Body Lower Limb Research Articles

The Effects of 12 Weeks In-Water Training in Stroke Kinematics, Dry-Land Power, and Swimming Sprints Performance in Master Swimmers

Background: Master swimming is becoming increasingly popular, but research related to the training process and its effect on this population is scarce. The aim of this study was to investigate the effects of 12 weeks in-water training in stroke kinematics, dry-land power, and swimming sprints performance in master swimmers, and the relationships between these variables in this sports population. Methods: 15 healthy and physically active male master swimmers (age 32.3 ± 5.1 years, height 1.81 ± 0.04 m, body mass 77.0 ± 6.5 kg, training experience of 11 ± 4 years and average swimming training volume ~2.5 km/day, 3 times a week) participated in the study. Previously and after the intervention program, entirely water-based, swimmers were tested in a dry-land environment to assess their upper and lower body limbs (UL and LL) strength through power measurements, namely countermovement jumps (CMJ), seated 3 kg medicine ball throwing (MBT) and maximal isometric strength with handgrip (HG). In-water 50 m maximal front crawl swimming test was also completed. Swimming performance at 15, 25, and 50 m (T15, T25, and T50) was determined, and the associated stroke kinematics. During the intervention program period, swimming training comprised three sessions per week (7.5 ± 0.9 km per microcycle), with low- to high-intensity aerobic and anaerobic swimming series and technical drills. Results: T25 significantly decreased after 12 weeks of training (18.82 ± 2.92 vs. 18.60 ± 2.87 sec, p = 0.02), the same was observed in the case of T50 (40.36 ± 7.54 vs. 38.32 ± 6.41 sec, p = 0.00). Changes in stroke rate (SR), stroke length (SL) and stroke index (SI) in swimming performance at 15 m were not observed, contrarily to 25 and 50 m, where SL and SI significantly increased. MBT and HG improved, but not CMJ, and improvements in T15, T25 and T50 were mostly related to kinematic proficiency improvement. Conclusions: 12 weeks of in-water training in master swimmers significantly enhance performance time in 25 and 50 m front crawl swimming. SL and SI are also improved and are the variables that most influence T15, T25 and T50 when compared to SR and dry-land power variables. Centering the training process not only in in-water tasks in master swimmers seem to be of relevant interest since age influences stroke kinematic and power variables.

Bifurcated Arterial Circulation for Hybrid Aortic Reconstruction: A Novel Technique.

Hybrid aortic procedures present many new challenges to the management of cardiopulmonary bypass (CPB). Reoperation or previous thoracic endovascular aortic repair (TEVAR) can further complicate these procedures, increasing the need for flexibility within the CPB system to execute multiple perfusion strategies as cases dictate. This technique describes the use of a bifurcated arterial circulation to provide both cerebral and lower body perfusion during a redo hybrid aortic arch reconstruction. The arterial line was divided into upper and lower body limbs, and connected to an 8-mm Dacron graft to the axillary artery, as well as a percutaneous 16-Fr. OptiSite femoral arterial cannula respectively. A 25-Fr. multi-stage femoral venous cannula was placed percutaneously as well. CPB was initiated utilizing both arterial cannulas with near-infrared spectroscopy and electroencephalogram to monitor the adequacy of cerebral perfusion. Moderate hypothermia of 26°C was induced and a CODA balloon (Cook Medical, Bloomington, IN) was deployed to occlude the proximal limb of a thoracic endovascular repair (TEVAR) graft; the common trunk of the debranched arch vessels was clamped proximally, allowing for simultaneous upper and lower body perfusion. Upon completion of the distal arch, the CODA balloon was removed and total body perfusion was reinitiated via central cannulation utilizing a sidearm on the arch graft.

