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This work aimed to investigate the association between the perceived cushioning of a set of trail-running shoes with both their mechanical response to the impact test and the acceleration of lower limb segments while running indoors and outdoors. Earlier studies have typically focussed on the effect of road-running shoe cushioning, whereas very few have examined the perception of trail runners and outdoor trail-running conditions. Seven trail runners were trained to become reliable in evaluating the level of cushioning on a scale ranging from 0 to 100 and then asked to rate the cushioning of eight trail-running shoes while running. Shoe specimens were mechanically characterized through an impact test. In addition, the effect on running biomechanics was tested by wearing two accelerometers on the tibia and foot. The in-lab impact test revealed that the perceived cushioning was inversely associated with the force amplitude and directly associated with the impact duration. The running test showed that the median frequency of the tibial acceleration during the first 25% of the stance phase decreases with increasing cushioning during both indoor (p = 0.02, rs = −0.83) and outdoor conditions (p < 0.001, rs = −0.79). In conclusion, the perceived cushioning was quantitatively associated with the outcomes of impact and running tests.

In recent years, the use of inertial-based systems has been applied to remote rehabilitation, opening new perspectives for outpatient assessment. In this study, we assessed the accuracy and the concurrent validity of the angular measurements provided by an inertial-based device for rehabilitation with respect to the state-of-the-art system for motion tracking. Data were simultaneously collected with the two systems across a set of exercises for trunk and lower limbs, performed by 21 healthy participants. Additionally, the sensitivity of the inertial measurement unit (IMU)-based system to its malpositioning was assessed. Root mean square error (RMSE) was used to explore the differences in the outputs of the two systems in terms of range of motion (ROM), and their agreement was assessed via Pearson’s correlation coefficient (PCC) and Lin’s concordance correlation coefficient (CCC). The results showed that the IMU-based system was able to assess upper-body and lower-limb kinematics with a mean error in general lower than 5° and that its measurements were moderately biased by its mispositioning. Although the system does not seem to be suitable for analysis requiring a high level of detail, the findings of this study support the application of the device in rehabilitation programs in unsupervised settings, providing reliable data to remotely monitor the progress of the rehabilitation pathway and change in patient’s motor function.

Non-contact injuries can occur when athletes use poor or inconsistent mechanics during typical sport-related movements like landing from a jump. Anterior cruciate ligament (ACL) injuries are especially devastating, and certain populations like female athletes and athletes with a previous ACL reconstruction (ACLR) are at greater risk of suffering an ACL injury, with altered biomechanical strategies being one proposed reason. Asymmetric landings where one limb experiences greater landing force can decrease joint stability and place the overloaded limb at greater risk for ACL injury. Additionally, a stiff landing, characterized by increased ground reaction force (GRF), extended joints at initial ground contact, and decreased joint flexion throughout the landing, has been proposed to increase ACL injury risk. While load distribution between limbs is a common landing assessment to determine injury risk, it is unclear what role limb stiffness plays in the likelihood of experiencing an ACL injury. Limb stiffness is simply the deformation of the limb in response to the downward force applied to the lower limb during ground contact, which can be approximated using GRF. Limb stiffness has been commonly used to assess performance in running, hopping, and jumping, however, its relationship with injury risk during landings is relatively unexplored. Past research has revealed that the ACL experiences peak strain prior to initial ground contact when the knee is at or near full extension. Additionally, expert video analyses have determined that ACL injuries most likely occur within 50 milliseconds of ground contact. It is possible that limb stiffness and limb stiffness asymmetry can be used during the early impact phase of landings to reveal ACLR- and sex-specific landing mechanics differences when the ACL appears to be most vulnerable. Moreover, game-like, sport-specific landing tasks with a greater horizontal component that load the ACL and those that divert attention away from landing strategies may uncover differences that do not appear in standard, controlled laboratory tasks. The overall goal of this project was to use limb stiffness, limb stiffness asymmetry, and related measures to analyze the early landing phase mechanics of groups at greater risk for ACL injury during game-like, sport-specific landings. First, in an ACLR cohort, greater knee power and knee work asymmetries were found when compared to healthy recreational athletes, supporting previous literature that found that athletes with an ACLR land unevenly by offloading their surgical limb. However, limb stiffness asymmetry was not different between groups, implying that the groups may have modulated limb stiffness differently between limbs. Second, minimal sex-by-task interactions were determined for landings that varied by horizontal approach prior to initial ground contact. Significant differences were found for most measures across tasks overall, however, male and female athletes displayed similar landing mechanics, indicating that expected sex-specific differences may not exist during the immediate landing phase when ACL injuries are thought to occur. Last a landing task that mimicked a ball in mid-air and diverted attention away from landing mechanics produced a sex-by-task interaction for peak impact force but no other measure. When comparing each sex-task pairing, a trend for greater peak impact force by female athletes during the distracted landing (p=0.098) was found which may indicate that future tasks with additional external focuses or another game-like component will reveal anticipated sex-specific differences. Increased time between limbs for initial ground contact for female athletes also revealed that a time-synchronized assessment of between-limb coordination may be beneficial for future research. Doctor of Philosophy Non-contact injuries can occur when athletes use poor or inconsistent mechanics during typical sport-related movements like landing from a jump. Anterior cruciate ligament (ACL) injuries are especially tough, and certain populations like female athletes and athletes with a previous ACL reconstruction surgery (ACLR) are at greater risk of suffering an ACL injury, with different movement techniques being one proposed reason. Uneven landings where one limb has greater landing forces can decrease joint posture and place the overloaded limb at greater risk for ACL injury. Additionally, a stiff landing, defined by larger ground reaction force (GRF), extended joints at initial ground contact, and decreased joint flexion throughout the landing, is thought to increase ACL injury risk. While landing force distribution between limbs is a common way of evaluating landings to determine injury risk, it is unclear what role limb stiffness plays in the likelihood of experiencing an ACL injury. Limb stiffness is simply the deformation of the limb in response to the downward force applied on the lower limb during ground contact, which can be estimated using GRF. Limb stiffness has been commonly used to assess performance in running, hopping, and jumping, however, its relationship with injury risk during landings is pretty limited. Past research has revealed that the ACL experiences maximum stretch prior to initial ground contact when the knee is or is almost completely straight. Additionally, expert video investigations have determined that ACL injuries most likely occur within 50 milliseconds of ground contact. It is possible that limb stiffness and limb stiffness asymmetry can be used during the early impact phase of landings to reveal sex- and ACLR-specific landing mechanics differences when the ACL appears to be most in danger. Additionally, game-like, sport-specific landing tasks with a greater horizontal element that load the ACL and those that redirect attention away from landing strategies may show differences that do not appear in basic laboratory tasks. The overall goal of this project was to use limb stiffness, limb stiffness asymmetry, and related measures to examine the early landing phase techniques of groups at greater risk for ACL injury during game-like, sport-specific landings. First, in a group of athletes with a previous ACLR, greater knee storage differences between limbs were found when compared to healthy recreational athletes, supporting previous research studies that found that athletes with an ACLR land unevenly by offloading their surgical limb. However, limb stiffness asymmetry was not different between groups, implying that the groups may have regulated limb stiffness differently between limbs. Second, only a couple measures were significantly affected by the combined effect of sex and task during landings that were different due to their horizontal element. Significant differences were found for most measures across tasks overall, however, male and female athletes had similar landing techniques, showing that the expected differences between sexes may not happen very early in the landing phase when ACL injuries are thought to happen. Last, a landing task that imitated a ball in mid-air and redirected attention away from landing mechanics produced a larger sex-specific difference for peak impact force compared to a basic landing task. When comparing each sex-task pairing, a trend for greater peak impact force by female athletes during the distracted landing (p=0.098) was found which may show that future tasks with additional distractions or another game-like element will reveal expected differences between sexes. Increased time between limbs for initial ground contact for female athletes also revealed that looking at the coordination of both limbs on the same timescale may be useful for future research.

