Medial Gastrocnemius Research Articles

Influence of foot strike pattern on co-contraction around the ankle and oxygen uptake during running at 19 km/h.

This study investigated the coactivation of plantar flexor and dorsiflexor muscles and oxygen uptake during running with forefoot and rearfoot strikes at 15 and 19 km/h. We included 16 male runners in this study. The participants ran each foot strike pattern for 5 min at 15 and 19 km/h on a treadmill. During the running, respiratory gas exchange data and surface electromyographic (EMG) activity of the medial gastrocnemius (MG), lateral gastrocnemius (LG), soleus, and tibialis anterior muscles of the right lower limb were continuously recorded. The indices of oxygen uptake, energy expenditure (EE), and muscle activation were calculated during the last 2 min in each condition. During the stance phase of running at 15 and 19 km/h, activation of the tibialis anterior and MG muscles was lower and higher, respectively, with forefoot strike than with rearfoot strike. The foot strike pattern did not influence the oxygen uptake. These results suggest that the foot strike pattern has no clear effect on the oxygen uptake when running at 15 and 19 km/h. However, forefoot strike leads to plantar flexion dominance during co-contraction of the tibialis anterior and MG muscles, which are an antagonist and agonist for plantar flexion, respectively, during the stance phase.

Muscular Activation Levels of Subjects with Low Medial Longitudinal Arch During Single-Leg Squat and Single-Leg Balancing Exercises on Surfaces of Different Hardness.

The primary aim of this study is to examine the effect of the stiffness of rehabilitation material on muscle activation in individuals with low medial longitudinal arch. The secondary aim is to compare the effects of single-leg balancing and single-leg squat exercises on the activation of the muscles around the ankle in the same individuals. Twelve individuals with low medial longitudinal arch and 18 healthy control participants were included. Participants were asked to perform the single-leg balance and single-leg squat exercises on Theraband stability trainers of three different stiffness levels. Activation of the peroneus longus, peroneus brevis, tibialis anterior, medial and lateral gastrocnemius muscles during exercises was evaluated by surface electromyography. The single-leg balancing exercise performed on soft and very soft ground was more effective than single-leg squat in increasing the activation of the lateral gastrocnemius muscle in participants with a low medial longitudinal arch. It was determined that performing single-leg squat exercise on a very soft surface instead of hard ground caused more muscular activation in the peroneus brevis, tibialis anterior, and medial gastrocnemius in the same individuals. The exercise progression to be applied on different surfaces to increase the activation of the muscles around the ankle in individuals with a low medial longitudinal arch and in healthy individuals without a low medial longitudinal arch was different.

Quantifying Active and Passive Stiffness in Plantar Flexor Muscles Following Intermittent Maximal Isometric Contractions Using Shear Wave Elastography

ObjectiveThis study aimed: (i) to investigate the impact of fatigue, triggered by maximal isometric contraction exercises, on the active and passive stiffness of plantar flexors (PF), and (ii) to examine the relationship between changes in mechanical parameters and neuromuscular alterations after fatigue. MethodsA healthy cohort (n = 12; age = 27.3 ± 5.5 y; BMI = 24.4 ± 2.35 kg/m²) was instructed to perform 60 isometric contractions, each lasting 4 s with a 1-s rest interval, using an ergometer. Several measures were taken before and after the fatigue protocol. First, the stiffness of the PF-tendon complex (PFC) was quantified during passive ankle mobilization both during and after the fatigue protocol using the ergometer. Additionally, from shear wave elastography, the active and passive stiffness of the gastrocnemius medialis (GM) were measured during passive ankle mobilization and isometric maximal voluntary contraction (MVC), respectively. Finally, the peak torque and the rate of torque development (RFD) of PF were assessed during the MVC using the ergometer. Ankle muscle activities (surface electromyograph [SEMG]) were recorded during all evaluations using electromyography. ResultsAfter the fatigue protocol, the results revealed a decline in active stiffness, peak torque of PF, RFD and SEMG activity of the GM (p < 0.001). Furthermore, significant correlation was identified between the decrease of the peak torque of PF and the active stiffness of the GM (r = 0.6; p < 0.05). A decrease in the PFC stiffness (p < 0.001) and a decrease in the shear modulus of the GM at 20° (p < 0.001) were also observed. ConclusionIsometric fatiguing exercises modify the mechanical properties of both the contractile and elastic components. Notably, decreases in both passive and active stiffness may be critical for athletes, as these changes could potentially increase the risk of injury.

