Search Results (33)

The purpose of this study was to determine the accuracy and inter-device reliability of the OTBeat Burn^TM heart rate monitor during an incremental test to exhaustion on a cycle ergometer. Twenty males (mean ± SD age = 21.1 ± 1.9 years) volunteered to complete a test to exhaustion on a cycle ergometer with OTBeat Burn^TM devices placed on the forearm and upper arm, with a 12-lead electrocardiogram used as the criterion. The heart rate was recorded every 30 s and averaged across each two-minute stage. Accuracy was assessed through calculation of the mean absolute percent error (MAPE), Bland–Altman plot, and Lin’s concordance correlation coefficient (CCC). An intraclass correlation coefficient (ICC) was used to assess the inter-device reliability. Statistical significance was set at α < 0.05. The MAPE (±SD), Bland–Altman regression analyses, and Lin’s CCC values were 0.9 (±0.6)% and 0.8 (±0.5)%, r = 0.107 and 0.303, and r_c = 0.998 and 0.998 for the forearm and the upper arm monitors, respectively. The ICC for inter-device reliability was R = 0.999. Our findings indicated the OTBeat Burn^TM monitors placed on the forearm and upper arm provided highly accurate and reliable values when compared to an electrocardiogram from low to maximal exercise intensities. Full article

Background: Understanding the responses of the cardio and respiratory systems during exercise, as well as their coupling in post-exercise recovery, is important for the prescription of exercise programs in physically recreative subjects. Aim: In this work, we aimed to set up an adjusted experiment to evaluate the relations and changes in parameters obtained from an analysis of cardiac and respiratory signals under three physiological conditions: relaxation, exercise, and post-exercise recovery. Material and Methods: Simultaneously recorded ECG (RR intervals) and respiratory signal during relaxation, bicycle ergometry exercise until submaximal heart rate (HR), and recovery in 10 healthy men were analyzed. The exercise included consecutive phases of 3 min in duration with a constant workload. Parasympathetic cardiac control (RMSSD), heart rate (HR), breathing frequency (BF), and respiratory cycle amplitude (RCA) were calculated. Anthropometric data were also collected. Results: Based on time series analysis, our results show that: (1) during exercise, an increase in HR was related to a reduction in HR variability and RMSSD, while an increase in BF was related to an increase in RCA, and (2) during recovery, HR and RCA significantly decreased, while RMSSD had a biphasic response. The results of multiple linear regressions showed that the averaged HR, RMSSD, and BF during 3 min segments of recovery were determined by several calculated and collected parameters. Conclusions: The parameters from the analysis of respiratory signals and RR interval time series under conditions of relaxation and exercise, along with anthropometric data, contributed to the complexity of the post-exercise recovery of cardiopulmonary parameters after submaximal HR exercise in healthy recreative males. Full article

Recommendations for endurance exercise prescription are often based on percentages of heart rate (HR) or the volume of oxygen consumption ($\dot{\mathrm{V}}$O₂) maximum or reserve that is extrapolated to a power output (P) or velocity. Previous work has demonstrated dissociations of the expected responses to exercise anchored to the critical heart rate (CHR) compared with the P associated with CHR. However, it is unclear if similar dissociations due to reductions in P to maintain the designated intensity would be present during exercise anchored to the $\dot{\mathrm{V}}$O₂ associated with CHR ($\dot{\mathrm{V}}$O₂CHR). The purpose of this study was to examine the patterns in physiological ($\dot{\mathrm{V}}$O₂, HR, P, respiration rate [RR], muscle oxygen saturation [%SmO₂]), neuromuscular (electromyographic and mechanomyographic amplitude [EMG AMP, MMG AMP], mean power frequency [EMG MPF, MMG MPF]), and perceptual (rating of perceived exertion [RPE]) responses during exercise at $\dot{\mathrm{V}}$O₂CHR ($\dot{\mathrm{V}}$O₂-clamp). On separate days, ten participants (age: 25 ± 4 yr) performed a graded exercise test and four constant P trials at 85–100% of peak P (PP) to derive CHR and $\dot{\mathrm{V}}$O₂CHR. Responses were recorded during a trial to exhaustion at $\dot{\mathrm{V}}$O₂CHR (32.86 ± 7.12 mL·kg⁻¹·min⁻¹; T_Lim = 31.31 ± 21.37 min) and normalized in 10% intervals of T_Lim to their respective values at PP. The one-way repeated-measures ANOVA with post hoc, Bonferroni-corrected, pairwise comparisons indicated differences (p < 0.001) from baseline for HR (mean ± SD %change = 8 ± 3%), RR (43 ± 38%), P (−15 ± 5%), EMG MPF (10 ± 8%), and RPE (65 ± 38%), but no differences (p = 0.077–0.955) for %SmO₂ (−17 ± 53%), EMG AMP (−3 ± 16%), MMG AMP (40 ± 61%), and MMG MPF (1 ± 7%). The loss in performance observed during $\dot{\mathrm{V}}$O₂-Clamp exercise may provide a quantification of the inefficiency associated with the $\dot{\mathrm{V}}$O₂ slow component phenomenon. The neuromuscular responses suggested constant muscle excitation despite the reductions in P, but the metabolic and perceptual responses suggested a combination of feedforward and feedback mechanisms regulating T_Lim. Future studies should further examine responses to the $\dot{\mathrm{V}}$O₂-Clamp exercise at a uniform threshold. Full article

