Tendinous Tissue Research Articles

Differences in in vivo muscle fascicle and tendinous tissue behavior between the ankle plantarflexors during running.

The primary human ankle plantarflexors, soleus (SO), medial gastrocnemius (MG), and lateral gastrocnemius (LG) are typically regarded as synergists and play a critical role in running. However, due to differences in muscle-tendon architecture and joint articulation, the muscle fascicles and tendinous tissue of the plantarflexors may exhibit differences in their behavior and interactions during running. We combined in vivo dynamic ultrasound measurements with inverse dynamics analyses to identify and explain differences in muscle fascicle, muscle-tendon unit, and tendinous tissue behavior of the primary ankle plantarflexors across a range of steady-state running speeds. Consistent with their role as a force generator, the muscle fascicles of the uniarticular SO shortened less rapidly than the fascicles of the MG during early stance. Furthermore, the MG and LG exhibited delays in tendon recoil during the stance phase, reflecting their ability to transfer power and work between the knee and ankle via tendon stretch and storage of elastic strain energy. Our findings add to the growing body of evidence surrounding the distinct mechanistic functions of uni- and biarticular muscles during dynamic movements.

Maximal shortening velocity during plantar flexion: Effects of pre-activity and initial stretching state.

We investigated the effects of the initial length of the muscle-tendon unit (MTU) and muscle pre-activation on muscle-tendon interactions during plantarflexion performed at maximal velocity. Ultrasound images of gastrocnemius medialis were obtained on 11 participants in three conditions: (a) active plantarflexion performed at maximal velocity from three increasingly stretched positions (10°, 20°, and 30° dorsiflexion), (b) passive plantarflexion induced by a quick release of the ankle joint from the same three positions, and (c) pre-activation, which consisted of a maximal isometric contraction of the plantarflexors at 10° of dorsiflexion followed by a quick release of ankle joint. During the active condition at maximal velocity, initial MTU stretch positively influenced ankle joint velocity (+15.3%) and tendinous tissues shortening velocity (+37.6%) but not the shortening velocity peak value reached by muscle fascicle. The muscle fascicle was shortened during the passive condition; however, its shortening velocity never exceeded peak velocity measured in the active condition. Muscle pre-activation resulted in a considerable increase in ankle joint (+114.7%) and tendinous tissues velocities (+239.1%), although we observed a decrease in muscle fascicle shortening velocity. During active plantarflexion at maximal velocity, initial MTU length positively influences ankle joint velocity by increasing the contribution of tendinous tissues. Although greater initial stretch of the plantarflexors (ie, 30° dorsiflexion) increased the passive velocity of the fascicle during initial movement, its peak velocity was not affected. As muscle pre-activation prevented reaching the maximal muscle fascicle shortening velocity, this condition should be used to characterize tendinous tissues rather than muscle contractile properties.

Tendinous tissue properties after short‐ and long‐term functional overload: Differences between controls, 12 weeks and 4 years of resistance training

The potential for tendinous tissues to adapt to functional overload, especially after several years of exposure to heavy-resistance training, is largely unexplored. This study compared the morphological and mechanical characteristics of the patellar tendon and knee extensor tendon-aponeurosis complex between young men exposed to long-term (4years; n=16), short-term (12weeks; n=15) and no (untrained controls; n=39) functional overload in the form of heavy-resistance training. Patellar tendon cross-sectional area, vastus lateralis aponeurosis area and quadriceps femoris volume, plus patellar tendon stiffness and Young's modulus, and tendon-aponeurosis complex stiffness, were quantified with MRI, dynamometry and ultrasonography. As expected, long-term trained had greater muscle strength and volume (+58% and +56% vs untrained, both P<.001), as well as a greater aponeurosis area (+17% vs untrained, P<.01), but tendon cross-sectional area (mean and regional) was not different between groups. Only long-term trained had reduced patellar tendon elongation/strain over the whole force/stress range, whilst both short-term and long-term overload groups had similarly greater stiffness/Young's modulus at high force/stress (short-term +25/22%, and long-term +17/23% vs untrained; all P<.05). Tendon-aponeurosis complex stiffness was not different between groups (ANOVA, P=.149). Despite large differences in muscle strength and size, years of resistance training did not induce tendon hypertrophy. Both short-term and long-term overload demonstrated similar increases in high-force mechanical and material stiffness, but reduced elongation/strain over the whole force/stress range occurred only after years of overload, indicating a force/strain specific time-course to these adaptations.

