Isometric Test Research Articles

Development and assessment of test-retest reliability of a new field test to evaluate lower-limb muscle fatigability in young adults

We aimed to develop a new field test to evaluate lower-limb muscle fatigability in young adults. In Experiment–A, we developed and determined the ability of an intermittent isometric wall-squat test to induce progressive level of muscle fatigability, as detected by the kinetics of changes in squat-jump height (SJH) and sit-to-stand time (STST) computed using two smartphone applications for feasibility purposes. In Experiment–B, participants performed the same test on two different days for reliability assessment. Kinetics of changes in our fatigability indicators were registered at isotime, exhaustion, and Post2min. The minimal detectable change (MDC95) and the absolute (CVTE) and relative (ICC3-1) reliability coefficients were assessed. In Experiment–A, we reported a progressive decrease in performance for SJH and STST throughout the task, reaching at exhaustion mean changes of −22±11% and +31±13%. Individual data-analysis showed decrease in performance for SJH and STST greater than the MDC95 in 85% and 95% of participants. In Experiment–B, changes in our fatigability indicators demonstrated excellent inter-session reliability at isotime, exhaustion and Post2min for SJH (ICC3-1 > 0.97; CVTE < 7.5%) and STST (ICC3-1 > 0.92; CVTE < 3.3%). This test is feasible and reliable, making it very promising for evaluating muscle fatigability in applied (e.g. clinical) and laboratory settings.

Validación de test de flexión-relajación para definir un déficit lumbar con electrodos tetrapolares

Introduction and objectiveTo obtain a new cut-off point (CP) for a lumbar flexion-relaxation (RF) test established with tetrapolar (e.) electrodes, from values already defined with bipolar devices. Materials and methodsThe study sample consists of 47 patients in a situation of temporary disability due to low back pain (DL). They were evaluated by means of an isometric dynamometry test, a kinematic test and an assessment of the FR phenomenon.Two experiments with ROC curves are proposed. The first, with 47 patients who consecutively performed the RF test with both types of electrodes, using the cut-off point (CP) known for the e. bipolar (2.49μV). In the second, with the EMG data recorded with e. tetrapolar in 17 patients, a DeLong test was performed that compares the 2 ROC curves that were constructed on the one hand, by classifying the sample from dynamometry and kinematic tests, and on the other, by classifying them with the bipolar EMG values. ResultsA total of 34 patients adequately completed the evaluations of the first experiment and 17 patients the second. The first study shows a cut-off point of 1.2μV, with an AUC of 87.7%; Sensitivity 84.2% and Specificity 80%. The second shows a PC for e. bipolars of 1.21μV (AUC 87.5%) and for e. tetrapolar values of 1.43 (AUC 82.5%) with a DeLong test without significant differences between both curves (p>0.4065). ConclusionsThe validation methodology with ROC curves has made it possible to obtain a new PC for the RF test in a practical way, simply by simultaneously performing both tests on the same group of patients until a significant sample is obtained.

The Effect Of Automated Component Impaction On The Surgeon’s Ergonomics, Fatigue And Stress Levels In Total Hip Arthroplasty

Background Total Hip Arthroplasty (THA) surgery is physically and cognitively challenging. Sub-optimal posture during component impaction may influence surgeon’s ergonomics and fatigue. Methods Thirty THA procedures were executed for 3 days. Only during the first day, manual impaction (MI) was performed. Postural risk was evaluated with Rapid Upper Limb Assessment (RULA) and Rapid Entire Body Assessment (REBA) score. Three cognitive tasks (Simon, pattern comparison and pursuit rotor test) and five physical tests (isometric wall-sit, plank-to-fatigue, handgrip, supra-postural task, and shoulder endurance) assessed surgeon’s psycho-physiological load in the morning, midday, and afternoon. Surgeon’s cortisol concentration and sound level of the broaching process was also recorded. Results RULA and REBA scores were 1.7 to 3 times lower with automated impaction (AI). Physical exhaustion was lower with AI: isometric wall-sit test (10.6% vs. 22.9%), plank-to-fatigue (2.2% vs. 43.8%), supra-postural task (-0.7% vs. -7.7%), handgrip force production (dominant hand -6.7% vs. -12.7%; contralateral +4.7% vs. +7.7%), and in shoulder endurance (-15s vs. -56s). After AI, the cognitive performance showed faster response times and lower error rates for all cognitive tests compared to MI. The salivary cortisol level decreased during the AI-days by 51% in comparison to a 38% increase following the MI-day. Mean broaching time with AI was 7’3’’ compared to 6’20’’ with MI. The mean sound level with the AI-device was 64.3 dBA compared to 68.2 dBA with manual impaction. Conclusions Automated THA component impaction improved the surgeon’s ergonomics which resulted in reduced hormonal stress levels and lower physical and cognitive exhaustion.

