal class, forward head posture, and shoulder discrepancy presented statistical association with the symmetrical electromyographic response of digastric muscles and masseter muscles during swallowing.

DISCUSSION

This study exhibited a positive relationship between digastric muscle symmetry and skeletal class during swallowing. The compensation of the hyoid system explains these results, showing that skeletal Class III has better electromyographic balance. In contrast, masseter muscle symmetry during swallowing presented a negative relationship with skeletal class. The stabilization role that this muscle plays during swallowing explains these findings, caused by the different lengths and direction of this muscle in skeletal Class III.

Hip joint contact forces are lower in people with femoroacetabular impingement syndrome during squat tasks

It remains unknown if hip joint forces during squat tasks are altered in people with femoroacetabular impingement syndrome (FAIS). The aim of this study is to compare hip joint forces between people with FAIS and healthy controls during double leg squat and single leg squat tasks and within limbs during a single leg squat task in people with FAIS. Kinematic and kinetic data were collected in eight people with FAIS and eight healthy matched controls using 3D motion capture and force plates. AnyBody Modeling System was used to perform musculoskeletal simulations to estimate hip joint angles, forces, and moments for all participants. Estimates were postprocessed with AnyPyTools and converted into normalized time series to be compared using a 1D statistical nonparametric mapping (SnPM) approach. SnPM with an independent samples t-test model was used to compare people with FAIS to controls, while a paired samples model was used to compare involved to uninvolved limb in people with FAIS. Patients demonstrated lower proximodistal force compared to controls (p < 0.01) and compared to the uninvolved side (p = 0.01) for single leg squat. The smaller joint contact forces in people with FAIS compared to controls could represent a strategy of reduced muscle forces to avoid pain and symptoms during this high demand task. These findings when combined with imaging data could help assess the severity of FAIS on hip related function during higher demand tasks.

A rare case of extensive neurogenic heterotopic ossification: a case report

INTRODUCTION

Neurogenic Heterotopic ossification (NHO) is a potential sequalae and a detrimental complication following neurological insult. It is characterized by formation of localized gradually progressive, peri-articular lamellar bone formation in extra-skeletal tissues. We would like to report a rare case of heterotopic ossification involving all 4 limbs, in which we tried to restore joint mobility to improve his functional status so that he could perform his daily tasks.

CASE PRESENTATION

We present a case of a 33-year-old bed ridden male, diagnosed with NHO involving all 4 limbs (bilateral hip, right knee, right shoulder, left elbow). The patient had a crippled posture, significant pain and impaired range of motion hampering movement of all four limbs which prevented him from lying down supine, sitting, walking and performing activities of daily living. After three surgeries, the patient achieved wheelchair mobilization and upright posture with the assistance of calipers.

CONCLUSION

The management of NHO requires a multidisciplinary approach involving orthopaedic surgeons, neurologists & rehabilitation specialists. Prognosis of NHO depends on factors such as extent of ossification, underlying neurological condition & patients overall health.

Development of the Korean construction job exposure matrix (KoConJEM) based on experts' judgment using the 60 consolidated occupations for construction workers

BACKGROUND

This study was conducted as an effort to develop a Korean construction job exposure matrix (KoConJEM) based on 60 occupations recently consolidated by the construction workers mutual aid association for use by the construction industry.

METHODS

The probability, intensity, and prevalence of exposure to 26 hazardous agents for 60 consolidated occupations were evaluated as binary (Yes/No) or four categories (1 to 4) by 30 industrial hygiene experts. The score for risk was calculated by multiplying the exposure intensity by the prevalence of exposure. Fleiss' kappa for each hazardous agent and occupation was used to determine agreement among the 30 experts. The JEM was expressed on a heatmap and a web-based dashboard to facilitate comparison of factors affecting exposure according to each occupation and hazardous agent.

RESULTS

Awkward posture, heat/cold, heavy lifting, and noise were hazardous agents regarded as exposure is probable by at least one or more experts in all occupations, while exposure to asphalt fumes was considered hazardous in the smallest number of occupations (n = 5). Based on the degree of agreement among experts, more than half of the harmful factors and most occupations showed fair to good results. The highest risk value was 16 for awkward posture for most occupations other than safety officer.

CONCLUSIONS

The KoConJEM provides information on the probability, intensity, and prevalence of exposure to harmful factors, including most occupations employing construction workers; therefore, it may be useful in the conduct of epidemiological studies on assessment of health risk for construction workers.

Susceptibility of optic nerve head in children with posture-related elevation of intraocular pressure

BACKGROUND/AIMS

This work aimed to investigate changes in optic nerve head (ONH) morphometry based on Bruch membrane opening in children with extensive nocturnal intraocular pressure (IOP) elevations.

METHODS

The course of Bruch membrane opening-based optic nerve head (ONH) morphometry was analysed in thirty-two patients younger than 18 years with evaluable SD-OCT examinations of the ONH and nocturnal posture-dependent IOP elevation above 25 mmHg. Longitudinal changes in neuroretinal rim tissue, as measured by Bruch Membrane opening minimum rim width (BMO-MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness, were assessed.

RESULTS

One year after the 24 h IOP measurement, global BMO-MRW (- 1.61 ± 16.8 µm, n.s.; p = 0.611) and RNFL (+ 0.64 ± 3.17 µm; n.s.; p = 0.292) measurements were not significantly different from the baseline. No significant BMO-MRW reduction (- 3.91 ± 24.3 µm; n.s. p = 0.458) or deviation in RNFL thickness (+ 1.10 ± 3.52 µm) was observed at the four-year follow-up. Absolute IOP values measured in the supine position did not correlate with changes in global BMO-MRW or RNFL thickness.

CONCLUSION

Posture-dependent IOP elevations do not seem to influence retinal nerve fibre layer thickness or Bruch membrane opening-based morphometric data in childhood.

Enhancing stance robustness and jump height in bipedal muscle-actuated systems: a bioinspired morphological development approach

Recognizing humans' unmatched robustness, adaptability, and learning abilities across anthropomorphic movements compared to robots, we find inspiration in the simultaneous development of both morphology and cognition observed in humans. We utilize optimal control principles to train a muscle-actuated human model for both balance and squat jump tasks in simulation. Morphological development is introduced through abrupt transitions from a 4 year-old to a 12 year-old morphology, ultimately shifting to an adult morphology. We create two versions of the 4 year-old and 12 year-old models- one emulating human ontogenetic development and another uniformly scaling segment lengths and related parameters. Our results show that both morphological development strategies outperform the non-development path, showcasing enhanced robustness to perturbations in the balance task and increased jump height in the squat jump task. Our findings challenge existing research as they reveal that starting with initial robot designs that do not inherently facilitate learning and incorporating abrupt changes in their morphology can still lead to improved results, provided these morphological adaptations draw inspiration from biological principles.

Brownian processes in human motor control support descending neural velocity commands

The motor neuroscience literature suggests that the central nervous system may encode some motor commands in terms of velocity. In this work, we tackle the question: what consequences would velocity commands produce at the behavioral level? Considering the ubiquitous presence of noise in the neuromusculoskeletal system, we predict that velocity commands affected by stationary noise would produce "random walks", also known as Brownian processes, in position. Brownian motions are distinctively characterized by a linearly growing variance and a power spectral density that declines in inverse proportion to frequency. This work first shows that these Brownian processes are indeed observed in unbounded motion tasks e.g., rotating a crank. We further predict that such growing variance would still be present, but bounded, in tasks requiring a constant posture e.g., maintaining a static hand position or quietly standing. This hypothesis was also confirmed by experimental observations. A series of descriptive models are investigated to justify the observed behavior. Interestingly, one of the models capable of accounting for all the experimental results must feature forward-path velocity commands corrupted by stationary noise. The results of this work provide behavioral support for the hypothesis that humans plan the motion components of their actions in terms of velocity.

