Soleus Research Articles

Asynchronous motion of the gastrocnemius and soleus muscles in a type 2B lesion.

Asynchronous motion of the gastrocnemius and soleus muscles in a type 2B lesion.

368P Ankle contractures in Duchenne muscular dystrophy: using real world data to study the influence of the gastrocnemius and soleus muscles on functional decline

368P Ankle contractures in Duchenne muscular dystrophy: using real world data to study the influence of the gastrocnemius and soleus muscles on functional decline

Synchronous motion of the gastrocnemius and soleus muscles in a type 3 lesion. US, ultrasound.

Synchronous motion of the gastrocnemius and soleus muscles in a type 3 lesion. US, ultrasound.

Asynchronous motion of the gastrocnemius and soleus muscles by MRI in a type 4 lesion.

Asynchronous motion of the gastrocnemius and soleus muscles by MRI in a type 4 lesion.

How does prolonged tennis playing affect lower limb muscles' activity during first and second tennis serves?

We examined the effect of prolonged tennis playing on lower limb muscles' activity during the execution of first and second tennis serves. Ten male competitive tennis players executed five first and second serves before (pretest) and after (posttest) a 3-h tennis match. Surface electromyographic (EMG) activity of four lower limb muscles (vastus lateralis, rectus femoris, gastrocnemius lateralis, and soleus muscles) on each leg was recorded along with maximum ball velocity measured by a radar gun and peak vertical forces recorded by a force platform. For the vastus lateralis, gastrocnemius lateralis, and soleus muscles of the left leg as well as the vastus lateralis muscle of the right leg, EMG amplitude decreased from pre- to posttests (p≤0.033). These reductions in the EMG signal were generally more pronounced in the first serve (i.e., ranging from -10% to -40%) compared to the second serve (0% to -25%). Maximum ball velocity for both first (159±12 vs. 154±12km/h) and second (126±20 vs. 125±15km/h) serves remained unchanged from pre- to posttests (p=0.638) Similarly, peak vertical forces did not differ between pretest and posttest for both first (1.78±0.30 vs. 1.72±0.29 body weight) and second (1.62±0.25 vs. 1.75±0.23 body weight) serves (p=0.730). In conclusion, a 3-h tennis match led to decreased activation levels in various leg muscles during serves, particularly in first serves compared to second serves. Despite consistent maximum ball velocity and peak vertical forces, these reductions in EMG signals suggest that skilled tennis players may adopt compensatory strategies after prolonged play.

Differential Responses To Heat Stress On The Regeneration Of Injured Rat Soleus And Plantaris Muscles

Differential Responses To Heat Stress On The Regeneration Of Injured Rat Soleus And Plantaris Muscles

Transformative Deep Vein Thrombosis Prophylaxis With Sequential Compression Devices in the Care of Hospitalized Patients.

Deep vein thrombosis (DVT) is a critical complication and concern in hospitalized patients due to its significant morbidity and mortality. Given the complex and multifaceted pathophysiology surrounding DVT formation, patients who have had surgical interventions faced acute or chronic trauma and prolonged immobility are at substantially high risk. Identifying these risk factors early is essential for early intervention and prophylaxis. Current standard-of-care prophylaxis for DVT includes pharmacological agents such as anticoagulants, and recently, there has been an increase in the use of mechanical medical devices such as sequential compression devices (SCDs). Pharmacological prophylaxis, while shown to be effective in some patients, carries certain risks of complications such as bleeding. SCDs offer a safer and more effective approach for these patients. SCDs function by artificially replicating the "pumping mechanism" present in the soleus muscle to enhance venous return and reduce stasis. Various types of SCDs, namely intermittent pneumatic compression and graduated compression stockings, have demonstrated clinical efficacy when used as an adjunctive intervention with anticoagulant medications. This narrative review explores the pathophysiology, risk factors, and prophylactic measures for DVT, focusing on the use of SCDs as a non-pharmacological intervention. Through synthesizing evidence from various studies obtained from PubMed, MEDLINE, and Cochrane Library and evaluating the benefits and limitations of SCD use, this review highlights the need for tailored prophylactic strategies, considering patient-specific risk factors and preferences.

Estimation of the Achilles tendon twist invivo by individual triceps surae muscle stimulation.

