Muscle Strength In Subjects Research Articles

Effect of Partial Blood Flow Restriction Training in Improving Physical Functioning among Middle-Aged Subjects with Knee Osteoarthritis: A Pilot Study

Background: Blood Flow Restriction (BFR) training combines low-intensity exercise with blood flow occlusion toproduce outcomes comparable to those of high-intensity training. BFR is as effective as high-intensity protocolsknown to enhance knee extensor muscle strength in subjects with knee osteoarthritis (OA). Therefore, the aimof this study is to find out the effect of Partial Blood Flow Restriction Training on pain and physical functioningamong knee OA subjects.Purpose: To assess the effectiveness of Partial Blood Flow Restriction Training in Improving Physical FunctioningAmong Middle-Aged Subjects with Knee Osteoarthritis.Materials and Methods: This is the pilot study where twenty subjects with knee OA were divided randomly intotwo equal groups. Group “A” received BFR training combined with conventional exercise two times/week andGroup “B” received conventional exercise two times/week. Numeric Pain Rating Scale (NPRS), Western Ontarioand McMaster Universities Arthritis Index (WOMAC) were used to evaluate subjects at two intervals (Pre-Testand Post-Test).Results: The difference between the Group A and Groups B was statistically significant (p<=0.001). Henceconventional exercise combined with blood flow restriction training shows significant improvement thanconventional exercise among OA knee subjects.Conclusion: This pilot study concluded that the conventional exercise combined with blood flow restrictiontraining was effective in subjects with OA knee.

Characteristics of Skeletal Muscle Strength in Subjects With Interstitial Lung Disease

ObjectivesTo investigate muscle strength and the prevalence of muscle weakness in adults with interstitial lung diseases (ILDs) compared to healthy subjects. DesignCross-sectional (description of clinical features). SettingPublic referral center (University Hospital). ParticipantsOne hundred and twelve adults with ILD (n=48, 60±10yr, 68% female) and healthy counterparts (control group, n=64, 57±10yr, 58% female) (N=112). InterventionNot applicable. Main Outcome Measure(s)Muscle strength and prevalence of muscle weakness in adults with ILD. Muscle strength was assessed via maximal isometric voluntary contraction of dominant upper and lower limb muscle groups. Data from the control group were used to generate reference equations. Muscle weakness was defined as a muscle strength value below the lower limit of normal calculated using data from the control group. Data were expressed as mean ± SD or median [interquartile range] according to the data distribution. ResultsCompared to the control group, adults with ILD had lower muscle strength for all muscle groups assessed (values presented as %predicted: pectoralis major 75[57-86]%; quadriceps 72[58-87]%; latissimus dorsi 76[57-103]%; deltoid 74[64-98]%; biceps brachii 78[64-91]%; triceps brachii 84[62-101]%; P≤.001 for all). Prevalence of muscle weakness in people with ILD was 40% for pectoralis major, 25% for latissimus dorsi, 16% for triceps brachii, 20% for biceps brachii, 27% for deltoid and 46% for quadriceps. ConclusionsAdults with ILD present a generalised reduction in peripheral Muscle strength, ranging between 20% to 46% of people depending on the muscle group assessed. and it was more prevalent in lower limb muscles.

Acute Effects of Whole-Body Vibration on Muscle Strength in Subjects with Shoulder Instability

Acute Effects of Whole-Body Vibration on Muscle Strength in Subjects with Shoulder Instability

A DMP-Based Motion Generation Scheme for Robotic Mirror Therapy

Hemiparesis has become prevalent in recent years, and robot-assisted rehabilitation provides great therapeutic potential. Robotic mirror therapy is a promising approach for hemiplegic patients by transmitting the motion of the healthy limb (HL) to the impaired limb (IL), where the wearable robot assists the IL to mimic the HL's action to stimulate the active participation of the injured muscles. However, complete replication of the HL's movement trajectory without considering the IL's muscle strength is not satisfactory for rehabilitation. In this article, a motion generation scheme is proposed for robotic mirror therapy. The robot's movement trajectory is modeled with dynamic movement primitive (DMP), and the physical human–robot interaction is formulated as an impedance model and coupled with the DMP model. The subject's muscle strength is evaluated with skin surface electromyography signals and transferred to the robot's joint stiffness. In order to adapt the human–robot coupled DMP model parameters to varying subject performance, a reinforcement learning algorithm is designed to optimize the robot's movement trajectory and stiffness profile, where the training safety and rehabilitation improvement are both guaranteed. The proposed method is validated using a lower extremity rehabilitation robot, and experimental results demonstrate its feasibility and superiority.