Olympic-style sliding-seat rowing is a sport that has been extensively researched, with studies investigating aspects related to the physiology, biomechanics, kinematics, and the performance of rowers. In contrast, studies on the more classic form of fixed-seat rowing are sparse. The aim of this study is to address this lacuna by analysing for the first time the specific kinematics of fixed-seat rowing as practised by able-bodied athletes, thus (i) documenting how this technique is performed in a manner that is replicable by others and (ii) showing how this technique compares and contrasts with the more standard sliding-seat technique. Fixed-seat rowing was replicated in a biomechanics laboratory where experienced fixed-seat rowers, marked with reflective markers following the modified Helen–Hayes model, were asked to row in a manner that mimics rowing on a fixed-seat boat. The findings from this study, complimented with data gathered through the observation of athletes rowing on water, were compared to sliding-seat ergometer rowing and other control experiments. The results show that, in fixed-seat rowing, there is more forward and backward thoracic movement than in sliding-seat rowing (75–77° vs. 44–52°, p < 0.0005). Tilting of the upper body stems was noted to result from rotations around the pelvis, as in sliding-seat rowing, rather than from spinal movements. The results also confirmed knee flexion in fixed-seat rowing with a range of motion of 30–35°. This is less pronounced than in standard-seat rowing, but not insignificant. These findings provide a biomechanical explanation as to why fixed-seat rowers do not have an increased risk of back injuries when compared with their sliding-seat counterparts. They also provide athletes, coaches, and related personnel with precise and detailed information of how fixed-seat rowing is performed so that they may formulate better and more specific evidence-based training programs to meliorate technique and performance.

Introduction: The total number of confirmed cases of COVID-19 caused by the SARS-CoV-2 virus infection is over 621 million in the world. In approximately 63% of cases, the patient still experiences persistent symptoms 30 days after the onset of symptoms or hospitalisation, and 45.9% of patients have experienced or will experience symptoms for at least three months. Despite the prevalence of chronic symptoms and pathological changes that may affect gait and functional mobility in people with a history of COVID-19, there are few publications investigating the impact of these abnormalities. This study aims to determine the long-term effects of COVID-19 on gait and the Timed-Up and Go Task. Material and Methods: A total of 30 individuals took part in the experiment. The subjects in the study group were infected with the COVID-19 virus and required hospital treatment. Prior to the study, the subjects had no chronic diseases or other conditions affecting the musculoskeletal system. The non-infected by COVID-19 group was a healthy population with no history of COVID-19 disease. The study used the inertial system wireless motion analysis system based on 15 inertial sensors (inertial measurement units, IMUs). IMU sensors were placed on the following body segments: head, sternum, middle and lower spine, shoulder, arm, forearm, hand, shank, for the left and right limb. Movement task reports generated from the recording were created using myoRESEARCH 3.10. The subjects in the study group were asked to perform a movement task test—the Timed-Up and Go Test (TUG): sit-to-stand, walk (3 m) without change in direction, walk termination, and stand-to-sit. Results: It took 46% longer for those infected by COVID-19 (participants) to complete the entire movement task compared to those in the not-infected by COVID-19 group. Sit-to-Stand Time [s] was greater in the infected by COVID-19 group and was 2.1 ± 0.7. Mean Walking Speed [m/s] was lower than in the not-infected by COVID-19 group and was 0.26 ± 0.07. Walking cadence [steps/min] was lower and was 21.2 ± 1.2. Infected by COVID-19 participants achieved a smaller anterior pelvic tilt angle (p < 0.001) and a smaller hip flexion angle (p = 0.025), with an increase in knee (p < 0.001) and ankle (p < 0.001) flexion angles. Conclusions: Individuals in the infected by COVID-19 group present changes in the ranges of motion and the time to complete the TUG task, despite the fact that at least eight weeks passed after hospital discharge.

Measurement of reaction time in clinical settings is generally employed to assess cognitive abilities by having a subject perform standard simple tests. In this study, a new method of measuring response time (RT) was developed using a system composed of LEDs that emit light stimuli and are equipped with proximity sensors. The RT is measured as the time taken by the subject to turn off the LED target by moving the hand towards the sensor. Through an optoelectronic passive marker system, the associated motion response is assessed. Two tasks of 10 stimuli each were defined: simple reaction time and recognition reaction time tasks. To validate the method implemented to measure RTs, the reproducibility and repeatability of the measurements were estimated, and, to test the method’s applicability, a pilot study was conducted on 10 healthy subjects (6 females and 4 males, age = 25 ± 2 years), reporting, as expected, that the response time was affected by the task’s difficulty. Unlike commonly used tests, the developed method has proven to be adequate for the simultaneous evaluation of the response in terms of time and motion. Furthermore, thanks to the playful nature of the tests, this method could also be used for clinical and pediatric applications to measure the impact of motor and cognitive impairments on RT.

BackgroundMarkerless motion capture based on low-cost 2-D video analysis in combination with computer vision techniques has the potential to provide accurate analysis of running technique in both a research and clinical setting. However, the accuracy of markerless motion capture for assessing running kinematics compared to a gold-standard approach remains largely unexplored. ObjectiveHere, we investigate the accuracy of custom-trained (DeepLabCut) and existing (OpenPose) computer vision techniques for assessing sagittal-plane hip, knee, and ankle running kinematics at speeds of 2.78 and 3.33 m s(-1) as compared to gold-standard marker-based motion capture. MethodsDifferences between the markerless and marker-based approaches were assessed using statistical parameter mapping and expressed as root mean squared errors (RMSEs). ResultsAfter temporal alignment and offset removal, both DeepLabCut and OpenPose showed no significant differences with the marker-based approach at 2.78 m s(-1), but some significant differences remained at 3.33 m s(-1). At 2.78 m s(-1), RMSEs were 5.07, 7.91, and 5.60, and 5.92, 7.81, and 5.66 degrees for the hip, knee, and ankle for DeepLabCut and OpenPose, respectively. At 3.33 m s(-1), RMSEs were 7.40, 10.9, 8.01, and 4.95, 7.45, and 5.76 for the hip, knee, and ankle for DeepLabCut and OpenPose, respectively. ConclusionThe differences between OpenPose and the marker-based method were in line with or smaller than reported between other kinematic analysis methods and marker-based methods, while these differences were larger for DeepLabCut. Since the accuracy differed between individuals, OpenPose may be most useful to facilitate large-scale in-field data collection and investigation of group effects rather than individual-level analyses.

In this study, we introduce a novel design for a three-dimensional (3D) controller, which incorporates the omni-purpose stretchable strain sensor (OPSS sensor). This sensor exhibits both remarkable sensitivity, with a gauge factor of approximately 30, and an extensive working range, accommodating strain up to 150%, thereby enabling accurate 3D motion sensing. The 3D controller is structured such that its triaxial motion can be discerned independently along the X, Y, and Z axes by quantifying the deformation of the controller through multiple OPSS sensors affixed to its surface. To ensure precise and real-time 3D motion sensing, a machine learning-based data analysis technique was implemented for the effective interpretation of the multiple sensor signals. The outcomes reveal that the resistance-based sensors successfully and accurately track the 3D controller’s motion. We believe that this innovative design holds the potential to augment the performance of 3D motion sensing devices across a diverse range of applications, encompassing gaming, virtual reality, and robotics.

Recent advancements in computing and artificial intelligence (AI) make it possible to quantitatively evaluate human movement using digital video, thereby opening the possibility of more accessible gait analysis. The Edinburgh Visual Gait Score (EVGS) is an effective tool for observational gait analysis, but human scoring of videos can take over 20 min and requires experienced observers. This research developed an algorithmic implementation of the EVGS from handheld smartphone video to enable automatic scoring. Participant walking was video recorded at 60 Hz using a smartphone, and body keypoints were identified using the OpenPose BODY25 pose estimation model. An algorithm was developed to identify foot events and strides, and EVGS parameters were determined at relevant gait events. Stride detection was accurate within two to five frames. The level of agreement between the algorithmic and human reviewer EVGS results was strong for 14 of 17 parameters, and the algorithmic EVGS results were highly correlated (r > 0.80, “r” represents the Pearson correlation coefficient) to the ground truth values for 8 of the 17 parameters. This approach could make gait analysis more accessible and cost-effective, particularly in areas without gait assessment expertise. These findings pave the way for future studies to explore the use of smartphone video and AI algorithms in remote gait analysis.

The 5-Sit-to-stand test (5STS) is widely used to estimate lower limb muscle power (MP). An Inertial Measurement Unit (IMU) could be used to obtain objective, accurate and automatic measures of lower limb MP. In 62 older adults (30 F, 66 ± 6 years) we compared (paired t-test, Pearson’s correlation coefficient, and Bland-Altman analysis) IMU-based estimates of total trial time (totT), mean concentric time (McT), velocity (McV), force (McF), and MP against laboratory equipment (Lab). While significantly different, Lab vs. IMU measures of totT (8.97 ± 2.44 vs. 8.86 ± 2.45 s, p = 0.003), McV (0.35 ± 0.09 vs. 0.27 ± 0.10 m∙s−1, p < 0.001), McF (673.13 ± 146.43 vs. 653.41 ± 144.58 N, p < 0.001) and MP (233.00 ± 70.83 vs. 174.84 ± 71.16 W, p < 0.001) had a very large to extremely large correlation (r = 0.99, r = 0.93, and r = 0.97 r = 0.76 and r = 0.79, respectively, for totT, McT, McF, McV and MP). Bland–Altman analysis showed a small, significant bias and good precision for all the variables, but McT. A sensor-based 5STS evaluation appears to be a promising objective and digitalized measure of MP. This approach could offer a practical alternative to the gold standard methods used to measure MP.

