Tendon Strain Research Articles

Analytical prediction of nonlinear behaviors of beams post-tensioned by unbonded tendons considering shear deformation and tension stiffening effect

ABSTRACT This is a proposal for a nonlinear analytical model that was developed to predict the structural response of post-tensioned beam with unbonded tendon. The structural response includes deflections under the service load before or after cracking, as well as the ultimate load capacity. A comprehensive procedure for the deflection calculation was implemented, considering the additional shear deformation and tension stiffening effect. The shear deformation calculation is based on the Timoshenko beam theory, considering the shear modulus reduction upon cracking. Furthermore, a modification of the tension stiffening model from CEB–FIP Model Code 1990 is proposed to account for the significant strain concentration in the post-yielding region. A fixed-point iterative procedure is introduced in the prediction model to compute the incremental strain in the unbonded tendon. Each iteration brings the estimated strain increase in the tendon closer to the actual value until it is reasonably accurate. Predictive accuracy of the proposed model in both load–deflection relationships and strain rates, as a function of deflections, is successfully validated against experimental beam tests and a nonlinear finite element analysis considering concrete plasticity, respectively.

The Role of Sonoelastography in the Diagnosis of Supraspinatus Tendinosis

Purpose: The aim of the study was to evaluate the sensitivity and specificity of compressive elastosonography (“Strain Elastography”), integrated with the B-mode ultrasound examination, in supraspinatus tendinosis, using magnetic resonance imaging as the gold standard for diagnosis. We also verified the intra-observer reproducibility of this elastosonographic method. Materials and Methods: The supraspinatus tendons of 30 patients with shoulder pain and positive magnetic resonance imaging for tendinosis were examined with B-Mode ultrasound and compressive elastosonography in the absence of full-thickness tendon ruptures. At the same time, 30 control individuals, asymptomatic for shoulder pain and with a negative history of previous diseases affecting the rotator cuff, were examined with B-Mode ultrasound and compressive elastosonography. The MRI exam was used as a gold standard reference exam for the diagnosis of tendinosis. At the “Strain” elastosonography the images were evaluated qualitatively with the color elastogram and quantitatively with the percentages of deformation of the supraspinatus tendon (Strain T), of the deltoid muscle used as reference tissue (Strain R) and of the SR/ST ratio (Ratio). Results and Conclusions: The comparison between the group of individuals with tendinosis and the control group shows a statistically significant difference (p<0.05) for the Ratio values (SR/ST), respectively: 4.7 ± 0.14 vs 5.3 ± 0.19. The different Ratio values indicate that the supraspinatus tendon, when compared with the deltoid muscle, is softer in patients with tendinosis than in the control group. As indicated by the statistical analysis of the ROC curve, the Ratio value of 4.8 represents the best sensitivity and specificity data (70% and 61% respectively). Elastosonography can therefore provide added value, compared to the conventional ultrasound examination only, to confirm the diagnosis of supraspinatus tendinosis. The analysis showed a low variance of results, due to its excellent intra-observer reproducibility (intraclass correlation coefficient = 0.86). Future studies could aim to describe any changes in Stain T, Strain R and Ratio values in a cohort of individuals stratified by gender, age and BMI.

Intratendinous Strain Variations of the Supraspinatus Tendon Depending on Repair Technique: A Biomechanical Analysis Regarding the Cause of Medial Cuff Failure

