Muscle Function Parameters Research Articles

A Novel 5-Chloro-N-Phenyl-1 H-Indole-2-carboxamide Derivative as a Glycogen Phosphorylase Inhibitor: Evaluating the Long-Term Drug Effects on Muscle Function for the First Time.

Compound 1 was previously identified by our team as a glycogen phosphorylase (GP) inhibitor with glucose-lowering activity and demonstrated to have protective effects against myocardial and cerebral ischemia. However, its impact on muscle function has not been clarified. This study is the first to evaluate the long-term effects of GP inhibitors on muscle function and metabolism. After a 28-day administration of Compound 1, we performed assays to assess muscle function and biochemical parameters in rats. We observed reductions in peak holding force, duration, tetanic contraction force, single-contraction force, and electromyographic signals under 20 s and 10 min contraction stimuli. The metabolic analysis showed no significant effects on muscle glycogen, ATP, lactic acid, and uric acid levels at low doses. In contrast, medium to high doses resulted in increased glycogen, decreased ATP, and reduced lactic acid (only at high doses), without affecting uric acid. These findings suggest that Compound 1 may adversely affect muscle function in rats, potentially due to the glycogen inhibition effects of GP inhibitors. This study provides crucial safety data and insights into the long-term effects of GP inhibitors on rat muscles, which will guide future developments and applications.

Diaphragm Muscle Atrophy Contributes to Low Physical Capacity in COVID-19 Survivors.

Fatigue and dyspnea are the most commonly reported long-term complaints in individuals previously infected with SARS-CoV-2. This study aimed to comprehensively evaluate diaphragm muscle function in post-COVID-19 patients and investigate whether potential diaphragm dysfunction contributes to physical functioning impairment. A total of 46 patients who qualified for pulmonary rehabilitation were examined. Diaphragm muscle function parameters were evaluated using ultrasonography, while the severity of dyspnea, aerobic capacity, and the amount of energy used by the body during physical activity were assessed using the six-minute walk test, mMRC scale, and Metabolic Equivalent Task (MET), respectively. We identified that 69.5% of patients had diaphragm atrophy and 6.5% had diaphragm paralysis. The percentage of atrophy was not related to age, gender, BMI, oxygen therapy usage during the COVID-19 infection course, and disease severity. Patients who experienced cough, fever, and no loss of smell during the COVID-19 course had significantly greater diaphragm inspiratory thickness values, while patients with cough and no smell disorders had a significantly lower percentage of diaphragm atrophy. Diaphragm functional parameters were strongly associated with selected variables of exercise tolerance, such as distance in the six-minute walk test, oxygen saturation levels, fatigue, and exertion on the Borg scale. In conclusion, diaphragm muscle dysfunction is a serious long-term post-COVID-19 consequence and can be viewed as a major contributing factor to prolonged functional impairments.

Detecting sarcopenia in obesity: emerging new approaches.

Sarcopenic obesity is a likely common, but certainly underestimated obesity phenotype, with an important negative clinical impact. Its definition and diagnosis have however remained elusive until recently. Substantial progress has been recently made in sarcopenic obesity diagnostic tools, with the first international consensus proposed by the European Society for Clinical Nutrition and Metabolism (ESPEN) and the European Association for the Study of Obesity (EASO). Very encouraging results emerge from initial implementation of the ESPEN-EASO algorithm. In addition, even more recent progress in global consensus on sarcopenia conceptual definition is likely to further enhance consistency in sarcopenic obesity identification. The latter Global Leadership Initiative on Sarcopenia (GLIS) initiative also adopted a new definition of muscle specific strength. Its inclusion in sarcopenia diagnostic constructs opens the possibility of its potential evaluation in sarcopenic obesity, also considering the emerging positive impact of obesity treatment and fat loss on muscle functional parameters. New consensus tools for sarcopenic obesity diagnosis are likely to improve awareness, understanding, identification and treatment of this under-recognized obesity phenotype.

Impact of increased protein intake in older adults: a 12-week double-blind randomised controlled trial.