Skin Bioimpedance Analysis to Determine Cellular Integrity by Phase Angle in Women with Fibromyalgia: A Cross-Sectional Study.

Oxidative stress has been proposed as a significant part of the pathogenesis of fibromyalgia, and the phase angle in bioelectrical impedance analysis has been explored as a potential technique to screen oxidative abnormalities. This study recruited 35 women with fibromyalgia and 35 healthy women, who underwent bioelectrical impedance analysis and maximum isometric handgrip strength tests. Women with fibromyalgia showed lower bilateral handgrip strength (right hand: 16.39 ± 5.87 vs. 27.53 ± 4.09, p < 0.001; left hand: 16.31 ± 5.51 vs. 27.61 ± 4.14, p < 0.001), as well as higher body fat mass (27.14 ± 10.21 vs. 19.94 ± 7.25, p = 0.002), body fat percentage (37.80 ± 8.32 vs. 30.63 ± 7.77, p < 0.001), and visceral fat area (136.76 ± 55.31 vs. 91.65 ± 42.04, p < 0.01) compared with healthy women. There was no statistically significant difference in muscle mass between groups, but women with fibromyalgia showed lower phase angles in all body regions when compared with healthy control women (right arm: 4.42 ± 0.51 vs. 4.97 ± 0.48, p < 0.01; left arm: 4.23 ± 0.48 vs. 4.78 ± 0.50, p < 0.001; trunk: 5.62 ± 0.77 vs. 6.78 ± 0.84, p < 0.001; right leg: 5.28 ± 0.56 vs. 5.81 ± 0.60, p < 0.001; left leg: 5.07 ± 0.51 vs. 5.69 ± 0.58, p < 0.001; whole body: 4.81 ± 0.47 vs. 5.39 ± 0.49, p < 0.001). Moreover, whole-body phase-angle reduction was only predicted by the presence of fibromyalgia (R2 = 0.264; β = 0.639; F(1,68) = 24.411; p < 0.001). Our study revealed significantly lower phase angle values, lower handgrip strength, and higher fat levels in women with fibromyalgia compared to healthy controls, which are data of clinical relevance when dealing with such patients.

A Neuromuscular Training Program Performed on Foam is Accompanied by Improved Balance and Jump Height in Recreational Runners

Purpose: To assess balance, plyometric performance, and strength of recreational runners completing a neuromuscular training (NMT) program on a novel foam surface. Methods: After baseline testing, participants (n=14) completed 22-minute exercise sessions on foam twice weekly for eight weeks, and a post-training testing battery. Testing included lower quarter Y-balance test (LQYBT), dynamic leap and balance test (DLBT), squat jump and countermovement jump tests, and isometric strength testing of the foot and ankle via handheld dynamometry (HHD). Participants were asked to maintain their normal running routines throughout the study period and report any training missed due to injury. Results: Participants demonstrated significant (pConclusion: This study supports the use of progressive NMT on foam as a feasible intervention for recreational runners as all participants maintained typical running routines and reported no injuries. While further research is needed to directly inform possible effects of NMT on foam on injury risk and running performance, the improvements in single leg dynamic balance, lower body plyometric performance, and some indices of lower extremity strength in the present study suggest the efficacy of NMT performed on foam.

Exercise-Induced Transient Oxidative Stress Is Mitigated in Down Syndrome: Insights About Redox Balance and Muscle Strength.

