Biomechanics

The knowledge of the onset and cessation timing of the paraspinal muscles that surround the lumbar spine is an important area of research for the understanding of low back pain. This study examined the timing of the erector spinae and external oblique muscle activity in a group of golfers with and without low back pain. The study compared the results of surface electromyography measurements for two groups of golfers. Twelve male golfers who had reported a mild or greater level of pain in the lower back that was experienced while playing golf were examined. A further fifteen male golfers who had reported no history of lower back pain in the previous 12 months were recruited as controls. The results showed that the low back pain golfers switched-on their erector spinae muscle significantly in advance of the start of the backswing. This finding was not evident in the group who did not have low back pain symptoms. Low back pain golfers therefore, may use the erector spinae muscle as a primary spinal stabiliser instead of the stronger deeper muscles such as transversus abdominis and multifidus. These results may have important implications for conditioning programmes for golfers with low back pain.

There are several pathologies related to the patellofemoral joint, in which the patellofemoral syndrome is one af the most common and challenging to treat. The patellofemoral syndrome results from a malalignment of the knee extenso r mechanism. The purpose af our study was to describe and compare EMG responses of the vastus medialis and vastus lateralis muscles while walking up and down stairs and other clinical and functional responses in PFS subjects before and afier a physical therapy intervention. Eleven subjects were studied and divided in two groups: six subjects with clinically diagnosed patellofemoral syndrome and five healthy control subjects. Subjects were evaluated by a functional and biomechanical evaluation protocol: postural evaluation, pain and knee function evaluation, and electromyographic activity of vastus medialis and lateralis muscles while walking up and down a staircase. Results showed higher efficiency of the vastus medialis muscle in carrying out eccentric exercises and increased musc1e activity in both the vastus medialis and vastus lateralis muscles while c1imbing stairs after physical therapy treatment. We were able to identify an improvement in postural alignment of lower Ihl1b muscles and knee functionality among patellofemoral syndrome group subjects afier treatment.

Anterior cruciate ligament (ACL) deficient and reconstructed knees display altered biomechanics during gait. Identifying significant gait changes is important for understanding normal and ACL function and is typically performed by statistical approaches. This paper focuses on the development of an explainable machine learning (ML) empowered methodology to: (i) identify important gait kinematic, kinetic parameters and quantify their contribution in the diagnosis of ACL injury and (ii) investigate the differences in sagittal plane kinematics and kinetics of the gait cycle between ACL deficient, ACL reconstructed and healthy individuals. For this aim, an extensive experimental setup was designed in which three-dimensional ground reaction forces and sagittal plane kinematic as well as kinetic parameters were collected from 151 subjects. The effectiveness of the proposed methodology was evaluated using a comparative analysis with eight well-known classifiers. Support Vector Machines were...

The purpose of this study was to determine whether the training responses observed with low-load resistance exercise to volitional fatigue translates into significant muscle hypertrophy, and compare that response to high-load resistance training. Nine previously untrained men (aged 25 [SD 3] years at the beginning of the study, standing height 1.73 [SD 0.07] m, body mass 68.9 [SD 8.1] kg) completed 6 weeks of high load-resistance training (HL-RT) (75% of one repetition maximal [1RM], 3-sets, 3x/wk) followed by 12 months of detraining. Following this, subjects completed 6 weeks of low load-resistance training (LL-RT) to volitional fatigue (30% 1 RM, 4 sets, 3x/wk). Increases (p < 0.05) in magnetic resonance imaging-measured triceps brachii and pectoralis major muscle cross-sectional areas were similar for both HL-RT (11.9% and 17.6%, respectively) and LL-RT (9.8% and 21.1%, respectively). In addition, both groups increased (p < 0.05) 1RM and maximal elbow extension strength following training; however, the percent increases in 1RM (8.6% vs. 21.0%) and elbow extension strength (6.5% vs. 13.9%) were significantly (p < 0.05) lower with LL-RT. Both protocols elicited similar increases in muscle cross-sectional area, however differences were observed in strength. An explanation of the smaller relative increases in strength may be due to the fact that detraining after HL-RT did not cause strength values to return to baseline levels thereby producing smaller changes in strength. In addition, the results may also suggest that the consistent practice of lifting a heavy load is necessary to maximize gains in muscular strength of the trained movement. These results demonstrate that significant muscle hypertrophy can occur without high-load resistance training and suggests that the focus on percentage of external load as the important deciding factor on muscle hypertrophy is too simplistic and inappropriate. Figure 1. Typical magnetic resonance imaging image showing transverse scan of the chest.

