Fatigue Index Research Articles

Development of Athlete Health Monitoring and Early Warning System Based on Sensor Data

An athlete health monitoring and early warning system based on sensor data utilizes wearable sensors to track various physiological parameters, such as heart rate, body temperature, oxygen saturation, and movement patterns. These sensors continuously collect real-time data during training sessions and competitions. Machine learning algorithms analyze the data to detect deviations from normal patterns and identify potential indicators of injury, fatigue, or overtraining. By monitoring athletes' health parameters over time and comparing them to established baseline values, the system can provide early warnings of potential health issues or performance declines. Coaches and medical staff can then intervene promptly with appropriate interventions, adjustments to training loads, or rest periods to prevent injuries and optimize athletes' performance and well-being. . The paper introduces the Reliable Fuzzy Sensor Optimized Automated Monitoring (RFSO-DL) system, a novel approach to athlete health monitoring leveraging fuzzy logic and sensor data optimization techniques. RFSO-DL offers a comprehensive solution for real-time assessment of athlete well-being by analyzing physiological measurements and activity levels. Through a series of experiments, the system demonstrates high accuracy, precision, recall, and F1 score in classifying athlete health status. Results indicate RFSO-DL's effectiveness in capturing subtle variations in health status and providing timely interventions. Through experiments, the system achieves impressive results, with accuracy ranging from 90.5% to 94.1%, precision from 85.8% to 91.2%, recall from 91.7% to 95.6%, and F1 score from 88.6% to 93.3%. These findings underscore RFSO-DL's potential to revolutionize athlete health monitoring by accurately classifying health status based on physiological measurements and activity levels.

Effectiveness of a Voice Training Program for Religious Officials in Turkey.

This study examines the effectiveness of a voice training program designed for Islamic religious officials, who are occupational voice users with a significant vocal load. The participants included 34 healthy religious officials whose acoustic measures were within normal voice ranges for healthy adults (jitter < 1%; shimmer < 3%) and reported no voice complaints. Participants were randomly divided into two groups (experimental, n = 17; control, n = 17). The two-stage voice training program consisted of 32 sessions over 8 weeks with informative and voice exercise stages. Objective and subjective voice measurements were performed at the beginning and end of the research. Objective measurements included fundamental frequency, percentage of vocal pitch perturbation (jitter), percentage of vocal intensity perturbation (shimmer), and harmonics-to-noise ratio. Subjective voice measurements included the Singing Voice Handicap Index, Vocal Fatigue Index (VFI), and Voice-Related Quality of Life (V-RQoL) scores. All initial measurements other than VFI scores were within acceptable limits for both groups. There were no significant differences between the groups initially (p > 0.05) and no significant changes in the control group in the second evaluation (p > 0.05). However, there was significant improvement in the experimental group after the training program in all measures, including VFI scores (p < 0.05). This study shows the positive results of a voice training program. Voice training should be integrated into the formal education of occupational voice users or in-service training programs of relevant institutions.

Caffeinated Chewing Gum Improves Basketball Shooting Accuracy and Physical Performance Indicators of Trained Basketball Players: A Double-Blind Crossover Trial.

(1) Background: This study investigated the effects of caffeinated chewing gum on the basketball-specific performance of trained basketball players. A double-blind, randomized crossover design was employed. (2) Methods: Fifteen participants (age: 20.9 ± 1.0 years; height: 180.9 ± 5.4 cm; mass: 77.2 ± 7.5 kg; training age: 8.2 ± 0.3 years) were recruited and divided into a caffeine trial (CAF) and placebo trial (PL). The participants in the CAF trial chewed gum containing 3 mg/kg of caffeine for 10 min, while those in the PL trial chewed a placebo gum without caffeine. Following a 15 min rest, all the participants completed basketball-specific performance tests. (3) Results: The free throw accuracy for the CAF trial was significantly higher than that for the PL trial (CAF: 79.0 ± 4.31%; PL: 73.0 ± 9.16%; p = 0.012; Cohen's d = 0.94). Additionally, the CAF trial demonstrated significantly better performance in the 20 m segmented dash (CAF: 2.94 ± 1.12 s; PL: 3.13 ± 0.10 s; p < 0.001; Cohen's d =1.8) and squats (p < 0.05), and exhibited lower fatigue indexes (CAF: 3.6 ± 1.6%; PL: 5.2 ± 1.6%; p = 0.009; Cohen's d =1.0). (4) Conclusions: These findings suggest that chewing gum containing 3 mg/kg of caffeine offers moderate-to-large improvements in key performance aspects relevant to professionally trained basketball players.