The Achilles tendon (AT) is composed of three distinct subtendons, each arising from one of the three heads of the triceps surae muscles: gastrocnemius medialis (GM), gastrocnemius lateralis (GL), and soleus (SOL). These subtendons exhibit a twisted structure, classified as low (Type I), medium (Type II), and high (Type III) twist, based on cadaveric studies. Nevertheless, the invivo investigation of AT twist is notably scarce, resulting in a limited understanding of its functional significance. The aim of this study was to give insights into the complex 3D AT structure invivo. A total of 30 healthy participants underwent individual stimulation of each of the triceps surae muscles at rest with the foot attached to the pedal of an isokinetic dynamometer. Ultrasound images were captured to concomitantly examine the displacement of the superficial, middle and deep AT layers. SOL stimulation resulted in the highest AT displacement followed by GM and GL stimulation. Independent of the muscle stimulated, non-uniformity within the AT was observed with the deep layer exhibiting more displacement compared to the middle and superficial layers, hence important inter-individual differences in AT displacement were noticeable. By comparing these individual displacement patterns during targeted stimulations with insights from cadaveric twist classifications on each subtendon area, our classification identified 19 subjects with a 'low' twist and 11 subjects with a 'high' twist. These findings enable us to move beyond cadaveric studies and relate the twisted microstructure of the AT invivo to its dynamic behaviour.

Impacts of endurance training and crocin supplementation on the apoptotic pathways in rat skeletal muscle following doxorubicin administration

Background and aims: Doxorubicin (DOX), in addition to its anti-cancer properties, causes toxicity and increases the apoptosis of healthy tissues. The objective of the current research was to explore the concurrent influence of an eight-week aerobic training regimen combined with crocin supplementation on the apoptosis induced by DOX within the soleus muscle tissue of male rodents. Methods: In this study, a cohort of 40 male Wistar rats, each weighing between 200 and 220 g and approximately 8 weeks old, were systematically distributed into five distinct experimental clusters, including a healthy control (normal saline) and a patient control (intraperitoneal injection of 2 mg/kg of DOX ). The other clusters were DOX-exercise (intraperitoneal injection of 2 mg/kg of DOX with eight weeks of treadmill/5 days a week), DOX-crocin (intraperitoneal injection of 2 mg/kg) 2 kg of DOX along with 10 mg/kg of crocin extract/8 weeks), and DOX-exercise-crocin. Results: The administration of DOX was associated with a notable elevation in Bax and a reduction in Bcl-2 expression (P=0.001 and P=0.001). In contrast, engaging in eight weeks of aerobic exercise, ingesting crocin, or a synergistic approach combining both interventions resulted in a marked upregulation of Bcl-2 expression (P=0.001). This combined treatment also led to a significant diminution in the Bax mRNA (P=0.006) and a decrease in the Bax/Bcl-2 ratio (P=0.001) within the soleus muscle tissue of male rodents subjected to DOX exposure. Conclusion: Aerobic exercise with crocin supplementation could inhibit apoptosis caused by DOX in the soleus muscle of male rats.

Effect of Isoflavone on Muscle Atrophy in Ovariectomized Mice.

Sarcopenia, characterized by muscle mass decline due to aging or other causes, is exacerbated by decreased estrogen levels after menopause in women. Isoflavones, a class of flavonoids acting on estrogen receptors, may have beneficial effects on metabolic disorders. We examined these effects in ovariectomized mice fed a high-fat, high-sucrose diet (HFHSD). At 7 weeks old, female C57BL6/J mice (18-20 g, n = 12) underwent bilateral ovariectomy (OVX), and were then fed a high-fat, high-sucrose diet starting at 8 weeks of age. Half of the mice received isoflavone water (0.1%). Metabolic analyses, including glucose and insulin tolerance tests, were conducted. Muscle analysis involved grip strength assays, next-generation sequencing, quantitative RT-PCR, and western blotting of skeletal muscle after euthanizing the mice at 14 weeks old. Additionally, 16S rRNA gene sequence analysis of the gut microbiota was performed. The results demonstrated that isoflavone administration did not affect body weight, glucose tolerance, or lipid metabolism. In contrast, isoflavone-treated mice had higher grip strength. Gene expression analysis of the soleus muscle revealed decreased Trim63 expression, and western blotting showed inactivation of muscle-specific RING finger protein 1 in isoflavone-treated mice. Gut microbiota analysis indicated higher Bacteroidetes and lower Firmicutes abundance in the isoflavone group, along with increased microbiota diversity. Gene sets related to TNF-α signaling via NF-κB and unfolded protein response were negatively associated with isoflavones. Isoflavone intake alters gut microbiota and increases muscle strength, suggesting a potential role in improving sarcopenia in menopausal women.