Emerging evidence suggests health-promoting properties of increased protein intake. There is increased interest in plant protein but a dearth of information in relation to its impact on muscle function. The objective of the present work was to examine the impact of intake of different types of proteins on muscle functional parameters including handgrip strength, biomarkers of metabolic health, sleep quality and quality of life in a group of older adults. Healthy men and women aged 50years and older entered a double-blinded, randomised, controlled nutritional intervention study with three parallel arms: high plant protein, high dairy protein and low protein. Participants consumed once daily a ready-to-mix shake (containing 20g of protein in high protein groups) for 12weeks. Changes in handgrip and leg strength, body composition, metabolic health, quality of life and sleep quality were analysed by linear mixed models in an intention-to-treat approach. Eligible participants (n= 171) were randomly assigned to the groups (plant: n= 60, dairy: n= 56, low protein: n= 55) and 141 completed the study. Handgrip strength increased after the intervention (Ptime= 0.038), with no significant difference between the groups. There was no significant difference between groups for any other health outcomes. In a population of older adults, increasing protein intake by 20g daily for 12weeks (whether plant-based or dairy-based) did not result in significant differences in muscle function, body composition, metabolic health, sleep quality or quality of life, compared with the low protein group.

An obesogenic diet alters muscle function in mdx mice

Duchenne muscular dystrophy (DMD) is a progressive muscle degenerative disease that occurs in 1 in 5000 boys born worldwide. DMD is caused by the absence of a functional dystrophin protein, a major structural protein within muscle. Boys with DMD commonly develop obesity and insulin resistance (IR) compounded by limited mobility and extended treatment with glucocorticoids; however, the extent to which obesity and/or IR affect dystrophic pathology are unknown. We hypothesized that a high fat/high sucrose diet (HF/HSD) would further antagonize disease-related losses in muscle function and that these losses would be partially offset by prednisolone (Pred). To test this hypothesis, male C57 and mdx mice were fed a control diet (CD) or HF/HSD for 19 weeks, with or without Pred supplementation, followed by in vitro muscle function tests. Insulin resistance was confirmed via glucose and insulin tolerance tests. The absolute and relative weight of gastrocnemius, soleus, extensor digitorum longus (EDL), and tibialis anterior muscles were increased in mdx groups compared to C57 (p<0.01) but decreased in mdx groups treated with Pred compared to untreated mdx groups (p<0.01). Muscle mass was similar between dietary treatment groups in C57 and mdx mice. Specific tension in the diaphragm was decreased by disease (p<0.01) but was not altered by diet or Pred treatment. Diaphragms from mdx mice were less fatigue resistant than from C57 mice (p<0.01). Within mdx diaphragms, the addition of Pred and/or HF/HSD decreased fatigue resistance compared to mice maintained on CD. The C57 CD/Pred group was less fatigable than other C57 groups (p<0.01). In the soleus, tetanic force was increased in mdx compared to C57 mice (p<0.01) but was decreased by the HF/HSD in mdx groups (p=0.05). Soleus specific tension was similar between C57 and mdx groups but was decreased in mdx HF/HSD groups compared to CD (p<0.01). In the soleus, mdx groups were less resistant to fatigue than C57 groups (p<0.01); however, the HF/HSD and/or Pred treatment did not further promote fatigue in C57 or mdx mice. In EDL, tetanic force was increased in mdx groups compared to C57 groups (p<0.01), and in both C57 and mdx mice, Pred-treated groups had decreased force compared to untreated groups (p<0.01), but force was not impacted by diet. Specific tension was decreased in mdx groups compared to C57 (p<0.01). Within mdx groups, specific tension of Pred-treated groups was increased compared to untreated groups (p<0.01). The EDL was more resistant to contraction-induced injury in C57 compared to mdx mice. Within mdx mice, the HF/HSD and Pred-treated groups were more resistant to eccentric injury than mdx CD/no Pred mice (p<0.01). These data suggest that a HF/HSD and/or Pred can alter parameters of muscle function. This work is supported by Muscular Dystrophy Association grant #962344. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Efficacy of Core Muscle Exercise Combined with Interferential Therapy in Alleviating Chronic Low Back Pain in High-Performance Fighter Pilots: A Randomized Controlled Trial