Machine learning-based detection of acute psychosocial stress from body posture and movements

Investigating acute stress responses is crucial to understanding the underlying mechanisms of stress. Current stress assessment methods include self-reports that can be biased and biomarkers that are often based on complex laboratory procedures. A promising additional modality for stress assessment might be the observation of body movements, which are affected by negative emotions and threatening situations. In this paper, we investigated the relationship between acute psychosocial stress induction and body posture and movements. We collected motion data from N = 59 individuals over two studies (Pilot Study: N = 20, Main Study: N = 39) using inertial measurement unit (IMU)-based motion capture suits. In both studies, individuals underwent the Trier Social Stress Test (TSST) and a stress-free control condition (friendly-TSST; f-TSST) in randomized order. Our results show that acute stress induction leads to a reproducible freezing behavior, characterized by less overall motion as well as more and longer periods of no movement. Based on these data, we trained machine learning pipelines to detect acute stress solely from movement information, achieving an accuracy of75.0 ± 17.7 % (Pilot Study) and73.4 ± 7.7 % (Main Study). This, for the first time, suggests that body posture and movements can be used to detect whether individuals are exposed to acute psychosocial stress. While more studies are needed to further validate our approach, we are convinced that motion information can be a valuable extension to the existing biomarkers and can help to obtain a more holistic picture of the human stress response. Our work is the first to systematically explore the use of full-body body posture and movement to gain novel insights into the human stress response and its effects on the body and mind.

Analysis of the obstetrician's posture and movements during a simulated forceps delivery

BACKGROUND

The objective of this study was to identify and qualify, by means of a three-dimensional kinematic analysis, the postures and movements of obstetricians during a simulated forceps birth, and then to study the association of the obstetricians' experience with the technique adopted.

METHOD

Fifty-seven volunteer obstetricians, 20 from the Limoges and 37 from the Poitiers University hospitals, were included in this multi-centric study. They were classified into 3 groups: beginners, intermediates, and experts, beginners having performed fewer than 10 forceps deliveries in real conditions, intermediates between 10 and 100, and experts more than 100. The posture and movements of the obstetricians were recorded between December 2020 and March 2021 using an optoelectronic motion capture system during simulated forceps births. Joint angles qualifying these postures and movements were analysed between the three phases of the foetal traction. These phases were defined by the passage of a virtual point associated with the forceps blade through two anatomical planes: the mid-pelvis and the pelvic outlet. Then, a consolidated ascending hierarchical classification (AHC) was applied to these data in order to objectify the existence of groups of similar behaviours.

RESULTS

The AHC distinguished four different postures adopted when crossing the first plane and three different traction techniques. 48% of the beginners adopted one of the two raised posture, 22% being raised without trunk flexion and 26% raised with trunk flexion. Conversely, 58% of the experts positioned themselves in a "chevalier servant" posture (going down on one knee) and 25% in a "squatting" posture before initiating traction. The results also show that the joint movement amplitude tends to reduce with the level of expertise.

CONCLUSION

Forceps delivery was performed in different ways, with the experienced obstetricians favouring postures that enabled observation at the level of the maternal perineum and techniques reducing movement amplitude. The first perspective of this work is to relate these different techniques to the traction force generated. The results of these studies have the potential to contribute to the training of obstetricians in forceps delivery, and to improve the safety of women and newborns.

An enhanced real-time human pose estimation method based on modified YOLOv8 framework

The objective of human pose estimation (HPE) derived from deep learning aims to accurately estimate and predict the human body posture in images or videos via the utilization of deep neural networks. However, the accuracy of real-time HPE tasks is still to be improved due to factors such as partial occlusion of body parts and limited receptive field of the model. To alleviate the accuracy loss caused by these issues, this paper proposes a real-time HPE model called CCAM - Person based on the YOLOv8 framework. Specifically, we have improved the backbone and neck of the YOLOv8x-pose real-time HPE model to alleviate the feature loss and receptive field constraints. Secondly, we introduce the context coordinate attention module (CCAM) to augment the model's focus on salient features, reduce background noise interference, alleviate key point regression failure caused by limb occlusion, and improve the accuracy of pose estimation. Our approach attains competitive results on multiple metrics of two open-source datasets, MS COCO 2017 and CrowdPose. Compared with the baseline model YOLOv8x-pose, CCAM-Person improves the average precision by 2.8% and 3.5% on the two datasets, respectively.

Electrocardiographic and Autonomic Nervous System Changes after Changes in the Posture of Children and Adolescents with Duchenne Muscular Dystrophy

BACKGROUND

Duchenne Muscular Dystrophy (DMD) is a rare inherited neuromuscular disease. At first, cardiac involvement may be asymptomatic. Therefore, assessing patients using non-invasive methods can help detect any changes.

OBJECTIVES

Analyze the electrocardiogram (ECG) test and heart rate variability (HRV) of the DMD group and compare the information with that of the age-matched control group.

METHODS

A prospective study with 27 male patients with DMD (11.9 years old), who underwent clinical evaluation, ECG, echocardiogram, and Holter monitoring. ECG (200% increase) was assessed by two independent observers. HRV was measured over time (24 h) and in the frequency domain, in the supine and sitting positions. The healthy group consisted of nine patients (11.0 years old). A value of p < 0.05 was considered statistically significant.

RESULTS

The mean ejection fraction (EF) was 60% (34 to 71%). The Kappa coefficient for ECG measurements ranged from 0.64 to 1.00. An increase in the R/S ratio in V1 was observed in 25.9% of the subjects, pathological Q wave in 29.6%, and fragmented QRS in 22.2% in inferior/high lateral regions, with a negative correlation with EF (p = 0.006). There was low HRV, without the influence of any variable, including treatment. With the change in position, there was an increase in HR (p = 0.004), but there was no change in HRV. The LF/HF ratio was 2.7 in the DMD group and 0.7 in the control group (p = 0.002).

CONCLUSIONS

In DMD subjects, prominent R waves in V1 and changes in the inferior/high lateral regions occurred in almost 30% of the cases. Lower vagal tone was observed without the influence of the variables age, ejection fraction, QT dispersion, and treatment. Despite the increase in HR, there was no adequate HRV response to the change in position.

The control of the arm's equilibrium position

To generate a force, the brain activates muscles that act like springs to pull the arm toward a new equilibrium position. The equilibrium position (EP) is central to our understanding of the biological control of viscoelastic muscles. Although there is evidence of the EP during the control of limb posture, EPs have not been directly identified when the limb exerts a force against the environment. Here, we asked participants to apply a constant force in one of eight directions against a point-like constraint. This constraint was released abruptly to observe the final position to which the arm converged. Importantly, the same force magnitude was maintained while changing the arm's stiffness by modulating the strength of the hand's power grasp. The final position moved further away from the constraint as the arm became less stiff and was inversely proportional to the arm's stiffness, thereby confirming that the final position was the arm's EP. These results demonstrate how the EP changes with the arm's stiffness to produce a desired force in different directions.NEW & NOTEWORTHY According to numerous theories, the brain controls posture and movement by activating muscles that attract the limb toward a so-called equilibrium position, but the universality of this mechanism has not been shown for different motor behaviors. Here, we show that even when pushing or pulling against the environment, the brain achieves the desired force through an equilibrium position that lies beyond the physical constraint.