The main objective of this work is the evaluation, by means of the finite element method (FEM) of the mechanical stability and long-term microstructural modifications in bone induced to three different kinds of fractures of the distal femur by three types of implants: the Condyle Plate, the less invasive stabilization system plate (LISS) and the distal femur nail (DFN). The displacement and the stress distributions both in bone and implants and the internal bone remodelling process after fracture and fixation are obtained and analysed by computational simulation. The main conclusions of this work are that distal femoral fractures can be treated correctly with the Condyle Plate, the LISS plate and the DFN. The stresses both in LISS and DFN implant are high especially around the screws. When respect to remodelling, the LISS produces an important resorption in the fractured region, while the other two implants do not strongly modify bone tissue microstructure.

In this study Interlocking nails were used in order to fixate the canine femoral fractures and to examine the effects of the implants on fracture healing, clinically and radipgraphically in 19 dogs. The material of the study consisted 19 dogs of medium-large size, which were brought to Ankara University, Faculty of Veterinary Medicine, Department of Orthopedics and Traumatology because of injuries due to various trauma and consequent diaphyseal femur fractures clinically and radiologically. Following general anaesthesia, the broken extremity was operated, a total of 20 interlocking pins of different sizes were placed. Among the pins used with an appropriate diameter and length, 10 were 8-199 mm, 4 were 8-185 mm, 2 were 8-172, 1 was 8-165, 2 were 6-172 mm and another was 6-160 mm, respectively. In order to lock these pins 46, 3.5 mm diameter screws, with different length were used. It was observed that 1 screw in proximal and 1 screw in distal region, didn't hold in the holes of the pins. Statical nailing was performed in all cases but one. Cases were clinically examined for weight bearing and extremity usage and radiologically, the callus tissue development was monitored. As a result; the idea was that interlocking nailing technique was on alternative to plates by creating enough rigidity, to fixate 1/3 diaphyseal femoral fractures in medium and medium-large breed dogs. Köpeklerde Femur Kırıklarında Interlocking Çivisi Uygulamaları; Ondokuz Olguda Klinik Deneyim ve Sonuçlar Özet Bu çalışmada köpeklerde femur kırıklarında interlocking çivileme sistemi kullanılarak implantın kırık iyileşmesine olan etkileri ve kullanım kolaylığı klinik ve radyolojik olarak değerlendirilmiştir. Çalışmanın materyalini Ankara Üniversitesi Veteriner Fakültesi Ortopedi ve Travmatoloji Kliniği'ne getirilen ve yapılan klinik-radyolojik kontrollerde femur kırığı saptanan 19 adet orta-büyük ırktan köpek oluşturmuştur. Hastaların kırıkları genel anestezileri ve rutin operatif hazırlıkları tamamlandıktan sonra, toplam 20 adet, uygun çap ve uzunlukta interlocking çivileri ile onarılmıştır. Çalışmada 10 adet 8 mm çap 199 mm uzunlukta, 4 adet 8 mm çap 185 mm uzunlukta, 2 adet 8 mm çap 172 mm uzunlukta, adet 8 mm çap 165 mm uzunlukta, 2 adet 6 mm çap 172 mm uzunlukta ve bir adet 6 mm çap 160 mm uzunlukta çivi kullanılmıştır. Bu çiviler toplam 46 adet 3.5 mm çaplı farklı uzunluklarda vidalar ile sabitlenmiştir. 44 vida yerini bulurken 1 distal ve 1 proksimal vida çivi üzerindeki deliği tutmamış ve korteks ile çivi arasından geçmiştir. Bir olgu hariç tüm olgularda statik çivileme yapılmıştır. Olgular postoperatif dönemde klinik ve radyolojik olarak takip edilerek ekstremitelerini kullanma durumları ile kallus formasyonu izlenmiştir. Sonuç olarak interlocking çivileme sisteminin femur diafiz kırıklarında plaklara alternatif olarak kullanılabilecek gerekli stabiliteyi sağlayan bir alternatif olabileceği kanısına varılmıştır.

Combinatorial strategy has been used in therapeutic angiogenesis in animal models of peripheral arterial disease (PAD) and coronary artery disease for decades. Previous studies have shown that basic fibroblast growth factor (FGF-2) and platelet-derived growth factor BB (PDGF-BB) proteins together establish functional and stable vascular networks on mouse corneal and also in animal model of hindlimb ischemia. However, the short half life of protein by single injection is not sufficient to achieve effective dosage, repeated and prolonged injection causes systemic toxicity. Here we study the synergistic effects of FGF-2 and PDGF-BB by intramuscular injection of naked plasmid DNA on therapeutic angiogenesis in rabbit model of hindlimb ischemia. We found that transient delivery of FGF-2 and PDGF-BB naked DNA together resulted in greater increases in capillary growth, collateral formation and popliteal blood flow compared with control and single gene delivery. Our data provided novel evidence of beneficial effects of DNA-based FGF-2 and PDFG-BB on muscle repair after ischemic injury. These findings reveal an alternative therapeutic approach in the treatment of ischemic diseases and even in muscular disorders.