BackgroundChronic low back pain (LBP) related to flight is a prevalent health issue in military aviation, impacting pilots. The objective of this investigation was to ascertain if the application of core muscle training in conjunction with interferential current (IFC) therapy results in a reduction in pain severity and associated disability, consequently enhancing core muscle functionality in Chinese Air Force high-performance fighter pilots experiencing chronic LBP.MethodsFifty-three fighter pilots with chronic LBP were randomized into 3 groups: a core muscle exercise combined with IFC group (CG, n = 19), a core muscle exercise group (EG, n = 19), and an IFC group (IG, n = 15). The three groups underwent therapeutic intervention 5 times a week for 12 weeks. The primary outcomes were pain intensity, Oswestry Disability Index (ODI) score and SF-12 health-related quality of life (PCS and MCS) score. Secondary outcomes included evaluations of trunk muscle strength, endurance, and range of motion (ROM) during medial/lateral rotation to assess muscle functionality. Measurements were obtained both before and after the implementation of the intervention therapy.ResultsAfter 12 weeks of intervention therapy, all the health condition parameters significantly improved among the three groups. However, the CG had a significant improvement in pain intensity compared to the EG (MD = − 0.84 scores; 95% CI = − 1.54 to − 0.15; p = 0.013) and the IG (MD = − 1.22 scores; 95% CI = − 1.96 to − 0.48; p = 0.000). Additionally, the CG led to greater conservation of ODI and improved SF-12 PCS scores than did the IG (p < 0.05). Finally, compared with those at baseline, the core muscle function parameters in the CG and EG improved significantly at the end of the study, but no statistically significant differences were observed between the two groups (p > 0.05).ConclusionAmong participants with chronic LBP, three intervention therapies appear effective in reducing pain, diminishing disability, and enhancing quality of life. Also, combined therapy significantly improved pain and disability compared to the other two monotherapies; moreover, combined therapy and core muscle exercise provided similar benefits in terms of core muscle function after 12 weeks of intervention therapy.

Dynamic Muscle Function Parameters in Indian Children and Adolescents with Type 1 Diabetes Mellitus: A Case-Control Study.

Recent evidence reveals that type 1 diabetes mellitus (T1DM) impairs muscle function (MF) in adolescents. However, despite its importance in physical well-being, data on dynamic MF in Indian children and adolescents (C and Y) with T1DM are scarce. We assessed MF using Jumping Mechanography (JM, a measurement method for motion analysis and assessment of muscle power and force). (1) To assess dynamic MF by JM in C and Y with T1DM as compared to healthy controls (2) To determine predictors of MF in children with T1DM. A cross-sectional observational study on 266 children (133 - T1DM duration >1 year with no known comorbidities + 133 age and gender-matched healthy controls) aged 6-19 years. Anthropometry, body composition, and MF (maximum relative power Pmax/mass, maximum relative force Fmax/BW by JM) were recorded. The lean mass index (LMI) was calculated as lean mass (kg)/height (m2). HbA1c was assessed in T1DM. Independent sample t-test and linear regression were performed. MF parameters (Pmax/mass 33.5 ± 7.2 vs 38.0 ± 8.6 W/kg and Fmax/BW 10.5 ± 2.9 vs 11.4 ± 4.1 N/kg, P < 0.05) were significantly lower in T1DM group vs controls. Positive association of body mass index and LMI with both MF parameters and negative association of insulin requirement and HbA1c with Fmax was observed in T1DM. Predictors of MF identified were MMI (Pmax/mass:b = 1.6,95%CI = 0.6-2.6; Fmax/BW:b =2.0,95%CI = 1.6-2.4) and HbA1c (Pmax/mass:b = -2.1,95%CI = -4.5--0.5; Fmax/BW:b = -1.1,95%CI = -2.0--0.2) (P < 0.05). C and Y with T1DM exhibits compromised muscle function. Poor glycaemic control increases the risk of having decreased MF, irrespective of diabetes duration and may contribute to sarcopenia in adulthood.

Deep learning and predictive modelling for generating normalised muscle function parameters from signal images of mandibular electromyography.