Background: Double-row (DR) and transosseous-equivalent (TOE) techniques for rotator cuff repair offer more stability and promote better tendon healing compared with single-row (SR) repairs and are preferred by many surgeons. However, they can lead to more disastrous retear patterns with failure at the medial anchor row or the musculotendinous junction. The biomechanics of medial cuff failure have not been thoroughly investigated thus far. Purpose: To investigate the intratendinous strain distribution within the supraspinatus tendon depending on repair technique. Study Design: Controlled laboratory study. Methods: Twelve fresh-frozen cadaveric shoulders were used. The intratendinous strain within the supraspinatus tendon was analyzed in 2 regions—(1) at the footprint at the greater tuberosity and (2) medial to the footprint up to the musculotendinous junction—using a high-resolution 3-dimensional camera system. Testing was performed at submaximal loads of 40 N, 60 N, and 80 N for intact tendons, after SR repair, after DR repair, and after TOE repair. Results: The tendon strain of the SR group differed significantly in both regions from that of the intact tendons and the TOE group at 40 N (P≤ .043) and from the intact tendons, the DR group, and the TOE group at 60 N and 80 N (P≤ .048). SR repairs showed more tendon elongation at the footprint and less elongation medial to the footprint. DR and TOE repairs did not provide significant differences in tendon strain when compared with the intact tendons. However, the increase in tendon strain medial to the footprint from 40 N to 80 N was significantly more pronounced in the DR and TOE group (P≤ .029). Conclusion: While DR and TOE repair techniques more closely reproduced the strains of the supraspinatus tendon than did SR repair in a cadaveric model, they showed a significantly increased tendon strain at the musculotendinous junction with higher loads in comparison with the intact tendon. Clinical Relevance: DR and TOE rotator cuff reconstructions lead to a more anatomic tendon repair. However, their use has to be carefully evaluated whenever tendon quality is diminished, as they lead to a more drastic increase in tendon strain medial to the footprint, putting these repairs at risk of medial cuff failure.

Assessment of Frequent Work Related Musculoskeletal Disorders in Patients Visiting the Physiothrapy OPD of Civil Hospital Quetta, Pakistan: A Cross Sectional Survey

Background: Work related musculoskeletal disorders (WRMSD) are the sort of disorders which involvessoft tissues. The involvement of soft tissues can be due to the over use, restlessness and improper use. Themain target of WRMSD are working indicuduals.it may cause muscle strain, ligament strain, tendon strain,tendentious and bursitis.Methods: The cross section survey was conducted and data was collected from July to October 2018 fromcivil hospital Quetta, Pakistan. A self-constructed proforma was used among the 97 patients who meet theinclusion and exclusion criteria and Spss version 23 was used.Results: The majority (n=49, 50.5%) were belongs to age group of 21 to 35 and were (n=51, 52.6%) weremale. In marital status majority (n=64, 66%) were married. In involvement of part majority (n=28, 28.9%)were suffering from lower back problem. After checking the type of injury (n=48, 49.5%) were sufferingfrom muscular strain. In the context of onset of injury majority (N=41, 42.3%) were experienced theirproblem suddenly.Conclusion: The study finalized that WRMSD is most common in working individuals especially in olderand females. The WRMDS puts heavy burden on the society, annually. As the participants who belongs tolow socio economic status are more vulnerable for WRMDS.

Quantifying mechanical loading and elastic strain energy of the human Achilles tendon during walking and running

The purpose of the current study was to assess in vivo Achilles tendon (AT) mechanical loading and strain energy during locomotion. We measured AT length considering its curve-path shape. Eleven participants walked at 1.4 m/s and ran at 2.5 m/s and 3.5 m/s on a treadmill. The AT length was defined as the distance between its origin at the gastrocnemius medialis myotendinous junction (MTJ) and the calcaneal insertion. The MTJ was tracked using ultrasonography and projected to the reconstructed skin surface to account for its misalignment. Skin-to-bone displacements were assessed during a passive rotation (5°/s) of the ankle joint. Force and strain energy of the AT during locomotion were calculated by fitting a quadratic function to the experimentally measured tendon force–length curve obtained from maximum voluntary isometric contractions. The maximum AT strain and force were affected by speed (p < 0.05, ranging from 4.0 to 4.9% strain and 1.989 to 2.556 kN), yet insufficient in magnitude to be considered as an effective stimulus for tendon adaptation. Besides the important tendon energy recoil during the propulsion phase (7.8 to 11.3 J), we found a recoil of elastic strain energy at the beginning of the stance phase of running (70–77 ms after touch down) between 1.7 ± 0.6 and 1.9 ± 1.1 J, which might be functionally relevant for running efficiency.

