Individuals lack the ability to accurately detect emotional piloerection.

Piloerection (e.g., goosebumps) is an essential thermoregulatory and social signaling mechanism in non-human animals. Although humans also experience piloerection-often being perceived as an indicator of profound emotional experiences-its comparatively less effective role in thermoregulation and communication might influence our capacity to monitor its occurrence. We present three studies (total N = 617) demonstrating participants' general inability to detect their own piloerection events and their lack of awareness that piloerection occurs with a similar frequency on multiple anatomical locations. Self-reported goosebumps were more frequent than observed piloerection. However, only 31.8% of self-reports coincided with observable piloerection, a bias unrelated to piloerection intensity, anatomical location, heart-rate variability, or interoceptive awareness. We also discovered a self-report bias for the forearm, contradicting the observation that piloerection occurs with equal frequency on multiple anatomical locations. Finally, there was low correspondence between self-reports of being "emotionally moved" and observed piloerection. These counterintuitive findings not only highlight a disconnect between an obvious physiological response and our capacity for self-monitoring, but they underscore a fascinating divergence between human and non-human species. Although piloerection is vital in non-human organisms, the connection between piloerection and psychological experience in humans may be less significant than previously assumed, possibly due to its diminished evolutionary relevance.

Temporal progression of Alzheimer's disease in brains and intestines of transgenic mice.

The amyloid beta (Aß) peptide is associated with the neurodegenerative and inflammatory changes in brains affected by Alzheimer's disease (AD). We hypothesized that the enteric nervous system also produces Aß in an intestinal component of disease. To test this idea, we compared C57BL/6 wild-type (WT) male and female mice to two models of Alzheimer's disease, amyloid precursor protein (APP)/presenilin 1 (PS1) mice and amyloid precursor protein NL-G-F (AppNL-G-F) mice, at 3, 6, and 12 months of age. Brain Aß plaque deposition in AppNL-G-F mice preceded that in the APP/PS1 mice, observable by 3 months. Three-month-old female AppNL-G-F mice had decreased intestinal motility compared with WT and APP/PS1 mice. However, 3-month-old female APP/PS1 mice demonstrated increased intestinal permeability compared with WT and AppNL-G-F mice. Both sexes of APP/PS1 and AppNL-G-F mice demonstrated increased colon lipocalin 2 mRNA and insoluble Aß 1-42 levels at 3 months. These data demonstrate an unrecognized enteric aspect of disease in 2 different mouse models correlating with the earliest brain changes.

Effects of ingestion of a commercially available thermogenic dietary supplement on resting energy expenditure, mood state and cardiovascular measures.

BACKGROUND: Increasing metabolism is a primary focus of many commercially available dietary supplements marketed to support weight management. Caffeine (e.g. anhydrous and herbal) and green tea are key ingredients in such products, augmenting resting energy expenditure (REE) and improving reported mood states (alertness, fatigue, focus, etc.). The purpose of this study was to evaluate the effects of a thermogenic dietary supplement (DBX) on REE, respiratory exchange ratio (RER), reported measures of alertness, focus, energy, concentration, fatigue, and hunger, as well as the general safety of the product based on electrocardiogram (ECG) and hemodynamic responses in habitual caffeine consumers. METHODS: Six male and six female subjects (mean ± SD; 22.50 ± 3.22 years; 76.94 ± 14.78 kg; 22.7 ± 9.5% body fat), physically active (≥12 months), and moderate habitual caffeine consumers (<200 mg/day) received either two capsules of DBX containing 340 mg of total caffeine plus green tea extract, yerba mate extract, carnitine tartrate and other active ingredients or a placebo (PLC) in a double-blinded, crossover design. Heart rate (HR), blood pressure (BP), REE, RER and perceived mood states were measured at baseline and then hourly for four hours after ingesting either treatment. RESULTS: Resting energy expenditure was significantly increased at all four time points and significant increases were determined for perceived alertness (p = 0.026) and focus (p = 0.05) at hour 1 and for energy at 1 and 2 hours after treatment for the DBX group (p = 0.008 and p = 0.017, respectively). Additionally, perceived fatigue was decreased at the hour 1 assessment (p = 0.010). No significant differences were seen between DBX and placebo for hunger, anxiety, HR, BP, ECG patterns or RER. CONCLUSIONS: The results of this investigation support that the proprietary blend of this thermogenic aid is capable of increasing REE for four hours post-ingestion while supporting increased focus, alertness, and energy as well as decreasing fatigue without promoting anxiety or causing significant changes in HR, BP, or ECG measurements in habitual caffeine consumers.