Adults who have had an amputation face barriers to having an active lifestyle which attenuates cardiorespiratory fitness. Prior studies in amputees typically involve treadmill walking or arm ergometry, yet physiological responses to bilateral leg cycling are less understood. This study assessed the hemodynamic and metabolic responses to moderate and vigorous cycle ergometry in men who have had a transtibial amputation (TTA). Five men who had had a unilateral TTA (age = 39 ± 15 yr) and six controls (CONs) without an amputation (age = 31 ± 11 yr) performed two 20 min bouts of cycling differing in intensity. Cardiac output (CO), stroke volume (SV), and oxygen consumption (VO₂) were measured during moderate intensity continuous exercise (MICE) and high intensity interval exercise (HIIE) using thoracic impedance and indirect calorimetry. In response to MICE and HIIE, the HR and VO₂ levels were similar (p > 0.05) between groups. Stroke volume and CO were higher (p < 0.05) in the CONs, which was attributed to their higher body mass. In men with TTAs, HIIE elicited a peak HR = 88%HRmax and substantial blood lactate accumulation, representing vigorous exercise intensity. No adverse events were exhibited in the men with TTAs. The men with TTAs show similar responses to MICE and HIIE versus the CONs. Full article

Data on exercise tolerance of children born non-extremely preterm are sparse. We aimed to explore the cardiopulmonary exercise testing (CPET) characteristics in this population. We studied 63 children (age 7–12 years) born at 29^0/7–36^6/7 weeks of gestation (34 were late preterm, 29 were preterm) and 63 age-matched, term-born controls. All performed spirometry and CPET (cycle ergometry). There were no differences in activity levels and spirometric parameters between the group of preterm-born children and controls. A peak oxygen uptake (VO₂peak) of <80% was noted in 25.4% of the term-born and 49.2% of preterm-born children (p = 0.001). Term-born participants presented similar VO₂peak to late-preterm children but higher than those born at <34^0/7 weeks of gestation (p = 0.002). Ventilatory limitation was noted in 4.8% of term and 7.9% of preterm participants, while only one preterm child presented cardiovascular limitation. Children born before 34 weeks of gestation had higher respiratory rates and smaller tidal volumes at maximum exercise, as well as lower oxygen uptake for the level of generated work. We conclude that school-age children born at 29–34 weeks of gestation may present decreased exercise performance attributed to an altered ventilatory response to exercise and impaired O₂ utilization by their skeletal muscles rather than other cardiopulmonary limiting factors. Full article