Reis, AL, Deus, LA, Neves, RVP, Corrêa, HL Reis, TL, Aguiar, LS Honorato, FS, Barbosa, JMS, Araújo, TB, Palmeira, TRC, Simões, HG, Prestes, J, Sousa, CV, Ide, BN, and Rosa, TdS. Exercise-induced transient oxidative stress is mitigated in Down syndrome: insights about redox balance and muscle strength. J Strength Cond Res 38(3): e125-e34, 2024-This study aimed to evaluate the acute effects of a session of resistance exercise (RE) performed with elastic tubes on the redox balance and inflammatory profile in individuals with Down syndrome (DS). Subjects ( n = 23) were allocated into 2 groups: individuals with DS (DS; n = 11) and individuals without DS (WDS; n = 12), who performed an acute RE session. Diagnostic assessment included medical history, anthropometric measures (body height, body mass, body mass index, and body composition assessment), biological collections, muscle strength assessments (handgrip and maximal voluntary isometric contraction tests), and exercises. The redox balance and inflammatory profile were assessed in urine and saliva samples before and after an acute RE session. There were no differences between WDS and DS groups for body composition ( p > 0.05). The DS group presented higher values pre and post an acute RE session with elastic tubes for oxidative and proinflammatory markers compared with WDS ( p < 0.05). Uric acid values increased from pre-acute RE session to post-acute RE session for WDS ( p < 0.0001). No differences were identified within groups for the delta analysis ( p > 0.05). Inverse correlations were found between total force and F2-isoprostane, 8OHdG, uric acid, allantoin, IL-6, TNF-α, and the TNF-α:IL-10 ratio. A positive correlation was found between IL-10 and total force. The DS group presented increased peak force in the knee extension and elbow flexion exercises (∼25 and 12%, respectively) but decreases in handgrip strength of ∼7%. The WDS group showed higher peak force values for knee extension, elbow flexion, and handgrip (∼16, 10, and 14%, respectively). The DS group had lower transient elevation of oxidative stress after an acute RE session compared with WDS. Oxidative stress and inflammation responses of DS to an acute RE session with elastic tubes may be insufficient to induce health adaptations for the same relative load compared with WDS.

The reliability and suitability of strength assessments in frail and pre-frail older adults: recommendations for strength testing in older populations

BackgroundLifelong strength is fundamental to physical function, health, and quality of life. Reliable appropriate strength assessment measures for older adults play an important role in effective evaluation of baseline ability and exercise prescription to counter disease and disuse. This study aimed to investigate the within-session reliability of maximal isometric knee extension and flexion, hip abduction and adduction, and handgrip strength measures in frail and pre-frail older adults.MethodThe study was conducted at a residential care home in Birmingham, UK. All care home residents aged ≥ 65 years; pre-frail or frail according to the Fried Frailty phenotype criteria; able to speak and read English; not currently involved in any other clinical trial; without severe sensory impairments; and with a predicted life expectancy greater than the trial length were eligible. Maximal isometric lower limb testing was performed using specialised resistance training equipment and a portable measurement device, and grip strength was assessed using a portable dynamometer. All eligible participants attended a single testing session and performed three trials per measure. Peak force measures were obtained for analysis. Within-session reliability for each measure was calculated from repeated-measures analysis of variance, intraclass correlation coefficients (ICC), and coefficients of variation (CV) with 95% confidence intervals.ResultsEleven frail and eleven pre-frail older adults participated in the study. Within-session absolute and relative measures were found to be reliable with the highest overall repeatability indicated between trial 2 and trial 3 for knee extension, hip abduction, and handgrip (CV ≤ 4.65%, ICC ≥ 0.96) with variation evident across all measures, except knee extension, from trial 1 to 2.ConclusionsOverall, maximal isometric strength in frail and pre-frail older adults with no previous testing experience can be measured with good to high reliability within their first testing session. An initial two familiarisation trials followed by two measurement trials is recommended to achieve the highest level of overall repeatability.Trial registrationThe trial was registered with ClinicalTrials.gov: NCT03141879 on 05/05/2017.

Contraction intensity affects NIRS-derived skeletal muscle oxidative capacity but not its relationships to mitochondrial protein content or aerobic fitness.