Automatic Myotendinous Junction Tracking in Ultrasound Images with Phase-Based Segmentation.

Displacement of the myotendinous junction (MTJ) obtained by ultrasound imaging is crucial to quantify the interactive length changes of muscles and tendons for understanding the mechanics and pathological conditions of the muscle-tendon unit during motion. However, the lack of a reliable automatic measurement method restricts its application in human motion analysis. This paper presents an automated measurement of MTJ displacement using prior knowledge on tendinous tissues and MTJ, precluding the influence of nontendinous components on the estimation of MTJ displacement. It is based on the perception of tendinous features from musculoskeletal ultrasound images using Radon transform and thresholding methods, with information about the symmetric measures obtained from phase congruency. The displacement of MTJ is achieved by tracking manually marked points on tendinous tissues with the Lucas-Kanade optical flow algorithm applied over the segmented MTJ region. The performance of this method was evaluated on ultrasound images of the gastrocnemius obtained from 10 healthy subjects (26.0 ± 2.9 years of age). Waveform similarity between the manual and automatic measurements was assessed by calculating the overall similarity with the coefficient of multiple correlation (CMC). In vivo experiments demonstrated that MTJ tracking with the proposed method (CMC = 0.97 ± 0.02) was more consistent with the manual measurements than existing optical flow tracking methods (CMC = 0.79 ± 0.11). This study demonstrated that the proposed method was robust to the interference of nontendinous components, resulting in a more reliable measurement of MTJ displacement, which may facilitate further research and applications related to the architectural change of muscles and tendons.

Maintenance of Tendon Stem/Progenitor Cells in Culture.

Tendon stem/progenitor cells (TSCs) are tendon-specific adult stem cells, which play crucial roles in tendon homeostasis, repair or regeneration once tendons are injured. Additionally, their pathological role in the development of tendinopathy in response to excessive mechanical loading placed on the tendon is also implicated. Similar to other adult stem cells, TSCs also exhibit universal characteristics of stem cells including colony formation in culture, self-renewal and multidifferentiation potential. Nevertheless, once TSCs are isolated from tendinous tissues and cultured in vitro, they may quickly lose stemness by undergoing differentiation. To maintain and prolong the stemness of TSCs in culture, we have developed two effective methods, namely culturing TSCs in hypoxic condition, or in growth media supplemented with low levels of PGE2. Here we present these methods in detail, along with the detailed description of the procedures to isolate TSCs from tendon samples and to culture them in vitro.

The slack test does not assess maximal shortening velocity of muscle fascicles in humans.

The application of a series of extremely high accelerative motor-driven quick releases while muscles contract isometrically (i.e. slack test) has been proposed to assess unloaded velocity in human muscle. This study aimed to measure gastrocnemius medialis fascicle shortening velocity (VF) and tendinous tissue shortening velocity during motor-driven quick releases performed at various activation levels to assess the applicability of the slack test in humans. Gastrocnemius medialis peak VF and joint velocity recorded from 25 participants using high frame rate ultrasound during quick releases (at activation levels from 0% to 60% of maximal voluntary isometric torque) and during fast contractions without external load (ballistic condition) were compared. Unloaded joint velocity calculated using the slack test method increased whereas VF decreased with muscle activation level (P≤0.03). Passive and low-level quick releases elicited higher VF values (≥41.8±10.7 cm s-1) compared with the ballistic condition (36.3±8.7 cm s-1), while quick releases applied at 60% of maximal voluntary isometric torque produced the lowest VF These findings suggest that initial fascicle length, complex fascicle-tendon interactions, unloading reflex and motor-driven movement pattern strongly influence and limit the shortening velocity achieved during the slack test. Furthermore, VF elicited by quick releases is likely to reflect substantial contributions of passive processes. Therefore, the slack test is not appropriate to assess maximal muscle shortening velocity in vivo.

