Graded Treadmill Exercise Test Research Articles

Interferential Electrical Stimulation Versus Pulsed Electro-Magnetic Field in Management of Intermittent Claudication

Background: Intermittent claudication is the occurrence of leg pain, aching, cramping, or fatigue triggered by walking and relieved by rest. It's a chronic disabling condition and the first symptom of peripheral arterial disease (PAD). Objective: This study was designed to compare between the therapeutic efficacy of Interferential electrical stimulation and pulsed electromagnetic field (PEMF) in management of intermittent claudication (IC). Subjects and methods: Forty five patients suffering from intermittent claudication due to atherosclerosis (Fontain stage II PAD) and randomly were assigned into three equal groups. Group “A” included 15 patients received 30 min of pulsed electromagnetic field in addition to heel raise exercise and calf stretch exercise and their medical treatment, group “B” included 15 patients received 20 min of interferential electrical stimulation in addition to heel raise exercise and calf stretch exercise and group “C” (control group) that included 15 patients received their medical treatment only. Ankle brachial pressure index, graded treadmill exercise testing to determine absolute claudication distance (ACD), Peak walking time (PWT) and walking impairment questionnaire (distance score, speed score, symptoms impairment score) were recorded pre and post the two months period for all groups. Results: All measured parameters were significantly improved in all groups with the greatest improvement was in group (A) and the least improvement was in group (C) except for ankle brachial index that was changed significantly in group (A) only. Conclusion: PEMF could be an effective vascular rehabilitation modality for improving walking efficiency and functional capacity in patients with intermittent claudication. It significantly increases the blood flow in peripheral arteries and so on can delay the complications of intermittent claudication.

Post-exercise Cardiac Autonomic Modulation: Comparison Between Triathlon And High-intensity Functional Training Athletes.

PURPOSE: To verify if athletes submitted to volume overload display differences in the cardiac autonomic function throughout the post-exercise recovery phase comparatively to athletes submitted to resistance overload. METHODS: 30 men were divided into three equal groups (p>0,05): non-athlete group (n=10 30.8±3.0 year, BMI: 24.6±2.7 kg/m2), high-intensity functional training athletes (n=10, 31.4±2.9 year, BMI: 31.4±2.2 kg/m2), and triathlon athletes (n=10, 31.2±2.8 year, BMI: 23.1±1.8 kg/m2). Participants underwent a maximal graded treadmill exercise test followed by a five-minute of active recovery protocol (2,4km/h 2,5%). During the post-exercise recovery phase, a valid R-R intervals series were recorded (5min) using a valid and reliable heart rate monitor. The data were processed off-line using the Kubios HRV - Heart Rate Variability Software. A Kruskal-Wallis test was used to determine differences in SD1 and SD2 indices between all groups. The SD1 and SD2 indices were used to assess the degree of parasympathetic reactivation and global cardiac modulation, respectively over the recovery phase. Heart rate variability, by means, SD1 and SD2 indexes of Poincaré Plot were recorded during the 30s; 1stmin; 3rdmin and 5thmin of recovery to evaluate the cardiac autonomic function (CAF). RESULTS: No significant differences were found in parasympathetic and global cardiac modulation between groups, There were no difference between 3 groups in SD1-30s (2.66-3.15; p = 0.29), SD1-1st min (2.52-3.24; p = 0.23), SD1-3rd min (2.87-3.72; p = 0.58), SD1-5th min (3.08-4.29; p = 0.44), SD2-30s (2.22-2.88; p = 0.21), SD2-1st min (2.57-2.92; p = 0.39), SD2-3rd min (4.36-5.78; p = 0.58), SD2-5th min (5.34-6.79; p = 0.53). Possibly, the magnitude of differences is small, which warrants a larger sample size than used in our study to detect statistical differences. CONCLUSIONS: In our study, no significant differences in parasympathetic and global cardiac modulation were found between groups. These initials results show that individuals submitted to resistance and volume overload training have similar abilities of the autonomic branches (sympathetic and parasympathetic) on the modulation of the heart throughout the post-exercise recovery.

Energetic Profile in Forehand Loop Drive Practice with Well-Trained, Young Table Tennis Players.