To further refine the near-infrared spectroscopy (NIRS)-derived measure of skeletal muscle oxidative capacity in humans, we sought to determine whether the exercise stimulus intensity affected the τ value and/or influenced the magnitude of correlations with in vitro measures of mitochondrial content and in vivo indices of exercise performance. Males (n = 12) and females (n = 12), matched for maximal aerobic fitness per fat-free mass, completed NIRS-derived skeletal muscle oxidative capacity tests for the vastus lateralis following repeated contractions at 40% (τ40) and 100% (τ100) of maximum voluntary contraction, underwent a skeletal muscle biopsy of the same muscle, and performed multiple intermittent isometric knee extension tests to task failure to establish critical torque (CT). The value of τ100 (34.4 ± 7.0 s) was greater than τ40 (24.2 ± 6.9 s, P < 0.001), but the values were correlated (r = 0.688; P < 0.001). The values of τ40 (r = -0.692, P < 0.001) and τ100 (r = -0.488, P = 0.016) correlated with myosin heavy chain I percentage and several markers of mitochondrial content, including COX II protein content in whole muscle (τ40: r = -0.547, P = 0.006; τ100: r = -0.466, P = 0.022), type I pooled fibers (τ40: r = -0.547, P = 0.006; τ100: r = -0.547, P = 0.006), and type II pooled fibers (τ40: r = -0.516, P = 0.009; τ100: r = -0.635, P = 0.001). The value of τ40 (r = -0.702, P < 0.001), but not τ100 (r = -0.378, P = 0.083) correlated with critical torque (CT); however, neither value correlated with W' (τ40: r = 0.071, P = 0.753; τ100: r = 0.054, P = 0.812). Overall, the NIRS method of assessing skeletal muscle oxidative capacity is sensitive to the intensity of skeletal muscle contraction but maintains relationships to whole body fitness, isolated limb critical intensity, and mitochondrial content regardless of intensity.NEW & NOTEWORTHY Skeletal muscle oxidative capacity measured using near-infrared spectroscopy (NIRS) was lower following high-intensity compared with low-intensity isometric knee extension contractions. At both intensities, skeletal muscle oxidative capacity was correlated with protein markers of mitochondrial content (in whole muscle and pooled type I and type II muscle fibers) and critical torque. These findings highlight the importance of standardizing contraction intensity while using the NIRS method with isometric contractions and further demonstrate its validity.

Which Tests Predict 6-Month Isokinetic Quadriceps Strength After ACL Reconstruction? An Examination of Isometric Quadriceps Strength and Functional Tests at 3 Months.

Restoration of quadriceps strength after anterior ligament reconstruction (ACLR) is a persistent challenge for patients and clinicians. Inadequate recovery of quadriceps strength has been linked to increase risk of re-injury. Developing methods of early identification of strength deficits is essential to allow clinicians to provide more individualized interventions early in the rehabilitation process. To determine whether 3-month isometric quadriceps strength, the Y-Balance Test (YBT), and the anterior step-down test are predictive of isokinetic quadriceps strength at six months in adolescents after ACLR. Retrospective cohort. Thirty-six adolescent patients with primary ACLR (58% female, 36% with concomitant meniscal repair, age: 15.7 ± 1.6 years). At three months post-operative, isometric quadriceps strength via isokinetic dynamometer, YBT-Lower Quarter, and anterior step-down tests were completed. At six months post-operative, an isokinetic knee strength assessment was completed. Regression analysis was used to evaluate the predictive relationship between 3-month isometric tests and 6-month isokinetic knee extension tests. Three-month post operative isometric quadriceps peak torque predicted isokinetic quadriceps peak torque at 6 months, F(1,34) = 19.61, p <0.001. Three-month isometric quadriceps peak torque accounted for 36.6% of the variance in normalized isokinetic quadriceps peak torque at 6 months with adjusted R2 = 34.7%. Including YBT anterior reach (β = 0.157, p = 0.318) in regression added 1.9% of variance when predicting 6-month isokinetic quadriceps peak torque, F (2,33) = 10.32, p <0.001, R2 = 0.385, ΔR2 = 0.019. At three months post-ACLR, isometric strength testing appears more optimal than other functional tests in predicting isokinetic quadriceps peak torque in later stages of rehabilitation for adolescents. Clinicians should use tests at three months that measure quadriceps strength if aiming to predict isokinetic quadriceps peak torque at six months post-ACLR, rather than using functional tests such as the YBT-LQ or anterior step-down. Level 3.

Handedness, Bilateral, and Interdigit Strength Asymmetries in Male Climbers.