Plantar pressure assessment is a tool useful for study of the gait cycle. In this study, we present a means of assessing the gait cycle using a temporal analysis of plantar pressures and lower-leg muscle activities. Plantar pressures and surface electromyography (EMG) of the tibialis anterior (TA) and medial gastrocnemius (MG) muscles were recorded as 19 men walked on a treadmill at seven speeds between 0.45 and 1.79 m/s. A typical 'heel strike to toe off' gait pattern was observed. Speed had minimal effects on the shapes of the muscle EMG root-mean-square-and plantar pressure-time curves except for the pressure-time curves in the heel and midfoot. A linear relationship was found between speed and peak pressures in the heel, medial forefoot, and toes; pressures in these regions increased by 91-289% going from 0.45 to 1.79 m/s. The temporal pressure changes in the forefoot and toes were paralleled by changes in MG muscle activity (i.e., cross-correlations of 0.90); TA muscle activity was not cross-correlated with the temporal pressure patterns in any region. However, the peak values of TA muscle activity were found to be highly correlated across speeds with peak pressures in the heel and toes (i.e., r 0.98); similar high correlations were found between peak values of MG muscle activity and heel pressure. In summary, these data collected on able-bodied persons during motorized treadmill walking can be useful for comparison to those of patients undergoing treadmill evaluations for atypical gait cycle patterns and for tracking the progress of patients during gait rehabilitation.

This dissertation would not have been possible without the contributions and support of many people along the way. I would like to take the opportunity to recognize the following mentors, colleagues, friends, and family for their efforts on my behalf. First, I would like to thank my committee members for their roles in shaping my graduate career, and ultimately this work. Many thanks to my advisor and committee chair, Dr. Ben Auerbach, who supported my vision for this project from its inception and always had excellent ideas for its improvement. His anatomy and biomechanics teachings also greatly influenced my research. I would also like to thank Dr. Andrew Kramer for his insightful comments and advice, which enhanced this research, as well as his unwavering support over the years. I will strive for a teaching style as effective as his. I extend my sincere gratitude to Dr. Richard Jantz for his encouragement of me and my project along the way. His statistical advice and courses on secular change and human variation have also significantly (pun intended) impacted my dissertation research. In addition, I sincerely thank Dr. David Bassett for applying his expertise to the review of my work. Furthermore, his enthusiasm and positivity will not be forgotten. The influence of each of my committee members on the development of my dissertation is clear, and I am exceedingly appreciative of their guidance. There are many researchers and colleagues who were not on my committee that also had integral roles in making this project possible. I especially would like to thank Dr. Natalie Shirley for providing me with access to CT scans, teaching me various imaging software, and funding me with a research assistantship. None of this would have been feasible without her mentorship iv and support. I also want to thank Dr. Dawnie Steadman and Dr. Lee Jantz for their permissions to access the William M. Bass Donated Collection and its associated resources. I am privileged to have made use of such a valuable resource. I also appreciate Dr. Emam Elhak Abdel-Fatah for his help in understanding various imaging software and processing, and Dr. Graciela Cabana for facilitating my language exam. I am truly indebted to my family and friends for their support in this endeavor. I came to Knoxville without knowing a soul, and since then have forged several lifelong friendships. I would like to thank some of the best friends and brightest colleagues I know: Beatrix Dudzik,