The forehand loop drive is one of the primary attacking techniques in table tennis and is practiced at a large volume during training. The aim of this study was to investigate the energetic profile of the high-repetition forehand loop drive practice in table tennis. Twenty-six well-trained, young table tennis players performed a treadmill graded exercise test to determine their peak oxygen uptake as a measure of overall cardiorespiratory fitness and an incremental table tennis stroke test with 3-min intervals during the forehand loop drive with a ball-throwing robot at a frequency of 35 to 85 strokes∙min−1. Pulmonary and blood parameters were measured and analyzed with a portable spirometry system and a blood lactate analyzer. Energy contributions were calculated from aerobic, anaerobic lactic, and anaerobic alactic pathways for each stroke frequency. Energy cost was defined as the amount of energy expended above resting levels for one stroke. Repeated-measures analyses of variance (ANOVA) with the stroke frequency (35,45,55,65,75, or 85 strokes/min−1) as a within-subject factor were performed for the dependent variables. A Power regression was performed for the energy cost as a function of the stroke frequency. Findings demonstrated a function of Y = 91.566·x−0.601 where Y is the energy cost and x is the stroke frequency, R2 = 0.9538. The energy cost decreased at higher stroke frequencies. The energy contributions from aerobic, anaerobic lactic, and anaerobic alactic pathways at each stroke frequency ranged from 79.4%–85.2%, 0.6%–2.1%, and 12.9%–20.0%, respectively. In conclusion, the energy cost of the forehand loop drive decreased at higher stroke frequencies. The high-repetition forehand loop drive practice was aerobic dominant and the anaerobic alactic system played a vital role.

Critical speed and finite distance capacity: norms for athletic and non-athletic groups.

Two parameters in particular span both health and performance; critical speed (CS) and finite distance capacity (D'). The purpose of the present study was to: (1) classify performance norms, (2) distinguish athletic from non-athletic individuals using the 3-min all-out test (3MT) for running, and (3) introduce a deterministic model highlighting the relationship between variables of the 3MT. Athletic (n = 43) and non-athletic (n = 25) individuals participated in the study. All participants completed a treadmill graded exercise test (GXT) with verification bout and a 3MT on an outdoor sprinting track. Meaningful differences between non-athletic and athletic individuals (denoted by mean difference scores, p value and Cohen's d with 95% confidence intervals) were evident for CS (- 0.74ms-1, p < 0.001, d = - 1.41 [1.97, - 0.87]), exponential growth time constant ([Formula: see text]; 2.75s, p < 0.001, d = - 1.29 [- 1.45, - 0.42]), time to maximal speed ([Formula: see text]; - 2.80s, p < 0.001, d = - 0.98 [- 1.51, - 0.47]), maximal speed ([Formula: see text]; - 1.36ms-1, p < 0.001, d = - 1.56 [- 2.13, - 1.01]), gas exchange threshold (GET; - 5.62mlkg-1min-1, p < 0.001, d = - 0.97 [- 1.50, - 0.45]), distance covered in the first minute (1st min; - 81.69m, p < 0.001, d = - 1.91 [- 2.52, - 1.33]), distance covered in the second minute (2nd min; - 52.02m, p < 0.001, d = - 1.71 [- 2.30, - 1.15]) and maximal distance (- 153.78m, p < 0.001, d = - 1.27 [- 1.82, - 0.74]). The correlation coefficient between key physiological and performance variables are shown in the form of a deterministic model created from the data derived from the 3MT. Coaches and clinicians may benefit from the use of normative data to potentially identify exceptional or irregular occurrences in 3MT performances.

Acute leptin response after high intensity interval and moderate intensity continuous runs

The possible direct role of exercise intensity and duration on leptin concentrations is conflicting. The aim of this study was to evaluate the acute effects of high intensity interval (HIIE) and moderate intensity continuous (MICE) exercise on plasma leptin response. Seven young volunteers underwent three tests: 1) a treadmill graded exercise test to identify running peak velocity (PV); 2) HIIE: 5 × 2 min work bouts at 90% of PV, interspersed by 2 min of passive recovery and; 3) MICE: 30 min at 70 % of PV. Blood samples were drawn for the assays of leptin before and 30 minutes after HIIE and MICE. A 2-way repeated measures ANOVA showed a significant main effect of time [F(1,6) =17,52; p=0,006], no significant effect of condition (type of exercise) (F(1,6) = 0,16; p = 0,68) and no significant interaction (condition × time) (F(1,6)= 0,48, p=0,51). Leptin decreased 30 min after HIIE (t= 2,95, p=0,025) and MICE (t=4,18; p=0,005). There was no difference between the HIIE and MICE conditions immediately after exercise (t=0,90; p=0,40). After HIIE and MICE, leptin decreased in the same magnitude. It appears that both exercise modalities result in physical stress which is sufficient to improve short-term leptin sensibility.