The effects of tournament preparation on anthropometric and sport-specific performance measures in youth judo athletes.

The purpose of this study was to characterize the adaptations imposed by 4 weeks of precompetition judo training in youth athletes. It was hypothesized that anthropometric and sport-specific performance would improve during the preparation for a junior national championship event. Twenty youth athletes (mean ± SD; chronological age: 13.1 ± 3.2 years; training age: 5.3 ± 3.5 years; judo experience: 7.8 ± 2.5 hours per week) completed pretesting and posttesting procedures. Child (12 years old; n = 8) and adolescent (13 years old; n = 12) groups were evaluated to determine the anthropometric and sport-specific performance changes caused by 4 weeks of judo training conducted in preparation for the junior national championships. The child group showed an increase in flexibility (11.5%), and the adolescent group showed a decrease in skinfold thickness (-12.2%); increased jumping power (26.7%), force (7.7%), and velocity (19.0%); and improved judo-specific ability (-5.9%), as measured by the Special Judo Fitness Test (SJFT) index. Additionally, the SJFT index for all the study participants was shown to be inversely correlated to handgrip strength (r = -0.681), rope pull performance (r = -0.545), and jump height (r = -0.503). These results support the use of preparatory judo training in the improvement of anthropometric and sport-specific measures in adolescent athletes. Furthermore, the outcomes from this study provide direction for coaches and trainers in their efforts to impact physical performance and judo skills in children and adolescents through precompetition training.

Predicting maximal aerobic capacity (VO2max) from the critical velocity test in female collegiate rowers.

The objective of this study was to examine the relationship between the critical velocity (CV) test and maximal oxygen consumption (VO2max) and develop a regression equation to predict VO2max based on the CV test in female collegiate rowers. Thirty-five female (mean ± SD; age, 19.38 ± 1.3 years; height, 170.27 ± 6.07 cm; body mass, 69.58 ± 0.3 1 kg) collegiate rowers performed 2 incremental VO2max tests to volitional exhaustion on a Concept II Model D rowing ergometer to determine VO2max. After a 72-hour rest period, each rower completed 4 time trials at varying distances for the determination of CV and anaerobic rowing capacity (ARC). A positive correlation was observed between CV and absolute VO2max (r = 0.775, p < 0.001) and ARC and absolute VO2max (r = 0.414, p = 0.040). Based on the significant correlation analysis, a linear regression equation was developed to predict the absolute VO2max from CV and ARC (absolute VO2max = 1.579[CV] + 0.008[ARC] - 3.838; standard error of the estimate [SEE] = 0.192 L·min(-1)). Cross validation analyses were performed using an independent sample of 10 rowers. There was no significant difference between the mean predicted VO2max (3.02 L·min(-1)) and the observed VO2max (3.10 L·min(-1)). The constant error, SEE and validity coefficient (r) were 0.076 L·min(-1), 0.144 L·min(-1), and 0.72, respectively. The total error value was 0.155 L·min(-1). The positive relationship between CV, ARC, and VO2max suggests that the CV test may be a practical alternative to measuring the maximal oxygen uptake in the absence of a metabolic cart. Additional studies are needed to validate the regression equation using a larger sample size and different populations (junior- and senior-level female rowers) and to determine the accuracy of the equation in tracking changes after a training intervention.

An alternative approach to the Army Physical Fitness Test two-mile run using critical velocity and isoperformance curves.

