Ventilatory Breakpoint Research Articles

A normalized rate of perceived exertion at ventilatory breakpoint for different exercise modalities and production of exercise intensity with self-regulation for Singapore children.

The purpose of this study was to identify a normalized RPE response at ventilatory breakpoint (V<inf>pt</inf>) for male adolescents 13-17 years old, and whether these adolescents could self-regulate at target RPEs of 4 and 6. Twenty healthy males participated in the study, with 10 males in each of the cycling and walking/running groups. Participants performed orientation and V̇O<inf>2peak</inf> trials before performing a perceptual estimation exercise trial to obtain RPE V<inf>pt</inf>, and two production trials to assess self-regulation ability. V<inf>pt</inf> corresponded to 67.7% V̇O<inf>2peak</inf> for the cycling group and 70.4% V̇O<inf>2peak</inf> for the walking/running group. There were no group differences on RPE-Overall V<inf>pt</inf> (cycling: 4.6; walking/running: 4.4), RPE-Legs V<inf>pt</inf> (cycling: 5.4; walking/running: 4.6), and RPE-Chest V<inf>pt</inf> (cycling: 4.0; walking/running: 4.8). A normalized RPE-Overall V<inf>pt</inf> response was identified at five. V̇O<inf>2</inf> did not differ between the estimation and production trials at targets RPE of 4 (1.59 vs. 1.57 L·min-1) and 6 (1.87 vs. 1.79 L·min-1). Similarly, heart rate (HR) did not differ between estimation and production trials at targets RPE 4 (152.4 vs. 151.1 beats·min-1) and 6 (167.1 vs. 162.4 beats·min-1). Both V̇O<inf>2</inf> and HR were significantly higher at RPE 6 compared to RPE 4. Responses were not affected by exercise mode or production sequence. This study demonstrated that undifferentiated and differentiated RPE V<inf>pt</inf> were similar between cycling and walking/running participants. Male adolescents between 13- and 17-year-olds were able to use the OMNI scale to self-regulate exercise intensities that would be useful in field settings.

Predictors of 2 Kilometer Rowing Ergometer Time Trial Performance

Predictors of performance can aid coaches and trainers in prescribing exercise programs for rowing athletes. To date, most of the prediction models have been developed for runners and cyclists. PURPOSE: The aim of this study was to develop a regression model to predict performance of a simulated 2 kilometer rowing ergometer time trial. METHODS: A group of mixed gender rowing athletes (n=12) completed in a counterbalanced order a 2 Kilometer rowing time trial and a continuous progressively incremented graded exercise test on a rowing ergometer. Subjects were 23.91±4.99 years old, weighed 79.14±12.85 kg, were 187.38±12.60 cm, had a VO2max of 55.48±10.32 ml/kg/min and had 3.17±2.79 years of rowing experience. Physiological measures were recorded during both testing protocols. RESULTS: Maximum Power/Stroke Ratio (r = -0.96, p<0.001), Power/Stroke Ratio at the ventilatory breakpoint (r = -0.90, p<0.001), Maximal Oxygen Uptake (r = -0.84, p<0.001) and Oxygen Uptake at the ventilatory breakpoint (r = -0.82, p<0.001) were found to be strong and significant predictors of 2 kilometer rowing performance. CONCLUSION: The four significant predictors of rowing performance suggest training should focus on improving both aerobic capacity and strength. Statement of Disclosure: This study was not funded and has no conflicts of interest.

Exercise Prescription Using a Group-Normalized Rating of Perceived Exertion in Adolescents and Adults With Spina Bifida