Seasonal changes in wildland firefighter fitness and body composition

Hiking with a pack is the highest-intensity task that wildland firefighters (WLFFs) perform during sustained activities related to wildland fire suppression. Firefighters perform this and other tasks together as a crew; this provides a unique model to evaluate select physical and physiological changes in members of working crews over a fire season during extended operations. The objective of this study was to evaluate changes in peak aerobic fitness (VO2peak), sustainable aerobic fitness at the ventilatory threshold (VO2vt) and body composition over a 5-month wildland fire season. WLFFs from four crews (55 males, 10 females) participated in a maximal graded exercise treadmill test and body composition evaluation pre- and post season. VO2peak values and variance did not change across the fire season (pre=3.96±0.65, post=3.96±0.69Lmin−1, not significant). VO2vt average decreased slightly while variance decreased greatly within each crew (pre=37.5±7.0, post=35.4±2.3mLkg−1 min−1, P&amp;lt;0.05). There was an improvement in VO2vt in initially less-fit WLFFs and a VO2vt decrease in initially more-fit WLFFs. WLFFs lost fat mass (−1.56±−1.06kg, P&amp;lt;0.01) and fat-free mass (−0.38±−1.24kg, P&amp;lt;0.05). Post-season VO2vt values were the same as the higher range of the documented metabolic cost of uphill load carriage and reveal a unique group adaptation to extended physical demands.

Physical Fitness in Patients With Oligoarticular and Polyarticular Juvenile Idiopathic Arthritis Diagnosed in the Era of Biologics: A Controlled Cross-Sectional Study.

To perform a comprehensive evaluation of and identify correlates for physical fitness in consecutive patients with juvenile idiopathic arthritis (JIA) who have been diagnosed in the era of biologics and to compare the results with those obtained in healthy controls. The study cohort included 60 patients with JIA (50 girls) ages 10-16 years and 60 age- and sex-matched controls. The JIA group included 30 patients with persistent oligoarticular JIA and 30 patients with extended oligoarticular or polyarticular disease. Measures of physical fitness included cardiorespiratory fitness (CRF) by peak oxygen uptake (Vo2peak ) during a continuous graded treadmill exercise test, muscle strength by isokinetic and isometric knee and hand grip evaluations, and bone mineral density (BMD) and body composition by dual-energy x-ray absorptiometry. Physical activity was assessed by accelerometry. Forty-two percent of the patients were being treated with biologic drugs. Patients with JIA demonstrated lower muscle strength and total body BMD compared to controls, but there were no differences in CRF and body composition. Physical fitness was comparable between the persistent oligoarticular and extended oligoarticular/polyarticular-JIA groups. In patients with JIA, we identified associations between higher vigorous physical activity and higher CRF and muscle strength, but did not find any association between physical fitness and disease variables. In this cohort of patients with JIA, we found suboptimal muscle strength and BMD compared to controls, but no differences in CRF and body composition. Vigorous physical activities appeared important for optimizing muscle strength and CRF in patients with JIA; the importance of such activities should be highlighted in patient education.

Individualized Relative-Intensity Physical Activity Accelerometer Cut Points.

Physical activity (PA) intensity is expressed as either absolute or relative intensity. Absolute intensity refers to the energy required to perform an activity. Relative intensity refers to a level of effort that takes into account how hard an individual is working relative to their maximum capacity. We sought to develop methods for obtaining individualized relative-intensity accelerometer cut points using data from a maximal graded exercise treadmill test (GXT) so that each individual has their own cut point. A total of 2363 men and women 38 to 50 yr old from the CARDIA fitness study wore ActiGraph 7164 accelerometers during a maximal GXT and for seven consecutive days in 2005-2006. Using mixed-effects regression models, we regressed accelerometer counts on heart rate as a percentage of maximum (%HRmax) and on RPE. Based on these two models, we obtained a moderate-intensity (%HRmax = 64% or RPE = 12) count cut point that is specific to each participant. We applied these subject-specific cut points to the available CARDIA accelerometer data. Using RPE, the mean moderate-intensity accelerometer cut point was 4004 (SD = 1120) counts per minute. On average, cut points were higher for men (4189 counts per minute) versus women (3865 counts per minute) and were higher for Whites (4088 counts per minute) versus African Americans (3896 counts per minute). Cut points were correlated with body mass index (rho = -0.11) and GXT duration (rho = 0.33). Mean daily minutes of absolute- and relative-intensity moderate to vigorous PA were 34.1 (SD = 31.1) min·d and 9.1 (SD = 18.2) min·d, respectively. RPE cut points were higher than those based on %HRmax. This is likely due to some participants ending the GXT before achieving their HRmax. Accelerometer-based relative-intensity PA may be a useful measure of intensity relative to maximal capacity.

Benefits of dietary supplements on the physical fitness of German Shepherd dogs during a drug detection training course.

