Maximal Treadmill Test Research Articles

Test-retest reliability of exercise blood pressure and the workload-indexed systolic blood pressure slope in healthy males and females.

The reliability of blood pressure (BP) measured during submaximal and maximal exercise, and confounding effects of biological sex, remain to be fully established but have implications for using exercise BP as a cardiovascular risk factor. We hypothesize that exercise BP test-retest reliability will not differ between sexes but will be higher during submaximal compared to maximal exercise. Eighty-four participants (22±5 years; 36 females) completed two maximal treadmill tests (modified Bruce protocol) separated by ≥2 days. Exercise BP was measured every 90-seconds using automated auscultation (Tango M2 monitor). Breath-by-breath oxygen uptake was analyzed. Test-retest reliability was assessed using two-way, mixed effects, consistency, single-rater intraclass correlation coefficient (ICC) analysis on the total group and separated by sex at submaximal and maximal exercise. Systolic BP during submaximal (ICC=0.65 [0.49-0.76], p<0.01) and maximal (ICC=0.66 [0.52-0.77], p<0.01) exercise both displayed substantial reliability between visits. In contrast, the SBP/MET slope showed poor submaximal (ICC=0.12 [-0.09-0.33], p=0.13) but substantial maximal (ICC=0.63 [0.48-0.75], p<0.01) exercise reliability. Females showed substantial reliability in submaximal systolic BP (ICC=0.73 [0.53-0.85], p<0.01), and peak systolic BP (ICC=0.74 [0.54-0.87], p<0.01) and SBP/MET slope (ICC=0.78 [0.60-0.88], p<0.01); the submaximal SBP/MET slope had fair reliability (ICC=0.28 [-0.06-0.56], p=0.05). Males showed moderate reliability in submaximal systolic BP (ICC=0.53 [0.26-0.72], p<0.01), and peak systolic BP (ICC=0.41 [0.15-0.62], p<0.01) and SBP/MET slope (ICC=0.48 [0.22-0.67], p<0.01); the submaximal SBP/MET slope had poor reliability (ICC=0.06 [-0.18-0.31], p=0.32). Systolic BP showed similar reliability during submaximal and maximal exercise, with females demonstrating higher reliability in exercise systolic BP compared to males.

Differences in Workloads of Maximal Tasks in Active-Duty Firefighters.

The purpose of this study was to compare the workload of a maximal treadmill test (TREAD) and a fire suppression task (BURN) in firefighters and to examine their relationships to fitness as measured by body mass index (BMI), percent body fat (BF%), and peak aerobic capacity (VO2PEAK). The amount of time spent in the heart rate (HR) intensity ranges of 50-59% HRMAX (ZONE1), 60-69% HRMAX (ZONE2), 70-79% HRMAX (ZONE3), 80-89% HRMAX (ZONE4), and ≥90% HRMAX (ZONE5) quantified the workload as the Edward's Training Impulse for TREAD (ETRIMPTREAD) and BURN (ETRIMPBURN). The ETRIMPTREAD was significantly less than ETRIMPBURN. For TREAD, ZONE5 > ZONE2 and ZONE3. For BURN, ZONE4 > ZONE1, ZONE2, and ZONE5 > ZONE1, ZONE2, and ZONE3. A lower BF% and greater VO2PEAK were related to a greater ETRIMPTREAD and unrelated to ETRIMPBURN. For BURN only, a lower BF% and greater VO2PEAK were related to less time in ZONE5. BMI was unrelated to all workload measures. Laboratory-based maximal exercise testing does not adequately reflect the workload of simulated fire suppression and therefore may not be indicative of firefighter readiness to meet job demands. Less-fit firefighters rely on higher cardiovascular intensities to complete the same workload, and practitioners should consider this when selecting strategies to reduce job-associated cardiovascular risk.

Physiological Responses in Trail Runners during a Maximal Test with Different Weighted-Vest Loads.