A Functional High-Load Exercise Intervention for the Patellar Tendon Reduces Tendon Pain Prevalence During a Competitive Season in Adolescent Handball Players.

Imbalances of muscle strength and tendon stiffness may increase the risk for patellar tendinopathy in growing athletes. The present study investigated if a functional high-load exercise intervention, designed to facilitate tendon adaptation and reduce muscle-tendon imbalances, may prevent patellar tendon pain in adolescent male handball players (12–14 years). Tendon pain prevalence (using VISA-P scores), knee extensor strength, vastus lateralis (VL) architecture and patellar tendon mechanical properties were measured at four measurement time points (M1–M4) over a season. The control group (CON; n = 18; age 13.1 ± 0.7 yrs, height 170 ± 8 cm, mass 58 ± 10 kg) followed the usual strength training plan, including muscular endurance and explosive strength components. In the experimental group (EXP; n = 16; 13.1 ± 0.6 yrs, 169 ± 11 cm, 58 ± 16 kg), two sessions per week with functional high-load exercises for the patellar tendon were integrated in the strength training schedule, aiming to provide repetitive high-intensity loading of at least 3 s loading duration per repetition. While in the control group 30% of the athletes reported a clinically significant aggravation of symptoms, all players in the experimental group remained or became pain-free at M2 until the end of the season. There was a similar increase of strength (normalized to body mass; CON: 3.1%, d = 0.22; EXP: 6.8%, d = 0.47; p = 0.04) and VL thickness (CON: 4.8%, d = 0.28; EXP: 5.7%, d = 0.32; p < 0.001) in both groups, but no significant changes of tendon stiffness or maximum tendon strain. Further, both groups demonstrated similar fluctuations of tendon strain over time. We conclude that functional high-load exercises can reduce the prevalence of patellar tendon pain in adolescent athletes even without a reduction of tendon strain.

Evidence that ageing does not influence the uniformity of the muscle–tendon unit adaptation in master sprinters

Differences in the adaptation processes between muscle and tendon in response to mechanical loading can lead to non-uniform mechanical properties within the muscle–tendon unit (MTU), potentially increasing injury risk. The current study analysed the mechanical properties of the triceps surae (TS) MTU in 10 young (YS; 22 ± 3 yrs) and 10 older (OS; age 65 ± 8 yrs; i.e. master) (inter)national level sprinters and 11 young recreationally active adults (YC; 23 ± 3 yrs) to detect possible non-uniformities in muscle and tendon adaptation due to habitual mechanical loading and ageing. Triceps surae muscle strength, tendon stiffness and maximal tendon strain were assessed in both legs during maximal voluntary isometric plantarflexion contractions via dynamometry and ultrasonography. Irrespective of the leg, OS and YC in comparison to YS demonstrated significantly (P < 0.05) lower TS muscle strength and tendon stiffness, with no differences between OS and YC. Furthermore, no group differences were detected in the maximal tendon strain (average of both legs: OS 3.7 ± 0.8%, YC 4.4 ± 0.8% and YS 4.3 ± 0.9%) as well as in the inter-limb symmetry indexes in muscle strength, tendon stiffness and maximal tendon strain (range across groups: –5.8 to 4.9%; negative value reflects higher value for the non-preferred leg). Thus, the findings provide no clear evidence for a disruption in the TS MTU uniformity in master sprinters, demonstrating that ageing tendons can maintain their integrity to meet the increased functional demand due to elite sports.

Patellar Tendon Orientation and Strain Are Predictors of ACL Strain In Vivo During a Single-Leg Jump.