To determine whether there are bilateral and interdigit differences in the maximal force production of experienced climbers and whether these differences are mediated by ability level or preferred style of climbing. Thirty-six male climbers (age 30 [9.4]y) took part in a single-session trial to test their maximal force production on both hands. The tests included a one-arm maximal isometric finger flexor strength test (MIFS) and a one-arm individual MIFS. Bilateral differences were analyzed by strongest hand (defined as the hand that produced the highest MIFS value) and dominance (defined as the writing hand). A pairwise t test found thatMIFS was significantly greater for the strongest hand (mean difference = 4.1%, 95%CI, -0.052 to 0.029, P < .001), with handedness explaining 89% of the variation. A 2-way mixed-model analysis of variance determined that there were no interactions between preferred style (bouldering or sport climbing) and MIFS or betweenability level (advanced or elite) and MIFS. Climbers have significant finger flexor strength bilateral asymmetries between their strongest and weakest hand. Moreover, when dominance is controlled, this difference in strength is present, with the dominant hand producing more force. Neither preferred style of climbing nor the ability level of the climbers could explain these asymmetries. As such, practitioners should consider regularly monitoring unilateral strength, aiming to minimize the likelihood of large bilateral asymmetry occurring.

Physical and psychological effects of outdoor fitness equipment training on middle-aged and older adults: study protocol of a randomised controlled trial

This project will investigate the effectiveness of an 8-week outdoor fitness equipment (OFE) programme on health parameters in healthy community-dwelling middle and older adults, corresponding to the present paper to...

Reliability of a handball specific strength test battery and the association with sprint and throwing performance in young handball players.

A greater motivation for coaches to be more involved in assessment could be the development of specific strength tests closer to specific handball tasks. Therefore, the aims were to determine the reliability of a handball specific strength test battery in young handball players using a functional electromechanical dynamometer (FEMD) and to evaluate the association between the strength test battery and performance measurements. Thirty-two young handball players (25% males and 75% females) performed a repeated-measurement design over four weeks. The players conducted one session per week, with each measurement consisting of two isometric tests to obtain isometric peak force, and four incremental tests. Moreover, performance handball tests (sprint and throwing velocity [TV]) were recorded. The reliability of the whole handball specific strength tests was very high for the peak and mean strength (ICC=0.70-0.85; CV=8.49-13.99; SEM=0.44-0.67 kg). The step forward had a moderate association with 5 to 10 meters' time. The highest correlation between TV<inf>mean</inf> was found with the peak strength of standing lift and between TV<inf>peak</inf> with peak strength of unilateral throw. The sprint total time could be explained by Body Mass Index and peak strength of the standing lift in the 40% and the TV<inf>peak</inf> could be explained by arm span and mean strength of the standing lift in the 68%. The high reliability for all exercises and the significant correlation with handball performance (sprint time and TV) allow us to include these tests in handball team evaluation and training.

The Kneeling Isometric Plantar Flexor Test: Preliminary Reliability and Feasibility in Professional Youth Football.

Calf injuries are common in professional football; thus, the establishment of reliable and time-efficient methods of measuring the peak force capabilities of the plantar flexors with equipment that is accessible to football practitioners is valuable. In this study, we determined the preliminary reliability and feasibility of a new test, termed the kneeling isometric plantar flexion test (KIPFT), for footballers. Twenty-one male youth footballers (age = 17.8 ± 1.1 years, height = 182 ± 5 cm, weight = 77.6 ± 5.9 kg) from English League One football clubs completed three trials of the KIPFT on a wireless force plate at the end (2022-2023) and start (2023-2024) of the season. The within-session reliability of the peak force (relative to body weight) was good-excellent for both limbs and both occasions. On average, performance of the KIPFT took just over 1 min per limb and ~2 min to set up. The peak force values were larger for the non-dominant limbs only at the start versus the end of the season, but there were no between-limb differences. From these results, it was determined that (1) the KIPFT is feasible, (2) a minimum of 32 footballers would be required to establish its between-session reliability with ≥80% statistical power and (3) large-cohort normative data for the KIPFT may be best collected at the start of the football season.

Effect of Lactobacillus plantarum PS128 on neuromuscular efficiency after a half-marathon

