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Intense exercise training with insufficient recovery time is associated with reductions in neuromuscular performance. However, it is unclear how single muscle fibre mechanical function and myofibrillar Ca2+ sensitivity contribute to these impairments. We investigated the effects of overload training on joint-level neuromuscular performance and cellular-level mechanical function. Fourteen athletes (4 female and 10 male) underwent a 3-week intensified training protocol consisting of up to 150% of their regular training hours with three additional high-intensity training sessions per week. Neuromuscular performance of the knee extensors was assessed via maximal voluntary contraction (MVC) force, electrically evoked twitch contractions, and a force-frequency relationship. Muscle biopsies were taken from the vastus lateralis to assess single fibre mechanical function. Neither MVC force nor twitch parameters were altered following training (all p > 0.05), but a rightward shift in the force–frequency curve was observed with average reduction in force of 6%–27% across frequencies 5–20 Hz (all p < 0.05). In single fibres, maximal force output was not reduced following training, but there was a rightward shift in the force–pCa curve driven by a 6% reduction in Ca2+ sensitivity (p < 0.05). These data indicate intensified training leads to impaired Ca2+ sensitivity at the single fibre level, which in part explains impaired neuromuscular function at the joint level during lower frequencies of activation. This is an important consideration for athletes, as performance is often assessed at maximal levels of activation, and these underlying impairments in force generation may be less obvious. [ABSTRACT FROM AUTHOR] more...

The main objective of the research consists in providing evidence that a long-term rehabilitation protocol is favorable for the patient. In adult brachial plexus (BP) palsies, after several surgical attempts, the lack of results in the upper limb's functionality leads to less compliance to rehabilitation therapy. The upper limb's functionality of 22 patients with posttraumatic operated chronic BP paresis (either on the right or left, regardless the dominant limb) was assessed retrospectively. The patients were evaluated regarding MRC scaling, dynamometric tests and electroneuromyographic examination. All patients have gone through at least one rehabilitation interval (10 days) after an initial evaluation, and were evaluated again, by same methods, at a second session, at least 6 months later, but no more than one year. Mild and inconstant improvements were obtained in a total of 9 patients, especially in better dynamometric results and improved amplitudes of motor and sensory action potentials. The electrodiagnosis correlates with dynamometric parameters (muscle strength) and slight amelioration of the motor deficit. Given the small sample size as a limitation, as well as no standardized therapeutic protocol, it should be noted that the 9 patients were the only ones who either attended more than one interval or did more procedures as frequency in time (more often meaning 3 times weekly for 6 months, in 6 patients). Although the most frequent procedures were neuromuscular electrical stimulation (NMES) and proprioceptive neuromuscular facilitation (PNF), the results suggest that regardless of the techniques, the more active patients had better results. Proving the need for long-term rehabilitation, even contrary to the less visible results, can be the trigger point for future research and therapy strategies, as the results suggest central mechanisms involved, adding the cortical ongoing plasticity into the equation. [ABSTRACT FROM AUTHOR] more...

Objectives: Urinary incontinence is pelvic floor muscles dysfunction, most often caused by a weakening of their strength. There are no guidelines on how to evaluate pelvic floor muscle function. Palpation is the most popular method of assessing pelvic floor muscle function, but it is subjective. The aim of the study was to review the objective methods used in the assessment of pelvic floor muscle function in women with urinary incontinence. Material and methods: A systematic literature review of the PubMed database was performed using the following keywords: "Pelvic Floor"[mh] AND ("Pelvic Floor Disorders"[mh] OR "Urinary Incontinence"[mh]). The search was limited to English-language articles published from 2011 to 2021. Eligible were interventional studies in which the pelvic floor muscle function of women with urinary incontinence was assessed using quantitative tools. Methods that cannot be used in the clinic were excluded from the analysis. Results: Fifty-two articles were included in the analysis and five unique methods assessing the function of pelvic floor muscle were distinguished: manometry, electromyography (EMG), ultrasonography (USG), dynamometry, accelerometry. Conclusions: Manometry, EMG and USG are the most common objective methods of assessing pelvic floor muscle function. When taking measurements, it is important to choose the right position of the patient. The use of objective tools to assess the function of the pelvic floor muscle and obtaining quantitative and/or qualitative data allows us to precisely diagnose and monitor the treatment and rehabilitation progress. [ABSTRACT FROM AUTHOR] more...

Pelvic floor muscle (PFM) strength is a critical factor for optimal pelvic floor function. Fluctuations in strength values based on different phases of the menstrual cycle (MC) could signify a need for a paradigm shift in evaluating, approaching, and planning training. This research aims to examine and contrast the pelvic floor muscle strength during different phases of the menstrual cycle. A prospective observational study employing digital assessment with the modified Oxford scale and vaginal dynamometry measurements was performed, in order to assess the baseline strength and the contraction strength of the PFMs in eumenorrheic females at three different phases of the MC: the early follicular phase (EFP), the late follicular phase (LFP), and the mid-luteal phase (MLP). During two complete cycles, tympanic temperature and body weight were measured and the urinary luteinizing hormone concentration was tested to determine the time of ovulation. In total, 216 dynamometric measurements of PFM strength were obtained from eighteen nulliparous women (25.72 ± 5.03 years). There were no differences between the baseline strength (p = 0.886) and the contraction strength (p = 0.756) with the dynamometric speculum. In the post hoc analysis, the baseline strength, contraction strength, and strength showed no significant differences between MC phases. As no differences in PFM strength in women were found, the PFMs do not seem to be weaker at any time during the menstrual cycle. It appears that the assessment, establishment, and monitoring of a PFM training program could be initiated at any point in the cycle. [ABSTRACT FROM AUTHOR] more...

Background: Sarcopenia is a comorbidity associated with heart failure, which aggravates its prognosis. Objectives: To analyze the differential characteristics of polypathological patients with acute heart failure (AHF) based on the presence of low muscle strength, as well as to study whether this condition is associated with a worse prognosis. Methods: An observational study of 377 patients with a diagnosis of acute heart failure from the prospective multicentric PROFUND-IC registry was carried out. The main variable is low muscle strength, which is assessed with dynamometry or prehensile strength. Epidemiological and anthropometric characteristics, as well as associated comorbidities, were analyzed. Likewise, the etiology of the AHF episode, the number of admissions in the previous year, and the NYHA scale were also included. Finally, scores on functionality, treatment established, and mortality and readmission rates were studied. Quantitative variables are described as mean, and standard deviation, and qualitative variables are expressed as absolute numbers and percentages. A descriptive and bivariate analysis was performed according to the presence of low muscle strength (handgrip <27 kg in men and <16 kg in women), using the Welch test for quantitative measures and Chi-square for qualitative variables. In addition, Kaplan-Meier curves of readmission and mortality and a logistic regression analysis were also performed. Results: 377 patients were included (56% female, mean age 83 years). 310 (82.23%) had low muscle strength. Those with low muscle strength were older (84 vs. 78 years, p < 0.001), with more cognitive impairment (11.9% vs. 0%, p = 0.021), worse functional class (p = 0.016), lower scores in the Barthel index and Rockwood scale (p < 0.001), and higher in the PROFUND index (p < 0.001). They had higher rates of readmission and mortality without statistically significant differences. The PROFUND index is significantly associated with low muscle strength (OR 1.19, CI (1.09–1.31), p < 0.001). Conclusions: Elderly polypathological patients with acute heart failure and low muscle strength have a higher PROFUND index and a lower probability of survival per year. [ABSTRACT FROM AUTHOR] more...

Physical fitness, encompassing cardiorespiratory endurance, muscular strength, and body composition, is vital for health and well-being. Muscular fitness, in particular, is associated with decreased risks of depression, cognitive disorders, and metabolic disease. Despite various available tests to measure muscle strength, there is no consensus on the most effective test or combination of tests, and direct comparisons are scarce. This study evaluated the muscular fitness of 484 children aged 9-12 years (225 girls and 259 boys) through multiple tests, including standing broad jump (SBJ), push-ups, bent-arm hang (BAH), sit-ups, handgrip strength, back-leg dynamometry (back-leg), and medicine ball throw (MBT), to assess their correlation with anthropometric data. Our correlation analysis revealed strong relationships (r > 0.6) between handgrip and MBT, handgrip and back-leg, and MBT and back-leg. However, most correlations were weak or very weak, indicating that different aspects of muscle strength, as assessed by these tests, are largely independent and cannot be substituted for one another. This underscores the necessity of employing a variety of tests in the comprehensive assessment of muscular fitness, taking into account the unique predictive value of each. [ABSTRACT FROM AUTHOR] more...