The purpose of this study was to evaluate the use of critical velocity (CV) and isoperformance curves as an alternative to the Army Physical Fitness Test (APFT) two-mile running test. Seventy-eight men and women (mean +/- SE; age: 22.1 +/- 0.34 years; VO2(MAX): 46.1 +/- 0.82 mL/kg/min) volunteered to participate in this study. A VO2(MAX) test and four treadmill running bouts to exhaustion at varying intensities were completed. The relationship between total distance and time-to-exhaustion was tracked for each exhaustive run to determine CV and anaerobic running capacity. A VO2(MAX) prediction equation (Coefficient of determination: 0.805; Standard error of the estimate: 3.2377 mL/kg/min) was developed using these variables. Isoperformance curves were constructed for men and women to correspond with two-mile run times from APFT standards. Individual CV and anaerobic running capacity values were plotted and compared to isoperformance curves for APFT 2-mile run scores. Fifty-four individuals were determined to receive passing scores from this assessment. Physiological profiles identified from this procedure can be used to assess specific aerobic or anaerobic training needs. With the use of time-to-exhaustion as opposed to a time-trial format used in the two-mile run test, pacing strategies may be limited. The combination of variables from the CV test and isoperformance curves provides an alternative to standardized time-trial testing.

The reliability of the intermittent critical velocity test and assessment of critical rest interval in men and women.

The purpose of this study was to examine the reliability of the intermittent critical velocity (ICV) test and assess critical rest interval (CRI) during repeated-sprint exercise. The ICV test is used to examine the linear relationship between total distance and time-to-exhaustion during interval exercise, yielding a repeatable, moderate-intensity parameter (ICV), a high-intensity exhaustive parameter (W'), and CRI. CRI is the theoretical rest period needed to complete a series of repeated bouts of exercise without fatigue. Twenty-four healthy college-aged men (mean ± SD; age 22.7 ± 2.9 years; weight 85.8 ± 15.3 kg; VO(2max) 50.7 ± 8.8 ml/kg/min) and women (mean ± SD; age 21.4 ± 2.3 years; weight 58.9 ± 5.2 kg; VO(2max) 46.4 ± 4.4 ml/kg/min) participants completed two ICV tests (T1 and T2), using 10 s repeated sprints to exhaustion during separate sessions of treadmill running. Linear regression was used to determine ICV and W', while CRI was calculated using the relationship between the number of intervals completed and a variant of ICV. Intraclass correlation coefficients (ICCs) for ICV, W', and CRI were 0.89 (T1 4.42 ± 0.55 m/s; T2 4.34 ± 0.67 m/s), 0.80 (T1 125.6 ± 62.7 m; T2 144.6 ± 65.4 m), and 0.59 (T1 23.9 ± 2.0 s; T2 24.5 ± 2.6 s), respectively. These moderate to high ICC values indicate reliable measurements between ICV trials. Additionally, the evaluation of CRI demonstrated the attainment of a steady-state heart rate (94% of maximum) during a separate session of repeated supramaximal treadmill sprints. The ICV test during treadmill running provides reliable ICV and W' measures, as well as an estimated recovery time via CRI for men and women.

Impact of testing strategy on expression of upper-body work capacity and one-repetition maximum prediction after resistance training in college-aged men and women.

The purpose of this study was to assess the effect of resistance training on upper-body muscular strength and the expression of work capacity and muscular endurance. In addition, a training-induced change in the relationship between muscular strength and endurance was assessed by testing changes in the accuracy of using endurance repetitions to predict 1 repetition maximum (1RM) bench press before and after training. College-aged men (n = 85) and women (n = 62) completed a 12-week linear periodization resistance training program. Before and after training, the subjects were assessed for 1RM and repetitions to fatigue (RTFs) with a submaximal load. After pretraining 1RM determination, the subjects were randomly assigned to perform RTFs at 65% 1RM (n = 74) or 90% 1RM (n = 73). Pretraining and posttraining RTFs were conducted at the same respective % 1RM. Work capacity was determined from repetition weight × RTF. After training, there was a significant increase in 1RM in both men (∼14%) and women (∼23%). Posttraining RTF was not different from pretraining RTF at 65 %1RM (18.2 ± 5.1 and 19.0 ± 6.0, respectively) but was significantly reduced in the 90% 1RM group (6.1 ± 3.6 vs. 4.5 ± 2.7, respectively). Likewise, there was a differential effect of training on the expression of work capacity, which increased in the 65 % 1RM group (123 ± 155 kg-reps) but decreased in the 90% 1RM group (-62 ± 208 kg-reps); the effect was independent of gender within each testing group. In conclusion, the changes in muscular strength associated with resistance training produced an increase in work capacity when tested with a 65 % 1RM load without a change in endurance. In contrast, both work capacity and endurance decreased when tested with 90% 1RM. Thus, the impact of strength training on work capacity and muscle endurance is specific to the load at which endurance testing is performed.