Screening of malnutrition using Patient-Generated Subjective Global Assessment tool and hand muscle strength in subjects with pancreatitis.

Pancreatitis patients are at an increased risk of malnutrition due to impaired digestion, absorption, and metabolism. The degree of malnutrition is dependent on the duration, viz. acute or chronic. Studies on nutritional status in patients with pancreatitis are limited. Prevalence of nutritional status, physical functioning, and muscle strength among the subjects are scarce globally. The main aim of this study was to screen the status of malnutrition using appropriate screening tools and to assess hand muscle strength among subjects. A cross-sectional study was conducted on 64 subjects (18-80 years old, 59 males and 5 females) in Mysore city, Karnataka. The patients were screened for malnutrition using a standard tool Patient-Generated Subjective Global Assessment (PG-SGA) and handgrip strength on both dominant and nondominant hands. The majority of patients (n = 44) were categorized as moderately malnourished/suspected malnutrition (Stage B) according to PG-SGA.A significant difference (p < 0.005) in handgrip strength was seen inmen aged 31-40 (t = -3.287)and 41-50 (t = -5.487) years compared tohealthy adults. This study was able to identify patients at risk of malnutrition when thePG-SGA tool was used along with handgrip strength and other anthropometric parameters.

Effects of Inspiratory Muscle Training and High-Intensity Interval Training on Lung Function and Respiratory Muscle Function in Asthma.

Asthma is a heterogeneous disease, usually characterized by chronic airway inflammation. Although inspiratory muscle training (IMT) and high-intensity interval training (HIIT) are beneficial for patients with asthma, controversies persist. Therefore, we aimed to investigate the effects of IMT and HIIT on lung function and respiratory muscle function of subjects with asthma. We searched PubMed, Embase, Web of Science, and the Cochrane Library databases up to May 2021. Inclusion criteria were randomized controlled trials (RCTs) of subjects with asthma who received either IMT or HIIT. The outcome measures were changes in lung function and respiratory muscle function. A total of 13 RCTs (10 in IMT and 3 in HIIT) were included, with a total of 598 subjects. The meta-analysis showed a significantly improved FEV1 of the expected value (FEV1%pred) (mean difference [MD] 4.49% [95% CI 2.31-6.67], P < .001; I2 = 13%), FVC of the expected value (FVC % pred) (MD 5.72% [95% CI 3.56-7.88], P < .001; I2 = 0%), FEV1/FVC % (MD 5.01% [95% CI 2.45-7.58], P < .001; I2 = 25%), FVC (L) (MD 0.21 L [95% CI 0.03-0.40], P = .02; I2 = 0%), maximum inspiratory pressure (PImax) (MD 27.62 cm H2O [95% CI 6.50-48.74], P = .01; I2 = 96%), and PImax (%pred) (MD 27.35% [95% CI 6.94-47.76], P = .009; I2 = 83.5%) in the IMT group. There was no statistical significance in maximum expiratory pressure. IMT improved pulmonary function (FEV1%pred, FVC) and inspiratory muscle strength in subjects with stable asthma. Due to the small number of RCT studies included and the limited outcome measures involving HIIT, we were unable to draw conclusions about whether HIIT was beneficial in this meta-analysis. Moreover, clinical heterogeneity exists in different areas such as population and training programs; the above conclusions still need to be confirmed in future studies.