A high standard of physical fitness is an essential characteristic of drug detection dogs because it affects not only their ability to sustain high activity levels but also their attention and olfaction efficiency. Nutritional supplements could improve physical fitness by modulating energy metabolism, oxidative processes, and perceived fatigue. The aim of this study was to investigate the physiological and biochemical changes induced by submaximal exercise on drug detection dogs (German Shepherd breed) and to assess whether a dietary supplement improves their physical fitness. During a drug detection dog training course, seven dogs were fed with a basal diet (Control Group) for three-month period, while a further seven dogs were fed with a basal diet as well as a daily nutritional supplement containing branched-chain and limiting amino acids, carnitine, vitamins, and octacosanol (Treatment Group). At the end of this period, individual physical fitness was assessed by making each subject take a graded treadmill exercise test. A human heart rate monitor system was used to record the dog’s heart rate (HR) during the treadmill exercise and the subsequent recovery period. The parameters related to HR were analysed using nonparametric statistics. Blood samples were collected before starting the nutritional supplement treatment, before and after the treadmill exercise and following recovery. Linear mixed models were used. The dietary supplements accelerated HR recovery, as demonstrated by the lower HR after recovery (P<0.05) and Time constants of HR decay (P<0.05), and by the higher Absolute HR Recovered (P<0.05) recorded in the Treatment group compared with the Control dogs. The supplemented dogs showed the lowest concentrations of creatine kinase (CK; P<0.001), aspartate aminotransferase (AST, P<0.05) and non-esterified fatty acids (NEFA; P<0.01) suggesting a reduction in muscle damage and improvement of energy metabolism. These data suggest that this combined supplement can significantly enhance the physical fitness of drug detection dogs.

The Influence of AlterG Treadmill Training on Cardiorespiratory Performance in Cross Country Runners

Running on an AlterG® Treadmill (AGT) at reduced bodyweight allows runners to aerobically train with reduced orthopedic stress. However, to maintain the training stimulus, the speed must be increased if heart rate (HR) response is to match overground running. This allows one to run at faster speeds for longer durations, without increasing impact forces or HR intensity beyond typical training. Yet it is unknown how this speed intensity chronically influences cardiorespiratory performance. PURPOSE: Investigate the effect of an AGT training program on cardiorespiratory performance. METHODS: As an offseason supplement, 19 healthy uninjured high school boy cross country runners replaced 2 overground running sessions/week for 6 weeks with AGT runs at 80-85% of bodyweight. Speed was increased to elicit a HR intensity and distance/time consistent with each runner’s mile pace for that day. Pulmonary gas exchange and HR data were collected during treadmill graded exercise tests (GXT) at pre and post AGT training program. Paired t-test were used to assess pre-post changes in cardiorespiratory and HR variables from the GXT (p≤0.05). RESULTS: The mean speed of AGT runs was 9.0 ± 0.5 mph at a mean distance of 4.2 ± 0.6 miles. The mean of the fastest speed for each runner was 9.8 ± 0.6 mph (range 8.6-11.4) at a mean run time of 27.6 ± 8.4 min. (range 16-40 minutes). HR [180 ± 9 vs. 167 ± 10 bpm] significantly decreased while oxygen uptake remained unchanged [46.6 ± 3.6 vs. 47.0 ± 3.2 ml/kg/min] at the anaerobic threshold (AT) post AGT training. However, peak oxygen uptake [60.8 ± 6.4 vs. 62.7 ± 5.0 ml/kg/min], peak minute ventilation [124.7 ± 22.6 vs. 132.2 ± 24.9 L/min], and peak respiratory frequency [61 ± 10 vs. 64 ± 11 breaths/min] significantly improved post AGT training, while peak HR remained unchanged [196 ± 20 vs. 192 ± 12 bpm]. CONCLUSION: AGT training with reduced bodyweight at faster speeds had little influence on cardiorespiratory performance variables occurring at lower levels of intensity (AT). However, all peak cardiorespiratory performance variables at higher levels of intensity improved, likely due to training at faster than normal speeds. This would benefit runners by allowing training to occur with reduced orthopedic loading at typical HR intensities, and yet still concurrently improve peak cardiorespiratory performance.

1526-P: Delayed Heart Rate Recovery after Exercise as a Risk Factor of Incident Metabolic Syndrome: A Retrospective Cohort Study

Background: There have been several cross-sectional studies reporting that delayed heart rate recovery (HRR) after exercise is associated with the development of the metabolic syndrome (MetS). However, there have been few longitudinal studies. We evaluated the longitudinal association of delayed HRR following a graded exercise treadmill test (GTX) with the incident MetS including metabolic parameters as adjusting factors. Methods: A retrospective longitudinal cohort study of participants without MetS, diabetes or cardiovascular diseases has been designed. HRR was calculated as peak heart rate minus heart rate after a 1-minute rest (HRR 1), heart rate after a 2-minute rest (HRR 2), and heart rate after a 3-minute rest (HRR 3). To investigate the association between HRR and incident MetS, multivariate Cox proportional hazards analysis was performed. Results: During 9,683 person-years of follow-up between 2006 and 2012, there were 676 (31.2%) incident cases of the MetS. After adjustment for age, sex, smoking status, baseline heart rate, peak heart rate, peak oxygen uptake, hs-CRP, waist circumference, systolic blood pressure, TG, LDL-C, HDL-C, fasting plasma glucose, HOMA-IR, and HbA1c, the hazard ratios (HR) [95% confidence interval (CI)] of incident MetS comparing the first and second tertiles to the third tertile of HRR 3 were 1.492 (1.146-1.943) and 1.277 (1.004-1.624) (P for trend = 0.003). As a continuous variable, after full adjustments, the HR (95% CI) of incident MetS associated with each 1-second decrease in HRR3 was 1.015 (1.005 -1.026) (P = 0.004). Conclusion: Delayed HRR 3 after exercise could predict incident MetS, even after adjusting for metabolic parameters. However, HRR 1 and HRR 2 have not shown the statistic significance. Disclosure T. Yu: None. S. Jin: None. K. Hur: None. J. Bae: None. J. Jee: None. J. Kim: None. M. Lee: None.

