Isometric Handgrip Research Articles

Effects of the intensity, duration and muscle mass factors of isometric exercise on acute local muscle hemodynamic responses and systematic blood pressure regulation.

Isometric exercise is a non-pharmacologic intervention to improve muscle hemodynamic responses and blood pressure in humans. However, the effects of intensity, duration, and muscle mass factors of isometric exercise on local muscle hemodynamic responses and systemic blood pressure regulation have not been studied. The purpose of this study was to assess whether various modes of isometric exercise could induce various levels of muscle hemodynamic responses that are related to the blood pressure changes. Near-infrared spectroscopy was used to assess muscle hemodynamic responses after 4 isometric exercise protocols in 20 healthy adults. One-way analysis of variance (ANOVA) with repeated measures was used to assess the effect of factors of isometric exercise on oxyhemoglobin, deoxy-hemoglobin, blood volume, and oxygenation. For oxygenation, the lowest mean was recorded for the unilateral isometric handgrip exercise at 30% of MVC for 2min (-0.317 ± 0.379μM) while the highest mean was observed for the isometric wall squat (1.496 ± 0.498μM, P < 0.05). Additionally, both the bilateral isometric handgrip exercise at 30% MVC for 1min (1.340 ± 0.711μM, P < 0.05) and the unilateral isometric handgrip exercise at 20% MVC for 3min (0.798 ± 0.324μM, P < 0.05) are significantly higher than 30% of MVC for 2min. Blood pressure showed an inverse trend with oxygenation changes of the forearm muscle. The study indicates that the duration and muscle mass of isometric exercise are more effective on oxygenation responses and systematic blood pressure regulation, and suggests that the local muscle oxygenation factor following isometric contractions may mediate systematic blood pressure regulation.

Effect of handgrip isometric exercise training on reduction of resting blood pressure among individuals of different age groups

Abstract Background: Lifestyle choices, such as smoking, eating habits, alcohol consumption, and physical inactivity, have contributed to a global increase in hypertension throughout younger and older age groups. Isometric exercise is one of the nonpharmacological techniques for treating hypertension. It is less expensive, simpler, and takes less time. Aim: This study aimed to determine how handgrip isometric exercise training affects resting blood pressure (BP) in people of different ages and genders. Materials and Methods: For the study, 75 participants varying in age from 25 to 65 years were recruited. The study examined things including age, gender, maximum voluntary contraction, and BP. Patients who satisfied the study requirements were recruited and their BP variations (systolic BP [SBP] and diastolic BP [DBP]) were measured with a sphygmomanometer. Statistical Analysis: For normally distributed continuous variables, variables are described as mean and standard deviation. To compare SBP and DBP before and after exercise between weeks 1 and 4, the one-way analysis of variance and post hoc Tukey test were utilized. To investigate differences between males and females, an independent t test was used. A paired t test was performed to compare BP levels before and after activity training in the same group. P value of 0.05 was considered to be significant. Result: The study discovered that 4 weeks of isometric handgrip exercise training resulted in a significant decrease in resting BP. The data also show that the difference in resting BP reductions between different ages is not statistically significant (P &gt; 0.05), and there is no statistical difference in BP reduction between males and females. Conclusion: After 4 weeks of isometric handgrip exercise training, resting BP (SBP and DBP) decreased substantially. Furthermore, there is no statistically significant difference in resting BP reduction across age groups or genders, according to this study

Comparison of cardiovascular autonomic functions between type 2 diabetes mellitus patients and healthy individuals