Background:There is little in vivo data that describe the relationships between patellar tendon orientation, patellar tendon strain, and anterior cruciate ligament (ACL) strain during dynamic activities. Quantifying how the quadriceps load the ACL via the patellar tendon is important for understanding ACL injury mechanisms.Hypothesis:We hypothesized that flexion angle, patellar tendon orientation, and patellar tendon strain influence ACL strain during a single-leg jump. Specifically, we hypothesized that patellar tendon and ACL strains would increase concurrently when the knee is positioned near extension during the jump.Study Design:Descriptive laboratory study.Methods:Models of the femur, tibia, ACL, patellar tendon, and quadriceps tendon attachment sites of 8 male participants were generated from magnetic resonance imaging (MRI). High-speed biplanar radiographs during a single-leg jump were obtained. The bone models were registered to the radiographs, thereby reproducing the in vivo positions of the bones, ligament, and tendon attachment sites. Flexion angle, patellar tendon orientation, patellar tendon strain, and ACL strain were measured from the registered models. ACL and patellar tendon strains were approximated by normalizing their length at each knee position to their length at the time of MRI. Two separate bivariate linear regression models were used to assess relationships between flexion angle and patellar tendon orientation and between ACL strain and patellar tendon strain. A multivariate linear regression model was used to assess whether flexion angle and patellar tendon strain were significant predictors of ACL strain during the inflight and landing portions of the jump.Results:Both flexion angle and patellar tendon strain were significant predictors (P < .05) of ACL strain. These results indicate that elevated ACL and patellar tendon strains were observed concurrently when the knee was positioned near extension.Conclusion:Concurrent increases in patellar tendon and ACL strains indicate that the quadriceps load the ACL via the patellar tendon when the knee is positioned near extension.Clinical Relevance:Increased ACL strain when the knee is positioned near extension before landing may be due to quadriceps contraction. Thus, landing with unanticipated timing on an extended knee may increase vulnerability to ACL injury as a taut ligament is more likely to fail.

Q&amp;A: Rating an Adductor Longus Tendon Tear

Q&amp;A: Rating an Adductor Longus Tendon Tear

Effects of cyclic loading on the mechanical properties and failure of human patellar tendon

Patellar tendinopathy is a common overuse injury in sports such as volleyball, basketball, and long-distance running. Microdamage accumulation, in response to repetitive loading of the tendon, plays an important role in the pathophysiology of patellar tendinopathy. This damage presents mechanically as a reduction in Young’s modulus and an increase in residual strain. In this study, 19 human patellar tendon samples underwent cyclic testing in load control until failure, segmented by four ramped tests where digital image correlation (DIC) was used to assess anterior surface strain distributions. Ramped tests were performed prior to cyclic testing and at timepoints corresponding to 10%, 20%, and 30% of cyclic stiffness reduction. Young’s modulus significantly decreased and cyclic energy dissipation significantly increased over the course of cyclic testing. The DIC analysis illustrated a heterogeneous strain distribution, with strain concentrations increasing in magnitude and size over the course of cyclic testing. Peak stress and initial peak strain magnitudes significantly correlated with the number of cycles to failure (r2 = 0.65 and r2 = 0.57, respectively, p < 0.001); however, the rates of peak cyclic strain and modulus loss displayed the highest correlations with the number of cycles to failure (r2 = 96% and r2 = 86%, respectively, p < 0.001). The high correlation between the rates of peak cyclic strain and modulus loss suggest that non-invasive methods to continuously monitor tendon strain may provide meaningful predictions of overuse injury in the patellar tendon.

Injuries in Estonian professional ballet dancers in the 2019/2020 season

The aim of the study was to find the occurrence of musculoskeletal injuries in Estonia professional ballet dancers in the 2019/2020 season. A total of 62 dancers participated in the study, 25 were male and 37 female dancers. This study was a questionnaire-based, which was compiled on similar studies to collect the data among ballet dancers working in Estonia. The study showed that 58% of dancers were injured in the last 12 months. The most common type of dance injury during this period was muscle or tendon strain (33%), followed chronic inflammation (21%) and ankle sprain (20%). The most common injured body site was foot (20%), ankle (18%) and knee joint (10%). The highest number of injuries occurred during rehearsals (44%), classical class (27%), and during performances (16%). More than half of Estonian ballet dancers sustained at least one injury during the last twelve months. The most common types of injury were muscle or tendon strain, chronic inflammation and ankle sprain. The highest number of injuries occurred in the foot, whereas the highest number of injuries occurred during rehearsals.