Machine learning-based fatigue life prediction of lamellar titanium alloys: A microstructural perspective

Fatigue life prediction based on the traditional empirical formulation in large fatigue regimes is limited and prone to over-fitting. In this regard, we propose an integrated approach for fatigue life prediction of lamellar titanium alloys incorporating crystal plasticity simulations and a variety of machine learning methods from a microstructural perspective. Firstly, various defect shapes and distinct lamellar distributions are employed to characterize fatigue performance under different microstructural features. By utilizing fatigue indicator parameters (FIPs) to get an expanded dataset, this work employs algorithms including artificial neural networks (ANN), random forests regression (RFR), support vector regression (SVR), and particularly convolutional neural networks (CNN) to predict fatigue life. The results indicate that CNN outperforms the previously mentioned algorithms in prediction accuracy, due to its ability to directly extract microstructural features from images. Our proposed approach provides a microstructural perspective for fatigue life prediction of lamellar titanium alloys, broadening the way for life assessment of materials with diverse microstructures.

A hybrid approach integrating genetic algorithm and machine learning to solve the order picking batch assignment problem considering learning and fatigue of pickers

Modeling human behaviors has become increasingly relevant to improving the performance of manual order-picking systems. However, although a vast corpus of literature has recently started to consider the human factors in these systems, several gaps remain uncovered. Specifically, mental and physical human factors, like learning and fatigue, and quantitative and spatial features of picking orders have never been considered jointly to estimate the time a human order picker requires to execute a specific picking mission. Furthermore, little attention has been given to assigning and sequencing orders to pickers to minimize the picking time acting on their individual learning and fatigue characteristics. This study thus proposes a novel approach integrating machine learning and genetic algorithms to solve the problem. A non-linear machine learning-based predictive model has been adopted to predict the picking time of batches of orders based on quantitative and spatial features of batches and learning and fatigue indicators of pickers. These predictions have thus been adopted to guide a genetic algorithm to find the best assignment of future planned batches of orders to pickers. One year of picking data collected from the warehouse of a grocery retailer has been adopted to investigate the potential of the proposed approach. Furthermore, multiple comparisons have been performed. First, the advantages of predicting the batch-picking time with the proposed non-linear model have been compared with predictions executed based on linear models. In addition, an ablation analysis has been performed to investigate the advantages of predicting the batch picking time while simultaneously considering the quantitative and spatial features of batches and the learning and fatigue indicators of pickers. Moreover, the advantages of the proposed batch assignment strategy, which considers learning and fatigue indicators, have been compared with an assignment strategy that does not optimize these elements. Lastly, an explainability analysis of the predictive model has been performed to understand how and how much quantitative and spatial features of batches and learning and fatigue indicators of pickers affect the batch picking time.

Effectiveness of aerobic training with blood flow restriction and ischemic preconditioning on anaerobic performance

The aim of the study was to analyze the effectiveness of aerobic training (AT) with restricted blood flow (BFR+AT) and ischemic preconditioning (PCI+AT) on the anaerobic performance of non-exercising individuals. This is a longitudinal study, with a sample of 23 sedentary men (age= 30.0 ± 5.57 years; = 1.77 ± 0.07 m; body mass= 91.10 ± 18.66 kg), who underwent specific aerobic power tests in vertical cycloergometer, step and treadmill. An aerobic training program was carried out for 4 weeks. The subjects were randomized into three groups: BFR+AT: continuous at 50% of the auscultatory pulse; PCI+AT: three cycles of 05' min of vascular occlusion/reperfusion at 220 mmHg; Control: AT without BFR. All groups performed the same training (6' min per ergometer with 45" min interval at an intensity of 50% of VO2max). Anaerobic performance was verified using the RAST TEST, analyzing the measurements of lactate (La), peak power (PP) and fatigue index (%F). There were significant differences in La Pre vs Post levels (∆ =40%) in the PCI group; an increase was noted in PP (∆=23%) compared to the other groups; there was no significant difference in any of the groups in the F variable. However, there was a greater tendency to fatigue in the Control group (∆=23%). Aerobic training with restricted blood flow and ischemic preconditioning has been shown to be effective in improving anaerobic performance, considering lactate levels, peak power. However, the fatigue index showed a greater tendency of decreasing fatigue, thus improving the anaerobic capacity of individuals without regular physical practice.