Post-activation potentiation (PAP) has been shown to increase force generation due to prior muscular activity which can acutely improve strength and power performance. Typically, heavy-loaded bench press has been used as a conditioning contraction for a PAP stimulus. However, a heavy loaded weight exercise is frequently not available prior to performance, due to varying factors such as regulations or practicality for athletes. The aim of this study was to examine whether lower load exercises can cause an induction of PAP.
Fourteen male, competitive university level athletes (mean ± SD: age, 21.9 ± 2.2 years; height 1.8 ± 0.05 m; body mass 76.3 ± 8.2 kg) performed an explosive bench press (with 50% 1RM load) immediately prior to one of four conditioning contractions; 2 x 45 seconds of suspended chest press, 3 x 8 repetitions of resistance band lying bench press, 3 x 10 repetitions of push-ups, or no conditioning contractions. Rest between all sets was 30 seconds and the conditioning contraction order was randomised. The explosive bench press was performed again at 2, 4, 6 and 8 minutes after the conditioning contraction. Peak power (Ppeak), peak force (Fpeak), peak velocity (Vpeak), rate of force development (RFD) and a percentage of EMG from the Pectoralis Major, Anterior Deltoid and Triceps Brachii were recorded for all trials and a maximum voluntary contraction (MVC). Normality of data was checked using the Shapiro-Wilks test and confirmed for Ppeak, Fpeak, Vpeak, and EMG triceps but not for RFD, EMG chest and EMG shoulder. Repeated measures ANOVA with Bonferroni correction was used to check for differences between normally distributed data, while a Friedman’s test was used to check for differences in RFD, EMG chest and EMG shoulder. A Wilcoxon Signed Ranks test was used to analyse the difference found in the data for EMG shoulder. 
The results showed no significant difference between the variables for any of the conditioning contractions between baseline, 2, 4, 6 and 8 minutes. Similarly, there was no significant difference in any variables was shown between conditioning contractions at baseline, 2, 4, 6 and 8 minutes. Whereas, EMG shoulder showed a difference in the RB intervention between trials 1 and 2 (Z = -2.480, p = 0.013), 1 and 4 (Z = -2.480, p = 0.013), 1 and 5 (Z = -2.103, p=  0.035) and trials 2 and 3 (Z = -2.103, p = 0.035), with a difference also found in the PU intervention, between trials 2 and 3 (Z = -2.229, p = 0.026) and trials 2 and 4 (Z = -2.103, p = 0.035).
The findings suggest that PAP was not induced by any of the conditioning contractions used in this study. As the design employed in the current study has been used previously showing higher weighted exercises inducing PAP, we conclude that a) the loading used in the current study was insufficient to induce PAP, b) there is a ‘load threshold’ below which PAP cannot be induced, c) the stimulus from the EMG was not high enough to induce PAP, and d) muscle excitation is not a contributing mechanism to an induction of PAP.

Quantitative ultrasound has attracted significant interest in the evaluation of bone fracture healing. Animal and clinical studies have demonstrated that the propagation velocity across fractured bones can be used as an indicator of healing. Researchers have recently employed computational methods for modeling wave propagation in bones, aiming to gain insight into the underlying mechanisms of wave propagation and to further enhance the monitoring capabilities of ultrasound. In this paper, we review the relevant literature and present the current status of knowledge.

Determining the epithelium's contribution to corneal biomechanics is important for the predictive numerical simulation of corneal biomechanical behaviour in which the cornea's five main layers are represented separately. Twenty-four corneal buttons were tested under posterior inflation conditions while monitoring their behaviour using non-contact methods. The corneas were divided into two groups of 12; one with and one without the epithelium. Control of specimen hydration, temperature and pressure application rate, and limiting the programme to specimens within a small age range resulted in a narrow scatter of test results. On average, intact specimens were able to carry slightly more pressure at the same deformation, and experienced less average stress for the same strain, compared with specimens without the epithelium. These results indicated that the stiffness of the epithelium was considerably lower than that of the stroma, and might therefore be ignored in numerical simulation studies.

The main purpose of the present study was to investigate the kinematics and kinetics of successful versus unsuccessful basketball free throw shots. Six professional basketball players (age= 23±2.09 years members of Iranian premier basketball league participat in test. Kinematics of arm motion during basketball free throws were recorded by two Casio zr200 camera in frequency of 240 Hz. Wilcoxon test was used for significant differences between successful versus unsuccessful free throws (p ≤ 0/05). Angular velocity of the wrist was found to be significantly higher in successful versus unsuccessful shots at the time of ball release (p ≤ 0/028). Wrist (p ≤ 0/008) and shoulder (p ≤ 0/023) joints were found to have significantly more flexion in successful versus unsuccessful shots while elbow (p ≤ 0/002) remained significantly less flexed in successful shots. Angular displacement of wrist (p ≤ 0/034) and elbow (p ≤ 0/004) was shown to be significantly greater in successful versus unsuccessful shots. Integrated EMG of Anterior Deltoid (AD), Triceps Brachii (TB) and Flexor Carpi Radialis (FCR) muscles was more in successful free throw versus unsuccessful free throw, but the only significant difference was observed in the Integrated EMG of the Triceps Brachii muscle (p ≤ 0/034). In summery, increasing the wrist angular velocity and activity of triceps brachii muscle affected successful free throws.