Monitoring Muscle-Tendon Adaptation Over Several Years of Athletic Training and Competition in Elite Track and Field Jumpers.

Differences in muscle and tendon responsiveness to mechanical stimuli and time courses of adaptive changes may disrupt the interaction of the musculotendinous unit (MTU), increasing the risk for overuse injuries. We monitored training-induced alterations in muscle and tendon biomechanical properties in elite jumpers over 4 years of athletic training to detect potential non-synchronized adaptations within the triceps surae MTU. A combined cross-sectional and longitudinal investigation over 4 years was conducted by analyzing triceps surae MTU mechanical properties in both legs via dynamometry and ultrasonography in 67 elite track and field jumpers and 24 age-matched controls. Fluctuations in muscle and tendon adaptive changes over time were quantified by calculating individual residuals. The cosine similarity of the relative changes of muscle strength and tendon stiffness between sessions served as a measure of uniformity of adaptive changes. Our cross-sectional study was unable to detect clear non-concurrent differences in muscle strength and tendon stiffness in elite jumpers. However, when considering the longitudinal data over several years of training most of the jumpers demonstrated greater fluctuations in muscle strength and tendon stiffness and hence tendon strain compared to controls, irrespective of training period (preparation vs. competition). Moreover, two monitored athletes with chronic Achilles tendinopathy showed in their affected limb lower uniformity in MTU adaptation as well as higher fluctuations in tendon strain over time. Habitual mechanical loading can affect the MTU uniformity in elite jumpers, leading to increased mechanical demand on the tendon over an athletic season and potentially increased risk for overuse injuries.

Contribution of Achilles tendon mechanical properties to torque steadiness in persons with transfemoral amputation.

How Achilles tendon mechanics and plantar flexion strength and torque steadiness are altered in the intact leg of persons with trauma-related amputation is unknown. Understanding Achilles tendon mechanics following amputation will further inform rehabilitation approaches to enhance posture, balance, and force control. Conduct a pilot study to quantify plantar flexion maximal voluntary contraction torque, torque steadiness, and Achilles tendon mechanics in persons with unilateral trauma-related transfemoral amputation and controls without amputation. Cross-sectional study. Isometric plantar flexion maximal voluntary contractions were performed with the intact leg of ten males with transfemoral amputation (48 ± 14 years) and the dominant leg of age-matched male controls without amputation. Torque steadiness was calculated as the coefficient of variation in torque over 6 s during submaximal tracking tasks (5%, 10%, 25%, 50%, and 75% maximal voluntary contraction). Achilles tendon elongation and cross-sectional area were recorded with ultrasound to calculate strain, stress, and stiffness. Maximal voluntary contraction and torque steadiness did not differ between persons with amputation (90.6 ± 31.6 N m, 3.7 ± 2.0%) and controls (95.8 ± 26.8 N m, 2.9 ± 1.2%; p > 0.05). Tendon stiffness (21.1 ± 18.2 N/mm) and strain (5.2 ± 1.3%) did not differ between groups (p > 0.05). Tendon cross-sectional area was 10% greater in persons with amputation leading to 29% lower stress (p = 0.021). Maximal voluntary contraction was a predictor of a lower coefficient of variation in torque (R2 = 0.11, p < 0.05). Persons with trauma-related transfemoral amputation do not differ in plantar flexion maximal voluntary contraction and torque steadiness of the intact leg compared with controls without amputation. Larger tendon cross-sectional area reduces stress and enables distribution of force across a greater area.