Critical velocity: a predictor of 2000-m rowing ergometer performance in NCAA D1 female collegiate rowers.

The aims of this study were to examine the use of the critical velocity test as a means of predicting 2000-m rowing ergometer performance in female collegiate rowers, and to study the relationship of selected physiological variables on performance times. Thirty-five female collegiate rowers (mean ± s: age 19.3 ± 1.3 years; height 1.70 ± 0.06 m; weight 69.5 ± 7.2 kg) volunteered to participate in the study. Rowers were divided into two categories based on rowing experience: varsity (more than 1 year collegiate experience) and novice (less than 1 year collegiate experience). All rowers performed two continuous graded maximal oxygen consumption tests (familiarization and baseline) to establish maximal oxygen uptake (VO(2max)), peak power output, and power output at ventilatory threshold. Rowers then completed a critical velocity test, consisting of four time-trials at various distances (400 m, 600 m, 800 m, and 1000 m) on two separate days, with 15 min rest between trials. Following the critical velocity test, rowers completed a 2000-m time-trial. Absolute VO(2max) was the strongest predictor of 2000-m performance (r = 0.923) in varsity rowers, with significant correlations also observed for peak power output and critical velocity (r = 0.866 and r = 0.856, respectively). In contrast, critical velocity was the strongest predictor of 2000-m performance in novice rowers (r = 0.733), explaining 54% of the variability in performance. These findings suggest the critical velocity test may be more appropriate for evaluating performance in novice rowers.

The determination of critical rest interval from the intermittent critical velocity test in club-level collegiate hockey and rugby players.

The intermittent critical velocity (ICV) test is used to quantify the relationship between velocity and time to exhaustion, yielding an aerobic parameter (ICV), an anaerobic parameter (anaerobic running capacity [ARC]), and critical rest interval (CRI). Critical rest interval is the theoretical rest period needed to maintain repeated bouts of exercise for an extended period of time without inducing fatigue during intermittent treadmill running. Fourteen collegiate, club-level male participants (mean ± SD; age: 21.4 ± 1.8 years; weight: 82.8 ± 5.9 kg; body fat: 11.8 ± 5.4%; and VO2max: 51.2 ± 2.8 ml · kg · min), primarily hockey and rugby players, completed the ICV test, using 15-second repeated sprints to exhaustion during separate sessions of treadmill running at varying supramaximal intensities. The time and total distance for each running session were used to determine ICV and ARC via linear regression. The CRI was calculated using the relationship between total distance during the ICV test and the number of intervals completed. Mean ICV and ARC (± SD) values were calculated as 4.80 ± 0.3 m · s and 154.1 ± 36 m, respectively. The mean ICV values were significantly different from the mean peak velocity (± SD) (4.67 ± 0.17 m · s) achieved during the VO2max test (p = 0.011). The CRI was calculated as mean ± SD: 33.9 ± 1.9 seconds. Body fat percentage measured by air displacement plethysmography (BOD POD®; r = -0.649; p = 0.012), lean body mass (r = -0.556; p = 0.039), fat mass (r = -0.634; p = 0.015), body weight (r = -0.669; p = 0.006), and relative VO2max (r = 0.562; p = 0.036) were significantly correlated with ICV. The ARC (r = 0.804; p = 0.001) and velocity at ventilatory threshold (r = -0.630; p = 0.016) were significantly correlated with CRI. The ability to quantify CRI, an additional variable derived from the ICV test, provides a possible measure that can be used in the prescription and evaluation of training methods.

International Society of Sports Nutrition position stand: meal frequency.