Supporting Physical Health Of Black Male Faculty Through A Wellness-integrated Professional Development Program: FIT Leaders

PURPOSE: An intervention strategy examining the integration of professional development and wellness for black male faculty at an R1 university was conducted. The intervention was directed at supporting the retention and academic promotion of black male faculty through minimizing the impact of culturally relevant physical (i.e., hypertension, obesity) and cognitive (i.e. John-Henryism, social isolation, discrimination, etc.) challenges. The implications on the physical health of the participants are presented here. METHOD: A 24-week intervention brought together black male faculty of differing ranks at a university fitness center twice per week. Each session included a 45 min trainer lead exercise session followed by a 30 min semi-guided discussion on culturally relevant professional development topics. A series of assessments implemented in a pre-/post-structure around the intervention included cardiovascular measures including central aortic pressure, brachial blood pressure (BP) and carotid-femoral pulse wave velocity (cf-pwv) measured via the Sphygmocor Xcel Device, body composition via BodPod, strength and cardiorespiratory fitness via graded exercise treadmill test. Pre-post analyses using paired T-tests were performed using STATA 13.4. RESULTS: Among 9 participants the mean age was 40.4 +/- 4.1 years. Cardiovascular measures improved including Aortic Systolic Pressure 123+/-11 vs 117+/-12 mmHg, p=0.007; Brachial systolic BP 136+/-10 vs 128+/-12mmHg, p=0.002; Brachial diastolic BP 87+/-10 vs. 84+/-10, p=0.057; and Cf-pwv 8.3+/-1.4 vs. 6.9=+/-0.6 m/s (n=6, p=0.007). Adiposity measures improved including body mass index 29.6+/-5.0 vs. 29.0+/-4.9 kg/m2, p=0.014; waist circumference 96.6+/-11.8 vs. 93.4+/-12 cm, p<0.001; and body fat percentage 26.9+/-7.7 vs. 23.4+/-7.6%, p=0.005. Max chest press improved from 174.4+/-52.1 vs. 191.4+/-45.9 lbs, p=0.008. There were no improvements in cardiorespiratory fitness, highest VO2max 37.1+/-7.4 vs. 37.5+/-6.9 ml/kg/min (n=7), p=0.801. CONCLUSION: Changes in the physical health of participants indicate that this intervention shows promise for supporting the physical wellness of black male faculty in parallel with culturally relevant leadership support.

Effect of Treadmill Protocol on Attainment of VO2max Criteria in Collegiate Women Athletes

When performing the same test protocol, athletes from sports of differing metabolic demands may vary in the achievement of physiological criteria that are indicative of attaining maximal oxygen consumption (VO2max). PURPOSE: To examine whether the attainment of VO2max criteria differs in two sports with differing metabolic demands as a result of the graded exercise treadmill test (GXT) protocol used. METHODS: Twenty-nine National Collegiate Athletic Association Division 1 women athletes (basketball (WBB): n=11; lacrosse (WLAX): n=18) completed a continuous GXT to volitional fatigue. Speed increased following each 1-minute stage with a 1% constant grade. VO2peak indicated the highest VO2 value reached during a single test, while VO2max indicated the subject’s functional limit was reached. The criteria to attain VO2max were: VO2 plateau of <0.15 L/min with an increase in the last two workloads; maximum heart rate (HRmax) within 10 bpm of age-predicted heart rate max; respiratory exchange ratio (RER)>1.10; rating of perceived exertion (RPE, 1-10 scale)>8; blood lactate (LAC) collected 5-min post-test >8mmol/L. The attainment > 3 of 5 criteria was required for VO2max. Independent t-tests were used for comparison of values between teams, and chi-squared test was used for comparison of criteria attainment. Alpha level was set at p<0.05. RESULTS: Relative VO2peak values did not differ between teams (WBB: 55.3 ± 8.1; WLAX: 53.8 ± 5.4 mL∙kg-1∙min-1). The percent of athletes that met each of the five criteria were: plateau (WBB: 55%, WLAX: 56%), HRmax (WBB: 27%, WLAX: 39%), RER (WBB: 0%, WLAX: 17%), RPE (WBB: 55%, WLAX: 44%), LAC (WBB: 100%, WLAX: 83%). More WLAX attained VO2peak than VO2max (55% vs. 45%). WBB was evenly distributed between VO2peak (50%) and VO2max (50%). There was no statistical difference between WBB and WLAX in VO2max or the number of athletes from each team who met each individual criterion. Significant differences between teams were observed for LAC (WBB 13.3 ± 1.7, WLAX 10.3 ± 2.3 mmol/L; p=0.001) and RER (WBB 0.96 ± 0.05, WLAX 1.04 ± 0.09; p=0.002). CONCLUSION: These findings suggest physiological responses to a fixed VO2max protocol may vary between sport teams of different metabolic demands. Consideration should be given to such variations when selecting test protocols and interpreting results.

