Assess Exercise Performance Research Articles

Smart Physiotherapy: Advancing Arm-Based Exercise Classification with PoseNet and Ensemble Models.

Telephysiotherapy has emerged as a vital solution for delivering remote healthcare, particularly in response to global challenges such as the COVID-19 pandemic. This study seeks to enhance telephysiotherapy by developing a system capable of accurately classifying physiotherapeutic exercises using PoseNet, a state-of-the-art pose estimation model. A dataset was collected from 49 participants (35 males, 14 females) performing seven distinct exercises, with twelve anatomical landmarks then extracted using the Google MediaPipe library. Each landmark was represented by four features, which were used for classification. The core challenge addressed in this research involves ensuring accurate and real-time exercise classification across diverse body morphologies and exercise types. Several tree-based classifiers, including Random Forest, Extra Tree Classifier, XGBoost, LightGBM, and Hist Gradient Boosting, were employed. Furthermore, two novel ensemble models called RandomLightHist Fusion and StackedXLightRF are proposed to enhance classification accuracy. The RandomLightHist Fusion model achieved superior accuracy of 99.6%, demonstrating the system's robustness and effectiveness. This innovation offers a practical solution for providing real-time feedback in telephysiotherapy, with potential to improve patient outcomes through accurate monitoring and assessment of exercise performance.

Auditing the representation of hormonal contraceptives in studies assessing exercise performance in women

ABSTRACT Hormonal contraceptive (HC) users have a different ovarian hormonal profile compared to eumenorrheic women. Due to the prevalence of HC use amongst sportswomen, there has been increased research efforts to understand their impact on exercise performance. The aim was to audit this research. Studies identified were assessed for HC type, athlete calibre, performance outcome, study design, and quality of methodological control regarding ovarian hormonal profiles. Sixty-eight different HCs were reported across 61 studies. Monophasic combined oral contraceptive (OCP) pills represented 60% of HCs, followed by other pills [34%, phasic-combined, progestogen-only, and un-specified], phasic and long acting reversible contraceptives [5%, vaginal ring, patch, implant, injection, intrauterine system] and unspecified HCs (1%). Eleven percent of participants using HCs were classified as highly trained or elite/international with no participants being classed as world class. Whilst the number of studies involving HCs has increased two-fold over the past decade, the number of studies ranked as gold standard has not increased (HC; 2003–57%, 2011–55%, 2022–43%. OCP; 2003–14%, 2011–17%, 2022–12%). Future research assessing HCs and exercise performance should adopt high-quality research designs and include a broader range of HCs in highly trained to world-class populations to increase the reach and impact of research in this area.

REGULAR LOW-DOSE CAFFEINE SUPPLEMENTATION DURING TRAINING DOES NOT PROVIDE ADDITIONAL BENEFIT TO SUBSEQUENT EXERCISE PERFORMANCE IN AUSTRALIAN RULES FOOTBALL ATHLETES

INTRODUCTION & AIMS Acute caffeine supplementation can improve exercise types like those completed by Australian Rules football (ARF) players during training. Hypothetically athletes could implement caffeine supplementation prior to training, allowing them to complete more training volume, improving adaptation and subsequent exercise performance. This study aimed to investigate the effect of regular low-dose caffeine ingestion pre-training during a training block on subsequent exercise performance. METHODS Twenty-nine male semi-professional ARF players were randomly allocated to a caffeine or placebo group. The four-week intervention period involved participants ingesting 2 mg·kg·BM-1 of caffeine or a placebo 60 min prior to two of their three weekly training sessions, which incorporated sport-specific conditioning and skills training. To assess exercise performance, a battery of tests was used before and after the intervention period including the Yo-Yo Intermittent Recovery Test Level 2 (YYIRT2), 20 m sprint and vertical jump (VJ). Performance differences were assessed using a linear mixed-effect model. RESULTS Mean session rating of perceived exertion (p = .24) and total training load (p =.53) were not different between caffeine and placebo groups over the intervention. There were no significant time x condition interaction effects for YYIRT2 accumulated distance (p = .87), or 5, 10 and 20 m sprint times (p =.06 - .44), however both caffeine and placebo groups improved YYIRT2 distance and sprint times following four weeks of training (p < 0.01). There was a significant effect for time showing decreased VJ performance (p < 0.01), with greater reductions in the placebo group (p = .03). CONCLUSION It is more beneficial to implement an effective training program for athletes rather than focusing effort on regular low-dose caffeine supplementation to augment the training stimulus. The training stimulus itself is typically greater for developing endurance and sprint effort performance, with supplemental caffeine showing no additional performance benefit.