Lower limb injury rates have increased dramatically in line with increased female sport participation levels. Muscle strength is a modifiable lower limb injury risk factor, guiding performance monitoring and rehabilitation. The aim of this study was to investigate the test-retest reliability of isokinetic and isometric lower limb peak torque to body mass of muscles acting on the hip, knee, and ankle in female team sport athletes. It was hypothesised the test-retest reliability would be good (intraclass correlation coefficients (ICC) ≥ 0.75). Thirty-eight female athletes (Australian Rules Football = 18, netball = 12, soccer = 8) aged 16–35 years participated in this study. Participants performed isokinetic (60°/s and 120°/s) and isometric testing on a Biodex Isokinetic Dynamometer on three separate days. Poor to good reliability was demonstrated for all joint movements (ICC = 0.38–0.88) with small to moderate effect sizes (0.00–0.43) and typical errors (5.65–24.49). Differences in peak torque to body mass were observed between sessions one and two and/or one and three, demonstrating a learning effect. Therefore, three testing sessions, and/or the inclusion of a familiarisation session, is recommended for future assessments in populations unfamiliar with dynamometry. • Lower limb strength does not comprise of just a single joint (hip, knee and ankle). • Differences in peak torque between sessions demonstrate potential learning effects. • In future, a familiarisation session or three testing sessions are recommended. [ABSTRACT FROM AUTHOR] more...

This study compared handheld dynamometry (HHD) at the weakest point of the strength curve for hip extensors, hip abductors, and knee extensors in older adults and onerepetition maximum (1RM) of that same muscle groups with cuff weights. Fifty participants (62-94 years) were tested. Paired t tests indicated no significant differences between the 2 measures. Reliability testing for absolute agreement between 1RM and HHD yielded intraclass correlations of good to excellent. This demonstrates HHD at or near the weakest point of a muscle group provides an accurate measure of older individual's 1RM for knee extension, hip extension, and hip abduction. [ABSTRACT FROM AUTHOR] more...

This study aimed to assess the combination of video-based kinematic variables adjusted by intrinsic covariates to predict the relative eccentric force (RelF) during the Nordic curl. The participants (n = 21) performed Nordic curls (3 trials; 3-min rest) on a device measuring the eccentric force. The peaks were normalized by body weight. Kinovea software was used to track angular and linear velocity and acceleration from recorded videos. Two prediction models with multiple linear regression equations associated kinematic, anthropometric, and age variables to adjust the actual RelF. The equations obtained the predicted RelF. The actual RelF was inversely correlated with height (r = −.52), tangential (r = −.50) and centripetal accelerations (r = −.715), and angular velocity (r = −.70). The best prediction models combined angular velocity with age (F2,18 = 15.1, P =.001, r =.792, r2 =.627) and with height (F2,18 = 14.5, P =.001, r =.785, r2 =.616). No differences were observed between actual and predicted values (P =.993−.994), with good levels of agreement and consistency (intraclass correlation coefficient =.77−.78; Cronbach α =.86−.87). Bland–Altman results showed high levels of agreement and low biases. The standard error of measurement and minimal detectable change ranges were 0.46 to 0.49 N/kg and 1.28 to 1.36 N/kg, respectively. Also, the percentage of standard error of measurement was below 10% (7.92%–8.35%). The coefficient of variation analysis returned a 14.54% and 15.13% for each model, respectively. Kinematic analysis offers portability and low cost to current expensive or technical impaired dynamometry-based techniques to assess the RelF. [ABSTRACT FROM AUTHOR] more...

Overhead athletes require strenuous shoulder activity in nonneutral cervical spine positions to eccentrically decelerate the throwing/striking arm following ball release/contact. We therefore aimed to compare eccentric shoulder rotation strength through a 90° arc between neutral and rotated positions. Fifty-two participants (19 M, 34 F 170±10 cm; 73±18 kg, 21.9±2.9 years) without shoulder or cervical spine pathology participated. Isokinetic eccentric shoulder rotation strength was measured through a 90° arc with the shoulder elevated 90° in frontal plane (frontal plane), and 45° anterior to the frontal plane (scapular plane) in neutral and rotated cervical spine positions. Cervical spine position was obtained by instructing participants to maximally rotate their respective side. Frontal plane eccentric external rotated strength differed between neutral and contralaterally positions in the first 10° of the motion, near forearm vertical (p+=+0.029). Internal rotation strength differed between neutral and contralaterally rotated positions from 55–60° external rotation (p+=+0.004). Scapular plane eccentric external rotation differed between cervical positions between 21–67° shoulder external rotation (p<0.001). Scapular plane internal rotation strength differed between cervical positions between 22–60° shoulder external rotation (p<0.001). In populations requiring strenuous use of their shoulders in altered cervical spine positions, sports medicine clinicians should consider including strength testing that reflects the functional positions of their patients during an orthopedic examination. [ABSTRACT FROM AUTHOR] more...

The aim of this review is to evaluate existing isokinetic testing protocols for the shoulder in tactical occupations, document their shoulder strength profiles, and determine any associations to shoulder injury. Four electronic databases were searched (Medline/Pubmed, Ovid/Emcare, CINAHL/Ebsco and Embase) using the keywords police OR law enforcement, firefighter, military, AND isokinetic. Articles were eligible if they had at least one cohort of a tactical population and included isokinetic testing of the glenohumeral joint. The search yielded 275 articles. After screening for duplicates and inclusion criteria, 19 articles remained for review, six of which assessed injury correlation. 17 articles evaluated military personnel and two examined firefighters. Articles were categorized by study design, population, isokinetic protocols, strength outcome measures and statistical measures. Concentric internal rotation (IR) and external rotation (ER) strength at 60 degrees/second were reported most frequently (84% of cases). There was a paucity of testing speeds, repetition ranges and contraction types evaluated when compared to existing literature in other populations with high shoulder injury occurrence such as overhead and collision athletes. Outside of military cohorts, there is limited data available to characterise the isokinetic strength profile of the shoulder in tactical occupations. Meta-analysis for injury association was unable to be performed due to independent variable and statistical heterogeneity. However, a best evidence synthesis suggested conflicting evidence to support the association of injury with isokinetic strength testing in tactical populations. Future studies should prioritise prospective designs utilising variable speeds, repetition schemes and contraction types to better capture the dynamic occupational demands in tactical groups. [ABSTRACT FROM AUTHOR] more...

Background: Muay Thai, Thailand’s national sport, widely practiced globally, is known for using sports liniment before training and fights. A popular product is ‘Namman Muay’, an iconic symbol of Thailand, though its direct impact on performance lacks research. Objectives: Investigate the impact of Namman Muay on the rectus femoris of the dominant leg. Focus on muscular strength exercises – seated hip flexion and supine knee extension – with relative strength as the primary outcome. Material and Methods: A randomised control trial with 24 male Muay Thai fighters, divided into 12 in the Baby Oil (BO) and 12 in the Namman Muay (NM) group. Both groups received effleurage massage on the dominant kicking legs, followed by a RAMP warm-up. Performance measurements using Lafayette Handheld Dynamometer evaluated two isometric strength tests. Results: NM intervention showed significant increases in hip flexion and knee extension strength. Within groups, a 3% decrease was seen in the BO and an 11.6% increase in NM for hip flexion strength, and 1% decrease in BO and 6.9% increase in NM for knee extension strength. Conclusion: This study provides valuable insight to Muay Thai fighters and trainers, showing that 5 ml NM boosts relative muscular strength of hip flexion and knee extension. This could improve male Muay Thai fighters’ performance particularly when using kicking techniques. more...