BackgroundPeople with spina bifida (SB) face personal and environmental barriers to exercise that contribute to physical inactivity, obesity, risk of cardiovascular disease, and poor aerobic fitness. The WHEEL rating of perceived exertion (RPE) Scale was validated in people with SB to monitor exercise intensity. However, the psycho-physiological link between RPE and ventilatory breakpoint (Vpt), the group-normalized perceptual response, has not been determined and would provide a starting point for aerobic exercise in this cohort. ObjectivesThe primary objectives were to determine the group-normalized RPE equivalent to Vpt based on WHEEL and Borg Scale ratings and to develop a regression model to predict Borg Scale (conditional metric) from WHEEL Scale (criterion metric). The secondary objective was to create a table of interchangeable values between WHEEL and Borg Scale RPE for people with SB performing a load incremental stress test. DesignCross-sectional observational. SettingUniversity laboratory. ParticipantsTwenty-nine participants with SB. MethodsParticipants completed a load incremented arm ergometer exercise stress test. WHEEL and Borg Scale ratings were recorded the last 15 seconds of each 1-minute test phase. Outcome MeasuresWHEEL and Borg Scale ratings, metabolic measures (eg, oxygen consumption, carbon dioxide production). Determined Vpt via plots of oxygen consumption and carbon dioxide production against time. ResultsNineteen of 29 participants achieved Vpt (Group A). The mean ± standard deviation peak oxygen consumption at Vpt for Group A was 61.76 ± 16.26. The WHEEL and Borg Scale RPE at Vpt were 5.74 ± 2.58 (range 0-10) and 13.95 ± 3.50 (range 6-19), respectively. A significant linear regression model was developed (Borg Scale rating = 1.22 × WHEEL Scale rating + 7.14) and used to create a WHEEL-to-Borg Scale RPE conversion table. ConclusionA significant linear regression model and table of interchangeable values was developed for participants with SB. The group-normalized RPE (WHEEL, 5.74; Borg, 13.95) can be used to prescribe and self-regulate arm ergometer exercise intensity approximating the Vpt. Level of EvidenceIII

Effects of Self-Regulation at Ventilatory Breakpoint on Children’s Running Fitness during Physical Education Pedagogical Strategies

Effects of Self-Regulation at Ventilatory Breakpoint on Children’s Running Fitness during Physical Education Pedagogical Strategies

Effects of External Counterpulsation Therapy on Physiological Fitness Indicators in Healthy Adults

External counterpulsation therapy (ECP), a non-invasive treatment approved for use by the U.S. Food and Drug Administration for management of refractory angina and as therapy for heart failure patients, has shown effectiveness in relieving symptoms related to angina, acute myocardial infarction and chronic heart failure by increasing coronary blood flow and oxygen supply. Numerous studies have shown positive effects of ECP in exercise tolerance in patients with coronary heart diseases but studies on the effect of ECP in similar physiological fitness indicators of exercise in the general population are still unavailable. PURPOSE:To examine the effects of ECP on cardiovascular fitness indicators in healthy adults. METHODS:Twenty-five participants (age, 44.8 ± 8.0 years) participated in a randomised, double-blinded exploratory study and underwent 30 ECP sessions, each lasting 0.5 hours, with at least two sessions a week. A submaximal treadmill test was administered to the participants prior to the start of the first ECP treatment and following the final session of ECP. Oxygen consumption, heart rate and lactate levels were taken at every stage of the treadmill test. Related physiological fitness indicators such as the predicted maximal oxygen consumption (VO2max), ventilatory breakpoint (Vpt) and lactate threshold (LT) were calculated from the variables measured. Repeated-measures analysis of variance was used to examine the effects of ECP on each of the physiological variables. RESULTS:Time taken to Vpt has shown significant increase (p = 0.032) from pre-ECP (29.8 ± 23.8 minutes) to post-ECP (34.7 ± 20.6 minutes). Percentage of maximal oxygen consumption at Vpt also increased significantly (p = 0.014) from pre-ECP (70.9 ± 8.4%) to post-ECP (75.6 ± 7.4%). CONCLUSIONS: Results indicated that 30 sessions of ECP increased the time taken to reach Vpt and %VO2max at Vpt in healthy adults. ECP has some positive effects on cardiovascular fitness indicators as participants took a longer time to reach Vpt and were able to exercise at higher VO2max levels at Vpt. ECP may have induced central and peripheral physiological adaptations to increase the participants’ fitness levels. Supported by Renew Group Private Limited in collaboration with the Institute for Sports Research, Nanyang Technological University, Singapore.