Mechanisms underlying exercise intolerance in long COVID: An accumulation of multisystem dysfunction.

The pathogenesis of exercise intolerance and persistent fatigue which can follow an infection with the SARS-CoV-2 virus ("long COVID") is not fully understood. Cases were recruited from a long COVID clinic (N = 32; 44 ± 12 years; 10 (31%) men), and age-/sex-matched healthy controls (HC) (N = 19; 40 ± 13 years; 6 (32%) men) from University College London staff and students. We assessed exercise performance, lung and cardiac function, vascular health, skeletal muscle oxidative capacity, and autonomic nervous system (ANS) function. Key outcome measures for each physiological system were compared between groups using potential outcome means (95% confidence intervals) adjusted for potential confounders. Long COVID participant outcomes were compared to normative values. When compared to HC, cases exhibited reduced oxygen uptake efficiency slope (1847 (1679, 2016) vs. 2176 (1978, 2373) mL/min, p = 0.002) and anaerobic threshold (13.2 (12.2, 14.3) vs. 15.6 (14.4, 17.2) mL/kg/min, p < 0.001), and lower oxidative capacity, measured using near infrared spectroscopy (τ: 38.7 (31.9, 45.6) vs. 24.6 (19.1, 30.1) s, p = 0.001). In cases, ANS measures fell below normal limits in 39%. Long COVID is associated with reduced measures of exercise performance and skeletal muscle oxidative capacity in the absence of evidence of microvascular dysfunction, suggesting mitochondrial pathology. There was evidence of attendant ANS dysregulation in a significant proportion. These multisystem factors might contribute to impaired exercise tolerance in long COVID sufferers.

Cardiopulmonary exercise testing versus pulmonary function test in the assessment of respiratory impairment in chronic obstructive pulmonary disease patients.

Cardiopulmonary exercise testing (CPET) is a non-invasive method for the determination of disability and comprehensive evaluation of exercise responses involving the cardiovascular, pulmonary and musculoskeletal systems. To assess exercise performance measured by CPET in different chronic obstructive pulmonary disease (COPD) stages and to compare between pulmonary function test (PFT) and CPET in assessing the degree of respiratory impairment. Sixty patients diagnosed with COPD were enrolled in the study. Modified Medical Research Council scale (mMRC) and COPD assessment test (CAT) to evaluate dyspnea symptom. PFT and CPET were performed. There was a significant decrease in peak VO2 and anaerobic threshold in patients with stages III, IV (P < 0.001), while COPD stage I, II had significantly higher minute ventilation, tidal volume and oxygen pulse (P < 0.001). 76.67% of patients were similarly classified by CPET and PFT, while 23.33% were found to be less impaired according to CPET when compared to PFT. A significant correlation between both VE/VO2 (r = 0.31, 95% CI 0.19-0.92, P < 0.001) and VE/VCO2 (r = 0.69, 95% CI 0.86-1.08, P < 0.001) with FEV1. Whereas, an inverse correlation were found between both VE/VCO 2 (r = -0.34, 95% CI -0.77 -1.11, P < 0.001) and VE/VO2 (r = -0.55, 95% CI -0.88 to -0.15, P < 0.001), with the degree of air trapping as estimated by RV/TLC ratio. No significant correlation between neither CAT nor MRC and exercise testing parameters. CPET is an extremely valuable method for the determination of functional capacity and exercise intolerance in COPD rather than PFT. CPET is considered a gold-standard tool for better evaluation of respiratory impairment in COPD.

Assessment of fusion pacing on exercise capacity in patients with cardiac resynchronisation therapy devices