Introduction: The functional outcome after reverse shoulder arthroplasty (RSA) is closely linked to how much the humerus shifts because of the implants. While two-dimensional (2D) angle measurements have been used to capture this shift, it can be measured in three dimensions (3D) as the arm change position (ACP). In a previous study, the ACP was measured using 3D preoperative planning software with the passive virtual shoulder range of motion obtained after RSA. The main objective of this study was to evaluate the relationship between the ACP and the actual active shoulder range of motion measured after RSA. The hypothesis was that the ACP and the active clinical range of motion are related such that the ACP is a reliable parameter to guide the preoperative planning of an RSA. The secondary objective was to assess the relationship between 2D and 3D humeral displacement measurements. Materials and methods: This prospective observational study enrolled 12 patients who underwent RSA and had a minimum follow-up of 2 years. The active range of motion in shoulder flexion, abduction, and internal and external rotation was measured. At the same time, ACP measurements were taken from a reconstructed postoperative CT scan, in addition to the radiographic measurements of humeral lateralization and distalization angles on AP views in neutral rotation. Results: The mean humeral distalization induced by RSA was 33.3 mm (±3.8 mm). A non-statistically significant increase in shoulder flexion was observed for humeral distalization beyond 38 mm (R2 = 0.29, p = 0.07). This “threshold” effect of humeral distalization was also observed for the gains in abduction, as well as internal and external rotations, which seemed better with less than 38 mm or even 35 mm distalization. No statistical correlation was found between the 3D ACP measurements and 2D angle measurements. Conclusion: Excessive humeral distalization seems to be detrimental to joint mobility, especially shoulder flexion. Humeral lateralization and humeral anteriorization measured using the ACP seem to promote better shoulder range of motion, with no threshold effect. These findings could be evidence of tension in the soft tissues around the shoulder joint, which should be taken into consideration during preoperative planning.

The “Be an Airplane Pilot” (BE API) protocol was developed to evaluate upper limb (UL) kinematics in children with unilateral cerebral palsy (uCP) during bimanual tasks. The aim of this study was to investigate the responsiveness of this protocol to changes in kinematics and movement quality after UL therapies, using individual and group analyses, and to analyse the relationships between kinematic and functional changes in these children. Twenty children with uCP (5–15 years old) either participated in bimanual intensive therapy or received UL botulinum toxin injections. All the children performed the BE API protocol and functional assessments (Assisting Hand Assessment [AHA]) before and after the interventions. The individual analyses found kinematic changes in 100% of the children after therapy. The group analysis found significantly higher trunk and shoulder deviations after the intensive therapy. No significant changes were found for smoothness or trajectory straightness. The changes in the kinematic deviations were moderately correlated with the changes in the AHA scores. This study confirmed the responsiveness of the BE API protocol to change after therapy; therefore, the protocol is now fully validated and can be implemented in clinical practice. Its use should help in the accurate identification of impairments so that individualized treatments can be proposed.

An adaptive wheel-legged shape reconfigurable mobile robot, based on a scissor-like mechanism, is proposed for an obstacle detecting and surmounting robot, moving on complex terrain. The robot can dynamically adjust its own shape, according to the environment, realizing a transformation of wheel shape into leg shape and vice versa. Each wheel-legged mechanism has one degree of freedom, which means that only the relative motion of the inner and outer discs is needed to achieve the transformation of the shape into a wheel or a leg. First, the force analysis of the conversion process of the wheel-legged mechanism is carried out, while the relationship between the driving torque and the friction factor in the non-conversion trigger stage and in the conversion trigger stage is obtained. The results showed that the shape conversion can be better realized by increasing the friction factor of the trigger point. Next, the kinematics analysis of the robot, including climbing the obstacles, stairs and gully, is carried out. The motion of the spokes tip is obtained, in order to derive the folding ratio and the surmountable obstacle height of the wheel-legged mechanism. The parameters of the wheel-legged structure are optimized, to obtain better stability and obstacle climbing ability. Finally, a dynamic simulation model is established by ADAMS, to verify the obstacle climbing performance and gait rationality of the robot, in addition to a prototype experiment. The results showed that the surmountable obstacle height of the robot is about 3.05 times the spoke radius. The robot has the stability of a traditional wheel mechanism and the obstacle surmount performance of a leg mechanism, making it more suitable for field reconnaissance and exploration missions.

Purpose This study explores the biomechanics underlying the sit-to-stand (STS) functional maneuver in chronic LBP patients to understand how different spinal disorders and levels of pain severity relate to unique compensatory biomechanical behaviors. This work stands to further our understanding of the relationship between spinal loading and symptoms in LBP patients. Methods We collected in-clinic motion data from 44 non-specific LBP (NS-LBP) and 42 spinal deformity LBP (SD-LBP) patients during routine clinical visits. An RGB-depth camera tracked 3D joint positions from the frontal view during unassisted, repeated STS maneuvers. Patient-reported outcomes (PROs) for back pain (VAS) and low back disability (ODI) were collected during the same clinical visit. Results Between patient groups, SD-LBP patients had 14.3% greater dynamic sagittal vertical alignment (dSVA) and 10.1% greater peak spine torque compared to NS-LBP patients (p p p = 0.04) compared to NS-LBP patients. There were no significant differences between patient groups in regard to anterior or vertical torso velocities, but anterior and vertical torso velocities correlated with both VAS (r = − 0.38, p r = − 0.29, p = 0.01). PROs did not correlate with other variables. Conclusion Patients with LBP differ in movement biomechanics during an STS transfer as severity of symptoms may relate to different compensatory strategies that affect spinal loading. Further research aims to establish relationships between movement and PROs and to inform targeted rehabilitation approaches.

Temporal dominance (TD) methods can be used to record temporal changes in multiple sensory and affective responses. TD methods have found wide applications in the analysis of eating experiences of humans. However, extant analyses performed on TD data do not fully utilize the time-series properties of such data. The present study validates the prospect of principal motion analysis (PMA) of TD data. PMA is an extension of principal component analysis, and can be used to resolve multivariate motion data into base principal motions. In this study, panelists were asked to evaluate the tastes of ten types of pickled plums using the temporal dominance of sensations (TDS) and emotions (TDE) methods. Additionally, the panelists were asked to rate the plums using the semantic differential method. Results obtained using both methods were observed to demonstrate good agreement with each other in terms of the structures of reduced variable spaces. As realized in this study, implementation of the combined TD-PMA approach can potentially facilitate statistical discrimination of all food products, whereas conventional methods, such as principal component analysis of data provided via use of the semantic differential method, can at best discriminate only 67% of product pairs. PMA can, therefore, be considered as a suitable technique to reveal the characteristics of TD data.

The analysis of gait patterns and plantar pressure distributions via insoles is increasingly used to monitor patients and treatment progress, such as recovery after surgeries. Despite the popularity of pedography, also known as baropodography, characteristic effects of anthropometric and other individual parameters on the trajectory of the stance phase curve of the gait cycle have not been previously reported. We hypothesized characteristic changes of age, body height, body weight, body mass index and handgrip strength on the plantar pressure curve trajectory during gait in healthy participants. Thirty-seven healthy women and men with an average age of 43.65 ± 17.59 years were fitted with Moticon OpenGO insoles equipped with 16 pressure sensors each. Data were recorded at a frequency of 100 Hz during walking at 4 km/h on a level treadmill for 1 minute. Data were processed via a custom-made step detection algorithm. The loading and unloading slopes as well as force extrema-based parameters were computed and characteristic correlations with the targeted parameters were identified via multiple linear regression analysis. Age showed a negative correlation with the mean loading slope. Body height correlated with Fmeanload and the loading slope. Body weight and the body mass index correlated with all analyzed parameters, except the loading slope. In addition, handgrip strength correlated with changes in the second half of the stance phase and did not affect the first half, which is likely due to stronger kick-off. However, only up to 46% of the variability can be explained by age, body weight, height, body mass index and hand grip strength. Thus, further factors must affect the trajectory of the gait cycle curve that were not considered in the present analysis. In conclusion, all analyzed measures affect the trajectory of the stance phase curve. When analyzing insole data, it might be useful to correct for the factors that were identified by using the regression coefficients presented in this paper.