The effect of serial casting on medial gastrocnemius muscle architecture in children with idiopathic toe walking

The effect of serial casting on medial gastrocnemius muscle architecture in children with idiopathic toe walking

Dynamic behavior of the gastrocnemius medialis during functional power exercises in typically developing children

Dynamic behavior of the gastrocnemius medialis during functional power exercises in typically developing children

High-density EMG reveals atypical spatial activation of the gastrocnemius during walking in adolescents with Cerebral Palsy

Children with Cerebral Palsy (CP) exhibit less-selective, simplified muscle activation during gait due to injury of the developing brain. Abnormal motor unit recruitment, altered excitation-inhibition balance, and muscle morphological changes all affect the CP electromyogram. High-density surface electromyography (HDsEMG) has potential to reveal novel manifestations of CP neuromuscular pathology and functional deficits by assessing spatiotemporal details of myoelectric activity. We used HDsEMG to investigate spatial-EMG distribution and temporal-EMG complexity of gastrocnemius medialis (GM) muscle during treadmill walking in 11 adolescents with CP and 11 typically developed (TD) adolescents.Our results reveal more-uniform spatial-EMG amplitude distribution across the GM in adolescents with CP, compared to distal emphasis in TD adolescents. More-uniform spatial-EMG was associated with stronger ankle co-contraction and spasticity. CP adolescents exhibited a non-significant trend towards elevated EMG-temporal complexity. Homogenous spatial distribution and disordered temporal evolution of myoelectric activity in CP suggests less-structured and desynchronized recruitment of GM motor units, in combination with muscle morphological changes. Using HDsEMG, we uncovered novel evidence of atypical spatiotemporal activation during gait in CP, opening paths towards deeper understanding of motor control deficits and better characterization of changes in muscular activation from interventions.

The relation between macro- and microscopic muscle size parameters of the medial gastrocnemius in children with spastic cerebral palsy

The relation between macro- and microscopic muscle size parameters of the medial gastrocnemius in children with spastic cerebral palsy

Reliability of In Vivo Creatine-Weighted Chemical Exchange Saturation Transfer (CrCEST) MRI in Calf Skeletal Muscle of Healthy Volunteers at 3 T.

Skeletal muscle mitochondrial oxidative phosphorylation (mtOXPHOS) is important for ATP generation and its dysfunction leads to exercise intolerance. Phosphorus magnetic resonance spectroscopy (31P-MRS) is a useful, noninvasive technique for mtOXPHOS assessment but has limitations. Creatine-weighted chemical exchange saturation transfer (CrCEST) MRI is a potential alternative to assess muscle bioenergetics. To evaluate the interscan repeatability, intra- and interobserver reproducibility of CrCEST during mild plantar flexion exercise. Retrospective. Twenty healthy volunteers (age 37.6 ± 12.4 years, 11 females). 3 T/CEST imaging using gradient echo readout. τCrCEST (postexercise Cr recovery time) was assessed in two scans for each participant, following mild plantar flexion exercises targeting the medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (Sol) muscles. Three observers measured τCrCEST for interobserver reproducibility. Three readings by one observer were used to measure intraobserver reproducibility. Two scans were used for within-participant interscan repeatability. Paired t tests, intraclass correlation coefficient (ICC), and Pearson correlation were conducted. Bland-Altman plots were used to analyze the interobserver variability. A P-value of 0.05 was considered statistically significant. There was excellent intra- (ICC ) and interobserver (ICC ) reproducibility, with moderate interscan repeatability for τCrCEST in LG and MG (ICC ) and poor-to-moderate interscan repeatability in Sol (ICC ). Excellent interobserver reproducibility was confirmed by Bland-Altman plots (fixed bias P-value ). CrCEST MRI shows promise in assessing muscle bioenergetics by evaluating τCrCEST during mild plantar flexion exercise with reasonable reliability, particularly in LG and MG. 4 TECHNICAL EFFICACY: Stage 1.