This study aimed to investigate the test–retest reliability, mean, and individual responses in the measurement of maximal oxygen consumption ($\dot{\mathrm{V}}$O_2max) during a cardiopulmonary exercise test (CPET) and the verification phase during cycle ergometry in women. Nine women (22 ± 2 yrs, 166.0 ± 4.5 cm, 58.6 ± 7.7 kg) completed a CPET, passively rested for 5 min, and then completed a verification phase at 90% of peak power output to determine the highest $\dot{\mathrm{V}}$O₂ from the CPET ($\dot{\mathrm{V}}$O_2CPET) and verification phase ($\dot{\mathrm{V}}$O_{2verification}) on 2 separate days. Analyses included a two-way repeated measures ANOVA, intraclass correlation coefficients (ICC_2,1), standard errors of the measurement (SEM), minimal differences (MD), and coefficients of variation (CoV). There was no test (test 1 versus test 2) × method (CPET vs. verification phase) interaction (p = 0.896) and no main effect for method (p = 0.459). However, test 1 (39.2 mL·kg⁻¹·min⁻¹) was significantly higher than test 2 (38.3 mL·kg⁻¹·min⁻¹) (p = 0.043). The $\dot{\mathrm{V}}$O_2CPET (ICC = 0.984; CoV = 1.98%; SEM = 0.77 mL·kg⁻¹·min⁻¹; MD = 2.14 mL·kg⁻¹·min⁻¹) and $\dot{\mathrm{V}}$O_{2verification} (ICC = 0.964; CoV = 3.30%; SEM = 1.27 mL·kg⁻¹·min⁻¹; MD = 3.52 mL·kg⁻¹·min⁻¹) demonstrated “excellent” reliability. Two subjects demonstrated a test 1 $\dot{\mathrm{V}}$O_2CPET that exceeded the test 2 $\dot{\mathrm{V}}$O_2CPET, and one subject demonstrated a test 1 $\dot{\mathrm{V}}$O_{2verification} that exceeded the test 2 $\dot{\mathrm{V}}$O_{2verification} by more than the respective CPET and verification phase MD. One subject demonstrated a $\dot{\mathrm{V}}$O_2CPET that exceeded the $\dot{\mathrm{V}}$O_{2verification}, and one subject demonstrated a $\dot{\mathrm{V}}$O_{2verification} that exceeded the $\dot{\mathrm{V}}$O_2CPET by more than the MD. These results demonstrate the importance of examining the individual responses in the measurement of the $\dot{\mathrm{V}}$O_2max and suggest that the MD may be a useful threshold to quantify real individual changes in $\dot{\mathrm{V}}$O₂. Full article

Background: Athletes often experience poor sleep quality due to stress, altitude exposure, travel across different time zones, and pre-competition nervousness. Coaches use daytime naps to counteract the negative effects of fragmented nighttime sleep. Napping before competitions has also been used to enhance performance in athletes without sleep problems, with mixed results in previous studies, particularly for endurance performance. Thus, we investigated the effects of napping after partial sleep deprivation (PSD) on endurance performance and wakefulness in athletes. Methods: We recruited 12 healthy and trained participants (seven female and five male) for a randomized crossover study design. The participants underwent two test sessions: a five-hour night of sleep without a nap (noNap) and a five-hour night of sleep with a 30-min nap opportunity (Nap30). Participants recorded their sleep-wake rhythm one week before and during the study using the Consensus Sleep Diary-Core and the Morningness–Eveningness Questionnaire to examine their circadian rhythm type. We quantified PSD and the nap with pupillography (pupil unrest index, PUI), a subjective level of sleepiness questionnaire (Karolinska Sleepiness Scale, KSS), and polysomnography. After each night, participants performed a maximal cycling ergometry test to determine time to exhaustion (TTE) and maximal oxygen uptake (VO _2max). Results: Participants had an average sleep duration of 7.2 ± 0.7 h and were identified as moderately morning types (n = 5), neither type (n = 5), and moderately evening types (n = 2). There was a significant difference in both sleepiness parameters between the two conditions, with the PUI (p = 0.015) and KSS (p ≤ 0.01) significantly decreased at 5 h and nap compared with only 5 h of sleep. The PUI (p ≤ 0.01) and KSS (p ≤ 0.01) decreased significantly from before to after the nap. However, there was no significant difference in physical exercise test results between the conditions for TTE (p = 0.367) or VO _2max (p = 0.308). Conclusions: Our results suggest that napping after light PSD does not significantly influence endurance performance. We conclude that aerobic performance is a multidimensional construct, and napping after PSD may not enhance it. However, napping is an effective method to increase wakefulness and vigilance, which can be beneficial for sports competitions. Full article