Inhibition of Metalloproteinases Extends Longevity and Function of In Vitro Human iPSC-Derived Skeletal Muscle.

In vitro culture longevity has long been a concern for disease modeling and drug testing when using contractable cells. The dynamic nature of certain cells, such as skeletal muscle, contributes to cell surface release, which limits the system's ability to conduct long-term studies. This study hypothesized that regulating the extracellular matrix (ECM) dynamics should be able to prolong cell attachment on a culture surface. Human induced pluripotent stem cell (iPSC)-derived skeletal muscle (SKM) culture was utilized to test this hypothesis due to its forceful contractions in mature muscle culture, which can cause cell detachment. By specifically inhibiting matrix metalloproteinases (MMPs) that work to digest components of the ECM, it was shown that the SKM culture remained adhered for longer periods of time, up to 80 days. Functional testing of myofibers indicated that cells treated with the MMP inhibitors, tempol, and doxycycline, displayed a significantly reduced fatigue index, although the fidelity was not affected, while those treated with the MMP inducer, PMA, indicated a premature detachment and increased fatigue index. The MMP-modulating activity by the inhibitors and inducer was further validated by gel zymography analysis, where the MMP inhibitor showed minimally active MMPs, while the inducer-treated cells indicated high MMP activity. These data support the hypotheses that regulating the ECM dynamics can help maximize in vitro myotube longevity. This proof-of-principle strategy would benefit the modeling of diseases that require a long time to develop and the evaluation of chronic effects of potential therapeutics.

Crystal plasticity modeling fatigue behavior in bimodal Ti–6Al–4V: Effects of microdefect and lamellar orientation

AbstractInvestigating fatigue failure in titanium alloys is crucial for material design and engineering. Fatigue behavior in dual‐phase titanium alloys is strongly correlated with microstructural features and microdefects. This work formulates an improved modeling method to investigate fatigue behavior of bimodal Ti–6Al–4V, emphasizing the effects of lamellar orientation and microdefects. Using an improved Voronoi tessellation method, we establish representative volume element (RVE) models with various grain size distributions. Crystal plasticity finite element modeling (CPFEM) is used to analyze fatigue deformation in bimodal Ti–6Al–4V, considering microdefects and lamellar orientation. Fatigue indicator parameters are then incorporated into CPFEM to predict fatigue life and verified with experimental data. Numerical results highlight the significant influence of lamellar orientation and microdefects on fatigue behavior, with predicted life within the 3‐error band. This method efficiently overcomes challenges in quantitatively characterizing microstructural lamellae that experiments are short of, paving the way for designing fatigue‐resistant alloy materials with similar microstructures.

Effects of Hormonal Contraception and the Menstrual Cycle on Fatigability and Recovery From an Anaerobic Exercise Test.

Cabre, HE, Ladan, AN, Moore, SR, Joniak, KE, Blue, MNM, Pietrosimone, BG, Hackney, AC, and Smith-Ryan, AE. Effects of hormonal contraception and the menstrual cycle on fatigability and recovery from an anaerobic exercise test. J Strength Cond Res 38(7): 1256-1265, 2024-This study sought to evaluate the effects of oral contraceptive (OC) and hormonal intrauterine device (H-IUD) use, compared with a eumenorrheic (EUM) cycle, on fatigability and recovery between hormone the phases. Peak power (PP), average power (AP), fatigue index (FI), blood lactate, vessel diameter, and blood flow (BF) were measured from a repeated sprint cycle test (10 × 6 seconds) in 60, healthy, active women (mean ± SD ; age: 26.5 ± 7.0 years, BMI: 22.5 ± 3.7 kg·m -2 ) who used monophasic OC (≥6 months; n = 21), had a H-IUD (≥6 months; n = 20), or had regular naturally occurring menstrual cycle (≥3 months) or had a nonhormonal IUD (EUM; n = 19). Subjects were randomly assigned to begin in either the low-hormone phase (LHP) or high-hormone phase (HHP) and were tested once in each phase. Separate univariate analyses of covariances assessed the change from HHP to LHP between the groups, covaried for progesterone, with significance set at p ≤ 0.05. All groups demonstrated similar changes in PP, AP, FI, blood lactate, vessel diameter, and BF between the phases ( p > 0.05). Although not significant, AP was higher in LHP for OC (Δ -248.2 ± 1,301.4 W) and EUM (Δ -19.5 ± 977.7 W) and higher in HHP for H-IUD (Δ 369.3 ± 1,123.0 W). Oral contraceptive group exhibited a higher FI (Δ 2.0%) and reduced blood lactate clearance (Δ 2.5%) in HHP. In recreationally active women, hormonal contraception and hormone phases may minimally impact fatigue and recovery. Individual elite female athletes may benefit from understanding hormonal contraception type as performance and recovery may slightly vary across the cycle.