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): British Heart Foundation Local Departmental Research Funding Background Cardiac resynchronisation therapy (CRT) using fusion pacing requires correct timing of left ventricular pacing to right ventricular activation. The SyncAV™ algorithm, achieves this by dynamic reassessment of intrinsic atrio-ventricular (AV) conduction to adjust the paced/sensed AV delay. However, it is unclear whether AV optimisation maintains resynchronisation during exercise, or whether loss of fusion could lead to decreased exercise capacity. Cardio-pulmonary exercise testing (CPET) is the gold standard method for assessing exercise performance and can provide prognostic information in the heart failure population. Purpose We therefore used CPET measures of exercise capacity to compare the SyncAV™ algorithm to conventional pacing with fixed AV delays, in a double blinded, randomised crossover study (NCT03768804). Methods Patients at least 6 months post-CRT implant performed 2 CPET tests at least 1 week apart, with randomisation to either SyncAV™ with fusion pacing or conventional biventricular pacing with a fixed AVD of 120ms. All other programming was optimised to produce the narrowest QRS duration possible at rest in each case. Results Twenty patients (11 male, age 71 [65-77] years, median [interquartile range]) were recruited, with both ischaemic and non-ischaemic aetiology of heart failure. All had clinical and/or echocardiographic response to CRT. Optimised Fixed AVD and SyncAV™programming resulted in similar narrowing of QRS duration (QRSd) from intrinsic rhythm at rest (131 [103-137] vs 134 [110-137] ms for fixed AVD and SyncAV™ groups respectively, p=0.85). Overall, there was no difference in peak oxygen consumption (V̇O2peak) between programming (14.91 [12.61-18.16] vs 15.61 [12.18-19.70] ml/kg/min, p=0.19), or oxygen consumption at anaerobic threshold (VT1) (7.36 [6.93-8.94] vs 7.87 [6.77-9.24] ml/kg/min, p=0.42), or in the time to reach either V̇O2PEAK (p=0.81) or VT1 (p=0.39). The BORG rating of perceived effort was also similar between groups. CPET performance was also analysed comparing whichever programming gave the narrowest QRSd at rest (119 [96-136] vs 134 [119-142] ms, p&amp;lt;0.01). Eight were narrower with fixed AVD, 8 with SyncAV™ and in 4 there was no difference. QRSd during exercise (p=0.03), peak O2 pulse (ml/beat, a surrogate of stroke volume, p=0.03) and cardiac efficiency (watts/ml/kg/min, p=0.04) were significantly improved when programmed to the narrowest QRS duration at rest. Conclusion There is no significant difference in exercise capacity or QRSd between the use of optimised fixed AVD or SyncAV™, lending reassurance to fusion pacing being adequately maintained on exercise. In addition, programming with whichever algorithm gives the narrowest QRSd at rest is associated with a narrower QRSd during exercise, higher peak stroke volume and improved cardiac efficiency. This supports the use of SyncAV™ in the 40% of patients where this gave the narrowest QRSd at rest.

Continuous Lactate Monitoring System Based on Percutaneous Microneedle Array.

Lactate measurement is important in the fields of sports and medicine. Lactate accumulation can seriously affect an athlete’s performance. The most common problem caused by lactate accumulation in athletes is muscle soreness due to excessive exercise. Moreover, from a medical viewpoint, lactate is one of the main prognostic factors of sepsis. Currently, blood sampling is the most common approach to lactate measurement for lactate sensing, and continuous measurement is not available. In this study, a low-cost continuous lactate monitoring system (CLMS) is developed based on a percutaneous microneedle array that uses a three-electrode lactate sensor. The working electrode has an area of 10 mm × 6 mm, including a 3 × 3 array of stainless-steel microneedles. The length, width, and thickness of each needle are 1 mm, 0.44 mm, and 0.03 mm, respectively. The working electrode is then plated with gold, polyaniline, lactate enzyme, Nafion, and Poly(2-hydroxyethyl methacrylate) (poly HEMA). The reference electrode is a 2 × 1 array covered with AgCl, and the counter electrode is a 2 × 1 array plated with gold. The sensor is incorporated into the CLMS and connected to a smartphone application and the cloud. The CLMS was tested on 40 human subjects who rode indoor bicycles, starting at 100 W and increasing in steps of 25 W at intervals of 5 min until exhaustion. The data acquired from the app connected to the CLMS were analyzed to determine the subjects’ lactate response to exercise and the feasibility of assessing exercise performance and training exercise intensity by using the proposed system.

Assessment of the SyncAV fusion pacing algorithm on exercise capacity in patients with cardiac resynchronisation therapy device