The present study describes the development of a wearable device designed to assist those who work in an unstructured posture. In the manufacturing sector, industrial accidents have been steadily on the rise due to poor work environments and excessive workloads imposed on workers. Against this backdrop, the present study aimed to analyze various types of work, especially those performed in unstructured postures by heavy industry workers, who are frequently exposed to high workloads and poor work environments. Based on the analysis results, an attempt was made to develop a shoulder muscle-assistive wearable device capable of assisting a wearer who is working using their shoulder muscles. Various types of unstructured posture work are performed in heavy industries, including activities such as the welding and grinding of ship components and plant structures. They are typically conducted in narrow spaces with limited postures, causing many workers to suffer muscle fatigue. In the present study, as the first step of developing a shoulder muscle-assistive wearable device, different working scenarios were simulated, and the corresponding motion data and required torque values were estimated using motion capture devices. The obtained motion data and required torque values were reflected in the design of the wearable device. The main structural body of the shoulder muscle-assistive wearable device was made of a carbon fiber-reinforced composite to be lightweight. This shoulder muscle-assistive wearable device was designed to fully cover the range of motion for workers working in unstructured postures while generating the torque required for a given job, thereby enhancing the muscular endurance of the workers. The gravity compensation module of the designed shoulder muscle-assistive wearable device generates a support force of 4.47 Nm per shoulder. The shoulder muscle assistive wearable device was developed to provide support for approximately 30% of the shoulder joint’s maximum torque generated in overhead tasks. This shoulder muscle-assistive wearable device is expected to contribute to improving the productivity of field workers, while reducing the occurrence of musculoskeletal injuries arising from the aging of the working-age population.

The purpose of this study was to clarify the characteristics of lower-extremity kinematics during the running of soccer players with chronic ankle instability (CAI) in comparison to those without CAI. Twenty-two male college soccer players participated in this study. Twelve players were assigned to the CAI group and ten players to the non-CAI group, and players were diagnosed according to the Cumberland Ankle Instability Tool. Kinematic data of the hip, knee, ankle, foot, and ground reaction force components during the stance phase of running were obtained using a three-dimensional motion analysis system. The results revealed that soccer players with CAI who landed with ankle inversion and other characteristic kinematics in their lower extremity during the stance phase of running were similar to those without CAI. These results show that running kinematics in soccer players are not affected by the presence or absence of CAI. Future studies based on the results of this study may contribute to the analysis of the risk of developing CAI during soccer and may also help prevent lateral ankle sprains.

Regardless of the type of sport, coaches must perform the difficult task of evaluating the performance of athletes. In some cases, this task is aided using technology which provides tools for this purpose. When the sport considered is taekwondo this scenario does not apply as the athlete evaluation methods used are mostly manual. Thus, the project presented in this paper has the main objective to develop a system that can be used as a tool to evaluate the performance of taekwondo athletes in real time, with special attention to the low cost of implementation and ease of use. With the intention of meeting these requirements, the developed system comprises a 3D camera with a depth sensor (Orbbec Astra), Inertial Measurement Units (IMUs) with accelerometer and gyroscope, a computer and specific software developed for this purpose. This system allows the collection of data from the athletes’ movements necessary for the creation of a dataset that is then analyzed and interpretated. The system permits the user to obtain real-time information about the speed, acceleration, and strength of the athlete’s limbs during training as well as the identification of some movements and their accounting. To achieve this functionality, deep-learning architecture models were used, more specifically long short-term memory (LSTM). The intention is to provide a new training methodology through faster feedback, so that a faster evolution of the athlete’s performance is possible, contributing to the technological development of the assessment practices used in taekwondo., This research was funded by FCT—Fundação para a Ciência e Tecnologia (Portugal) grant number SFRH/BD/121994/2016 and FCT RD Units Projects Scope: UIDB/04077/2020, UIDB/00319/2020, UIDB/05549/2020 and UIDP/05549/2020.

Background: The aim of this study was to analyze differences in three-dimensional shoulder kinematics between asymptomatic subjects and patients who were diagnosed with rotator cuff tears. Methods: This cross-sectional study recruited 13 symptomatic subjects and 14 asymptomatic subjects. Data were obtained from three inertial sensors placed on the humerus, scapula and sternum. Kinematic data from the glenohumeral, scapulothoracic and thoracohumeral joints were also calculated. The participants performed shoulder abductions and flexions. The principal angles of movements and resultant vectors in each axis were studied. Results: The glenohumeral joint showed differences in abduction (p = 0.001) and flexion (p = 0.000), while differences in the scapulothoracic joint were only significant during flexion (p = 0.001). The asymptomatic group showed higher velocity values in all sensors for both movements, with the differences being significant (p < 0.007). Acceleration differences were found in the scapula during abduction (p = 0.001) and flexion (p = 0.014), as well as in the sternum only during shoulder abduction (p = 0.022). Conclusion: The results showed kinematic differences between the patients and asymptomatic subjects in terms of the mobility, velocity and acceleration variables, with lower values for the patients.

The crucial criteria when assessing technical performance in artistic gymnastics is the higher elevation of the gymnast’s body and a stable landing (i.e., stick-landing). The purpose of this study was to compare kinetic and kinematic parameters during the landing phase of standing back somersaults (SBS) following three technical arm-swing performed during the preparatory phase in high-level male gymnasts. The three different arm-swing pertain to three “gymnastics schools”, i.e., Russian, Chinese, and Romanian. Six high-level male gymnasts participated in this study. Three arm-swing with different angles (i.e., SBS270°, SBS180°, and SBS90°) were randomly performed. A 3D kinetic and kinematic analysis was conducted. Results showed significant variation in the landing angle (p = 0.009) across the three arm-swing techniques. The SBS90° arm-swing resulted in the closest angle to the vertical. Additionally, the SBS90° arm-swing technique induced the lowest horizontal and vertical force values upon landing compared to the other arm-swing techniques (SBS270°: p = 0.023 and 0.009, respectively; SBS180°: p = 0.004 and 0.080, respectively). The same was noted for the horizontal velocity (p = 0.021) with the lowest values noted for the SBS90° arm-swing technique. However, the best opening angle was observed during the SBS270° technique, since it presented the best vertical displacement. In conclusion, the SBS with a SBS90° arm-swing seems to favor a better absorption of the ground reaction force upon landing by reducing the intensity of the impact with the ground and by affording a landing angle closer to the vertical in high-level male gymnasts.

CrossFit® has gained popularity as a functional training method that caters to individuals with varying levels of fitness, including those with little to no athletic background. Regardless, shoulders represent the highest injury rate in this sport, most frequently associated with pull-up variations. Therefore, ensuring safety during these movements is crucial. This thesis utilized optical motion tracking, force sensors, and Electromyography to measure nine experienced non-professional CrossFit® athletes performing three pull-up techniques used in CrossFit® (strict, kipping, and butterfly). Data were used in musculoskeletal modeling to assess and compare kinematics, kinetics, and muscle activations. Findings were then associated with common injury factors observed in overhead athletes. The novel dataset generated in this study demonstrated excellent repeatability and revealed significant differences between the techniques for most kinematic and kinetic variables, while variations in muscle activations were less systematic. Results indicated shoulder joint angles linked to impingement risk, with the kipping pull-up displaying more prominent risk factors. The butterfly pull-up exhibited extreme angular velocities and negative joint powers; however, direct associations with injuries could not be established. Notably, shoulder joint moments were high in all three techniques, suggesting significant muscle stresses. These results underscore the importance of individualized training load management to mitigate the risk of overuse injuries. Furthermore, the evidence presented in this study supports the importance of maintaining proper mechanics and developing strength before attempting kipping and butterfly pull-ups. The high joint moments, combined with severe positions and velocities observed during these techniques, highlight the necessity of prioritizing foundational strength and technique to minimize injury risks. CrossFit® har blivit populärt som en funktionell träningsmetod som lockar individueller med olika fitnessnivåer, även de utan tidigare idrottserfarenhet. Trots detta utgör axelskada den högsta skadefrekvensen inom denna sport och är oftast förknippad med räckhäv varianter. Därför är det avgörande att garantera säkra övningarna. Denna studie använde optisk rörelsespårning, kraftsensorer och elektromyografi för att mäta nio tränade icke-professionella CrossFit® atleter utförande av tre olika räckhäv tekniker som används inom CrossFit® (strikta, kipping och butterfly). Data användes för muskuloskeletala modeller för att uppskatta och jämföra kinematik, kinetik och muskelaktivering. Resultaten förknippades med till vanliga skadefaktorer som observeras hos overhead-idrottare. Det nya datasetet som genererades i denna studie visade utmärkt repeterbarhet och avslöjade signifikanta skillnader mellan teknikerna för de flesta kinematiska och kinetiska variablerna, medan variationer i muskelaktiveringar var mindre systematiska. Resultaten visade på axelledens vinklar som var kopplade till inklämningsrisk, där kipping pull-up uppvisade mer framträdande riskfaktorer. Butterfly pull-up uppvisade extrema vinkelhastigheter och negativa ledkrafter; men direkta samband med skador har inte upprättats. Det är anmärkningsvärt att axelledsmomenten var höga i alla tre tekniker, vilket tyder på betydande muskelspänningar. Dessa resultat understryker vikten av individualiserad hantering av träningsbelastning för att minska risken för överbelastningsskador. Dessutom stöder de bevis som presenteras i den här studien vikten av att behålla rätt mekanik och utveckla styrka innan man försöker göra kipping och butterfly pull-ups. De höga ledmomenten i kombination med svåra positioner och hastigheter som observerades under dessa tekniker lyfter fram behovet av att prioritera grundläggande styrka och teknik för att minimera risk för skador.

