Medial Head Of Gastrocnemius Muscle Research Articles

Floppy infant syndrome as a first manifestation of LMNA-related congenital muscular dystrophy

LMNA-related congenital muscular dystrophy (L-CMD) is the most severe phenotypic form of skeletal muscle laminopathies. This paper reports clinical presentation of the disease in 15 Polish patients from 13 families with genetically confirmed skeletal muscle laminopathy. In all these patients floppy infant syndrome was the first manifestation of the disease. The genetic diagnosis was established by next generation sequencing (targeted panel or exome; 11 patients) or classic Sanger sequencing (4 patients). In addition to known pathogenic LMNA variants: c.116A > G (p.Asn39Ser), c.745C > T (p.Arg249Trp), c.746G>A (p.Arg249Gln), c.1072G>A (p.Glu358Lys), c.1147G>A (p.Glu383Lys), c.1163G>C (p.Arg388Pro), c.1357C > T (p.Arg453Trp), c.1583C > G (p.Thr528Arg), we have identified three novel ones: c.121C > G (p.Arg41Gly), c.1127A > G (p.Tyr376Cys) and c.1160T > C (p.Leu387Pro). Eleven patients had de novo mutations, 4 - familial. In one family we observed intrafamilial variability of clinical course: severe L-CMD in the male proband, intermediate form in his sister and asymptomatic in their mother. One asymptomatic father had somatic mosaicism. L-CMD should be suspected in children with hypotonia in infancy and delayed motor development, who have poor head control, severe hyperlordosis and unstable and awkward gait. Serum creatine kinase may be high (~1000IU/l). Progression of muscle weakness is fast, leading to early immobilization. In some patients with L-CMD joint contractures can develop with time. MRI shows that the most frequently affected muscles are the serratus anterior, lumbar paraspinal, gluteus, vastus, adductor magnus, hamstrings, medial head of gastrocnemius and soleus. Ultra-rare laminopathies can be a relatively common cause of generalized hypotonia in children. Introduction of wide genome sequencing methods was a breakthrough in diagnostics of diseases with great clinical and genetic variability and allowed approach "from genotype do phenotype". However target sequencing of LMNA gene could be considered in selected patients with clinical picture suggestive for laminopathy.

Use of Tensiomyography in Evaluating Sex-Based Differences in Resistance-Trained Individuals After Plyometric and Isometric Midthigh Pull Postactivation Potentiation Protocols.

Herring, CH, Goldstein, ER, and Fukuda, DH. Use of tensiomyography in evaluating sex-based differences in resistance-trained individuals after plyometric and isometric midthigh pull postactivation potentiation protocols. J Strength Cond Res 35(6): 1527-1534, 2021-The purposes of this study were to determine if there are sex-based differences in muscular contractile properties as measured by tensiomyography (TMG) and to determine if plyometrics or the isometric midthigh pull are effective methods of eliciting postactivation potentiation (PAP). Thirty strong, resistance-trained men (n = 15) and women (n = 15) underwent 3 testing days consisting of a PAP or control protocol, and pre-TMG and post-TMG and performance testing. Contractile properties from TMG were assessed in the gastrocnemius medial head (GMH), gluteus maximus (GM), rectus femoris (RF), and biceps femoris (BF). Performance testing included countermovement jumps (CMJs) and 30-m sprints. A time × sex interaction was found for GM delay time with women primarily influencing changes (mean difference = 2.74 ms) rather than men (mean difference = 1.32 ms). Main effects for time revealed an increase in GMH velocity of contraction (+0.004 mm·ms-1) and reductions in GM contraction time (-2.85 ms), GM delay time (-2.03 ms), RF delay time (-0.65 ms), CMJs (-2.74 cm), and 30-m time (0.05 seconds). Main effects for sex revealed greater values in women for GM contraction time (+15.50 ms), GM delay time (+6.65 ms), RF delay time (+2.26 ms), BF contraction time (+8.44 ms), BF delay time (+4.07 ms), BF maximal displacement (+2.27 mm), and 30-m time (+0.67 seconds), and lower values in women for GM velocity of contraction (-0.039 mm·ms-1) and CMJs (-13.46 cm).These findings may help practitioners optimize performance through enhanced assessments for injury risk, targeting specific muscles for training, and by selecting proper CAs and rest periods when using PAP.