Effects of External Counterpulsation in Healthy Adults

External counterpulsation therapy (ECP) is a non-invasive treatment to relieve symptoms related to cardiovascular diseases. Research has shown positive effects of ECP in patients with coronary heart diseases. However, the benefits of ECP in the general population remain unknown. PURPOSE: To investigate the effects of ECP on healthy middle-age adults from physio-psychological perspectives. METHODS: 25 participants underwent 30 half-an-hour ECP sessions two to three times a week. They were randomly allocated to either a high- (H: 3.0 psi) or low-pressure (L: 0.5 psi) condition. All participants performed a submaximal treadmill exercise trial before ECP (Pre), Post 15 ECP (Post- 15) and after 30 ECP (Post- 30) sessions. Predicted maximal oxygen uptake (V[Combining Dot Above]O2max), ventilatory breakpoint (Vpt), and lactate threshold (LT) were measured in each trial. During each ECP session, participants reported their perceived feelings (e.g., levels of perceived exertion as well as comfort and discomfort) using psychological scales. RESULTS: Maximal blood lactate after the submaximal exercise trial decreased from Post- 15 to Post- 30 significantly for both groups (L: 6.3 ± 1.6 to 5.2 ± 0.7; H: 5.3 ± 0.9 to 5.0 ± 0.4 mmols-1, p<0.05). V[Combining Dot Above]O2 at Vpt increased from Post- 15 to Post- 30 (L: 1.7 ± 0.4 to 1.8 ± 0.4; H;1.8 ± 0.4 to 1.9 ± 0.4 L.min -1, p<0.05). Time to Vpt increased from Pre to Post- 30 (L: 29.1 ± 31.0 to 35.6 ± 25.3; H: 30.4 ± 15.7 to 33.8 ± 16.3 minutes, p<0.05). Speed at Vpt increased from Pre to Post- 15 (L: 7.5 ± 1.8 to 7.8 ± 1.6; H: 7.4 ± 1.0 to 7.7 ± 0.9 km.hr -1, p<0.05). Systolic pressure decreased from Pre to Post- 30 (L: 123.8 ± 12.9 to 121.7 ± 11.3; H: 133.2 ± 15.9 to 126.5 ± 11.1 mmHg, p<0.05). As for psychological variables, both groups’ perceived exertion levels were below the easy level (L: 0.5 ± 0.8; H: 1.1 ± 1.3) and their perceived comfort levels remained positive (L: 6.1 ± 4.2; H: 2.8 ± 3.7) throughout the 30 ECP sessions; however, significant differences were observed in perceived comfort between the groups. CONCLUSIONS: ECP sessions had no negative effects on participants’ feelings such as perceived exertion and comfort. Cardiorespiratory fitness of both groups improved over the ECP sessions. A minimum of 30 sessions of ECP may be necessary to induce physiological changes for this population. Supported by a grant from Renew GPL, Singapore.

The Exercise Effect on the Anaerobic Threshold in Response to Graded Exercise

Introduction: Anaerobic Threshold (AT) is often expressed as a percentage of VO2 max (50% 60% for the general population, 75% and above for athletes). The higher the AT, the higher intensity the athlete can sustain without producing lactic acid. Therefore, AT is a better predictor of performance than VO2 max in elite athletes. AT is often expressed as the heart rate at the ventilatory breakpoint. The heart rate at the AT can then be utilized in designing training and interval programs for athletes. Purpose: The purpose of this study was to determine the exercise effect on anaerobic threshold from the VO2 max. Methods: Eight non-athlete subjects (age 23.25±2.55 yrs, height 177.79±9.9 cm, weight 81.36±11.13 kg) of the University of Texas at Arlington volunteered to participate in this study. Each subject had their weight, height and age for entry into a metabolic cart and on a data sheet. Each subject was outfitted with the headgear, mouthpiece and nose clip. Each subject sat at rest for five minutes to collect metabolic resting data. Next, each subject performed a graded exercise test on the treadmill with increasing speed and elevation until exhaustion. During each test heart rate (HR) and rate of perceived exertion (RPE) were recorded along with the maximal values measured by the metabolic cart, relative maximal oxygen consumption (VO2max) and minute ventilation (VE). At the end of the exercise data was collected. Results: Multiple categories were measured. The average maximal values: VO2 L/min (3.39±.9), VO2 ml/kg/min (41.41±8.58), VE L/min (94.35±25.2), RQ (1.04±.18), Q L/m (23.67±5.0), SV ml/bt (125.75±25.26), a-vO2 vol% (14.1±.99), HR (187.4±14.38), SBP (175±17.5), DBP (72.5±16.2), RPE (16.62±1.6). Conclusion: The results of this study indicated that there are some significant differences found within our population sample in terms of overall cardiovascular conditioning. It is likely there were some significant differences in the subjects’ levels of conditioning before having begun the exercise. We can predict data in the measured categories will be closer to the high end of average or nearing “elite” levels of performance in subjects with more training experience compared to subjects who entered the study with a lack of conditioning. The AT and VO2 max will be achieved more rapidly in the less conditioned subjects. 1 Department of Kinesiology, University of Texas at Arlington. 226 International Journal of Health Sciences, Vol. 3(1), March 2015