Objective: To compare the physical demands among training and match activities in women beach volleyball players. Design: Cross-sectional study. Setting: World top-level beach volleyball team. Patients or Other Participants: One defender (24 years-old, and 8 years of professional experience) and one blocker (25 years-old, and, 9 years of professional experience) from the Brazilian National Women’s Beach Volleyball participated in this study. Main outcome measure(s): Both players were monitored throughout on-field training sessions (N= 57) and matches (N=33) during the five months prior to the 2022 World Championship. Activities were categorized into formal-match (FM), match warm-up (MWU), physical training (PT), and tactical-technical (TT) training. We assessed field time, Player LoadTM, total jumps, total distance covered, and number of changes of direction to the right and left. Results: The defender and blocker players, showed large significant differences between the formal match and training activities. Both positions showed higher values of activity during formal matches than match warm-up and physical training activities. Also, tactical-technical training activities showed significant differences when compared to formal matches in both positions. Conclusions: Physical activities during formal matches were more demanding than during match warm-up and physical training activities. However, tactical-technical training activities were more demanding than formal-match activities. Coaches could use similar values (adjusted to their teams and competitive level) to distribute external load during the competitive period and better adjust the activity profile during training sessions. Future research should explore the relationship between the players’ perceptions (i.e., qualitative approach) and these findings.

本研究では、調理頻度や得意意識の異なる者を対象者に包丁動作分析を行い、客観的な評価方法の検討を行うことを目的とした。和洋女子大学教職員33名（男性9名、女性24名）を対象にし、長さと太さを調整したきゅうりを用いた輪切りの薄切りを実施した。包丁には「携帯型電気生理計測装置 超小型無線生体モニターマイクロDAQターミナル」を取り付け、動作解析を行った。分析項目は、20秒あたりの包丁の1ストローク所要時間、包丁動作（包丁サイクル・振り下ろし・振り上げ、前・後方向）の加速度とした。切断物に関しては薄切りの枚数、厚みを分析した。加えて、調理頻度や得意意識をアンケート調査した。20秒間のきゅうりの薄切りの枚数は、対象者の調理頻度より、本人の自己評価である得意意識の方が関連することが示され、対象を「得意群」、「中間群」、「不得意群」に分類し分析した。輪切り枚数、厚みは、「得意群」、「不得意群」間に有意差があり、包丁サイクルは「得意群」の方が「不得意群」より1サイクルの時間が有意に短く、包丁の振り下ろし・振り上げの最大加速度が有意に大きいことが認められた。 以上の結果から、輪切り枚数、厚み、包丁サイクル、振り下ろし・振り上げの最大加速度の指標を用いることで、包丁技術の上達の経緯を客観的な数値を用いて評価することが可能になると考えられた。

The COVID-19 pandemic has transformed daily life, as individuals engage in social distancing to prevent the spread of the disease. Consequently, patients' access to outpatient rehabilitation care was curtailed and their prospect for recovery has been compromised. Telerehabilitation has the potential to provide these patients with equally-efficacious therapy in their homes. Using commercial gaming devices with embedded motion sensors, data on movement can be collected toward objective assessment of motor performance, followed by training and documentation of progress. Herein, we present a low-cost telerehabilitation system dedicated to bimanual exercise, wherein the healthy arm drives movements of the affected arm. In the proposed setting, a patient manipulates a dowel embedded with a sensor in front of a Microsoft Kinect sensor. In order to provide an engaging environment for the exercise, the dowel is interfaced with a personal computer, to serve as a controller. The patient's gestures are translated into interactive actions in a custom-made citizen-science project. Along with the system, we introduce an algorithm for classification of the bimanual movements, whose inner workings are detailed in terms of the procedures performed for dimensionality reduction, feature extraction, and movement classification. We demonstrate the feasibility of our system on eight healthy subjects, offering support to the validity of the algorithm. These preliminary findings set forth the development of precise motion analysis algorithms in affordable home-based rehabilitation.

We developed an IoT wristband for basketball shooting analysis, which can provide a quantified shooting guidance for basketball players in a convenient and low-cost manner. An Inertial Measurement Unit (IMU) sensor-based wristband was used to collect the shooting motion data of 20 players with different level of skills, including 15 amateur basketball players and 5 elite players. The size of the wristband is 247mm × 20mm × 11mm, with a weight of 12.3g, which is small and lightweight. Its chip consists of a power system, a microcontroller and an IMU sensor (MPU-9250), which can acquire data of 3-axis acceleration, 3-axis angular velocity and 3-axis magnetic field data, and then transmit the data to a computing platform via Bluetooth. After correlation analysis, we use the data of triaxial acceleration and triaxial angular velocity to identify these 18 shooting movements. As experiment result shows, the four categories of shooting movements (i.e., set shots, layups, jump shots, and tip-ins) could be recognized at an accuracy of 98.0%. The overall recognition accuracy of 18 kinds of shooting movements is up to 98.5%. Furthermore, the AI-wristband can also be used for distinguishing the identity of participants, with a recognition rate of 97.4%, respectively. This new technology can be applied to quantitative basketing shot-making guidance, and potentially have applications for other motions and sports such as table tennis, racquetball, volleyball, and soccer.

Horse-rider interaction analysis by wearable sensors is a promising tool for monitoring equestrian training. In this paper, a body sensor network (BSN) based equestrian motion analysis system is developed, which combines bespoke inertial measurement units and MindWave electroencephalography (EEG) acquisition equipment. To fuse the mechanical and EEG signals collected from the system, emotional and attitude information can be obtained to analyze the interaction between the rider and horse in equestrian training. For motion data fusion, a novel method, exercise intensity extend kalman filter (EID-EKF), is proposed, which can also reconstruct the riders' posture in by establishing a biomechanical model. The accuracy of our method is verified with the optical system Vicon to support the motion capture for four riding styles. Finally, the emotion changes of the riders with different levels are quantified, and kinematic analysis is carried out by combining with inertial and emotional information. It is concluded from the experiment results that the estimation errors are well controlled, and motion patterns acquired according to the kinematic analysis are consistent with the actual situation.

An automatic protection guard for bikes reduces the impact to the side panels, engine, and the rider's leg when the bike collides with the ground, which follows the reverse quick return mechanism. Include a tilt sensor to monitor the bike's lean angle to activate the system and a wave spring inside the hollow bars to absorb the impact. A tilt sensor will be installed and will set a lean angle to the system. When the bike crosses the calibrated lean angle, the system activates and releases the bars from the system installed onto the bike frame and will take the first contact with the ground surface. To match real-life situations, the time taken for the protection guards to move from initial position to extreme position has been calculated using solid Works motion analysis with an average time taken is 0.14 s, and to find the total deformation different loads and different spring constants have been applied using Ansys software the average deformation is 12 mm. The system helps the rider to ride the bike in a safe mode. The total design system is dynamic and varies with the bike segment but follows the same mechanism.

Study Design This is a validation study. Background Tracking limb movement with body worn sensors allows clinicians to measure limb dynamics to guide treatment for patients with movement disorders. The current gold standard, 3-dimensional optical motion capture, is costly, time-consuming, requires specific training, and is conducted in specialized laboratories. Purpose The purpose of our study was to a compare consumer-grade inertial sensor to a laboratory-grade sensor to provide additional methods for capturing limb dynamics. Methods The participants wore an Apple Watch and a laboratory-grade Xsens sensor on each wrist during 3 conditions: walk, fast-walk, and run. Acceleration data were collected simultaneously on each device per wrist for all conditions. Intraclass correlation coefficients and Bland-Altman plots were calculated to measure intra-/interdevice reliability, evaluate bias, and limits of agreement. Results Intradevice ICCs showed good reliability during walk and fast-walk (0.79-0.87) and excellent reliability during run (0.94-0.97) conditions. Inter-device ICCs yielded moderate reliability during walk (0.52 ± 0.22) and excellent reliability in fast-walk and run (0.93 ± 0.02, 1.00 ± 0.01) conditions. Bland-Altman plots showed small biases with 90% or more of the data contained within the limits of agreement. Discussion Our study demonstrates reliability and agreement between the two devices, suggesting that both can reliably capture upper extremity motion data during gait trials. Conclusion Our findings support further study of consumer-grade motion trackers to measure arm activity for clinical use. These devices are inexpensive, user-friendly, and allow for data collection outside of the laboratory.