The influence of hand posture on tactile processing: Evidence from a 7T functional magnetic resonance imaging study

Although behavioral evidence has shown that postural changes influence the ability to localize or detect tactile stimuli, little is known regarding the brain areas that modulate these effects. This 7T functional magnetic resonance imaging (fMRI) study explores the effects of touch of the hand as a function of hand location (right or left side of the body) and hand configuration (open or closed). We predicted that changes in hand configuration would be represented in contralateral primary somatosensory cortex (S1) and the anterior intraparietal area (aIPS), whereas change in position of the hand would be associated with alterations in activation in the superior parietal lobule. Multivoxel pattern analysis and a region of interest approach partially supported our predictions. Decoding accuracy for hand location was above chance level in superior parietal lobule (SPL) and in the anterior intraparietal (aIPS) area; above chance classification of hand configuration was observed in SPL and S1. This evidence confirmed the role of the parietal cortex in postural effects on touch and the possible role of S1 in coding the body form representation of the hand.

Dose-Response Effect of an Inertia Flywheel Postactivation Performance Enhancement Protocol on Countermovement Jump Performance

The purpose of this study was to investigate the dose-response effect of a high-load, 6-repetition, maximum effort inertial flywheel (IFw) squat postactivation performance enhancement (PAPE) protocol on countermovement jump (CMJ) performance metrics. Thirteen subjects completed 5 squat testing sessions: 1 session to determine back-squat 6-repetition maximum, 1 session to determine 6-repetition maximum IFw load, and 3 sessions to investigate the dose-response effect of an IFw PAPE protocol set at the load determined in the second session. In the IFw PAPE sessions, subjects completed either 1, 2, or 3 sets of IFw squats, then performed 5 CMJs over 12 minutes (1, 3, 6, 9, and 12 min post-IFw). All CMJ tests were conducted on a force platform where CMJ performance outcomes and impulse variables were calculated. There was no main time or volume effect for jump height, contact time, reactive strength index, peak force, or any of the impulse variables. A main time effect was identified for flight time (P = .006, effect size = 0.24) and peak power (P = .001, effect size = 0.28). The lack of change in jump height may indicate that too much fatigue was generated following this near-maximal IFw squat protocol, thereby reducing the PAPE effect.

Stand up to better pay attention, sit down to better subtract: a new perspective on the advantage of cognitive-motor interactions

The Stroop task and subtraction rely on the different cognitive processes and cerebral regions, but both these cognitive functions interact with posture. The study of cognitive-motor interactions falls under the concept of sharing resources, implying that resources for processing are limited. Researchers try to understand this interaction by constructing dual task (DT) paradigms. None have investigated the Stroop and subtraction tasks in three inherently simple postures in two groups of young adults. This study aimed to test whether a given posture benefits a given cognitive function when cognitive and postural tasks are not overly demanding and are underpinned by common cerebral structures. This study presents the results of 60 healthy young adults performing a subtraction task in three postures (sitting, standing, and walking) and 57 healthy young adults performing the Stroop task in the same three postures. Our results showed that performance at the Stroop task, in terms of number of correct answers and interference, are better while standing or even walking compared to sitting while subtraction is better sitting compared to standing and walking. Moreover, static postural parameters did not vary when in DT compared to single task. This means that there was no additional cost on posture when achieving the cognitive activity simultaneously. The absence of impact of the DT on postural parameters in static postures and the changes in the gait pace when walking suggest that cognitive tasks can be achieved in various postures, without being too costly on posture.

The effect of using birth ball and squatting position during labor on pain, duration, and satisfaction: A randomized controlled trial

AIM

The aim of this study is to assess the effect of using a birth ball and squatting position during labor on labor pain, duration of labor, and satisfaction.

METHODS

This study is a randomized controlled experimental trial. It was conducted in the delivery unit of Başakşehir Çam and Sakura City Hospital. The study sample consisted of a total of 159 women, 53 in the birth ball application room, 53 in the squatting position group, and 53 in the control group. The "Information Form," "Visual Analog Scale," "Partograph," and "Maternal Satisfaction Assessment at Delivery Scale-Normal Birth" were used in the data collection. Data were analyzed using analysis of variance, Pearson's Chi-square test, Pillai's trace test.

RESULTS

The present study revealed that the pain perception level was lower in the birth ball and squatting position groups compared to the control group, and there was a statistically significant difference between them (p < .05). The duration of the first and second stages of labor and the total duration of labor decreased in the birth ball and squatting position groups (p < .05). The difference was statistically significant in comparing the level of satisfaction (p < .05). It was found that the highest satisfaction was in the birth ball group.

CONCLUSION

Using a birth ball and squatting position during labor are effective methods of reducing labor pain, shortening the duration of labor, and increasing the level of satisfaction. There is a need for more studies on the effects of the birth ball and squatting position.

CLINICALTRIALS

gov Identifier: NCT05360823.

Postactivation performance enhancement in the vertical jump using loads above or below the optimum-power load for a jump squat

BACKGROUND

Postactivation performance enhancement (PAPE) is an acute response of increased muscle performance following a conditioning activity (CA), generally prescribed based on the percentage of a one-repetition maximum. However, it is unknown how the PAPE response is affected when the CA is performed near the optimum power zone. The purpose of this study was to examine PAPE using loads that were 20% above or below the optimum-power load (OPL).

METHODS

Fifteen recreationally trained subjects, with at least one-year resistance training experience participated in this study. First, the OPL for the JS was determined. Then, subjects performed two protocols in a counterbalanced order: 20% above (+20%OPL) or below (-20%OPL). To examine PAPE on performance, the vertical jump was performed prior to and seven times following each jump squat protocol, with a 2-min rest interval between trials.

RESULTS

The two-way ANOVA revealed main effects for condition (F=4.978; P<0.001) for jump height and jump power (F=2.589; P=0.017), but post-hoc comparisons did not show differences. Between baseline and the best trial following each jump squat protocol, two-way ANOVA did not reveal main effects (F=3.048; P=0.103) or interactions (F=0.304; P=0.590). Paired t-tests did not show significant differences between conditions for relative changes in jump height (P=0.543) or jump power (P=0.233).

CONCLUSIONS

This study revealed similar results between 20% above or below the OPL on subsequent vertical jump performance.

A field approach to observing changes in behavioural welfare indicators over 2 years in stabled horses

In stabled horses, several behaviours are considered to be important indicators of the state of welfare at the individual level: stereotypies, aggressive behaviours towards humans and the "withdrawn", alert, sternal, lateral and observation postures. Until now, these behaviours have been extensively studied in relation to different horse management practices. However, little is known about their changes or consistency over time. This study aimed to investigate differences in the expression of these behaviours assessed on 44 stabled horses during an initial 3-month period and then again on the same individuals 2 years later. Out of the six behaviours studied, two showed significant differences between the 2 years with medium effect sizes: the levels of aggressiveness towards humans increased (Wilcoxon signed-rank test: V = 65, P = 0.005) and those of recumbent rest during the day decreased (V = 416, P < 0.001) over time. The results also suggested limited evidence of major changes over time in the expression of stereotypies, the "withdrawn", alert and observation postures. However, the principal component analyses carried out on all the behaviours showed that alert and observation postures may slightly decrease over time for some individuals. Regarding stereotypies and the "withdrawn" posture, the results mainly suggested a change at the individual level in the expression of these behaviours over time. This study provided new insights into the dynamic nature of several behaviours when the horses' living conditions are not fundamentally altered and raised hypotheses about the state of welfare of stabled individuals over a 2-year period.

Position- and posture-dependent vascular imaging-a scoping review

OBJECTIVES

Position- and posture-dependent deformation of the vascular system is a relatively unexplored field. The goal of this scoping review was to create an overview of existing vascular imaging modalities in different body positions and postures and address the subsequent changes in vascular anatomy.