Transcutaneous spinal cord stimulation phase-dependently modulates spinal reciprocal inhibition induced by pedaling in healthy individuals.

Reciprocal inhibition (RI) between leg muscles is crucial for smooth movement. Pedaling is a rhythmic movement that can increase RI in healthy individuals. Transcutaneous spinal cord stimulation (tSCS) stimulates spinal neural circuits by targeting the afferent fibers. Pedaling with simultaneous tSCS may modulate the plasticity of the spinal neural circuit and alter neural activity based on movement and muscle engagement. This study investigated the RI changes after pedaling and tSCS and determined the phase of pedaling in which tSCS should be applied for optimal RI modulation in healthy individuals. Eleven subjects underwent three interventions: pedaling combined with tSCS during the early phase of lower extension (phase 1), pedaling combined with tSCS during the late phase of lower flexion (phase 4) of the pedaling cycle, and pedaling combined with sham tSCS. The RI from the tibialis anterior to the soleus muscle was assessed before, immediately after, 15min, and 30min after the intervention. RI increased immediately after phase 4 and pedaling combined with sham tSCS, whereas no changes were observed after phase 1. These results demonstrate that tSCS modulates RI changes induced by pedaling in a stimulus phase-dependent manner in healthy individuals. However, the mechanism involved in this intervention needs to be explored to achieve higher efficacy.

The LEAP2 Response to Cancer-Related Anorexia-Cachexia Syndrome in Male Mice and Patients.

The hormone ghrelin serves a protective role in cancer-related anorexia-cachexia syndrome (CACS)-a condition in which plasma levels of ghrelin rise, its administration lessens CACS severity, and experimentally reduced signaling by its receptor (GHSR) worsens fat loss and anorexia and accelerates death. Yet, actions for the related hormone liver-expressed antimicrobial peptide-2 (LEAP2), which is an endogenous GHSR antagonist, are unexplored in CACS. Here, we found that plasma LEAP2 and LEAP2/ghrelin ratio were lower in Lewis lung carcinoma (LLC) and RM-9 prostate cancer CACS mouse models. Ghrelin deletion exaggerated losses of tumor-free body weight and fat mass, reduced food intake, reduced soleus muscle weight, and/or lowered grip strength in LLC or RM-9 tumor-bearing mice. LEAP2 deletion lessened reductions in tumor-free body weight and fat mass and increased food intake in LLC or RM-9 tumor-bearing mice. In a 55-subject cohort of patients with CACS or weight-stable cancer, the plasma LEAP2/total ghrelin ratio was negatively correlated with 6-month weight change preceding blood collection. These data demonstrate that ghrelin deletion exacerbates CACS in the LLC and RM-9 tumor-bearing mouse models while contrastingly, LEAP2 deletion reduces measures of CACS in these tumor-bearing mouse models. Further, they suggest that lower plasma LEAP2/ghrelin ratio protects against worsened CACS.

Remobilization with whole-body vibration improves functionality, histomorphometric parameters, and AQP1 expression in the soleus muscle of Wistar rats.

Whole-body vibration (WBV) is used to enhance physical performance in sports and rehabilitation. The present study analyzed the effects of remobilization with WBV on the soleus muscle of Wistar rats. Twenty-eight animals were separated into four experimental groups (n = 7): CON (control); IM (immobilized); FR (immobilization and free remobilization); and WBV (immobilization and remobilization with WBV). The immobilization of the pelvic limb was carried out according to the standard protocol using a plaster cast for 15 days. For remobilization with WBV, a Frequency of 60 Hz was applied for 10 min, five days a week, for two weeks. After the remobilization period, the animals were euthanized, and the right soleus muscle was dissected followed by processing for histomorphometric analysis and immunolocalization of Aquaporin 1 (AQP1). We observed a reduced larger diameter in IM compared to CON, with restored values in WBV. For the estimation of connective tissue, a significant increase was observed in the immobilized groups, while a reduction was noted in the remobilized groups. AQP1 expression decreased significantly in IM and increased in WBV. Immobilization caused morphofunctional damage to the soleus muscle, and remobilization with WBV is efficient and offers advantages over free remobilization.