Background: Type 2 diabetes mellitus is increasing day by day across the world. Cardiac autonomic neuropathy (CAN) is the most overlooked but the most debilitating complication of diabetes mellitus. If the chance of a diabetic patient to develop CAN in the future is diagnosed at an early stage of the disease, proper measures can be suggested which will delay the development of the complication. Aim and Objectives: The aim and objective of the study are to compare the cardiovascular autonomic functions between type 2 diabetes mellitus patients and normal individuals and to find whether cardiac autonomic neuropathy is present in type 2 diabetes mellitus patients. Materials and Methods: This cross-sectional study included 80 male individuals. Study participants were selected from patients attending diabetic clinics based on the inclusion criteria. A total of 80 subjects were selected out of which 40 were diabetic group and 40 were normal individuals. Cardiac autonomic functions were assessed using heart rate response to a change in posture and during the Valsalva maneuver, blood pressure response to a change in posture and during sustained isometric handgrip and heart rate variability (HRV) measurements were done using Kubios HRV analyzer software version 1.1. Results: Results were analyzed using IBM SPSS version 20 software. It was found that the resting systolic and diastolic blood pressure was found to have statistically significant higher values in the diabetic group. The mean and standard deviation of the Valsalva ratio were found to have statistically significant higher values in the diabetic group. The frequency domain parameters of HRV showed significant sympathetic predominance in the diabetic group. Conclusion: The need for early identification of cardiac autonomic neuropathy by various tests as well as the importance of lifestyle modifications were emphasized among all the participants of the study.

An Assessment of Maximal Isometric Hand Grip Strength and Upper Body Explosive Strength and Endurance in Various Ball Sports

Background. Playing with the ball and using hand-arm strength and power are very crucial for ball game players. It takes arm force and endurance, as well as isometric hand grip strength, to accomplish ball-game skills. Study purpose. The aim of the study was to evaluate maximal isometric hand grip strength, arm and shoulder explosive strength, and endurance in basketball, handball, and volleyball athletes. Materials and methods. The study randomly selected 135 male athletes, including 45 basketball, 45 handball, and 45 volleyball players, aged 17 to 24, all competing at the inter-university level. Hand grip strength (HGS) for both dominant (DHGS) and non-dominant (NDHGS) hands was measured using a JAMAR hydraulic hand grip dynamometer. An over-the-head seated medicine ball throw (SMBT) test assessed explosive arm strength, while a push-up (PU) test evaluated muscular strength and endurance. Results. The F-values (F) (2, 132) of DHGS, NDHGS, SMBT, and PU tests among basketball, handball, and volleyball players were .499 (p = .608); 1.166 (p = .315); 5.595 (p = .005); and 10.339 (p = .000), respectively. The results indicated that no notable distinctions were observed in DHGS and NDHGS among athletes in the three sports. However, considerable differences were found in the SMBT and PU tests. Conclusions. The study concluded that basketball, handball, and volleyball players’ maximum isometric hand grip strength was nearly the same, but in both cases, the handball player's mean value was superior to others. Upper-body explosive power, muscular strength, and endurance showed distinct differences from one group to another.

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.

Prevalence and prognostic impact of dynamic atrial functional mitral regurgitation assessed by isometric handgrip exercise.

In atrial functional mitral regurgitation (aFMR), a considerable proportion of patients displays a discrepancy between symptoms and echocardiographic findings at rest. Exercise testing plays a substantial role in assessing the haemodynamic relevance of mitral regurgitation (MR) and is recommended by current guidelines. Here, we aimed to assess the prevalence, extent, and prognostic impact of exercise-induced changes in patients with aFMR. Patients with at least mild MR who underwent handgrip exercise echocardiography at the University Hospital Duesseldorf between January 2019 and September 2021 were enrolled. Patients were followed up for 1 year to assess clinical outcomes. Eighty patients with aFMR were included [median age: 80 (77-83) years; 53.8% female]. The median N-terminal pro-brain natriuretic peptide level was 1756 (1034-3340) ng/L. At rest, half of the patients (53.8%) had mild MR, 20 patients (25.0%) had moderate MR, and 17 patients (21.2%) had severe MR. In approximately every fifth patient (17.5%) with non-severe MR at rest, the MR became severe during exercise. Handgrip exercise led to a reclassification of MR severity in 28 patients (35.0%). At 1-year follow-up, adverse events occurred more often in patients with severe MR at rest (76.5%) and exercise-induced dynamic severe MR (66.7%) than in those with non-severe MR (28.6%; P < 0.001). Handgrip exercise during echocardiography revealed exercise-induced changes in aFMR in every third patient. These data may have implications for therapeutic decision-making in symptomatic patients with non-severe aFMR at rest.