Correlation analysis between lower limb muscle architectures and cycling power via ultrasonography

The primary purpose was to examine the relationship between the muscle architectural characteristics of short and long-distance cyclist—including muscle thickness, fascicle angle, and fascicle length—of the anterior thigh and posterior leg and its impact in 20-s cycling power. The secondary purpose was to clarify the muscle variables that predict the cycling power by using ultrasonography to measure the muscle architectural characteristics. Twenty-four varsity cyclists participated in this study, of whom 12 were short-distance cyclists and 12 were long-distance cyclists. B-mode ultrasonography was used to measure muscle architecture parameters. A cycle ergometer was used to measure the cycling power. The rectus femoris, vastus medialis, and medial head of gastrocnemius were significantly thicker in short-distance cyclists than in long-distance cyclists at every site (p < 0.05). Our analysis revealed that the rectus femoris fascicle length at the 30% level of the thigh was a significant independent predictor of the 20-s cycling power in short-distance cyclists, while the rectus femoris fascicle angle at the 50% level was that of the 20-s cycling power in long-distance cyclists. These findings highlight the significance of rectus femoris muscle architecture to cycling power.

Determinants of regeneration and strength of hamstrings after anterior cruciate ligament reconstruction-fate of hamstring tendon.

Arthroscopic reconstruction of anterior cruciate ligament (ACL) surgical procedure using hamstring autograft is themost common surgery performed in the arena of sports medicine and arthroscopy. Most studies in literature are ambiguous regarding the fate of hamstrings based on function, regenerative potential, and cross-sectional area (CSA). The aim of this research study is analysis of the fate of hamstring tendons (both semitendinosus and gracilis) during the time course for determinants of regeneration and strength. Fifty patients who were operated for unilateral isolated ACL reconstruction from July 2015 to June 2018 were evaluated for the fate of harvested hamstring tendons which included the following: regeneration, cross-sectional area (CSA), strength, and insertion of regenerated hamstrings by isometric torque and isokinetic strength. MRI of knee was performed for both knees concerning the semitendinosus (ST), gracilis (G), Sartorius, biceps femoris, and medial head of gastrocnemius. Eighty-four percent men and 16% women within a mean patient age of 34 ± 4.12 years were evaluated and all 50 (100%) patients demonstrated hamstring regeneration by the MRI measurements at six months and at one year post-ACL reconstruction. The torque of isometric knee flexion measured in 60° was found to be remarkably lower in the ACL-reconstructed lower extremity compared to that of the contralateral limb (87.13 ± 20.18% of BW), at 90° (49.17 ± 15.09% BW), and at 105° (43.91 ± 13.17% BW), respectively (p < 0.01). However, at 30° flexion and 45° flexion, the difference was insignificant (116.48 ± 21.07% BW for 30° and 100.16 ± 25.12% BW for 45°). It was found that the properties of musculotendinous units of ST and G were significantly transformed after their harvesting for ACL reconstruction and these weaknesses contribute to the flexion deficit of knee in the deeper range of flexion in the operated limb. Therefore, approaches facilitating tendon regeneration and preservation must be warranted.

A Study of Tibial Nerve in the Popliteal Fossa Along With Its Variations in Its Branching Pattern

Background: A detailed Knowledge of these variations in motor branching patterns will help the surgeons when certain procedures are done for calf reduction and also when selective neurectomy is required. It is also required by the anesthetists to give neurolytic blocks. Subjects and Methods: 40 formalin-fixed lower limbs of adult human cadavers were selected. The origin of the tibial nerve, variations in a branching pattern, number of muscular branches given was studied by dissection. The Level of origin of these nerves was taken to the apex of the head of the fibula (AHF). Results: In 70 % of specimens the origin of the Tibial Nerve was &lt; 12 cm and in 30 % it was between 12-24 cm above the level of AHF. In 10% of cases, the sural nerve originated from the nerve to the medial head of gastrocnemius (MHG). In 82.5% of specimens, the MHG received one branch from the tibial nerve and in 17.5% it received two branches. The lateral head of Gastrocnemius (LHG) received one branch from the tibial nerve. In 10%, there was a common branch for the LHG and the soleus muscle. 90% of specimens had one branch and 10% had two branches that supplied the soleus muscle. A single branch supplied the plantaris muscle. The popliteus muscle also received a single branch. Conclusion : The results in the study provide information that is required by the anatomists, surgeons, radiologists and anesthetists.

