The concurrent validity and test-retest reliability of a submaximal exercise test in adolescents with autism.

PURPOSE: There is a need for valid and reliable clinical assessment tools to assess cardiorespiratory fitness (CRF) levels in adolescents with autism. Therefore, this study aimed to examine the concurrent validity and test-retest reliability of the Astrand-Rhyming Test (ART) in this population. MATERIALS AND METHODS: 45 adolescents with autism aged 12-18 years (n = 32 males, 14.47 ± 1.79 years) performed the ART twice (test-retest reliability) and completed a maximal cardiopulmonary exercise test (CPET) (concurrent validity). Reliability parameters included Pearson correlations, intraclass correlation coefficients (ICCs), standard error of measurements (SEM), minimal detectable changes (MDC), coefficients of variation, paired sample t-tests, linear regressions and Bland-Altman plots. The concurrent validity was evaluated with Pearson correlations, ICCs, paired sample t-tests, linear regressions and Bland-Altman plots. RESULTS: Strong test-retest reliability (r = 0.84-0.85, ICC = 0.84-0.85) was found for the ART, but the wide limits of agreement intervals suggest the presence of substantial variability. The large SEM (4.73-5.08 mL/kg/min) and MDC (13.20-14.07 mL/kg/min) values suggest lower absolute reliability. Moderate to strong levels of association (r = 0.74-0.75) and agreement (ICC = 0.59-0.66) were found between estimated (ART1) and measured (CPET) VO2 max levels, but significant systematic differences (5.71-8.82 mL/kg/min) were observed. CONCLUSION: The ART is an accessible and promising method to monitor submaximal CRF levels over time but is less appropriate to estimate maximal CRF levels in this population.

Adolescents with autism are at increased risk of exhibiting low cardiorespiratory fitness (CRF) levels and as a result, placing them at risk for poor physical and mental health outcomes.In clinical practice, the CRF levels of this population should be screened and monitored routinely to identify those at risk and most likely to benefit from a targeted intervention.A submaximal exercise test appears to be feasible in adolescents with autism.The Astrand-Rhyming Test shows good reliability to monitor submaximal CRF levels over time, but is less appropriate to estimate maximal CRF levels in adolescents with autism.The use of the age correction factor of the Astrand-Rhyming Test nomogram is not required to adequately estimate CRF levels in adolescents with autism.

Cardiopulmonary Exercise Testing after Surgical Repair of Tetralogy of Fallot-Does Modality Matter?

BACKGROUND: Despite a successful repair of tetralogy of Fallot (rToF) in childhood, residual lesions are common and can contribute to impaired exercise capacity. Although both cycle ergometer and treadmill protocols are often used interchangeably these approaches have not been directly compared. In this study we examined cardiopulmonary exercise test (CPET) measurements in rToF. METHODS: Inclusion criteria were clinically stable rToF patients able to perform a cardiac magnetic resonance imaging (CMR) and two CPET studies, one on the treadmill (incremental Bruce protocol) and one on the cycle ergometer (ramped protocol), within 12 months. Demographic, surgical and clinical data; functional class; QRS duration; CMR measures; CPET data and international physical activity questionnaire (IPAQ) scores of patients were collected. RESULTS: Fifty-seven patients were enrolled (53% male, 20.5 ± 7.8 years at CPET). CMR measurements included a right ventricle (RV) end-diastolic volume index of 119 ± 22 mL/m2, a RV ejection fraction (EF) of 55 ± 6% and a left ventricular (LV) EF of 56 ± 5%. Peak oxygen consumption (VO2)/Kg (25.5 ± 5.5 vs. 31.7 ± 6.9; p < 0.0001), VO2 at anaerobic threshold (AT) (15.3 ± 3.9 vs. 22.0 ± 4.5; p < 0.0001), peak O2 pulse (10.6 ± 3.0 vs. 12.1± 3.4; p = 0.0061) and oxygen uptake efficiency slope (OUES) (1932.2 ± 623.6 vs. 2292.0 ± 639.4; p < 0.001) were significantly lower on the cycle ergometer compared with the treadmill, differently from ventilatory efficiency (VE/VCO2) max which was significantly higher on the cycle ergometer (32.2 ± 4.5 vs. 30.4 ± 5.4; p < 0.001). Only the VE/VCO2 slope at the respiratory compensation point (RCP) was similar between the two methodologies (p = 0.150). CONCLUSIONS: The majority of CPET measurements differed according to the modality of testing, with the exception being the VE/VCO2 slope at RCP. Our data suggest that CPET parameters should be interpreted according to test type; however, these findings should be validated in larger populations and in a variety of institutions.