Challenges arise in accessing archived signal outputs due to proprietary software limitations. There is a notable lack of exploration in open-source mandibular EMG signal conversion for continuous access and analysis, hindering tasks such as pattern recognition and predictive modelling for temporomandibular joint complex function. To Develop a workflow to extract normalised signal parameters from images of mandibular muscle EMG and identify optimal clustering methods for quantifying signal intensity and activity durations. A workflow utilising OpenCV, variational encoders and Neurokit2 generated and augmented 866 unique EMG signals from jaw movement exercises. k-means, GMM and DBSCAN were employed for normalisation and cluster-centric signal processing. The workflow was validated with data collected from 66 participants, measuring temporalis, masseter and digastric muscles. DBSCAN (0.35 to 0.54) and GMM (0.09 to 0.24) exhibited lower silhouette scores for mouth opening, anterior protrusion and lateral excursions, while K-means performed best (0.10 to 0.11) for temporalis and masseter muscles during chewing activities. The current study successfully developed a deep learning workflow capable of extracting normalised signal data from EMG images and generating quantifiable parameters for muscle activity duration and general functional intensity.

EFFECT OF CHANGES IN THE LENGTH OF THE COMPONENTS OF THE MUSCULOTENDINOUS ELEMENT OF THE ELBOW FLEXOR MUSCLES ON THE ISOMETRIC FORCE AND JOINT TORQUE

Immobilization of the joint leads to the formation of immobilization contracture, which is accompanied by a decrease in the elasticity of tendons and muscles, i.e. loss of full contraction and stretching. The torque in human joints is one of the key indicators in assessing rehabilitation. Objective. To study the effect of changes in the strength, length of muscles and tendons of the elbow joint on the torque in flexion. Methods. The basic OpenSim model arm26 was used for modeling. To determine the change in the length of the components of the muscle-tendon element (MTE), their length was determined at a 90° angle of elbow flexion. The decrease in muscle strength was considered a loss per day for elbow flexors — 1.2 %, extensors — 1.1 %. The decrease in strength was calculated for a period of immobilization of 45 days. Three models were created: Normal — a model without changes in muscle parameters; Contracture — a change in the length of muscles and tendons; Contracture + muscle (CM) — an additional decrease in muscle strength. Results. The obtained data of torques when changing the length of the MTE components showed their increase in conditions of unchanged isometric muscle strength. But this option is not possible after immobilization of the limb. Therefore, it is closer to the real model of СM, in which the torque is significantly reduced by the amount of decrease in muscle strength. These models show a tendency that the change in the components of the MTE due to immobilization increases the joint torque and, when trying to apply excessive force during joint development, can lead to traumatic consequences. During immobilization, the flexor muscles shorten, which prevents the patient from fully extending the elbow joint. Conclusions. This work on predicting the elbow joint torque generated by the muscles can be useful in studying specific clinical situations with elbow joint contractures, but cannot be fully transferred to practice due to the significant conventionality of the model parameters. However, the modeling method can show trends in changes in muscle function parameters when their geometry changes.

Omega-3 polyunsatured fatty acids and physical performance across the lifespan: a narrative review.

Physical performance is a major contributor of mobility and independence during older life. Despite a progressive decline in musculoskeletal function starts from middle age, several factors acting during the life-course can negatively influence musculoskeletal functional capacities. Lifestyle interventions incorporating nutrition and physical exercise can help maximizing the muscle functional capacities in early life as well as preserving them later in life. Among various dietary compounds, omega-3 polyunsaturated fatty acids (PUFAs) are gaining growing attention for their potential effects on muscle membrane composition and muscle function. Indeed, several pathways are enhanced, such as an attenuation of pro-inflammatory oxidative stress, mitochondrial function, activation of the mammalian target of rapamycin (mTOR) signaling and reduction of insulin resistance. We performed a narrative review to explore the existing literature on the relationship between omega-3 PUFAs and physical performance across the life-course. Growing evidence from randomized controlled trials (RCTs) suggests beneficial effects of omega-3 PUFAs on muscle function, including physical performance parameters in mid to later life. On the other hand, despite a direct association in early life is not available in literature, some mechanisms by which omega-3 PUFAs may contribute to improved adult physical performance could be hypothesized. Omega-3 PUFAs are gaining growing attention for their positive effect on muscle function parameters. The integration of physical function measures in future studies would be of great interest to explore whether omega-3 PUFAs could contribute to improved muscle function, starting from early life and extending throughout the lifespan. However, larger and high-quality RCTs are needed to fully elucidate the beneficial effects of omega-3 PUFAs supplementation on muscle mass and function.