During some trail running races, athletes have to carry hydration support, food, and technical and safety equipment, which generates an additional load that must be mobilized during the race. The aim of the present study was to determine the physiological responses to overload running and the effect they may have on metabolic zones. Seventeen well-trained male trail runners (n = 17) completed three maximal treadmill tests with weighted vests at 0%, 5%, and 10% of their body mass (L0, L5, and L10). Their gas exchange was monitored to assess their ventilatory thresholds 1 (VT1) and 2 (VT2), maximal fat oxidation zone (FatMax), and peak oxygen consumption (VO2peak). Their heart rate (HR), power, and velocity (V) were tracked to compare their behavior. One-way ANOVA showed significant differences in the V (p < 0.001; ηp2 = 0.4620) as a limitation for reaching the peak velocity (Vpeak), with a significant decrease in the Vpeak with the L10 compared to the L0 (p = 0.002) and L5 (p = 0.004). In addition, one-way ANOVA showed significant differences in the peak absolute power (p < 0.001; ηp2 = 0.468) among the groups, detecting higher power production between the L10 and L0 (p < 0.001) and between the L10 and L5 (p = 0.015). Loads higher than L5 could generated important physiological and mechanical modifications, while a load of L5 managed to maintain the working conditions without overloading. These insights shed light on nuanced strategies for optimizing performance and endurance, offering valuable considerations for athletes seeking to enhance their training regimens during overload conditions.

Reassembling the Field-based Applicability of the Lactate Threshold for Old Age.

This study aimed to investigate the applicability of the Lactate Threshold (LT) to predict maximal oxygen uptake (˙VO2max) and demarcate the boundary between the moderate- to heavy-intensity domain (HRm-h) in old age in comparison to the most utilized methods. A cross-sectional validation study was conducted. Participants aged 61 to 77 performed a familiarization procedure, an incremental maximal exercise treadmill test (CPX) for ˙VO2max determination, the Six-minute Walk Test (6MWT), and a discontinuous incremental field test for LT determination. Lower (P<0.01) internal effort was required for LT testing (76±8%HRmax) compared to 6MWT (92±9%HRmax). The application of the 6MWT reference equations overestimated ˙VO2max by 10-23%. LTs better estimated the ˙VO2max (r ≈0.90, SEE: ≈3.0] compared to the 6MWT (r=0.68, SEE=5.5). HRm-h determined by the CPX differed (20%; P=0.001) from that obtained by LT. HRm-h stratification indicated participants fall into the very light to the vigorous intensity domains. LT testing is more submaximal than the 6MWT, and is a valuable tool to estimate the ˙VO2max in older male adults. Implementation of LT testing in physical activity programs might help improving the quality of aerobic exercise training in older men.

Analysis of Kinematic Variables According to Menstrual Cycle Phase and Running Intensity: Implications for Training Female Athletes

Depending on the phase of the menstrual cycle, different values of running kinematic variables can be obtained. The aim of this study is to analyze whether there are changes in the kinematic variables in running throughout the menstrual cycle and to relate them to running performance and injury prevention. Eight regular female runners and triathletes performed a maximal treadmill test, as well as a submaximal test (6′ stages at 50%, 60% and 80% of maximal aerobic speed) in each of the phases of the menstrual cycle: menstruation phase (day 2.4 ± 0.7), follicular phase (day 10.4 ± 2.2) and luteal phase (day 21.8 ± 2.1). Running dynamics were measured using RunScribe. For parametric data, a general linear model of repeated measures was applied, with two intrasubject independent variables, menstrual cycle phases (with three levels: Menstruation, Follicular, and Luteal) and running intensity (with four levels relative to the maximum speed reached in the test: 100%, 80%, 60%, and 50%). For variables with non-normal distributions, Friedman tests were performed with Wilcoxon post-tests adjusted for significance according to Bonferroni. The maximum stance velocity from foot strike to the point of maximum pronation (°/s) was higher in the menstruation phase than in the follicular and luteal phases (p = 0.008), the step rate (s/min) was higher in the follicular phase than in the menstruation and luteal phases (p = 0.049), the vertical velocity (m/s) was lower in the follicular phase than in the menstruation (p = 0.004) and luteal phases (p = 0.003), and the contact time (ms) was lower in the luteal phase than in the menstruation and follicular phases. These results suggest that training at high intensities could be a factor in greater risk of injury in female athletes, especially in the menstruation phase, finding in the luteal phase and at an intensity of 80% a greater efficiency in the running.