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): British Heart Foundation (BHF) and Local Departmental Research Funding Background Fusion pacing as part of cardiac resynchronization therapy (CRT) requires correct timing of left ventricular pacing to right ventricular activation. The SyncAV algorithm, available in Quadra Allure and Assura CRT devices, is designed to allow optimal fusion pacing by dynamic reassessment of intrinsic atrio-ventricular (AV) conduction to adjust the paced/sensed AV delay. However, it is unclear whether AV optimisation continues to maintain resynchronisation during exercise, or whether potential loss of fusion pacing with changes in intrinsic AV conduction could lead to decreased exercise capacity. Cardio-pulmonary exercise testing (CPET) is the gold standard method for assessing exercise performance. Purpose To assess exercise capacity using the SyncAV algorithm for fusion pacing, compared with conventional biventricular pacing with fixed AV delays (AVD) for CRT. Methods Patients at least 6 months post-CRT implant were recruited in a prospective single-centre randomized single-blind crossover study. Patients performed 2 CPET tests at least 1 week apart, with randomization to either SyncAV with fusion pacing or conventional biventricular pacing with a fixed AVD of 120ms. All other programming was optimised to produce the narrowest QRS duration possible at rest in each case. Results Nine patients (5 male, age 70 ± 10 years, mean ± standard deviation) were recruited, with both ischaemic and non-ischaemic aetiology of heart failure. All had clinical or echocardiographic response to CRT. There was no difference in peak oxygen consumption (V̇O2max) between programming (1.47 ± 0.57 vs 1.50 ± 0.65 l/min for fixed AVD and SyncAV groups respectively, p = 0.59), or oxygen consumption at anaerobic threshold (VT1) (0.72 ± 0.20 vs 0.74 ± 0.25 l/min, p = 0.57). There was no difference in oxygen pulse (V̇O2/heart rate - a surrogate of stroke volume) at peak (12.3 ± 3.8 vs 13 ± 5.0 ml/beat , p = 0.28) or VT1 (8.4 ± 2.2 vs 8.7 ± 2.1 ml/beat, p = 0.67) and also no change in time to V̇O2max (1400 ± 491 vs 1367 ± 543 seconds, p = 0.38) or VT1 (518 ± 211 vs 534 ± 200 seconds, p = 0.75). Average heart rate at the median stage of exercise showed no difference between programming (96 ± 18 vs 93 ± 15 bpm respectively, p = 0.32). There was no difference in BORG Rating of Perceived Exertion (BORG-RPE) score at either peak exercise (median 19 [interquartile range (IQR) 2] vs 17 [IQR 2], p = 0.23) or at the median stage of exercise (median 13 [IQR 1] vs 13 [IQR 2], p = 0.30). Conclusion Fusion pacing using the SyncAV algorithm does not appear to improve exercise capacity compared to optimised conventional biventricular pacing with fixed AVD.

Intrauterine Contraception and Athletic Performance: Where is the data?

Background: Oral contraceptives (OCs) represent the most popular form of female contraception among the general and athletic populations. In female athletes, OCs are often used therapeutically to treat dysmenorrhea, which is perceived by many to affect training and performance. Recently, copper intrauterine devices (IUDs) and hormonal intrauterine systems (IUSs) have increased in popularity, and are now recommended by the Canadian Paediatric Society as a first-choice contraceptive. IUDs, however, present no therapeutic benefits with respect to dysmenorrhea, and may increase physical side effects associated with the menstrual cycle. Alternatively, IUSs have therapeutic application for dysmenorrhea, and therefore may present an option for athletes looking to reduce menstrual cycle symptoms. Purpose: To review the effects of IUDs and IUSs on exercise and athletic performance. Methods: Databases were searched using MeSH terms and key words in Boolean combinations. Studies were included if they 1) used a validated assessment of exercise performance (i.e., V02 max test, 1-repetition maximum, time to exhaustion), 2) included human participants who were moderately to very physically active (as assessed by a validated tool), and 3) used any copper IUD or hormonal IUS. Results: 245 titles were returned from the literature review; however, no studies met the inclusion criteria. Conclusion: The review returned limited relevant literature, and therefore, focuses on the theoretical bases of why IUDs and IUSs should be examined in the context of exercise and athletic performance. The need for future, experimental data exploring the effects of IUDs and IUSs on exercise and athletic performance is highlighted.

Exercise Training Combined with Bifidobacterium longum OLP-01 Supplementation Improves Exercise Physiological Adaption and Performance.