Increasing Protein Ingestion Minimally Increases Lean Mass and Muscle Strength in Subjects Enrolled in Resistance Exercise Training a Systematic Review and Meta-Analysis

ObjectivesThis systematic review, meta-analysis, and meta-regression aimed to determine if increasing daily protein ingestion contributes to gaining lean mass (LM), muscle strength, and physical/functional test performance in healthy persons.MethodsThe present review was registered on PROSPERO - CRD42020159001. A systematic search in Medline, Embase, CINAHL, and Web of Sciences databases was undertaken. Randomized controlled trials (RCT) including healthy and non-obese adult participants increasing daily protein intake were selected. Subgroup analysis, splitting the studies by participation in resistance exercise training (RE), age (< 65 or ≥ 65 y), and daily protein ingestion were also performed.Results74 RCT fit our inclusion criteria. The age range of the participants was 19 to 85 y, and study protocols in the trials lasted from 6 to 108 wks (76% of the studies between 8 and 12 wks). In ∼80% of the studies, baseline protein ingestion was at least 1.2 g of protein/kg/d. Increasing daily protein ingestion may lead to small gains in LM in subjects enrolled in RE (SMD [standardized mean difference] = 0.22, CI95% [95% confidence interval] 0.14:0.30, P < 0.01, 62 studies, moderate level of evidence). Also, ≥ 65 y subjects ingesting 1.2–1.59 g of protein/kg/d and younger subjects (< 65 y) increasing their ingestion to ≥ 1.6 g of protein/kg/d during RE showed a higher LM gain. Lower-body strength gain was slightly higher at ≥ 1.6 g of protein/kg/d during RE (SMD = 0.40, CI95% 0.09:0.35, P < 0.01, 19 studies, low level of evidence). Bench press strength was slightly increased by ingesting more protein in < 65 y subjects during RE (SMD = 0.18, CI95% 0.03:0.33, P = 0.01, 32 studies, low level of evidence). Effects on handgrip strength are unclear and only marginal for performance in physical function tests.ConclusionsThe number of studies increasing daily protein ingestion alone was too low (n = 6) to conduct a meta-analysis. The current evidence shows that increasing protein ingestion by consuming supplements or food, resulted in small additional gain in LM, and lower body muscle strength in healthy adults enrolled in RE. Effects on bench press strength and performance in physical function tests are minimal. The effect on handgrip strength was unclear.Funding SourcesThis research received a grant from the International Life Science Institute (Europe) and CNPq.

Comparison of the effects of low level laser and insoles on pain, functioning, and muscle strength in subjects with stage 2 posterior tibial tendon dysfunction: A randomized study.

Low level laser therapy (LLLT) is known to be effective in tendinopathies. No study yet investigated the effect of LLLT on posterior tibial tendon dysfunction (PTTD) in comparison to orthotic treatment. The aim was to compare the effects of LLLT and insole application on pain, function and muscle strength in subjects with stage 2 PTTD. Fifty-two subjects with stage 2 PTTD were randomly assigned to the LLLT and insole groups. The foot pain, function and strength of invertor and evertor muscles of the subjects was evaluated before and after treatment, and after 9 months. Significant improvement was observed in the foot function and pain (p< 0.05) in both groups after treatment, but in the 9-month follow-up, the insole group had better values. The increase in 180∘.sec-1 concentric invertor muscle strength was found significant after the treatment and in month-9 as compared to the initial values (p< 0.05). Both treatments are effective in reducing treating foot pain, as well as improving the function in subjects with stage 2 PTTD. However, at the end of the 9-month follow-up, it was seen that insoles were more effective. Neither method had a clinically important effect on muscle strength.

Effects of TRX Suspension Training on Proprioception and Muscle Strength in Female Athletes with Functional Ankle Instability

Background: Functional ankle instability (FAI) is a common consequence of ankle sprain injury, especially in high-impact sports. Objectives: To investigate the effect of six weeks of suspension training with total resistance exercises (TRX) on proprioception and muscle strength in female athletes with FAI. Methods: Thirty female athletes with FAI (age: 21.9 ± 2.2 years, height: 169.3 ± 4.2 cm, and weight: 59.8 ± 6.1 kg) were randomly assigned to two equally numbered groups: TRX training and controls based on inclusion and exclusion criteria. In the pre-test, the anthropometric variables and also proprioception accuracy and muscle strength of subjects were evaluated by joint angle reset test (JART) and manual muscle testing (MMT) in both dorsiflexion and plantarflexion motions. The training group completed three sessions per week with progressive load for six weeks, and each training session lasted 15 - 20 minutes, whilst control subjects continued with their normal activity without special sport activities. After six weeks of training, all tests performed in the pre-test phase were also performed in the post-test phase. The t-test was used for statistic analysis (α ≤ 0.05). Results: The findings showed that TRX training significantly improved the proprioception accuracy (P ≤ 0.001) and muscle strength (P ≤ 0.001) in the training group rather than the control group. No statistically significant difference was found in any of the tests between pre-test and post-test for the control group (P &gt; 0.05). Conclusions: Six weeks of TRX suspension training had a positive effect on strength and proprioception accuracy in female athletes with FAI.

