Heart Rate Variability Threshold Evaluation During Arm and Leg Cycling

Background: The Heart Rate Variability Threshold (HRVT) is a point of deflection in heart rate variability assessed during incremental exercise to exhaustion. This threshold is thought to represent a shift in the autonomic balance. Purpose: The purpose of this study was to evaluate (HRVT) during arm (AC) and leg cycling (LC). Methods: There were twenty-three participants (age: 23.3±4.7 years; height: 168.6±7.5 cm; weight 66.8±8.9 kg). Participants completed two graded exercise tests, one for AC and one for LC on different days. They wore a heart rate monitor which recorded R-R intervals. The test performed was a graded exercise test to exhaustion (GXT) using a ramp protocol. The root mean square of successive differences between normal heartbeats (RMSSD) of the R-R intervals during the GXT was calculated using specialized software. A time-varying moving average (64 second window and 3 second shift) was used. A piecewise fitting function consisting of two linear functions was used to detect time and RMSSD at HRVT. The time (as percentage of the total time to exhaustion) at which HRVT occurred was also calculated. Log transformation was performed in case the normality assumption was violated. A paired t-test was run for the outcomes of interest. Mean and standard deviations were reported and an alpha value of p Results: Log transformation was performed on the RMSSD and percentage at HRVT. There was no significant difference in time at HRVT (p=0.36) between AC (4.2 ± .1.0 minutes) and LC (3.9 ± 1.6 minutes) or percentage at threshold (p=0.85) between AC (49.3 ± 11.9%) and LC (50.4 ± 20.1%). There was also no significant difference in RMSSD at HRVT (p=0.93) between arm (1.3 ± 0.36 ms) and leg cycling (1.3 ± 0.54 ms). Conclusion: Time, RMSSD, and percentage at HRVT were not different between exercise modes. Autonomic balance, as measured by heart rate variability threshold, does not seem to be influenced by exercise modality

A SYSTEMATIC APPROACH FOR THE CLASSIFICATION OF AGE-RELATED MUSCLE LOSS AND ELDERLY OBESITY USING FIELD-BASED TESTING METHODS AND ISOPERFORMANCE CURVES

The process of aging causes a wide variety of physiological changes that can manifest in the form of differing body composition phenotypes. A systematic approach to body composition classification and the subsequent selection of appropriate interventions is needed for community-based health care and fitness specialists. The primary purpose of this investigation was to determine body composition classification using field-based testing measurements in healthy elderly men and women. The use of isoperformance curves is presented as a method for this determination. Baseline values from 107 healthy Caucasian men and women over the age of 65 years old who participated in a separate longitudinal study were used for this investigation. Age, height, weight, body mass index (BMI), and handgrip strength were recorded on an individual basis. Relative skeletal muscle index (RSMI) and body fat percentage (FAT%) were determined by dual-energy X-ray absorptiometry (DXA) for each participant. Sarcopenia cut-off values for RSMI of 7.26 kg·m-2 for men and 5.45 kg·m-2 for women and elderly obesity cut-off values for FAT% of 27% for men and 38% for women were used. Individuals above the RSMI cut-off and below the FAT% cut-off were classified in the normal phenotype category, while individuals below the RSMI cut-off and above the FAT% cut-off were classified in the sarcopenic-obese phenotype category. The relationship between age and BMI, handgrip strength, RSMI, and FAT% was characterized using linear regression. Prevalence values for body composition phenotypes from actual DXA-based criteria and predicted RSMI and FAT% were evaluated. Using the DXA criterion values for RSMI and FAT%, 34 individuals (32% of the sample) were classified as normal, 50 individuals (47% of the sample) were classified as obese, 10 individuals (9% of the sample) were classified as sarcopenic, and 13 individuals were classified as sarcopenic obese. Prediction equations for RSMI and FAT% from BMI and handgrip strength values were developed using multiple regression analysis. The prediction equations were validated using double cross-validation. The final regression equation developed to predict FAT% from BMI and handgrip strength resulted in a strong relationship (adjusted R2=0.741) to DXA values with a low standard error of the estimate (SEE=3.9937%). The final regression equation developed to predict RSMI from the field-based testing measures also resulted in a strong relationship (adjusted R2=0.841) to DXA values with a low standard error of the estimate (SEE=0.5437 kg·m-2). Using the prediction values for FAT% and RSMI, 30 individuals (28% of the sample) were classified as normal, 58 individuals (54% of the sample) were classified as obese, 17 individuals (16% of the sample) were classified as sarcopenic, and 2 individuals (2% of the sample) were classified as sarcopenic obese. Subsequently, isoperformance curves were used to aid in the classification and evaluation of sarcopenia, obesity, and sarcopenic obesity in elderly individuals by graphically representing the relationship between BMI and handgrip strength with the aforementioned clinical phenotype classification criteria. The final goal of this investigation was to produce easily understood charts that can be used by personal trainers, nutrition specialists, and/or health professionals. The charts could be used in the classification of individuals into these phenotype categories in an inexpensive and non-invasive manner. Future research should be undertaken that enhances the current findings by increasing the sample size and developing tailored interventions for each body composition category