Subtalar Joint Pronation and Energy Absorption Requirements During Walking are Related to Tibialis Posterior Tendinous Tissue Strain

During human walking, the tibialis posterior (TP) tendon absorbs energy in early stance as the subtalar joint (STJ) pronates. However, it remains unclear whether an increase in energy absorption between individuals, possibly a result of larger STJ pronation displacement, is fulfilled by greater magnitudes of TP tendon or muscle fascicle strain. By collecting direct measurements of muscle fascicle length (ultrasound), MTU length (3D motion capture and musculoskeletal modelling), and TP muscle activation (intramuscular electromyography) we endeavoured to illustrate that the TP tendinous tissue fulfils the requirements for energy absorption at the STJ as a result of an increase in muscle force production. While a significant relationship between TP tendon strain, energy absorption at the STJ (R2 = 0.53, P = < 0.01) and STJ pronation (R2 = 0.53, P = < 0.01) was evident, we failed to find any significant associations between tendon strain and surrogate measure of TP muscle force (TP muscle activation together with ankle and subtalar joint moments). These results suggest that TP tendon compliance may explain the variance in pronation and energy absorption at the STJ. Therefore, as the tendinous tissue of the TP is accountable for the absorption of energy at the STJ it may be predisposed to strain-induced injury.

Imbalances in the Development of Muscle and Tendon as Risk Factor for Tendinopathies in Youth Athletes: A Review of Current Evidence and Concepts of Prevention.

Tendons feature the crucial role to transmit the forces exerted by the muscles to the skeleton. Thus, an increase of the force generating capacity of a muscle needs to go in line with a corresponding modulation of the mechanical properties of the associated tendon to avoid potential harm to the integrity of the tendinous tissue. However, as summarized in the present narrative review, muscle and tendon differ with regard to both the time course of adaptation to mechanical loading as well as the responsiveness to certain types of mechanical stimulation. Plyometric loading, for example, seems to be a more potent stimulus for muscle compared to tendon adaptation. In growing athletes, the increased levels of circulating sex hormones might additionally augment an imbalanced development of muscle strength and tendon mechanical properties, which could potentially relate to the increasing incidence of tendon overload injuries that has been indicated for adolescence. In fact, increased tendon stress and strain due to a non-uniform musculotendinous development has been observed recently in adolescent volleyball athletes, a high-risk group for tendinopathy. These findings highlight the importance to deepen the current understanding of the interaction of loading and maturation and demonstrate the need for the development of preventive strategies. Therefore, this review concludes with an evidence-based concept for a specific loading program for increasing tendon stiffness, which could be implemented in the training regimen of young athletes at risk for tendinopathy. This program incorporates five sets of four contractions with an intensity of 85–90% of the isometric voluntary maximum and a movement/contraction duration that provides 3 s of high magnitude tendon strain.

Effect of muscle force during stretch on eccentric contraction-induced muscle damage

Introduction: Eccentric contraction-induced muscle damage (ECIMD) typically results in a deficit in force and increase in optimum muscle fibre length. These effects can be exaggerated by higher muscle force, larger muscle stretch amplitudes, and longer initial muscle lengths prior to stretch. However, in vivo, where muscle-tendon unit length is constrained, muscle fibres operate at shorter lengths when generating higher forces as a result of the stretch of elastic tendinous tissues. Accordingly, under conditions of increased loading, shorter relative muscle lengths at the initiation of stretch may partially offset the effect of higher muscle force during stretch on ECIMD. The aim of this study was to study the effect of muscle force during stretch on quantitative and qualitative indicators of ECIMD.

Effect of a prehop on the muscle-tendon interaction during vertical jumps.