Exploring the utility of ultrasound to assess disuse atrophy in different muscles of the lower leg.

Skeletal muscle is a highly plastic tissue crucial for many functions associated with whole-body health across the life course. Magnetic resonance imaging (MRI) is the current gold standard for measuring skeletal muscle size. However, MRI is expensive, and access to facilities is often limited. B-mode ultrasonography (U/S) has been proposed as a potential alternative to MRI for the assessment of muscle size. However, to date, no work has explored the utility of U/S to assess disuse muscle atrophy (DMA) across muscles with different atrophy susceptibility profiles, an omission which may limit the clinical application of previous work. To address this significant knowledge gap, 10 young men (22±years, 24.1±2.3kg/m2) underwent 15-day unilateral leg immobilization using a knee-brace and air boot. Cross-sectional area (CSA) and muscle thickness (MT) of the tibialis anterior (TA) and medial gastrocnemius (MG) were assessed via U/S before and after immobilization, with CSA and muscle volume assessed via MRI. With both muscles combined, there were good correlations between each U/S and MRI measure, both before (e.g., CSAMRI vs. MTU/S and CSAU/S: r=0.88 and 0.94, respectively, both P<0.0001) and after (e.g., VOLMRI vs. MTU/S and CSAU/S: r=0.90 and 0.96, respectively, both P<0.0001) immobilization. The relationship between the methods was notably stronger for MG than TA at each time-point (e.g., CSAMRI vs. MTU/S: MG, r=0.70, P=0.0006; TA, r=0.37, P=0.10). There was no relationship between the degree of DMA determined by the two methods in either muscle (e.g., TA pre- vs. post-immobilization, VOLMRI: 136±6 vs. 133±5, P=0.08; CSAU/S: 6.05±0.3 vs. 5.92±0.4, P=0.70; relationship between methods: r=0.12, P=0.75). Both MTU/S and CSAU/S provide comparable static measures of lower leg muscle size compared with MRI, albeit with weaker agreement in TA compared to MG. Although both MTU/S and CSAU/S can discern differences in DMA susceptibility between muscles, neither can reliably assess degree of DMA. Based on the growing recognition of heterogeneous atrophy profiles between muscles, and the topical importance of less commonly studied muscles (i.e., TA for falls prevention in older adults), future research should aim to optimize accessible methods to determine muscle losses across the body.

Relation between stretch and activation of the medial gastrocnemius muscle during gait in children with cerebral palsy compared to typically developing children

Stretch hyperreflexia is often a target for treatment to improve gait in children with spastic cerebral palsy (CP). However, the presence of stretch hyperreflexia during gait remains debated. Therefore, we assessed the relation between gastrocnemius medialis muscle-tendon stretch and muscle activation during gait in children with CP compared to typically developing (TD) children. 3D gait analysis including electromyography (EMG) and dynamic ultrasound was carried out to assess, respectively gastrocnemius medialis activation and fascicle, belly, and tendon stretch during treadmill walking. Musculotendon-unit stretch was also estimated using OpenSim. Ratios of EMG/peak lengthening velocities and accelerations were compared between CP and TD. Velocity and acceleration peaks prior to EMG peaks were qualitatively assessed. EMG/velocity and EMG/acceleration ratios were up to 500% higher for CP (n = 14) than TD (n = 15) for most structures. Increased late swing muscle activation in CP was often preceded by fascicle and musculotendon-unit peak lengthening velocity, and early stance muscle activation by peaks in multiple structures. Increased muscle activation in CP is associated with muscle-tendon stretch during gait. Concluding, late swing muscle activation in CP appears velocity-dependent, whereas early stance activation can be velocity- and acceleration-dependent. These insights into stretch reflex mechanisms during gait can assist development of targeted interventions.