Comprehensive evaluation of efficiency to identify deficiencies in muscle activity in different modes in team sports.

OBJECTIVE: Aim: To concern the scientific substantiation of a complex ergometer tests of aerobic and anaerobic character and quantitative criteria for assessing the condition of female handball players` respiratory and power supply systems in the maximum. PATIENTS AND METHODS: Materials and Methods: Descriptive analysis, correlation analysis, factor analysis. In order to solve those tasks within the framework there were measured the indicators of two hundred young female handball players at the pre-basic training stage. RESULTS: Results: The outcomes of the research allow us to recommend the program for handball players` potential capabilities assessment that will help to characterize the state of power supply systems of the body under aerobic and anaerobic conditions. At the same time, the results of the testing can be used to identify strengths and weaknesses in the structure of handball players` special readiness indicators and to individualize the process of players' preparation at the subsequent stages. CONCLUSION: Conclusions: As a result of experimental data, the quantitative criteria and the scale for the assessment of handball players' working capacity in ergometer maximum tests of aerobic-anaerobic character have been developed. On the basis of these tests, it is possible to analyze objectively the individual characteristics of children before making a final decision.

Quantitative assessment of muscle fatigue during rowing ergometer exercise using wavelet analysis of surface electromyography (sEMG).

In this paper, we present a quantitative assessment of muscle fatigue using surface electromyography (sEMG), a widely recognized method that is conducted through various analytical approaches, including analysis of spectral and time-frequency distributions. Existing research in this field has demonstrated considerable variability in the computational methods used. Although some studies highlight the efficacy of wavelet analysis in dynamic motion, few offer a comprehensive method for determining fatigue and applying it to specific movements. Previous research has focused primarily on discerning differences based on sport type or gender, with a notable absence of studies that presented results for quantifying fatigue during exercise with rowing ergometers. Developing on our previous work, where we introduced a method for determining muscle fatigue through wavelet analysis, considering biomechanical aspects of limb position changes, this current article serves as a continuation. Our study refines the research approach for a selected group, focusing on fatigue determination using the previously established method. The results obtained confirm the effectiveness of DWT analysis in assessing muscle fatigue, as evidenced by the achievement of negative values of the regression coefficients of Median Frequency (MDF) during exercises performed to maximal fatigue. Furthermore, it has been confirmed that the homogeneity of the group and, in the case of the examined group, the results previously achieved or lower limb strength do not have an impact on the results. Finally, we discuss the main limitations of our study and outline the subsequent steps of our investigation, providing valuable information for future investigations in this field.

Oxygen uptake during the last bouts of exercise incorporated into high-intensity intermittent cross-exercise exceeds the V˙ O2max of the same exercise mode.

Oxygen uptake (V˙ O2) was measured during a non-exhaustive high-intensity intermittent cross-exercise (HIICE) protocol consisting of four alternating bouts of 20 â€‹s running (R) and three bouts of bicycle exercise (BE) at ∼160% and ∼170% maximal oxygen uptake (V˙ O2max), respectively, with 10 â€‹s between-bout rests (sequence R-BE-R-BE-R-BE-R). The V˙ O2 during the last BE ([52.2 â€‹± â€‹5.0] mL·kg-1·min-1) was significantly higher than the V˙ O2max of the BE ([48.0 â€‹± â€‹5.4] mL·kg-1·min-1, n â€‹= â€‹30) and similar to that of running. For clarifying the underlying mechanisms, a corresponding HIICE-protocol with BE and arm cranking ergometer exercise (AC) was used (sequence AC-AC-BE-AC-BE-AC-AC-BE). In some experiments, thigh blood flow was occluded by a cuff around the upper thigh. Without occlusion, the V˙ O2 during the AC ([39.2 â€‹± â€‹7.1] mL·kg-1·min-1 [6th bout]) was significantly higher than the V˙ O2max of AC ([30.2 â€‹± â€‹4.4] mL·kg-1·min-1, n â€‹= â€‹7). With occlusion, the corresponding V˙ O2 ([29.8 â€‹± â€‹3.9] mL·kg-1·min-1) was reduced to that of the V˙ O2max of AC and significantly less than the V˙ O2 without occlusion. These findings suggest that during the last bouts of HIICE may exceed the of the specific exercise, probably because it is a summation of the V˙ O2 for the ongoing exercise plus excess post-oxygen consumption (EPOC) produced by the previous exercise with a higher V˙ O2max.