Effects of fasting during Ramadan month on soccer-specific technical performance, cognitive function, and perceptions in soccer players

ABSTRACT We aimed to examine the effects of Ramadan fasting (RF) and high-intensity short-term maximal performance on elite soccer players’ shooting accuracy, executive function (EF), and perceptions. Sixteen Muslim elite players fasting during Ramadan underwent assessments before (BR), during (DR), and after Ramadan (AR). Soccer-specific technical performance was evaluated using the Loughborough Soccer Shooting Test (LSST) before and after a 5-metre shuttle run test (5mSRT), conducted at the same time-of-day (17:00 h). Performance metrics recorded included higher distance (HD), total distance (TD), and fatigue index (FI). RPE after a 5-min warm-up and each repetition of the 5mSRT were obtained, and the mean RPE score was calculated. Trail Making Test (TMT Parts A and B) were used after the warm-up and the 5mSRT. Perceived difficulty (PD) was assessed following the LSST. HD, TD, and FI were not affected by RF (p > 0.05). DR, RPE and accuracy scores in the LSST were significantly lower after the 5mSRT compared to BR (1.29 vs. 1.24 AU; 1.29 vs. 1.24, respectively). In conclusion, RF had no adverse effects on physical performance. However, when combined with high-intensity running sessions, RF may impact accuracy and PD, and these adverse effects seem to have been translated into EF.

Combined futsal training

A training model that combines physicality and tactics is really needed in futsal. This study aims to analyse the effect of rotation play training with HIIT Protocol on the anaerobic abilities of amateur futsal players. This research uses an experimental method with a two-group pre-test and post-test design. The sample in this study consisted of 30 amateur futsal players with an age of 19.23 ± 0.57 years, height of 165.60 ± 5.63 cm, body mass of 59.17 ± 5.24 kg, and BMI of 21.60 ± 1.93. Samples were divided randomly into an experimental group (EG) and a control group (CG). Data analysis used a Paired Sample T-test and an Independent T-test with a significance level of .05 and used Cohen's ES to measure the magnitude of differences between groups. This study used the running anaerobic sprint test (RAST). The variables in RAST that will be analysed are Peak Power (W); Mean Power (W); Peak Power per Weight (W.kg-1); Mean Power per Weight (W.kg-1); Fatigue Index (%); Total effort time (s). The paired sample t-test resulted in a significant difference in EG with significance values of Peak Power p = .010, Mean Power p = .007, Peak Power per Weight p = .011, Mean Power per Weight p = .008, Fatigue Index p = .045, and total effort time p = .011, while in CG all variables do not have significant differences. The Independent T-test found that there was a significant difference between EG and CG with a significance value of p &lt; .05. This research concludes that the rotation play training model with HIIT Protocol has a positive effect on the anaerobic endurance of amateur futsal players.

Prediction of the fatigue life in a textured AZ31 Mg alloy as a function of orientation using fatigue indicator parameters

Computational homogenization was used to simulate the mechanical response of a textured AZ31Mg alloy subjected to fully-reversed cyclic deformation. The behavior of each grain in the polycrystal followed a phenomenological crystal plasticity model that considered different deformation mechanisms, namely pyramidal, basal, and prismatic slip, as well as twinning and detwinning. It also accounted for both kinematic and isotropic hardening effects. The crystal plasticity model's parameters were adjusted to replicate the cyclic stress-strain curves along three different orientations (rolling direction, normal direction and at 45° between the rolling and normal directions) at different cyclic strain semi-amplitudes. Three different fatigue indicator parameters were calculated from the simulations, based on the accumulated plastic shear strain in one stabilized fatigue cycle from basal slip and pyramidal slip, and from the shear strain accommodated by twinning/de-twinning during one fatigue cycle. The predictions of the fatigue life based on the fatigue indicator parameters were compared with the experimental results for the three orientations. It was found that the most accurate prediction was obtained by using the fatigue indicator parameter associated with twinning/de-twinning. Thus, it is concluded that fatigue cracks nucleated at twin boundaries control the fatigue life of textured Mg alloys.