METHODS

Scopus, Medline, and Cochrane were searched for literature published between January 1, 2000, and June 30, 2022, incorporating the following categories: image modality, anatomy, orientation, and outcomes.

RESULTS

Out of 2446 screened articles, we included 108. The majority of papers used ultrasound (US, n = 74) in different body positions and postures with diameter and cross-sectional area (CSA) as outcome measures. Magnetic resonance imaging (n = 22) and computed tomography (n = 8) were less frequently used but allowed for investigation of other geometrical measures such as vessel curvature and length. The venous system proved more sensitive to postural changes than the arterial system, which was seen as increasing diameters of veins below the level of the heart when going from supine to prone to standing positions, and vice versa.

CONCLUSIONS

The influence of body positions and postures on vasculature was predominantly explored with US for vessel diameter and CSA. Posture-induced deformation and additional geometrical features that may be of interest for the (endovascular) treatment of vascular pathologies have been limitedly reported, such as length and curvature of an atherosclerotic popliteal artery during bending of the knee after stent placement. The most important clinical implications of positional changes are found in diagnosis, surgical planning, and follow-up after stent placement.

CLINICAL RELEVANCE STATEMENT

This scoping review presents the current state and opportunities of position- and posture-dependent imaging of vascular structures using various imaging modalities that are relevant in the fields of clinical diagnosis, surgical planning, and follow-up after stent placement.

KEY POINTS

• The influence of body positions and postures on the vasculature was predominantly investigated with US for vessel diameter and cross-sectional area. • Research into geometrical deformation, such as vessel length and curvature adaptation, that may be of interest for the (endovascular) treatment of vascular pathologies is limited in different positions and postures. • The most important clinical implications of postural changes are found in diagnosis, surgical planning, and follow-up after stent placement.

Postural control and trunk stability on sway parameters in adults with and without chronic low back pain

BACKGROUND

Postural sway changes often reflect functional impairments in adults with chronic low back pain (LBP). However, there is a gap in understanding how these individuals adapt their postural strategies to maintain stability.

PURPOSE

This study investigated postural sway distance and velocity, utilizing the center of pressure (COP) and center of gravity (COG), between adults with and without LBP during repeated unilateral standing trials.

METHODS

Twenty-six subjects with LBP and 39 control subjects participated in the study. Postural sway ranges, COP/COG sways, and sway velocities (computed by dividing path length by time in anteroposterior (AP) and mediolateral (ML) directions over 10 s) were analyzed across three unilateral standing trials.

RESULTS

A significant group interaction in sway range difference was observed following repeated trials (F = 5.90, p = 0.02). For COG sway range, significant group interactions were demonstrated in both directions (F = 4.28, p = 0.04) and repeated trials (F = 5.79, p = 0.02). The LBP group demonstrated reduced ML sway velocities in the first (5.21 ± 2.43 for the control group, 4.16 ± 2.33 for the LBP group; t = 1.72, p = 0.04) and second (4.87 ± 2.62 for the control group, 3.79 ± 2.22 for the LBP group; t = 1.73, p = 0.04) trials.

CONCLUSION

The LBP group demonstrated decreased ML sway velocities to enhance trunk stability in the initial two trials. The COG results emphasized the potential use of trunk strategies in augmenting postural stability and optimizing neuromuscular control during unilateral standing.

Investigating the effects of postural habits and awareness on early adolescent's internet addiction levels

OBJECTIVES

Early adolescence is a period of growth and development determined by the onset of puberty, during which important changes in psychological development and social roles occur. Excessive use of the internet, especially in adolescents in this period, causes health problems such as postural disorders, vision problems, sedentary life, and unbalanced nutrition. When the studies are analyzed, it is observed that postural disorders are observed in children and adolescents. This study was planned to investigate the effect of postural habits and awareness on the level of internet addiction in early adolescents.

METHODS

Physical characteristics of the participants (age, height, weight, gender, body mass index) were recorded. Duration and purpose of internet use and internet addiction were determined with the Young Internet Addiction Test-Short Form, body composition sensitivity level with the Body Awareness Questionnaire, and postural awareness with the Postural Habit and Awareness Scale.

RESULTS

There was a significant positive correlation between internet addiction and duration of internet use (r=0.466) (p=0.000). In addition, there was no relationship between internet usage time and body awareness (r=-0.117) (p=0.084) and postural awareness and habit (r=-0.017) (p=0.798). When internet addiction was compared with body awareness, a significant relationship was found in the opposite direction (r=-0.145) (p=0.031). When internet addiction was compared with postural awareness and habit, a positive relationship was found (r=0.190) (p=0.005).

CONCLUSIONS

Our study showed that internet addiction negatively affects body awareness, and does not affect postural habits, but positively affects postural awareness.

Comments on the pelvic girdle anatomy of Lagerpeton chanarensis Romer, 1971 (Archosauria) and its implications on the posture and gait of early pterosauromorphs

Lagerpeton chanarensis is an early avemetatarsalian from the lower Carnian (lowermost Upper Triassic) levels of the Chañares Formation, La Rioja Province, Argentina. Lagerpeton and its kin were traditionally interpreted as dinosaur precursors of cursorial habits, with a bipedal posture and parasagittal gait. Some authors also speculated saltatorial capabilities for this genus. Recent analyses indicate that lagerpetids are early-diverging pterosauromorphs, a hypothesis that invites a review of most aspects of their anatomy and function. A revision of available specimens and additional preparation of previously known individuals indicate that Lagerpeton lacked a parasagittal gait and was probably a sprawling archosaur. This latter inference is based on the femoral head articulation with the acetabulum. The acetabular rim has a strongly laterally projected posteroventral antitrochanteric corner, which results in a position of the legs that recalls that of sprawling living reptiles, such as lizards, and departs from the parasagittally positioned limbs of dinosaurs. This may indicate that early pterosauromorphs had a sprawling posture of their hindlegs, casting doubts on the significance of bipedal posture and parasagittal gait for the radiation of early ornithodirans, given that both traits have been regarded as key features that triggered the ecological and evolutionary success of the clade. Our results bolster recent claims of a high ecomorphological diversity among early avemetatarsalians.

Evaluating Pelvic Tilt Using the Pelvic Antero-Posterior Projection Images: A Systematic Review

BACKGROUND

Pelvic tilt (PT) is a routinely evaluated parameter in hip and spine surgeries, and is usually measured on a sagittal pelvic radiograph. This may not always be feasible due to limitations such as landmark visibility, pelvic anomaly, and hardware presence. Tremendous efforts have been dedicated to using pelvic antero-posterior (AP) radiographs for assessing sagittal PT. Thus, this systematic review aimed to collect these methods and evaluate their performances.

METHODS

Two independent reviewers searched the PubMed, Ovid, Cochrane, and Web of Science databases in June 2023 with backward reference trailing (Google Scholar archive). There were 30 studies recruited. Risk of bias was assessed using the prediction model risk of bias assessment tool. The relevant data were tabulated in a standardized form for evaluating either the absolute PT or relative PT. Disagreement was resolved by discussing with the senior author.

RESULTS

There were 19 parameters from pelvic AP projection images involved, with 4 studies which used artificial intelligence, eyeball, or statistical shape method not involving a specific parameter. In comparing the PT values from pelvic sagittal images with those extrapolated from antero-posterior projection images, the highest correlation coefficient was found to be 0.91. The mean absolute difference (error) was 2.6°, with a maximum error reaching 10.9°. Most studies supported the feasibility of using AP parameters to calculate changes in PT.