Validation of LEOMO inertial measurement unit sensors with marker-based three-dimensional motion capture during maximum sprinting in track cyclists.

LEOMO™ is a commercial inertial measurement unit system that provides cycling-specific motion performance indicators (MPIs) and offers a mobile solution for monitoring cyclists. We aimed to validate the LEOMO sensors during sprint cycling using gold-standard marker-based three-dimensional (3D) motion technology (Qualisys, AB). Our secondary aim was to explore the relationship between peak power during sprints and MPIs. Seventeen elite track cyclists performed 3 × 15s seated start maximum efforts on a cycle ergometer. Based on intraclass correlation coefficient (ICC3,1), the MPIs derived from 3D and LEOMO showed moderate agreement (0.50 < 0.75) for the right foot angular range (FAR); left foot angular range first quadrant (FARQ1); right leg angular range (LAR); and mean angle of the pelvis in the sagittal plane. Agreement was poor (ICC < 0.50) between MPIs derived from 3D and LEOMO for the left FAR, right FARQ1, left LAR, and mean range of motion of the pelvis in the frontal and transverse planes. Only one LEOMO-derived (pelvic rotation) and two 3D-derived (right FARQ1 and FAR) MPIs showed large positive significant correlations with peak power. Caution is advised regarding use of the LEOMO for short maximal cycling efforts and derived MPIs to inform peak sprint cycling power production.

Reliability and validity of a non-linear index of heart rate variability to determine intensity thresholds.

Exercise intensity distribution is crucial for exercise individualization, prescription, and monitoring. As traditional methods to determine intensity thresholds present limitations, heart rate variability (HRV) using DFA a1 has been proposed as a biomarker for exercise intensity distribution. This index has been associated with ventilatory and lactate thresholds in previous literature. This study aims to assess DFA a1's reliability and validity in determining intensity thresholds during an incremental cycling test in untrained healthy adults. Sixteen volunteers (13 males and 3 females) performed two identical incremental cycling stage tests at least 1 week apart. First and second ventilatory thresholds, lactate thresholds, and HRV thresholds (DFA a1 values of 0.75 and 0.5 for HRVT1 and HRVT2, respectively) were determined in heart rate (HR), relative oxygen uptake (VO2rel), and power output (PO) values for both tests. We used intraclass correlation coefficient (ICC), change in mean, and typical error for the reliability analysis, and paired t-tests, correlation coefficients, ICC, and Bland-Altman analysis to assess the agreement between methods. Regarding reliability, HRV thresholds showed the best ICCs when measured in PO (HRVT1: ICC = .87; HRVT2: ICC = .97), comparable to ventilatory and lactate methods. HRVT1 showed the strongest agreement with LA 2.5 in PO (p = 0.09, r = .93, ICC = .93, bias = 9.9 ± 21.1), while HRVT2 reported it with VT2 in PO (p = 0.367, r = .92, ICC = .92, bias = 5.3 ± 21.9). DFA a1 method using 0.75 and 0.5 values is reliable and valid to determine HRV thresholds in this population, especially in PO values.

Rowing and pain: does rowing lead to exercise-induced hypoalgesia?