Many movements use stretch-shortening cycles of a muscle-tendon unit (MTU) for storing and releasing elastic energy. The required stretching of medial gastrocnemius (MG) tendinous tissue during jumps, however, requires large length changes of the muscle fascicles because of the lack of MTU length changes. This has a negative impact on the force-generating capacity of the muscle fascicles. The purpose of this study was to induce a MG MTU stretch before shortening by adding a prehop to the squat jump. Eleven well-trained athletes specialized in jumping performed a prehop squat jump (PHSJ) and a standard squat jump (SSJ). Kinematic data were collected using a 3D motion capture system and were used in a musculoskeletal model to calculate MTU lengths. B-mode ultrasonography of the MG was used to measure fascicle length and pennation angle during the jumps. By combining the muscle-tendon unit lengths, fascicle lengths, and pennation angles, the stretch and recoil of the series elastic element of MG were calculated using a simple geometric muscle-tendon model. Our results show less length changes of the muscle fascicles during the upward motion and lower maximal shortening velocities, increasing the moment-generating capacity of the plantar flexors, reflected in the higher ankle joint moment in the PHSJ compared with the SSJ. Although muscle-tendon interaction during the PHSJ was more optimal, athletes were not able to increase their jump height compared with the SSJ. NEW & NOTEWORTHY This is the first study that aimed to improve the muscle-tendon interaction in squat jumping. We effectively introduced a stretch to the medial gastrocnemius muscle-tendon unit resulting in lower maximal shortening velocities and thus an increase in the plantar flexor force-generating capacity, reflected in the higher ankle joint moment in the prehop squat jump compared with the standard squat jump. Here, we demonstrate an effective method for mechanical optimization of the muscle-tendon interaction in the medial gastrocnemius during squat jumping.

Factors contributing to lower metabolic demand of eccentric compared with concentric cycling.

This study compared muscle-tendon behavior, muscle oxygenation, and muscle activity between eccentric and concentric cycling exercise at the same work output to investigate why metabolic demand is lower during eccentric cycling than with concentric cycling. Eleven untrained men (27.1 ± 7.0 y) performed concentric cycling (CONC) and eccentric cycling (ECC) for 10 min (60 rpm) at 65% of the maximal concentric cycling power output (191 ± 45 W) 4 wk apart. During cycling, oxygen consumption (V̇o2), heart rate (HR), vastus lateralis (VL) tissue total hemoglobin (tHb), and oxygenation index (TOI) were recorded, and muscle-tendon behavior was assessed using ultrasonography. The surface electromyogram (EMG) was recorded from VL, vastus medialis (VM), rectus femoris (RF), and biceps femoris (BF) muscles, and cycling torque and knee joint angle during each revolution were also recorded. Average V̇o2 (-65 ± 7%) and HR (-35 ± 9%) were lower and average TOI was greater (16 ± 1%) during ECC than CONC, but tHb was similar between bouts. Positive and negative cycling peak crank torques were greater (32 ± 21 and 48 ± 24%, respectively) during ECC than CONC, but muscle-tendon unit and fascicle and tendinous tissue length changes during pedal revolutions were similar between CONC and ECC. VL, VM, RF, and BF peak EMG amplitudes were smaller (24 ± 15, 22 ± 18, 16 ± 17, and 18 ± 9%, respectively) during ECC than CONC. These results suggest that the lower metabolic cost of eccentric compared with concentric cycling was due mainly to a lower level of muscle activation per torque output.NEW & NOTEWORTHY This study shows that lower oxygen consumption of eccentric compared with concentric cycling at the same workload is explained by lower muscle activity of agonist and antagonist muscles during eccentric compared with during concentric cycling.

Scleraxis is required for maturation of tissue domains for proper integration of the musculoskeletal system

Scleraxis (Scx) is a basic helix-loop-helix transcription factor that is expressed persistently in tendons/ligaments, but transiently in entheseal cartilage. In this study, we generated a novel ScxCre knock-in (KI) allele, by in-frame replacement of most of Scx exon 1 with Cre recombinase (Cre), to drive Cre expression using Scx promoter and to inactivate the endogenous Scx. Reflecting the intensity and duration of endogenous expression, Cre-mediated excision occurs in tendinous and ligamentous tissues persistently expressing Scx. Expression of tenomodulin, a marker of mature tenocytes and ligamentocytes, was almost absent in tendons and ligaments of ScxCre/Cre KI mice lacking Scx to indicate defective maturation. In homozygotes, the transiently Scx-expressing entheseal regions such as the rib cage, patella cartilage, and calcaneus were small and defective and cartilaginous tuberosity was missing. Decreased Sox9 expression and phosphorylation of Smad1/5 and Smad3 were also observed in the developing entheseal cartilage, patella, and deltoid tuberosity of ScxCre/Cre KI mice. These results highlighted the functional importance of both transient and persistent expression domains of Scx for proper integration of the musculoskeletal components.