Effects of Bifidobacterium-Fermented Milk on Obesity: Improved Lipid Metabolism through Suppression of Lipogenesis and Enhanced Muscle Metabolism.

Obesity is a major global health concern. Studies suggest that the gut microflora may play a role in protecting against obesity. Probiotics, including lactic acid bacteria and Bifidobacterium, have garnered attention for their potential in obesity prevention. However, the effects of Bifidobacterium-fermented products on obesity have not been thoroughly elucidated. Bifidobacterium, which exists in the gut of animals, is known to enhance lipid metabolism. During fermentation, it produces acetic acid, which has been reported to improve glucose tolerance and insulin resistance, and exhibit anti-obesity and anti-diabetic effects. Functional foods have been very popular around the world, and fermented milk is a good candidate for enrichment with probiotics. In this study, we aim to evaluate the beneficial effects of milks fermented with Bifidobacterium strains on energy metabolism and obesity prevention. Three Bifidobacterium strains (Bif-15, Bif-30, and Bif-39), isolated from newborn human feces, were assessed for their acetic acid production and viability in milk. These strains were used to ferment milk. Otsuka-Long-Evans Tokushima Fatty (OLETF) rats administered Bif-15-fermented milk showed significantly lower weight gain compared to those in the water group. The phosphorylation of AMPK was increased and the expression of lipogenic genes was suppressed in the liver of rats given Bif-15-fermented milk. Additionally, gene expression related to respiratory metabolism was significantly increased in the soleus muscle of rats given Bif-15-fermented milk. These findings suggest that milk fermented with the Bifidobacterium strain Bif-15 can improve lipid metabolism and suppress obesity.

Melatonin protects against sarcopenia in middle-aged mice.

Sarcopenia is a common age-related disease. Melatonin (MEL) is an age-related endocrine hormone, which displays a crucial role in resisting oxidative stress during aging. Importantly, the antioxidant properties of MEL can be mediated by mitochondria. Therefore, we wondered whether MEL could mitigate oxidative stress caused by mitochondria in sarcopenia. The middle-aged mice were administered 5 mg/kg/d and 10 mg/kg/d of MEL for 2 months. Young mice were used as the control group. After treatment with MEL, the grip strength of the fore/hind limbs, running time, and distance were elevated, and the weights of the gastrocnemius (GA), tibialis anterior (TA), extensor digitorum longus (EDL), and soleus (SOL) were enhanced in middle-aged mice. Additionally, MEL was observed to alleviate histological damage and increase the cross-sectional area of muscle fibers in GA tissues of middle-aged mice. Furthermore, following MEL treatment, there was an increase in the percentage and size of normal mitochondria as well as mtDNA copy number but a reduction in the levels of malondialdehyde (MDA), protein carbonyl, and reactive oxygen species (ROS) in the GA tissues of middle-aged mice. At the molecular level, MEL repressed the levels of ATROGIN-1, muscle RING-finger protein-1 (MURF-1), and the ratio of p-P38/P38, but elevated the expression of cytochrome c oxidase subunit 4 (COX4), cystatin C (CYTC), nuclear respiratory factor 1 (NRF-1), mitochondrial transcription factor A (TFAM), and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) in the GA tissues of middle-aged mice. Importantly, 10 mg/kg MEL was more efficacious in the treatment of sarcopenia than 5 mg/kg MEL. MEL attenuates sarcopenia in middle-aged mice, and the mechanism may relate to mitochondria-induced oxidative stress and the PGC-1α/TFAM pathway.

Is the Silfverskiöld Test a valid tool for evaluating calf muscles spastic overactivity in patients with stroke? A retrospective observational study.