Effect of Respiratory Muscle Training on Pitch Range and Sound Duration in Brass Instrument Players and Singers

Effective use of respiratory organs is important for musicians. Therefore, the impact of Respiratory Muscle Training (RMT) on phonation is open to research. The aim of this study was to investigate the measurable effects of RMT on blowing in brass instrumental and on voice performance in singers. Thirty musicians were recruited and separated into a four groups. The brass instrumental and singers groups were further subdivided into control and RMT groups for a 4 week RMT intervention giving a total four groups: singers experimental (SE; n:10), singers control (SC; n:10), brass instrument players experimental (BIPE; n:5), and BIPC (n:5). The groups selected from the musicians of Samsun State Opera and Ballet Directorate and Samsun Metropolitan Municipality Band Team participated in the study. After 4 weeks of RMT application in the study groups, significant increase in all parameters except Forced vital capacity/Forced expiratory volume in 1 second was observed in the values of pulmonary function tests and respiratory muscle strength in subjects with SE and BIPE (P < 0.05). The most significant results of this study are that in addition to changes in the duration of phonation (SE 36%), high-pitch (SE 79%, BIPE 27%) and low-pitch sounds (BIPE 61% and SE 42%), the SE (15%) and BIPE (3%) groups reached higher pitches in the high-pitch notes. It was determined that performance of the highest and lowest pitch sounds within a vocal register in a single breath and phonation times can be improved by RMT.

Treadmill training with partial body weight support in subjects with incomplete spinal cord injury: a systematic review

The partial body weight supported treadmill training is a common therapeutic strategy in rehabilitation of people with spinal cord injuries. To analyze its effects on gait, balance and muscle strength in people with incomplete spinal cord injury compared to conventional treatment or overground gait training. A compilation of clinical trials from 2007 to 2019 was carried out. We included articles that evaluate the effects of body weight supported treadmill training on gait, balance and muscle strength in subjects with incomplete spinal cord injury. A total of six articles were analyzed. The walking cadence, speed and resistance improved in the participants that received the intervention compared to those that were treated with conventional training. The functionality, balance and strength improved in most studies, but there were not differences between them. Body weight supported treadmill training improves the spatiotemporal parameters of walking and resistance in subjects with incomplete spinal cord injury, but in most variables analyzed (balance, functionality and strength) the changes are not superior to those observed after conventional training.

Is Femoral Version Associated with Changes in Hip Muscle Strength in Females with Symptomatic Femoroacetabular Impingement?

Objective The aim of the present study was to evaluate the association between femoral anteversion and hip muscle strength in subjects with femoroacetabular impingement syndrome. Method The femoral version angles described in the arthro-magnetic resonance images and isokinetic tests were retrospectively evaluated from July 2016 to December 2017. The inclusion criteria were: a) femoral version evaluated by the same radiologist; b) α angle ≥ 55°; and c) no limiting pain during the isokinetic test. Flexion/extension, abduction/adduction, and internal/external rotation peak torques were evaluated at 30° per second in 5 repetitions. The correlation between femoral version and muscle strength was evaluated by simple linear regression at a 5% significance level. Results A total of 37 females filled the inclusion criteria, and 51 symptomatic hips were evaluated. There was no correlation of the femoral anteversion in the flexion, extension, abduction, adduction, external rotation and internal rotation peak torques. Conclusion Femoral anteversion did not show a correlation with hip muscle strength in females with symptomatic femoroacetabular impingement.

Effects of Electrical Muscle Stimulation in Subjects Undergoing Prolonged Mechanical Ventilation.