In this pilot study, we point out potential differences between calcaneal trabecular microarchitecture in humans and nonhuman large apes, such as increased degree of anisotropy, reduced bone volume fraction, and very stereotypical orientation of the trabeculae. Even though sample size does not permit us to investigate the issue statistically, the observed differences between humans and other hominoids warrants further in-depth investigation. We also show that some in Wiley InterScience (www.interscience.wiley.com).

Muscle Boost X Switch out your office chair for an exercise ball. Sitting on one of these balls helps you tone your abs and core muscles as you constantly use them to maintain posture and balance. You can also use the stability ball for performing other exercises, such as squats or yoga poses, in your office.

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Current studies on pole-vaulting focus mostly on energy transfer data [Ekevad, M., Lundberg, B., 1995. Simulation of ''smart'' pole .] and often fail to take into account the actions exerted on the pole [Arampatzis, . Effect of the pole-human body interaction on pole-vaulting performance. Journal of Biomechanics 37, 1353-1360]. The present study integrates the 3D kinematics data of the athlete but also the actions measured at the end of the pole in the planting box and on the track during the last stride before take-off. It proposes a mechanical model allowing determination of the pole-vaulter's actions on the pole. The model is based on a global mechanical approach. The pole-vaulter's action on his upper and lower hand is concentrated on one middle point to solve the dynamics problem. The model was applied to seven experienced pole-vaulters. The force and the moment exerted on the pole by the pole-vaulter during the last stride before take off and during jump stage, were calculated. This analysis of the compressive force and bending moment for seven pole-vaulters helps to highlight the impact of the moment in the performance. The conclusion is confirmed by an additional comparative study carried out on two polevaulters, with comparable morphologies and performing with the same pole. r

In presence of aortic stenosis, a jet is produced downstream of the aortic valve annulus during systole. The vena contracta corresponds to the location where the cross-sectional area of the flow jet is minimal. The maximal transvalvular pressure gradient (TPG(max)) is the difference between the static pressure in the left ventricle and that in the vena contracta. TPG(max) is highly time-dependent over systole and is known to depend upon the transvalvular flow rate, the effective orifice area (EOA) of the aortic valve and the cross-sectional area of the left ventricular outflow tract. However, it is still unclear how these parameters modify the TPG(max) waveform. We thus derived an explicit analytical model to describe the instantaneous TPG(max) across the aortic valve during systole. This theoretical model was validated with in vivo experiments obtained in 19 pigs with supravalvular aortic stenosis. Instantaneous TPG(max) was measured by catheter and its waveform was compared with the one determined from the derived equation. Our results showed a very good concordance between the measured and predicted instantaneous TPG(max). Total relative error and mean absolute error were on average 9.4+/-4.9% and 2.1+/-1.1 mmHg, respectively. The analytical model proposed and validated in this study provides new insight into the behaviour of the TPG(max) and thus of the aortic pressure at the level of vena contracta. Because the static pressure at the coronary inlet is similar to that at the vena contracta, the proposed equation will permit to further examine the impact of aortic stenosis on coronary blood flow.

Currently, cerebrovascular diseases are one of the main health problems. Part of the patient’s rehabilitation process, affected by this disease, is manually performed by a physiotherapist, which, due to physical exhaustion, could affect the performance of patient recovery. In this paper is proposed a robotic exoskeleton for upper limb rehabilitation, which enables assist or supports the therapist’s work. In the first stage, the exoskeleton is controlled passively through programmed commands and routines. Later, a second stage is proposed for biofeedback control system using the exoskeleton and signals acquired through bioinstrumentation equipment. This system will allows the acquisition of the surface electromyography signals (sEMG), as well as proprioceptive information for signal processing and movement’s intention detection of upper limb. As results, are presented the implementation of robotic arm commanded passively and the bioinstrumentation equipment is presented. In the rehabilitation field, this assistive technology will enable to medical staff, to contribute to recovery and welfare of the patient, affected by some kind of muscular dysfunction, with major effectiveness.

The purpose of this study was to investigate the effect of tissue hydration on the structural properties of human patellar tendon. Specimens were subjected to a load relaxation experiment prior to being stretched to failure. The experiments indicated that tendons relaxed faster in hypotonic solutions when compared to hypertonic solutions. At a strain rate of 50% s-r the structural stiffness was significantly higher while immersed in a hypotonic versus hypertonic solution. No difference in tensile stiffness was documented between baths for 0.5% s-l. Tendons immersed in the hypotonic solution were significantly stiffer for 50% s-r against 0.5% s-r. The results indicate that the structural properties of human patellar tendon are more sensitive to time when the tissues are fully hydrated.