Physical activity acutely alters pain processing known as exercise-induced hypoalgesia (EIH). This randomized controlled crossover study investigated the effects of two different rowing exercises on EIH and to explore whether possible EIH effects are related to individual rowing specific performance. Fifty male experienced rowers conducted two rowing sessions (submaximal: 30 min of moderate rowing (70% of maximum heart rate); maximal: 350 m in an all-out fashion) and a control session. Pre and post exercise pain sensitivity was measured bilaterally using pressure pain thresholds (PPT; Newton (N)) at the elbow, knee, ankle, sternum, and forehead. Individual performance was determined as maximum watt/kg and was tested for correlations with changes in PPT. Higher PPT values were observed after maximal exercise at all landmarks with a mean change ranging from 2.5 ± 7.8 N (right elbow; p = 0.027; dz = 0.323) to 10.0 ± 12.2 N (left knee; p ≤ 0.001; dz = 0.818). The submaximal (range from -1.6 ± 8.8 N (Sternum; p = 0.205; dz = 0.182) to 2.0 ± 10.3 N (right ankle; p = 0.176; dz = 0.194)) and control session (range from -0.5 ± 7.6 N (left elbow; p = 0.627; dz = 0.069) to 2.6 ± 9.1 N (right ankle; p = 0.054; dz = 0.279)) did not induce changes. Relative performance levels were not correlated to EIH (range from: r = -0.129 (p = 0.373) at sternum to r = 0.176 (p = 0.221) at left knee). EIH occurred globally after a short maximal rowing exercise while no effects occurred after rowing for 30 min at submaximal intensity. EIH cannot be explained by rowing specific performance levels in experienced rowers. However, the sample may lack sufficient heterogeneity in performance levels to draw final conclusions.

Effect of Floss Band on Anaerobic Exercise and Muscle Tissue Oxygenation.

CONTEXT: Flossing is still a relatively new technique that has yielded varied results in the research literature; therefore, it requires further investigation. Previous research has shown that thigh tissue flossing might improve performance in countermovement jump, sprint time, maximum voluntary contraction, and rate of force development. DESIGN: The present study aims to investigate the effect of the floss band on performance during the Wingate test (30-WAT), muscle oxygen saturation (SpO2), and total hemoglobin in vastus lateralis. METHODS: Twenty-two students of physical education and sport (11 men and 11 women) were randomly selected to complete either the Wingate test with the application of a floss band in warm-up or the Wingate test without the use of a floss band, followed by the alternative 24 hours apart. RESULTS: Throughout the testing, the floss band did not affect performance values during the Wingate test (relative peak power, relative average power, and fatigue index). However, there was a medium to large effect difference during 1 minute prior to 30-WAT (PRE), during the 30-WAT, and 10-minute recovery (REC) in values of SpO2 and total hemoglobin. Use of floss band displayed a higher SpO2 during PRE, 30-WAT, and REC by ∼13.55%, d < 2; ∼19.06%, d = 0.89; and ∼8.55%, d = 0.59, respectively. CONCLUSION: Collectively, these findings indicate that the application of thigh flossing during warm-up has no effect on 30-WAT performance; however, SpO2 was significantly increased in all stages of testing. This could lead to potential improvement in repeated anaerobic exercise due to increased blood flow. Increased muscle oxygen saturation can also lead to improved tissue healing as oxygen supply is essential for tissue repair, wound healing, and pain management.

Effect of Bicycle Ergometer Training and Nordic Walking Training on Improving Functional Exercise Capacity in Asthma Patients.

Introduction Asthma is a chronic respiratory condition characterized by inflammation of the airway leading to breathlessness. Exercise training has been recognized as a valuable component in the management of asthma, enhancing lung function and overall well-being. Bicycle ergometer training and Nordic walking are two distinct forms of exercise that have been shown to improve cardiovascular fitness and respiratory function. Despite the potential benefits of these exercises, limited research directly compares their efficacy in improving functional capacity specifically in asthma patients. The study thus aims to address this gap by providing personalized, tailored exercise programs for asthma patients. Methods A single-blinded experimental study using a simple random sampling method was conducted. A sample of 40 subjects was recruited for the study based on inclusion and exclusion criteria and were assigned into two groups. Group A subjects were trained with a bicycle ergometer and Group B subjects were trained with Nordic walking. The intervention was given to both groups for 12 weeks. The outcome measures used were the six-minute walk test, Modified Borg Scale, and Mini Asthma Quality of Life Questionnaire. Results A baseline analysis of outcome measures was done, which was followed up by a post-test analysis after 12 weeks. Pre-test and post-test data were compared using a paired t-test. Intergroup analysis was done by an independent t-test. Both groups showed significant improvement in post-test results. On comparing the two groups, Group A showed significant improvement as compared to Group B. Conclusion The study concludes that bicycle ergometer training is effective in improving functional capacity and enhancing the quality of life in asthma patients.

Physiological and perceptual responses to acute arm cranking with blood flow restriction.