Impact of abdominal moxibustion in a period of day from 7 am to 9 am on improvement in post-stroke lower limb spasticity and muscle architecture parameter

To compare the therapeutic effect on post-stroke lower limb spasticity between the combined treatment of abdominal moxibustion from 7 am to 9 am and rehabilitation training and the simple rehabilitation training. A total of 100 patients with post-stroke lower limb spasticity were randomized into an observation group (50 cases, 3 cases dropped off) and a control group (50 cases, 4 cases dropped off ). In the control group, the basic treatment of internal medicine and rehabilitation training of the limbs were adopted. In the observation group, on the basis of the treatment in the control group, at the time zone from 7 am to 9 am, moxibustion on the abdomen with "eight-trigram" moxa box [the central moxa box accurately facing Shenque (CV 8)] was given, lasting for 2 h, once every two days. Both groups were treated for 6 weeks. Separately, before and after treatment, the score of Fugl-Meyer assessment of the lower extremity (FMA-LE) and the grade of modified Ashworth scale (MAS) of ankle joint were evaluated on the affected side in patients of the two groups. Muscle skeleton ultrasound (MSUS) was adopted to determine the first layer muscle thickness (MT) anterior to the tibia, the number of pennation angle (PA) and the length of muscle fibers in the medial head of gastrocnemius muscle on the affected side. Besides, after treatment, the therapeutic effect was evaluated in the two groups. After treatment, the score of FMA-LE and the grade of MAS of ankle joint on the affected side were both improved as compared with those before treatment in patients of the two groups (P<0.01, P<0.05). The improvements in the observation group were better than those in the control group (P<0.01, P<0.05). After treatment, MT anterior to the tibia, the number of PA and the length of muscle fibers in the medial head of gastrocnemius muscle on the affected side were all increased as compared with before treatment in patients of the two groups (P<0.01). The increase degree in the observation group was larger than that in the control group (P<0.01). The total effective rate was 93.6% (44/47) in the observation group, better than 80.4% (37/46) in the control group (P<0.05). The combined treatment of abdominal moxibustion from 7 am to 9 am and rehabilitation training effectively relieves post-stroke lower limb spasticity and improves the limb functions and muscle structure. The total effective rate of this combined treatment is better than that of simple rehabilitation training.

The effect of dry needling on gastrocnemius muscle stiffness and strength in participants with latent trigger points

Abnormal muscle stiffness is a potential complication after injury and identifying interventions that modify muscle stiffness may be useful to promote recovery. The purpose of this study was to identify the short-term effects of dry needling (DN) on resting and contracted gastrocnemius muscle stiffness and strength of the triceps surae in individuals with latent myofascial trigger points (MTrPs). In this randomized controlled trial, 52 individuals received two DN treatment sessions to latent MTrPs and 50 individuals received two sham needling sessions. Resting and contracted muscle stiffness were assessed both at the treatment site and a standardized central site in the medial gastrocnemius head immediately post-treatment and one week after the last session. There were significant group by time interactions for resting muscle stiffness at the site of the MTrP (p = .03), but not at the central site (p = .29). Post-needling between group comparison indicated that the DN group had significantly lower resting muscle stiffness at the site of the MTrP than the sham group after adjusting for baseline differences. There were no significant between group differences in contracted muscle stiffness or muscle strength. Identifying strategies that can reduce aberrant muscle stiffness may help to guide management of individuals with neuromuscular pain-related conditions.Level of evidence: Therapy, level 2.

Use of Muscle Feeding Arteries as Recipient Vessels for Soft Tissue Reconstruction in Lower Extremities.