Integrative interpretation of cardiopulmonary exercise tests (CPETs) may improve assessment of cardiovascular (CV) risk. Here, we identified patient phenogroups based on CPET summary metrics and evaluated their predictive value for CV events. We included 2280 patients with diverse CV risk who underwent maximal CPET by cycle ergometry. Key CPET indices and information on incident CV events (median follow-up time: 5.3 years) were derived. Next, we applied unsupervised clustering by Gaussian Mixture modeling to subdivide the cohort into four male and four female phenogroups solely based on differences in CPET metrics. Ten of 18 CPET metrics were used for clustering as eight were removed due to high collinearity. In males and females, the phenogroups differed significantly in age, BMI, blood pressure, disease prevalence, medication intake and spirometry. In males, phenogroups 3 and 4 presented a significantly higher risk for incident CV events than phenogroup 1 (multivariable-adjusted hazard ratio: 1.51 and 2.19; p ≤ 0.048). In females, differences in the risk for future CV events between the phenogroups were not significant after adjustment for clinical covariables. Integrative CPET-based phenogrouping, thus, adequately stratified male patients according to CV risk. CPET phenomapping may facilitate comprehensive evaluation of CPET results and steer CV risk stratification and management. Full article

Background: Active exercise therapy plays an essential role in tackling the global burden of obesity. Optimizing recommendations in individual training therapy requires that the essential parameters heart rate HR(IAT) and work load (W/kg(IAT) at individual anaerobic threshold (IAT) are known. Performance diagnostics with blood lactate is one of the most established methods for these kinds of diagnostics, yet it is also time consuming and expensive. Methods: To establish a regression model which allows HR(IAT) and (W/kg(IAT) to be predicted without measuring blood lactate, a total of 1234 performance protocols with blood lactate in cycle ergometry were analyzed. Multiple linear regression analyses were performed to predict the essential parameters (HR(IAT)) (W/kg(IAT)) by using routine parameters for ergometry without blood lactate. Results: HR(IAT) can be predicted with an RMSE of 8.77 bpm (p < 0.001), R² = 0.799 (|R| = 0.798) without performing blood lactate diagnostics during cycle ergometry. In addition, it is possible to predict W/kg(IAT) with an RMSE (root mean square error) of 0.241 W/kg (p < 0.001), R² = 0.897 (|R| = 0.897). Conclusions: It is possible to predict essential parameters for training management without measuring blood lactate. This model can easily be used in preventive medicine and results in an inexpensive yet better training management of the general population, which is essential for public health. Full article

The aim of this study was to develop distributions of VO_2max based on measured values that exist in the literature in prepubertal boys using cycle ergometry. PRISMA guidelines were followed in conducting this research. One database was searched for peak and maximal VO₂ values in healthy boys with mean age under 11 years old. Data were split into articles reporting absolute and relative VO_2max values and analyzed accordingly. Multilevel models grounded in Bayesian principles were used. We investigated associations between VO_2max and body mass, year of the study, and country of origin. Differences in “peak” and “maximal” VO₂ were assessed. Absolute VO_2max (Lmin⁻¹) increases with age (P ~100%) but mean relative VO_2max does not change (P ~100%). Absolute VO_2max is higher in more recent studies (P = 95.7 ± 0.3%) and mean relative VO_2max is lower (P = 99.6 ± 0.1%). Relative VO_2max in the USA is lower compared with boys from other countries (P = 98.8 ± 0.2%), but there are no differences in absolute values. Mean aerobic capacity estimates presented as “peak” values are higher than “maximal” values on an absolute basis (P = 97.5 ± 0.3%) but not on a relative basis (P = 99.6 ± 0.1%). Heavier boys have lower cardiorespiratory fitness (P ≈ 100%), and body mass seems to be increasing faster with age in the USA compared with other countries (P = 92.3 ± 0.3%). New reference values for cardiorespiratory fitness are presented for prepubertal boys obtained with cycle ergometry. This is new, as no reference values have been determined so far based on actual measured values in prepubertal boys. Aerobic capacity normalized to body weight does not change with age. Cardiorespiratory fitness in prepubertal boys is declining, which is associated with increasing body mass over the last few decades. Lastly, this study did not find any statistically significant difference in the sample’s mean aerobic capacity estimates using the ”peak” and “maximum” distinctions identified in the literature. Full article