Ultrasonographic measurements of gastro-soleus fascia thickness in midportion Achilles tendinopathy: A case-control study

BackgroundThe Achilles tendon is one of the thickest, largest, and strongest tendons in the human body. Biomechanically, the AT represents the conjoint tendon of the triceps surae muscle, placed in series with the plantar fascia (PF) to ensure force transmission from the triceps surae toward the toes during walking, running, and jumping. Commonly encountered in the diagnostic evaluation of heel pain, Achilles tendinopathy (AT) refers to a combination of pathological changes affecting the tendon itself often resulting from excessive repetitive stress and overuse. Nevertheless, increasing evidence demonstrates that structural alterations due to overuse or abnormal patterns of skeletal muscle activity are not necessarily restricted to the muscles or tendons but can also affect the fascial tissue. At the same time, there has been recent discussion regarding the role of the fascial tissue as a potential contributor to the pathophysiological mechanisms of the development of several musculoskeletal disorders including tendinopathies. To the best of our knowledge, ultrasound (US) imaging studies on the fascial structures related to the triceps surae complex, as well as their possible correlation with Achillodynia have never been presented in the current literature. MethodsIn the present study, a comparative US imaging evaluation of textural features of the suro-Achilleo-plantar complex was performed in 14 healthy controls and 14 symptomatic subjects complaining of midportion AT. The thickness of the Achilles tendon, paratenon, intermuscular fascia, and PF has been assessed with US. In addition, both groups underwent the Victorian Institute of Sport Assessment-Achilles (VISA-A), a disease-specific questionnaire that measures the severity of symptoms of AT. Correlations between quantitative ultrasound measures and VISA-A scores were determined through Pearson or Spearman's rho correlations. ResultsOur ultrasonographic findings revealed statistically significant differences (p<0.05) in Achilles tendon and paratenon thicknesses between AT patients and controls. No significant differences were observed between groups in PF at the calcaneal insertion as all mean measures were within the expected range of a normal PF on US imaging. In contrast, in tendinopathic subjects, the deep intermuscular fascia between medial gastrocnemius (MG) and soleus (SOL) muscles is significantly (p<0.01) and considerably thickened compared to those of healthy subjects. Moderate correlations exist between tendon and paratenon thicknesses (r= 0.54, p= 0.04) and between MG-SOL fascia and tendon thicknesses (r= 0.58, p= 0.03). Regarding symptom severity and US morphological findings, the Spearman ρ test showed no correlation. ConclusionsOur data demonstrate that, in symptomatic subjects, US alterations are not restricted to paratenon and intratendinous areas, but also affect upstream structures along the myofascial chain, resulting in thickening of the fascia interposed between MG and SOL muscles. Moreover, positive correlations were found between MG-SOL fascia thickening and abnormalities in AT, paratenon, and symptom severity. Thus, US alterations in the fascial system should be interpreted within the clinical context of patients with AT as they may in turn represent important predictors of subsequent clinical outcomes and could help healthcare professionals and clinicians to refine non-operative treatment strategies and rehabilitation protocols for this disease.