Effects Of Honest And Dishonest Pre-exercise Placebo Ingestion On Vo2Peak And Isometric Handgrip Performance

Pre-exercise consumption of placebo has been shown to improve resistance and endurance exercise performance. However, the effects of placebo ingestion on graded exercise test performance have not been widely reported in the literature. PURPOSE: The purpose of this study was to examine the effects of honest (subjects were told they were consuming placebo) or dishonest (subjects were told they were consuming a pre-workout supplement) placebo ingestion on VO2peak values determined during a maximal treadmill graded exercise test. A secondary purpose of this study was to examine the effects of placebo consumption on isometric handgrip performance. We hypothesized that pre-exercise ingestion of both placebo conditions would result in increased VO2peak and handgrip performance compared to control. METHODS: 28 males (178.4 ± 6.94 cm, 83.3 ± 14.8 kg, 22.6 ± 2.3 yrs.) and 13 females (166.4 ± 8.49 cm, 73.6 ± 20 kg, 26.4 ± 11 yrs.) participated in this study. In a randomized, cross-over design, subjects performed treadmill VO2peak and isometric handgrip testing after consumption of honest placebo (HP) or dishonest placebo (DP). In addition, a third baseline trial (CON) was performed to establish performance values that were unaffected by a perceived placebo effect due to supplementation. All outcomes were assessed for normality using the Shapiro-Wilks test. When assumptions of normality were violated, log transformations were computed. However, transformations did not improve model assumptions. Therefore, non-transformed data is reported. One-way ANOVAs were used to analyze VO2peak and handgrip strength data across conditions. Alpha was set at 0.05 prior to all analyses. RESULTS: Significant between-groups differences (p < 0.05) were not detected for relative VO2peak (CON = 46.2 ± 9.3 mL/kg/min; HP = 46.7 ± 10 mL/kg/min; DP = 46.6 ± 9.6 mL/kg/min) or for maximal handgrip strength (CON = 43 ± 9.6 kg; HP = 44.1 ± 12.4 kg; DP = 43.4 ± 12.1 kg). CONCLUSION: Administration of honest or dishonest placebo immediately prior to VO2peak and handgrip testing had no effect on performance compared to control. The VO2peak and isometric handgrip tests were found to be robust exercise tests not significantly influenced by perceived pre-workout supplement consumption.

Physiological Performance Measures as Indicators of CrossFit® Performance.

CrossFit® began as another exercise program to improve physical fitness and has rapidly grown into the “sport of fitness”. However, little is understood as to the physiological indicators that determine CrossFit® sport performance. The purpose of this study was to determine which physiological performance measure was the greatest indicator of CrossFit® workout performance. Male (n = 12) and female (n = 5) participants successfully completed a treadmill graded exercise test to measure maximal oxygen uptake (VO2max), a 3-minute all-out running test (3MT) to determine critical speed (CS) and the finite capacity for running speeds above CS (D′), a Wingate anaerobic test (WAnT) to assess anaerobic peak and mean power, the CrossFit® total to measure total body strength, as well as the CrossFit® benchmark workouts: Fran, Grace, and Nancy. It was hypothesized that CS and total body strength would be the greatest indicators of CrossFit® performance. Pearson’s r correlations were used to determine the relationship of benchmark performance data and the physiological performance measures. For each benchmark-dependent variable, a stepwise linear regression was created using significant correlative data. For the workout Fran, back squat strength explained 42% of the variance. VO2max explained 68% of the variance for the workout Nancy. Lastly, anaerobic peak power explained 57% of the variance for performance on the CrossFit® total. In conclusion, results demonstrated select physiological performance variables may be used to predict CrossFit® workout performance.

The Role of Muscle Perfusion in the Age-Associated Decline of Mitochondrial Function in Healthy Individuals.