Aggressive fibromatosis of head and neck: Considerations on the optimal treatment method on the basis of case report

Abstract Introduction The term fibromatosis refers to proliferation of fibrous tissue in the form of irregular nodules or soft tissue sarcoma. It is characterized by local malignancy with tendency to recurrence, significant hypertrophy of the mature connective tissue and lack of the ability to form distant metastases. Pathological lesions originate from fascial, muscle and tendinous tissue. Aim The aim of this work is to analyze the efficacy and safety of the selected methods of treatment of aggressive fibromatosis on the basis of the presented case. Case study A five-year-old boy was admitted to the Department of Otolaryngology of the Provincial Specialist Children’s Hospital in Olsztyn due to right sided cervical mass. Histological examination of biopsy material revealed aggressive fibromatosis. The child was previously treated for two years with systemic chemotherapy with methotrexate, vinblastine, vincristine, imatinib and tamoxifen with no improvement. Surgical tumor removal was performed on February 14, 2014. During the 18-month observation period no signs of tumor recurrence were observed. Results and discussion In the treatment of aggressive fibromatosis various therapeutic methods are used, including radiotherapy, chemotherapy and surgery. The effects of chemotherapy and radiotherapy are frequently unsatisfying. These methods are associated with numerous complications and side effects, thus mode of treatment should be considered individually for each patient. In case of the presented patient surgical tumor removal was the best and the most effective treatment method. Conclusions Surgery should be a treatment of choice, whereas chemotherapy and radiotherapy should be considered as alternative or complementary methods in the treatment of aggressive fibromatosis.

Muscle fascicle shortening behaviour of vastus lateralis during a maximal force-velocity test.

Muscle fascicles-tendon interactions are the main determinant in production of high joint velocity. Currently, no study has investigated the muscle fascicles behaviour of knee extensor muscles until the highest reachable velocity (e.g., unloaded knee extension). We aimed to track the changes in vastus lateralis fascicles length during knee extensions to quantify muscle fascicles and tendinous tissues contributions to muscle-tendon unit shortening and to determine maximal muscle fascicles shortening velocity. Fifteen participants performed isokinetic and isoinertial knee extensions, and ultrafast ultrasound imaging was used to observe the vastus lateralis fascicles from low to very high joint velocity. The muscle fascicles shortening velocity increased linearly with the increase in knee joint velocity up to the maximal joint velocity (mean R 2=0.93±0.08). Muscle fascicles contribution to muscle-tendon unit shortening velocity was almost constant regardless of the condition (83±23%). Using Hill's equation, the maximal velocity of knee joint and muscle fascicles was determined at 1000±489°s-1 and 5.1±2.0 L0s-1 (47.4±18.7cms-1), respectively. Contribution of muscle fascicles to the muscle-tendon unit shortening velocity was much higher for the vastus lateralis in this study compared to the gastrocnemius medialis in two previous studies. Moreover, this contribution of muscle fascicles shortening velocity was constant whatever the velocity condition, even at the highest reachable velocity. Thus, the vastus lateralis fascicles shortening velocity increases linearly with the knee joint velocity until high velocities and its behaviour strongly accorded with the classical Hill's force-velocity relationship.

Slower Walking Speed in Older Men Improves Triceps Surae Force Generation Ability.