Introduction:Lactobacillus plantarum PS128 (PS128) could be considered an antioxidant supplement to reduce muscle fatigue and improve exercise capacity recovery after vigorous exercise.Purpose: The purpose of this study is to investigate the effect of PS128 on muscle fatigue and electromyography (EMG) activity after a half-marathon (HM).Methods: The experimental design used a repeated-measures design with a double-blind approach. The participants either took two capsules of PS128 for 4 weeks as the PS128 group (PSG, n = 8) or took two capsules of a placebo for 4 weeks as the placebo group (PLG, n = 8) to ensure counterbalancing. The time points of the maximal voluntary isometric contraction (MVIC) and EMG activity test were set before probiotics were taken (baseline), 48 h before HM (Pre), and immediately at 0 h, 3 h, 24 h, 48 h, 72 h, and 96 h after HM.Results: EMG activity included median power frequency (MDF), integrated EMG (iEMG), and neuromuscular efficiency (peak torque/iEMG). The MVICs of knee extensors, analyzed by using an isokinetic dynamometer, showed a decrease from the Pre to 0 h (p = 0.0001), 3 h (p &amp;lt; 0.0001), 24 h (p &amp;lt; 0.0001), 48 h (p &amp;lt; 0.0001), 72 h (p = 0.0002), and 96 h (p = 0.0408) time points in the PLG. Sidak’s multiple comparisons tests showed that the PLG was significantly lower than the PSG at 0 h (p = 0.0173), 3 h (p &amp;lt; 0.0001), 24 h (p &amp;lt; 0.0001), 48 h (p &amp;lt; 0.0001), 72 h (p &amp;lt; 0.0001), and 96 h (p = 0.0004) time points. The MDF of vastus medialis oblique (VMO) in the PLG was significantly decreased 24 h after HM and significantly lower than that in the PSG at all times points after HM. The iEMG of VMO in the PLG was significantly decreased 48 h after HM and significantly lower than that in the PSG at 0 h, 3 h, 24 h, 48 h, and 72 h after HM.Conclusion: The PS128 supplementation may prevent the decrease in MDF, iEMG, and peak torque after vigorous exercise. Recreational runners may consider implementing a probiotic supplementation regimen as a potential strategy to mitigate muscle fatigue following HM.

A Cadaveric Study of the Optimal Isometric Region on the Anterolateral Surface of the Knee in Anterolateral Ligament Reconstruction.

Isolated intra-articular anterior cruciate ligament (ACL) reconstruction is not capable of restoring instability in many cases leading some to recommend concomitant anterolateral ligament (ALL) reconstruction. The satisfactory fixation site and graft length change are crucial in ligament reconstruction to restore the ALL function and avoid some unwanted graft behavior. The purpose of this investigation is to determine the optimal isometric region on the anterolateral aspect of the knee for ALL reconstruction using a three-dimensional optical instrument and a suture similar to an intraoperative isometric test. Six freshly frozen cadaveric human knees were used in this study. Data regarding the anterolateral surface were obtained using an optical measurement system to create a three-dimensional model. Nine points were selected on the femur (F1-F9) and tibia (Ta-Ti) respectively. The three-dimensional length change between each pair of tibial and femoral points was measured during passive knee flexion from 0° to 90° in 15° increments. Subsequently, five femoral points (A-E) were selected from the lateral femur, located in different areas relative to the lateral femoral epicondyle, and three tibial reference points (T1-T3) were selected in the isometric test. The changes in the length between each pair of reference points were measured using sutures. The 95% confidence interval for the rate of length change was estimated using the mean and standard deviation of the maximum rate of length change at different flexion angles, and the data were expressed as the mean (95% confidence interval) and compared with the maximum acceptable rate of change (10%). The maximum acceptable change rate for ligament reconstruction is 10%, and the mean maximum rates and the 95% confidence interval (CI) of length change for the point combinations were calculated. Among all the combined points measured using the optical measurement system and the suture, the qualified point combination for reconstruction was F3 (8mm posterior and 8mm proximal to the lateral femoral epicondyle)-Tb (8mm proximal to the midpoint between the center of Gerdy's tubercle and the fibula head), A (posterior and proximal to the lateral femoral epicondyle)-T2 (10mm below the joint line)and A-T3 (15 mm below the joint line). The position of F3-Tb and A-T2 are close to each other. The most isometric area of the femur for ALL reconstruction was posterior and proximal to the lateral femoral epicondyle. We recommend that the initial location of the femoral point be set at 8 mm posterior and 8 mm proximal to the lateral femoral epicondyle and the tibial point at approximately 10 mm below the joint line, midway between Gerdy's tubercle and fibular head, and subsequently adjusted to the most satisfactory position according to the isometric test.

Reliability of a Trunk Flexion and Extensor Muscle Strength Test with Hand-Held and Isokinetic Dynamometers in Female Athletes.