Short-Term Effects of the Repeated Exposure to Trip-like Perturbations on Inter-Segment Coordination during Walking: An UCM Analysis

The minimum toe clearance (MTC) results from the coordination of all bilateral lower limb body segments, i.e., a redundant kinematic chain. We tested the hypothesis that repeated exposure to trip-like perturbations induces a more effective covariation of limb segments during steady walking, in accordance with the uncontrolled manifold (UCM) theory, to minimize the MTC across strides. Twelve healthy young adults (mean age 26.2 ± 3.3 years) were enrolled. The experimental protocol consisted of three identical trials, each involving three phases carried outin succession: steady walking (baseline), managing trip-like perturbations, and steady walking (post-perturbation). Lower limb kinematics collected during both steady walking phases wereanalyzed in the framework of the UCM theory to test the hypothesis that the reduced MTC variability following the perturbation can occur, in conjunction with more effective organization of the redundant lower limb segments. Results revealed that, after the perturbation, the synergy underlying lower limb coordination becomes stronger. Accordingly, the short-term effects of the repeated exposure to perturbations modify the organization of the redundant lower limb-related movements. In addition, results confirm that the UCM theory is a promising tool for exploring the effectiveness of interventions aimed at purposely modifying motor behaviors.

An anthropometry survey of Bangladeshi university students

ABSTRACT The study aimed to establish an anthropometric dataset of Bangladeshi male and female university students. Voluntary participants included 400 students aged 17 to 23 from eight divisional areas of Bangladesh. From the sample population, 37 body parameters were measured, documented, and examined. Kolmogorov–Smirnov, ANOVA and t-tests were used to correlate intra-populations (Bangladeshi male and female) and inter-populations (Bangladeshi and other nationalities) anthropometric data. When comparing the anthropometry of male and female populations, significant differences were observed in upper body limbs rather than lower body limbs. The variability in anthropometric measurements among the four age groups of females was found to be greater than that of males. Patterns of difference between Bangladeshi and other country populations were identified and discussed. Finally, some implementation methods of the collected anthropometric data, and their differences were briefly discussed in designing furniture (as product), scissor (as tool), helmet (as equipment), and control system (as workplace).

Efficiency of deep neural networks for joint angle modeling in digital gait assessment

Reliability and user compliance of the applied sensor system are two key issues of digital healthcare and biomedical informatics. For gait assessment applications, accurate joint angle measurements are important. Inertial measurement units (IMUs) have been used in a variety of applications and can also provide significant information on gait kinematics. However, the nonlinear mechanism of human locomotion results in moderate estimation accuracy of the gait kinematics and thus joint angles. To develop “digital twins” as a digital counterpart of body lower limb joint angles, three-dimensional gait kinematic data were collected. This work investigates the estimation accuracy of different neural networks in modeling lower body joint angles in the sagittal plane using the kinematic records of a single IMU attached to the foot. The evaluation results based on the root mean square error (RMSE) show that long short-term memory (LSTM) networks deliver superior performance in nonlinear modeling of the lower limb joint angles compared to other machine learning (ML) approaches. Accordingly, deep learning based on the LSTM architecture is a promising approach in modeling of gait kinematics using a single IMU, and thus can reduce the required physical IMUs attached on the subject and improve the practical application of the sensor system.

KINEMATICS AND INJURY MECHANISM OF CYCLIST LOWER LIMB IN VEHICLE-TO-BICYCLE COLLISIONS

Accident data show that lower limb is one of the most frequently injured body parts for cyclists in vehicle collisions. However, studies of cyclist lower limb injuries and protection are still sparse. Therefore, the purpose of this study is to investigate the kinematics and injury mechanism of cyclist lower limb in vehicle-to-bicycle collisions considering different impact boundary conditions. To achieve this, the finite element (FE) modeling approach and an FE human body lower limb model with detailed muscles were employed, and impact boundary conditions with different vehicle front-end shapes and cycling postures were considered. Predictions of lower limb kinematics, knee ligament elongation and bending moment of upper and lower leg were used for analysis. The simulation results show that cycling posture has a significant influence on cyclist lower limb kinematics and injury risk, lateral bending toward the direction of vehicle or vehicle moving combining with lateral shearing is the main mechanism for cyclist knee ligament injuries, and injuries to long bones of cyclist leg in vehicle impacts could form lateral bending at both directions. The findings suggest that the influence of cycling posture and distinct difference in injury mechanism between cyclist and pedestrian should be considered in the assessment of vehicle safety design for cyclist lower limb protection.