Exploring the mechanisms responsible for afterload mismatch in severe aortic stenosis

Abstract Introduction Afterload mismatch (AM) is defined as a reduced ejection fraction (EF) in the setting of severe aortic stenosis (AS) (aortic valve area (AVA) of &amp;lt; 1cm2), but with transaortic pressure gradients in the severe range. The pathomechanism underlying the impaired EF remains unclear, especially with regards to the impact of ventricular hypertrophy and fibrosis, the role of afterload, and the integrity of the intrinsic contractile myocardial strength in AM. This knowledge gap unmasks a lack of understanding into the natural disease progression in AS. Purpose To characterise the morphological and functional contractile mechanics that distinguishes patients with reduced EF from patients with preserved EF in the setting of AS with high transvalvular gradients. Methods A prospective comparative analysis was performed on 21 sequential cases of patients with severe AS, 9 with AM (AVA &amp;lt; 1.0cm2; MG &amp;gt; 40mmHg; EF &amp;lt; 50%) and 12 with normal flow high gradient (NFHG) AS (AVA &amp;lt; 1.0cm2; MG &amp;gt; 40mmHg; EF &amp;gt; 50%). Patients with concomitant valve lesions or previously diagnosed myocardial infarction, were excluded. Myocardial morphology, function and tissue characteristics were evaluated using a) transthoracic echocardiography, b) cardiac magnetic resonance imaging, and c) an invasive hemodynamic study with pressure-volume loop derived data. Results Intrinsic load independent contractile muscle function parameters were similar between AM and NFHG AS (p-value non-significant for cardiac index, dP/dT(max), preload recruitable stroke work slope, end systolic pressure volume relationship slope and Starling contractile index slope). Afterload indices as assessed by peak systolic wall stress and valvuloarterial impedance were significantly higher in AM cases compared to NFHG AS (32.5 vs 19.9 N/cm2; p &amp;lt; 0.01 and 4.8 vs 3.4mmHg/ml; P = 0.05). This was driven by disproportionally higher degrees of valvular stenosis in the AM group (valve area 0.46 vs 0.78cm2; p &amp;lt; 0.01). The AM group expressed a more advanced disease phenotype with more symptoms (NYHA 3.3 vs 2.3; p=0.02), more pulmonary hypertension (50 vs 30mmHg; p=0.04), and more extensive myocardial fibrosis (24% vs 13% of left ventricular mass; p=0.03) (see Figure 1). Neither more severe LVH nor higher degrees of fibrosis in the AM group, was associated with a demonstrable impairment in the intrinsic contractile muscle function. Conclusion Our data suggest that the central problem in AM is related to an excessively increased afterload, primarily driven by more severe valvular stenosis, with preserved intrinsic left ventricular contractile function. AM is characterised by more severe myocardial fibrosis, as a marker of a more advanced disease phenotype, but this did not translate into worse intrinsic contractile muscle function. The known time dependence of progressive valvular stenosis and myocardial fibrosis would suggest that AM is an intermediate phase between NFHG AS and so-called low flow low gradient severe AS.A more advanced phenotype

Effect of Exercises Using Park Fitness Equipment on lower Limb Muscle Function of Inactive Women

Background and Aims This study aimed to investigate the effect of exercises using fitness equipment in parks on the lower limb muscle function of inactive women in Iran. Methods This is a prospective quasi-experimental study. The study population includes all inactive women in Tehran, Iran, aged 25-35 years. Of these, 40 women with no history of physical activity in the past year were selected using a convenience sampling method and randomly divided into two groups of control (n=20) and exercise (n=20). The training program consisted of workouts using fitness equipment in parks (sky walker, aero rider, and leg press machine) at 8 sessions, two sessions per week. The tests included Sargent jump test, triple jump test, star excursion balance test, and 6-meter single-leg timed hop test. The data were analyzed using descriptive statistics (mean and standard deviation), the Kolmogorov-Smirnov test (to examine the normal distribution of data), and the analysis of covariance (to examine differences in variables between the two groups) in SPSS software, version 24. Results After controlling the effect of pre-test scores, there was a significant difference between the two groups in the post-test score of the parameters of muscle function, indicating that exercises using the fitness equipment in parks can affect the lower limb muscle function of inactive women. Conclusion Exercises using park fitness equipment can be used to improve the lower limb muscle function of inactive women.