Microsurgical free tissue transfer is still playing an important role in lower extremity reconstruction. Finding a suitable recipient artery for anastomosis is critical in the microsurgical procedure, especially in an extensive wound, or in a complex trauma combined with vascular injury. From April 2014 to March 2018, we retrospectively reviewed patients with traumatic/post-traumatic, oncologic, and electrical wounds in the lower extremity. Those treated with muscle feeding artery as recipient vessels were included. The latissimus dorsi (LD) muscle free flap, anterior lateral thigh (ALT) perforator free flap, and deep inferior epigastric perforator (DIEP) free flap were raised. The muscle feeding arteries to vastus lateral muscle and to medial head of gastrocnemius muscle, concomitant veins, and great saphenous vein were used as recipient vessels. Injuries included in the study were caused by tumour in 2 cases, car accident in 3 cases, crushing in 3 cases, burns in one case, and electrical injury in one case. The wound size varied from 14 cm × 6 cm to 30 cm × 20 cm. LD, ALT, and DIEP free flaps were used in 6, 3, and 4 patients, respectively. The muscle feeding arteries to medial head of gastrocnemius muscle, to sartorius muscle, and to vastus lateral muscle were used as recipient arteries in 4, 5, and one patient, respectively. Concomitant and great saphenous veins were used as recipient veins in 10 and 4 patients, respectively. Using the muscle feeding artery is feasible to avoid injury to the main artery and facilitate dissection and anastomoses, particularly when the wound is located proximal to the mid-third of the lower leg.

Relationship between Muscle Cross-Sectional Area by MRI and Muscle Thickness by Ultrasonography of the Triceps Surae in the Sitting Position.

The purpose of this study was to determine the differences in the muscle cross-sectional area (MCSA) of the triceps surae in the supine and sitting positions using magnetic resonance imaging (MRI), and the relationship between the MCSA of the triceps surae in the sitting position and muscle thickness (MT), assessed using MRI and ultrasonography, respectively. This study included 16 healthy young male participants. The measurement positions were 90° flexion of the knee joint and neutral position of the ankle joint in the sitting or supine positions. Using an open-configuration MRI system with a vertical gap and ultrasonography, we measured the MCSA and MT of the soleus muscle and the medial and lateral heads of the gastrocnemius muscle at three selected locations in the ventral part of the muscle. As a result, the 50% portion of the soleus muscle and the 25% and 50% portions of the gastrocnemius medial and lateral heads were higher in the sitting position than in the supine position. Furthermore, only 50% of the gastrocnemius medial head showed a correlation between the MCSA and MT. When using the MT of the triceps surae as an indicator of muscle volume in the sitting position, the muscle site should be considered.

Different Foot Positioning During Calf Training to Induce Portion-Specific Gastrocnemius Muscle Hypertrophy

Nunes, JP, Costa, BDV, Kassiano, W, Kunevaliki, G, Castro-e-Souza, P, Rodacki, ALF, Fortes, LS, and Cyrino, ES. Different foot positioning during calf training to induce portion-specific gastrocnemius muscle hypertrophy. J Strength Cond Res 34(8): 2347-2351, 2020-The aim of this study was to compare the changes in gastrocnemius muscle thickness (MT) between conditions such as which foot was pointed outward (FPO), foot was pointed inward (FPI), or foot was pointed forward (FPF). Twenty-two young men (23 ± 4 years) were selected and performed a whole-body resistance training program 3 times per week for 9 weeks, with differences in the exercise specific for calves. The calf-raise exercise was performed unilaterally, in a pin-loaded seated horizontal leg-press machine, in 3 sets of 20-25 repetitions for training weeks 1-3 and 4 sets for weeks 4-9. Each subject's leg was randomly assigned for 1 of the 3 groups according to the foot position: FPO, FPI, and FPF. Measurements with a B-mode ultrasound were performed to assess changes in MT of medial and lateral gastrocnemius heads. After the training period, there were observed increases in MT of both medial (FPO = 8.4%, FPI = 3.8%, and FPF = 5.8%) and lateral (FPO = 5.5%, FPI = 9.1%, and FPF = 6.4%) gastrocnemius heads, and significant differences for magnitude of the gains were observed between FPO and FPI conditions (p < 0.05). Positioning FPO potentiated the increases in MT of the medial gastrocnemius head, whereas FPI provided greater gains for the lateral gastrocnemius head. Our results suggest that head-specific muscle hypertrophy may be obtained selectively for gastrocnemius after 9 weeks of calf training in young male adults.