Response Normalized Omni Rating of Perceived Exertion at the Ventilatory Breakpoint in Division i Football Players

This investigation identified an OMNI Scale rating of perceived exertion associated with the ventilatory breakpoint in Division I football players. This easily applied prescriptive reference may be used to self-regulate training intensity. The OMNI Scale format may facilitate estimation of exertional perceptions. 34 participants completed a maximal treadmill test. OMNI ratings of perceived exertion were estimated during the last 15 sec. of each workload. The rating corresponding to the ventilatory breakpoint was determined for each participant using linear regression analysis. The ventilatory breakpoint corresponded to 68.8% of VO2max (SD = 7.5% of VO2 max) and a heart rate of 158.9 beats min(-1) (SD = 11.9 beats min(-1)). The rating of perceived exertion associated with the ventilatory breakpoint was 5.1 (SD = 1.2). This perceptual reference point, not previously identified in Division I football players, could be used in field settings to self-select exercise intensity around the ventilatory threshold.

The Ventilatory Response to Incremental Exercise: Is it One or Two Breakpoints?

The primary objective of this study was to determine if the ventilatory (&OV0312;E) breakpoint during incremental exercise to fatigue is best represented by a single breakpoint (BP1), double breakpoint (BP2), or an exponential function (EXP) exhibiting no BP. A secondary objective was to determine if visual assessment of the BP was valid and reliable. Subjects (n = 49) were both men (n = 12) and women (n = 37) who identified either running (n = 31) or triathlon (n = 18) as their primary sport. Subjects completed a maximal oxygen test on a motor-driven treadmill according to a modified Bruce protocol. The difference in mean square error (MSE) for BP1 (4.91 ± 3.35 L) was slightly but significantly (p < 0.05) greater than in MSE for BP2 (2.75 ± 1.7 L) for VE. Mean square error for EXP (7.85 ± 5.1 L) was significantly greater (p < 0.05) than BP1 and BP2. Visual assessment of VE on scatterplots produced poor validity, with a mean of 71.7% being misclassified compared to the computer model. Both interevaluator reliability (30.6% agreement) and intraevaluator reliability (59.7% agreement) were low. From the results of this study, it is concluded that (a) VE exhibits a BP2 model rather than BP1 or EXP and (b) visual assessment of BP is both invalid and unreliable.

Just Noticeable Difference in Perception of Physical Exertion: Relation with Ventilatory Breakpoint and Vo2peak

The just noticeable difference (JND) in the sensory response to conjunctively presented stimuli is a widely applied psychophysical measurement. However, little is known about the JND in the perception of physical exertion. PURPOSE: To describe the JND in the perception of physical exertion during submaximal cycle ergometer exercise. METHODS: Recreationally active males (n=20) and females (n=26) (age 21.4±3.1 yr) performed cycle exercise terminating at peak intensity. Rating of perceived exertion [RPE OMNI Cycle (0-10) Scale] was estimated for the overall-body at the end of each min. Individual linear regression was used to derive the power output (PO) and oxygen consumption (VO2) corresponding to an RPE of 5. This PO served as the standard. On a separate occasion four 5-min cycle exercise bouts were performed with 5 min rest between bouts. During bouts 1 and 3 subjects cycled at the standard. During bouts 2 and 4 subjects adjusted the resistance to achieve a level of exertion above or below the standard. The difference in final 30-s VO2 between each JND bout and the previous standard was taken as the physiologic analog of the above (ΔJND-A) and below (ΔJND-B) perceived exertion JND, expressed in absolute (l·min-1) and relative (%VO2PEAK) values. ΔJND-A and ΔJND-B were compared between genders, as well as between subjects exhibiting lower and higher ventilatory breakpoints (Vpt) and VO2PEAK within genders. RESULTS: For the total sample, ΔJND-B was significantly greater (p<0.05) than ΔJND-A when expressed in absolute (0.24±0.20 l·min-1 vs. 0.17±0.13 l·min-1, respectively) and relative values (8.33±6.01 %VO2PEAK vs. 5.90±4.09 %VO2PEAK, respectively). For both males and females, there were no differences in JND values between subjects with lower and higher Vpt or VO2PEAK. CONCLUSION: It is proposed that the VO2 corresponding to a JND above and below a standard stimulus can serve as an effective tool to measure a subject's perceptual acuity. This can be used to determine an individual's ability to accurately self-regulate prescribed exercise intensities. (This is a secondary analysis of a previously reported data set which has been expanded.)