Models for predicting maximal oxygen consumption (VO_2max) in average adults might not be suitable for athletes, especially for competitive cyclists who can have significantly higher VO_2max than normally active people. The aim of this study was to develop a clinically applicable equation for predicting VO_2max during cycle ergometry in competitive cyclists and to compare its accuracy to the traditional American College of Sports Medicine (ACSM) equation. Maximal cycle ergometry tests were performed in 496 male and 84 female competitive cyclists. Six predictors were initially used to model the prediction equation (power output, body weight, body height, fat mass, fat-free mass and age). Power output and body weight were the most important parameters in the model predicting VO_2max. Three new equations were derived: for male (VO_2max = 0.10 × PO − 0.60 × BW + 64.21), female cyclists (0.13 × PO − 0.83 × BW + 64.02) and the non-gender-specific formula (0.12 × PO − 0.65 × BW + 59.78). The ACSM underestimated VO_2max in men by 7.32 mL/min/kg (11.54%), in women by 8.24 mL/min/kg (15.04%) and in all participants by 7.45 mL/min/kg (11.99%), compared to the new equation that underestimated VO_2max in men by 0.12 mL/min/kg (0.19%) and in all participants by 0.65 mL/min/kg (1.04%). In female cyclists, the new equation had no relative bias. We recommend that medicine and sports practitioners adapt our proposed equations when working with competitive cyclists. Our findings demonstrate the need to evaluate prediction models for other athletes with a special focus on disciplines that demand high aerobic capacity. Full article

Background: For optimal recommendations in cardiovascular training for the general population, knowing the essential parameters for physical fitness is required. Heart rate recovery (HRR) is an easy-to-measure parameter and is discussed to derive the physical fitness of an individual subject. This study evaluates HRR as a potential physical fitness parameter for public health programs, as it is measured in every ergometry. Methods: In this retrospective cross-sectional study, we analyzed HRR regarding physical fitness (W/kg (IAT: individual anaerobic threshold)). In total, we analyzed 1234 performance protocols in cycle ergometry. Significance tests (p < 0.001) and multiple linear regression were performed. Results: The analysis of HRR and weight-related performance showed a significant correlation with a moderate coefficient of determination (R² = 0.250). The coefficient of determination increases from very weak correlation levels at 1 min post-workout towards weak to moderate levels of correlation at 5 min post-workout. Conclusions: In this study HRR and the weight-related performance at the IAT showed a significant correlation with a mean strength. Thus, a prediction or conclusion on physical performance based singularly on HRR decrease is not recommended. However, in preventive medicine, HRR should be measured and observed on a long-term basis, for analysis of vagal activity and to draw to inferences of mortality. Full article

The aim of this study is to determine the magnitude of maximal fat oxidation (MFO) during incremental upper and lower body exercise. Thirteen non-specifically trained male participants (19.3 ± 0.5 y, 78.1 ± 9.1 kg body mass) volunteered for this repeated-measures study, which had received university ethics committee approval. Participants undertook two incremental arm crank (ACE) and cycle ergometry (CE) exercise tests to volitional exhaustion. The first test for each mode served as habituation. The second test was an individualised protocol, beginning at 40% of the peak power output (PO_peak) achieved in the first test, with increases of 10% PO_peak until volitional exhaustion. Expired gases were recorded at the end of each incremental stage, from which fat and carbohydrate oxidation rates were calculated. MFO was taken as the greatest fat oxidation value during incremental exercise and expressed relative to peak oxygen uptake (%$\dot{\mathit{V}}$O_2peak). MFO was lower during ACE (0.44 ± 0.24 g·min⁻¹) than CE (0.77 ± 0.31 g·min⁻¹; respectively, p < 0.01) and occurred at a lower exercise intensity (53 ± 21 vs. 67 ± 18%$\dot{\mathit{V}}$O_2peak; respectively, p < 0.01). Inter-participant variability for MFO was greatest during ACE. These results suggest that weight loss programs involving the upper body should occur at lower exercise intensities than for the lower body. Full article