Accumulated Oxygen Deficit During Arm Cranking in Hypoxia: A Bayesian Perspective and Methodological Considerations

International Journal of Exercise Science 14(3): 1090-1098, 2021. The purpose of this investigation was to observe the effects of normobaric hypoxia on accumulated oxygen deficit (AOD) with evaluation using both Bayesian and Frequentist analyses. Eighteen recreationally active men performed a graded exercise test (GXT) in normobaric normoxia (N; FiO2~20%) and normobaric hypoxia (H; FiO2~14%) to determine peak power output (PPO). Time to exhaustion trials were later conducted at 110% and 120% PPO under both N, and H. AOD and %AN (% anaerobic energy contribution) were calculated in three conditions: N, H, and H using the N regression equation (HN). Bayesian repeated measures ANOVA revealed differences in AOD and %AN between regression equations while Frequentist Repeated measures ANOVA revealed non-significant differences for AOD (p = .148) and %AN (p = .150). Using predicted oxygen consumption extrapolated from a normoxic environment during exercise in hypoxia may lead to overestimation of AOD and %AN with a Bayesian approach and contrasting results using frequentist statistics

Lepton Flavour Violation in a Class of Lopsided SO(10) Models

A class of predictive SO(10) grand unified theories with highly asymmetric mass matrices, known as lopsided textures, has been developed to accommodate the observed mixing in the neutrino sector. The model class effectively determines the rate for charged lepton flavour violation, and in particular the branching ratio for $\mu -> e \gamma$, assuming that the supersymmetric GUT breaks directly to the constrained minimal supersymmetric standard model (CMSSM). We find that in light of the combined constraints on the CMSSM parameters from direct searches and from the WMAP satellite observations, the resulting predicted rate for $\mu -> e \gamma$ in this model class can be within the current experimental bounds for low $\tan \beta$, but that the next generation of $\mu -> e \gamma$ experiments would effectively rule out this model class if LFV is not detected.Comment: 23 page

Improving muscle strength and size: the importance of training volume, intensity, and status

Increases in muscle size and strength are influenced by the mechanical and metabolic stresses imposed by resistance training. Mechanical stress is induced by the use of high-intensity training and it is believed it activates a larger percentage of muscle fibers. Conversely, metabolic stress is generated by high training volumes with moderate intensities using short rest intervals. This training paradigm results in greater fatigue and potentially stimulates a greater anabolic hormone response to exercise. Although evidence exists for both strategies, it still remains inconclusive whether one training paradigm is more advantageous than the other regarding muscle hypertrophy development. In untrained adults, the novelty of most resistance training programs may be sufficient to promote hypertrophy and strength gains, whereas greater training intensity may be more beneficial for trained adults. However, the body of well-designed research in this advanced population is limited. Therefore, the purpose of this brief review is to discuss the merits and limitations of the current evidence

High-Risk Environmental Conditions Attenuates Performance Efficiency Index in NCAA DI Female Soccer Players

International Journal of Exercise Science 15(6): 442-454, 2022. The purpose of this study was to evaluate the effects of environmental conditions on running performance and performance efficiency index (Effindex). Performance data recorded using Polar Team Pro sensors from eight collegiate female soccer players in nine matches were analyzed during the 2019 competitive season. Effindex and running performance, including total distance covered (TDREL) and distance covered in five speed thresholds relative to minutes played, were examined for indications of fatigue with respect to environmental conditions, including ambient temperature and relative humidity. Matches were separated into three groups based on environmental conditions: Low-Risk (n = 2 matches), Moderate-Risk (n = 3 matches), or High-Risk (n = 4 matches). Speed thresholds were grouped as follows: walking (WALKREL), jogging (JOGREL), low-speed running (LSRREL), high-speed running (HSRREL), and sprinting (SPRINTREL). A significant effect was observed for TDREL in all environmental conditions (η2 = 0.614). TDREL was significantly lower in the High-Risk (p = 0.002; 95.32 ± 12.04 m/min) and Moderate-Risk conditions (p = 0.004; 94.85 ± 9.94 m/min) when compared to Low-Risk (105.61 ± 9.95 m/min). WALKREL (p = 0.005), JOGREL (p = 0.005) LSRREL (p = 0.001), HSRREL (p = 0.035), SPRINTREL (p = 0.017), and Effindex (p = 0.0004) were significantly greater in Low-Risk conditions when compared to Moderate-Risk conditions. WALKREL (p = 0.005), HSRREL (p = 0.029), SPRINTREL (p = 0.005), and Effindex (p = 0.0004) were significantly greater in Low-Risk conditions when compared to High-Risk conditions. High-Risk environmental conditions may result in adverse performance in female collegiate soccer players