Position Statement: Admittedly, research to date examining the physiological effects of meal frequency in humans is somewhat limited. More specifically, data that has specifically examined the impact of meal frequency on body composition, training adaptations, and performance in physically active individuals and athletes is scant. Until more research is available in the physically active and athletic populations, definitive conclusions cannot be made. However, within the confines of the current scientific literature, we assert that:1. Increasing meal frequency does not appear to favorably change body composition in sedentary populations.2. If protein levels are adequate, increasing meal frequency during periods of hypoenergetic dieting may preserve lean body mass in athletic populations.3. Increased meal frequency appears to have a positive effect on various blood markers of health, particularly LDL cholesterol, total cholesterol, and insulin.4. Increased meal frequency does not appear to significantly enhance diet induced thermogenesis, total energy expenditure or resting metabolic rate.5. Increasing meal frequency appears to help decrease hunger and improve appetite control.The following literature review has been prepared by the authors in support of the aforementioned position statement.

Determination of aerobic and anaerobic performance: a methodological consideration.

This study was designed to compare critical velocity (CV) and anaerobic running capacity (ARC) estimates using the criterion method of four runs with two and three combination bouts to reduce the time and energy demands of the subjects. Twenty-eight men and women (mean ± SD; age = 21.9 ± 3.0 years; stature = 171.7 ± 9.7 cm; body mass = 69.7 ± 13.4 kg) performed an incremental test to exhaustion to determine peak velocity (PV) at maximal oxygen consumption (VO(2)max). Four high-speed runs to exhaustion were conducted on separate days with 110% PV, 90% PV (day 1), 100% PV and 105% PV (day 2). The distances achieved were plotted over the times to exhaustion. Linear regression was used to determine the slopes (CV) and y-intercepts (ARC) using four velocities and the other ten possible velocity combinations. Two runs to exhaustion, at 90% PV and 110% PV, produced similar CV and ARC results to the standard four bouts (ICC = 0.995, SEM = 0.298). Three velocities at 90% PV, 100% PV and 110% PV also resulted in no differences from the criterion method (ICC = 0.999, SEM = 0.075). These results suggest that CV and ARC can be estimated from two velocities, but to ensure a linear relationship, three velocities are recommended.

Mechanical scale and load cell underwater weighing: a comparison of simultaneous measurements and the reliability of methods.

Both load cell and mechanical scale-based hydrostatic weighing (HW) systems are used for the measurement of underwater weight. However, there has been no direct comparison of the 2 methods. The purpose of the current investigation was to simultaneously compare a load cell and mechanical scale for use in HW. Twenty-seven men and women (mean ± SD, age: 22 ± 2 years) participated in the 2-day investigation. Each subject completed 2 HW assessments 24 hours apart. Single-day comparisons of all trials for both days revealed no significant difference between the mechanical scale and the load cell (mean difference < 0.016 kg, p > 0.05). True underwater weight values were not significantly different between methods for either days (mean difference < 0.014 kg, p > 0.05) and accounted for a mean difference in percent fat (%FAT) of <0.108%. The 95% limits of agreement indicated a maximum difference between methods of 0.53% FAT. Both methods produced similar reliability SEM values (mechanical SEM < 0.72%FAT, load cell SEM < 0.75%FAT). In conclusion, there was no difference between mechanical scale and load cell measurements of underwater weights and the added precision of the load cell only marginally (<0.16%FAT) improved day-to-day reliability. Either a mechanical scale or load cell can be used for HW with similar accuracy and reliability in young adults with a body mass index of 18.7-34.4 (5-25%FAT).

The development of physiological profiles and identification of training needs in NCAA female collegiate rowers using isoperformance curves.

The purpose of this study was to propose a systematic method for the identification of training strategies and team selection using isoperformance curves. Rowing is a sport that relies on both aerobic and anaerobic energy contributions during a standard 2,000 m competition. The critical velocity model combines both aerobic (critical velocity, CV) and anaerobic (anaerobic rowing capacity, ARC) parameters in a single two-dimensional graphic display. The concept of isoperformance curves, a series of linear equations corresponding to minimum performance standards, allows for an objective overview of a large group of athletes of varying talent. The purpose of this study was to develop physiological profiles from the CV test, and to evaluate results with isoperformance curves to identify training strategies for collegiate rowers. Thirty-five female collegiate rowers completed four time trials over various distances (400, 600, 800, and 1,000 m). CV and ARC were calculated and compared between novice and varsity athletes. CV values for the varsity group were significantly higher than the novice group (P = 0.016). No significant differences were found between groups for ARC (P = 0.068). Mean and individual CV and ARC values were plotted on the x- and y-axes, respectively, and junior, collegiate, and elite isoperformance curves were developed using 2,000 m times from recent indoor rowing competitions. Stratification of athletes through isoperformance curves was used to identify specific training interventions (anaerobic and/or aerobic) needed to improve their 2,000 m performance. The information drawn from isoperformance curves and the parameters of the CV test can be used to provide an objective view of physiological capabilities and training needs on both an individual and team basis.