Eight sessions of transcranial electrical stimulation for postural response in people with Parkinson’s disease: A randomized trial

BackgroundImpairments in postural responses to perturbation are common in people with Parkinson’s disease (PwPD) and lack effective treatment. We recently showed that a single session of transcranial direct current stimulation (tDCS) promotes acute improvement of postural response to perturbation in PwPD. However, the effects of multiple tDCS sessions remain unclear. Research questionWhat is the efficacy of eight sessions of anodal tDCS on postural responses to external perturbation in PwPD? MethodsTwenty-two PwPD participated in this randomized, double-blind, parallel-arm, and sham-controlled study. Participants were randomly distributed into active (a-tDCS; n=11) or sham stimulation (s-tDCS; n=11). Eight tDCS sessions were applied over the primary motor cortex (M1), with the a-tDCS group receiving 2 mA for 20 minutes. Postural responses to external perturbations were assessed before, 48 hours after, and one month after (follow-up) the completion of tDCS sessions. Primary outcome measures included the onset latency of medial gastrocnemius (MG) muscle and range of center of pressure. Secondary outcomes included electromyography and CoP parameters, and prefrontal cortex (PFC) activity. ResultsANOVA revealed a trend for Group*Moment interaction for MG onset latency (p=0.058). a-tDCS tended to have shorter MG onset latency at post-test (p=0.040; SRM = −0.63) compared to pre-test. For the secondary outcomes, only a-tDCS decreased the time taken to recover balance after the perturbation at post-test and follow-up compared to pre-test (both p<0.001; SRM=-1.42 and −1.53, respectively). Also, only a-tDCS demonstrated lower PFC activity at post-test compared to pre-test (p=0.017; SRM = −0.82) and follow-up (p=0.001). SignificanceEight sessions of tDCS over M1 improved postural response to perturbation in PwPD. Some benefits lasted for at least a month. Neuromuscular and behavioral changes observed after the intervention were accompanied by decreased PFC activity (executive-attentional control), suggesting that tDCS applied over M1 can improve movement automaticity.

Muscle Mitochondrial Capacity Is Impaired Immediately Following Maximal Exercise.

This study measured the time course mVO2max following both maximal and submaximal exercise. Healthy male and female participants were tested (n = 12 maximal and n = 8 submaximal exercise). A NIRS device was placed on the left medial gastrocnemius. Participants performed either one minute of maximal, rapid (~2 Hz), or submaximal (~0.37 Hz) plantar flexion exercise on a custom pneumatic ergometer. mVO2max was measured before and immediately after exercise. mVO2max measurements consisted of four incomplete recovery curves of muscle metabolism taken after 30 seconds of electrical muscle stimulation except in the first post-exercise trial. The four recovery curves were collected 50-, 156-, 260-, and 366-seconds post-exercise, each producing a mVO2max rate constant. After maximal exercise muscle acceleration decreased to 52 + 18% (p = 0.001) of pre-values. mVO2max was reduced from the pre-exercise mean at the first post-trial (2.16 + 0.44 min-1 to 1.21 + 0.52 min -1, p < 0.001). The fourth trial showed recovery from the first (2.2 + 0.46 min-1 vs 1.21 + 0.52 min-1, p < 0.001) and was not significantly different from pre-exercise values (2.2 + 0.46 min-1 vs 2.16 + 0.44 min-1, p = 0.41). No change in acceleration or mVO2max was seen after submaximal exercise (p > 0.05). The 56.7% reduction in mVO2max supports the hypothesis that in young, healthy individuals a minute of maximal exercise transiently impairs mVO2max which then recovers within six minutes. The NIRS method shows promise in tracking time course changes in mVO2max and warrants further investigation of the transient effects of exercise on mVO2max.

The effects of four hours of normobaric hypoxia on the vestibular control of balance.