Effects of a long-term adapted judo program on the health-related physical fitness of children with ASD

[Abstract] Physical fitness is one of the most important physical and mental health aspects for children with Autism Spectrum Disorder (ASD). This study aimed to test the effects of a long-term adapted judo program on the health-related physical fitness of children with ASD. The participants were recruited from various associations of families and schools for children with special needs. Twenty-one children were assigned to an experimental group and nineteen to a control group. The experimental group participated in a six-month adapted judo program consisting of 90 min of practice each week. Health-related physical fitness was measured using the indicators obtained from the ALPHA-fitness battery, the estimated VO2max and the waist/height ratio0.5. Changes within and between groups were analyzed using linear mixed models for repeated measures designs and test-retest reliability of tests requiring a maximum score using the Intraclass Correlation Coefficient (ICC). A judo program tailored for children with ASD can improve the cardio-metabolic health and cardiorespiratory fitness of its participants. The problems involved with administering physical aptitude tests that involve maximum effort or performance in children with ASD cast serious doubts on the reproducibility of their results

Improving motor skills and psychosocial behaviors in children with autism spectrum disorder through an adapted judo program

[Abstract] Introduction: This study aimed to investigate the long-term effects of an adapted judo program on the motor skills and psychosocial abilities of children with Autism Spectrum Disorder (ASD). Methods: All participants had been diagnosed with ASD and were assessed twice, one time at the start of the intervention and again 6 months later, with the Test of Gross Motor Development (TGMD-3) and the Gilliam Autism Rating Scale-Third Edition (GARS-3). A one-way repeated measures MANOVA was carried out in order to evaluate these assessments, and a mediation analysis was done to determine the relationship between them. Results: The experimental group significantly improved (p < 0.05) from the pre-test to the post-test for several subtests of the TGMD-3 and the GARS-3. Conclusion: The study shows that participation in an adapted judo program clearly helps to improve the motor skills and psychosocial behaviors of children with ASD

Gravitino constraints on models of neutrino masses and leptogenesis

In the supersymmetric extensions of the standard model, neutrino masses and leptogenesis requires existence of new particles. We point out that if these particles with lepton number violating interactions have standard model gauge interactions, then they may not be created after reheating because of the gravitino problem. This will rule out all existing models of neutrino masses and leptogenesis, except the one with right-handed singlet neutrinos.Comment: 12 pages latex file with one postscript figur

Effects of resistance training on classic and specific bioelectrical impedance vector analysis in elderly women

Raw bioelectrical impedance analysis (BIA) data [resistance (R); reactance (Xc)] through bioelectrical impedance vector analysis (BIVA) and phase angle (PhA) have been used to evaluate cellular function and hydration status. The purpose of this investigation was to examine the effects of resistance training (RT) on classic and specific BIVA in elderly women. Twenty women (mean ± SD; age: 71.9 ± 6.9 years; BMI: 24.5 ± 3.0 kg m(-2)) completed a 6-month RT program. Whole-body, single-frequency BIA, body geometry, and leg strength (5RM) measures were completed at baseline (t0), 3 months (t3), and 6 months (t6). The mean impedance vector displacements were compared using Hotelling's T(2) test to evaluate changes in R and Xc relative to height (R/ht; Xc/ht) or body volume (Rsp; Xcsp) estimated from the arms, legs, and trunk. 5RM, PhA, and BIVA variables were compared using ANOVA. PhA improved at t6 (p < 0.01), while 5RM improved at t3 and t6 (p < 0.01). Using classic BIVA, 6 months (T(2) = 31.6; p < 0.01), but not 3 months of RT (T(2) = 4.5; p = 0.20), resulted in significant vector migration. Using specific BIVA, 6 months (T(2) = 24.4; p < 0.01), but not 3 months of RT (T(2) = 5.5; p = 0.10), also resulted in significant vector migration. 5RM was correlated to both PhA (r = 0.48-56) and Xcsp (r = 0.45-53) at all time points. Vector displacements were likely the result of improved cellular integrity (Xcsp) and cellular health (PhA)