Heart Rate, Oxygen Uptake and Anaerobic Thresholds During a Maximal Treadmill Test with World Class Mixed Martial Arts Fighters

Measuring heart rate responses during a competitive mixed martial arts (MMA) fight is not feasible; therefore, a method is needed to assess physiological responses in MMA fighters outside of competition. Quantifying and evaluating heart rate, oxygen uptake, and anaerobic threshold during a maximal treadmill test can provide interpretation for in-competition physiological responses of MMA fighters The retrospective analysis was conducted on 20 world-class MMA fighters predating the beginning of their fight camps (ages 29.0 ± 4.8 years old). A maximal treadmill test utilizing a ramp protocol was conducted eight weeks prior to a professional competition. Fighters’ data were divided in two groups based on weight status: lighter, &lt; 185 pounds (n = 12) and heavier, ≥ 185 pounds (n = 8) weight groups. Heart rate (HR), anaerobic thresholds from respiratory exchange rate (RER-AT), and oxygen uptake (VO2max) were recorded and compared between weight groups. VO2max was the only physiological variable measured that differed between lighter (53.4 ± 4.5 ml . kg−1 . min−1) and heavier (48.1 ± 5.7 ml . kg−1 . min−1) fighters (p = 0.033). Previous literature has commonly used 1.0 RER to determine the breaking point in anaerobic thresholds. All other variables were not different (p ≥ 0.204) between groups. Differences in VO2max between lighter and heavier fighters is likely due to differences in body mass. While there were no differences in heart rates at RER-AT or time to exhaustion between weight status groups, using RER-AT at 0.95 or 1.0 RER may be a valuable way to ensure an MMA athlete achieve anaerobic training in fight preparation. Performance coaches may utilize physiological variables such as RER-AT acquired from maximal treadmill testing to guide the training demands of MMA competition.

CHRONIC KIDNEY DISEASE INCIDENCE AND CARDIORESPIRATORY FITNESS ASSOCIATION IN HYPERTENSIVE PATIENTS

Objective: Chronic hypertension (HTN) is considered a strong risk factor for developing chronic kidney disease (CKD). Increased cardiorespiratory fitness (CRF) is associated with lower CKD risk. However, the CRF-CKD association in patients with HTN has not been assessed. Thus, we examined the the association between CRF and the risk of developing CKD in hypertensive patients. Design and method: Hypertensive individuals (n=471,579; age 63.0+8.8 years) with normal kidney function prior to HTN and no evidence of ischemia indicated by a maximal standardized exercise treadmill test (ETT). The cohort was part of the ETHOS study (n=750,302). We established five CRF categories based on age-and-gender-adjusted peak metabolic equivalents (METs) achieved: Least-Fit (4.5±1.2 METs; n=106,955); Low-Fit Fit (6.9±1.1 METs; n=122,612); Moderate-Fit (8.3±1.2 METs; n=91,995); Fit (10.3±1.2 METs; n=111,472); and High-Fit (13.2±1.6 METs; n=38,545). CKD risk across CRF categories was assessed by multivariable Cox Regression analysis, adjusted for age, blood pressure, body mass index (BMI), alcohol abuse, traditional risk factors, and medications. Results: During 6,146,773.0 person-years of follow-up (median 12.9 years), 58,701 individuals developed CKD (9.6 events/1,000 person-years of observation). The CRF-CKD association was inverse, independent of comorbidities and graded. The risk of developing CKD was 9% lower for each 1-MET increase (Hazard Ratio [HR] 0.91; 95% confidence interval [CI] 0.90-0.93). When CKD risk was assessed across CRF categories using the Least-fit category as the referent, the risk was 20% lower (HR 0.80; CI 0.78-0.81, p&lt;0.001) for those in the Low-fit category (6.9±1.1 METs). The risk declined progressively with increased CRF and was 49% lower for those in the highest CRF category (HR 0.49; CI 0.47-0.51, p&lt;0.001). Similar findings were observed in the subgroup of hypertensive patients with diabetes mellitus (n=192,966). Conclusions: We noted an inverse and dose-response association between CRF and CKD incidence. The risk was attenuated significantly beyond a MET level of 6.9±1.1 METs, suggesting that moderate increases in exercise capacity lowers the risk of developing CKD in hypertensive patients.