INTRODUCTION: Lower-body aerobic exercise with blood flow restriction (BFR) offers a unique approach for stimulating improvements in muscular function and aerobic capacity. While there are more than 40 reports documenting acute and chronic responses to lower-body aerobic exercise with BFR, responses to upper-body aerobic exercise with BFR are not clearly established. PURPOSE: We evaluated acute physiological and perceptual responses to arm cranking with and without BFR. METHODS: Participants (N = 10) completed 4 arm cranking (6 × 2 min exercise, 1 min recovery) conditions: low-intensity at 40%VO2peak (LI), low-intensity at 40%VO2peak with BFR at 50% of arterial occlusion pressure (BFR50), low-intensity at 40%VO2peak with BFR at 70% of arterial occlusion pressure (BFR70), and high-intensity at 80%VO2peak (HI) while tissue oxygenation, cardiorespiratory, and perceptual responses were assessed. RESULTS: During exercise, tissue saturation for BFR50 (54 ± 6%), BFR70 (55 ± 6%), and HI (54 ± 8%) decreased compared to LI (61 ± 5%, all P < 0.01) and changes in deoxyhemoglobin for BFR50 (11 ± 4), BFR70 (15 ± 6), and HI (16 ± 10) increased compared to LI (4 ± 2, all P < 0.01). During recovery intervals, tissue saturation for BFR50 and BFR70 decreased further and deoxyhemoglobin for BFR50 and BFR70 increased further (all P < 0.04). Heart rate for BFR70 and HI increased by 9 ± 9 and 50 ± 15b/min, respectively, compared to LI (both P < 0.02). BFR50 (8 ± 2, 1.0 ± 1.0) and BFR70 (10 ± 2, 2.1 ± 1.4) elicited greater arm-specific perceived exertion (6-20 scale) and pain (0-10 scale) compared to LI (7 ± 1, 0.2 ± 0.5, all P < 0.05) and pain for BFR70 did not differ from HI (1.7 ± 1.9). CONCLUSION: Arm cranking with BFR decreased tissue saturation and increased deoxyhemoglobin without causing excessive cardiorespiratory strain and pain.

Validation of the maximal cardiopulmonary exercise test in adolescents with major depressive disorder and comparison of cardiorespiratory fitness with sex- and age-related control values.

Endurance training has been shown to be effective in treating adolescents with major depressive disorder (MDD). To integrate endurance training into the therapeutic setting and the adolescents' daily lives, the current performance status of the adolescents should be accurately assessed. This study aims to examine adolescents with MDD concerning exhaustion criteria during a cardiopulmonary exercise test (CPET), as well as to compare the values obtained thereon with sex- and age-related control values. The study included a retrospective examination of exhaustion criteria ((i) oxygen consumption (V̇O2) plateau, (ii) peak respiratory exchange ratio (RERpeak) > 1.0, (iii) peak heart rate (HRpeak) ≥ 95% of the age-predicted maximal HR, and (iv) peak blood lactate concentration (BLCpeak) > 8.0 mmol⋅L-1) during a graded CPET on a cycle ergometer in adolescents with MDD (n = 57). Subsequently, maximal V̇O2, peak minute ventilation, V̇O2 at the first ventilatory threshold, and peak work rate of participants who met at least two of four criteria were compared with published control values using an independent-sample t-test. Thirty-three percent of the total population achieved a V̇O2 plateau and 75% a RERpeak > 1.0. The HR and BLC criteria were met by 19% and 22%, respectively. T-test results revealed significant differences between adolescents with MDD and control values for all outcomes. Adolescents with MDD achieved between 56% and 83% of control values.   Conclusions: The study shows that compared with control values, fewer adolescents with MDD achieve the exhaustion criteria on a CPET and adolescents with MDD have significantly lower cardiorespiratory fitness.   Clinical trial registration: No. U1111-1145-1854. What is Known: • It is already known that endurance training has a positive effect on depressive symptoms. What is New: • A relevant proportion of adolescents with major depressive disorder do not achieve their V̇O2max during a graded cardiopulmonary exercise test. • Adolescents with major depressive disorder have significantly lower cardiorespiratory fitness compared to sex- and age-related control values.

Comparison of Cardiovascular Response to Lower Body and Whole Body Exercise Among Sedentary Young Adults.