Influence Of Physical Activity And Aerobic Fitness On Response Normalized Omni Ratings Of Perceived Exertion (rpe) At The Ventilatory Breakpoint (vpt)

Influence Of Physical Activity And Aerobic Fitness On Response Normalized Omni Ratings Of Perceived Exertion (rpe) At The Ventilatory Breakpoint (vpt)

Influence of Health-fitness Variables on Response Normalized Omni Rpe at the Ventilatory Breakpoint

Response normalized ratings of perceived exertion (RPE) corresponding to the ventilatory breakpoint (Vpt) during cycling have been identified in children and adults. The influence of selected health-fitness variables (HFV) on the RPE-Vpt has not been examined. This is a secondary analysis of a previously reported data set which has been expanded. PURPOSE: To determine the impact of VO2peak, Vpt expressed as a %VO2peak, BMI and body fat percentage (%BF) on the response normalized RPE-Overall (O), RPE-Legs (L), and RPE-Chest/Breathing (C) corresponding to the Vpt. METHODS: Thirty six recreationally active females (21.4 ± 3.2 yrs) completed a load-incremented cycle protocol to measure VO2peak. Subjects were dichotomized into lower and higher HFV classifications using the median for each as the cut-point. RPE-O, L, and C were measured the last 30s of each stage using the Adult OMNI Cycle Scale. RESULTS: Values are Mean ± SD: VO2peak: 2.2 ± 0.33 L·min-1; Vpt expressed as a %VO2peak: 69.9 ± 7.1; BMI: 24.1 ± 3.3 and %BF: 27.4 ± 6.7. There was a difference in RPE-O and L between lower and higher Vpt expressed as a %VO2peak (*p<0.05) (see Table). CONCLUSION: There was no difference in OMNI RPE at Vpt between lower and higher VO2peak, BMI and %BF groups. There was a difference in RPE-O and RPE-L when subjects were divided between lower and higher Vpt expressed as a %VO2peak. Therefore, OMNI RPE at the Vpt is not influenced by VO2peak, BMI or %BF in recreationally active females.Table

Influence of Body Composition on Response Normalized Omni Rpe at the Ventilatory Breakpoint

Response normalized ratings of perceived exertion (RPE) corresponding to the ventilatory breakpoint (Vpt) have been identified in children and adults using the OMNI Scale of Perceived Exertion. The influence of body composition variables including body mass index (BMI) and percent body fat (%BF) on the RPE-Vpt has not been examined in adults undergoing graded treadmill exercise PURPOSE: To determine the influence of BMI and %BF on the response normalized RPE-Overall (O), RPE-Legs (L), and RPE-Chest/Breathing (C) at the Vpt. METHODS: A randomly selected sample of 10 males (29.1 ±1.1 yrs) and ten females (29.3 ±0.8 yrs) completed a graded treadmill protocol to measure maximal oxygen uptake (VO2max). The Vpt was %VO2max at which Ve:VO2 increased without an accompanying increase in Ve:VCO2. Subjects were dichotomized into low and high body composition using the median for each variable as the cut-point. RPE-O, L, and C were measured at the last 30 seconds of each stage using the OMNI Scale. RESULTS: Mean (±SD) BMI (kg·m2) was 26.57(±5.49) for males and 27.85(±4.06) for females. Mean (± SD) %BF was 22.72(±9.25) for males and 34.93(±7.24) for females. Gender specific body composition comparisons revealed no significant differences in RPE O, L, and C at Vpt (p>0.05; Table 1).Table 1CONCLUSION: OMNI RPE-Vpt was not influenced by BMI or %BF in males or females. A normalized RPE-Vpt (1) reduces the need for pre-participation testing to prescribe exercise intensity (i.e. Vpt) that provides an overload stimulus for cardiorespiratory training; and (2) facilitates exercise intensity self-regulation. This may have a health-fitness application for adults of various levels of body composition who undertake a physical activity program. Supported by NCI (RO1CA109895)

Response Normalized Omni Rpe At The Ventilatry Breakpoint In Young Adult Males And Females