Muscle atrophy and deconditioning are common complications in patients on prolonged mechanical ventilation (PMV). There are few studies that reviewed the effects of electrical muscle stimulation in this population. The purpose of this study was to examine the effects of electrical muscle stimulation on muscle function and hospitalization outcomes in subjects with PMV. Subjects on mechanical ventilation for ≥21 d were randomly assigned to the electrical muscle stimulation group (n = 16) or the control group (n = 17). The electrical muscle stimulation group received daily muscle electrical stimulation for 30 min/session for 10 d. The measurement of muscle strength (by medical research council [MRC] scale), leg circumference, and physical functional status (by Functional Independence Measure [FIM] scores) were performed before and after completion of the study. The length of stay in respiratory care center of subjects were recorded. After electrical muscle stimulation, there was no difference in pulmonary function between the electrical muscle stimulation and control groups. Significantly increased in MRC points was found in the electrical muscle stimulation group after intervention (2 [1-7] points vs 2 [1-3.5] points, respectively, P = .034). No difference in MRC points was found between baseline and post-measurement in the control group (1[1-2] points vs 1[1-2.5] points, respectively, P > .99). At the end of the study, leg circumference in control group significantly decreased when compared with baseline (47.5 ± 8.3 cm vs 44.6 ± 5.7 cm, respectively, P = .004) and remained unchanged in the EMS group. However, no significant differences were found between the electrical muscle stimulation and control groups. There was no difference in physical functional status and hospital stay between the electrical muscle stimulation and control groups. Electrical muscle stimulation enhanced muscle strength in subjects who received PMV. Electrical muscle stimulation can be considered a preventive strategy for muscle weakness in patients who receive PMV. (ClinicalTrials.gov registration NCT02227810.).

Dietary protein intake and upper leg muscle strength in subjects with knee osteoarthritis: data from the osteoarthritis initiative.

The aims of this study were (1) to describe dietary protein intake, and (2) to evaluate the association between dietary protein intake and upper leg muscle strength in subjects with knee osteoarthritis (OA). Baseline data from the OA was used, in a cross-sectional study. All subjects were diagnosed with symptomatic and radiographic knee OA. Daily dietary protein intake was measured with the Block Brief 2000 food frequency questionnaire (g/kg body weight). The sum of knee flexion and extension strength of the index knee (N/kg bodyweight) was assessed with the Good Strength chair test. Linear regression analysis was used to test the association between dietary protein intake and muscle strength, adjusting for relevant confounders. Data from 1316 subjects (mean age 61.4 ± SD 9.1years, 57.0% female) were used. The mean daily protein intake was 0.72 ± SD 0.30g/kg bodyweight, and 65.1% of the subjects had a protein intake lower than the recommended daily allowance of 0.8g/kg bodyweight. The mean muscle strength was 5.4 ± SD 2.1N/kg bodyweight. Lower protein intake was significantly associated with lower muscle strength (B = 0.583, 95% CI 0.230-0.936, p = 0.001). The majority of the subjects with knee OA had a dietary protein intake lower than the recommended daily allowance. Lower protein intake was associated with lower upper leg muscle strength. Longitudinal observational and interventional studies are needed to establish whether dietary protein intake has a causal effect on muscle strength in subjects with knee OA.

Resistance exercise alone improves muscle strength in growth hormone deficient males in the transition phase.

Background During the transition phase (TP), patients with growth hormone deficiency (GHD) exhibit decreased muscle strength. Studies assessing the effects of resistance exercise alone on muscle strength in these individuals are scarce. The objective of this study was to evaluate the effects of a program of resistance exercise (PRE) on parameters of muscle strength in subjects in the TP and with childhood-onset GHD treated with recombinant GH (rGH). Methods Sixteen male patients were enrolled and divided into two groups: GHD (n=9) and GH sufficiency (GHS, n=7). Patients with GHD underwent a 12-week PRE followed by another 12-week PRE plus rGH, while GHS patients underwent a 12-week PRE alone. Dynamic knee muscle strength was evaluated using an isokinetic dynamometer. Results Before PRE, there were significant differences between the groups regarding the results of flexor peak torque (FPT) normalized to body weight (BW-FPT) in the dominant (DO, p=0.008) and non-dominant (ND, p=0.01) limbs, and in the agonist/antagonist (A/A) ratio in the DO (p=0.02) and ND (p=0.006) limbs. After PRE in the GHD group, values of FPT and BW-FPT in both limbs increased significantly (p<0.001) and independently of rGH, while the A/A ratio value improved significantly (p<0.001) in the ND limb. Conclusions A short period of PRE alone was sufficient to improve parameters of muscle strength in young male adults with childhood-onset GHD.