Pengaruh Isometric Handgrip Exercize Dan Terapi Nafas Dalam Terhadap Penurunan Tekanan Darah Pada Lansia Hipertensi

One of the non-communicable diseases that causes 71 percent of deaths globally, according to a report by The World Health Organization (WHO), is hypertension.. For the treatment of hypertension, there are both pharmaceutical and non-pharmacological options. There are a few non-pharmacological treatment options, including deep breathing exercises and isometric handgrip therapy. The aim of this study was to investigate the effectiveness of deep breathing exercises and isometric handgrip exercises in lowering blood pressure in elderly hypertensive patients in the Sokodadi District, Paiton, Probolinggo. This type of research is pre-experimental with a one-group pre-post design. The population of elderly people with hypertension in Sokodadi Village, as many as 42 respondents, determined the sample using a purposive sampling technique that fit the criteria of 38 respondents. The instrument used is the Isometric handgrip exercise module and deep breathing therapy. This study was analyzed with the Wilcoxon test. The study's findings demonstrated that the typical blood pressure before therapy was 157/97.4 mmHg, and the blood pressure value after therapy was 146.3/89.7 mmHg. According to the analysis test's Wilcoxon results, deep breathing exercises and therapy for hypertensive elderly people in Sokodadi district had a positive impact on lowering blood pressure. (p-value = 0.000 &lt; α = 0.05). In elderly hypertensive patients, isometric handgrip exercise and deep breathing therapy can lower blood pressure.

Hemodynamic changes in the temporalis and masseter muscles during acute stress in healthy humans.

Autonomic control of orofacial areas is an integral part of the stress response, controlling functions such as pupil dilatation, salivation, and skin blood flow. However, the specific control of blood flow in head muscles during stress is unknown. This study aims to investigate the hemodynamic response of temporalis and masseter muscles in response to five different stressors. Sixteen healthy individuals were subjected to a randomized series of stressors, including cold pressor test, mental arithmetic test, apnea, isometric handgrip, and post-handgrip muscle ischemia, while in the sitting posture. Finger-pulse photoplethysmography was used to measure arterial blood pressure, heart rate, and cardiac output. Near-infrared spectroscopy was used to measure changes in tissue oxygenation and hemoglobin indices from the temporalis and masseter muscles. All stressors effectively and significantly increased arterial blood pressure. Tissue oxygenation index significantly increased in both investigated head muscles during mental arithmetic test (temporalis: 4.22 ± 3.52%; masseter: 3.43 ± 3.63%) and isometric handgrip (temporalis: 3.45 ± 3.09%; masseter: 3.26 ± 3.07%), suggesting increased muscle blood flow. Neither the masseter nor the temporalis muscles evidenced a vasoconstrictive response to any of the stressors tested. In the different conditions, temporalis and masseter muscles exhibited similar hemodynamic patterns of response, which do not include the marked vasoconstriction generally observed in limb muscles. The peculiar sympathetic control of head muscles is possibly related to the involvement of these muscles in aggressive/defensive reactions and/or to their unfavorable position with regard to hydrostatic blood levels.

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.

High sensitivity cardiac troponin I in response to handgrip in women with signs and symptoms of ischemia with no obstructive coronary arteries

Abstract Background Women with signs and symptoms of ischemia and no obstructive coronary arteries (INOCA) are suspected to have myocardial ischemia, ∼10% have prior myocardial scar often in the absence of acute myocardial infarction (AMI) diagnosis and the development of heart failure with preserved ejection fraction (HFpEF) is relatively frequent. The mechanisms contributing to AMI and HFpEF progression are poorly understood in INOCA. Purpose To compare clinical, invasive, and high sensitivity cardiac troponin I (hsTnI) parameters in women with INOCA at rest and in response to isometric handgrip exercise. Methods Women with suspected INOCA underwent cannulation of the coronary sinus (CS), handgrip exercise testing and serial CS plasma sampling before, after 3 minutes of isometric handgrip stress at 30% of maximal voluntary contraction, and after 5 minutes of recovery. hsTnI was measured using a commercial immunoassay (R-PLEX, Meso Scale Discovery, Rockville, MD) and compared using t-tests. Results A total of 54 women with complete invasive data were included with a mean age of 53 ± 10 years, mean body mass index 28 ± 7 kg/m2. 20 women (37% of the cohort) had detectable CS hsTnI from baseline. Among these women, median values were elevated in response to handgrip (Figure) (baseline median 33.75 (IQR 18.12-67.75) pg/mL vs peak handgrip median 56.23 (IQR 32.84-97.83) pg/mL, signed rank p=0.0007, baseline vs recovery median 52.35 (IQR 32.59-106.27) pg/mL, signed rank p=0.0002). Conclusion Among women with INOCA, handgrip stress leads to an increase in hsTnI in more than a third, demonstrating objective evidence of myocardial injury. More work is needed to better understand contribution of coronary microvascular dysfunction to HFpEF progression.