This article is to study the system structure scheme based on Zigbee wireless transmission, and complete the overall design of the system scheme on this basis. Human motion capture systems are widely used in the creation of film and television works, motion analysis, video games, rehabilitation medicine and other fields. This article discusses the design and implementation of a human motion capture system based on MEMS sensors and Zigbee networks. The system can be installed on the human body Multiple sensor nodes in various parts obtain the movement information of the human body, and use sensor network technology to aggregate these data and upload them to the host computer. First, this article introduces the characteristics of angular velocity sensors, acceleration sensors, magneto resistive sensors and Zigbee networks. Then, this article explains the overall structure of the system, and from a theoretical point of view, explains how the system uses angular velocity sensors, acceleration sensors, magneto resistive sensors and Zigbee networks to achieve human motion capture. This part focuses on including vector observation methods and angular velocity Two posture capture methods including the integration method, and their advantages and disadvantages are analyzed. To achieve the complementary advantages of the two algorithms, a data fusion algorithm based on complementary filtering is introduced and optimized appropriately. In addition, this article also introduces the networking principles and optimization schemes of the Zigbee network in this section. After this, this article explains in detail the system hardware structure, chip selection scheme, circuit design scheme, software workflow and implementation of core programs Method. Finally, this article shows the effect of the actual work of the system, and compares it with the theory to verify the feasibility of the theory. Based on the research of MEMS sensor measurement unit and algorithm, a Zigbee-based wireless transmission test system was established. LabVIEW software with functions of data reception, attitude angle calculation, trajectory calculation, eigenvalue extraction, BP neural network recognition, display and data saving was designed and tested the whole system functions. The test results show that the wireless data transmission of Zigbee network is normal, the data detection and processing programs of the host computer are stable, and the correct identification of the human body’s motion state can be realized. The results show that compared with the existing research, our research has increased its efficiency by 10%, and its accuracy has increased by nearly 15%.

Wireless sensors are a new, high-end, and popular exploration technology. The positioning and tracking of the human body are two important research issues in sensors. Aerobics is a widely popular sports item that is well-loved by the general public and integrates gymnastics, dance, music, fitness, and entertainment. The application of smart sensors helps to improve the coordination and flexibility of movements. In order to deeply study whether wireless smart sensors can play a role in tracking and recognizing aerobics exercise postures, this article uses sensor design methods, motion analysis, and software and hardware equipment architecture methods to collect samples, analyze smart sensors, and streamline algorithms. And it creates a sensor model and system for posture tracking and recognition. When testing the best position for the placement of the sensor, first fix the sensor at a distance of 2.5 cm from the wrist section and at the middle of the lower arm, keep the upper arm still, and do the stretching and contraction movements of the lower arm. Repeat the exercise 5 times and measure the wrist. The movement curve of the juncture, the result shows that the measured juncture curve at a distance of 2.5 cm is basically the same as the actual winding curve, and the fixed position in the middle deviates more from the normal curve point, and its average error is within 0.9 cm, which is correct. To test the effectiveness of the algorithm again, a total of 8 volunteers’ data were collected during the experiment, and the duration was more than 25 seconds, and each normal posture tried to maintain stability and lasted for about 6 seconds. The statistical accuracy rate is 90.6%. It shows that the algorithm or the system designed in this paper has extremely high accuracy. It is basically realized that from the theory of wireless sensor network, a system model that can be used for posture tracking and recognition of aerobics is designed.

BackgroundCam and/or pincer morphologies (CPM) are potential precursors to hip osteoarthritis (OA) and important contributors to non-arthritic hip pain. However, only some CPM hips develop OA and/or pain, and it is not clear why. Anterior impingement between the femoral head/neck contour and acetabular rim during motion is a proposed pathomechanism. Understanding how activity and deformity combine to produce impingement may shed light on the causes of hip degeneration/pain. The objective of this study was to determine the accuracy of a subject-specific hip model driven by subject-specific motion data in predicting anterior impingement.MethodsWe recruited 22 participants with CPM (both with and without pain) and 11 controls. We collected subject-specific 3D kinematics during squatting and sitting flexion, adduction, and internal rotation (FADIR) (an active and a passive maneuver, respectively, proposed to provoke impingement). We then developed 3D subject-specific hip models from supine 3T hip MRI scans that predicted the beta angle (a measure of anterior femoroacetabular clearance) for each frame of acquired kinematics. To assess the accuracy of these predictions, we measured the beta angle directly in the final position of squatting and sitting FADIR using open MRI scans. We selected the frame of motion data matching the static imaged posture using the least-squares error in hip angles. Model accuracy for each subject was calculated as the absolute error between the open MRI measure of beta and the model prediction of beta at the matched time frame. To make the final model accuracy independent of goodness of match between open MRI position and motion data, a threshold was set for least-squares error in hip angles, and only participants that were below this threshold were considered in the final model accuracy calculation, yielding results from 10 participants for squatting and 7 participants for sitting FADIR.ResultsFor squatting and sitting FADIR, we found an accuracy of 1.1°(0.8°) and 1.3°(mean (SD), and root mean squared error, respectively) and 0.5°(0.3°) and 0.6°, respectively.ConclusionThis subject-specific hip model predicts anterior femoroacetabular clearance with an accuracy of about 1°, making it useful to predict anterior impingement during activities measured with motion analysis.

This study's purpose was to compare the kinematic demands placed on the knee and the hip during various biomechanical tests.Retrospective cross-sectional design.A university research laboratory.The study sample consisted of 70 NCAA Division I female athletes.During the performance of three test maneuvers, a drop vertical jump (DVJ), single leg cross over hop (COH) and modified T-test (AT), the hip and knee joint angles at maximum knee valgus were obtained from marker displacement data collected using a 20-camera motion analysis system. A linear mixed model was used to compare the effect of test on joint angle.A significant difference (p 0.001) in the frontal and sagittal plane position of the knee and hip was noted between the DVJ, COH, and AT tests at maximum knee valgus.The DVJ, COH, and AT maneuvers do not appear to place the same kinematic stress on the knee, supporting the need for the development of return to sport tests that mimic on field demands.

The basic technique of kicking in pencak silat was often overlooked due to the consideration of increasing the level of the athlete and not on competence or skill. The purpose of this study was to identify biomechanics analysis of pencak silat side kick of Persinas ASAD. This study used quantitative research to obtain data derived from video recordings of sidekick movements that were analyzed using the Dartfish version 8. The total participants in this test were 30 Persinas ASAD martial arts athletes. This study recorded 30 martial arts athletes from Persinas ASAD with an average age (15.37 ± 1.45 years old), height (160 ± 7.9 cm), weight (50.37 ± 8.61 kg), and leg length (86.37 ± 5.73 cm). The results of side kick motion analysis data are obtained from the video analysis using Dartfish version 8 where the focus of the movement is divided into 3 main phases. These phases include the horse stance, the take-off phase, and the impact phase. The results found that the fighters are in the appropriate category. To get very appropriate category, the participants were expected to improve the ability of the components of speed, accuracy, and reaction speed to be more effective and efficient. Further research was expected to do a motion analysis using video recordings high speed camera on the frontal and sagittal angles.

The working space of small motor stators is narrow, and most of them are manual winding. It is difficult to guarantee the uniform arrangement of enameled wires by multi-wire winding. To solve these problems, a three-phase parallel equivalent multi-wire winding robot is proposed to achieve large output torque of the motor. Firstly, according to the equivalent model, the structure of the large arm, small arm and manipulator is designed to determine the motion model of the winding robot. Euler's kinematics theory is used to analyze the change of the working position of the arm, and the rotation matrix of the arm and the constraint equation of the motion vector of each branch chain are established. The motion model of the arm and the manipulator are established using inverse kinematics and analytical analysis. The motion pose of each joint of the winding robot is studied to ensure that the robot realizes a three-phase parallel multi-wire winding motion. ADAMS software was used for kinematic simulation analysis of the winding robot. The displacement of the branch chain on the xyz axis was represented by the torque of the virtual motor to verify the correctness of the inverse kinematics solution and the closure condition of the manipulator block. Finally, the ROS simulation platform is built to simulate the joint motion planning of the winding robot to verify the multi-line parallel principle and the feasibility of the multi-line parallel winding hybrid robot. The research results of this paper provide a theoretical reference for multi-wire parallel winding equipment control.