Scapular muscles weakness in subjects with traumatic anterior glenohumeral instability

ObjectiveTo investigate possible alterations on scapular muscle strength in subjects with traumatic anterior glenohumeral instability. DesignCross-sectional study. Setting: Laboratory setting. Participants: Fifty-two subjects of both sexes: 26 healthy and 26 with traumatic anterior glenohumeral instability. Main outcome measuresSubjects performed maximal isometric and concentric isokinetic contractions of shoulder protraction and retraction in scapular and sagittal planes, at slow (12.2 cm/s) and fast (36.6 cm/s) speeds. ResultsSubjects with glenohumeral instability presented lower peak force of protraction and retraction during isometric and fast speed tests in the scapular plane; and of isometric protraction in the sagittal plane. ConclusionsPeople with traumatic anterior glenohumeral instability present muscle weakness of scapular protractors and retractors. Considering the importance of the scapulothoracic muscles for the dynamic stability of the glenohumeral joint, strengthening of these muscles is recommended for rehabilitation of traumatic anterior glenohumeral instability.

EVALUATION OF MUSCLE STRENGTH IN MEDULLAR INJURY: A LITERATURE REVIEW

ABSTRACT Objective: To identify the tools used to evaluate muscle strength in subjects with spinal cord injury in both clinical practice and scientific research. Methods: Initially, the literature review was carried out to identify the tools used in scientific research. The search was conducted in the following databases: Virtual Health Library (VHL), Pedro, and PubMed. Studies published between 1990 and 2016 were considered and selected, depicting an evaluation of muscle strength as an endpoint or for characterization of the sample. Next, a survey was carried out with physiotherapists to identify the instruments used for evaluation in clinical practice, and the degree of satisfaction of professionals with respect to them. Results: 495 studies were found; 93 were included for qualitative evaluation. In the studies, we verified the use of manual muscle test with different graduation systems, isokinetic dynamometer, hand-held dynamometer, and manual dynamometer. In clinical practice, the manual muscle test using the motor score recommended by the American Spinal Cord Injury Association was the most used method, despite the limitations highlighted by the physiotherapists interviewed. Conclusion: In scientific research, there is great variation in the methods and tools used to evaluate muscle strength in individuals with spinal cord injury, differently from clinical practice. The tools available and currently used have important limitations, which were highlighted by the professionals interviewed. No instrument depicts direct relationship of muscle strength and functionality of the subject. There is no consensus as to the best method for assessing muscle strength in spinal cord injury, and new instruments are needed that are specific for use in this population.

Resistance Training Improves Sleep Quality in Subjects With Moderate Parkinson's Disease.

Silva-Batista, C, de Brito, LC, Corcos, DM, Roschel, H, de Mello, MT, Piemonte, MEP, Tricoli, V, and Ugrinowitsch, C. Resistance training improves sleep quality in subjects with moderate Parkinson's disease. J Strength Cond Res 31(8): 2270-2277, 2017-The objectives of this study were to test if 12 weeks of progressive resistance training (RT) improves sleep quality and muscle strength in subjects with moderate Parkinson's disease (PD) and if sleep quality values of subjects with moderate PD are closer to those of age-matched healthy controls (HC) at posttraining. This was a randomized controlled trial conducted between March 2013 and September 2014. Twenty-two subjects with moderate PD were randomly assigned to a nonexercising control group (n = 11) or an RT group (n = 11). Thirty-one HC were not randomized to any group. The RT group performed a RT program twice a week for 12 weeks, whereas the control group made no change to their weekly routine. For subjects with PD, sleep quality (i.e., Pittsburgh Sleep Quality Index [PSQI]) and knee-extensor peak torque were assessed before and after 12 weeks of intervention; for HC, these outcomes were assessed at pretest only. There were differences between RT and control groups in PSQI scores, PSQI subscores(i.e., subjective sleep quality and daytime dysfunction), and knee-extensor peak torque at posttraining (p ≤ 0.05). After RT, the average subjects with PD showed lower (i.e., improved) PSQI scores than the average HC (p ≤ 0.05). A negative association was observed between changes in PSQI scores and changes in knee-extensor peak torque at posttraining (r = -0.58, p = 0.028). No adverse events were reported. The RT is recommended as an adjunct therapeutic method for improving sleep quality of subjects with moderate PD and moving these levels to those observed in HC.