Posterior popliteal fossa S-shaped incision with double-window approach in treating posterior column of tibial plateau fractures

To evaluate the effectiveness and safty of posterior popliteal fossa S-shaped incision with double-window approach for the treatment of posterior column of tibial plateau fractures. A retrospective analysis was made on the clinical data of 13 patients with complex tibial plateau fractures involving both posteromedial and posterolateral columns between May 2015 and July 2017. There were 9 males and 4 females, aged 33-64 years (mean, 46.5 years). The causes of injury included traffic accident in 5 cases, falling from height in 2 cases, falling from electric bicycle in 4 cases, and falling because of skiing in 2 cases. The preoperative range of motion of the affected knees was (35.1±9.2)°. The time from injury to surgery was 7-19 days (mean, 13.3 days). All patients underwent a posterior popliteal fossa S-shaped incision through the window of medial heads of gastrocnemius muscle (medial window) and the window between medial and lateral head of gastrocnemius muscle (popliteal fossa window) approaches. After a good visual control of fracture reduction, both posteromedial and posterolateral columns of tibial plateau fractures were fixed with buttress plate respectively. Bone union, limb alignment, articular surface, and range of motion were estimated after operation. The American Hospital for Special Surgery (HSS) score was used to evaluate functional outcomes of knees. After operation, 1 patient had fat liquefaction and dehiscence of incision, which healed after expanding the wound; the other patients' incisions healed by first intention, and no vascular or nerve injury occurred during operation. All the 13 patients were followed up 12-18 months (mean, 16 months). The X-ray films showed that all patients obtained good fracture unions, the fracture healing time was 14-22 weeks (mean, 18 weeks). At 12 months after operation, the articular surface was smooth without collapse, and the knee range of motion was (109.5±13.6)°, showing significant difference when compared with preoperative value ( t=18.879, P=0.000). No complication of infection, re-displacement of fracture, or secondary varus/valgus deformity was observed during follow-up. The HSS score was 82-96 (mean, 89.6) at 12 months after operation, with the result of excellent in 10 cases and good in 3 cases. The posterior column fracture of tibial plateau involving both posteromedial and posterolateral columns treated by double-window approach through posterior popliteal fossa S-shaped incision is safe and effective, with satisfactory results and good recovery of knee joint function.

Cosine tuning determines plantarflexors' activities during human upright standing and is affected by incomplete spinal cord injury.

Plantarflexors such as the soleus (SOL) and medial gastrocnemius (MG) play key roles in controlling bipedal stance; however, how the central nervous system controls the activation levels of these plantarflexors is not well understood. Here we investigated how the central nervous system controls the plantarflexors' activation level during quiet standing in a cosine tuning manner where the maximal activation is achieved in a preferred direction (PD). Furthermore, we investigated how spinal cord injury affects these plantarflexors' activations. Thirteen healthy adults (AB) and thirteen individuals with chronic, incomplete spinal cord injury (iSCI) performed quiet standing trials. Their body kinematics and kinetics as well as electromyography signals from the MG and SOL were recorded. In the AB group, we found that the plantarflexors followed the cosine tuning manner during quiet standing. That is, MG was most active when the ratio of plantarflexion torque to knee extension torque was ~2:-3, whereas SOL was most active when the ratio was ~2:1. This suggests that the SOL muscle, despite being a monoarticular muscle, is sensitive to both ankle plantarflexion and knee extension during quiet standing. The difference in the PDs accounts for the phasic activity of MG and for the tonic activity of SOL. Unlike the AB group, the MG's activity was similar to the SOL's activity in the iSCI group, and the SOL PDs were similar to those in the AB group. This result suggests that chronic iSCI affects the control strategy, i.e., cosine tuning, for MG, which may affect standing balance in individuals with iSCI.NEW & NOTEWORTHY Soleus muscle shows a tonic activity whereas medial gastrocnemius muscle shows a phasic activity during quiet standing. Cosine tuning and their preferred direction account for the different muscle activation patterns between these two muscles. In individuals with chronic incomplete spinal cord injury, the preferred direction of gastrocnemius medial head is affected, which may result in their deteriorated standing balance.