Spatial distribution of cutaneous anthrax in western Iran from 2009 to 2016: Geographic information system mapping for predicting risk of anthrax outbreaks

Objective: To explore the spatial accumulation of diseases and their aggravating factors are essential in all public health. This study attempts to use geographic information system (GIS) to provide more information about the incidence and future of anthrax. Methods: Patients were diagnosed with anthrax in Kurdistan Province from 2009 to 2016. Data was then exported into ArcGIS software version 9 and the required layers for years and areas were added.Final map for each year was drawn up, pointing out the hot spots and predicting its future pattern. Results: Most cases were reported in females (57 cases, 54.80 %), and the lower body limbs were most affected (63 cases, 60.57%). The highest numbers of incidences were related to the cities of Marivan, Saqez and Divandareh, with more concentration in the central parts of the province, rather than borderline areas. The highest percentage of the probable incidence of the disease was in Sanandaj (57.74%) with a potential susceptible area of 1 729.12 km2 and then in Saqez (54.36%) with a potential area of 2 422.4 km2. Conclusions: A vast area of Kurdistan Province is high risk for new cases of anthrax. Therefore, it is important to scale up the surveillance system in the province.

Changes in muscle mass of lower limbs body components among the judokas at the age of 7-9

Changes in muscle mass of lower limbs body components among the judokas at the age of 7-9

Ergonomic Evaluation of Workload in Imbalanced Lower Limbs Postures

Objective: The purpose of this study is to compare the workload level at each lower limbs posture and suggest the ergonomic workstation guideline for working period by evaluating the imbalanced lower limbs postures from the physiological and psychophysical points of view. Background: Many workers like welders are working in various imbalanced lower limbs postures either due to the narrow working conditions or other environmental conditions. Method: Ten male subjects participated in this experiment. Subjects were asked to maintain 3 different lower limbs postures(standing, squatting and bending) with 3 different working conditions(balanced floor with no scaffold, imbalanced floor with 10㎝ height of scaffold, and imbalanced floor with 20㎝ height of scaffold). EMG data for the 4 muscle groups(Retus Femoris, Vastus Lateralis, Tibialis Anterior, Gastrocnemius) from each lower limbs posture were collected for 20 seconds every 2 minutes during the 8 minutes sustaining task. Subjects were also asked to report their discomfort ratings of body parts such as waist, upper legs, lower legs, and ankle. Results: The ANOVA results showed that the EMG root mean square(RMS) values and the discomfort ratings(CR-10 Rating Scale) were significantly affected by lower limbs postures and working time(p＜0.05). The correlation was analyzed between the EMG data and the discomfort ratings. Also, prediction models for the discomfort rating for each posture were developed using physical condition, working time, and scaffold height. Conclusion: We strongly recommend that one should not work more than 6 minutes in a standing or squatting postures and should not work more than 4 minutes in a bending posture. Application: The results of this study could be used to design and assess working environments and methods. Furthermore, these results could be used to suggest ergonomic guidelines for the lower limbs postures such as squatting and bending in the working fields in order to prevent fatigue and pain in the lower limbs body.

Virtual Reconstruction of Long Bone Fracture in Car-to-pedestrian Collisions Using Multi-body System and Finite Element Method

Lower limb injures are frequently observed in passenger car traffic accidents. Previous studies of the injuries focus on long bone fractures by using either cadaver component tests or simulations of the long bone kinematics, which lack in-depth study on the fractures in stress analysis. This paper aims to investigate lower limb impact biomechanics in real-world car to pedestrian accidents and to predict fractures of long bones in term of stress parameter for femur, tibia, and fibula. For the above purposes, a 3D finite element (FE) model of human body lower limb (HBM-LL) is developed based on human anatomy. The model consists of the pelvis, femur, tibia, fibula, patella, foot bones, primary tendons, knee joint capsule, meniscus, and ligaments. The FE model is validated by comparing the results from a lateral impact between simulations and tests with cadaver lower limb specimens. Two real-world accidents are selected from an in-depth accident database with detailed information about the accident scene, car impact speed, damage to the car, and pedestrian injuries. Multi-body system (MBS) models are used to reconstruct the kinematics of the pedestrians in the two accidents and the impact conditions are calculated for initial impact velocity and orientations of the car and pedestrian during the collision. The FE model is used to perform injury reconstructions and predict the fractures by using physical parameters, such as von Mises stress of long bones. The calculated failure level of the long bones is correlated with the injury outcomes observed from the two accident cases. The reconstruction result shows that the HBM-LL FE model has acceptable biofidelity and can be applied to predict the risk of long bone fractures. This study provides an efficient methodology to investigate the long bone fracture suffered from vehicle traffic collisions.