This study aimed to assess the test–retest reliability of a Wii board–based device to assess the eccentric knee strength. Healthy participants (n = 20, 22.7 [3.4] y, 1.71 [0.09] m, 69 [13] kg) performed 2 assessments—days 1 and 2—of the Nordic hamstring exercise (3 trials per day, 3 min of rest between trials, and 48 h between trials) on a padded board with an attached Wii Balance Board (WBB). A ratchet inelastic strap made the contact between the participant’s distal aspect of both legs and the inverted upper surface of the WBB. The means among 3 trials were used to extract the absolute strength and the left and the right limb strengths. No between-session differences were found (P range = .691–.981). The intraclass correlation coefficient range showed excellent results (.905–.926), as the Cronbach α test (above .94). The correlation was high (r > .91; .820 < r2 < .862). The Bland–Altman analysis returned high levels of agreement. The standard error of measurement ranged from 5.56 to 11.07 N and the minimal detectable change from 15.42 to 30.68 N. The percentage of standard error of measurement values were 2.95%, 3.74%, 2.88%, respectively, for absolute strength, right limb strength, and left limb strength. The adapted system showed an excellent cost–benefit relationship with optimal test–retest reliability. The findings suggest that the adapted system, using the WBB, is a reliable method for measuring the eccentric knee strength. [ABSTRACT FROM AUTHOR] more...

Background: Exercise can stress the pelvic floor muscles (PFMs). This study sought to assess the strength of the PFMs according to the level of physical exercise. Methods: An analytical observational study was carried out using digital palpation and dynamometry measurements to assess PF strength. Healthy nulliparous women were stratified according to physical exercise (physically active and sedentary) and level of physical exercise (elite, amateur, and sedentary). Results: Fifty-four women were analyzed, with a mean age of 25.64 (5.33) years and a BMI of 21.41 (2.96) kg/m2. Differences in the passive force and strength were observed between both groups of women (p < 0.05), and the strength was around two times higher in physically active women (p < 0.05). The strength was similar between elite female athletes and sedentary women (p > 0.05), but statistical differences were found with amateurs (p < 0.05). The PFM strength (p = 0.019) of elite female athletes (0.34 N) was almost half that of amateurs (0.63 N) and twice as strong as that of sedentary women (0.20 N). However, these differences were not significant using digital palpation (p = 0.398). Conclusions: Women who exercise generally have greater PFM strength than women who do not exercise. Physical exercise could strengthen the PFM; however, the high intensity demanded by high-level sports does not seem to proportionally increase the strength of the PFMs. [ABSTRACT FROM AUTHOR] more...

To assess the relationship among measurements of strength, function, and quality of life in an amyotrophic lateral sclerosis (ALS) clinical trial. In the FORTITUDE-ALS clinical trial (NCT03160898), 456 participants in the full-analysis set were treated with either reldesemtiv or placebo for 12 weeks; this post hoc analysis included all participants regardless of treatment assignments. Assessments included slow vital capacity (SVC), the ALS Functional Rating Scale-Revised (ALSFRS-R), and the 5-item ALS Assessment Questionnaire (ALSAQ-5). Muscle strength was measured quantitatively with hand-held dynamometry, and grip strength with a dedicated dynamometer. The relationship between strength and ALSFRS-R fine and gross motor domain scores, or responses to ALSAQ-5 questions on hand function and walking, was assessed with Spearman's rank correlation. The relationship between mean upper- or lower-extremity muscle strength and specific ALSFRS-R domains was modeled using principal-components analysis. Upper-extremity muscle strength and hand grip were highly correlated with ALSFRS-R fine motor scores and the ALSAQ-5 hand function question. Similarly, lower-extremity strength correlated well with ALSFRS-R gross motor domain and the ALSAQ-5 walking question. For SVC, correlation was poor with the ALSFRS-R respiratory domain, but stronger with the total score, potentially reflecting the insensitivity of the respiratory questions in the scale. Upper- and lower-extremity strength were both strong predictors of ALSFRS-R domain scores. In this analysis of data from an ALS clinical trial, muscle strength quantified by dynamometry was strongly correlated with functional capacity. These results suggest that muscle strength directly relates to specific functions of importance to people with ALS. [ABSTRACT FROM AUTHOR] more...

Introduction and hypothesis: The aim of this study was to examine the impact of a single running session on pelvic floor morphology and function in female runners, and to compare those with and without running-induced stress urinary incontinence (RI-SUI). Methods: This cross-sectional, observational study involved two groups: female runners who regularly experienced RI-SUI (n = 19) and runners who did not (n = 20). Pelvic floor muscle (PFM) properties were assessed using intravaginal dynamometry during maximal voluntary contractions (MVC) and during passive tissue elongation. The morphology of the pelvic floor was assessed at rest, during MVC and during maximal Valsalva maneuver (MVM) using 2D and 3D transperineal ultrasound imaging before and after a running protocol. Mixed-effects ANOVA models were used to compare all outcomes between groups and within-groups, including the interaction between group and time. Effect sizes were calculated. Results: No changes in PFM function assessed using intravaginal dynamometry were observed in either group after the run. Significant and large within-group differences were observed on ultrasound imaging. Specifically, the area and antero-posterior diameter of the levator hiatus were larger after the run, the bladder neck height was lower after the run, and the levator plate length was longer after the run (p ≤ 0.05). At the peak MVM and MVC, the bladder neck height was lower after the run than before the run (p ≤ 0.05). No between-group differences were observed for any outcomes. Conclusions: Running appears to cause transient strain of the passive tissues of the female pelvic floor in runners both with and without RI-SUI, whereas no concurrent changes are observed in PFM contractile function. [ABSTRACT FROM AUTHOR] more...

The article presents a mathematical model and algorithm for adjusting the depth of plunger suspension to prevent it from exiting the pump cylinder. Iterative calculation of theoretical dynamic dynamometer cards is performed, with adjustment for the determined correction of plunger suspension depth and the assessment of normal operation of pumping equipment. The model and algorithm are tested on the example of wells of the Uzen oil field. [ABSTRACT FROM AUTHOR] more...

The aging process is commonly accompanied by a general or specific loss of muscle mass, force and/or function that inevitably impact on a person’s quality of life. To date, various clinical tests and assessments are routinely performed to evaluate the biomechanical status of an individual, to support and inform the clinical management and decision-making process (e.g., to design a tailored rehabilitation program). However, these assessments (e.g., gait analysis or strength measures on a dynamometer) are typically conducted independently from one another or at different time points, providing clinicians with valuable yet fragmented information. We hereby describe a comprehensive protocol that combines both in vivo measurements (maximal voluntary isometric contraction test, superimposed neuromuscular electrical stimulation, electromyography, gait analysis, magnetic resonance imaging, and clinical measures) and in silico methods (musculoskeletal modeling and simulations) to enable the full characterization of an individual from the biomechanical standpoint. The protocol, which requires approximately 4 h and 30 min to be completed in all its parts, was tested on twenty healthy young participants and five elderlies, as a proof of concept. The implemented data processing and elaboration procedures allowing for the extraction of several biomechanical parameters (including muscle volumes and cross-sectional areas, muscle activation and co-contraction levels) are thoroughly described to enable replication. The main parameters extracted are reported as mean and standard deviation across the two populations, to highlight the potential of the proposed approach and show some preliminary findings (which were in agreement with previous literature). more...