Endurance training and hydroxyurea have synergistic effects on muscle function and energetics in sickle cell disease mice

Sickle cell disease (SCD) is an hemoglobinopathy resulting in the production of an abnormal Hb (HbS) which can polymerize in deoxygenated conditions, leading to the sickling of red blood cells (RBC). These alterations can decrease the oxygen-carrying capacity leading to impaired function and energetics of skeletal muscle. Any strategy which could reverse the corresponding defects could be of interest. In SCD, endurance training is known to improve multiples muscle properties which restores patient's exercise capacity but present reduced effects in anemic patients. Hydroxyurea (HU) can increase fetal hemoglobin production which can reduce anemia in patients. The present study was conducted to determine whether HU can improve the effects of endurance training to improve muscle function and energetics. Twenty SCD Townes mice have been trained for 8 weeks with (n = 11) or without (n = 9) HU. SCD mice muscle function and energetics were analyzed during a standardized rest-exercise-recovery protocol, using Phosphorus-31 Magnetic resonance spectroscopy (31P-MRS) and transcutaneous stimulation. The combination of training and HU specifically decreased fatigue index and PCr consumption while muscle oxidative capacity was improved. These results illustrate the potential synergistic effects of endurance training and HU on muscle function and energetics in sickle cell disease.

Investigation of Some Biomotoric Characteristics of Young German and Turkish Football Players

This research aimed to examine the biomotoric characteristics of Turkish and German young football players living in Germany. 32 football players participated in the research. Repetitive sprint test, agility test, vertical jump test and Sanding long jump test were applied to the football players. The physical and performance characteristics of the research group were analyzed using descriptive statistics and Mann Whitney U test. The results showed that there was a significant difference between the total times of the repeated sprint test and the total times of the repeated sprint test. There was no significant difference between the biomotoric characteristics between the groups, except for repeated 3-4-5 sprints and total times. Turkish football players completed the repetitive sprint test in a shorter time than German football players, but there was no difference in their fatigue index. This result seems meaningful considering that Turkish football players live in Germany, grow up in Germany, have similar environmental conditions, train similarly and play in the same league.

Influence of sexual maturation on anaerobic performance of male adolescent wrestlers

This study aimed to examine the impact of sexual maturation on the anaerobic performance of male adolescent wrestlers. Methods: We included a sample of 29 freestyle and Greco-Roman wrestlers from various clubs in Barinas, Venezuela. Their physical characteristics were as follows (mean ± SD): age, 14.99 ± 1.83 years; body mass, 54.68 ± 16.80 kg; height, 161.06 ± 12.78 cm; body fat, 12.09 ± 4.11%; body mass index (BMI), 20.58 ± 3.79 kg/m2; and training experience, 3.66 ± 2.27 years. Sexual maturation was evaluated using Tanner's criteria, while anaerobic performance was assessed with the 30-second Wingate test for both lower and upper body. Results: There were moderate to strong significant correlations between maturation development and both peak power (PP) and average power (AP) — for both absolute and relative measures — for the lower and upper body. The fatigue index (%FI) for the lower body did not show any correlation with maturation development or with the pubescent and postpubescent maturation categories. Conversely, the %FI for the upper body demonstrated a significant moderate correlation with maturation development and with the postpubescent maturation category. Additionally, a strong significant correlation was observed between the pubescent maturation category and both PP and AP (absolute and relative) for the lower body. A moderate correlation was found between the postpubescent category and PP (absolute) for the upper body. PP (absolute) and AP (relative) for the upper body had a moderate correlation with the pubescent maturation category, while the postpubescent category showed a strong correlation with PP (absolute), AP (absolute), and AP (relative). Conclusion: The stages of sexual maturation significantly influence the anaerobic capacity of adolescent wrestlers, potentially affecting their training adaptations for peak performance. Future research should explore the physiological responses to training protocols tailored to specific stages of maturation.

The Effects of Load, Crank Position, and Sex on the Biomechanics and Performance during an Upper Body Wingate Anaerobic Test.