The Impact of Cardiorespiratory and Metabolic Parameters on Match Running Performance (MRP) in National-Level Football Players: A Multiple Regression Analysis

The aim of the study was to examine the association between cardiorespiratory and metabolic parameters and match running performance (MRP) in highly trained football players. The sample of participants consisted of 41 national-level football players (aged 23.20 ± 3.40 years, body height 182.00 ± 5.15 cm, and body mass 76.86 ± 6.06 kg) from the Serbian Super league. For the purposes of this research, the following measurements were applied. A maximal multistage progressive treadmill test, with a direct measurement of maximal oxygen consumption (VO2max) (using Fitmate MED, Cosmed, Rome, Italy) was conducted, alongside continuous heart rate monitoring. Capillary blood samples were taken from the hyperemic area using specific test strips, and, after sample collection, lactate concentration was immediately determined using a lactate analyzer. MRP variables were analyzed according to the BioIRC model of motion structure analysis, based on existing standards for profiling movement intensity. The results of multiple regression analysis indicated an association between cardiac parameters and total distance (R2 = 54.3%, p = 0.000), high-speed running (R2 = 46.4%, p = 0.000), and jogging (R2 = 33.6%, p = 0.004). Regression analysis revealed an association between cardiorespiratory parameters and total distance (R2 = 24.8%, p = 0.014), and high-speed running (R2 = 20%, p = 0.039). Meanwhile, no association was found between lactate concentration and running performance. The explanation for these regression analysis results is based on the observation that functional abilities represent significant potential for expressing movement performance, a crucial condition for success in football.

The Relationship between Aerobic Capacity, Anthropometric Characteristics, and Performance in the Yo-Yo Intermittent Recovery Test among Elite Young Football Players: Differences between Playing Positions

The objectives of this study were to investigate (a) the relationship between the Yo-Yo intermittent recovery test level 1 (YYIR1) and a laboratory test for measuring maximal oxygen uptake (VO2max), (b) the relationships between anthropometric characteristics and variables of the two aerobic tests (field and laboratory), and (c) differences in performance and anthropometric characteristics among five different playing positions. The study involved 27 U17 young soccer players (16.0 ± 0.6 years). They randomly underwent a maximal laboratory treadmill test to measure VO2max and the YYIR1 test. Pearson correlation was used to find potential correlations, and a one-way ANOVA was used to find differences between playing positions. Statistical significance was set at p &lt; 0.05. The results showed that height was moderately negatively correlated (r = −0.455, p = 0.017) as well as body mass (r = −0.395, p = 0.042). Significant positive correlation was observed between vVO2max and the distance covered in YYIR1 (r = 0.393, p = 0.042). Finally, no differences were observed between playing positions in any anthropometric characteristic or in any variable of the two aerobic tests (laboratory or field) (p &gt; 0.05). In conclusion, the YYIR1 test is not suitable for estimating VO2max. Additionally, the lack of differences between playing positions may be due to the limited specialization of the training load received by the players until this age.

Acetaminophen influences musculoskeletal signaling but not adaptations to endurance exercise training.

Acetaminophen (ACE) is a widely used analgesic and antipyretic drug with various applications, from pain relief to fever reduction. Recent studies have reported equivocal effects of habitual ACE intake on exercise performance, muscle growth, and risks to bone health. Thus, this study aimed to assess the impact of a 6-week, low-dose ACE regimen on muscle and bone adaptations in exercising and non-exercising rats. Nine-week-old Wistar rats (n = 40) were randomized to an exercise or control (no exercise) condition with ACE or without (placebo). For the exercise condition, rats ran 5 days per week for 6 weeks at a 5% incline for 2 min at 15 cm/s, 2 min at 20 cm/s, and 26 min at 25 cm/s. A human equivalent dose of ACE was administered (379 mg/kg body weight) in drinking water and adjusted each week based on body weight. Food, water intake, and body weight were measured daily. At the beginning of week 6, animals in the exercise group completed a maximal treadmill test. At the end of week 6, rats were euthanized, and muscle cross-sectional area (CSA), fiber type, and signaling pathways were measured. Additionally, three-point bending and microcomputer tomography were measured in the femur. Follow-up experiments in human primary muscle cells were used to explore supra-physiological effects of ACE. Data were analyzed using a two-way ANOVA for treatment (ACE or placebo) and condition (exercise or non-exercise) for all animal outcomes. Data for cell culture experiments were analyzed via ANOVA. If omnibus significance was found in either ANOVA, a post hoc analysis was completed, and a Tukey's adjustment was used. ACE did not alter body weight, water intake, food intake, or treadmill performance (p > .05). There was a treatment-by-condition effect for Young's Modulus where placebo exercise was significantly lower than placebo control (p < .05). There was no treatment by condition effects for microCT measures, muscle CSA, fiber type, or mRNA expression. Phosphorylated-AMPK was significantly increased with exercise (p < .05) and this was attenuated with ACE treatment. Furthermore, phospho-4EBP1 was depressed in the exercise group compared to the control (p < .05) and increased in the ACE control and ACE exercise group compared to placebo exercise (p < .05). A low dose of ACE did not influence chronic musculoskeletal adaptations in exercising rodents but acutely attenuated AMPK phosphorylation and 4EBP1 dephosphorylation post-exercise.