Probiotics exert multiple health benefits, including gastrointestinal health, immunoregulation, and metabolic disease improvement, by modulating microbiota to maintain eubiosis via the hypothalamic–pituitary–adrenal (HPA) and brain–gut–microbiome axes. Physiological fatigue, mental stress, and gastrointestinal discomfort under the demands of athletic performance as well as immunosuppression are common during endurance training and competition. Limited studies investigated the functional effects of probiotic supplementation on endurance training. Bifidobacterium longum subsp. Longum OLP-01 (OLP-01), isolated from an elite Olympic athlete, was combined with a six-week exercise training program with gradually increasing intensity. In this study, Institute of Cancer Research (ICR) mice were assigned to sedentary, exercise, OLP-01, or exercise + OLP-01 groups and administered probiotic and/or treadmill exercise training for six weeks to assess exercise performance, physiological adaption, and related metabolites. The exercise + OLP-01 group demonstrated higher performance in terms of endurance and grip strength, as well as improved fatigue-associated indexes (lactate, ammonia, creatine kinase (CK), lactate dehydrogenase (LDH), and glycogen content), compared with the other groups. OLP-01 supplementation significantly ameliorated inflammation and injury indexes (platelet/lymphocyte ratio (PLR), aminotransferase (AST), and CK) caused by prolonged endurance exercise test. Moreover, acetate, propionate, and butyrate levels were significantly higher in the exercise + OLP-01 group than in the sedentary and OLP-01 groups. Athletes often experience psychological and physiological stress caused by programed intensive exercise, competition, and off-site training, often leading to poor exercise performance and gastrointestinal issues. Functional OLP-01 probiotics are considered to be a nutritional strategy for improving physiological adaption, oxidative stress, inflammation, and energy balance to ensure high physical performance. Based on these results, probiotics combined with exercise training is a potential strategy for ensuring high physical performance of athletes, which should be further investigated through microbiota validation.

Effects of an Exogenous Ketone Supplement on Five-Kilometer Running Performance.

Numerous oral ketone supplements are marketed with the claim that they will rapidly induce ketosis and improve exercise performance. The purpose of this study was to assess exercise performance time and related physiological, metabolic and perceptual responses of recreational endurance runners after ingestion of a commercially available oral ketone supplement. Recreational endurance runners (n = 10; age: 20.8 ± 1.0 years; body mass: 68.9 ± 5.6 kg; height: 175.6 ± 4.9 cm) participated in a double-blind, crossover, repeated-measures study where they were randomized to 300 mg.kg-1 body weight of an oral β-hydroxybutyrate-salt + Medium Chain Triglyceride (βHB-salt+MCT) ketone supplement or a flavor matched placebo (PLA) 60 min prior to performing a 5-km running time trial (5KTT) on a treadmill. Time, HR, RPE, affect, RER, VO2, VCO2, and VE were measured during the 5-km run. The Session RPE and affect (Feeling Scale) were obtained post-5KTT. Plasma glucose, lactate and ketones were measured at baseline, 60-min post-supplement, and immediately post-5KTT. Plasma R-βHB (endogenous isomer) was elevated from baseline and throughout the entire protocol under the βHB-salt+MCT condition (p < 0.05). No significant difference (58.3 ± 100.40 s; 95% CI: -130.12 – 13.52; p = 0.100) was observed between the βHB-salt+MCT supplement (1430.0 ± 187.7 s) and the PLA (1488.3 ± 243.8 s) in time to complete the 5KTT. No other differences (p > 0.05) were noted in any of the other physiological, metabolic or perceptual measures.

P1779 Myocardial work is a predictor of exercise tolerance in patients with dilated cardiomyopathy and left ventricular dyssynchrony

Abstract Background the assessment of myocardial work (MW) by pressure-strain loops is a recently introduced tool for the assessment of myocardial performance. Aim of the present study is to evaluate the relationship between myocardial work and exercise tolerance in patients with dilated cardiomyopathy (DCM) Methods 51 patients with DCM (mean age 57 ± 13 years, left entricular ejection fraction : 32 ± 9%) underwent cardiopulmonary exercise test (CPET) to assess exercise performance. Trans-thoracic echocardiography (TTE) was performed CPET. The following indices of myocardial work (MW) were measured regionally and globally: constructive work (CW), wasted work (WW), and work efficiency (WE). Left ventricular (LV) dyssynchrony (DYS) was defined by the presence of septal flash or apical rocking at TTE. Results LV-DYS was observed in 16 (31%) patients and associated with lower LV ejection fraction (LVEF), GLS, global and septal WE, and higher global and septal WW (Table 1). In patients with LV-DYS, septal WE was the only predictor of exercise peak VO2max at multivariable analysis (Figure 1), whereas LVEF (β=0.47, p = 0.05) and age (β=-0.42, 47, p= 0.04) were predictors of exercise capacity in patients without LV-DYS. Conclusions In patients with DCM, LV-DYS is associated with an heterogeneous distribution of myocardial work. Septal WE is the best predictor of exercise performance in these patients. Table 1 All n = 51 No-dyssynchrony n = 35 (69%) LV-Dyssynchrony n = 16 (31%) p-value LVEF, % 32 ± 9 34 ± 10 28 ± 7 0.04 GLS, % -12 ± 3 -13 ± 3 -10 ± 3 0.001 GCW, mmHg% 1325 ± 398 1342 ± 354 1287 ± 491 0.65 GWW, mmHg% 201 ± 147 154 ± 95 304 ±191 &amp;lt;0.0001 GWE, % 85 ± 9 88 ± 7 78 ±10 &amp;lt;0.0001 CWsept, mmHg% 1172 ± 459 1274 ± 398 949 ± 516 0.017 CWlat, mmHg% 1518 471 1472 ± 386 1620 ± 622 0.30 WWsept, mmHg% 283 ± 275 174 ± 98 522 ±376 &amp;lt;0.0001 WWlat, mmHg% 135 ± 88 117 ± 81 176 ± 92 0.02 WEsept, % 78 ± 16 84 ± 9 62± 18* &amp;lt;0.0001 WElat, % 90 ± 7 91 ± 7 88 ± 7 0.16 Abstract P1779 Figure.