Whole-body vestibular-evoked balance responses decrease following ~ 55min of normobaric hypoxia. It is unclear how longer durations of hypoxia affect the vestibular control of balance at the muscle and whole-body levels. This study examined how four hours of normobaric hypoxia influenced the vestibular control of balance. Fifteen participants (4 females; 11 males) stood on a force plate with vision occluded and head rotated rightward while subjected to three blocks of binaural, bipolar stochastic electrical vestibular stimulation (EVS; 0-25Hz, root mean square amplitude = 1.1mA) consisting of two, 90-s trials. The relationship between EVS and anteroposterior (AP) forces or medial gastrocnemius (MG) electromyography (EMG) was estimated in the time and frequency domains at baseline (BL; 0.21 fraction of inspired oxygen-FIO2) and following two (H2) and four (H4) hours of normobaric hypoxia (0.11 FIO2). The EVS-MG EMG short-latency peak and peak-to-peak amplitudes were smaller than BL at H2 and H4, but the medium-latency peak amplitude was only lower at H4. The EVS-AP force medium-latency peak amplitude was lower than BL at H4, but the short-latency peak and peak-to-amplitudes were unchanged. The EVS-MG EMG coherence and gain were reduced compared to BL at H2 and H4 across multiple frequencies ≥ 7Hz, whereas EVS-AP force coherence was blunted at H4 (≤ 4Hz), but gain was unaffected. Overall, the central nervous system's response to vestibular-driven signals during quiet standing wasdecreased forup to four hours of normobaric hypoxia, and vestibular-evoked responses recorded within postural muscles may be more sensitive than the whole-body response.

Ballet practice improves neuromuscular and biomechanical responses to an unexpected standing-slip in older adults.

Falls and fall-induced injuries are common and consequential in older adults. Ballet emphasizes full-body coordination, leg strength, and postural control. However, it remains unknown whether ballet can indeed reduce falls in older adults. This study examined biomechanical and neuromuscular responses of older recreational ballet dancers to an unexpected standing-slip. Twenty older ballet dancers (17 females, 3 males) and 23 age- and sex-matched nondancers (19 females, 4 males) were exposed to an unexpected slip during treadmill standing. The slip-faller rate was the primary outcome. The secondary outcomes were kinematic measurements, including dynamic gait stability, slip distance, and recovery stepping performance (step latency, duration, length, and speed). The tertiary outcome was the electromyography latency of leg muscles (bilateral tibialis anterior, medial gastrocnemius, rectus femoris, and biceps femoris). Fewer dancers fell than nondancers after the standing-slip (45% vs. 83%, P = 0.005, d = 0.970). Dancers displayed better stability at recovery foot liftoff (P = 0.006) and touchdown (P = 0.012), a shorter step latency (P = 0.020), shorter step duration (P = 0.011), faster step speed (P = 0.032), and shorter slip distance (P = 0.015) than nondancers. They also exhibited shorter latencies than nondancers for the standing leg rectus femoris (P = 0.028) and tibialis anterior (P = 0.002), and the stepping leg biceps femoris (P = 0.031), tibialis anterior (P = 0.017), and medial gastrocnemius (P = 0.030). The results suggest that older ballet dancers experience a lower fall risk and are more stable than nondancers following an unexpected standing-slip. The greater stability among dancers could be attributed to more biomechanically effective recovery stepping, possibly associated with the ballet-induced neuromuscular benefit-an earlier leg muscle activation.NEW & NOTEWORTHY This is the first study to examine how older ballet dancers respond to an unexpected external slip perturbation while standing. The results suggest that older ballet dancers experience a reduced fall risk after the slip than their nondancer counterparts. The lower fall risk can be accounted for by dancers' quicker neuromuscular reactions to the slip that result in a more effective recovery step and thus higher stability against backward falls due to the slip.

Adaptive Adjustments in Lower Limb Muscle Coordination during Single-Leg Landing Tasks in Latin Dancers.