The ultrasonographic measurement of muscle thickness in sarcopenia. A prediction study

Sarcopenia is a common disease in the elderly. Although extensive research has been conducted on muscle mass and quality assessment tools, there are still certain drawbacks preventing their universal use. The aim of this study was the evaluation of the thickness of head, neck, upper and lower limb muscles measured with ultrasonography, as a potential predictory tool in sarcopenia. Prediction study. The Outpatient Sarcopenia Clinic of the Rehabilitation Department of the University Hospital of Patras. Ninety-four individuals (27 men and 67 women) with a mean age of 75.6 years (SD=6.6), referred for sarcopenia screening, participated in this study. The muscle thickness was measured with transverse and longitudinal ultrasound scans bilaterally. The thickness of the geniohyoid and medial head of gastrocnemius muscle in all ultrasound sections, and the thickness of the rectus femoris and vastus intermedius muscle, in specific sections, was found to be significantly decreased in patients with sarcopenia (P<0.05). The Receiver Operating Characteristic (ROC) curve analysis of the ultrasound muscle thickness measurements resulted in a significant association with sarcopenia. In the case of the geniohyoid muscle, the measured area under the ROC curve was found to be the highest (0.79). The optimal cut-off for the prediction of sarcopenia from the geniohyoid muscle was 0.65 cm with sensitivity equal to 75.0% and specificity equal to 66.7%. The results of this study have shown that the thickness of the neck and lower limb muscles measured ultrasonographically can be utilized in the prediction of sarcopenia with high sensitivity and specificity. The prevalence of sarcopenia in the geriatric population and the rehabilitation wards is reported to be high. Therefore, an easy, fast, low cost and with no risk, widely available method such as ultrasonography could be an extremely valuable tool for the screening and follow-up of sarcopenia.

The evaluation of the tendon and muscle changes of lower extremity in patients with acromegaly.

Although it is well known that acromegaly causes enlargement in the extremities, studies investigating the effects of acromegaly on tendons, muscles and soft tissue are limited. The aims of our study were to investigate tendons, the presence of enthesitis, soft tissue, muscle groups in terms of thickness and pennation angle (PA) which is an indicator of microstructure and strength of the muscle, of the lower extremities. Thirty-nine patients with acromegaly and thirty-nine healthy control subjects similar for age, sex and body mass index were enrolled. Lower extremity tendons, skin, muscle groups were evaluated by ultrasound. The thicknesses of heel skin, heel pad, plantar fascia and Achilles tendon were higher in acromegaly than the control group (p < 0.05). The incidence of Achilles enthesitis were increased in the acromegaly group (p < 0.05). The thicknesses of the gastrocnemius medial head, vastus medialis, lateralis muscles for both sides and the left rectus femoris muscle were found to be lower in the acromegaly patients than controls (p < 0.05). However, thicknesses of vastus intermedius, gastrocnemius lateral head and soleus were similar between the acromegaly and control groups (p > 0.05). PA values of the right and left vastus medialis and the right vastus lateralis were found to be decreased in the acromegaly group (p < 0.05). Myostatin levels were lower in acromegaly group (p < 0.05). Acromegaly may cause to an increase in tendon and soft tissue thickness, enthesitis formation, decrease in the thickness of some muscles, and deterioration in microstructures in lower extremity.

Human Locomotion Classification for Different Terrains Using Machine Learning Techniques.

Gait analysis on healthy subjects was performed based on surface electromyographic and acceleration sensor signal, implemented through machine learning approaches. The surface EMG and 3-axes acceleration signals have been acquired for 5 different terrains: level ground, ramp ascent, ramp descent, stair ascent, and stair descent. These signals were acquired from the tibialis anterior and gastrocnemius medial head muscles that correspond to dorsiflexion and plantar flexion, respectively. After feature extraction, these signals are fed to 5 conventional classifiers: linear discriminant analysis, k-nearest neighbors, decision tree, random forest, and support vector machine, that classify different terrains for human locomotion. We compared the classification results for the above classifiers with deep neural network classifier. The objective was to obtain the features and classifiers that are able to discriminate between 5 locomotion terrains with maximum classification accuracy in minimum time by acquiring the signal from the least number of leg muscles. The results indicated that the support vector machine gives the highest classification accuracy of 99.20 (± 0.80)% for the dataset acquired from 15 healthy subjects. In terms of both accuracy and computation time, the support vector machine outperforms other classifiers.

Tracking of Time-Dependent Changes in Muscle Hardness After a Full Marathon.