Older adults walk slower than young adults, but it is not known why. Previous research suggests that ankle plantarflexors may have a crucial role in the reduction of walking speed. The purpose of this study was to investigate age-related differences in triceps surae muscle-tendon function during walking to further investigate the role of plantarflexors in the age-related reduction of walking speed. Medial gastrocnemius and soleus muscle fascicle lengths were measured using ultrasound imaging during walking from 13 young (25 ± 4 yr) men at preferred walking speed and from 13 older (73 ± 5 yr) men at preferred speed and at the young men's preferred speed. Muscle-tendon unit lengths were calculated from joint kinematics, and tendinous tissue lengths were calculated by subtracting muscle lengths from muscle-tendon unit lengths. In addition, ground reaction forces and electromyographic activity of medial gastrocnemius and soleus were measured. In both medial gastrocnemius and soleus, it was observed that at preferred walking speed, older men used a narrower muscle fascicle operating range and lower shortening velocity at the estimated time of triceps surae peak force generation compared with young men. Fascicles also accounted for a lower proportion of muscle-tendon unit length changes during the stance phase in older compared with young men. Significant differences in triceps surae muscle function were not observed between age groups when compared at matched walking speed. In older men, walking at preferred speed allows triceps surae muscles to generate force with more favorable shortening velocity and to enhance use of tendinous tissue elasticity compared with walking at young men's preferred speed. The results suggest that older men may prefer slower walking speeds to compensate for decreased plantarflexor strength.

Differential expression of miRNAs in Osborne's ligament of cubital tunnel syndrome.

Cubital tunnel syndrome (CuTS) is the second most common peripheral nerve compression disease, however, the pathogenesis and pathology of CuTS remain to be fully elucidated. The aim of the present study was to compare the expression pattern of microRNAs (miRNAs) in pachyntic Osborne's ligament with that in control tendinous tissue, and select meaningful miRNAs for further investigation of the clinical pathological mechanism underlying CuTS. A microarray assay was performed to examine the expression profiles of miRNAs in the Osborne's ligament and control tendinous tissues. An online bioinformatics algorithms tool (miRWalk) was used to predict putative target genes for the deregulated miRNAs, and functional annotation was performed by Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Finally, the results of microarray were partially validated using reverse transcription-quantitative polymerase chain reaction analysis. The expression of total of 60 miRNAs were found to be significantly different between the pachyntic Osborne's ligament and control tendinous tissues. MiRWalk2.0 predicted 1,804 target genes for these miRNAs, and the GO functional analysis of the predicted genes suggested cellular mechanisms, including metabolic process, regulation of cell growth, cell cycle processes, cell division regulation, cellular metabolic process and signal transmission, were involved. Furthermore, KEGG pathway analysis revealed important pathways, including adherent junction, focal adhesion, lysine degradation, cell adhesion molecules and mitogen-activated protein kinase. Compared with the heathy tissue, Osborne's ligament tissue from patients with CuTS showed a markedly different miRNA expression profile, which suggested that miRNAs may be involved in the pathogenesis of CuTS.

The effect of platelet-rich plasma on Achilles tendon healing in a rabbit model

ObjectiveThe aim of the present study was to evaluate the effects of PRP on Achilles tendon healing in rabbits during the inflammatory, proliferative, and remodeling phases by histological examination and quantitative assessments. MethodsFifty mature male Japanese albino rabbits with severed Achilles tendons were divided into two equal groups and treated with platelet-rich plasma (PRP) or left untreated. Tendon tissue was harvested at 1, 2, 3, 4, and 6 weeks after treatment, and sections were stained with hematoxylin-eosin and monoclonal antibodies against CD31 and type I collagen. ResultsCollagen fibers proliferated more densely early after severance, and subsequent remodeling of the collagen fibers and approximation of normal tendinous tissue occurred earlier in the PRP group than in the control group. The fibroblast number was significantly higher in the PRP group than in the control group at 1 and 2 weeks. Similarly, the area ratio of CD31-positive cells was significantly higher in the PRP group than in the control group at 1 and 2 weeks. Positive staining for type I collagen was more intense in the PRP group than in the control group after 3 weeks, indicating tendon maturation. ConclusionAdministration of PRP shortened the inflammatory phase and promoted tendon healing during the proliferative phase.

A novel diffusion-tensor MRI approach for skeletal muscle fascicle length measurements.