CONCLUSIONS

No individual AP parameter was found to precisely estimate absolute PT. However, relative PT can be derived by evaluating serial AP radiographs of a patient in varying postures, employing any AP parameters.

Cross-cultural adaptation and reliability of the Foot Posture Index (FPI-6) - French version

PURPOSE

The 6-item Foot Posture Index (FPI-6) is a reliable tool for the evaluation of foot deformities. Our aim was to translate and cross-culturally validate the FPI-6 for use in French-speaking countries and to determine the intra-rater and inter-rater reliability of the French version.

METHODS

Cross-cultural adaptation was performed according to guidelines. Two clinicians assessed the FPI-6 in 52 asymptomatic individuals. We evaluated intra- and inter-rater reliability with the intraclass correlation coefficients (ICC), correlations (p-value < 0.05) and Bland-Altman plots. Standard error of measurement (SEM) and minimum detectable change (MDC95) were determined.

RESULTS

For the cross-cultural adaptation, we modified several items of the FPI-6 user guide and added footnotes to ensure correct interpretation. ICC of the total FPI-6 scores were 0.94 to 0.96 for the intra- and inter-rater reliability for dominant and non-dominant lower limb. Correlations were significant (p < 0.001); r 0.88 to 0.92. Total score SEM was 0.68 to 0.78 and MDC95 was 1.58 to 1.82.

CONCLUSIONS

Intra- and inter-rater reliability of this French version of the FPI-6 was excellent for the total score and good to excellent for each item. The French FPI-6 can be used in French-speaking countries. The identification of SEM and MDC scores is useful for clinical interpretation.

Variations in pelvic tilt during day-to-day activities after total hip arthroplasty measured with an ultrasound system

INTRODUCTION

The pelvis plays a major role in the orientation of total hip arthroplasty (THA) implants and consequently, on the postoperative stability of the new hip joint. The relationship between the spine and pelvis affects the functional orientation of the acetabular cup, although this relationship differs between individuals and the positions encountered in everyday life. We believe this should be factored in when planning the THA procedure. This led us to conduct an in vivo ultrasound study to document the values of pelvic tilt in standing, sitting and lying positions in patients who have advanced hip osteoarthritis, before and after they undergo THA.

HYPOTHESIS

The pelvic tilt when standing, sitting and lying supine does not change significantly after THA.

MATERIALS AND METHODS

The pelvic tilt, defined as the angle between the anterior pelvic plane and a vertical line was measured using an ultrasound device in 30 patients before the THA procedure and again 6 months later in standing, sitting and lying positions. The measurements were done during an office visit with the patient on an examination table for the lying position, on a chair for the sitting position and with the heels and occiput against the wall for the standing position.

RESULTS

The preoperative and 6-month postoperative pelvic tilt were -5.6̊±10.4̊ [-30.6̊; 11.7̊] and -5.8̊±7.9̊ [-20.6̊; 10.4̊] (p=0.4129) when standing, -44.5̊±6.10 [-53.8̊; -23.9̊] and -43.5̊±6.9̊ [-54.4̊; -17.3̊] (p=0.5760) when sitting, -88.3̊±5.1̊ [-99.3̊; -78.7̊] and -87.9̊±5.9̊ [-97.6̊; -72.4̊] (p=0.6106) when lying supine, respectively. There was no significant difference in the pelvic tilt before and 6 months after THA procedure. Variations of±5̊; ±5-10̊; ±10-15̊ and 15-20̊ were found in 72% (18); 20% (5); 4% (1) and 4% (1) of patients when lying supine, 56% (14); 36% (9); 8% (2); 0% (0) of patients when standing and 76% (19); 24% (6); 0% (0); 0% (0) when sitting. The mean variation for each patient between the preoperative and 6 months postoperative measurement was 4.8±3.4̊ [0.8̊; 10.4̊] (p=0.4129), 3.5±2.3̊ [0.2̊; 9.1̊] (p=0.5760), and 4.6̊±3.2̊ [1.2̊; 15.4̊] (p=0.6106) for the standing, sitting and lying positions respectively.

CONCLUSION

The pelvic tilt does not significantly change 6 months after THA. Taking into account the various positions used in everyday life may help to optimize the implant position. We have described the use of an affordable, accurate and non-irradiating device that provides fast and easy measurements of pelvic tilt in various positions.

LEVEL OF EVIDENCE

IV.

Changes in Spinopelvic Parameters Between Standing and Sitting Postures: A Systematic Review and Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To report the ratio-of-differences between standing and sitting. To understand how sex and age influence these differences.

SUMMARY OF BACKGROUND DATA

Currently, spinal deformity surgery aims to realign the sagittal profile of the spine with-reference-to the standing posture resulting in overcorrection. New studies report significant disparities between standing and sitting spinal alignment.

METHODS

A comprehensive search and review of the published literature was performed on 4 platforms in accordance with the PRISMA 2009 checklist by 2 authors independently.

RESULTS

From 753 abstracts extracted from the databases, 38 papers involving 5423 patients were identified. sagittal vertical axis was more positive in sitting, with a pooled mean difference of 29.5 mm (95% CI: 17.9-41.0). Pelvic tilt (PT) was larger in sitting, with a pooled mean difference of 16.7 degrees (95% CI: 12.5-20.9), and a pooled odds ratio of 1.2(95% CI:1.1-1.3. P =0.001). Sacral Slope (SS) was smaller and lumbar lordosis (LL) was less lordotic in sitting, with a pooled mean difference of 15.0 degrees (95% CI: 11.918.1) and 21.1 degrees (95% CI:14.5-27.8), respectively, and a pooled odds ratio of 0.7 (95% CI: 0.6-0.8. P <0.001) and 0.7 (95% CI:0.6-0.7, P <0.001), respectively. Pelvic incidence and thoracic kyphosis was similar in sitting. Subgroup meta-analysis comparing odd ratio of standing to sitting showed: Among younger patients (age younger than 50), the PT and LL pooled odds-ratios were 1.4 and 0.7, respectively. Among older patients (age older than or equal to 50), the PT and LL pooled odds-ratios were 1.1 and 0.8, respectively. Among female patients, the SS pooled odds ratio was 0.6. Among male patients, the SS pooled odds ratio was 0.7.

CONCLUSION

When comparing sitting to standing, it gives a more positive sagittal vertical axis, a smaller SS and LL, and a larger PT. pelvic incidence and thoracic kyphosis remained similar. Younger and female patients have pronounced differences in SS, PT, and LL, suggesting the existence of age and sex variations, and its role to be considered when planning for spinal realignment surgeries. Clinical outcome studies are required to ascertain the impact of these findings.

An in Vivo, Three-Dimensional (3D), Functional Centers of Rotation of the Healthy Cervical Spine

OBJECTIVE

This study examined cervical center of rotation (COR) positions in 7 postures using validated cone beam computed tomography (CBCT) combined with 3D-3D registration in healthy volunteers.

METHODS

CBCT scans were performed on 20 healthy volunteers in 7 functional positions, constructing a three-dimensional (3D) model. Images were registered to the neutral position using 3D-3D registration, allowing analysis of kinematic differences and rotational axes. COR measurements were obtained for each segment (C2/3 to C6/7) in each posture.