Myocardial work is a predictor of exercise tolerance in patients with dilated cardiomyopathy and left ventricular dyssynchrony.

The assessment of myocardial work (MW) by pressure-strain loops is a recently introduced tool for the assessment of myocardial performance. Aim of the present study is to evaluate the relationship between myocardial work and exercise tolerance in patients with dilated cardiomyopathy (DCM). 51 patients with DCM (mean age 57 ± 13 years, left ventricular ejection fraction: 32 ± 9%) underwent cardiopulmonary exercise test (CPET) to assess exercise performance. 22 patients (43%) had left or right bundle branch block with QRS duration > 120ms. Trans-thoracic echocardiography (TTE) was performed before CPET. The following indices of myocardial work (MW) were measured regionally and globally: constructive work (CW), wasted work (WW), and work efficiency (WE). Left ventricular dyssynchrony (LV-DYS) was defined by the presence of septal flash or apical rocking at TTE. LV-DYS was observed in 16 (31%) patients and associated with lower LV ejection fraction (LVEF), lower global and septal WE, and higher global and septal WW. In patients with LV-DYS, septal WE was the only predictor of exercise capacity at multivariable analysis (β = 0.68, p = 0.03), whereas LVEF (β = 0.47, p = 0.05) and age (β = - 0.42, p = 0.04) were predictors of exercise capacity in patients without LV-DYS. In patients with DCM, LV-DYS is associated with an heterogeneous distribution of myocardial work. Septal WE is the best predictor of exercise performance in these patients.

Exercise Performance as a Predictor for Balance Impairment in COPD Patients.

Background and objective: Six-minute walk test (6-MWT) is a widely used test for assessing exercise performance in chronic obstructive pulmonary (COPD). However, the association between reduced walking distance and balance impairment in COPD has not been directly investigated. Therefore, the aim of this study was to identify exercise performance as a predictor for balance impairment in COPD. Materials and Methods: The cross-sectional study was conducted at a single visit involving stable COPD patients in Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand from November 2015 to October 2017. The 6-MWT was measured for in all subjects. The prognostic confounding factors were also collected for all subjects. Balance test was measured using the Berg Balance Scale (BBS) and the Timed Up and Go (TUG) test. A cut-off score of BBS < 46 and/or the TUG ≥ 13.5 s was classified as balance impairment. Multivariable logistic regressions were performed to identify the six-minute walk distance (6-MWD) as a predictor for balance impairment in COPD. Results: Of the 176 COPD subjects assessed for eligibility, 118 COPD patients were enrolled including 86 males (72.9%) with a mean age of 73.5 ± 8.1 years. Thirty-three (28.0%) cases were classified with a balance impairment. The 6-MWD < 300 m was the predictor of balance impairment in COPD with an adjusted risk ratio of 10.10 (95%CI; 2.87, 35.61, p-value < 0.001). Conclusions: The 6-MWT is not only useful for evaluation of exercise performance, but also for prediction of balance impairment in patients with COPD. Our study suggests that the 6-MWD < 300 m is an important risk factor for balance impairment in COPD.