Maximum oxidative capacity of skeletal muscle measured by in vivo phosphorus magnetic resonance spectroscopy (31P-MRS) declines with age, and negatively affects whole-body aerobic capacity. However, it remains unclear whether the loss of oxidative capacity is caused by reduced volume and function of mitochondria or limited substrate availability secondary to impaired muscle perfusion. Therefore, we sought to elucidate the role of muscle perfusion on the age-related decline of muscle oxidative capacity and ultimately whole-body aerobic capacity. Muscle oxidative capacity was assessed by 31P-MRS post-exercise phosphocreatine recovery time (τPCr), with higher τPCr reflecting lower oxidative capacity, in 75 healthy participants (48 men, 22–89 years) of the Genetic and Epigenetic Signatures of Translational Aging Laboratory Testing study. Muscle perfusion was characterized as an index of blood volume at rest using a customized diffusion-weighted MRI technique and analysis method developed in our laboratory. Aerobic capacity (peak-VO2) was also measured during a graded treadmill exercise test in the same visit. Muscle oxidative capacity, peak-VO2, and resting muscle perfusion were significantly lower at older ages independent of sex, race, and body mass index (BMI). τPCr was significantly associated with resting muscle perfusion independent of age, sex, race, and BMI (p-value = 0.004, β = −0.34). τPCr was also a significant independent predictor of peak-VO2 and, in a mediation analysis, significantly attenuated the association between muscle perfusion and peak-VO2 (34% reduction for β in perfusion). These findings suggest that the age-associated decline in muscle oxidative capacity is partly due to impaired muscle perfusion and not mitochondrial dysfunction alone. Furthermore, our findings show that part of the decline in whole-body aerobic capacity observed with aging is also due to reduced microvascular blood volume at rest, representing a basal capacity of the microvascular system, which is mediated by muscle oxidative capacity. This finding suggests potential benefit of interventions that target an overall increase in muscle perfusion for the restoration of energetic capacity and mitochondrial function with aging.

Acute Supplementation with Molecular Hydrogen Benefits Submaximal Exercise Indices. Randomized, Double-Blinded, Placebo-Controlled Crossover Pilot Study.

BackgroundClinical studies have reported hydrogen-rich water (HRW) to have therapeutic and ergogenic effects. The aim of this study was to determine the effect of acute supplementation with HRW on exercise performance as measured by VO2, respiratory exchange ratio (RER), heart rate (HR), and respiratory rate (RR).MethodsBaseline levels of all exercise indices were determined in nineteen (4 female, 23.4 ± 9.1 yr; 15 male, 30.5 ± 6.8 yr) healthy subjects using a graded treadmill exercise test to exhaustion. Each subject was examined two additional times in a randomized double-blinded, placebo-controlled crossover fashion. Subjects received either HRW or placebo, which was consumed the day before and the day of the testing. HRW was delivered using the hydrogen-producing tablets, DrinkHRW (5 mg of H2). All data was analyzed with SPSS using pairwise comparisons with Bonferroni adjustment.ResultsHRW supplementation did not influence maximal or minimal indices of exercise performance (VO2, RER, HR and RR) (p < 0.05). However, HRW significantly decreased average exercising RR and HR (p < 0.05). HRW decreased exercising HR during minutes 1–9 of the graded exercise test (121 ± 26 bpm) compared to placebo (126 ± 26 bpm) and baseline (124 ± 27 bpm) (p < 0.001) without substantially influencing VO2.ConclusionAcute supplementation of DrinkHRW tablets may benefit submaximal aerobic exercise performance by lowering exercising HR. Further studies are needed to determine the influence and practical significance of HRW on varying exercise intensities as well as optimal dosing protocols and the effects of chronic use.

Evaluating The Effects of Two-Minutes Active Recovery On A “Booster” VO2max Test Using Ultramarathon Runners

Maximal oxygen consumption (VO2max) tests typically end at the point of volitional exhaustion. However, prior research with averagely fit females and males as well as highly fit female collegiate athletes suggest that concluding a maximal treadmill test with 2min active recovery and allowing subjects to exercise a second time (ie. a booster test) at the workload eliciting the initial volitional exhaustion results in significantly greater VO2max values (1.4% and 4.2% mean increase, respectively). The potential effects of this testing sequence (ie. 2min active recovery) on VO2max treadmill graded exercise tests (GXT) has not been evaluated utilizing ultramarathon runners, yet accurate assessment of these unique athletes’ VO2max is crucial for training program design, implementation, and evaluation of training adaptations. PURPOSE: To examine changes in VO2max values, in fit ultramarathon runners, following 2min of active recovery at the conclusion of a treadmill GXT to volitional exhaustion. METHODS: Twenty-nine (19 males and 10 females) ultramarathon runners completed a max treadmill GXT by reaching volitional exhaustion (MX1). Following 2min active recovery (at 0% grade & 2.5 mph) after reaching MX1, subjects had an immediate return to the ending MX1 speed and grade and exercised (ie. a booster test) to volitional exhaustion a second time (MX2). MX1 and MX2 values were compared using a Paired-Samples t-Test with significant differences occurring at p < 0.05. RESULTS: MX1 (53.9 + 6.0 ml/kg/min) was significantly different (p = 0.03) than MX2 (52.7 + 7.0 ml/kg/min). The mean change from MX1 to MX2 was -2.2%, yet 37.9% of the subjects benefited (+2.9% mean increase) from the booster test with individual increases of +0.2% up to +8.0%. CONCLUSION: Mean results suggest that 2min active recovery may not allow significantly greater VO2max values to be achieved by fit ultramarathon runners during a max treadmill GXT, yet 37.9% of the subjects increased their VO2max during the “booster VO2max test” treadmill protocol. Future research may examine if fitness level, training experience, age, ultramarathon distance specialty, or other variables might affect this exercise testing protocol.