Background Cardiovascular responses to exercise are essential indicators of cardiovascular health and fitness. Understanding how different types of exercise, such as lower-body and whole-body exercises, impact these responses is crucial for designing effective fitness programs and assessing cardiovascular function. Aim This study aimed to compare the cardiovascular response of young adults during lower-body exercise using a bicycle ergometer and whole-body exercise on a treadmill. Methods Thirty-two healthy young adults participated in this study. Each participant completed two exercise sessions on separate days: lower-body exercise on a bicycle ergometer with a fixed cadence of 60 rpm with a breaking resistance of 1.75 kg and whole-body exercise on a treadmill with a speed of 1.7 mph and a 10% grade. Heart rate (HR), systolic blood pressure (BP), and diastolic BP were measured at rest and immediately after a three-minute exercise. Data were analyzed using paired t-tests to compare the cardiovascular responses between the two exercise modalities. Results A total of 17 male and 15 female young adults with a mean age of 20.87±1.43 years participated in the study. The male and female participants had similar ages (p =0.56) and body mass indexes (p = 0.1). There was a higher HR (129.16±2.67 versus 150.87±3.23, p<0.0001) and systolic BP (127.29±2.34 versus 144.9±4.16, p<0.0001) and lower diastolic BP (68.97±2.41 versus 62.97±2.31, p<0.0001) in whole body exercise on treadmill compared to lower body exercise in bicycle ergometer. The effect size was large enough as Cohen's d was 7.33, 5.13, and 2.54 for HR, systolic BP, and diastolic BP, respectively. Conclusion In sedentary young adults, treadmill exercise led to higher HR, systolic BP, and lower diastolic BP than bicycle ergometer exercise. Increased muscle recruitment might result in higher energy expenditure, increasing the HR and systolic BP to deliver oxygen and nutrients to the working muscles. Further research is needed to understand the mechanisms and long-term implications for precise exercise recommendations and better cardiovascular health management.

Sympathovagal Balance and Body Shape Index in Elite and Amateur Athletes: The Relationship Unraveled.

Background Heart rate variability (HRV) is one piece among a complex network of adaptations existent in athletes that help them gain a better understanding of their own physiology. Sympathovagal balance is one of the spectral components of HRV analysis and is used to assess the frequently changing oscillations of a healthy heart, which can help in gauging the response of cardiac function towards physiological stress during exercise. This index is extensively used in appraising cardiac autonomic modulation. An evaluation of body composition in athletes has become a critical consideration when tracking HRV, as it helps practitioners understand the role of the autonomic nervous system (ANS) in obesity. The body shape index (BSI), which is based on waist circumference (WC), is an anthropometric parameter with decent predictive ability when measuring centripetal obesity. In this regard, the current study is an attempt to unravel the relationship between BSI and sympathovagal balance during exercise performed on two different instruments (treadmill and ergometer) by elite and amateur athletes. Methods It was an observational case-control study that included 30 elite and 120 amateur athletes. Symptom-limited exercise testing was performed by athletes on a motorized treadmill and ergometer in the sports physiology laboratory of a rural medical college in central India. Different anthropometric parameters like BSI and body surface area (BSA) were also recorded. Short-term HRV extracted from electrocardiogram (ECG) recordings was obtained using the Power Lab system and HRV analysis by LabChart software. Results The sympathovagal ratio, i.e., ratio of low frequency (LF) to high frequency (HF) in elite and amateur male populations showed a higher value than that in females, indicating a dominant sympathetic response in the males. There was a significant (p=0.042) positive correlation (r=0.24) between BSI and LF/HF Ratio in amateur females during treadmill exercise, whereas a significant (p=0.049) negative correlation (r=-0.27) was obtained in amateur males during ergometer exercise. Hence, increased weight and BSI were found to be associated with high sympathetic dominance, indicating a sympathovagal imbalance. Conclusion We attempted to explore the interaction between BSI and LF/HF during exercise performed on two different instruments (treadmill and ergometer) by elite and amateur athletes, which can help in testing the response of cardiac function to stress experienced during exercise. The study's uniqueness stems from discovering the relationship between BSI and HRV and how this relationship impacts sports performance. BSI measurement in athletes, both elite and amateur, allows for the assessment and forecasting of potential autonomic activity under exercise-induced stress by linking HRV with BSI.

Technical note: MR-compatible pedal ergometer with electromechanical pedal resistance and exercise triggering enhanced by visual feedback via video display.