IF=1.46; International audience; This paper describes a new approach to analyse the way both hands are placed in relation to the steering wheel. The study is based on a 2D-tracking task, in which the stimulus is a steering wheel angle signal recorded while driving on 7 road geometries in real situations at 30 km/h. Hand movements are measured using a 3D-motion capture system. Data analysis is based on the segmentation of the hand angular position using 8 fuzzy angle windows (labelled as approximately 0°, approximately 45°, etc.), when the hand rests on the steering wheel, one window, else. To obtain information about the coordination aspect, 9 × 9 bivariate windows are considered for each time sample (recorded at 25 Hz); then, the average membership values are computed for each individual driving situation. The individual membership value sets related to the road geometries are studied via Correspondence Analysis, allowing to displaying both the inter- and intra-individual differences and the most discriminating bivariate windows. The methodology with 9 × 9 windows is more complex but implies less information loss than alternative ones e.g. when the two hands are separately analysed, which constitutes 9 + 9 windows and contains no information about the coordination aspect.

In order to help badminton players make reasonable training plans and realize a comprehensive grasp of the training process, this paper mainly recognizes and perceives the posture of badminton athletes based on the method of moving edge calculation. Firstly, from the perspective of moving edge motion analysis, considering the vector field formed by moving edge vector as movable spatial distribution information, the spatial distribution model of moving edge field is realized. Secondly, while athletes interact with the computer through limb movement, the overall posture of athletes is divided into several parts, and each part is perceived separately. Finally, in the human posture evaluation module, an algorithm for human posture evaluation in the image pixel plane is proposed. Through comparative experiments, the motion recognition algorithm can effectively recognize the three typical swing movements of badminton players in the video and improve the overall performance of the existing recognition algorithms.

While gait termination is challenging for children with spastic cerebral palsy (CCP), few studies have quantitatively assessed this issue.What are the characteristics of center of mass (COM) and center of pressure (COP) displacement during gait termination in CCP, and how do they compare with those in children with typical development (CTD)?This cross-sectional study included 13 adults with typical development (19.85 ± 0.52 years), 12 CTD (10.41 ± 2.98 years), and 16 CCP (11.15 ± 2.71 years). Participants were instructed to immediately stop walking when a stop sign appeared on a screen, which was placed at the end of an 8-m walkway. COM and COP were determined via 3-dimensional motion analysis and force plate data. Differences between the groups were assessed using the two sample t-test or Wilcoxon rank sum test. The level of statistical significance was set at P0.05.The normalized time for stopping in CCP (4.556 ± 0.602) was higher than that in CTD (3.617 ± 0.545, P0.001). The normalized COP displacement (P0.001) and divergence between COM and COP (P0.001) in the mediolateral (ML) direction were significantly higher in CCP than CTD. However, the normalized divergence between COM and COP in the anteroposterior (AP) direction in CCP was lower than that in CTD (P = 0.034).The more minor divergence between COM and COP in the AP direction and the more significant COP displacement in the ML direction cause difficulty to exert braking force during gait termination. Thus, CCP require a longer time for gait termination. This finding may facilitate the development of interventions for improving gait in CCP.

Rotational deformities following intramedullary (IM) nailing of tibia has a reported incidence of as high as 20%. Common techniques to measure deformities following IM nailing of tibia are either based on clinical assessment, plain X-rays or Computed Tomography (CT) comparing the treated leg with the uninjured contralateral side. All these techniques are based on examiners manual calculation inherently subject to bias. Following our previous rigorous motion analysis and symmetry studies on hemi pelvises, femurs and orthopaedic implants, we aimed to introduce a novel fully digital technique to measure rotational deformities in the lower legs. Following formal institutional approval from the Imperial College, CT images of 10 pairs of human lower legs were retrieved. Images were anonymized and uploaded to a research server. Three dimensional CT images of the lower legs were bilaterally reconstructed. CT-based motion analysis (CTMA) was used and the mirrored images of the left side were merged with the right side proximally as stationary and distally as moving objects. Discrepancies in translation and rotation were automatically calculated. Our study population had a mean age of 54 ± 20 years. There were six males and four females. We observed a greater variation in translation (mm) of Centre of Mass (COM) in sagittal plane (95% CI − 2.959–.292) which was also presented as rotational difference alongside the antero-posterior direction or Y axis (95% CI .370–1.035). In other word the right lower legs in our study were more likely to be in varus compared to the left side. However, there were no statistically significant differences in coronal or axial planes. Using our proposed fully digital technique we found that lower legs of the human adults were symmetrical in axial and coronal plane. We found sagittal plane differences which need further addressing in future using bigger sample size. Our novel recommended technique is fully digital and commercially available. This new technique can be useful in clinical practice addressing rotational deformities following orthopaedic surgical intervention. This new technique can substitute the previously introduced techniques.

Background/objective: There is a lack of information about relationship between physical characteristics and biomechanics of the lower extremity during the squat. Additionally, studies did not examine sex-related differences. The purpose of this study was to investigate relationships between physical characteristics and biomechanics of the lower extremity during the squat, and to determine if any sex differences are present. Methods: Fifty three participants recruited (21.82 ± 2.3 years; 75.56 ± 14.98 kg; 171.57 ± 8.38 cm) performed three squats with 75% of one repetition maximum. Femur to tibia length ratio, hip and ankle joints’ flexibilities, and relative muscular strength were measured and used as physical characteristics. Net joint torques (NJT) and flexion angles of the lower extremity were extracted as dependent variables. Multiple regression (stepwise) analysis was conducted to examine the relationships with physical characteristics being factors. Pearson correlation coefficients were calculated to determine intercorrelations among the dependent variables. Results: Relative muscular strength was related to hip NJT and knee flexion angle, and hip flexibility was related to ankle dorsiflexion. Hip and knee NJT showed moderate correlations with the corresponding flexion angles (r = 0.48-0.53; p

Moreover backhand short serve is an important element of the main character in badminton, where not many people can maximize the potential and limits of each athlete, such as power, speed, accuracy, and motion efficiency. This study aims to determine the potential and weaknesses of short backhand serve in badminton through a kinematic analysis approach, with a sample of children aged 12-16 years PB Pendowo Semarang City. The method used quantitative with a descriptive analysis approach, and the analysis is assisted by using the Kinovea 0.9.4 series software. The sampling technique used is purposive sampling with two criteria; age (12-16 years old) and participation in a Semarang city-level tournament. The results showed that the PB Pendowo Semarang City athletes in the implementation phase are in the "Appropriate" category, with a percentage of 66.6%. The instruments used in this data collection are observation and documentation. Several factors that influence the level of conformity are muscle mass, arm length and height, and training intensity. This research can still be developed in future research by discussing more specific things, such as focusing on active wrists and, more specifically, explain about flick movement in the wrist motion. Additional supporting literacy in the backhand short serve analysis could help the athletes and coaches to reach effective movement to get points using the backhand short of serving as the first attack., Apalagi servis pendek backhand merupakan elemen penting dari karakter utama dalam bulu tangkis, di mana tidak banyak orang yang bisa memaksimalkan potensi dan batasan masing-masing atlet, seperti tenaga, kecepatan, akurasi, dan efisiensi gerak. Penelitian ini bertujuan untuk mengetahui potensi dan kelemahan short backhand serve pada bulutangkis melalui pendekatan analisis kinematik, dengan sampel anak usia 12-16 tahun PB Pendowo Kota Semarang. Metode yang digunakan kuantitatif dengan pendekatan analisis deskriptif, dan analisisnya dibantu dengan menggunakan software Kinovea seri 0.9.4. Teknik pengambilan sampel yang digunakan adalah purposive sampling dengan dua kriteria; usia (12-16 tahun) dan keikutsertaan dalam turnamen tingkat kota Semarang. Hasil penelitian menunjukkan bahwa atlet PB Pendowo Kota Semarang pada tahap pelaksanaan berada pada kategori "Sesuai", dengan persentase sebesar 66,6%. Instrumen yang digunakan dalam pengumpulan data ini adalah observasi dan dokumentasi. Beberapa faktor yang mempengaruhi tingkat konformitas adalah massa otot, panjang dan tinggi lengan, serta intensitas latihan. Penelitian ini masih dapat dikembangkan dalam penelitian selanjutnya dengan membahas hal-hal yang lebih spesifik, seperti berfokus pada pergelangan tangan aktif dan, lebih khusus lagi, menjelaskan tentang gerakan jentikan dalam gerakan pergelangan tangan. Literasi pendukung tambahan dalam analisis servis pendek backhand dapat membantu para atlet dan pelatih untuk mencapai gerakan yang efektif untuk mendapatkan poin menggunakan backhand short dari servis sebagai serangan pertama.