Abstract 18068: Isometric Handgrip Exercise Myocardial Perfusion Reserve Correlates With Coronary Microvascular Dysfunction and Abnormal Left Ventricular Strain: A Report From the Women’s Ischemia Syndrome Evaluation Pre-Heart Failure With Preserved Ejection Fraction Study

Background: Impaired coronary artery response to isometric handgrip exercise (IHE) has previously been demonstrated to reflect endothelial dysfunction, an important contributor to ischemia with no obstructive coronary arteries (INOCA) and coronary microvascular dysfunction (CMD). Stress perfusion cardiac magnetic resonance (CMR) imaging is typically performed with pharmacologic stress using myocardial perfusion reserve index (MPRI) as a measure of CMD. IHE-MPRI has not been comprehensively studied in patients with INOCA, who are at risk for heart failure with preserved ejection fraction (HFpEF). Hypothesis: IHE-MPRI is related to CMD measured by pharm-MPRI and left ventricular (LV) structural and functional abnormalities in INOCA patients at risk for HFpEF. Methods: Participants with INOCA underwent comprehensive CMR with first-pass perfusion with adenosine or regadenoson, rest, and IHE. MPRI was adjusted to rest rate-pressure product (RPP). Lack of a satisfactory IHE response (defined as increase in heart rate≥10 bpm or systolic blood pressure ≥10 mmHg) was excluded. CMR measures of LV structure, function, MPRI, T1 and T2 mapping were analyzed using commercial software, blinded to clinical data. Pearson correlations were performed. Results: Of the participants (n=44) with IHE-MPRI, mean age was 55±11 years, body mass index 27±7 kg/m 2 , and 98% female, 31% hypertension, 12.5% diabetes, 19% hyperlipidemia. IHE-MPRI adjusted for rest RPP significantly correlated positively with pharm-MPRI and inversely with time to peak strain, diastolic strain measures and myocardial T2 ( Figure ). IHE-MPRI was not related to resting or IHE heart rate, systolic strain, LV mass, volumes, mass-volume ratio, native T1 or extracellular volume. Conclusion: IHE-MPRI relates to CMD and LV strain among patients with INOCA. Measurement of IHE-MPRI may improve understanding of CMD and LV structural and functional abnormalities that may contribute to development of HFpEF.

Abstract 14155: Handgrip Exercise Provoked High Sensitivity Cardiac Troponin I Increase in Women With No Obstructive Coronary Artery Disease: Relations to Myocardial Function

Background: Among women with signs and symptoms of ischemia and no obstructive coronary arteries (INOCA) around 10% develop heart failure with preserved ejection fraction (HFpEF). Mechanisms contributing to AMI and HFpEF progression in INOCA are poorly understood. Purpose: To characterize clinical profile and stress cardiac magnetic resonance imaging (CMRI) myocardial features of INOCA patients with and without increased troponin levels in response to handgrip exercise. Methods: Women with suspected INOCA underwent cardiac MRI and invasive coronary function testing (CFT), including coronary sinus (CS) cannulation, handgrip exercise testing, and serial CS plasma sampling before, after 3 minutes of isometric handgrip stress at 30% of maximal voluntary contraction, and after 5 minutes of recovery. High sensitivity cardiac troponin I (hsTnI) was measured using commercial immunoassay (R-PLEX, Meso Scale Discovery, Rockville, MD) and compared using t-tests. Results: A total of 51 women with complete data were included, of whom 31 (60.7%) had handgrip provoked increases in hsTnI levels from baseline, while 20 (39.2%) did not. Baseline characteristics are shown in Table. Patients with increased hsTnI levels had greater impaired global longitudinal strain rates and early diastolic strain rates (radial and circumferential) compared to those without increased hsTnI. No significant differences were observed in myocardial perfusion reserve index (MPRI). Conclusion: Women with INOCA demonstrating objective evidence of handgrip exercise provoked myocardial injury exhibit evidence of myocardial dysfunction not related to myocardial perfusion. Further prospective research is needed to understand the sequence of relations between coronary microvascular dysfunction contribution to HFpEF progression.