BACKGROUND: During and after exercise, dynamic 31 P MR parameters are typically measured using an MR-compatible ergometer. Self-built equipment for local condition can be constructed where possible. PURPOSE: To develop a pedal resistance ergometer with rocker arm based on a system that combines electric weight displacement, visual self-monitoring, and exercise triggering. The repeatability and reproducibility were tested. METHODS: The hardware and software for the ergometer were constructed from commercial components in a home laboratory. Twelve volunteers participated in the testing of the ergometer. RESULTS: A fully automated ergometer system was developed, allowing the pedal resistance to be adjusted during the examination. The system includes a self-monitoring and triggering mechanism that enables both the operator and subject to monitor pedal frequency and force. The operator can modify the pedal resistance as desired during the exercise. This self-monitoring solution is simple and cost-effective, requiring only a commercial potentiometer, an Arduino converter, and a conventional video projector with a personal computer (PC). Additionally, all system components are located outside the magnetic resonance (MR) room, avoiding interference with the MR system. Results of several test of the reproducibility/repeatability of power at three pedal resistance values (15%, 24%, 25% maximal voluntary force) were expressed both as a coefficient of variation ranging from 6% to 3.1% and as an intraclass correlation of coefficient ranging from 0.96 to 0.99. Similar values were also found for other dynamic parameters of 31 P MR spectroscopy. These findings are similar to published data obtained on different types of ergometers. CONCLUSIONS: Based on more than 1 year of usage, the ergometer proved successful in handling stationary and variable loads, and can be easily operated by a single user.

Development and validation of dynamic bioenergetic model for intermittent ergometer cycling.

PURPOSE: The aim of this study was to develop and validate a bioenergetic model describing the dynamic behavior of the alactic, lactic, and aerobic metabolic energy supply systems as well as different sources of the total metabolic energy demand. METHODS: The bioenergetic supply model consisted of terms for the alactic, lactic, and aerobic system metabolic rates while the demand model consisted of terms for the corresponding metabolic rates of principal cycling work, pulmonary ventilation, and accumulated metabolites. The bioenergetic model was formulated as a system of differential equations and model parameters were estimated by a non-linear grey-box approach, utilizing power output and aerobic metabolic rate (MRae) data from fourteen cyclists performing an experimental trial (P2) on a cycle ergometer. Validity was assessed by comparing model simulation and measurements on a similar follow-up experimental trial (P3). RESULTS: The root mean square error between modelled and measured MRae was 61.9 ± 7.9 W and 79.2 ± 30.5 W for P2 and P3, respectively. The corresponding mean absolute percentage error was 8.6 ± 1.5% and 10.6 ± 3.3% for P2 and P3, respectively. CONCLUSION: The validation of the model showed excellent overall agreement between measured and modeled MRae during intermittent cycling by well-trained male cyclist. However, the standard deviation was 38.5% of the average root mean square error for P3, indicating not as good reliability.

The Effects of Incorporating Dry-land Short Intervals to Long Aerobic-dominant In-Water Swimming Training on Physiological Parameters, Hormonal Factors, and Performance: A Randomized-Controlled Intervention Study.

This study investigated the impact of a 4-week dry-land short sprint interval program (sSIT) on a swim ergometer, when incorporated into long aerobic-dominant in-water swimming training, on the physiological parameters, hormonal factors, and swimming performance of well-trained swimmers. Sixteen participants (age = 25 ± 6 years, height = 183 ± 6 cm, weight 78 ± 6 kg, body fat = 10.6 ± 3.1%) were randomized to either a long aerobic-dominant in-pool training plus three sessions/week of sSIT or a control group (CON) who didn't engage in SIT. sSIT consisted of 3 sets of 10 × 4 s, 10 × 6 s, and 10 × 8 s all-out sprints interspersed by 15, 60, and 40 s recovery between each sprint, respectively. Pre- and post-training assessments included peak oxygen uptake (V̇O2peak), O2pulse (V̇O2/HR), ventilation at V̇O2peak (V̇E@V̇O2peak), peak and average power output, and freestyle swim performance at 50, 100, and 200-m distances, stroke rate, as well as testosterone and cortisol. sSIT resulted in significant improvements in V̇O2peak (5.8%), O2pulse (4.7%), V̇E@V̇O2peak (7.1%), peak and average power output (6.7% and 13.8%, respectively), total testosterone (20%), testosterone to cortisol ratio (16.1%), and 50, 100, and 200-m freestyle swimming performance (-2.2%, -1.2%, and -1.1%, respectively). Furthermore, the observed alterations in the physiological, biochemical, and performance adaptations were significantly more substantial in the sSIT group than the CON group (p ≤ 0.05), demonstrating no modifications during the 4-week long aerobic-dominant in-water swimming without sSIT. The current research effectively established that supplementing standard long aerobic-dominant in-water swim training with three weekly dry-land sSIT sessions triggers adaptive mechanisms that foster enhancements in the aerobic and anaerobic capacity and swimming performance in well-trained swimmers.