An accurate trunk muscle strength assessment seems very important to design and individualize training and rehabilitation programs in clinical and sport settings. Hand-held dynamometers (HHDs) are interesting alternatives to isokinetic dynamometers for assessing trunk isometric muscle strength because they are inexpensive instruments and easy to use. This cross-sectional observational study aimed to examine the reliability of two novel sitting tests for assessing trunk flexion and extension isometric strength using an HHD and their relationship with two other novel isometric tests that use an isokinetic dynamometer. Twenty-four female amateur athletes (age: 24.5 ± 2.64 years; body height: 164.45 ± 6.33 cm; body mass: 63.17 ± 10.35 kg) participated in this study. A test-retest design was carried out one-week apart to examine the reliability. The relationship and the degree of agreement between the HHD and the isokinetic dynamometer measurements were analysed using Pearson correlation and Bland-Altman analysis, respectively. In general, the reliability of all isometric strength tests was good, with ICCs ranging from 0.65 to 0.87 and typical error < 15%. Pearson correlations were moderate, with values of r = 0.47 (R2 = 0.22) and r = 0.42 (R2 = 0.18) for flexion and extension strength, respectively. Bland-Altman plots showed no agreement between HHDs and isokinetic measurements. All trunk isometric tests using both, an isokinetic dynamometer and HHDs, provide reliable measurements for assessing trunk flexion and extension strength. According to the comparative analysis, both measurement types are different and cannot be used interchangeably. Health and sport professionals should choose the test that best suits the biomechanical characteristics required for functional goals or success in a given sport.

Can photobiomodulation improve quadriceps strength and endurance outcomes in asymptomatic adults? A double-blind randomized controlled trial

AimTo explore the effect of photobiomodulation on quadriceps strength and endurance torques in asymptomatic adults. MethodsTwenty-eight asymptomatic adults were randomized to one of two interventions: photobiomodulation (n = 14) or sham (n = 14). Quadriceps strength was evaluated by maximum voluntary isometric contraction test (60°) and endurance by an elastic resistance in multiple-set knee extension/flexion repetitions using a traction dynamometer. The outcomes were measured at three time points: pre-baseline; baseline and; final assessment. The photobiomodulation was applied to the quadriceps and triceps surae muscles of each participant's dominant lower limb, using a cluster with 1 infrared laser diode and 3 led amber of 170 mW for 240 s over four consecutive days. The sham group went through the same procedures, but the equipment was off, and patients and assessors were blinded to the intervention. Reliability and minimal detectable change of the measures were obtained from the pre-baseline and baseline time points. Differences between interventions were tested by an analysis of covariance. Results and discussionThere was no difference between photobiomodulation compared to sham in maximum isometric torque (mean difference (95% CI) = 0.008 (−0.29 to 0.31) and endurance torques (mean difference (95% CI) = 0.04 (−0.03 to 0.12). The mean difference was lower than the minimal detectable change for the maximum isometric torque (1.02 Nm.kg−1) and endurance torque (0.49 Nm.kg−1). ConclusionPhotobiomodulation does not improve quadriceps strength and endurance outcomes in asymptomatic adults.

A comparative study of the efficacy of instrument-assisted soft tissue mobilization and massage techniques in patients with patellofemoral joint pain.

The aim of this study was to compare the clinical efficacy of instrument-assisted soft tissue mobilization (IASTM) and manipulative therapy Tui-na techniques in the treatment of patients with patellofemoral joint pain syndrome, and to evaluate their impact on pain relief, functional improvement, and joint range of motion. In this study, 25 patients with patellofemoral pain syndrome were enrolled, comprising of an intervention group of 13 patients who received IASTM treatment and a control group of 12 patients who received Tui-na manipulation therapy. The treatment cycle lasted for 4 weeks, featuring two interventions per week. Before treatment, the visual analog pain scale (VAS) of the knee, Lysholm score of the knee, modified Thomas test (MTT), and maximum isometric strength of the extensor muscles of the lower limbs were measured and recorded for both groups. After the first and last treatments, the aforementioned indexes were reassessed, and the maximum isometric muscle strength of the lower extremity extensors was measured only after 4 weeks of treatment had been completed. There was no significant difference in the basic information of the two intervention groups (p > 0. 05). After the first treatment and 4 weeks of treatment, the Lysholm score in both groups significantly improved (p < 0. 05), indicating that both interventions can improve the function of patients' lower limbs. However, the Lysholm score in the IASTM group significantly increased compared with that of the massage group after 4 weeks of treatment, indicating that its improvement in functional performance is superior. Both groups showed significant improvement in knee joint pain after the first treatment and 4 weeks of treatment (p < 0. 05), with the IASTM group having a lower VAS score and better pain improvement after 4 weeks of treatment. The strength of the two intervention groups significantly increased after the maximum isometric muscle strength test of the lower limb extensor muscles before and after 4 weeks of treatment (p < 0. 05). After the MTT test, the extension angle, deviation angle, and hip abduction angle of the tested legs in the two intervention groups were significantly reduced (p < 0. 001), indicating an improvement in lower limb joint mobility. Instrument-assisted soft tissue mobilization treatment and Tui-na manipulation therapy significantly reduced pain, improved knee flexibility, and increased range of motion of the lower extremity in patients with PFPS. However, IASTM treatment significantly improved pain and function and sustained pain in the short to medium-term post-trial period. www.isrctn.com, ISRCTN88098928.