Validity and reliability of Squegg device in measuring isometric handgrip strength.

The quantitative measurement of handgrip strength is important in assessing and charting the progress of patients with neuromuscular diseases. The aim of this research was to determine the intra-rater and inter-rater reliability and the validity of the Squegg digital dynamometer. Twenty-one females and nine male participants with an age range between 18 and 40 years volunteered for the study. Three testers each took three measurements with a Squegg device and a Jamar dynamometer using standardized measurement techniques. Intra- and inter-tester reliability were calculated using the intra-class correlation coefficient (ICC). To investigate the relationship between hand measures and isometric handgrip strength, the Pearson correlation coefficient test was used. To determine the agreement between the two devices, a Bland Altman plot was constructed, and the concurrent validity of Squegg was calculated. The intra-rater reliability coefficients for both Jamar and Squegg were greater than 0.99 for all three testers, indicating excellent intra-rater reliability. The inter-rater reliability of Jamar (ICC=0.93) and Squegg (ICC=0.87) was excellent. With an ICC of 0.844 and an r-value of 0.720, Squegg with Jamar demonstrates good validity and statistical significance (p=0.001). The isometric handgrip strength and hand measures showed a moderate correlation in the study population. The Squegg isometric handgrip dynamometer has good concurrent validity and great intra- and inter-rater reliability in healthy individuals. The validity of Squegg in patients with neuromuscular diseases that affect hand function has to be investigated further.

The Influence of Branched-Chain Amino Acid Supplementation on Fatigue and Tryptophan Metabolism After Acute and Chronic Exercise in Older Adults: Protocol for a Pilot Randomized Controlled Trial.

Fatigue is a strong predictor of negative health outcomes in older adults. Kynurenine, a metabolite of tryptophan, is strongly associated with fatigue. Reductions in fatigue are observed with exercise; however, exercise training does not completely alleviate symptoms. Branched-chain amino acids (BCAAs) have been shown to have advantageous effects on exercise performance and compete with kynurenine for transport into the central nervous system. Thus, the combination of BCAA and exercise may exert synergized effects of mental and physical fatigue. Therefore, we hypothesize that BCAA added to exercise will shift kynurenine metabolism toward enhanced synthesis of kynurenic acid, thereby reducing fatigue. This randomized, double-blind, placebo-controlled trial aims to compare the effects of acute (approximately 45 min) and chronic (8 wk) exercise with and without BCAA supplementation on mental and physical fatigue and assess whether the hypothesized outcomes are modulated by changes in kynurenine metabolism in 30 older adults (n=15, 50% per group). Older adults (aged 60-80 y) who do not exercise >2 days per week and self-report fatigue (≥3 on a scale of 1-10) will be recruited. Participants will be randomized to either the exercise+BCAA group or exercise+placebo group. Participants will engage in high-volume, moderate-intensity, whole-body exercise training (aerobic and resistance exercise; either in-person or web-based sessions) 3 times per week for 8 weeks. In addition, participants will consume daily either 100 mg/kg body weight of BCAA (2:1:1 leucine:isoleucine:valine) or placebo (maltodextrin) throughout the 8-week intervention. BCAA and placebo powders will be identical in color and dissolved in 400 mL of water and 2.5 g of a calorie-free water flavor enhancer. Muscle biopsies will be collected before and after the intervention after a 12-hour fast to examine changes in the biomarkers of tryptophan metabolism and inflammation. Our primary outcomes include changes in mental and physical fatigue and metabolism after the 8-week exercise training between the 2 groups. Mental and physical fatigue will be measured before and after the intervention. Mental fatigue will be subjectively assessed through the completion of validated questionnaires. Physical fatigue will be measured by isometric handgrip, 1-repetition maximum, chair rise, 400-meter walk, and cardiopulmonary exercise tests. The study was funded in March 2022, with an anticipated projected data collection period lasting from January 2023 through December 2023. The discovery that kynurenine concentrations are associated with fatigue and are responsive to BCAA supplementation during exercise training could have important implications for the development of future interventions, both lifestyle and pharmacologic, to treat fatigue in older adults. ClinicalTrials.gov NCT05484661; https://www.clinicaltrials.gov/study/NCT05484661. DERR1-10.2196/52199.