Effect of Short Bouts of Vigorous Stair Climbing on Cardiorespiratory Fitness in Women with Overweight and Obesity: A Pilot Feasibility Study.

We examined the effect of 4 weeks of a brief vigorous stair climbing exercise on cardiorespiratory fitness (CRF) and body composition in women with overweight or obesity. Twenty-six participants (age, 25.4±4.9 years; body mass index [BMI], 25.3±1.8 kg/m2) were randomly assigned to either a stair climbing exercise group (n=13) or a non-exercising control group (n=13). The stair climbing exercise group performed 20 sessions (supervised, five sessions/week over 4 weeks) of brief intermittent stair climbing exercise consisting of a 3-minute warm-up followed by three bouts of 20 seconds of stair climbing (≥80% of age-predicted maximum heart rate) interspersed with 2-minute recovery periods (total exercise duration=10 minutes/session). Peak oxygen uptake (VO2peak) was measured using a graded maximal treadmill test with the use of a standard open-circuit spirometry technique. Body composition was assessed with bioelectrical impedance analysis. All participants, except one who dropped out due to coronavirus disease 2019 (COVID-19) infection, completed the study with 100% attendance rates. There were significant interaction effects (group×time) on body weight, BMI, waist circumference, and CRF such that the stair climbing exercise group had significant (P≤0.01) reductions in body weight (66.5±4.6 to 65.2±4.6 kg), BMI (24.8±1.2 to 24.4±1.1 kg/m2), and waist circumference (78.0±3.7 to 76.5±4.1 cm) and improvements in VO2peak (31.6±2.5 to 34.9±2.6 mL/kg/min) compared with controls. Short bouts of vigorous stair climbing is a feasible and time-efficient exercise strategy for improving CRF in previously sedentary, young women with overweight and obesity.

Kinetic, Physiological and Fatigue Level Differences Depending on the Menstrual Cycle Phase and Running Intensity

Background: Depending on the phase of the menstrual cycle an athlete is in, some kinetic, physiological, and fatigue variables will show differences. The aim of this study is to analyze whether there are changes in these variables over the course of the menstrual cycle. Methods: Eight regularly practicing women runners and triathletes performed a maximal treadmill test and a submaximal test (6′ stages at 50%, 60%, and 80% of maximal aerobic speed) in each of the phases of the menstrual cycle: bleeding phase (day 2.4 ± 0.7), follicular phase (day 10.4 ± 2.2), and luteal phase (day 21.8 ± 2.1). Running dynamics were measured (using RunScribe) at the end of each test, as were lactate concentration, heart rate, and fatigue (evaluated on a scale of 0–5). Results: Higher shock (G) values were recorded in the bleeding phase (η2 = 0.27) and higher vertical spring stiffness (kN/m) was recorded in the follicular phase (η2 = 0.25). The phase of the menstrual cycle had a significant effect on average and peak heart rate, which was significantly higher in the follicular phase (η2 = 0.45 and η2 = 0.48, respectively). Conclusions: Higher vertical spring stiffness was observed in the follicular phase, in addition to higher peak and average heart rate.

Change in Peak Oxygen Uptake Predicted by the Moderate 1-km Treadmill Walking Test After Walking Training in Outpatients With Cardiovascular Disease.