The upper body Wingate Anaerobic Test (WAnT) is a 30-s maximal effort sprint against a set load (percentage of body mass). However, there is no consensus on the optimal load and no differential values for males and females, even when there are well-studied anatomical and physiological differences in muscle mass for the upper body. Our goal was to describe the effects of load, sex, and crank position on the kinetics, kinematics, and performance of the upper body WAnT. Eighteen participants (9 females) performed three WAnTs at 3%, 4%, and 5% of body mass. Arm crank forces, 2D kinematics, and performance variables were recorded during each WAnT. Our results showed an increase of ~49% effective force, ~36% peak power, ~5° neck flexion, and ~30° shoulder flexion from 3% to 5% load ( P < 0.05). Mean power and anaerobic capacity decreased by 15%, with no changes in fatigue index ( P < 0.05). The positions of higher force efficiency were at 12 and 6 o'clock. The least force efficiency occurred at 3 o'clock ( P < 0.05). Sex differences showed that males produced 97% more effective force and 109% greater mean power than females, with 11.7% more force efficiency ( P < 0.001). Males had 16° more head/neck flexion than females, and females had greater elbow joint variability with 17° more wrist extension at higher loads. Males cycled ~32% faster at 3% versus 5% WAnT load with a 65% higher angular velocity than females. Grip strength, maximal voluntary isometric contraction, mass, and height positively correlated with peak and mean power ( P < 0.001). In conclusion, load, sex, and crank position have a significant impact on performance of the WAnT. These factors should be considered when developing and implementing an upper body WAnT.

Using digital technologies for correction in the health condition process for IT specialists

Computers have swiftly integrated into people's daily lives, and their utilization continues to surge. The role of an IT support specialist encompasses expertise in network analysis, system administration, information security and assurance, IT audits, database administration, and web administration. The overarching objective is to cultivate a professionally adept and competitive specialist, whose attributes are shaped not only by professional aptitude but also by their personal lifestyle. Pursuing a career in IT necessitates adherence to several criteria, including possessing relevant education, intellectual acumen, teamwork capabilities, self-educational proficiency, a commitment to skill enhancement, and the ability to work autonomously. It is evident that the significance of this industry is growing each year. It is crucial to highlight that, without the implementation of occupational health and safety regulations, there is a substantial risk of a considerable decline in health protection, potentially leading to irreversible impacts on the overall functioning of the body. Adopting a healthy lif estyle involves establishing a self-designed system that safeguards an individual from risks encountered in an active life. To address this, we have developed a sequence of exercises aimed at providing psychological and physical relief for IT workers. The objective is to safeguard the health of employees in this category, incorporating exercises such as tapping biologically active zones, "Crane wings," and "Snake rings." The experimentally verified complex of measures designed for mental and physical relief for IT workers has demonstrated its effectiveness. Additionally, the execution of the exercise routine results in the alignment of morning and evening indicators, indicating an overall improvement in well-being and stable psycho-emotional state. The acquired results highlight a considerable decrease in fatigue indicators and the normalization of mood after completing the exercise routine.

Applicability of Ratings of Perceived Exertion as a Measure of Subjective Fatigue in First Responders: An Exploratory Study

Introduction: Many researchers use Ratings of Perceived Exertion (RPE) as an indicator of subjective fatigue. Recent findings suggest that energy and fatigue are two distinct unipolar moods. Methods: Eleven first responders (FR) participated in a 90-minute strenuous exercise battery where they ended the protocol by completing a graded VO2max test where they were asked to perform until volitional fatigue, measured through RPE. Subjective feelings of mental energy (ME) and fatigue (MF) and physical energy (PE) and fatigue (PF) were measured before the beginning of the protocol and right after. Data was not normally distributed and presented in median and interquartile ranges. Spearman correlation coefficients were calculated for RPE, post mood state, and changes in mood states. Results: Participants’ self-reported RPE at the conclusion of the VO2max test was 18.27 [18.00,19.00]. Post PE (r=-0.012, p=0.97), PF (r=-0.036, p=0.92), ME (r=-0.13, p=0.69), and MF (r=0.43, p=0.19) displayed insignificant correlations with RPE. Similarly, insignificant correlations were observed between changes in PE (r=0.26, p=0.44), PF (r=0.46, p=0.15), ME (r=0.35, p=0.30), MF (r=-0.43, p=0.19), and RPE. Five participants reported an increase in feelings of PE (15.00 [13.00,19.00]) and seven participants reported lower feelings of PF (-12.00 [-19.50,-8.00]) post assessment. Seven participants reported improvements in ME (22.00 [8.00,68.00]) and three reported a reduction in MF (-13.00 [-27.00, -7.00]). Conclusions: Our findings suggests that self-reported RPE may not be a reliable measure of subjective fatigue in FR populations during acute strenuous exercise. Further our findings support previous work that ME, MF, PE, and PF are four distinct unipolar moods, and researchers seeking to assess fatigue in FR should use RPE with caution as it seems to be a measure of subjective perception of exercise intensity instead of a true measure of subjective fatigue.