Noninvasive assessment of respiratory muscle strength and activity in Myotonic dystrophy.

ObjectiveTo evaluate sensitivity/specificity of the maximum relaxation rate (MRR) of inspiratory muscles, amplitude of electromyographic activity of the sternocleidomastoid (SCM), scalene (SCA), parasternal (2ndIS) and rectus abdominis (RA) muscles; lung function and respiratory muscle strength in subjects with Myotonic dystrophy type 1 (DM1) compared with healthy subjects.Design and methodsQuasi-experimental observational study with control group. MRR of inspiratory muscles, lung function and amplitude of the electromyographic activity of SCM, SCA, 2ndIS and RA muscles during maximum inspiratory pressure (PImax), maximum expiratory pressure (PEmax) and sniff nasal inspiratory pressure (SNIP) tests were assessed in eighteen DM1 subjects and eleven healthy.ResultsMRR was lower in DM1 group compared to healthy (P = 0.001) and was considered sensitive and specific to identify disease in DM1 and discard it in controls, as well as SNIP% (P = 0.0026), PImax% (P = 0.0077) and PEmax% (P = 0.0002). Contraction time of SCM and SCA was higher in DM1 compared to controls, respectively, during PImax (P = 0.023 and P = 0.017) and SNIP (P = 0.015 and P = .0004). The DM1 group showed lower PImax (P = .0006), PEmax (P = 0.0002), SNIP (P = 0.0014), and higher electromyographic activity of the SCM (P = 0.002) and SCA (P = 0.004) at rest; of 2ndIS (P = 0.003) during PEmax and of SCM (P = 0.02) and SCA (P = 0.03) during SNIP test.ConclusionsMD1 subjects presented restrictive pattern, reduced respiratory muscle strength, muscular electrical activity and MRR when compared to higher compared to controls. In addition, the lower MRR found in MD1 subjects showed to be reliable to sensitivity and specificity in identifying the delayed relaxation of respiratory muscles.

1RM prediction: a novel methodology based on the force-velocity and load-velocity relationships.

This study aimed to evaluate the accuracy of a novel approach for predicting the one-repetition maximum (1RM). The prediction is based on the force-velocity and load-velocity relationships determined from measured force and velocity data collected during resistance-training exercises with incremental submaximal loads. 1RM was determined as the load corresponding to the intersection of these two curves, where the gravitational force exceeds the force that the subject can exert. The proposed force-velocity-based method (FVM) was tested on 37 participants (23.9±3.1year; BMI 23.44±2.45) with no specific resistance-training experience, and the predicted 1RM was compared to that achieved using a direct method (DM) in chest-press (CP) and leg-press (LP) exercises. The mean 1RM in CP was 99.5kg (±27.0) for DM and 100.8kg (±27.2) for FVM (SEE=1.2kg), whereas the mean 1RM in LP was 249.3kg (±60.2) for DM and 251.1kg (±60.3) for FVM (SEE=2.1kg). A high correlation was found between the two methods for both CP and LP exercises (0.999, p<0.001). Good agreement between the two methods emerged from the Bland and Altman plot analysis. These findings suggest the use of the proposed methodology as a valid alternative to other indirect approaches for 1RM prediction. The mathematical construct is simply based on the definition of the 1RM, and it is fed with subject's muscle strength capacities measured during a specific exercise. Its reliability is, thus, expected to be not affected by those factors that typically jeopardize regression-based approaches.