Whole body vibration (WBV) is a promising tool for counteracting bone loss. Most WBV studies on animals have been performed at acceleration &lt;1g and frequency between 30 and 90Hz. Such WBV conditions trigger bone growth in osteopenia models, but not in healthy animals. In order to test the ability of WBV to promote osteogenesis in young animals, we exposed seven-week-old male mice to vibration at 90Hz and 2g peak acceleration for 15min/day, 5 days/week. We examined the effects on skeletal tissues with micro-computed tomography and histology. We also quantified bone vascularization and mechanosensitive osteocyte proteins, sclerostin and DMP1. Three weeks of WBV resulted in an increase of femur cortical thickness (+5%) and area (+6%), associated with a 25% decrease of sclerostin expression, and 35% increase of DMP1 expression in cortical osteocytes. Mass-structural parameters of trabecular bone were unaltered in femur or vertebra, while osteoclastic parameters and bone formation rat...

Biodegradable polymer scaffolds have played a significant role in wide range of tissue engineering application such as bone scaffolds since the last decade. The aim of this article is to provide the comprehensive overview of biocompatible and biodegradable polymer materials and composite materials with their advantages and drawbacks in the application of biomaterial scaffolds, furthermore the properties and degradation criteria of the biomaterials are discussed in this review.

A computer-based data acquisition system has been developed to analyze the long term performance of polymer insulators using a fog chamber. The leakage currents flowing through the insulators under test are sensed, conditioned, digitized, processed, displayed, and finally stored for firther analysis.' Based on the requirements of the application, a comparative study of different data acquisition packages was conducted to select the appropriate software. Virtual instrumentation software, DASYLab, was determined to be the most suitable option for this application. An icon-based program has been developed to classib the leakage current pulse counts using bins, and to compute cumulative charge, and maximum and minimum current pulse values. It also provides real-time display and Fourier analysis of the acquired data. The data is reduced and stored in files on a hard disk for post-acquisition analysis.

An automatic Uni-or Multi-modal Inteligent Seizure Acquisition (UISA/MISA) system is highly applicable for onset detection of epileptic seizures based on motion data. The modalities used are surface electromyography (sEMG), acceleration (ACC) and angular velocity (ANG). The new proposed automatic algorithm on motion data is extracting features as "log-sum" measures of discrete wavelet components. Classification into the two groups "seizure" versus "nonseizure" is made based on the support vector machine (SVM) algorithm. The algorithm performs with a sensitivity of 91-100%, a median latency of 1 second and a specificity of 100% on multi-modal data from five healthy subjects simulating seizures. The uni-modal algorithm based on sEMG data from the subjects and patients performs satisfactorily in some cases. As expected, our results clearly show superiority of the multimodal approach, as compared with the uni-modal one.

The velocity by which the disturbance travels through the medium is the wave velocity. Pulse wave velocity is one of the main parameters in hemodynamics. The study of wave propagation through the fluid-fill elastic tube is of great importance for the proper biophysical understanding of the nature of blood flow through of cardiovascular system. The effect of viscosity on the pulse wave velocity is generally ignored. In this paper we present the results of experimental measurements of pulse wave velocity (PWV) of compression and expansion waves in elastic tube. The solutions with different density and viscosity were used in the experiment. Biophysical model of the circulatory flow is designed to perform measurements. Experimental results show that the PWV of the expansion waves is higher than the compression waves during the same experimental conditions. It was found that the change in viscosity causes a change of PWV for both waves. We found a relationship between PWV, fluid density ...

Decreased bone mineral density (BMD) in astronauts returning from long-duration spaceflight missions has been well documented, but the altered mechanical loading environment experienced by the musculoskeletal system, which may contribute to these changes, has not been well characterized. The current study describes the loading environment of the lower extremity (LE) during typical days on the International Space Station (ISS) compared to similar data for the same individuals living on Earth. Data from in-shoe force measurements are also used as input to the enhanced daily load stimulus (EDLS) model to determine the mechanical ''dose'' experienced by the musculoskeletal system and to associate this dose with changes in BMD.