Spastic equinus (plantar flexed) foot is a common postural pattern in patients who suffer from post-stroke spasticity. To date, some clinicians use the Silfverskiöld Test in their practice to differentiate between gastrocnemius and soleus muscle overactivity in patients with spastic equinus (plantar flexed) foot. This use of the Silfverskiöld Test goes beyond its original aim, which was to distinguish isolated gastrocnemius contracture in patients with equinus deformity. The aim of this study was to investigate the Silfverskiöld Test validity for evaluating spastic equinus (plantar flexed) foot (i.e., differentiation between gastrocnemius and soleus muscle overactivity) by checking its outcome against those of selective diagnostic nerve block of tibial motor nerve branches to the soleus, gastrocnemius and tibialis posterior muscles. The design of the study was retrospective observational. The study was set in a university hospital. Sixty-seven adult stroke patients with spastic equinus (plantar flexed) foot. Each patient underwent selective diagnostic nerve block of tibial motor nerve branches to the soleus, gastrocnemius and tibialis posterior muscles. All patients were evaluated before diagnostic nerve block by means of the Silfverskiöld Test which was considered positive when ankle joint passive dorsiflexion was greater with the knee flexed than extended. Furthermore, they were assessed before and after nerve block by means of the modified Ashworth Scale and the Tardieu Scale. Our sample included 41 males and 26 females (mean age 57.6 years) suffering from spastic equinus (plantar flexed) foot due to chronic stroke (mean time from onset 2.4 years). Forty-eight patients out of 67 presented with positive Silfverskiöld Test. The χ2 test showed no association between the Silfverskiöld Test and spastic overactivity of the gastrocnemius (P=0.253), soleus (P=0.605) and tibialis posterior (P=0.462) muscles as evaluated by serial selective diagnostic block of the tibial nerve motor branches. Our findings do not support the Silfverskiöld Test as a valid tool for evaluating spastic equinus (plantar flexed) foot to differentiate between gastrocnemius, soleus and tibialis posterior spastic muscle overactivity in adult patients with stroke. The choice for an appropriate management of spastic equinus (plantar flexed) foot in adults with stroke should not be mainly defined on the base of Silfverskiöld Test.

Achilles tendon morpho-mechanical parameters are related to triceps surae motor unit firing properties.

Recent studies combining high-density surface electromyography (HD-sEMG) and ultrasound imaging have yielded valuable insights into the relationship between motor unit activity and muscle contractile properties. However, limited evidence exists on the relationship between motor unit firing properties and tendon morpho-mechanical properties. This study aimed to determine the relationship between triceps surae motor unit firing properties and the morpho-mechanical properties of the Achilles tendon (AT). Motor unit firing properties [i.e. mean discharge rate (DR) and coefficient of variation of the interspike interval (COVisi)] and motor unit firing-torque relationships [cross-correlation between cumulative spike train (CST) and torque, and the delay between motor unit firing and torque production (neuromechanical delay)] of the medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (SO) muscles were assessed using HD-sEMG during isometric plantarflexion contractions at 10% and 40% of maximal voluntary contraction (MVC). The morpho-mechanical properties of the AT (i.e. length, thickness, cross-sectional area, and resting stiffness) were determined using B-mode ultrasonography and shear-wave elastography. Multiple linear regression analysis showed that at 10% MVC, the DR of the triceps surae muscles explained 41.7% of the variance in resting AT stiffness. In addition, at 10% MVC, COVisi SO predicted 30.4% of the variance in AT length. At 40% MVC, COVisi MG and COVisi SO explained 48.7% of the variance in AT length. Motor unit-torque relationships were not associated with any morpho-mechanical parameter. This study provides novel evidence of a contraction intensity-dependent relationship between motor unit firing parameters of the triceps surae muscle and the morpho-mechanical properties of the AT. NEW & NOTEWORTHY By employing HD-sEMG, conventional B-mode ultrasonography, and shear-wave elastography, we showed that the resting stiffness of the Achilles tendon is related to mean discharge rate of triceps surae motor units during low-force isometric plantarflexion contractions, providing relevant information about the complex interaction between rate coding and the muscle-tendon unit.