Identifying the pathophysiological traits of obstructive sleep apnea during dexmedetomidine sedation.

Dexmedetomidine (DEX) has been described as a safe sedative in clinical practice, but its effects on the pathophysiological traits of obstructive sleep apnea (OSA) are unclear. We estimated the effects of DEX sedation on the four key pathophysiological traits of OSA (pharyngeal collapsibility, dilator muscle function, arousal threshold, and loop gain) in adult patients with OSA by conducting a secondary analysis of a prospective diagnostic trial. Pathophysiological traits estimated from polysomnography and the respiratory parameters under natural sleep and DEX-induced sleep were compared. Bivariate and multivariate linear regression analyses were used to estimate the relationship between pathophysiological traits and OSA severity for both sleep states. Adult patients with OSA had a significantly higher pharyngeal collapsibility (Vpassive: 44.9 [15.7 to 53.8] vs. 53.3 [34.2 to 66.3] %eupnea, p < 0.001), arousal threshold (178.5 [132.5 to 234.6] vs. 140.5 [123.2 to 192.3] %eupnea, p < 0.001), and loop gain (LG1: 0.74 ± 0.25 vs. 0.60 ± 0.17, p < 0.001; LGn: 0.52 ± 0.12 vs. 0.44 ± 0.08, p < 0.001) during DEX-induced sleep compared with natural sleep. There was no significant difference in dilator muscle function or PSG respiratory parameters between natural versus DEX-induced sleep states. Bivariate regression analysis showed varying degrees of correlation between OSA traits and severity. Multiple regression analysis indicated that collapsibility was the strongest predictor of the apnea-hypopnea index for both sleep states. Dexmedetomidine sedation in patients with OSA increased the pharyngeal collapsibility without impairing dilator muscle function, while elevating arousal threshold and increasing loop gain.

Can Leucine Supplementation Improve Frailty Index Scores?

Sarcopenia and frailty are important conditions that become increasingly prevalent with age. There is partial overlap between the two conditions, especially in terms of the physical aspects of the frailty phenotype: low grip strength, gait speed, and muscle mass. This study examined whether administration of the essential branched-chain amino acid leucine, besides improving sarcopenia, may reduce frailty assessed by frailty index (FI) in older institutionalized people living in nursing homes. We conducted a secondary analysis of a placebo-controlled, randomized, double-blind design study (ClinicalTrials.gov NCT03831399). The study included fifty males and females aged 65 and over who were living in nursing homes and did not have dementia. The participants were randomized to a parallel group intervention of 13 weeks' duration, with a daily intake of leucine (6 g/day) or placebo (lactose, 6 g/day). The outcome of this study was to evaluate whether there was a change in the level of a 95 item FI compared to the baseline and to compare the effect of the leucine group versus the placebo group. A significant inverse correlation was found between FI and performance of the activities of daily life, cognitive function, gait and balance, muscle function parameters, and nutritional status (p < 0.001 in all cases). There were no statistically significant differences in FI levels at baseline (placebo group FI 0.27 ± 0.08 and leucine group FI 0.27 ± 0.10) and at the 13 week follow-up (placebo group FI 0.28 ± 0.10 and leucine group FI 0.28 ± 0.09). There were also no significant differences between the leucine and placebo groups in the mean FI difference between baseline and follow-up (p = 0.316, Cohen's d: 0.04). This pilot study showed that a nutritional supplementation with leucine did not significantly modify the frailty index in older nursing home residents.