BACKGROUND: Marker-based motion capture recordings of human body segments are often affected by soft tissue artifact (STA). The undesired and uncontrolled motion of the skin may introduce errors in the estimation of motion and position of body segments and, consequently, in the calculation of the relative functional quantities. METHODS: This study exploited a recently published dataset consisting of six adult subjects that underwent a total knee arthroplasty. The subject performed squat tasks while the motion was concurrently recorded by passive markers attached to the skin of the lower limbs, an optoelectronic system, and a fluoroscope. The STA of shank and thigh was decomposed in local deformation and rigid motion. Additionally, we studied how the instantaneous helical axis (IHA) calculation is affected by STA. FINDINGS: The cluster most affected by STA rigid motion was the thigh. The largest estimated effects were about 7 deg. and about 20 mm. The largest effect of local deformation was about 25 mm, and it was observed on the thigh cluster. INTERPRETATION: The STA made the estimation of the IHA unreliable for both position and direction. The choice of the reference configuration influenced the results of the STA analysis. ispartof: MEDICAL ENGINEERING & PHYSICS vol:110 ispartof: location:England status: published

Despite the frequent use of orthopedic braces or spine stabilizers in diseases such as kyphosis, lordosis, and scoliosis, as well as in the case of injuries and rehabilitation after surgeries, there is no clear evidence of their proper stabilization of the spine while carrying out daily activities. This study sought to assess the spine’s mobility while wearing three different orthopedic braces while performing basic tasks. Ten healthy subjects were enrolled. Three Inertial Measurement Units (IMUs) were attached superficially along the spine at approximate levels: cervical (C7), between thoracic (T8) and lumbar (L3), and sacrum. The angle between sensors was monitored to provide data on the sagittal profile. In addition, the displacement of the spine’s longitudinal axis was measured (rotation). There are three types of orthopedic braces: the semi-rigid Hohmann corset, the Jewett brace, and the Thoracolumbar Fixed Spinal Orthosis (TLSO). Four tasks were monitored: standing, sitting, walking, and picking up an item from the floor with one hand. All braces provided a similar level of stability in both the sagittal plane and rotational axis while lifting an object. On the other hand, while walking and sitting, the TLSO was the only orthosis providing a statistically significant rigidity in the sagittal plane. When performing a more voluntary task, the measured rigidity of softer braces was significantly increased when compared with more involuntary tasks. A certain degree of motion restriction with spinal orthoses may come from the feedback pressure, which stimulates paraspinal muscles to contract and thus increases the overall rigidity of the trunk.

Monitoring disease progression in Parkinson’s disease is challenging. Postural transfers by sit-to-stand motions are adapted to trace the motor performance of subjects. Wearable sensors such as inertial measurement units allow for monitoring motion performance. We propose quantifying the sit-to-stand performance based on two scores compiling kinematics, dynamics, and energy-related variables. Three groups participated in this research: asymptomatic young participants (n = 33), senior asymptomatic participants (n = 17), and Parkinson’s patients (n = 20). An unsupervised classification was performed of the two scores to differentiate the three populations. We found a sensitivity of 0.4 and a specificity of 0.96 to distinguish Parkinson’s patients from asymptomatic subjects. In addition, seven Parkinson’s patients performed the sit-to-stand task “ON” and “OFF” medication, and we noted the scores improved with the patients’ medication states (MDS-UPDRS III scores). Our investigation revealed that Parkinson’s patients demonstrate a wide spectrum of mobility variations, and while one inertial measurement unit can quantify the sit-to-stand performance, differentiating between PD patients and healthy adults and distinguishing between “ON” and “OFF” periods in PD patients is still challenging.

For humans, the hands represent the most important medium of interaction with the environment. In fact, their sophisticated kinematic structure and perception abilities allow to hold objects, perform gestures and perceive contact forces. The development of tools capable of detecting this information has become increasingly important in recent years given the implications in various fields ranging from medicine to robotics.

The use of inertial and physiological sensors in a sport such as judo is scarce to date. The information provided by these sensors would allow practitioners to have a better understanding of sports performance, which is necessary for an accurate training prescription. The purpose of this study was to use inertial and physiological sensors in order to investigate the effect of a plyometric and high-intensity interval training (HIIT) training program on Special Judo Fitness Test (SJFT) performance and speed of execution of throws in young judokas. A total of 32 participants were divided into two groups: experimental and control. The intervention consisted of six sessions with a duration of 60 min for 3 weeks. Physiological sensors collected heart rate data to assess the Special Judo Fitness Test, and inertial sensors collected angular velocity. The results show a significant decrease in the SJFT index (Score pre: 22.27 ± 2.73; Score post: 19.65 ± 1.70; p ≤ 0.05; d = 0.61) and a significant increase in the angular velocity of the X-axis (Pre: 320.87 ± 51.15°/s; Post: 356.50 ± 40.47°/s; p ≤ 0.05; d = 0.45) and Y-axis (Pre: 259.40 ± 41.99°/s; Post: 288.02 ± 65.12°/s; p ≤ 0.05; d = 0.31) in the experimental group. In conclusion, this study demonstrates that using inertial and physiological sensors allowed us to analyze the effect that a high-intensity interval training program and plyometrics had on the performance of young judokas. Strength and conditioning coaches should consider these results because including plyometric training and HIIT in judokas’ workout programming can be especially positive for eliciting increases in performance. However, future training interventions should investigate the training adaptations to longer interventions.

Achieving mechanistic understanding of transport in complex environments such as inside cells or at polymer interfaces is challenging. We need better ways to image transport in 3-D and better single particle tracking algorithms to determine transport that are not systemically biased toward any classical motion model. Here we present an unbiased single particle tracking algorithm: Knowing Nothing Outside Tracking (KNOT). KNOT uses point clouds provided by iterative deconvolution to educate individual particle localizations and link particle positions between frames to achieve 2-D and 3-D tracking. Information from prior point clouds fuels an independent adaptive motion model for each particle to avoid global models that could introduce biases. KNOT competes with or surpasses other 2-D methods from the 2012 particle tracking challenge while accurately tracking adsorption dynamics of proteins on polymer surfaces and early endosome transport in live cells in 3-D. We apply KNOT to study 3-D endosome transport to reveal new physical insight into locally directed and diffusive transport in live cells. Our analysis demonstrates better accuracy in classifying local motion and its direction compared to previous methods, revealing intricate intracellular transport heterogeneities.

BACKGROUND An ankle-foot orthosis with an oil damper (AFO-OD) may improve kinetics and kinematics for efficient walking after stroke. Yet it is unknown whether hemiplegic walking behaves like "inverted-pendulum" gait and how it is modulated by using AFO-ODs for efficiency. OBJECTIVES This study examined whether the use of AFO-ODs improves the kinetics of total vertical ground reaction force (vGRF) and kinematics of vertical pelvic displacement (vPD) in different walking phases, and gait speed following stroke. Also, the relationship between those gait parameters was examined to assess efficient walking. STUDY DESIGN Observational study within subject. METHODS Eight participants with hemiplegia walked at self-selected speed without and with AFO-ODs over the walkway and gait speed was measured. Force plates were used to measure total vGRF during the double-limb support phase with the paretic leading limb and with the paretic trailing limb (DSPT). The vPD in the paretic and nonparetic stance phases was measured by a three-dimensional motion analysis system. RESULTS Without AFO-ODs, reduced total vGRF during DSPT was related to greater vPD in the subsequent nonparetic stance. Using AFO-ODs significantly increased gait speed and total vGRF during double-limb support phase with the paretic leading limb and during DSPT, which were significantly correlated. Vertical pelvic displacement in the nonparetic stance was higher than the paretic stance in both conditions. CONCLUSIONS Decreased total vGRF during DSPT was compensated by excessive vPD in the nonparetic stance phase without AFO-ODs, indicating inefficient walking. However, the use of AFO-ODs improved the kinetic energy of total vGRF during the double-limb support phase, contributing to efficient walking. CLINICAL RELEVANCE STATEMENT The AFO-ODs can be used to improve kinetic energy and to modulate functions in the weight transition during the double-limb support phase, with faster walking speed. Thus, AFO-ODs can be considered to be therapeutic AFOs to acquire efficient walking performance in poststroke rehabilitation.