The reduced bactericidal activity of neutrophils as an incisive indicator of water-immersion restraint stress and impaired exercise performance in mice

The incisive evaluation of psychological stress may be required to determine the exercise performance of stressed hosts. We investigated objective markers of psychological stress that reflect exercise performance, focusing on the neutrophil function. We used murine water-immersion restraint (WIR) stress for our assessments. After receiving WIR for 1 or 2 h, mice were exercised on an airtight treadmill that monitors their respiratory exchange ratio. The neutrophil function was analyzed after WIR stress. Although the control mice (without WIR) showed good combustion of both carbohydrates and lipids as energy sources during treadmill exercise, mice that underwent 2-h WIR did not combust carbohydrates or lipids effectively, drastically reducing their performance. In contrast, the 1-h WIR mice showed carbohydrate combustion (albeit a slow response) but did not use lipids for energy, thereby running longer than the 2-h WIR mice but shorter than the control mice. The bactericidal activity of neutrophils, but not their superoxide production or microsphere-phagocytic activity, was significantly reduced by 1-h WIR and further reduced by 2-h WIR, indicating a significant association between WIR stress and exercise performance. The neutrophil bactericidal activity may be a good indicator of psychological stress and a useful tool for precisely assessing exercise performance.

Aerobic capacity and exercise performance in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is one of the leading causes of chronic liver disease worldwide. Exercise has proven effective in treating NAFLD, and many clinical initiatives seek to increase uptake of exercise in this population. This study aimed to elucidate the physiological responses of individuals with NAFLD to graded exercise testing. Seventeen participants with presumed NAFLD and 15 without were assessed through symptom-limited, Modified Bruce treadmill testing. Gas exchange, impedance cardiometry, and perceived exertion ratings were used to assess exercise performance, response and perception. Patient-self reports were also obtained. Individuals with NAFLD were older (49.00 [38.50, 54.50] vs. 30.00[22.00, 42.00] years, P=0.018) with higher Body Mass Index (32.54[27.38, 34.98] vs. 25.62[23.76, 30.72], P=0.012), but demonstrated no other differences with regards to sex, race, blood pressure, resting heart rate, or habitual activity. Individuals demonstrated no between-group differences in total exercise time, anaerobic threshold (AT) onset time, or cardiac output. While individuals with NAFLD displayed a decreased peak oxygen consumption (VO2) (25.70[23.60, 27.20] vs. 31.00[26.00, 42.70], P=0.036) relative to controls, a similar difference was not found for the percentage of predicted VO2max achieved, suggesting that NAFLD may not impair exercise physiology beyond what is observed in obese individuals. Exercise capacity appears preserved in participants with NAFLD relative to their control counterparts. Peak VO2 is reduced among these patients, suggesting impaired aerobic capacity. Future studies may seek to determine whether this finding is directly related to the diagnosis of NAFLD, or more generally to states of obesity and physical deconditioning.

Determinants of Exercise Performance in Children and Adolescents with Repaired Tetralogy of Fallot Using Stress Echocardiography.

Exercise performance is variable and often impaired in patients with repaired tetralogy of Fallot (rTOF). We sought to identify factors associated with exercise performance by comparing high to low performers on cardiopulmonary exercise testing (CPET) in patients with rTOF. We conducted a cross-sectional study of subjects presenting for CPET who underwent echocardiograms at rest and peak exercise. Patients with pacemakers and arrhythmias were excluded. Right ventricular (RV) global longitudinal strain was used as a measure of systolic function. Pulmonary insufficiency (PI) was assessed with the diastolic systolic ratio and the diastolic systolic time-velocity integral ratio by Doppler interrogation of the pulmonary artery. CPET measures included percent-predicted maximum [Formula: see text][Formula: see text], percent-predicted maximum work and oxygen pulse. High versus low performers were identified as those achieving [Formula: see text] of at least 80% or falling below, respectively. Differences in echocardiographic parameters from rest to peak exercise were examined using mixed-effects regression models. Compared to the low performers (n = 17), high performers (n = 12) were younger (12.8 ± 3.3years vs. 18.3 ± 4.8years), had normal chronotropic response (peak heart rate > 185bpm) with greater heart rate reserve and superior physical working capacity. High performers also had a greater reduction in PI at peak exercise, despite greater PI severity at rest. Oxygen pulse was comparable between groups. For both groups, there was no association of PI severity and RV systolic function at rest with exercise parameters. There was no group difference in the magnitude of change in RV strain and diastolic parameters from rest to peak exercise. Chronotropic response to exercise appears to be an important parameter with which to assess exercise performance in rTOF. Chronotropic health should be taken into consideration in this population, particularly given that RV function and PI severity at rest were not associated with exercise performance.