Physiological effects of caffeine, epigallocatechin-3-gallate, and exercise in overweight and obese women.

The aim of this study was to evaluate the combined effects of a 10-week exercise program with ingestion of caffeine and epigallocatechin-3-gallate (EGCG) on body composition, cardiovascular fitness, and strength in overweight and obese women. In a double-blind, placebo-controlled approach, overweight and obese women (n = 27) were randomly assigned to treatment groups with exercise (an active-supplementing group with exercise (EX-Act) and a placebo group with exercise (EX-PL)) or without exercise (an active-supplementing group without exercise (NEX-Act) and a placebo group without exercise (NEX-PL)). All participants consumed 1 drink per day for 10 weeks; EX-Act and EX-PL participated in a concurrent endurance and resistance training program. Changes in body composition were assessed using a 4-compartment model. Changes in muscle mass (MM) were evaluated using a DXA-derived appendicular lean-soft tissue equation. There was a significant time × treatment interaction for MM (p = 0.026) and total cholesterol (TC) (p = 0.047), and a significant time × training interaction for peak oxygen consumption (p = 0.046) and upper-body and lower-body strength (p < 0.05). Significant differences between the EX groups and NEX groups for percentage change in MM and peak oxygen consumption, and upper-body and lower-body strength, were revealed. Clinical markers for hepatic and renal function revealed no adverse effects. TC significantly decreased for the active-supplementing groups (EX-Act, NEX-Act). The current study suggests that implementing a caffeine-EGCG-containing drink prior to exercise may improve MM, fitness, and lipid profiles in overweight women.

The possible combinatory effects of acute consumption of caffeine, creatine, and amino acids on the improvement of anaerobic running performance in humans.

Preexercise nutritional investigations have recently become a popular avenue of examining the interaction of multiple ingredients on exercise and training methods. The critical velocity (CV) test is used to quantify the relationship between total running distance and time to exhaustion (TTE), yielding aerobic (CV) and anaerobic parameters (anaerobic running capacity [ARC]). The purpose of this study was to examine the hypothesis that a preexercise supplement containing caffeine, creatine, and amino acids (Game Time; Corr-Jen Laboratories Inc, Aurora, CO) would positively impact CV and ARC in college-aged men and women. In a single-blind crossover design, 10 participants consumed the preexercise supplement (ACT) or placebo (PL) before each testing session. Each participant completed runs to exhaustion on a treadmill at 110%, 90% (day 1), and 105% and 100% (day 2) of the peak velocity (PV) determined from a graded exercise test. The ACT elicited a 10.8% higher ARC (P = .02) compared with the PL, whereas no difference was found in CV (0.6%, P = .38). The TTE was greater for the ACT than the PL at 110% (ACT = 125.7 ± 9.6 seconds, PL = 117.3 ± 12.6 seconds), 105% (ACT = 156.9 ± 11.0 seconds, PL = 143.8 ± 12.9 seconds), and 100% PV (ACT = 185.7 ± 10.7 seconds, PL = 169.7 ± 12.8 seconds) (P = .01-.04); but there was no difference for the TTE at 90% PV (ACT = 353.5 ± 52.7 seconds, PL = 332.7 ± 54.0 seconds) (P = .08). These findings suggest that the acute ingestion of this preexercise supplement may be an effective strategy for improving anaerobic performance, but appears to have no effect on aerobic power.

Upper-body strength gains from different modes of resistance training in women who are underweight and women who are obese.