The purpose of this study was to determine the ability of the moderate 1-km treadmill walking test (1km-TWT) to predict changes in peak oxygen uptake (V˙O 2peak ) in patients with stable cardiovascular disease (CVD) during an exercise-based secondary prevention program. Sixty-four male outpatients with stable CVD (age 64 [41-85] yr) performed the 1km-TWT before and after an 8-wk walking training program. Patient V˙O 2peak was estimated using a sex-specific equation including age, body mass index, 1km-TWT performance time, and heart rate (V˙O 2peakEST ). Forty-one patients completed a maximal cardiopulmonary treadmill test (CPX) for direct V˙O 2peak determination (V˙O 2peakMEAS ). The training prescription consisted of moderate-to-high intensity supervised walking for 30-40 min/session, and an additional 2-4 times/wk of unsupervised home moderate walking sessions between 20-60 min at the end of the program. The walking intensity was based on the results of the 1km-TWT. Patients participated in an average of 14 of the 16 supervised sessions. An overall significant improvement in V˙O 2peakMEAS and weekly recreational physical activity levels were observed. No differences were observed between V˙O 2peakMEAS and V˙O 2peakEST . Compared with CPX results, the 1km-TWT underestimated the V˙O 2peak increase after the exercise intervention (mean difference -0.3 mL/kg/min, P > .05). The 1km-TWT provides a reasonably accurate and simple tool to predict changes in V˙O 2peak due to moderate walking training in male outpatients with CVD. These findings contribute to the growing body of evidence supporting the use of the 1km-TWT for exercise testing and training purposes in the context of cardiac rehabilitation/secondary prevention programs.

Higher exercise capacity, but not omega-3 fatty acid consumption, predicts lower coronary artery calcium scores in women and men with coronary artery disease

Background and aimsHigher coronary artery calcium (CAC) scores are associated with increased cardiovascular (CVD) events and mortality. Exercise capacity is predictive of CVD events. Our aim was to examine the relationship between exercise capacity and CAC in women and men. MethodsCAC was measured in 203 men and 38 women with clinical coronary artery disease using multidetector coronary tomography. They were randomized to 3.36 g eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) daily or none for 30 months. Maximal exercise treadmill testing was performed at baseline with calculation of metabolic equivalents of task (METs) achieved as a measure of exercise capacity. ResultsDespite similar ages at baseline (64.0 ± 6.7 vs 62.7 ± 7.8 years, respectively, p = 0.225), women had lower CAC scores compared to men: 106.7 Agatston units [AU] vs 535.3, respectively, p < 0.001, and at every age (p < 0.001). Female CAC scores did not equal those of men until women were 20 years older. Higher levels of METs were associated with lower CAC scores in both women and men. After multivariate adjustment, METs was the most important predictor of CAC score in women at baseline and 30 months (p = 0.001 and 0.029, respectively) whereas only age predicted in men (p = 0.019 and 0.004, respectively). Annual CAC progression was significantly greater in men compared to women (94.8 AU/year vs 38.0, respectively, p = 0.014). No difference was observed in CAC progression in the EPA + DHA group compared to control in either men or women. ConclusionsThe association of higher METs with lower CAC scores in both women and men supports recommending exercise to maximize cardiorespiratory fitness as this may minimize CAC scores and thus, potentially decrease risk for CVD events. This may be especially important for women since METs independently predicted baseline and 30 month CAC in women.

Body Composition Is Related to Maximal Effort Treadmill Test Time in Firefighters.

Firefighting tasks may require near maximal levels of cardiorespiratory fitness. Previous research has indicated that body fat percentage (BF%) and aerobic capacity (VO2peak) are related to the performance of firefighting tasks. Since a standard submaximal treadmill test for firefighters is terminated at 85% of maximal heart rate (MHR), key performance information relating to maximal cardiorespiratory effort may not be measured in a submaximal test. The purpose of this study was to examine the relationships between body composition and time spent running at intensities greater that 85% MHR. Height, weight, body mass index (BMI; kg/m2), BF%, MHR (bpm), VO2peak (mL/kg/min), predicted VO2peak (P-VO2peak; mL/kg/min), submaximal treadmill test time (WFIsub Test Time; min), and maximal treadmill test time (WFImax Test Time; min) were collected in fifteen active-duty firefighters. The results indicated that significant relationships (p < 0.05) existed between BF% and VO2peak, BF% and WFImax Test Time, BF% and Tdiff, and VO2peak and WFImax Test Time. P-VO2peak was not significantly different than VO2peak, and the WFImax Test Time was significantly longer than the WFIsub Test Time. These results indicate that a submaximal treadmill test may reasonably predict VO2peak, but key information about physiological work at intensities greater than 85% MHR may be missed when using submaximal effort tests.