Background: Inappropriate cycling positions may affect muscle usage strategy and raise the level of fatigue or risk of sport injury. Dynamic bike fitting is a growing trend meant to help cyclists select proper bikes and adjust them to fit their ergometry. The purpose of this study is to investigate how the “knee forward of foot” (KFOF) distance, an important dynamic bike fitting variable, influences the muscle activation, muscle usage strategy, and rate of energy expenditure during cycling. Methods: Six amateur cyclists were recruited to perform the short-distance ride test (SRT) and the graded exercise tests (GXT) with pedaling positions at four different KFOF distances (+20, 0, −20, and −40 mm). The surface electromyographic (EMG) and portable energy metabolism systems were used to monitor the muscle activation and energy expenditure. The outcome measures included the EMG root-mean-square (RMS) amplitudes of eight muscles in the lower extremity during the SRT, the regression line of the changes in the EMG RMS amplitude and median frequency (MF), and the heart rate and oxygen consumption during the GXT. Results: Our results revealed significant differences in the muscle activation of vastus lateralis, vastus medialis, and semitendinosus among four different pedaling positions during the SRT. During GXT, no statistically significant differences in muscle usage strategy and energy expenditure were found among different KFOF. However, most cyclists had the highest rate of energy expenditure with either KFOF at −40 mm or 20 mm. Conclusions: The KFOF distance altered muscle activation in the SRT; however, no significant influence on the muscle usage strategy was found in the GXT. A higher rate of energy expenditure in the extreme pedaling positions of KFOF was observed in most amateur cyclists, so professional assistance for proper bike fitting was recommended. Full article

Physical exercise has been shown to be effective in the treatment of non-communicable chronic diseases. However, patients with multiple chronic diseases (multimorbidity) have received little attention in health policy. This pilot trial served as a proof of concept of a 6-months person-oriented exercise intervention for people at risk of or with diagnosed cardiovascular diseases, diabetes mellitus type 2, overweight and/or hip/knee osteoarthritis, regarding effects on health outcomes as well as adherence and safety. The intervention (‘MultiPill-Exercise’) was designed to promote physical exercise participation, considering an individual perspective by addressing personal and environmental factors. Outcomes were assessed at baseline (t0) and after three- (t3) and six-months (t6). The primary outcome was self-reported physical exercise participation in minutes/week comparing t3 and t6 vs. t0. Secondary outcomes included cardio-respiratory fitness (maximum oxygen uptake VO₂peak during incremental cycling ergometry), isometric peak torque of knee extensors and flexors, health-related quality of life (Veterans Rand 12 with its subscales of perceived general health (GH), mental health (MCS), and physical health (PCS)) and blood levels. Adherence to exercise (% of attended sessions during the first 12-weeks of the intervention) and adverse events were monitored as well. Data were analyzed using a non-parametric procedure for longitudinal data, estimating rank means (M_Rank) and relative treatment effects (RTE) as well as linear-mixed effect models for parametric data. The primary endpoint of physical exercise participation was significantly higher at t3 and t6 compared to baseline (t3 vs. t0: M_Rank = 77.1, p < 0.001, RTE: 0.66; t6 vs. t0: M_Rank = 70.6, p < 0.001, RTE = 0.60). Improvements at both follow-up time points compared to t0 were also found for relative VO₂peak (t3 vs. t0 = 2.6 mL/kg/min, p < 0.001; t6 vs. t0 = 2.0 mL/kg/min, p = 0.001), strength of knee extensors (t3 vs. t0 = 11.7 Nm, p = 0.007; t6 vs. t0= 18.1 Nm, p < 0.001) and GH (t3 vs. t0 = 16.2, p = 0.003; t6 vs. t0 = 13.4, p = 0.008). No changes were found for MCS, PCS and for blood levels. Overall exercise adherence was 77%. No serious adverse events were recorded. Results of this pilot trial represent a first proof of concept for the intervention ‘MultiPill-Exercise’ that will now be implemented and evaluated in a real-world health care setting. Full article