Validation of 4-meter-gait-speed test and 5-repetitions-sit-to-stand test in patients with pulmonary fibrosis: a clinimetric validation study.

Background and objective: Patients with pulmonary fibrosis (PF) have a clear exercise intolerance. The 4-meter-gait-speed (4MGS) test and the 5-repetitions-sit-to-stand (5STS) test are easy, inexpensive and reliable measures of functional performance. Both tests have been validated in healthy adults and patients with chronic obstructive pulmonary disease. 4MGS test and 5STS test have not been studied in patients with PF. Methods: In this cross-sectional clinimetric validation study 51 PF patients conducted in random order the 4MGS test, 5STS test and the 6-min walk test (6MWT) on a single day. Additionally, body weight, height, lean body mass, health-related quality of life, disease severity, handgrip strength, dyspnoea and leg fatigue were assessed. The setting was a tertiary referral center for Interstitial Lung Diseases. Results: Patients had a diagnosis of idiopathic pulmonary fibrosis (IPF, 37%), PF other than IPF (47%), or unclassified (16%). Patients walked 453±111m in six minutes. Moreover, it took the patients 2.0±0.5s to walk 4 m, and 12.0±3.8s for the 5STS test. The 4MGS test (r = 0.77; p<0.01) and the 5STS test (r = -0.41; p<0.01) correlated significantly with the distance walked in 6MWT. Indeed, 4MGS combined with handgrip strength and Medical Research Council dyspnoea grade could explain 75% of the variance in 6MWD. Conclusions: 4-meter-gait-speed and 5-repetitions sit-to-stand are significantly and independently correlated with the 6-minute walk distance in patients with pulmonary fibrosis. Indeed, 4-meter-gait-speed test may serve as a simple initial field test to assess exercise performance in patients with pulmonary fibrosis. (Sarcoidosis Vasc Diffuse Lung Dis 2018; 35: 317-326)

Nicotine effects on exercise performance and physiological responses in nicotine-naïve individuals: a systematic review.

The purpose of this systematic review was to evaluate the effects of smokeless forms of nicotine on physiological responses and exercise performance. Methodology and reporting were based on the PRISMA statement. The intervention was defined as any product containing nicotine that did not require smoking. Searches were conducted across two electronic databases with supplementary approaches utilized. Studies were selected following set inclusion and exclusion criteria and checked by two independent authors. A modified PEDro scale was utilized to rate study quality with studies averaging 9·3/13. Six studies assessed exercise performance with endurance-based parameters reported as significantly improved with nicotine in one study, while anaerobic parameters were unaffected or decreased compared to placebo except in one study which reported enhanced leg extensor torque but no effect on countermovement jump or Wingate anaerobic capacity. Sixteen of 28 studies investigating physiological responses reported that nicotine significantly increased heart rate compared to placebo or control. Blood pressure and blood flow were also reported as significantly increased in multiple studies. While there is strong evidence of nicotine-induced changes in physiological function that would benefit physical performance, beneficial effects have only been reported on leg extensor torque and endurance performance by one study each. Subsequently, there is need for more research with strong methodological quality to definitively evaluate nicotine's potential as an ergogenic aid.

Is cardiorespiratory fitness impaired in PCOS women? A review of the literature.

Polycystic ovary syndrome (PCOS) is a common and heterogeneous endocrine disorder, affecting 8-12% of reproductive-aged women. Insulin resistance and body fat excess are common features in these subjects. Increased physical activity and diet modifications are the first recommended approach in the management of these women, at least in overweight/obese subjects. Evaluation of cardiorespiratory fitness (CRF) is important in assessing exercise performance and in monitoring the effects of physical exercise interventions. Several studies have shown that CRF may be impaired in metabolic and endocrine disorders. However, there are little data on this issue in PCOS women. The aim of this narrative review is to critically evaluate whether aerobic capacity is altered in PCOS women, focusing on maximal oxygen uptake. An updated search of the literature was performed, identifying papers with maximal oxygen consumption measurements in women with PCOS compared to healthy controls. We have identified six studies on this specific topic: four of them showed an alteration of maximal oxygen consumption in PCOS women, whereas two did not. However, taken together these studies suggest that CRF may be strikingly impaired in both normal-weight and overweight/obese subjects with this condition. Women with PCOS appear to be characterized by a reduced cardiopulmonary fitness. However, further research on this topic is needed. This information may hopefully help clinicians and exercise specialist in planning individualized exercise programs aimed at improving the metabolic and endocrine outcomes in these women.