Previous research has primarily focused on evaluating the activity of individual muscles in dancers, often neglecting their synergistic interactions. Investigating the differences in lower limb muscle synergy during landing between dancers and healthy controls will contribute to a comprehensive understanding of their neuromuscular control patterns. This study enrolled 22 Latin dancers and 22 healthy participants, who performed a task involving landing from a 30 cm high platform. The data were collected using Vicon systems, force plates, and electromyography (EMG). The processed EMG data were subjected to non-negative matrix factorization (NNMF) for decomposition, followed by classification using K-means clustering algorithm and Pearson correlation coefficients. Three synergies were extracted for both Latin dancers and healthy participants. Synergy 1 showed increased contributions from the tibialis anterior (p < 0.001) and medial gastrocnemius (p = 0.024) in Latin dancers compared to healthy participants. Synergy 3 highlighted significantly greater contributions from the vastus lateralis in healthy participants compared to Latin dancers (p = 0.039). This study demonstrates that Latin dancers exhibit muscle synergies similar to those observed in healthy controls, revealing specific adjustments in the tibialis anterior and medial gastrocnemius muscles among dancers. This research illustrates how dancers optimize control strategies during landing tasks, offering a novel perspective for comprehensively understanding dancers' neuromuscular control patterns.

Contralateral cutaneous reflex modulation during gait in individuals with and without chronic ankle instability

IntroductionChronic ankle instability (CAI), a common seqeula to ankle injury is characterized by a variety of sensorimotor deficits extending beyond the previously injured limb. Cutaneous reflexes have been identified as a potential contributor to these functional limitations with recent studies identifying alterations in reflex patterns following sural nerve stimulation among those with CAI. To date, no studies have measured cutaneous reflexes of the unaffected limb in this population, therefore, the objective of this study was to measure contralateral cutaneous reflexes during gait in individuals with unilateral CAI and healthy controls. MethodsMuscle activity of 6 lower limb muscles was measured in nineteen participants while receiving random, non-noxious sural nerve stimulations during a walking task. ResultsControl reflex patterns were generally well-aligned with previous literature while CAI patterns varied from controls in several muscles throughout the gait cycle. Namely, a lack of lateral gastrocnemius facilitation during late stance and medial gastrocnemius inhibition at midstance. Additionally, a lack of significant BF facilitation throughout contralateral swing was noted. These results indicate reflex alterations extend beyond the affected limb in those with unilateral CAI indicating changes at the spinal level following lateral ankle sprains (LAS). Considering the symptom variability in CAI, the lack of significant reflexes exhibited by the CAI group may be due to increased variability in motor output between subjects or between stimulation trials. ConclusionsThese findings highlight the importance of identifying reflex alterations arising from LAS and subsequently treating these limitations through rehabilitation targeting systemic neural pathways rather than local deficits.

Concurrent plate fixation and pedicled flap coverage for open fractures complicated by soft tissue loss of the tibia in pediatric cohort: a clinical series.

The optimal treatment of open fractures complicated by soft tissue loss of pediatric tibial fractures remains inconclusive. The author described a protocol of concurrent plate fixation and pedicled flap coverage and retrospectively reviewed the outcomes of such injuries. A total of 25 pediatric cases with Gustilo lllB open tibial fracture were treated by single-stage plate fixation and pedicled flap reconstruction. The reviewed information consisted of time to fix and flap, type of plate, type of pedicled flap, fracture union time, postoperative complication and the clinical outcomes by objective scoring system. Fix and flap was undergone between 7 and 12days after injury with the average time of 8.2days. Regarding the type of plate, narrow LCP was applied in 8, 3.5mm precontoured LCP in 10, 5.0mm precontoured in 2 and double LCP in 5. According to soft tissue reconstruction, the medial gastrocnemius flap was selected in 6 cases, myocutaneous medial gastrocnemius flap in 2, soleus flap in 3, hemisoleus flap in 5, reverse sural flap in 6 and combined medial gastrocnemius and hemisoleus flaps in 3. No flap-related complication was demonstrated. All cases established fracture union in between 12 and 24weeks with an average time to union of 17.7weeks. According to postoperative complications, infected plate occurred in 2 cases and implant irritation in 5. According to Puno functional score, excellent results were presented in 7 cases and good results in 18 cases. Single-stage plate fixation and pedicled flap coverage are a reliable regimen for pediatric open fractures complicated by soft tissue loss of the tibia.