In a chamber of the heart, large-scale vortices are shown to exist as the result of the dynamic blood flow and unique morphological changes of the chamber wall. As the cardiovascular flow varies over a cardiac cycle, there is a need for a robust quantification method to analyze its vorticity and circulation. We attempt to measure vortex characteristics by means of two-dimensional vorticity maps and vortex circulation. First, we develop vortex component analysis by segmenting the vortices using an data clustering algorithm before histograms of their vorticity distribution are generated. The next stage is to generate the statistics of the vorticity maps for each phase of the cardiac cycle to allow analysis of the flow. This is followed by evaluating the circulation of each segmented vortex. The proposed approach is dedicated to examining vortices within the human heart chamber. The vorticity field can indicate the strength and number of large-scale vortices in the chamber. We provide the results of the flow analysis after vorticity map segmentation and the statistical properties that characterize the vorticity components. The success of the cardiac measurement and analysis is illustrated by a case study of the right atrium. Our investigation shows that it is possible to utilize a data clustering algorithm to segment vortices after vorticity mapping, and that the vorticity and circulation analysis of a chamber vorticity can provide new insights into the blood flow within the cardiovascular structure.

Patient motion during brain SPECT studies can c l e m resolution and introduce distortion. We have developed a correction method which incorporates a motion tracking system to monitor the position and orientation of the patient's head during acquisition. Correction is achieved by spatially repositioning projections according to measured head movements and reconstructing these projections with a fully three-dimensional (3D) algorithm. The method has been evaluated in SPECT studies of the Hoffman 3D brain phantom performed on a triple head camera with fan beam collimation. Movements were applied to the phantom and recorded by a head tracker during SPECT acquisition. Fully 3D reconstruction was performed using the motion data provided by the tracker. Correction accuracy was assessed by comparing the corrected and uncorrected studies with a motion free study, visually and by calculating mean squared error (MSE). In all studies, motion correction reduced distortion and improved MSE by a factor of 2 or more. We conclude that this method can compensate for head motion under clinical SPECT imaging conditions. 0-7803-5021 -9/99/$10.00 0 1999 IEEE.

Deep tissue injury (DTI) is a severe pressure ulcer that results from sustained deformation of muscle tissue overlying bony prominences. In order to understand the etiology of DTI, it is essential to determine the tolerance of muscle cells to large mechanical strains. In this study, a new experimental method of determining the time-dependent critical compressive strains for necrotic cell death ðE c zz ðtÞÞ in a planar tissue-engineered construct under static loading was developed. A half-spherical indentor is used to induce a nonuniform, concentric distribution of strains in the construct, and E c zz ðtÞ is calculated from the radius of the damage region in the construct versus time. The method was employed to obtain E c zz ðtÞ for bio-artificial muscles (BAMs) cultured from C2C12 murine cells, as a model system for DTI. Specifically, propidium iodine was used to fluorescently stain the development of necrosis in BAMs subjected to strains up to 80%. Two groups of BAMs were tested at an extracellular pH of 7.4 (n ¼ 10) and pH 6.5 (n ¼ 5). The lowest strain levels causing cell death in the BAMs were determined every 15 min, during 285-min-long trials, from confocal microscopy fluorescent images of the size of the damage regions. The experimental E c zz ðtÞ data fitted a decreasing single-step sigmoid of the Boltzmann type. Analysis of the parameters of this sigmoid function indicated a 95% likelihood that cells could tolerate engineering strains below 65% for 1 h, whereas the cells could endure strains below 40% over a 285 min trial period. The decrease in endurance of the cells to compressive strains occurred between 1-3 h post-loading. The method developed in this paper is generic and suitable for studying E zz c (t) in virtually any planar tissue-engineered construct. The specific E c zz ðtÞ curve obtained herein is necessary for extrapolating biological damage from muscle-strain data in biomechanical studies of pressure ulcers and DTI. r

Biological vessels are characterized by their substantial compliance and low friction that present a major challenge for crawling robots for minimally invasive medical procedures. Quite a number of studies considered the design and construction of crawling robots; however, very few focused on the interaction between the robots and the flexible environment. In a previous study, we derived the analytical efficiency of worm locomotion as a function of the number of cells, friction coefficients, normal forces, and local (contact) tangential compliance. In this paper, we introduce the structural effects of environment compliance, generalize our previous analysis to include dynamic and static coefficients of friction, determine the conditions of locomotion as function of the external resisting forces, and experimentally validate our previous and newly obtained theoretical results. Our experimental setup consists of worm robot prototypes, flexible interfaces with known compliance and a Vicon motion capture system to measure the robot positioning. Separate experiments were conducted to measure the tangential compliance of the contact interface that is required for computing the analytical efficiency. The validation experiments were performed for both types of compliant conditions, local and structural, and the results are shown to be in clear match with the theoretical predictions. Specifically, the convergence of the tangential deflections to an arithmetic series and the partial and overall loss of locomotion verify the theoretical predictions.