The main objective of the research consists in providing evidence that a long-term rehabilitation protocol is favorable for the patient. In adult brachial plexus (BP) palsies, after several surgical attempts, the lack of results in the upper limb’s functionality leads to less compliance to rehabilitation therapy. The upper limb’s functionality of 22 patients with posttraumatic operated chronic BP paresis (either on the right or left, regardless the dominant limb) was assessed retrospectively. The patients were evaluated regarding MRC scaling, dynamometric tests and electroneuromyographic examination. All patients have gone through at least one rehabilitation interval (10 days) after an initial evaluation, and were evaluated again, by same methods, at a second session, at least 6 months later, but no more than one year.. Mild and inconstant improvements were obtained in a total of 9 patients, especially in better dynamometric results and improved amplitudes of motor and sensory action potentials. The electrodiagnosis correlates with dynamometric parameters (muscle strength) and slight amelioration of the motor deficit. Given the small sample size as a limitation, as well as no standardized therapeutic protocol, it should be noted that the 9 patients were the only ones who either attended more than one interval or did more procedures as frequency in time (more often meaning 3 times weekly for 6 months, in 6 patients). Although the most frequent procedures were neuromuscular electrical stimulation (NMES) and proprioceptive neuromuscular facilitation (PNF), the results suggest that regardless of the techniques, the more active patients had better results. Proving the need for long-term rehabilitation, even contrary to the less visible results, can be the trigger point for future research and therapy strategies, as the results suggest central mechanisms involved, adding the cortical ongoing plasticity into the equation. more...

Pelvic floor muscle (PFM) strength is a critical factor for optimal pelvic floor function. Fluctuations in strength values based on different phases of the menstrual cycle (MC) could signify a need for a paradigm shift in evaluating, approaching, and planning training. This research aims to examine and contrast the pelvic floor muscle strength during different phases of the menstrual cycle. A prospective observational study employing digital assessment with the modified Oxford scale and vaginal dynamometry measurements was performed, in order to assess the baseline strength and the contraction strength of the PFMs in eumenorrheic females at three different phases of the MC: the early follicular phase (EFP), the late follicular phase (LFP), and the mid-luteal phase (MLP). During two complete cycles, tympanic temperature and body weight were measured and the urinary luteinizing hormone concentration was tested to determine the time of ovulation. In total, 216 dynamometric measurements of PFM strength were obtained from eighteen nulliparous women (25.72 ± 5.03 years). There were no differences between the baseline strength (p = 0.886) and the contraction strength (p = 0.756) with the dynamometric speculum. In the post hoc analysis, the baseline strength, contraction strength, and strength showed no significant differences between MC phases. As no differences in PFM strength in women were found, the PFMs do not seem to be weaker at any time during the menstrual cycle. It appears that the assessment, establishment, and monitoring of a PFM training program could be initiated at any point in the cycle. more...

Purpose: Concentric hip and eccentric knee joint mechanics affect sprint performance. Although the biarticular hamstrings combine these capacities, empirical links between swing phase mechanics and corresponding isokinetic outcome parameters are deficient. This explorative study aimed (1) to explain the variance of sprint velocity, (2) to compare maximal sprints with isokinetic tests, (3) to associate swing phase mechanics with isokinetic parameters, and (4) to quantify the relation between knee and hip joint swing phase mechanics. Methods: A total of 22 sprinters (age = 22 y, height = 1.81 m, weight = 77 kg) performed sprints and eccentric knee flexor and concentric knee extensor tests. All exercises were captured by 10 (sprints) and 4 (isokinetics) cameras. Lower-limb muscle balance was assessed by the dynamic control ratio at the equilibrium point. Results: The sprint velocity (9.79 [0.49] m/s) was best predicted by the maximal knee extension velocity, hip mean power (both swing phase parameters), and isokinetic peak moment of concentric quadriceps exercise (R2 = 60%). The moment of the dynamic control ratio at the equilibrium point (R2 = 39%) was the isokinetic parameter with the highest predictive power itself. Knee and hip joint mechanics affected each other during sprinting. They were significantly associated with isokinetic parameters of eccentric hamstring tests, as well as moments and angles of the dynamic control ratio at the equilibrium point, but restrictedly with concentric quadriceps exercise. The maximal sprints imposed considerably higher loads than isokinetic tests (eg, 13-fold eccentric knee joint peak power). Conclusions: Fast sprinters demonstrated distinctive knee and hip mechanics in the late swing phase, as well as strong eccentric hamstrings, with a clear association to the musculoarticular requirements of the swing phase in sprinting. The transferability of isokinetic knee strength data to sprinting is limited inter alia due to different hip joint configurations. However, isokinetic tests quantify specific sprint-related muscular prerequisites and constitute a useful diagnostic tool due to their predicting value to sprint performance. [ABSTRACT FROM AUTHOR] more...

Background and Study Aim: Long-term trends in muscular fitness show a gradual decline, which has become even more intense due to the Covid-19 pandemic. Declines in muscular fitness are associated with deteriorated health and well-being parameters. It is crucial to monitor this decline and appropriate tests need to be selected and interpreted correctly. The aim of this research was to apply muscle fitness tests and compare the development of performance between 9 and 12-year-olds and, at the same time, to compare performance differences between boys and girls. Material and Methods: 225 girls and 259 boys aged 9 to 12 years (11.1 ± 0.9) took part in the studies. Seven tests were selected to assess muscular fitness: bent-arm hang (BAH), push-ups, sit-ups, standing broad jump (SBJ), medicine ball throw (MBT), handgrip dynamometry (handgrip), and pulling back-leg dynamometry (back-leg). Results: The results showed that the development curves of muscle tests are incomparable. A linear increase was recorded for the MBT test. The handgrip, back-leg, and MBT tests have similar development although they do not test the same type of force. A very different trend (stagnation, decline) was found for the BAH and push-up tests. Girls and boys showed a comparable trend in all tests, however, boys always had higher absolute performances. Conclusions: Our data are intended to contribute to the expert discussion on the choice of muscular fitness tests. Based on these results, the selection of multiple tests may be recommended for optimal assessment of muscular fitness. In future research, it would be advisable to follow up by testing a larger cohort. more...

Abstract Background The level of quadriceps strength (QS) generated in the supine or seated position is not similar. For QS follow-up from intensive care unit (ICU) stay to recovery, getting comparable measures is essential. This study aimed to develop and validate new equations for estimating QS in a given position based on the measurement taken in another one. Methods and results Isometric QS was measured using a handheld dynamometer and a standardized protocol in a supine and in a seated position. In a first cohort of 77 healthy adults, two QS conversion equations were developed using a multivariate model integrating independent parameters such as age, sex, body mass index (BMI) and baseline QS. These equations were tested in two cohorts for external validation, using the interclass correlation coefficient (ICC) and Bland–Altman graphical method. Only one was validated in the second cohort (62 different healthy adults): the ICC was 0.87 (95% CI 0.59–0.94) and the bias was − 0.49 N/Kg (limits of agreement: − 1.76–0.78 N/kg). However, this equation did not perform well in the third cohort (50 ICU survivors): the ICC was 0.60 (95% CI 0.24–0.78), and the bias was − 0.53 N/Kg (limits of agreement: − 1.01–2.07 N/kg). Conclusions As no conversion equation has been validated in the present study, repeated QS measurements should be performed strictly in the same standardized and documented position. more...

During space flight, the changes in the functions of the upper limbs can affect the quality of operator activity. At the same time, there are very few data on this topic, because most of the research is focused on the structure and functions of the lower extremities. The aim was to study the characteristics of the grip force control during the decrease of the support and proprioceptive sensory signals in the conditions of the ground-based model of the effects of space flight, Dry Immersion (DI). The duration of DI exposure was 21 days. 10 male volunteers performed tests using a hand dynamometer for maximal voluntary contraction, the maintenance of the reference force, the reproduction of this force from memory, and the grip force gradation test. The subjects performed this series of tests before exposure to DI, then on days 1, 3, 5, 10, 15, and 20 of DI, and days 1 and 3 of the recovery period. The results show that DI exposure led to an increase in proprioceptive sensitivity in the tasks without visual feedback when with open eyes from day 5 of DI the subjects made more mistakes in the reproduction of the reference force using the dominant hand. The sensory processing/modulation disorder under DI factors may cause this phenomenon. [ABSTRACT FROM AUTHOR] more...