Neuromuscular conditions in post-stroke ankle-foot dysfunction reflected by surface electromyography

BackgroundRating scales and linear indices of surface electromyography (sEMG) cannot quantify all neuromuscular conditions associated with ankle-foot dysfunction in hemiplegic patients. This study aimed to reveal potential neuromuscular conditions of ankle-foot dysfunction in hemiplegic patients by nonlinear network indices of sEMG.MethodsFourteen male patients with hemiplegia and 10 age- and sex-matched healthy male adults were recruited and tested in static standing position. The characteristics of the root mean square (RMS), median frequency (MF), and three nonlinear indices, the clustering coefficient (C), the average shortest path length (L), and the degree centrality (DC), of eight groups of muscles in bilateral calves were observed.ResultsCompared to those of the control group, the RMS of the medial gastrocnemius (MG), flexor digitorum longus (FDL), and extensor digitorum longus (EDL) on the affected side were significantly lower (P < 0.05), and the RMS of the tibial anterior (TA) and EDL on the unaffected side were significantly higher (P < 0.05). The MF of the EDL on the affected side was significantly higher than that on the control side (P < 0.05). The C of the unaffected side was significantly higher than that of the control group, whereas the L was lower (P < 0.05). Compared to those of the control group, the DC of the TA, EDL, and soleus (SOL) on the unaffected sides were higher (P < 0.05), and the DC of the MG on the affected sides was lower (P < 0.05).ConclusionThe change trends and clinical significance of these three network indices, including C, L, and DC, are not in line with those of the traditional linear indices, the RMS and the MF. The C and L may reflect the degree of synchronous activation of muscles during a certain motor task. The DC might be able to quantitatively assess the degree of muscle involvement and reflect the degree of involvement of a single muscle. Linear and nonlinear indices may reveal more neuromuscular conditions in hemiplegic ankle-foot dysfunction from different aspects.Trial registrationChiCTR2100055090.

Alpha and beta/low-gamma frequency bands may have distinct neural origin and function during post-stroke walking.

Plantarflexors provide propulsion during walking and receive input from both corticospinal and corticoreticulospinal tracts, which exhibit some frequency-specificity that allows potential differentiation of each tract's descending drive. Given that stroke may differentially affect each tract and impair the function of plantarflexors during walking; here, we examined this frequency-specificity and its relation to walking-specific measures during post-stroke walking. Fourteen individuals with chronic stroke walked on an instrumented treadmill at self-selected and fast walking speed (SSWS and FWS, respectively) while surface electromyography (sEMG) from soleus (SOL), lateral gastrocnemius (LG), and medial gastrocnemius (MG) and ground reaction forces (GRF) were collected. We calculated the intermuscular coherences (IMC; alpha, beta, and low-gamma bands between SOL-LG, SOL-MG, LG-MG) and propulsive impulse using sEMG and GRF, respectively. We examined the interlimb and intralimb IMC comparisons and their relationships with propulsive impulse and walking speed. Interlimb IMC comparisons revealed that beta LG-MG (SSWS) and low-gamma SOL-LG (FWS) IMCs were degraded on the paretic side. Intralimb IMC comparisons revealed that only alpha IMCs (both speeds) exhibited a statistically significant difference to random coherence. Further, alpha LG-MG IMC was positively correlated with propulsive impulse in the paretic limb (SSWS). Alpha and beta/low-gamma bands may have a differential functional role, which may be related to the frequency-specificity of the underlying descending drives. The persistence of alpha band in plantarflexors and its strong positive relationship with propulsive impulse suggests relative alteration of corticoreticulospinal tract after stroke. These findings imply the presence of frequency-specific descending drives to walking-specific muscles in chronic stroke.