DFEM of a post-tensioned precast concrete segmental bridge with unbonded external tendons subjected to prestress changes

Being cost-effective, rapid construction, high transportability, and maintainability, post-tensioned precast concrete segmental bridges (PT-PCSBs) have been one of the most preferred choices for sites that are restrictive to access. Yet, deterioration due to aging, improper maintenance, and unaccounted shrinkage of bridge decks can cause unexpected prestress loss/gain and alter the structural behaviour of PT-PCSBs, especially with unbonded external tendons. In this regard, this paper presents the development of a rigorous and detailed three-dimensional discrete finite element model (DFEM) for a PT-PCSB, of which both global load-deflection behaviour and local responses were verified against experimental results by Takebayashi et al. (1994) and Jiang et al. (2018). The verified model was then adopted to investigate the effects of prestress loss/gain on the structural responses and failure behaviour. Based on the analysis results, a 20% increase/decrease of prestressing can lead to a 10% increase/16.8% decrease of the moment resistance but a 30.2% decrease/36.6% increase of the deflection capacity. At large prestressing level, e.g. 0.874 fpu, significant crushing of concrete can occur in the bottom region of the bridge at ULS that significantly restricts the joint opening, tendon strain development, and ductility. On the contrary, at the extremely low prestressing level of 0.125 fpu, the bridge decompresses under its self-weight and is very unstable under additional load, resulting in very low ductility and moment resistance. Furthermore, for a regular prestress level of around 0.6 fpu, the stress change in tendons from the effective prestress to the stress in ULS matches the recommendations by ACI318 and AASHTO LRFD but is underestimated by EC2. Yet, the ultimate tendon stress which is less sensitive to the prestress change may be more suitable than the stress change in evaluating the ULS behaviour of PT-PCSBs with unbonded tendons.

POSTERIOR TIBIAL TENDON INJURY - IS MISSED DIAGNOSIS, A POSSIBILITY? SHOULD IT BE SUSPECTED IN ALLANKLE EVERSION SPRAINS? - A CASE REPORT

Ankle sprains are one of the most common injuries that occur among people of all ages and accounts for 75% of ankle injuries and for 10 to 30 percent of sports-related injuries in young athletes. Inversion sprain is more common than eversion ankle sprain, to result in injury to the lateral ligament complex. Though injury to the posterior tibial tendon is not a very common injury associated with eversion ankle sprain, it often can be overlooked and missed in the initial physical examination. We present a case of a college student who sustained a twisting injury to his left ankle while playing football. After initial history, physical examination and plain radiographic evaluation, a diagnosis of eversion ankle sprain was made by a general practitioner and treated conservatively. Due to persistent symptoms and local signs, subsequent evaluation with an MRI study revealed tibialis posterior (TP) tendon strain with diffuse soft tissue swelling extending up to lower third of the leg and associated Grade I osteochondral injury to the posterolateral aspect of talus. The injury was successfully treated with medial arch support ankle brace, analgesics, guarded weight bearing and physiotherapy with full functional recovery in 12 weeks.

Strain measurement of the deep layer of the supraspinatus tendon using fresh frozen cadaver: The influence of shoulder elevation

The shoulder is a uniquely complex large joint. Effective and safe physical therapy efforts towards rehabilitating injured and repaired shoulders requires a thorough understanding of shoulder mechanics from both generalized and very specific perspectives. Numerous biomechanical studies have been published on the shoulder. None of the studies, to our knowledge, considered the strain of the deep layers of the supraspinatus tendon for scapular plane elevation. Ten unilateral fresh-frozen human cadaveric specimens were used for the study. Scapular plane angles ranging from -10 to 30 degrees were evaluated for tensile loads, ranging from 0 to 120Newtons, exerted on the supraspinatus tendon. Strain measurements that specifically targeted the deep layer of the supraspinatus tendon during tensile loading were recorded. Strains recorded in the supraspinatus deep layer while increasing tendon force of the supraspinatus were significant for isometric gleno-humeral elevation of 30° and 20°. The response of strain to tendon force was less pronounced for 10° or less of gleno-humeral elevation. When performing isometric shoulder exercise regimens, rotator cuff forces and both surface and deep tendon strain, relative to scapular positioning, are relevant and should be considered.