Association between cardiorespiratory fitness and low back pain is anxiety-dependent: A prospective cohort study among adults and older adults

ABSTRACT To investigate the relationship between low back pain and cardiorespiratory fitness (CRF) among participants with and without self-report anxiety. Participants were 13,080 individuals (86.6% men; 44.7 ± 9.3 years). CRF was quantified as maximal treadmill test duration and was grouped for analysis as low (lowest 20% of treadmill test duration), moderate (middle 40%), and high (upper 40%). Cox regression analysis was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) between low back pain and CRF according to the presence/absence of self-report anxiety. During an average of 5.7 ± 5.1 years of follow-up, 2,965 cases of low back pain were identified. Participants with self-report anxiety and low CRF had 3.7 times (HR: 3.7; 95%CI: 1.7–8.2) more risk for having low back pain when compared with participants with self-report anxiety and high CRF. Additionally, among participants with self-reported anxiety, moderate CRF was associated with an 70% greater risk of having low back pain than those with high CRF (HR: 1.7; 95%CI: 1.1–3.2). For participants without self-reported anxiety, no association was found between the risk of having low back pain and CRF. According to the results identified in the present study, participants with self-reported anxiety who had low and moderate CRF had higher risks of low back pain than those with high CRF.

The relationship of muscle oxygen saturation analyzer with other monitoring and quantification tools in a maximal incremental treadmill test.

Introduction: The study aims to explore whether NIRS derived data can be used to identify the second ventilatory threshold (VT2) during a maximal incremental treadmill test in non-professional runners and to determine if there is a correlation between SmO2 and other valid and reliable exercise performance assessment measures or parameters for maximal incremental test, such as lactate concentration (LT), RPE, HR, and running power (W). Methods: 24 participants were recruited for the study (5 women and 19 men). The devices used consisted of the following: i) a muscle oxygen saturation analyzer placed on the vastus lateralis of the right leg, ii) the Stryd power meter for running, iii) the Polar H7 heart rate band; and iv) the lactate analyzer. In addition, a subjective perceived exertion scale (RPE 1-10) was used. All of the previously mentioned devices were used in a maximal incremental treadmill test, which began at a speed of 8km/h with a 1% slope and a speed increase of 1.2km/h every 3min. This was followed by a 30-s break to collect the lactate data between each 3-min stage. Spearman correlation was carried out and the level of significance was set at p < 0.05. Results: The VT2 was observed at 87,41 ± 6,47% of the maximal aerobic speed (MAS) of each participant. No relationship between lactate data and SmO2 values (p = 0.076; r = -0.156) at the VT2 were found. No significant correlations were found between the SmO2 variables and the other variables (p > 0.05), but a high level of significance and strong correlations were found between all the following variables: power data (W), heart rate (HR), lactate concentration (LT) and RPE (p < 0.05; r > 0.5). Discussion: SmO2 data alone were not enough to determine the VT2, and there were no significant correlations between SmO2 and the other studied variables during the maximal incremental treadmill test. Only 8 subjects had a breakpoint at the VT2 determined by lactate data. Conclusion: The NIRS tool, Humon Hex, does not seem to be useful in determining VT2 and it does not correlate with the other variables in a maximal incremental treadmill test.

Association between Estimated Cardiorespiratory Fitness and Abnormal Glucose Risk: A Cohort Study.