Musculoskeletal (dys‐)function relies for a large part on muscle architecture which can be obtained using Diffusion‐Tensor MRI (DT‐MRI) and fiber tractography. However, reconstructed tracts often continue along the tendon or aponeurosis when using conventional methods, thus overestimating fascicle lengths. In this study, we propose a new method for semiautomatic segmentation of tendinous tissue using tract density (TD). We investigated the feasibility and repeatability of this method to quantify the mean fascicle length per muscle. Additionally, we examined whether the method facilitates measuring changes in fascicle length of lower leg muscles with different foot positions. Five healthy subjects underwent two DT‐MRI scans of the right lower leg, with the foot in 15° dorsiflexion, neutral, and 30° plantarflexion positions. Repeatability of fascicle length measurements was assessed using Bland–Altman analysis. Changes in fascicle lengths between the foot positions were tested using a repeated multivariate analysis of variance (MANOVA). Bland–Altman analysis showed good agreement between repeated measurements. The coefficients of variation in neutral position were 8.3, 16.7, 11.2, and 10.4% for soleus (SOL), fibularis longus (FL), extensor digitorum longus (EDL), and tibialis anterior (TA), respectively. The plantarflexors (SOL and FL) showed significant increase in fascicle length from plantarflexion to dorsiflexion, whereas the dorsiflexors (EDL and TA) exhibited a significant decrease. The use of a tract density for semiautomatic segmentation of tendinous structures provides more accurate estimates of the mean fascicle length than traditional fiber tractography methods. The method shows moderate to good repeatability and allows for quantification of changes in fascicle lengths due to passive stretch.

Kinesio taping in patients with lateral epicondylitis

Lateral epicondylitis (LE) is a painful condition that affects the tendinous tissue of the lateral epicondyle of the humerus and leads to loss of function of the affected limb. Therefore it can have a major impact on the patient's social and personal life. Many treatments are recommended for lateral epicondylitis; unfortunately the evidence is limited. The aim of study was to investigate the effect of kinesio taping (KT) on pain, grip strength and function in patients LE. Thirty-one (23 females, 8 males) patients with LE were included. KT was applied twice a week for 2 weeks. Pain at rest, activity of daily living (ADL), night and palpation on lateral epicondyle was evaluated with the visual analog scale (VAS 0-10 cm), and the grip strength was measured with a hand held dynamometer. The stage of the disease was evaluated by the Nirschl score and the functional status was assessed with Patient-Rated Forearm Evaluation Questionnaire (PRTEQ) score. These parameters were evaluated before, at 2 weeks and 6 weeks after treatment. Patients' satisfaction was also recorded on a Likert scale after treatment at 2 weeks and 6 weeks. The average age of the patients was 43.58 ± 9.02. The dominant limb was affected in 64.5% (20) of the patients. After the application of KT on lateral epicondyle, there was a significant improvement in all parameters in terms of pain, Nirschl score, hand grip strength, patient satisfaction, and PRTEQ scores at 2 and 6 weeks. Kinesio taping can be an effective treatment method in LE. This application improves pain, grip strength and functional status of the patients with LE.

A mathematical model characterising Achilles tendon dynamics in flexion

The purpose of this study is to acquire mechanistic knowledge of the gastrocnemius muscle-Achilles tendon complex behaviour during specific movements in humans through mathematical modelling. Analysis of this muscle-tendon complex was performed to see if already existing muscle-tendon models of other parts of the body could be applied to the leg muscles, especially the gastrocnemius muscle-Achilles tendon complex, and whether they could adequately characterise its behaviour. Five healthy volunteers were asked to take part in experiments where dorsiflexion and plantar flexion of the foot were studied. A model of the Achilles tendon-gastrocnemius muscle was developed, incorporating assumptions regarding the mechanical properties of the muscle fibres and the tendinous tissue in series. Ultrasound images of the volunteers, direct measurements and additional mathematical calculations were used to parameterise the model. Ground reaction forces, forces on specific joints and moments and angles for the ankle were obtained from a Vicon 3D motion capture system. Model validation was performed from the experimental data captured for each volunteer and from reconstruction of the movements of specific trajectories of the joints, muscles and tendons involved in those movements.