A unified expression for estimating Poisson’s ratio from a hinged–hinged beam with a use for abnormality detection

Cycle fatigue weakens a structure. Poisson’s ratio is a sensitive indicator of cycle fatigue. The amount of fatigue is proportional to the severity of an abnormality, such as a crack, delamination or other imperfection. Our prior work confirms that direct estimates of Poisson’s ratio by Cornu’s method must be identical for all antinodes of a mode shape of a homogeneous, thin, hinged–hinged beam. Therefore, if a direct estimate at any antinode was found to be significantly different from the other estimates at the other antinodes, then that would simultaneously indicate fatigue and identify the location of the abnormality. We use simulations of Besselograms and apply Cornu’s method to directly estimate Poisson’s ratio at all antinodes of a beam. We transform finite element simulations of the out-of-plane bending displacements of mode shapes by simulating time-average scanning digital holography. We show that amount of disagreement between the direct estimation Poisson’s ratio and the true value of Poisson’s ratio depends on the ratio of the distance between nodes of a mode shape divided by the width of the beam. We call this distance between the nodes of a mode shape the ‘Span’. We then define a unified expression for predicting the simulated direct estimate given the true value of Poisson’s ratio and the Span-to-Width ratio. Next, we invert the unified expression, which enables us to use the Span-to-Width ratio and simulated direct estimates of Poisson’s ratio as the independent variables to compute the adjusted value of Poisson’s ratio. We find that our inverse expression makes it possible to obtain an estimate of Poisson’s ratio that is within ±2% of the true value for thin hinged–hinged beams and plates that have a Span-to-Width ratio greater than 1. We also find that if the material is known to have a Poisson’s ratio greater than zero, which can be assessed by our previous statement, then we can extend our confidence to Span-to-Width ratios greater than 0.1. That was the lower limit of our testing. Finally, we show how to use direct estimates of Poisson’s ratio to statistically detect and localize an abnormality along a hinged–hinged plate or beam. We believe that our combination of Cornu’s method and time-averaging could eventually offer the ability to directly estimate Poisson’s ratio from hinged–hinged beams and plates as well as to unambiguously monitor cycle fatigue for changes in effective material properties, predict time-to-failure, and do so without contact.

Juçara (Euterpe edulis Martius) improves time-to-exhaustion cycling performance and increased reduced glutathione: a randomized, placebo-controlled, crossover, and triple-blind study.

To examine the effects of 7-days juçara powder (JP) intake on oxidative stress biomarkers and endurance and sprint cycling performances. In a randomized, placebo-controlled, crossover, and triple-blind study, 20 male trained cyclists were assigned to intake 10g of JP (240mg anthocyanins) or placebo (PLA) for 7 days and performed a cycling time-to-exhaustion (TTE). A 5s cycling sprint was performed before and after the cycling TTE. Blood oxidative stress biomarkers and lactate concentration where evaluated 1h before (T-1), immediately after (T0), and 1h after (T1) the cycling TTE. The mean duration time for the cycling TTE was 8.4±6.0% (63±17s) longer in the JP condition (JP: 751±283s) compared to PLA (688±266s) (P<0.019). Two-way repeated measures Analysis of variance showed an increase in the JP condition for reduced glutathione (GSH) (P=0.049) at T0 (P=0.039) and T1 (P=0.029) compared to PLA with a moderate effect size at T0 (d=0.61) and T1 (d=0.57). Blood lactate levels increased over time in both conditions (P≤0.001). No differences were observed for the post-TTE sprint fatigue index, total phenols, protein carbonyls, and glutathione peroxidase activity. Seven-day intake of JP improved cycling endurance performance and increased GSH levels but had no effect on lactate and cycling sprint-induced fatigue.