The effects of inspiratory muscle training on swimming performance: A study on the cohort of swimming specialization students

PurposeCurrent evidence posits a strong correlation between respiratory muscle function and swimming performance. Despite this, few studies have explored the integration of inspiratory muscle training (IMT) into standard swimming training regimens, which remains an unexplored avenue for improving performance in swimmers. This study aims to evaluate the potential advantages of IMT for enhancing respiratory function and swimming performance and determine whether such training could induce beneficial physiological adaptations. MethodsWe designed and conducted a randomized controlled trial involving 43 swimming specialization students aged 18–25 years. Participants were randomly allocated to two groups: a control group, which followed regular swimming training, and an experimental group, which complemented the standard training with IMT. The intervention lasted for six weeks. Key outcomes measured included swimming performance metrics (time of 50 m freestyle, number of breaths in 50 m freestyle, distance before first breath in freestyle, time of 100 m freestyle) and various inspiratory muscle function parameters such as vital capacity (VC), maximum inspiratory pressure (MIP), maximum inspiratory flow (MIF), and maximum inspiratory capacity (MIC). We also assessed certain biochemical parameters, including hemoglobin, creatine kinase (CK), blood urea nitrogen (BUN), testosterone, and cortisol concentrations. ResultsFollowing the training period, the experimental group exhibited significant improvements in swimming performance and respiratory function parameters. We also noted an increase in hemoglobin levels and a reduction in testosterone concentrations in this group, suggesting beneficial physiological adaptations in response to the combined IMT and swimming training. ConclusionOur findings underline the potential of IMT as a supplementary training modality for enhancing respiratory function and improving swimming performance. The changes in biochemical parameters suggest physiological adaptations that might contribute to these observed improvements. This study opens the door for future research on the benefits of integrating IMT into training regimens for competitive swimmers. Further investigation is warranted to fully elucidate the mechanisms behind the observed benefits and to validate these findings in a larger cohort and other athlete populations.

Applicability of the seated step test for assessing thigh muscle sarcopenia in older individuals

Assessment of lower limb muscle mass and related functions in older individuals is important because of their essential role in maintaining locomotion and activities of daily living. Therefore, a simple and reliable method for assessing these parameters should be established. The seated step test is easy and safe and can be used to assess lower limb agility; however, its relationship to skeletal muscle mass and function remains unknown. The present study aimed to investigate the relationships between the seated step test and lower limb muscle mass and function. For the analysis, we included 85 participants aged 73.1 ± 6.0 years. The participants performed an alternate up-down leg step test for 10 s while seated in a chair. Lower limb muscle mass was measured using bioimpedance analysis. Skeletal muscle mass index (SMI) was calculated using the following equation: lower limb muscle mass (kg) / height2 (m2). As the muscle functional parameters, we measured the isometric knee extension peak torque (KEPT), knee flexion peak torque (KFPT), and rate of torque development (RTD) for isometric knee extension in all participants. The seated step test score had a significant relationship with KEPT, KFPT, and SMI, but not with RTD. In the single regression analysis, the seated step test significantly predicted KEPT, KFPT, and SMI. These results suggest that up-down seated step test can be a reliable method to estimate lower limb muscle size and function in older individuals.

Nonsurgical hypoparathyroidism is associated with skeletal muscle dysfunction and restrictive lung disease.

Systematic assessment of skeletal muscle function is lacking in patients with nonsurgical hypoparathyroidism (HP). Whether muscle dysfunction involves respiratory muscles and results in restrictive lung disease (RLD) is not studied. To assess skeletal muscle and pulmonary functions in patients with HP. Observational case-control study. Thirty patients with HP (mean age 37.7 years, 60% males) and age, sex, and body mass index-matched forty healthy-controls were assessed for skeletal muscle function by hand-grip strength, short physical performance battery (SPPB) test, dual-energy x-ray absorptiometry, and electromyography. Pulmonary function was assessed by spirometry, body plethysmography, diffusion lung capacity for carbon monoxide and diaphragmatic ultrasound. Patients with HP had lower serum calcium (2.25±0.15 vs 2.4±0.12 mmol/L, p<0.001), serum magnesium [median (interquartile-range) 0.74 (0.69-0.82) vs 0.78 (0.69-0.90) mmol/L, p=0.04], hand-grip strength (18.08±8.36 vs 22.90±7.77 kg, p=0.01) and composite SPPB score (9.5 [7-10] vs 12 [12-12], p< 0.001) compared to healthy-controls. Electromyographic evidence of myopathy was seen in 23% (5 of 22) patients with HP, but in none of the controls (p=0.08). The prevalence of RLD was higher in the HP cohort compared to that in controls (24% vs 0%, p=0.01). Diaphragmatic excursion (4.22±1.38 vs 5.18±1.53 cm, p=0.01) and thickness (3.79±1.18 vs 4.28±0.94 mm, p=0.05) on deep inspiration were reduced in patients with HP. Detailed testing of patients with HP without overt muscle and lung diseases revealed significant impairment in parameters of skeletal muscle function. Myopathy and RLD were observed in a considerable proportion of patients with HP.