Introduction/Aims: Muscle weakness, and its association with mobility limitations, has received little study in oculopharyngeal muscular dystrophy (OPMD) using quantitative and standardized assessments. The objectives of this study were to (1) document upper and lower limb muscle strength, upper limb functions, fatigue, and mobility capacities; (2) compare them with reference values and across participant age groups; and (3) explore associations between muscle strength, fatigue, and mobility capacities among adults with OPMD. Methods: Thirty‐four participants were included in this cross‐sectional study. The following variables were assessed: quantitative maximal isometric muscle strength, grip and pinch strength, fatigue, walking speed, walking endurance, sit‐to‐stand, and stair ascent and descent capacities. Results: Muscle strength was lower for older than younger participants for five muscle groups (P <.05). Walking endurance, sit‐to‐stand, stairs (ascent and descent), and strength of hip flexion, grip, and pinch were below 80% of reference values in participants ≥56 y old (55.3%–78.2%). Moderate to strong correlations were found between muscle strength and mobility capacities (ρ = 0.42–0.80, P <.05), and between fatigue and either muscle strength or mobility capacities (ρ = 0.42–0.75, P <.05). Discussion: This study highlights the impact of OPMD on strength, endurance, and functional capacity, among others, with patients being well below reference values even before the age of 65 y. In addition to helping health professionals to offer better clinical guidance, these results will improve clinical trial readiness. The next steps will be to assess the metrological properties of outcome measures and continue to document the disease progression rate. [ABSTRACT FROM AUTHOR] more...

Neuromuscular disorders show extremely varied expressions of different symptoms and the involvement of muscles. Non-invasively, myotonia and muscle stiffness are challenging to measure objectively. Our study aims to test myotonia, elasticity, and stiffness in various neuromuscular diseases and to provide reference values for different neuromuscular disease groups using a novel handheld non-invasive myometer device MyotonPRO®. We conducted a monocentric blinded cross-sectional study in patients with a set of distinct neuromuscular diseases (NCT04411732, date of registration June 2, 2020). Fifty-two patients in five groups and 21 healthy subjects were enrolled. We evaluated motor function (6-min walk test, handheld dynamometry, Medical Research Council (MRC) Scale) and used ultrasound imaging to assess muscle tissue (Heckmatt scale). We measured muscle stiffness, frequency, decrement, creep, or relaxation using myotonometry with the device MyotonPRO®. Statistically, all values were calculated using the t test and Mann–Whitney U test. No differences were found in comparing the results of myotonometry between healthy and diseased probands. Furthermore, we did not find significant results in all five disease groups regarding myotonometry correlating with muscle strength or ultrasound imaging results. In summary, the myometer MyotonPRO® could not identify significant differences between healthy individuals and neuromuscular patients in our patient collective. Additionally, this device could not distinguish between the five different groups of disorders displaying increased stiffness or decreased muscle tone due to muscle atrophy. In contrast, classic standard muscle tests could clearly decipher healthy controls and neuromuscular patients. [ABSTRACT FROM AUTHOR] more...

* OBJECTIVE: To summarize the evidence on reliability and criterion validity of hip muscle strength testing using portable dynamometers. * DESIGN: Systematic review with meta-analysis. * LITERATURE SEARCH: Five databases were searched from inception to March 2023. * STUDY SELECTION CRITERIA: We included studies investigating reliability or criterion validity of hip flexor, extensor, abductor, adductor, or internal/external rotator strength testing with portable dynamometers in injury-free individuals or those with pelvic/ lower limb musculoskeletal disorders. * DATA SYNTHESIS: We performed meta-analyses for each muscle group, position, and method of fixation. We rated pooled results as sufficient (>75% of studies with correlations >0.70), insufficient (>75% of studies with correlations <0.70), or inconsistent (sufficient/insufficient results). We assessed the quality of evidence, created evidence gap maps, and made clinical recommendations. * RESULTS: We included a total of 107 studies (reliability 103, validity 14). The intrarater and interrater reliability for hip muscle strength testing across different positions and methods of fixation was sufficient (intraclass correlation coefficient = 0.78-0.96) with low- to high-quality evidence. Criterion validity was less investigated and mostly inconsistent (very low-to moderate-quality evidence) with a wide range of correlations (r = 0.40-0.93). * CONCLUSION: Hip muscle strength testing using portable dynamometers is reliable. The use of portable dynamometers as clinical surrogates for measuring strength using an isokinetic dynamometer requires further investigation. Clinicians testing hip muscle strength with portable dynamometers should use external fixation seated for hip flexors, prone or supine for hip extensors, side-lying or supine for abductors and adductors, and prone and seated for internal and external rotators. [ABSTRACT FROM AUTHOR] more...

Objective: To investigate the differences in pelvic floor muscle (PFM) morphology and function between female runners with and without running‐induced stress urinary incontinence (RI‐SUI). Design: This was a cross‐sectional, observational study. Methods: Experienced female runners were recruited into two groups: runners who regularly experience RI‐SUI (n = 19) and runners who do not (n = 20). Active and passive pelvic floor muscle (PFM) properties were assessed using intravaginal dynamometry during maximal voluntary contractions (MVC) and during passive tissue elongation. The morphology of the urethra and PFMs was assessed using 2D and 3D transperineal ultrasound imaging. Independent t tests or Mann–Whitney U were used as appropriate to test group differences on all study outcomes, and Cohen's d effect sizes were calculated. Results: The rate of force development during the MVC was significantly higher in participants reporting RI‐SUI (p ≤ 0.05) and conversely, significantly lower during passive elongation of the PFMs (p ≤ 0.05) compared to runners with no history of leakage. Concurrently, the extent of bladder neck elevation between rest and maximum voluntary activation was significantly higher among those with RI‐SUI compared to those without. Although not significant, small to moderate effect sizes were observed for other outcomes—active force outcomes measured during MVC tended to be higher in runners with RI‐SUI, while passive force outcomes measured during passive tissue elongation tended to be lower. The cross‐sectional area of the urethral wall and the area of the levator hiatus tended to be larger in runners with RI‐SUI compared to those without. Conclusion: Runners who experience RI‐SUI demonstrate better PFM contractile function but lower passive support when compared to their continent counterparts. [ABSTRACT FROM AUTHOR] more...

Introduction and aim. Rheumatoid arthritis is a chronic progressive systemic disease of the connective tissue affecting the joints, mainly small, of the erosive-destructive polyarthritis type, and frequent systemic inflammatory damage to internal organs. The purpose of the research is to evaluate the effectiveness of physical therapy on the muscles of upper limbs in patients with rheumatoid arthritis by the dynamics of muscle strength and strength index. Material and methods. To determine the strength of the muscles of the affected upper limbs were used dynamometry, calculated strength index as a percentage to assess the functional ability of the affected limb. All patients were divided into control (n=92) and main (n=96) groups, taking into account the functional insufficiency of the joints. Results. After 6 months of physical therapy, muscle strength indicators in the main group of patients with 1st degree of functional joints insufficiency (FJI) in the affected right limb increased by 3.1 kg, in the left by 3 kg; with 2nd degree FJI - in the right limb by 4.2 kg, in the left - by 3.7 kg, significantly exceeded the same indicators in patients of the control group (p<0.05). Similarly, there was an increase in the strength index in the patients of the main group. Conclusion. Physical therapy technology has been developed and implemented effectively influenced the increase in muscle strength and strength index of affected upper limbs of the main group of patients with rheumatoid arthritis. [ABSTRACT FROM AUTHOR] more...

Context: Hip pain is associated with reduced hip muscle strength, range of movement (ROM), and decreased postural stability. Singleleg squat is a reliable and valid method to measure dynamic balance. Objective: To evaluate the influence of physical characteristics and use of a decline board on squat performance in a hip pain population. Design: Cross-sectional study setting. Clinical Patients: In total, 33 individuals scheduled for arthroscopic hip surgery were matched with 33 healthy controls. Interventions: Hip and ankle ROM, hip strength, and trunk endurance were assessed, along with knee and trunk kinematics during squat on flat and 25° decline surfaces. Main Outcome Measures: Between-group and surface differences in alignment, between-group strength and ROM, and associations between alignment and physical characteristics were assessed and determined using mixed model analysis of variance and Pearson R. Results: The hip pain group had significantly less strength and ROM for all directions except abduction strength and ankle dorsifiexion (P > .02). No differences existed between lire 2 groups for trunk (P < .70) or knee displacement (P < .46) during squat on either surface. When the 2 groups were combined (n = 66), decline squat significantly reduced knee medial displacement in both limbs by approximately 1 cm (P < .01). Decline squat reduced uxink lateral movement on 1 side only (P = .03). Reduced knee displacement during decline squat showed fair association with less hip-extension strength (r = -29), hip-flexion strength (r = -.25), and less dorsifiexion (r = -.24). Strength and range were not associated with trunk displacement. Conclusions: Decline squat reduced medial knee and lateral trunk displacement regardless of hip pain. Reductions may be greater in those with lesser hip muscle strength and dorsifiexion. Use of a decline board during squat for improving knee and trunk alignment should be considered as a goal of exercise intervention. [ABSTRACT FROM AUTHOR] more...