Cardiorespiratory fitness (CRF) is a predictor of chronic disease that is impractical to routinely measure in primary care settings. We used a new estimated cardiorespiratory fitness (eCRF) algorithm that uses information routinely documented in electronic health care records to predict abnormal blood glucose incidence. Participants were adults (17.8% female) 20-81 years old at baseline from the Aerobics Center Longitudinal Study between 1979 and 2006. eCRF was based on sex, age, body mass index, resting heart rate, resting blood pressure, and smoking status. CRF was measured by maximal treadmill testing. Cox proportional hazards regression models were established using eCRF and CRF as independent variables predicting the abnormal blood glucose incidence while adjusting for covariates (age, sex, exam year, waist girth, heavy drinking, smoking, and family history of diabetes mellitus and lipids). Of 8602 participants at risk at baseline, 3580 (41.6%) developed abnormal blood glucose during an average of 4.9 years follow-up. The average eCRF of 12.03 ± 1.75 METs was equivalent to the CRF of 12.15 ± 2.40 METs within the 10% equivalence limit. In fully adjusted models, the estimated risks were the same (HRs = 0.96), eCRF (95% CIs = 0.93-0.99), and CRF (95% CI of 0.94-0.98). Each 1-MET increase was associated with a 4% reduced risk. Higher eCRF is associated with a lower risk of abnormal glucose. eCRF can be a vital sign used for research and prevention.

Hip Hop Party Dance: Cardiorespiratory Profile and Responses to a Predefined Sequence.

Hip hop is a popular dance genre practiced worldwide that has gained popularity since the 1970s. Despite this, studies related to the area and its physiological demands are still scarce. The purpose of this study was to report the cardiorespiratory profile of a group of male and female hip hop dancers to determine the zones of intensity of a predefined hip hop party dance sequence. Eight Brazilian professional hip hop dancers, four women and four men, mean age 22 ± 2.3 years, participated in the study. Using a portable gas analyser (Cosmed K5) their cardiorespiratory variables were measured at two different times: first, during a maximal treadmill test and later during a predefined hip hop party dance sequence. Descriptive statistics (mean and standard deviation) were used for calculating the dependent variables: oxygen consumption (VO2), heart rate (HR), and the intensity zones for the predefined hip hop sequence. Data normality was verified using the Shapiro-Wilk test. The Mann-Whitney U-test was performed to check any sex-related difference (p < 0.01). No statistical difference between male and female dancers was found in the cardiorespiratory profile and responses to the predefined hip hop party dance sequence. On the treadmill, the participants' VO2peak was 57.3 ± 12.7 ml·kg-1·min-1, and HRmax was 190.0 ± 9.1 b·min-1. The predefined hip hop party dance sequence was mainly (61%) performed in the moderate aerobic zone. However, when the dancers jumped, the intensity of the sequence increased. This information could be used to develop a specific supplementary training protocols for hip hop dancers to improve their physiological fitness parameters and reduce the incidence of injury.

Validity and sensitivity of field tests' heart-rate recovery assessment in recreational football players.

We aimed at examining the criterion validity and sensitivity of heart-rate recovery (HRRec) in profiling cardiorespiratory fitness in male recreational football players in the untrained and trained status, using endurance field-tests. Thirty-two male untrained subjects (age 40 ± 6 years, VO2max 41.7 ± 5.7 ml·kg-1·min-1, body mass 82.7 ± 9.8 kg, stature 173.3 ± 7.4 cm) participated in a 12-week (2‒3 sessions per week) recreational football intervention and were tested pre- and post-intervention (i.e. untrained and trained status). The participants performed three intermittent field tests for aerobic performance assessment, namely Yo-Yo intermittent endurance level 1 (YYIE1) and level 2 (YYIE2) tests, and Yo-Yo intermittent recovery level 1 (YYIR1) test. VO2max was assessed by performing a progressive maximal treadmill test (TT) and maximal HR (HRmax) determined as the maximal value across the testing conditions (i.e., Yo-Yo intermittent tests or TT). HRRec was calculated as the difference between Yo-Yo tests' HRpeak or HRmax and HR at 30 s (HR30), 60 s (HR60) and 120 s (HR120) and considered as beats·min-1 (absolute) and as % of tests' HRpeak or HRmax values. Significant post-intervention improvements (p<0.0001) were shown in VO2max (8.6%) and Yo-Yo tests performance (23-35%). Trivial to small (p>0.05) associations were found between VO2max and HRRec (r = -0.05-0.27, p>0.05) across the Yo-Yo tests, and training status either expressed as percentage of HRpeak or HRmax. The results of this study do not support the use of field-test derived HRRec to track cardiorespiratory fitness and training status in adult male recreational football players.