The purpose of this study was to determine the degree of upper-body strength gained by college women who are underweight and those who are obese using different modes of resistance training. Women who were underweight (UWW, n = 93, weight = 49.3 ± 4.5 kg) and women who were obese (OBW, n = 73, weight = 94.0 ± 15.1 kg) were selected from a larger cohort based on body mass index (UWW ≤ 18.5 kg·m⁻²; OBW ≥ 30 kg·m⁻²). Subjects elected to train with either free weights (FW, n = 38), supine vertical bench press machine (n = 52) or seated horizontal bench press machine (n = 76) using similar linear periodization resistance training programs 3× per week for 12 weeks. Each participant was assessed for upper-body strength using FWs (general) and machine weight (specific) 1 repetition maximum bench press before and after training. Increases in general and mode-specific strength were significantly greater for OBW (5.2 ± 5.1 and 9.6 ± 5.1 kg, respectively) than for UWW (3.5 ± 4.1 and 7.2 ± 5.2 kg, respectively). General strength gains were not significantly different among the training modes. Mode-specific gains were significantly greater (p < 0.05) than general strength gains for all groups. In conclusion, various resistance training modes may produce comparable increases in general strength but will register greater gains if measured using the specific mode employed for training, regardless of the weight category of the individual.

Reproducibility and validity of bioimpedance spectroscopy for tracking changes in total body water: implications for repeated measurements.

Bioimpedance spectroscopy (BIS) has been used to track changes in total body water (TBW). Accurate TBW estimations can be influenced by both methodological and biological factors. One methodological variation that contributes to BIS TBW errors is the electrode placement. The purpose of the present study was to compare the reproducibility and validity of fixed-distance electrode placements (5 cm) with the standard single-site electrode placements. Twenty-nine subjects (fifteen men and fourteen women) participated in the reproducibility study, while sixty-nine subjects (thirty-three men and thirty-six women) participated in the validity study. The reproducibility study included two measurements that were taken 24 h apart, while the validity study consisted of a 12-week exercise intervention with measurements taken at weeks 1 and 12. TBW was estimated using BIS and 2H techniques. Reproducibility results indicated that fixed-distance electrodes reduced the day-to-day standard error of the measurement in men (from 1·13 to 0·81 litres) but not in women (0·47 litres). sem values were lower for women than for men, suggesting that BIS TBW estimates are sex dependent. Validity results produced similar accurate findings (mean difference < 0·21 litres). However, fixed-distance electrodes improved delta TBW errors (mean difference improvements>0·04 litres in men, women, and men and women combined). When tracking changes in TBW, fixed-distance electrodes may reduce reproducibility errors and allow for smaller changes to be detected. However, the reduction of reproducibility errors may be greater for men than for women. Therefore, reproducibility calculations should be based on the sex of the sample population.

The effects of creatine loading and gender on anaerobic running capacity.

Creatine (Cr) loading consists of short-term, high-dosage Cr supplementation and has been shown to increase intramuscular total Cr content. Increases in body weight (BW) have been shown to result from Cr loading, with differences by gender, and increased BW may impact weight-bearing exercise. The critical velocity (CV) test is used to quantify the relationship between total running distance and time to exhaustion. The CV test provides the variable, anaerobic running capacity (ARC), which is an estimate of the anaerobic energy reserves in muscle. The purpose of this study was to examine the effects of gender and Cr loading on ARC. Fifty moderately trained men and women volunteered to participate in this randomized, double-blinded, placebo (PL)-controlled, repeated-measures study. After a familiarization session, a 3-day testing procedure was conducted. A maximal oxygen consumption test VO(2)max) on a treadmill was performed on day 1 to establish the maximum velocity (Vmax) at VO(2)max and to record BW. Days 2 and 3 involved treadmill running at varying percentages of Vmax. Participants were randomly assigned to either the Cr or PL group and received 20 packets of the Cr supplement (1 packet = 5 g Cr citrate, 18 g dextrose) or 20 packets of the PL (1 packet = 18 g dextrose). After consuming 4 packets daily for 5 consecutive days, the 3-day testing procedure was repeated. The male Cr loading group exhibited a 23% higher (p = 0.003) ARC compared to the PL group. Nonsignificant BW increases were found for the Cr groups. These findings suggest that Cr loading may be an effective strategy for improving ARC in men, but not in women, and revealed only nonsignificant increases in BW. Creatine loading may be used before competition by athletes to provide improvements in high-intensity, short-duration activities.