Motor-Respiratory Coupling Improves Endurance Performance during Rhythmic Isometric Handgrip Exercise.

This study aimed to evaluate whether motor-respiratory coupling exists in rhythmic isometric handgrip exercises and its effect on endurance performance. In addition, the mechanism underlying observed effects was to be investigated if higher motor-respiratory coupling rate could enhance endurance performance. Eleven subjects completed three rhythmic isometric handgrip trials to task failure in a randomized manner. After one pretraining session to determine personal grip frequency, one trial was performed without respiration requirement (CON), and two trials were performed with inspiration-motor coupling (IMC) or expiration-motor coupling. Changes in maximal voluntary contraction (MVC) and EMG were used to measure neuromuscular fatigue. Force data during test were used to assess exercise intensity. Another 10 subjects completed electrical stimulation-induced finger flexion and extension during normal inspiration, normal expiration, fast inspiration, fast expiration, and breath holding. Force changes of different breathing conditions were compared. Normalized exercise time to exhaustion was significantly longer in IMC (1.27 ± 0.23) compared with expiration-motor coupling (0.82 ± 0.18) and CON (0.91 ± 0.18, P < 0.001). ΔMVC, grip frequency, force, and EMG indices were not different among conditions (all P > 0.05). Electrical stimulation-induced finger extensor force was significant higher during fast inspiration (1.11 ± 0.09) than normal respiration (1.00 ± 0.05) and fast expiration (0.94 ± 0.08, P < 0.05). IMC is an effective way to improve endurance performance of rhythmic handgrip exercise. This is likely due to a reduction in the energy consumption of motion control, as evidenced by similar peripheral fatigue in different conditions and modulation of corticospinal excitability by respiration.

Neuromuscular but Not Technical Performance is Affected by Time-of-Day in Semiprofessional, Female Basketball Players

ABSTRACT Purpose: The aim of this study was to determine whether variations in technical and neuromuscular performance occur across different times of the day in basketball players. Methods: Twenty semiprofessional, female basketball players (23 ± 4 years) competing in a second-division national basketball competition completed separate testing batteries in the morning (08:30) and in the afternoon (17:30) in a randomized counterbalanced order. Testing sessions consisted of a free-throw accuracy test to assess technical performance, as well as flexibility (ankle dorsiflexion range-of-motion test), dynamic balance (modified star excursion balance test), vertical jump height (squat jump, countermovement jump with and without arm swing), strength (isometric handgrip), change-of-direction speed (V-cut test), and linear speed (20-m sprint) tests to assess neuromuscular performance. Mechanism variables were also obtained including tympanic temperature, urinary specific gravity, and rating of perceived exertion at each session. Results: Squat jump height (6.7%; p = .001; effect size (ES) = 0.33), countermovement jump height with (4.1%; p = .018; ES = 0.27) and without arm swing (5.9%; p = .007; ES = 0.30), and 20-m sprint time (−1.4%; p = .015; ES = -0.32) were significantly superior in the afternoon compared to morning. Tympanic temperature was significantly higher in the afternoon than morning (1.4%; p < .001; ES = 1.31). In contrast, no significant differences between timepoints were evident for all remaining variables (p > .05; ES = -0.33 to 0.16). Conclusions: Some neuromuscular variables exhibited a time-of-day effect with better jump and sprint performance in the afternoon compared to morning in semiprofessional, female basketball players.

Adjusting for muscle strength and body size attenuates sex differences in the exercise pressor reflex in young adults.