Effect of Cycling Exercise Resisting Electrically Stimulated Antagonist Muscle Contractions in Healthy Males.

A hybrid training system (HTS) combining antagonist muscle electrical stimulation and voluntary muscle contraction has been developed using eccentric antagonist muscle contractions with electrical stimulation as resistance to voluntary muscle contractions. We devised an exercise method using HTS combined with a cycle ergometer (HCE). The purpose of this study was to compare the muscle strength, muscle volume, aerobic functions and lactate metabolism of HCE and a volitional cycle ergometer (VCE). A total of 14 male participants performed exercise on a bicycle ergometer for 30 min per session, 3 times per week for 6 weeks. We divided 14 participants into an HCE group (7 participants) and a VCE group (7 participants). The workload was set at 40% of each participant's peak oxygen uptake (V.O2peak). Electrodes were placed over each motor point on the quadriceps and hamstrings. The V.O2peak and anaerobic threshold significantly increased before and after training when using HCE rather than VCE. The HCE group had significantly increased extension and flexion muscle strength at 180 degrees/s in post-training measurements over pre-training measurements. Knee flexion muscle strength at 180 degrees/s tended to increase in the HCE group compared to the VCE group. The quadricep muscle cross-sectional area was significantly increased in the HCE group compared to the VCE group. Additionally, the HCE group had significantly decreased maximal lactate, measured every 5 min during exercise at the end of study, between pre and post-training. Thus, HCE may be a more effective training method for muscle strength, muscle mass and aerobic functions at 40% of each participant's V.O2peak than conventional cycling exercise. HCE could be applied not only as aerobic exercise but also as resistance training.

Cardiorespiratory Fitness in Young Adult Women With a History of Premature Adrenarche.

Context: Premature adrenarche (PA) may predispose to some adverse long-term health outcomes. Cardiorespiratory fitness (CRF) is one of the strongest factors known to predict overall health, but no data exist on the CRF of women with a history of PA. Objective: To study if hyperandrogenism in childhood resulting from PA leads to a measurable difference in CRF between young adult PA and control women. Methods: A total of 25 women with PA and 36 age-matched controls were followed from prepubertal age until adulthood. Anthropometric measurements, body composition, biochemical, and lifestyle factors were assessed. The main outcome measure was maximal cycle ergometer test result at the mean age of 18.5 years. We also assessed prepubertal predicting factors for CRF with different linear regression models. Results: Though prepubertal children with PA were taller and heavier than their non-PA peers, there were no significant differences in height, body mass index, body composition, or physical activity in young adulthood. We observed no significant differences in any of the parameters of the maximal cycle ergometer test, including maximal load (P = .194) or peak oxygen consumption (P = .340). Hemodynamic responses of the groups were similar. None of the examined models or prepubertal factors significantly predicted CRF at adult age. Conclusion: This study suggests that hyperandrogenism in childhood/adolescence resulting from PA does not have a significant impact on adulthood CRF.

ICEP: An Instrumented Cycling Ergometer Platform for the Assessment of Advanced FES Strategies.

BACKGROUND: Functional electrical stimulation (FES) cycling has seen an upsurge in interest over the last decade. The present study describes the novel instrumented cycling ergometer platform designed to assess the efficiency of electrical stimulation strategies. The capabilities of the platform are showcased in an example determining the adequate stimulation patterns for reproducing a cycling movement of the paralyzed legs of a spinal cord injury (SCI) subject. METHODS: Two procedures have been followed to determine the stimulation patterns: (1) using the EMG recordings of the able-bodied subject; (2) using the recordings of the forces produced by the SCI subject's stimulated muscles. RESULTS: the stimulation pattern derived from the SCI subject's force output was found to produce 14% more power than the EMG-derived stimulation pattern. CONCLUSIONS: the cycling platform proved useful for determining and assessing stimulation patterns, and it can be used to further investigate advanced stimulation strategies.