Isometric Shoulder Testing Using a Forcemeter Is a Reliable Method of Strength Evaluation.

Isometric strength testing using a digital dynamometer is reliable for muscle function evaluation. It allows us to objectify manual strength assessment measurement. We tested intra- and inter-observer reliability of a user-friendly efficient digital dynamometer-the Forcemeter-equipped with a computer program to monitor the measurements and to store the data. Abduction, forward flexion, and external and internal rotation of both shoulders were tested three times in 20 healthy volunteers with no record of shoulder trauma. Isometric contracture was recorded in newtons. The first and the third test were carried out by Examiner A (intra-rater reliability); the second test, by Examiner B (inter-rater reliability). Good reliability was shown for intra-class correlation coefficient (ICC) values which mean moderate to high correlations (r = 0.66-0.93) for both examiners. Moderate to high correlations (r = 0.72-0.91) were found for comparisons between the results obtained by Examiner A.

Handgrip echocardiography predicts clinical outcomes in patients with ischemic mitral regurgitation

Abstract Background Mitral regurgitation (MR) is frequent in patients with ischemic heart disease and carries a dismal prognosis. Previous studies already demonstrated the prognostic benefit of bicycle exercise testing in patients with ischemic MR. Thus, current guidelines emphasize the role of exercise testing in patients with valvular heart disease. Isometric handgrip exercise resembles an alternative exercise intervention, that can also be performed in frail, comorbid patients. Until now, there are no data on the prognostic impact of handgrip echocardiography in heart failure patients with ischemic MR. Purpose To assess the prognostic benefit of isometric handgrip testing in heart failure patients with ischemic MR. Methods We prospectively enrolled patients with ischemic cardiomyopathy (left ventricular ejection fraction &amp;lt;50%) and at least mild MR that underwent echocardiography at rest and during handgrip exercise between January 2019 and September 2021. Patients were followed-up for one year to assess clinical outcomes. The combined endpoint included all-cause mortality, heart failure hospitalisation, ventricular assist device implantation (VAD), heart transplantation and mitral valve (MV) surgery/intervention. Results We included 133 patients (mean age was 75±10 years, 21% were female). Seventy patients (53%) presented with mild MR, while 54 patients had moderate MR (41%), and 9 patients (7%) showed severe MR at rest. Twenty-five patients (20%) with non-severe MR at rest, developed severe MR during handgrip exercise. One-year follow-up (median 321 (162-427) days) was complete in 128 patients (96%). Seventy-one patients (56%) experienced an adverse event: 13 patients (10%) died, 33 patients (26%) were re-admitted to hospital due to heart failure symptoms, 30 patients (24%) underwent MV transcatheter edge-to-edge repair, six patients (5%) received MV surgery, one patient (1%) underwent VAD implantation, and another three patients (4%) underwent heart transplantation. According to MR severity at rest, there was no difference in outcomes in patients with mild, moderate and severe MR (p=0.189). As expected, patients with severe MR at rest more often tended to undergo mitral valve surgery/interventions compared to the other groups (p=0.064). However, patients with non-severe MR at rest and exercise-induced severe MR presented with adverse outcomes similar to patients with severe MR at rest (p=0.005). Furthermore, patients with severe MR at rest and patients with dynamic severe MR underwent mitral valve surgery/interventions more frequently than patients with non-severe MR (p&amp;lt;0.001). Conclusion(s) In heart failure patients with ischemic MR, isometric handgrip testing unmasks severe MR in approximately every fifth patient with non-severe MR at rest. These patients showed similar clinical outcomes as compared to patients with severe MR already at rest. Thus, handgrip exercise testing might be a useful tool to guide further therapeutic decision making.