Effects of ankle joint degree of freedom of knee–ankle–foot orthoses on loading patterns and triceps surae muscle activity on the paretic side in individuals with subacute severe hemiplegia: a retrospective study

BackgroundIndividuals with subacute severe hemiplegia often undergo alternate gait training to overcome challenges in achieving walking independence. However, the ankle joint setting in a knee–ankle–foot orthosis (KAFO) depends on trunk function or paralysis stage for alternate gait training with a KAFO. The optimal degree of ankle joint freedom in a KAFO and the specific ankle joint conditions for effective rehabilitation remain unclear. Therefore, this study aimed to investigate the effects of different degrees of freedom of the ankle joint on center-of-pressure (CoP) parameters and muscle activity on the paretic side using a KAFO and to investigate the recommended setting of ankle joint angle in a KAFO depending on physical function.MethodsThis study included 14 participants with subacute stroke (67.4 ± 13.3 years). The CoP parameters and muscle activity of the gastrocnemius lateralis (GCL) and soleus muscles were compared using a linear mixed model (LMM) under two ankle joint conditions in the KAFO: fixed at 0° and free ankle dorsiflexion. We confirmed the relationship between changes in CoP parameters or muscle activity under different conditions and physical functional characteristics such as the Fugl–Meyer Assessment of Lower Extremity Synergy Score (FMAs) and Trunk Impairment Scale (TIS) using LMM.ResultsAnterior–posterior displacement of CoP (AP_CoP) (p = 0.011) and muscle activity of the GCL (p = 0.043) increased in the free condition of ankle dorsiflexion compared with that in the fixed condition. The FMAs (p = 0.004) and TIS (p = 0.008) demonstrated a positive relationship with AP_CoP. A positive relationship was also found between TIS and the percentage of medial forefoot loading time in the CoP (p < 0.001).ConclusionsFor individuals with severe subacute hemiplegia, the ankle dorsiflexion induction in the KAFO, which did not impede the forward tilt of the shank, promotes anterior movement in the CoP and muscle activity of the GCL. This study suggests that adjusting the dorsiflexion mobility of the ankle joint in the KAFO according to improvement in physical function promotes loading of the CoP to the medial forefoot.

Long-term effects of the chronic administration of doxorubicin on aged skeletal muscle: An exploratory study in mice

The widely used chemotherapeutic drug doxorubicin (DOX) has been associated with adverse effects on the skeletal muscle, which can persist for years after the end of the treatment. These adverse effects may be exacerbated in older patients, whose skeletal muscle might already be impaired by aging. Nonetheless, the mediators responsible for DOX-induced myotoxicity are still largely unidentified, particularly the ones involved in the long-term effects that negatively affect the quality of life of the patients. Therefore, this study aimed to investigate the long-term effects of the chronic administration of DOX on the soleus muscle of aged mice. For that and to mimic the clinical regimen, a dose of 1.5 mg kg−1 of DOX was administered two times per week for three consecutive weeks in a cumulative dose of 9 mg kg−1 to 19-month-old male mice, which were sacrificed two months after the last administration. Body wasting and the atrophy of the soleus muscle, as measured by a decrease in the cross-sectional area of the soleus muscle fibers, were identified as long-term effects of DOX administration. The atrophy observed was correlated with increased reactive oxygen species production and caspase-3 activity. An impaired skeletal muscle regeneration was also suggested due to the correlation between satellite cells activation and the soleus muscle fibers atrophy. Systemic inflammation, skeletal muscle energy metabolism and neuromuscular junction-related markers do not appear to be involved in the long-term DOX-induced skeletal muscle atrophy. The data provided by this study shed light on the mediators involved in the overlooked long-term DOX-induced myotoxicity, paving the way to the improvement of the quality of life and survival rates of older cancer patients.

Agonist-antagonist myoneural interface surgery on the proprioceptive reconstruction of rat hind limb

Currently, prosthesis users rely on visual cues to control their prosthesis. One reason for this is that prostheses cannot provide users with proprioceptive functional signals. For this reason, we propose an agonist-antagonist myoneural interface (AMI) surgery. We examined how this surgery affects the restoration of motor function and proprioceptive reconstruction in the hind limb of Sprague–Dawley rats. The procedure entails grafting the soleus muscle, suturing the two tendon ends of the soleus muscle, and anastomosing the tibial and common peroneal nerves to the soleus muscle. We found that, following surgery, AMI rats exhibited improved neurological repair, shorter walking swings, braking, propulsion, and stance times, and greater compound action potentials than control rats. This means that in rats with neurological impairment of the hind limb, the proposed AMI surgical method significantly improves postoperative walking stability and muscle synergy. AMI surgery may become an option for regaining proprioception in the lost limb.