RESULTS

The CORs of C2/3 to C6/7 were predominantly posterior (-5.3 ± 3.8 ∼ -0.6 ± 1.2 mm) and superior (16.5 ± 6.0 ∼ 23.6 ± 3.2 mm) to the intervertebral disc's geometric center (GC) in flexion and extension. However, the C4/5 segment's COR was anterior to the GC (2.0 ± 9.8 mm) during flexion and close to it in the right-left direction. During left-right twisting, the CORs of C2/3-C6/7 were posterior (-21.8 ± 10.5 ∼-0.9 ± 0.8 mm) and superior (3.1 ± 7.5 ∼23.2 ± 3.6 mm) to the GCs in anterior-posterior and superior-inferior directions, without consistent right-left directionality. During left-right bending, each segment's COR was predominantly posterior (-25.2 ± 13.1 ∼-6.5 ± 9.9 mm) and superior (0.3 ± 12.5 ∼12.1 ± 5.1 mm) to the GC in anterior-posterior and superior-inferior directions, except for the C2/3 segment, located inferiorly (-5.9 ± 4.1 mm) in left bending. The right-left COR position varied across segments.

CONCLUSIONS

Our findings reveal segment-specific and posture-dependent COR variations. Notably, the CORs of C3/4, C4/5, and C5/6 consistently align near the intervertebral disc's GC at different postures, supporting their suitability for total disc replacement surgery within the C3/4 to C5/6 segments.

Measurement of Sedentary Behavior-The Outcomes of the Angle for Posture Estimation (APE) Method

Hip-worn accelerometers are commonly used to assess habitual physical activity, but their accuracy in precisely measuring sedentary behavior (SB) is generally considered low. The angle for postural estimation (APE) method has shown promising accuracy in SB measurement. This method relies on the constant nature of Earth's gravity and the assumption that walking posture is typically upright. This study investigated how cardiorespiratory fitness (CRF) and body mass index (BMI) are related to APE output. A total of 3475 participants with adequate accelerometer wear time were categorized into three groups according to CRF or BMI. Participants in low CRF and high BMI groups spent more time in reclining and lying postures (APE ≥ 30°) and less time in sitting and standing postures (APE < 30°) than the other groups. Furthermore, the strongest partial Spearman correlation with CRF (r = 0.284) and BMI (r = -0.320) was observed for APE values typical for standing. The findings underscore the utility of the APE method in studying associations between SB and health outcomes. Importantly, this study emphasizes the necessity of reserving the term "sedentary behavior" for studies wherein the classification of SB is based on both intensity and posture.

Plantar load distribution with centers of gravity balance and rearfoot posture in daily lives of Taiwanese college elite table tennis players: a cross-sectional study

Background

Table tennis is an asymmetric sport involving the powerful forward swing of the upper limbs depends on the solid support of the lower limbs. The foot drive really affects the weight balance and stroke accuracy even though the distance and momentum of the lower limb displacement are limited within a limited range. Given that previous research on table tennis has typically focused on the footwork and stroke performance of professional players, the study aimed to investigate the daily static and dynamic plantar load distribution as well as the centers of gravity balance and rearfoot posture among Taiwanese college elite table tennis players.

Methods

This is a cross-sectional study of 70 elite male table tennis players (age: 20.0 ± 0.9 years; height: 173.4 ± 5.1 cm, weight: 67.6 ± 5.3 kg, experience: 10.0 ± 1.6 years) and 77 amateur table tennis players of the same gender (age: 20.1 ± 0.8 years, height: 167.4 ± 4.4 cm, weight: 64.3 ± 4.0 kg, experience: 4.4 ± 1.2 years) from Taiwanese universities. The JC Mat optical plantar pressure analyzer was applied to determine the plantar load distribution along with arch index (AI) and centers of gravity balance. Assessment of rearfoot postural alignment was mainly used to contrast the performance of the centers of gravity balance.

Results

The static arch indices of both feet in the elite group were symmetrical and considered normal arches (AI: 0.22 ± 0.07) during their non-training and non-competition daily lives. Their static plantar loads were symmetrically concentrated on the bipedal lateral metatarsals (P < 0.05) as well as shifted to the medial and lateral heels (P < 0.05) and the lateral metatarsals (P < 0.05) during the walking midstance phase. Additionally, the plantar loads were mainly applied to the bipedal medial (P < 0.01) and lateral heels (P < 0.05) during the transitional changes between both states. Elite athletes had symmetrical and evenly distributed centers of gravity on both feet (left: 50.03 ± 4.47%; right: 49.97 ± 4.47%) when standing statically, along with symmetrical rearfoot angles and neutral position of the subtalar joint (left: 2.73 ± 2.30°; right: 2.70 ± 2.32°) even though they were statistically lower than those of the amateur athletes (P < 0.05).

Conclusions

The daily static and dynamic foot patterns of Taiwanese college elite table tennis players were characterized by plantar load distribution on the lateral metatarsals and the entire calcaneus along with balanced centers of gravity and normal rearfoot posture. This foot and posture layout outlines the excellent athletic performance of the foot and ankle in professional athletes. Portions of this text were previously published as part of a preprint (https://doi.org/10.21203/rs.3.rs-2993403/v1).

sEMG-Based Robust Recognition of Grasping Postures with a Machine Learning Approach for Low-Cost Hand Control

The design and control of artificial hands remains a challenge in engineering. Popular prostheses are bio-mechanically simple with restricted manipulation capabilities, as advanced devices are pricy or abandoned due to their difficult communication with the hand. For social robots, the interpretation of human intention is key for their integration in daily life. This can be achieved with machine learning (ML) algorithms, which are barely used for grasping posture recognition. This work proposes an ML approach to recognize nine hand postures, representing 90% of the activities of daily living in real time using an sEMG human-robot interface (HRI). Data from 20 subjects wearing a Myo armband (8 sEMG signals) were gathered from the NinaPro DS5 and from experimental tests with the YCB Object Set, and they were used jointly in the development of a simple multi-layer perceptron in MATLAB, with a global percentage success of 73% using only two features. GPU-based implementations were run to select the best architecture, with generalization capabilities, robustness-versus-electrode shift, low memory expense, and real-time performance. This architecture enables the implementation of grasping posture recognition in low-cost devices, aimed at the development of affordable functional prostheses and HRI for social robots.

Deep Learning Model to Evaluate Sensorimotor System Ability in Patients With Dizziness for Postural Control

Balanced posture without dizziness is achieved via harmonious coordination of visual, vestibular, and somatosensory systems. Specific frequency bands of center of pressure (COP) signals during quiet standing are closely related to the sensory inputs of the sensorimotor system. In this study, we proposed a deep learning-based novel protocol using the COP signal frequencies to estimate the equilibrium score (ES), a sensory system contribution. Sensory organization test was performed with normal controls (n=125), patients with Meniere's disease (n=72) and vestibular neuritis (n=105). The COP signals preprocessed via filtering, detrending and augmenting during quiet standing were converted to frequency domains utilizing Short-time Fourier Transform. Four different types of CNN backbone including GoogleNet, ResNet-18, SqueezeNet, and VGG16 were trained and tested using the frequency transformed data of COP and the ES under conditions #2 to #6. Additionally, the 100 original output classes (1 to 100 ESs) were encoded into 50, 20, 10 and 5 sub-classes to improve the performance of the prediction model. Absolute difference between the measured and predicted ES was about 1.7 (ResNet-18 with encoding of 20 sub-classes). The average error of each sensory analysis calculated using the measured ES and predicted ES was approximately 1.0%. The results suggest that the sensory system contribution of patients with dizziness can be quantitatively assessed using only the COP signal from a single test of standing posture. This study has potential to reduce balance testing time (spent on six conditions with three trials each in sensory organization test) and the size of computerized dynamic posturography (movable visual surround and force plate), and helps achieve the widespread application of the balance assessment.