Context: Resistance training exercise prescription is often based on exercises performed at a percentage of a 1-repetition maximum (1RM). Following knee injury, there is no consensus when a patient can safely perform 1RM testing. Resistance training programs require the use of higher loads, and loads used in knee injury rehabilitation may be too low to elicit gains in strength and power. A maximum isometric contraction can safely be performed during early stages of knee rehabilitation and has potential to predict an isotonic knee extension 1RM. Objective: To determine whether a 1RM on an isotonic knee extension machine can be predicted from isometric peak torque measurements. Design: Descriptive laboratory study. Setting: University research laboratory. Participants: A total of 20 (12 males and 8 females) healthy, physically active adults. Main outcome measures: An isokinetic dynamometer was used to determine isometric peak torque (in N⋅m). 1RM testing was performed on a knee extension machine. Linear regression was used to develop a prediction equation, and Bland-Altman plots with limits of agreement calculations were used to validate the equation. Results: There was a significant correlation (P < .001, r = .926) between peak torque (283.0 [22.6] N⋅m) and the knee extension 1RM (69.1 [22.6] kg). The prediction equation overestimated the loads (2.3 [9.1] kg; 95% confidence interval, -15.6 to 20.1 kg). Conclusions: The results show that isometric peak torque values obtained on an isokinetic dynamometer can be used to estimate 1RM values for isotonic knee extension. Although the prediction equation tends to overestimate loads, the relatively wide confidence intervals indicate that results should be viewed with caution. [ABSTRACT FROM AUTHOR] more...

Context: Previous investigations have examined the reliability, normalization, and underlying projection mechanics of the seated single-arm shot-put (SSASP) test. Although the test is believed to reflect test limb strength, there have been no assessments determining whether test performance is directly associated with upper-extremity strength. Objective: To determine the relationship between isokinetic pushing force and SSASP performance and conduct a method comparison analysis of limb symmetry indices between the 2 tests. Design: Controlled laboratory study. Setting: Biomechanics laboratory. Patients (or Other Participants): Twenty-four healthy and physically active men (n = 12) and women (n = 12). Intervention(s): Participants completed the SSASP and isokinetic pushing tests using their dominant and nondominant arms. Main Outcome Measures: SSASP distance and isokinetic peak force. Results: Significant moderate to strong relationships were revealed between the SSASP distances and isokinetic peak forces for both limbs. The Bland–Altman analysis results demonstrated significantly (P < .002) greater limb symmetry indices for the SSASP (both medicine balls) than the isokinetic ratios, with biases ranging from −0.094 to −0.159. The limits of agreement results yielded intervals ranging from ±0.241 to ±0.340 and ±0.202 to ±0.221 from the biases. Conclusions: These results support the notion that the SSASP test reflects upper-extremity strength. The incongruency of the limb symmetry indices between the 2 tests is likely reflective of the differences in the movement patterns and coordination requirements of the 2 tests. [ABSTRACT FROM AUTHOR] more...

Chronic ankle instability (CAI) is a common pathology in handball. The role of the intrinsic musculature of the foot in these players in relation to proprioception and stability has not been stablished. The objective of this study was to compare the ultrasound morphology of the heel fat pad of the foot in professional handball players to CAI in healthy players and establish relationships between CAI and physical and psychological variables. The study has been a descriptive observational case–control study in which 20 professional handball male players over 18 years of age were divided into 8 cases (CAI) and 12 controls (healthy). An ultrasound evaluation, the thickness and/or cross-sectional area at rest and the contraction measurement of the Abductor Digiti Minimi, Abductor Hallucis, Flexor Digitorum Brevis and Quadratus Plantae muscles were analyzed. Moreover, the compressibility index of the heel fat pad and the activation of the abdominal wall musculature (ultrasound), the flexion strength of the hallux and lesser toes (dynamometry), the foot functionality (Bristol Foot Score (BFS) questionnaire) and the psychological variables (self-reported questionnaires) were measured. There were no significant differences between the activation capacity values of the foot muscles of healthy and CAI athletes. Significant differences were found between groups regarding the BFS score (p = 0.007), d = 1.404), and significant correlations were also found between hallux flexion strength and lesser toes flexion strength in the total sample. Although there were no differences between the two groups, the identification of the activation pattern of these muscles in handball athletes is essential to the improvement of performance and preventing injuries such as CAI. [ABSTRACT FROM AUTHOR] more...

Background: The level of quadriceps strength (QS) generated in the supine or seated position is not similar. For QS follow-up from intensive care unit (ICU) stay to recovery, getting comparable measures is essential. This study aimed to develop and validate new equations for estimating QS in a given position based on the measurement taken in another one. Methods and results: Isometric QS was measured using a handheld dynamometer and a standardized protocol in a supine and in a seated position. In a first cohort of 77 healthy adults, two QS conversion equations were developed using a multivariate model integrating independent parameters such as age, sex, body mass index (BMI) and baseline QS. These equations were tested in two cohorts for external validation, using the interclass correlation coefficient (ICC) and Bland–Altman graphical method. Only one was validated in the second cohort (62 different healthy adults): the ICC was 0.87 (95% CI 0.59–0.94) and the bias was − 0.49 N/Kg (limits of agreement: − 1.76–0.78 N/kg). However, this equation did not perform well in the third cohort (50 ICU survivors): the ICC was 0.60 (95% CI 0.24–0.78), and the bias was − 0.53 N/Kg (limits of agreement: − 1.01–2.07 N/kg). Conclusions: As no conversion equation has been validated in the present study, repeated QS measurements should be performed strictly in the same standardized and documented position. [ABSTRACT FROM AUTHOR] more...

Robotic-assisted rehabilitation is currently being applied to improve the effectiveness of human gait rehabilitation and recover the mobility and strength after a stroke or spinal cord injury; a robotic assistant can allow the active participation of the patient and the supervision of the collected data and decrease the labor required from therapists during the patient's training exercises. The goal of gait rehabilitation with robotic-based assistance is to restore motor function by using diverse control strategies, taking account of the physical interaction with the lower limbs of the patient. Over the last few years, researchers have extracted useful information from the patient's biological signals that can effectively reflect movement intention and muscle activation. One way to evaluate progress in rehabilitation is through isokinetic prototype tests that describe the dynamic characteristics of an isokinetic leg extension device for rehabilitation and control action. These tests use an isokinetic system to assess muscle strength and performance in a patient during isometric or isokinetic contraction. An experimental prototype shown in the following work allows the device's performance to be evaluated in a controlled environment before the patient's use. New features provide a control system that can be teleoperated for distributed structures, enabling the remote operation and management of the device. In order to achieve physical recovery from musculoskeletal injuries in the lower limbs and the reintegration of the affected subject into society as an independent and autonomous individual in their daily activities, a control model that introduces a medical isokinetic rehabilitation protocol is presented, in which the element that carries out such protocol consists of a magnetic particle brake whose control action is strongly influenced by the dynamics of the system when in contact with the end user—specifically, the patient's legs in the stretch from the knee to the ankle. The results of these tests are valuable for health professionals seeking to measure their patient's progress during the rehabilitation process and determine when it is safe and appropriate to advance in their treatment. [ABSTRACT FROM AUTHOR] more...