In order to create a hemodynamic environment that can simulate the physiological condition of arteries, an in vitro experiment apparatus was designed whose key modules were compliance chamber and after-load. These two modules were developed based on the theories of hemodynamics. Both the normal and shear stress to which endothelial cells are exposed can be controlled with these modules, thus facilitating the research of endothelial cells subjected to stresses. Ó

The purpose of this study was to examine whether the wrist lagging angle in golf down swing had an impact on both driving distance and driving accuracy for NCAA Division I female golfers. Seven female golfers all freshmen from a mid-Atlantic region NCAA Division I school volunteered to participate in the research with consent from their head coach. A Full Swing Golf Simulator was used to obtain variables and Dartfish was utilized to measure the wrist lagging angles in the down swing. Multivariate General Linear Regression (MGLR) was conducted to explore the possible cause and effect relationship and to identify a correlation matrix among driving distance, accuracy and wrist angle and other variables. The results indicated that only wrist angle and club head speed were significant in predicting both driving distance and accuracy. Other variables such as club head speed, smash effect, side spin and back spin were also found significant in the MGLR model (p < .01). Future studies should focus on identifying how wrist lagging angle affect male golfers and how does it affect irons in both distance and accuracy.

Two noninvasive measurement techniques wen used to monitor activity-induced changes in skeletal muscle in humans. Phosphorus magnetic lcsonancc spectroscopy (P-MRS) was used to meastt~c changes in cturgy metabolism by measuring the ratio of inorganic phosphate to phosphocmtine (Pi&Q) during steady level work in the wrist flexor muscles in a 30 cm bate. I .9 Teisa magnet, and the rate of PCr recovery from c~ercise in the calf muscles in a 76 cm bate, I .8 Tesla magnet. Near red spectroscopy (NRS) was used to measure changes in oxygen saturation of hemoglobin and myoglobin during and after exercise. Fourteen days of wrist flexion exercise tesulted in significant improvement in muscle metabolism as measund by MRS. This improvement disqpcarcd after 35 days of inactivity. Indications of muscle stnss during training such as muscle sotcness and decrrwd maximum strength were associated with increases in rrsting Pi/PO. A similar training protocol using plantar flexion exercise ~sultedinanimprovedrateofPCr~synthesis.whichnturnedtoconttolvrlucs42dr~rfterariningrtopped.NRS measurements of the wrist flexor muscles during a ramp exercise protocol demonstrated a decnase in the oxygen saturation of hemoglobin-myoglobin from 60% at rest to 15% at the highest work levels. The half time of recovery of oxygen saturation was faster than that of PCr in both young and old subjects. suppotting the hypothesis that oxygen delivery is not rate limiting in submaximal exercise in healthy individuals.

An important goal in rehabilitation engineering is to develop technology that allows individuals with severe motor impairment to practice arm movement without continuous supervision from a rehabilitation therapist. This paper describes the development of such a system, called Therapy WREX or ("T-WREX"). The system consists of an orthosis that assists in arm movement across a large workspace, a grip sensor that detects hand grip pressure, and software that simulates functional activities. The arm orthosis is an instrumented, adult-sized version of the Wilmington Robotic Exoskeleton (WREX), which is a five degrees-of-freedom mechanism that passively counterbalances the weight of the arm using elastic bands. After providing a detailed design description of T-WREX, this paper describes two pilot studies of the system's capabilities. The first study demonstrated that individuals with chronic stroke whose arm function is compromised in a normal gravity environment can perform reaching and drawing movements while using T-WREX. The second study demonstrated that exercising the affected arm of five people with chronic stroke with T-WREX over an eight week period improved unassisted movement ability (mean change in Fugl-Meyer score was 5 points 2 SD; mean change in range of motion of reaching was 10%, 0 001). These results demonstrate the feasibility of automating upper-extremity rehabilitation therapy for people with severe stroke using passive gravity assistance, a grip sensor, and simple virtual reality software.

Torticollis is a visible medical condition. Your child’s head constantly tilts to one side. Torticollis means twisted neck in Latin.  The condition is also called wry neck or twisted neck. Torticollis can be congenital or acquired. Congenital muscular torticollis is a condition affecting babies. Most parents don’t notice the defect until the baby is several weeks old. Toricollosis is a rare medical condition in India.

Fractures of metatarsal are most common fractures in children foot. Most common causes are direct injuries to the fore foot.Here we present a case of non union metatarsal shaft fracture with 90degrees deformity treated by open reduction and internal fixation with locking recon plate in a single sitting.