Inami, T, Nakagawa, K, Yonezu, T, Fukano, M, Higashihara, A, Iizuka, S, Abe, T, and Narita, T. Tracking of time-dependent changes in muscle hardness after a full marathon. J Strength Cond Res 33(12): 3431-3437, 2019-We sought to identify changes in individual muscle hardness after a full marathon and to track time-dependent changes using ultrasound strain elastography (SE). Twenty-one collegiate marathon runners were recruited. Muscle hardness (i.e., strain ratio, SR) was measured using SE for the rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF) long head, tibialis anterior (TA), gastrocnemius medial (GM) head, and soleus (SOL) muscles at the following time points: pre (PRE), immediately post (POST), day-1 (D1), day-3 (D3), and day-8 (D8), after a full marathon. We found that the SR decreased after the full marathon (i.e., the muscle became harder), and that the lowest SR across all measured muscles was observed on D1. Although there was no difference in the magnitude of change in SR between the muscles of the thigh, that of the MG and SOL were significantly larger than that of the TA. Muscle hardness in the vastus lateralis, biceps femoris, and SOL recovered at D8 (i.e., nonsignificant difference from PRE), whereas recovery of rectus femoris and gastrocnemius medial hardness at D8 was not observed. Thus, the degree of change in muscle hardness does not occur uniformly within the lower extremity muscles. In particular, changes in muscle hardness of the TA after a full marathon are small compared with other muscles and time-dependent changes in each muscle vary during recovery. The features of muscle hardness identified in this study will be useful for coaches when mentoring runners on proper forms and for training advisers and therapists who seek to address deficiencies in running.

Regional Elastic Properties of the Achilles Tendon Is Heterogeneously Influenced by Individual Muscle of the Gastrocnemius.

Background Anatomical studies and the mechanical property studies showed that there is a strong correlation between Achilles tendon (AT) elasticity and individual gastrocnemius muscle (the medial head of gastrocnemius (MG) and the lateral head of gastrocnemius (LG)) elasticity. Limited ankle dorsiflexion range of motion has been correlated with decreased flexibility of the MG/LG/AT complex. However, no studies have been conducted to examine the exact correlation between the Achilles tendon and the individual muscle of the gastrocnemius. Purposes The purposes of the present study were (1) to evaluate intra- and interoperator reliabilities of elastic property measurements in the gastrocnemius muscle-Achilles tendon complex by using the shear wave elastography (SWE) and (2) to examine the correlation between the regional elastic properties of the AT and the individual muscle of the gastrocnemius. Methods Twenty healthy subjects (mean age: 22.50 (3.02) years) were recruited in this study. The elastic properties of the AT and the individual muscle of the gastrocnemius were quantified using the SWE. Findings The SWE has comparatively high reliability in quantifying the elastic properties of the muscle-tendon range from good to excellent. The intraoperator ICC of the gastrocnemius muscle-Achilles tendon complex was 0.77 to 0.95, while the interoperator ICC was 0.76 to 0.94. The minimal detectable change (MDC) of the muscle was 1.72 kPa, while the AT was 32.90 kPa. A significant correlation was found between the elastic modulus of AT and the elastic modulus of the MG (r = 0.668 and p = 0.001 at the relaxing position and r = 0.481 and p = 0.032 at the neutral position). Conclusions The SWE has the potential to assess localized changes in muscle-tendon elastic properties, provide more intuitive relations between elastic properties of the muscle tendon and function, and evaluate the therapeutic effect of the muscle tendon. A significant correlation between the AT and the MG was found, and it may provide a new treatment idea (targeted to the tight muscle heads) for the clinical setting to treat subjects with AT disorders.

Nerve dysfunction leads to muscle morphological abnormalities in chronic inflammatory demyelinating polyneuropathy assessed by MRI.