Concurrent Supra-Postural Auditory-Hand Coordination Task Affects Postural Control: Using Sonification to Explore Environmental Unpredictability in Factors Affecting Fall Risk

Clinical screening tests for balance and mobility often fall short of predicting fall risk. Cognitive distractors and unpredictable external stimuli, common in busy natural environments, contribute to this risk, especially in older adults. Less is known about the effects of upper sensory-motor coordination, such as coordinating one's hand with an external stimulus. We combined movement sonification and affordable inertial motion sensors to develop a task for the precise measurement and manipulation of full-body interaction with stimuli in the environment. In a double-task design, we studied how a supra-postural activity affected quiet stance. The supra-postural task consisted of rhythmic synchronization with a repetitive auditory stimulus. The stimulus was attentionally demanding because it was being modulated continuously. The participant's hand movement was sonified in real time, and their goal was to synchronize their hand movement with the stimulus. In the unpredictable condition, the tempo changed at random points in the trial. A separate sensor recorded postural fluctuations. Young healthy adults were compared to older adult (OA) participants without known risk of falling. The results supported the hypothesis that supra-postural coordination would entrain postural control. The effect was stronger in OAs, supporting the idea that diminished reserve capacities reduce the ability to isolate postural control from sensory-motor and cognitive activity.

Gait pattern can alter aesthetic visual impression from a third-person perspective

Beauty is related to our lives in various ways and examining it from an interdisciplinary approach is essential. People are very concerned with their appearance. A widely accepted beauty ideal is that the thinner an individual is, the more beautiful they are. However, the effect of continuous motion on body form aesthetics is unclear. Additionally, an upright pelvic posture in the sagittal plane during walking seems to affect the aesthetic judgments of female appearance. We directly analyzed the influence of body form and walking pattern on aesthetic visual impressions from a third-person perspective with a two-way analysis of variance. Captured motion data for three conditions-upright pelvis, normal pelvis, and posteriorly tilted pelvic posture-were applied to each of three mannequins, representing thin, standard, and obese body forms. When participants watched stimulus videos of the mannequins walking with various postures, a significantly higher score for aesthetic visual impression was noted for an upright pelvic posture than for a posteriorly tilted pelvic posture, irrespective of body form (F(2, 119) = 79.89, p < 0.001, η2 = 0.54). These findings show that the third-person perspective of beauty can be improved even without being thin by walking with an upright pelvic posture.

Extinct and extant termites reveal the fidelity of behavior fossilization in amber

Fossils encompassing multiple individuals provide rare direct evidence of behavioral interactions among extinct organisms. However, the fossilization process can alter the spatial relationship between individuals and hinder behavioral reconstruction. Here, we report a Baltic amber inclusion preserving a female-male pair of the extinct termite species Electrotermes affinis. The head-to-abdomen contact in the fossilized pair resembles the tandem courtship behavior of extant termites, although their parallel body alignment differs from the linear alignment typical of tandem runs. To solve this inconsistency, we simulated the first stage of amber formation, the immobilization of captured organisms, by exposing living termite tandems to sticky surfaces. We found that the posture of the fossilized pair matches trapped tandems and differs from untrapped tandems. Thus, the fossilized pair likely is a tandem running pair, representing the direct evidence of the mating behavior of extinct termites. Furthermore, by comparing the postures of partners on a sticky surface and in the amber inclusion, we estimated that the male likely performed the leader role in the fossilized tandem. Our results demonstrate that past behavioral interactions can be reconstructed despite the spatial distortion of body poses during fossilization. Our taphonomic approach demonstrates how certain behaviors can be inferred from fossil occurrences.

A novel in-bed body posture monitoring for decubitus ulcer prevention using body pressure distribution mapping

BACKGROUND

Decubitus ulcers are prevalent among the aging population due to a gradual decline in their overall health, such as nutrition, mental health, and mobility, resulting in injury to the skin and tissue. The most common technique to prevent these ulcers is through frequent repositioning to redistribute body pressures. Therefore, the main goal of this study is to facilitate the timely repositioning of patients through the use of a pressure mat to identify in-bed postures in various sleep environments. Pressure data were collected from 10 healthy participants lying down on a pressure mat in 19 various in-bed postures, correlating to the supine, prone, right-side, and left-side classes. In addition, pressure data were collected from participants sitting at the edge of the bed as well as an empty bed. Each participant was asked to lie in these 19 postures in three distinct testing environments: a hospital bed, a home bed, and a home bed with a foam mattress topper. To categorize each posture into its respective class, the pre-trained 2D ResNet-18 CNN and the pre-trained Inflated 3D CNN algorithms were trained and validated using image and video pressure mapped data, respectively.

RESULTS

The ResNet-18 and Inflated 3D CNN algorithms were validated using leave-one-subject-out (LOSO) and leave-one-environment-out (LOEO) cross-validation techniques. LOSO provided an average accuracy of 92.07% ± 5.72% and 82.22% ± 8.50%, for the ResNet-18 and Inflated 3D CNN algorithms, respectively. Contrastingly, LOEO provided a reduced average accuracy of 85.37% ± 14.38% and 77.79% ± 9.76%, for the ResNet-18 and Inflated 3D CNN algorithms, respectively.

CONCLUSION

These pilot results indicate that the proposed algorithms can accurately distinguish between in-bed postures, on unseen participant data as well as unseen mattress environment data. The proposed algorithms can establish the basis of a decubitus ulcer prevention platform that can be applied to various sleeping environments. To the best of our knowledge, the impact of mattress stiffness has not been considered in previous studies regarding in-bed posture monitoring.

The influence of seated postures and anthropometry on lap belt fit in vehicle occupants: A 3D computed tomography study

OBJECTIVE

In vehicle frontal collisions, it is crucial that the lap belt is designed to engage with the anterior superior iliac spine (ASIS) of occupants for a reliable restraint. This study aims to understand the influence of different seated postures on the geometrical relationship of the seat belt and the pelvis for various occupants using 3D upright and supine computed tomography (CT) systems.

METHODS

The 3D shapes of bones and soft tissues around the pelvis were acquired through a CT scan for 30 participants. They were seated in a rigid seat equipped with a lap belt simulating the front seat of a small car, and wore a lap belt in three seated postures: upright, slouched and reclined. Parameters related to the likelihood of submarining occurrences, such as belt-ASIS overlap (an index for assessing the potential engagement of the lap belt with the ASIS) and the belt-pelvis angle (the difference between the belt angle and the normal direction of the anterior edge of the ilium) were compared.

RESULTS

It was observed that the pelvis angle tilted rearward as the hip point was positioned forward and seatback angle increased. This can be seen in the slouched and reclined posture. The belt-pelvis angle was comparable between the slouched and the reclined postures, and was closer to zero (indicating that the lap belt path is closer to perpendicular to the anterior edge of the ilium) compared to the upright posture. In contrast, the belt-ASIS overlap increased with an increasing flesh margin of the ASIS and shallower belt angle. This suggests that the belt-pelvis angle is influenced by the seated posture whereas the belt-ASIS overlap is dependent more on an individual's anthropometry. The plot of belt-pelvis angle and belt-ASIS overlap exhibited significant variability among participants.

CONCLUSIONS

The belt-pelvis angle and the belt-ASIS overlap of individuals will provide valuable information for understanding the current belt-fit location and predicting submarining occurrences for individuals in various postures when designing restraint systems.

Optimization of the seat position for a personal vehicle equipped with a crankset: pilot study

The aim of the study was to optimize the seat for a personal vehicle equipped with a crankset mechanism, meant for everyday use. The inclination of the seat backrest was selected on the basis of theoretical considerations. Then dynamic tests were carried out on a group of young, healthy men in order to verify the ergonomic aspects of the seat position in relation to the crankset and determine the efficiency of the human-mechanism system with a load of 50 W. The data obtained from the dynamic tests were subject to statistical analysis. Research has shown that higher seat positions result in statistically higher efficiencies. In addition, a holistic analysis of the personal vehicle design problem shows that the upper position of the seat is also the best. The results of the research can be used to optimize personal vehicles using human force as a drive.