The influence of Achilles tendon mechanical behaviour on \u201capparent\u201d efficiency during running at different speeds

PurposeWe investigated the role of elastic strain energy on the “apparent” efficiency of locomotion (AE), a parameter that is known to increase as a function of running speed (up to 0.5–0.7) well above the values of “pure” muscle efficiency (about 0.25–0.30).MethodsIn vivo ultrasound measurements of the gastrocnemius medialis (GM) muscle–tendon unit (MTU) were combined with kinematic, kinetic and metabolic measurements to investigate the possible influence of the Achilles tendon mechanical behaviour on the mechanics (total mechanical work, WTOT) and energetics (net energy cost, Cnet) of running at different speeds (10, 13 and 16 km h−1); AE was calculated as WTOT/Cnet.ResultsGM fascicles shortened during the entire stance phase, the more so the higher the speed, but the majority of the MTU displacement was accommodated by the Achilles tendon. Tendon strain and recoil increased as a function of running speed (P < 0.01 and P < 0.001, respectively). The contribution of elastic energy to the positive work generated by the MTU also increased with speed (from 0.09 to 0.16 J kg−1 m−1). Significant negative correlations (P < 0.01) were observed between tendon work and metabolic energy at each running speed (the higher the tendon work the lower the metabolic demand) and significant positive correlations were observed between tendon work and AE (P < 0.001) at each running speed (the higher the tendon work the higher the efficiency).ConclusionThese results support the notion that the dynamic function of tendons is integral in reducing energy expenditure and increasing the “apparent” efficiency of running.

Speckle Track Analysis of Ultrasound Images Produce Reliable Measures of Supraspinatus Tendon Strain During a Maximal Isometric Contraction

Introduction: Ultrasound speckle tracking is an emergent method in studying musculoskeletal physiology and disease. The precision and reliability of supraspinatus tendon strain measurements have not been explored. The purpose of this study was to examine the reliability of speckle tracking to measure supraspinatus tendon strain. Methods: Forty-two (42) participants participated in this study. Five (5) ultrasound images of the participant’s right shoulder supraspinatus tendon were collected during a maximal voluntary isometric abduction contraction. Cine loop video files of the 5 imaging trials were imported into Ncorr software for speckle track analysis. Axial and longitudinal strain measurements were made for the bursal side, midsubstance, and joint side of the thickest portion of the supraspinatus tendon. Reliability of the strain measures was determined using interclass correlation coefficients (ICC). Bland-Altman plots were created in order to explore systematic error. Results: Mean strain of the supraspinatus tendon ranged from 1.791 to -2.120 %. ICC values for the longitudinal and axial strains of both within and between images were high (&gt;0.9) for all locations of the tendon, demonstrating very good reliability. The 95% for the MDC was large for all measurements of strain, except the axial strain at the mid-substance demonstrating poor precision. Conclusion: The results of the investigation show evidence of very good reliability, poor precision, and some evidence of systematic error. The very good ICC values support the hypothesis that speckle tracking does produce reliable strain measurements. The large MDC values do not support the hypothesis that speckle tracking produces precise strain measurements. Improvements in ultrasound image quality and the shoulder stabilization process need to be made before ultrasound speckle tracking will be a viable research method for the supraspinatus tendon.

Targeted Achilles Tendon Training and Rehabilitation Using Personalized and Real-Time Multiscale Models of the Neuromusculoskeletal System.