Neuropathic features of chronic inflammatory demyelinating polyneuropathy (CIDP) have been well documented, however very little is known about the implication of this neuropathy on skeletal muscle, and whether nerve lesions in CIDP lead to uniform disruptions in skeletal muscles. In this study, we assessed the triceps surae complex, using magnetic resonance imaging (MRI) in a group (n = 10) of CIDP patients compared with a healthy age-matched control group (n = 9). MRI (T1 and T2) of the leg musculature as well as plantar flexion strength measurements were obtained from both groups. CIDP patients compared with controls had ∼28% lower plantar flexion strength and ∼19% less total muscle volume (T1) of the triceps surae. When strength was normalized to fat corrected triceps surae volume CIDP patients were ∼30% weaker than controls. Relaxation times from the T2 scans were significantly longer in CIDP with the soleus, medial head of gastrocnemius and lateral head of gastrocnemius showing ∼37%, ∼38% and ∼26% longer relaxation times, respectively. CIDP patients were significantly weaker compared to controls and despite normalizing strength to total triceps surae contractile tissue volume this difference remained. CIDP patients had significantly longer T2 times, reflecting increased noncontractile tissue infiltration. These results indicate reduced muscle quantity and quality as a result of alterations in axonal function. Furthermore, when present study results are considered together with a prior report on the anterior compartment (Gilmore et al. 2016, Muscle Nerve 3:413-420), it is clear that both anterior and posterior leg compartments are affected similarly in CIDP despite different terminal nerve innervation and functional properties. Clin. Anat. 32:77-84, 2019. © 2019 Wiley Periodicals, Inc.

The impact of exposure to immersive virtual reality on spatiotemporal gait parameters in healthy participants: a preliminary study

Following lower limb injury, some patients are not able to walk at full weight bearing and may require body weight support for ambulation during the early stages of rehabilitation. The aim of the present study was to investigate how various degrees of reduced effective body weight in a Lower Body Positive Pressure Treadmill (LBPPT), affects muscle activation levels during walking. Twelve healthy participants were instructed to walk at 2.5 km/h and 3.6 km/h on a LBPPT that provided a reduced effective body weight equivalent to 100%, 80%, 60%, 40%, and 20% of their individual body mass. Electromyography data were recorded during 20 gait cycles, from seven lower limb muscles, and segmented into a mean envelope by computing root mean square values. A two-way repeated measures ANOVA was used to test for differences in the highest root mean square value obtained, with walking speed and fractional reduction in effective body weight as factors. Significant decreases in EMG amplitude were identified in the following muscles as a result of reduced effective body weight: Vastus Medialis, Vastus Lateralis, Soleus, Gastrocnemius Medial and Lateral head (p ≤ 0.05). For Tibialis Anterior, significant reductions in EMG amplitude were only observed when effective body weight was reduced to 40% or less at a walking speed of 2.5 km/h (p ≤ 0.05). The EMG amplitude for Tibialis Anterior at 3.6 km/h and Biceps Femoris at both speeds remained unaffected at all fractional reductions (p ≥ 0.05). These findings suggests that the muscles of the lower limb respond differently to the body weight support provided by the LBPPT during walking, with the extensor muscles of the knee and ankle displaying decreased muscle activation, and the Tibialis Anterior and Biceps Femoris displaying minimal to no changes in muscle activation.

Proximal Ultrasound-Guided Gastrocnemius Recession: A New Ultra-Minimally Invasive Surgical Technique

Selective proximal recession of the medial gastrocnemius head has clear advantages over other approaches and can be performed as a single or combined open procedure for many indications. The purpose of this study was to evaluate the safety and efficacy of a new technique based on ultrasound-guided ultraminimally invasive proximal gastrocnemius recession. We performed a pilot study with 16 cadavers to ensure that the technique was effective and safe; we then prospectively performed gastrocnemius recession in 12 patients (23 cases) with gastrocnemius contracture associated with other indications. We evaluated pre- and postprocedure dorsiflexion, clinical outcomes (based on the visual analog scale and American Orthopedic Foot and Ankle Society scores), and potential complications. We achieved effective release of the proximal medial gastrocnemius tendon in all cases, with no damage to other tissue. Ankle dorsiflexion increased 12° (range 6° to 18°) (p = .05) and was maintained throughout follow-up. The mean preoperative visual analog scale score was 7 (range 5 to 9), which improved to 1 (range 0 to 2) (p = .01). The American Orthopedic Foot and Ankle Society Ankle-Hindfoot Score improved from a mean of 25 (range 20 to 40) to 85 (range 80 to 100) at 6 months and 90 at 12 months (p = .01). No major complications were observed. We considered the technique to be safe and effective for ultrasound-guided ultraminimally invasive proximal-medial gastrocnemius recession using a 1-mm incision in vivo. This novel technique is an alternative to open techniques, with encouraging results and with the potential advantages of reducing pain and obviating lower limb ischemia and deep anesthesia, thus decreasing complications and contraindications and accelerating recovery, although further studies are required.