Case of tizanidine withdrawal showing hallucination, decorticate posture and tremor, with hypersympathetic vital signs

Tizanidine, an α2-adrenergic receptor agonist commonly prescribed as a muscle relaxant, has been associated with limited cases of acute intoxication or withdrawal. Here, we present a case of tizanidine withdrawal in a woman in her 40s who presented with an unusual combination of systemic and neurological symptoms. These included hallucinations, decorticate posture, limb and eyelid tremors, along with hypertension, tachycardia and tachypnoea. The diagnosis of tizanidine withdrawal was established by a comprehensive assessment of the patient's medical history and the systematic exclusion of other potential diseases. Our approach to managing the withdrawal symptoms was to initiate symptomatic treatment with a combination of a beta-blocker and a calcium channel blocker. Remarkably, this intervention successfully resolved both vital signs and neurological manifestations by the following day. In conclusion, tizanidine withdrawal is associated with a distinct and diagnostically significant neurological syndrome characterised by hallucinations, decorticate posture, tremors and hypersympathetic vital signs.

An affordable and immersive virtual reality-based exercise therapy in forward head posture

Forward Head Posture (FHP) is one of the most commonly occurring musculoskeletal abnormalities. Despite exercise therapy being an effective approach for FHP treatment, it can be long, monotonous, and tedious. Virtual reality (VR) can be used as an innovative solution to address these challenges. We designed an affordable and immersive VR-based exercise therapy (VRET) system for FHP correction. The VRET contents (i.e., exercises and VR scenarios) were determined by physiotherapists and game designers at the focus group meetings. Hardware requirements include a VR box, smartphone, and sensors (i.e., a smartphone accelerometer and an affordable Inertial Measurement Unit (IMU)) to measure head motions and transfer them via Wi-Fi to the VRET system. The IMU was designed using the MPU6050, Arduino Nano, and ESP8266-01S. Gwet's AC1, Game Experience Questionnaires (GEQ), and System Usability Scale (SUS) were used to measure intra-rater reliability, user experience, and system usability, respectively. The determined exercises, including Capital Flexion-Extension and Chin Tuck, were designed in the form of a shooting game. A physiotherapist and twenty-one FHP individuals took part in evaluating the system. High precision was obtained for the designed IMU (i.e., pitch and roll < 0.1° and yaw < 1.3 °). Gwet's AC1 and SUS results showed very good intra-rater reliability (coefficient = 0.892) and excellent usability (score = 87.14), respectively. According to the mean scores of the GEQ, participants were confident about competence, immersion, flow, and positive affect components. The development of low-cost VRET systems for FHP correction is a step towards facilitating rehabilitation challenges by providing positive experiences for users as well as helping them perform therapeutic exercises correctly.

Influence of age on the relation between body position and noninvasively acquired intracranial pulse waves

The capacitive measurement of the head's dielectric properties has been recently proposed as a noninvasive method for deriving surrogates of craniospinal compliance (CC), a parameter used in the evaluation of space-occupying neurological disorders. With the higher prevalence of such disorders in the older compared to the younger population, data on the head's dielectric properties of older healthy individuals would be of particularly high value before assessing pathologic changes. However, so far only measurements on young volunteers (< 30 years) were reported. In the present study, we have investigated the capacitively obtained electric signal known as W in older healthy individuals. Thirteen healthy subjects aged > 60 years were included in the study. W was acquired in the resting state (supine horizontal position), and during head-up and head-down tilting. AMP, the peak-to-valley amplitude of W related to cardiac action, was extracted from W. AMP was higher in this older cohort compared to the previously investigated younger one (0°: 5965 ± 1677 arbitrary units (au)). During head-up tilting, AMP decreased (+ 60°: 4446 ± 1620 au, P < 0.001), whereas it increased during head-down tilting (- 30°: 7600 ± 2123 au, P < 0.001), as also observed in the younger cohort. Our observation that AMP, a metric potentially reflective of CC, is higher in the older compared to the younger cohort aligns with the expected decrease of CC with age. Furthermore, the robustness of AMP is reinforced by the consistent relative changes observed during tilt testing in both cohorts.

The modified Lyon's position: an alternative approach to robotic thymectomy

The conventional supine position for robotic thymectomy may present challenges in accessing the lower thymic horns, particularly in cases requiring extensive resection of mediastinal fat. To address this issue, the authors advocate for a lateral patient position during the procedure, emphasizing optimized access to the thymic horns and improved procedural efficacy. The lateral approach involves specific trocar placements and port arrangements to minimize conflicts between instruments. This report proposes an innovative approach to robotic thymectomy for patients diagnosed with thymoma or thymic hyperplasia associated with myasthenia gravis.

Craniocervical posture in patients with skeletal malocclusion and its correlation with craniofacial morphology during different growth periods

The association between craniocervical posture and craniofacial structures in the various sagittal skeletal malocclusion during different growth stages has been the focus of intense interest in fields of orthodontics, but it has not been conclusively demonstrated. Thus, this study aimed to investigate the association between craniofacial morphology and craniocervical posture in patients with sagittal skeletal malocclusion during different growth periods. A total of 150 from a large pool of cephalograms qualified for the inclusion and exclusion were evaluated and classified into three groups according to the Cervical Vertebral Maturation (CVM) by examining the morphological modifications of the second through fourth cervical vertebrae, each group consisted of 50 cephalograms. In each growth period, for the comparison of head and cervical posture differences among various skeletal classes, the radiographs were further subdivided into skeletal Class I (0° < ANB < 5°, n = 16), skeletal Class II (ANB ≥ 5°, n = 18), and skeletal Class III (0° ≤ ANB, n = 16) on the basis of their ANB angle. There was no significant difference in gender (P > 0.05). Some variables were found to be significant during pubertal growth and later in patients with sagittal skeletal malocclusion (P < 0.05). Most indicators describing craniocervical posture were largest in skeletal Class II and smallest in skeletal Class III during the peak growth periods and later. Cervical inclination variables were greater in skeletal Class III than in skeletal Class II. Variables of craniofacial morphology and craniocervical posture are more correlated during the pubertal growth period and later in patients with sagittal skeletal malocclusion. A tendency is an indication of the close interrelationship that a more extended head was in skeletal Class II while a flexed head was in skeletal Class III. Nevertheless, with the considerations of some limitations involved in this study, further longitudinal studies with large samples are required to elucidate the relationship clearly.

Rethinking the Ideal Body Posture for Otorhinolaryngologists

Surgeons have a high rate of work-related musculoskeletal injuries; an area that has received little attention. These injuries result in surgeons performing less efficiently, needing to take time off work, suffering higher rates of burnout, and may ultimately lead surgeons to retire earlier than planned. Otorhinolaryngologists are at particular risk for work-related musculoskeletal injuries. Beyond the clinician, sustaining such injuries can negatively impact patient safety. Ergonomic interventions have been used effectively to reduce work-related musculoskeletal injuries in other professions, yet not in surgery. With traditional teachings of ideal body postures to avoid injury and manual handling training being re-evaluated, it is important to explore evidence based interventions for reducing work-related musculoskeletal injuries in otorhinolaryngologists. New research encourages us to shift the focus away from the traditional one-size-fits-all approach to ergonomics and toward postural recommendations and education that promote a dynamic, individualized approach to avoiding sustained, static and awkward postures.