The process of design, build and eventual commissioning of the towing tank on the Boldrewood Innovation Campus is described. The design brief required a facility that would have a capability to test models at a commercial scale but that would be effective as teaching environment for the next generation of Naval Architects as well as providing a flexible space for future fundamental research. Each of these provided their own challenges but the eventual solution of a 138 m long, 3.5 m deep, 6 m wide facility has more than met the initial aspirations. Equipped with 12 independent 0.5 m wavemaking flaps at the West end, a passive beach at the East end, a deployable side beach along the South wall for post run wave absorption and a monocoque Aluminium alloy carriage, the Boldrewood towing tank has now been successfully operating for more than a year. The carriage position and speed are controlled by a twin winch arrangement using a laser positioning system and low embodied energy composite cables. The carriage can reach a maximum speed of 10 m/s with controllable acceleration rates and can have up to four constant speed phases per run. Initial commissioning results and comparisons with benchmark data for the KCS hull confirm the accuracy and repeatability of the facility. In particular, the position and speed of the carriage are known to a high level of precision. To date research and consultancy work has spanned the performance of high speed vessels, uncrewed underwater and surface vessels, wave energy and tidal current systems, floating platforms for wind turbines, performance sport work for sailing, kayaking, rowing and swimming, open water propeller tests as well as conventional displacement vessel testing for self-propulsion and resistance. All ship science and maritime engineering students use the facility as part of their taught modules in every year of their programme as well as for individual, MSc and group projects as appropriate. It has also made a strong impact on the many thousands of visitors a year to the campus for science and engineering open days. [ABSTRACT FROM AUTHOR] more...

Abstract Background Handgrip strength (HGS) is a simple, quick, inexpensive, and highly reliable method for the assessment of muscle strength in clinical practice and epidemiological studies. This study aimed at describing the HGS values by age group and sex in Brazilians aged 50 years and over, determining age group- and sex-specific cutoff points for muscle weakness, and investigating sociodemographic and anthropometric variables associated with muscle weakness for each sex. Methods Data from the second wave of the Brazilian Longitudinal Study of Aging (ELSI-Brazil) were analyzed. HGS was measured in the dominant hand using a hydraulic hand dynamometer. Fractional polynomial regression models were fitted to estimate the percentiles (P5, P10, P20, P25, P50, P75, P90, and P95) of HGS by age group and sex. The P20 of the maximum HGS by age group and sex was used to define muscle weakness. Associations between sociodemographic (racial self-classification, place of residence, schooling, and monthly household income per capita in tertiles) and anthropometric variables (body mass index and waist circumference) and muscle weakness, by sex, were evaluated using logistic regression. Results The analytical sample included 7905 participants (63.1 ± 9.1 years; 60% women). HGS reduced with increasing age in both sexes. Men presented higher HGS than women in all age groups. The cutoff points for muscle weakness ranged from 28 to 15 kg for men and from 17 to 9 kg for women. In the adjusted analyses, low schooling (0–4 years) was positively associated with muscle weakness in both sexes (in men, odds ratio (OR) 2.45, 95% confidence interval (CI) 1.46–4.12; in women, OR 1.90, 95%CI 1.18–3.06). Low and middle monthly household income per capita also had a positive association with muscle weakness among women (OR 1.78, 95%CI 1.37–2.32; OR 1.32, 95%CI 1.01–1.73, respectively). Overweight had a negative association with muscle weakness among men (OR 0.66, 95%CI 0.52–0.83), and obesity was inversely associated with muscle weakness in both sexes (in men, OR 0.49, 95%CI 0.31–0.78; in women, OR 0.69, 95%CI 0.52–0.92). Conclusions This study provides HGS values and cutoff points for muscle weakness by age group and sex from a nationally representative sample of older Brazilian adults. The variables associated with muscle weakness slightly differed between men and women. HGS values and cutoff points generated can be used as benchmarks in clinical settings and foster future epidemiological research. more...

The main aims of this study were to compare the magnitude of inter-limb asymmetry (ILA) and the relation with self-reported knee function between maximal and explosive knee extensor strength outcomes in professional soccer players. Forty-six male soccer players completed different maximal isokinetic and isometric contractions of the knee extensors for the assessment of maximal strength (peak torque and maximal voluntary contraction (MVC) torque) and explosive strength (early, intermediate, late, and peak rate of torque development (RTD)). Self-reported knee function was assessed with the International Knee Documentation Committee (IKDC) and Lysholm knee scoring scales. Peak torque and MVC torque showed comparable ILAs (8-9%), both being significantly lower than all RTD ILAs (16% on average; p < 0.001). ILAs for early RTD (21%) and peak RTD (19%) were significantly higher than all the other variables (p < 0.05). Only early and intermediate RTD were significantly correlated – though weakly – with both IKDC (rho = 0.32 for both) and Lysholm (rho = 0.36 and 0.30, respectively) scores. We conclude that explosive knee extensor strength – early RTD in particular – exhibited larger ILAs and better relations with self-reported knee function than peak torque and MVC torque in professional soccer players. These results confirm the validity and functional relevance of early RTD and the need for its inclusion in routine performance testing for soccer players. Highlights Professional soccer players exhibited larger inter-limb deficits in knee extension strength for explosive actions than for the widely-used isokinetic test. Self-reported knee function was significantly correlated with explosive strength of the knee extensor muscles but not with maximal strength. The first 50 ms of an explosive knee extension seem to be crucial for self-perceived sport performance and possibly for injury prevention. [ABSTRACT FROM AUTHOR] more...

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Context: Despite increasing use of reference values in isokinetic measurements and increasing importance, there is no systematic review of the reference values for lower and upper limb isokinetic muscle strength. Objective: A systematic review to analyze studies on the reference values and protocols for the measurement for upper and lower limb isokinetic muscle strength in an untrained and noninjured healthy population. Data Sources: MEDLINE, Scopus, Scielo, and CINAHL (from the earliest date available to June 2020). Study Selection: Studies that measured a set of reference values for isokinetic muscle strength. Study Design: Systematic review. Level of Evidence: Level 3. Data Extraction: Two reviewers selected studies independently. Data related to participants characteristics, outcomes of interest, isokinetic parameters, reference values for isokinetic muscle strength, and quality of evidence assessment were systematically reviewed independently by 2 authors. Results: A total of 31 studies met the study criteria. The included studies were used to synthesize the isokinetic muscle strength data according to age-group and sex. We extracted 1845 normative data related to isokinetic strength. Of these, 1181 items referred to lower limbs and 664 items to upper limbs. Conclusion: In general, agonist muscle groups are stronger than antagonist muscles, and the men tend to obtain higher strength values than women. The angular velocity varied from 10 to 300 deg/s. The reference values identified can be useful for professionals to obtain during the isokinetic evaluation of the diagnostic parameters of muscle deficiency. [ABSTRACT FROM AUTHOR] more...

Background: The isokinetic dynamometry is considered a gold standard in muscle strength testing. The reliability of lower limb isokinetic strength measurements has not been thoroughly evaluated. Objective: To examine the test−retest reliability of isokinetic ankle plantar and dorsiflexion, ankle inversion and eversion, knee extension and flexion and hip abduction and adduction strength in physically active adults using Biodex System 4 Pro. Methods: Peak torques (PTs) and average peak torques (APTs) of the dominant and nondominant lower limbs were tested twice in 19 physically active adults 7 to 14 days apart. Results: The intraclass correlation coefficients (ICC) values varied from excellent to moderate and coefficient of variation of typical error (CVTE) values were 6.6–19.5%. Change in the mean expressed as a percent varied from −3.1% to 9.6%. There was no difference in the reliability between PT and APT values. Dominant lower limb was more reliable in every case if there was difference between limbs. Conclusion: Test−retest reliability of isokinetic ankle, knee and hip strength in physically active adults using Biodex System 4 is mostly good or excellent. However, the observed range of the random variation has to be noted when using it in scientific follow-up studies or evaluation of patient progress in clinical settings. [ABSTRACT FROM AUTHOR] more...