Musculoskeletal tissues, including tendons, are sensitive to their mechanical environment, with both excessive and insufficient loading resulting in reduced tissue strength. Tendons appear to be particularly sensitive to mechanical strain magnitude, and there appears to be an optimal range of tendon strain that results in the greatest positive tendon adaptation. At present, there are no tools that allow localized tendon strain to be measured or estimated in training or a clinical environment. In this paper, we first review the current literature regarding Achilles tendon adaptation, providing an overview of the individual technologies that so far have been used in isolation to understand in vivo Achilles tendon mechanics, including 3D tendon imaging, motion capture, personalized neuromusculoskeletal rigid body models, and finite element models. We then describe how these technologies can be integrated in a novel framework to provide real-time feedback of localized Achilles tendon strain during dynamic motor tasks. In a proof of concept application, Achilles tendon localized strains were calculated in real-time for a single subject during walking, single leg hopping, and eccentric heel drop. Data was processed at 250 Hz and streamed on a smartphone for visualization. Achilles tendon peak localized strains ranged from ∼3 to ∼11% for walking, ∼5 to ∼15% during single leg hop, and ∼2 to ∼9% during single eccentric leg heel drop, overall showing large strain variation within the tendon. Our integrated framework connects, across size scales, knowledge from isolated tendons and whole-body biomechanics, and offers a new approach to Achilles tendon rehabilitation and training. A key feature is personalization of model components, such as tendon geometry, material properties, muscle geometry, muscle-tendon paths, moment arms, muscle activation, and movement patterns, all of which have the potential to affect tendon strain estimates. Model personalization is important because tendon strain can differ substantially between individuals performing the same exercise due to inter-individual differences in these model components.

Non-remitting Gluteal Pain In An Adolescent Soccer Player

HPI: 14 y/o male soccer player presents to clinic with 12 months of right gluteal pain when active or sitting for a prolonged time. He described the pain as dull with normal activity and sharp with low levels of exertion particularly in hip flexion. His pain is maximal during soccer while kicking the ball with his opposite foot. In addition, he reports point tenderness over the proximal right hamstring and while sitting down on hard surfaces. He was evaluated roughly 1 year ago by an outside physician with a normal XR of the pelvis. Per patient and father reported an “injury to the Sits bone”. Patient was subsequently taken out of sports for 6 months and had a non-US guided corticosteroid injection into the posterior thigh 3 months prior to clinic visit. The injection provided short term relief, no additional treatment (PT) was prescribed. ROS: CONSTITUTIONAL: No fevers, chills, sweats, night pain or weight changes. CARDIOVASCULAR: No chest pains, palpitations, orthopnea and paroxysmal nocturnal dyspnea. RESPIRATORY: No dyspnea on exertion, no wheezing or cough. MUSCULOSKELETAL: per HPI NEUROLOGIC: No numbness, tingling or weakness. PHYSICAL EXAM: Gait: Able to bear weight with a normal gait MSK: No swelling, ecchymosis ROM: Full ROM intact both actively and passively. There was mild pain with active deep flexion during squat Straight leg raise: Significant for pain on proximal right hamstring Tenderness: Over ischial tuberosity and toward proximal hamstring Strength: 4/5 on hip extension remainder of strength testing unremarkable Log Roll: neg FABER/FADIR neg/neg Ober Test: neg Thomas Test: neg Sensation: intact to light touch DIFFERENTIAL DIAGNOSIS: Chronic hamstring strain Bone contusion Tumor Osteomyelitis INITIAL TESTING IN CLINIC: X-Ray Hip AP/lateral: Irregular lucency along inferolateral aspect of right ischium. Correlates to insertion of the hamstring. However, the appearance is not typical for an avulsion injury or tendon strain. Femoro-acetabular joints preserved. MRI: Ill-defined area within the ischium approximately 1.7 x 0.6 x 3.6 cm corresponding to the suspicious area seen on prior x-ray. Findings are likely due to a healing avulsion fracture of the right ischial tuberosity. FINAL WORKING DIAGNOSIS: Healing avulsion fracture over right ischial tuberosity, clinically improving with PT