The role of microRNAs in muscle wasting and recovery during critical illness: a systematic review

AbstractIntroductionCritical illness associated with intensive care unit (ICU) admission often results in persistent skeletal muscle wasting and may lead to frailty in older and patients with multi‐morbidity. Early recognition of patients at high‐risk of long‐term complications could provide opportunities to minimize the impact of critical illness and improve health and quality of life. MicroRNAs (miRs) are short, non‐coding RNAs that regulate approximately two‐thirds of the human genome and are involved in most biological processes. Multiple studies have demonstrated their role in muscle development and disease and their potential as biomarkers of muscle wasting.Aim and methodsThis systematic review examined the potential of miRs as biomarkers and therapeutics for muscle wasting during and following critical illness. PubMed and Scopus databases were searched for terms associated with critical illness, ICU, muscle wasting, frailty and microRNAs from inception to June 2022 (PROSPERO number CRD42022339531).ResultsOut of 537 articles, seven studies met the inclusion criteria and examined skeletal muscle and circulating miRs in the context of muscle wasting and/or frailty related to critical illness. Across the seven studies, 27 different miRs were identified that were reported to be dysregulated in the muscle and four in the blood, plasma or serum of critically ill patients. Four miRs were reported to be altered in both muscle and blood during critical illness and their levels moderately correlated with parameters of muscle function. These included canonical muscle‐enriched miRs (myomiRs), such as miR‐133, miR‐1 and miR‐181, which correlated with muscle strength in critically ill patients. However, most of the miRs reported to be dysregulated in the muscle following critical illness were examined in one article only.ConclusionsThis systematic review highlights the potential of miRs as biomarkers of skeletal muscle wasting and ICU‐associated weakness following critical illness, suggesting the need for larger validation studies using unbiased techniques. We have described circulating and muscle microRNAs, which correlated with muscle parameters during critical illness. However, the limited number of studies in this area highlights the requirement for further studies before these could be considered in clinical practice.

Paper 31: Quantitative MRI of the Hamstring Muscles Ten Years After Autograft Hamstring ACLR

Paper 31: Quantitative MRI of the Hamstring Muscles Ten Years After Autograft Hamstring ACLR

The Impact of Whole-Body Vibration Training on Lower-Extremity Muscle Function in Older Adults: A Systematic Review and Meta-Analysis

This review aimed to analyze the impact of whole-body-vibration (WBV) training on strength, power, muscle endurance, functional lower-extremity flexibility (FLEF), and functional lower-extremity strength (FLES) in older adults and to evaluate the effectiveness of different WBV training periods. Electronic searches were conducted using four databases. The methodological quality and level of evidence of the selected articles were assessed by two reviewers. Standardized mean differences (SMD) and 95% confidence intervals (CIs) were calculated. Nineteen studies were included (474 participants; mean age 74.27 years). Strength was measured by isokinetic, isometric, or isotonic contraction using an isokinetic dynamometer or weight-training machines. Power was measured by an assessment task that required maximal force in a short period of time. Endurance was evaluated by maximal repetition of tasks, FLEF by chair stand-and-reach and functional reach tests, and FLES by the sit-to-stand test. Meta-analysis showed that WBV training had significant effects on strength (SMD = .54; CIs = .40, .67), power (SMD = .58; CIs = .28, .89), muscle endurance (SMD = .82; CIs = .36, 1.29), FLEF (SMD = .31; CIs = .06, .55), and FLES (SMD = -.75; CIs = -1.18, -.33). Our findings suggest that 1) WBV training improves overall lower-extremity muscle function in older adults, especially muscle endurance; 2) a minimum of 8 weeks of WBV training is recommended to improve strength, muscular endurance, and power; and 3) a longer period of the WBV training is more effective at improving muscle endurance, power, and strength but not FLEF and FLES. Therefore, WBV training is strongly recommended to improve various muscle function parameters in older adults.