Association Between Anthropometric Characteristics And Aerobic Capacity In Firefighters

Firefighting is a physically demanding profession with high requirements for aerobic capacity (VO2max). However, this population has a high rate of obesity, consistent with the general population. Previous research in general populations has identified a relationship between VO2max and anthropometrics, specifically the impact of body weight and lean body mass. Moreover, research suggests an association between increased percent body fat (%BF) and decreased aerobic and strength measures in similar tactical populations such as military. However, this relationship has not been thoroughly examined in firefighters. PURPOSE: To determine the association between anthropometric characteristics and VO2max of firefighters. METHODS: Eighteen healthy firefighters (Age= 39.9 ± 11.0 years; Body Mass Index (BMI)= 28.0 ± 3.4kg/ m2; %BF= 27.1 ± 8.7%; Waist to Hip Ratio (WHR)= 0.88 ± 0.04; VO2max= 41.2 ± 7.5ml/kg/min) completed measurements of anthropometry (height, weight, bioelectrical impedance analysis, waist and hip circumferences) and a treadmill graded exercise test (GXT) to determineVO2max utilizing open circuit spirometry. Normality was assessed, and Pearson correlation and Spearman coefficients were used when appropriate to determine the associations between VO2max and anthropometric characteristics (BMI, %BF, WHR). RESULTS: Data revealed a significant moderate correlation (r= -0.636; p= 0.005) between %BF and VO2max, indicating that higher levels of body composition are related to lower VO2max. No relationship was found between BMI and VO2max (r= 0.05; p= 0.845), and the association between WHR and VO2max approached significance (r=-0.462; p=0.053). CONCLUSION: Results of the current investigation suggest %BF may be associated with maximal aerobic capacity. Additionally, data revealed no significant relationship between BMI and VO2max, suggesting that total body weight may not have a significant impact on aerobic capacity. Future research should continue to investigate the effects that maintaining an ideal body composition have on work performance and injury risk, including the negative effects of obesity on thermoregulation in job specific tasks for firefighters.

Hemodynamic and Metabolic Responses to Self-Paced and Ramp Graded Exercise Protocols

PURPOSE: Compare metabolic and hemodynamic responses between self-paced (SP) and ramp (RAMP) graded exercise testing (GXT) protocols. Given that SP is controlled for time while RAMP is not, similarities in physiological responses between protocols may support SP as a viable testing option from a time-management standpoint. METHODS: Sixteen recreationally trained men (23.7±3.0 yrs) completed two separate treadmill GXT protocols. SP consisted of five 2-min stages (10 min total) of increasing speed clamped by the Borg RPE6-20 scale. RAMP increased speed by 0.16 km/hr every 15 s until volitional exhaustion. All testing was performed at 3% incline. Oxygen consumption (VO ) was measured via indirect calorimetry; hemodynamic function was measured via thoracic impedance, and blood lactate (BLa-) was measured via portable lactate analyzer. Differences between SP and RAMP protocols were analyzed as group means by using paired samples t-tests (R Core Team (2017)). RESULTS: Maximal values for SP and RAMP were similar (p > 0.05) for VO (47.1±3.4 vs. 47.4±3.4 mL•kg-1•min-1), heart rate (198±5 vs. 200±6 beats•min-1), ventilation (158.8±20.7 vs. 159.3±19.0 L•min-1), cardiac output (26.9±5.5 vs. 27.9±4.2 L•min-1), stroke volume (145.9±29.2 vs. 149.8±25.3 mL•beat-1), arteriovenous oxygen difference (18.5±3.1 vs. 19.7±3.1 mL•dL-1), and peak BLa- (11.7±2.3 vs. 11.5±2.4 mM•L-1), respectively. CONCLUSIONS: SP elicits similar maximal metabolic and hemodynamic responses in comparison to RAMP for our sample. These results support SP as a feasible GXT protocol. Electing to utilize SP may benefit clinicians and researchers from a time-management perspective.