Isometric strength and endurance performance of cervical flexor and extensor muscles were compared in women with (n = 30) and without (n = 30) idiopathic neck pain at the craniocervical and cervicothoracic axes. Strength and endurance time (time to task failure in seconds) at 50% maximal voluntary contraction were recorded in 4 directions (craniocervical flexion/extension and cervicothoracic flexion/extension) and 6 strength and endurance ratios were calculated. Participants in both groups were matched for body mass index. The idiopathic neck pain group demonstrated significantly less strength for the cervicothoracic flexors and extensors (1.58–4.7 N·m [12.4%–17.9%] less, P <.04) and significantly less endurance time for the cervicothoracic and craniocervical flexors (10.77–10.9 s [23.3%–27.5%] less, P <.03). The cervicothoracic extension to craniocervical flexion strength ratio was also lower in the idiopathic neck pain group (P =.01); however, no other strength or endurance ratio was significantly different between groups. This exploratory study suggests assessing specific performance parameters accounting for regional muscular differences in the upper and lower neck is potentially informative to understanding impairments in neck pain conditions, particularly as impairments may not be uniform across muscle groups. [ABSTRACT FROM AUTHOR] more...

Abstract Background Isokinetic dynamometry (IKD) is considered as the gold standard method of eccentric hamstring strength measurement, but other devices are more portable, cost-effective, provide real-time data and are thus better suited to the mass testing required in sport. This review aims to synthesise the evidence related to the reliability of and agreement between devices that measure eccentric hamstring strength and isokinetic dynamometers in adults. Methods The MEDLINE, EMBASE, PubMed, CINAHL and Sport Discus databases, alongside a search of grey and pre-print literature (from inception to 2021), are used. Forward and backward snowballing will also be used. Studies will be included if the reliability and/or agreement between devices used to quantify eccentric hamstring strength in healthy, recreationally active or amateur/elite sportspeople has been investigated. Studies will be excluded if (1) participants were injured or unwell at the time of testing and (2) concentric strength measurements or if non-hamstring muscle groups were investigated. The COnsenus-based Standards for the selection of health Measurement INstruments (COSMIN) tool will be used to assess the quality of reporting of included studies. If possible, data will be pooled and a meta-analysis and/or meta-regression may be performed if appropriate. We will aim to conduct a narrative synthesis using an adapted Grading of Recommendation, Assessment, Development and Evaluation (GRADE). Discussion This systematic review will aim to analyse the reliability of devices that measure eccentric hamstring strength, and the agreement of these devices with isokinetic dynamometers when used in an adult population. It is anticipated that the results of this review could be used to inform clinicians regarding suitable devices that can be employed to monitor eccentric hamstring strength in clinical practice. No ethics approval is required. It is anticipated that this review will be submitted to a leading peer-reviewed journal in this field for publication consideration. Systematic review registration www.researchregistry.com (reviewregistry1070) more...

Objective: To assess the change in relation of the peak quadriceps electromyographic signal to the peak torque produced during a train of 5 isokinetic knee extensions (from 90 degrees below horizontal at a constant speed of 60 degrees/s) at baseline, and at 4 and 8 weeks of pulmonary rehabilitation. Design: In this prospective observational study, isokinetic contractions were recorded during the extensions from the knee bent at 90 degrees to the horizontal plane against graded resistance. Peak quadriceps torque signal (Tq) and peak electromyographic signal (Eq) were recorded by dynamometry and surface electrodes placed at designated locations over the muscle group, respectively. Setting: Physical therapy department in a tertiary care medical center. Participants: Eighteen patients (9 restrictive lung disease, 6 chronic airflow limitation, 3 non-ILD restrictive; N=18) were compared with 11 healthy control subjects. Interventions: Patients underwent an 8-week pulmonary rehabilitation program. Main Outcome Measures: Comparisons of Tq, Eq, and Tq/Eq ratio among patients and controls were by analysis of variance. Associations between physiological variables were determined by multivariable Pearson's correlation. Results: Compared with patients, controls exhibited a 22% higher baseline mean peak Eq (P more...

Scientific opinions about the importance of dolphin upward leg movements for swimming performance are still divided. Research on the efficiency of propulsion, similarly generated by a relatively larger the monofin surface, showed that quality of the upward movement phase is a measure of swimming performance. Therefore, the forces generated as a result of upward and downward kicks in butterfly swimming were analysed. The ability of the swimmers to kinaesthetically control of the upward dolphin kicking was also researched. Ten international level butterfly swimmers (mean 18,2±1,4 years) took part in the research. They performed three trials on 25m distance, at maximum speed using the monofin device (The plate of standard monofin was removed and two strain gauges were affixed in the middle, between the toe). They randomly swam: 1) butterfly stroke (BS), 2) dolphin-kicking only (LK) and 3) swam being focused on activation of upward-kicking (AUK). Time dependent signals of the force sagging the fin in reaction to the water resistance were registered. The impulses of force sagging the fin in each stroke were lower in upbeat than in downbeat. The lowest difference was in AUK trial. First, Wilks's test and then Duncan's post hoc tests for each of the trial showed (at p≤0,05) that: downward impulses for LK was significantly higher than for BS. Upward impulses did not differ between the trials. Downward times for AUK, the same as total trial times, was significantly longer than for BS and for LK Upward times for AUK was significantly longer than for BS. The results demonstrated, that butterfly arms action leads to intensification of both kicking phases. The swimmers were well skilled for kinaesthetic controlling of the dolphin upbeat. They did not obtain the equal proportion between propulsion effect of both kicking phases, but it has been suggested, that this level of skill mastering is out of the human motor abilities. Opportunities for conscious controlling of the efficiency of the upward movement are seen in the modification of the time structure of this phase. These results could be used for improving the leg-kicking performance in butterfly swimming, as well as after stars and turns. [ABSTRACT FROM AUTHOR] more...

Aims: To discuss the advantages and limitation of the different pelvic floor muscle (PFM) dynamometers available, both in research and industry, and to present the extent of variation between them in terms of structure, functioning, psychometric properties, and assessment procedures. Methods: We identified relevant studies from four databases (MEDLINE, Compendex, Web of Science, and Derwent Innovations Index) up to December 2020 using terms related to dynamometry and PFM. In addition, we conducted a hand search of the bibliographies of all relevant reports. Peer‐reviewed papers, conference proceedings, patents and user's manuals for commercial dynamometers were included and assessed by two independent reviewers. Results: One hundred and one records were included and 23 PFM dynamometers from 15 research groups were identified. From these, 20 were considered as clinical dynamometers (meant for research settings) and three as personal dynamometers (developed by the industry). Overall, significant heterogeneity was found in their structure and functioning, which limits development of normative data for PFM force in women. Further research is needed to assess the psychometric properties of PFM dynamometers and to standardize assessment procedures. Conclusion: This review points up to the heterogeneity of existing dynamometers and methods of assessing PFM function. It highlights the need to better document their design and assessment protocol methods. Additionally, this review recommends standards for new dynamometers to allow the establishment of normalized data. [ABSTRACT FROM AUTHOR] more...

Featured Application: Evaluation of stabilisation times and landing strength requirements in high-level female netball players. Netball is a multidirectional sport afflicted by a relatively high proportion of lower-extremity injuries. The purpose of this study was to evaluate the relationships between multidirectional landing stabilisation times, unilateral landing kinetics, and isokinetic knee joint torques in elite female netball players. A total of 15 players volunteered for the study (age: 20.80 ± 1.42 years; height: 1.75 ± 0.06 m; body mass: 71.69 ± 13.58 kg). All players completed a minimum of 25 multidirectional, unilateral landing tasks, as well as isokinetic dynamometry, to evaluate both concentric and eccentric knee flexion and extension torques. Players showed rapid stabilisation times upon landing (2.02 ± 0.69 s) coupled with moderately high landing forces (4.06 ± 0.82 BWs) and comparatively low isokinetic knee extensor (2.01 ± 0.49 N·m·kg−1) and flexor (1.33 ± 0.30 N·m·kg−1) strength. Moderate positive ( r ¯ = 0.61) and negative ( r ¯ = −0.63) correlations were observed between peak isokinetic knee joint strength and the force–time waveform during the early and late weight-acceptance phases of multidirectional jump landings prior to stabilisation. Multidirectional landing kinetics can potentially provide valuable insights related to TTS and possible associations with isolated knee joint musculature during the weight-acceptance phase of jump landings. [ABSTRACT FROM AUTHOR] more...