Females typically exhibit lower blood pressure (BP) during exercise than males. However, recent findings indicate that adjusting for maximal strength attenuates sex differences in BP during isometric handgrip (HG) exercise and postexercise ischemia (PEI; metaboreflex isolation). In addition, body size is associated with HG strength but its contribution to sex differences in exercising BP is less appreciated. Therefore, the purpose of this study was to determine whether adjusting for strength and body size would attenuate sex differences in BP during HG and PEI. We obtained beat-to-beat BP in 110 participants (36 females, 74 males) who completed 2 min of isometric HG exercise at 40% of their maximal voluntary contraction followed by 3 min of PEI. In a subset (11 females, 17 males), we collected muscle sympathetic nerve activity (MSNA). Statistical analyses included independent t tests and mixed models (sex × time) with covariate adjustment for 40% HG force, height2, and body surface area. Females exhibited a lower absolute 40% HG force than male participants (Ps < 0.001). Females exhibited lower Δsystolic, Δdiastolic, and Δmean BPs during HG and PEI than males (e.g., PEI, Δsystolic BP, 15 ± 11 vs. 23 ± 14 mmHg; P = 0.004). After covariate adjustment, sex differences in BP responses were attenuated. There were no sex differences in MSNA. In a smaller strength-matched cohort, there was no sex × time interactions for BP responses (e.g., PEI systolic BP, P = 0.539; diastolic BP, P = 0.758). Our data indicate that sex differences in exercising BP responses are attenuated after adjusting for muscle strength and body size.NEW & NOTEWORTHY When compared with young males, females typically exhibit lower blood pressure (BP) during exercise. Adjusting for maximal strength attenuates sex differences in BP during isometric handgrip (HG) exercise and postexercise ischemia (PEI), but the contribution of body size is unknown. Novel findings include adjustments for muscle strength and body size attenuate sex differences in BP reactivity during exercise and PEI, and sex differences in body size contribute to HG strength differences.

Effects of exercise training on heart rate variability in individuals with lower extremity arterial disease and claudication: A systematic review

PurposeTo perform a systematic review of studies assessing the effects of regular exercise on heart rate variability (HRV) in individuals with lower extremity arterial disease (LEAD) and symptoms of claudication. MethodsA systematic search in the electronic databases MEDLINE, Embase, and Scielo, was conducted and updated on January 21, 2023. Randomized clinical trials investigating patients with LEAD and IC, assessing ≥ 4 wk of exercise interventions, and reporting at least one HRV measure (e.g., time or frequency domains) at baseline and follow-up were included. Two reviewers independently screened studies for inclusion, performed data extraction, and quality assessment of included studies. ResultsData from 7 trials were included (i.e., 5 walking, 1 resistance, and 1 isometric handgrip training), totaling 327 patients (66% males; range: 61 - 68 yr; ankle brachial index: 0.4 - 0.7). Following exercise training, three studies investigating walking training reported an increase in parasympathetic modulation indices and/or a decrease in sympathetic modulation indices (n = 2) as well as an increase in non-linear indices (n = 1). ConclusionThe current evidence is weak, and larger randomized controlled trials are needed to confirm the efficacy of exercise training in improving HRV. Additionally, the high divergence in the methodology of studies indicated the need for standard tools to improve the quality of HRV measurements in exercise trials. It is recommended to use standard procedures in future trials investigating HRV.

Acute effect of different doses of caffeinated chewing gum on exercise performance in caffeine-habituated male soccer players.

The ergogenic benefits of caffeine have been well established, but there is scarce research on its chewing gum form. The present research aimed to examine the effects of different doses (100 and 200 mg) of caffeinated chewing gum on muscle strength, vertical jump performance, and ball-kicking speed in trained male soccer players. In a double-blind, randomized counterbalanced, and crossover research design, 14 male soccer players (age = 22 ± 2 y; body mass = 74.2 ± 7.1 kg; height = 180.0 ± 6.8 cm; habitual caffeine intake = 358.9 ± 292.4 mg/day) participated in three experimental trials. In each trial, participants performed isometric handgrip strength, quadriceps and hamstring strength, ball-kicking speed, and 15 s countermovement jump test 10 min after chewing 100 mg (LCAF) or 200 mg (MCAF) of caffeinated gum or placebo (PLA). MCAF improved quadriceps strength (53.77 ± 5.77 kg) compared to LCAF (49.62 ± 8.81 kg, p = 0.048) and PLA (49.20 ± 7.20 kg, p = 0.032). However, neither LCAF nor MCAF had a significant effect on the isometric handgrip and hamstring strength, ball-kicking speed, and 15 s countermovement jump test (all p > 0.05). These findings support chewing gum as an alternative mode of caffeine administration which can be used as a nutritional ergogenic aid for trained soccer players, at least for quadriceps strength.