Response normalized ratings of perceived exertion (RPE) corresponding to the ventilatory breakpoint (Vpt) during cycling have been identified in children using the Children's OMNI Scale of Perceived Exertion. However, a normalized response has not been examined in adults using the OMNI-Cycle RPE Scale. PURPOSE: To identify a response normalized RPE-Overall (O), RPE-Legs (L), and RPE-Chest/Breathing (C) corresponding to the Vpt in recreationally active males and females. METHODS: Thirty-one recreationally active (< 150 min·wk-1 activity) males (n = 21, 20.7 + 2.6 yrs) and females (n = 10, 21.4 + 2.6 yrs) completed a load-incremented cycle ergometer protocol to measure VO2peak. The Adult OMNI-Cycle RPE Scale was employed to measure RPE-O, L and C during the last 30 s of each exercise minute. The Vpt was determined for each subject as the %VO2peak at which Ve:VO2 increased without an accompanying increase in Ve:VCO2. RPE-O, L and C corresponding to the Vpt were identified using individual linear regression analysis. All data are presented as means + SD. RESULTS: Mean VO2peak was 42.9 + 6.7 ml·kg-1·min-1 for males and 34.8 + 5.3 ml·kg-1·min-1 for females. Mean Vpt for males and females corresponded to 70.9 + 6.9% and 74.4 + 4.9% of VO2peak and 83.9 + 5.0% and 86.2 + 4.4% of peak heart rate, respectively. Mean response normalized RPEs corresponding to the Vpt during cycle ergometry were: RPE-O = 5.5 + 1.2, RPE-L = 6.0 + 1.1, RPE-C = 5.4 + 1.2 for males and RPE-O = 6.1 + 1.0, RPE-L = 6.2 + 1.1, RPE-C = 6.2 + 1.3 for females. There was no interaction effect of gender and rating site. However, a rating site main effect was observed when RPE data were analyzed for the combined male and female groups. Analysis of response normalized values at the Vpt indicated that RPE-L > RPE-O (p < 0.05) and RPE-L > RPE-C (p < 0.01). CONCLUSIONS: Response normalized OMNI RPEs at the Vpt were identified for undifferentiated and differentiated perceptual reports for adult males and females during cycling. These normalized responses were consistent with those reported previously for children. A normalized RPE-Vpt: (1) reduces the need for pre-participation testing to prescribe exercise intensity (i.e. Vpt) that provides an overload stimulus for cardiorespiratory training and (2) facilitates exercise intensity self-regulation by recreationally active young adults.

Relationships Among Maximal Oxygen Consumption, Ventilatory Threshold, and Elactromyographic Fatigue Threshold as Performance Assessments in College Women

PURPOSE: The purpose of this study was to examine the relationships among the power outputs (W) and VO2 values (L/min) at VO2PEAK, ventilatory threshold (VT), and electromyographic fatigue threshold (EMGFT). METHODS: Thirty-seven active women (mean ± SD: 22.03 ± 3.97 years; 166.75 ± 6.73 cm; 66.51 ± 11.14 kg) volunteered to perform two cycling tests on an electronically-braked cycle ergometer. An initial incremental exercise test was performed until exhaustion (increase of 25 W every 2 min) to determine VO2PEAK and VT. Each participant also performed a discontinuous incremental cycle ergometer test to determine their EMGFT. Four, two-minute work bouts (ranging from 75-250 W) were completed starting at each participant's power output at VT and increasing 25 W each consecutive work bout. A bipolar surface electrode arrangement, placed on the vastus lateralis of the right thigh was used to record EMG amplitude, averaged over 10 s intervals during each cycling bout. The four power outputs were plotted as a function of four EMG slope coefficients, with the y-intercept defined as the EMGFT. In addition, a regression analysis was performed to predict the VO2 value at EMGFT. Two one-way repeated measures ANOVAs were used to examine differences among power output and VO2 (L/min) measures. RESULTS: For power outputs, significant differences were observed between VO2PEAK and VT (p < 0.001; r = 0.613), VT and EMGFT (p = 0.016; r = 0.682), and VO2PEAK and EMGFT (p < 0.001; r = 0.559). For VO2, significant differences were observed between VO2PEAK and VT (p < 0.001) and VO2PEAK and EMGFT (p < 0.001). The correlations among VO2PEAK and VT, VT and EMGFT, and VO2PEAK and EMGFT were r = 0.777, 0.773, and 0.737, respectively, for VO2 values. CONCLUSION: The means at which power output and VO2 occurred for VO2PEAK, VT, and EMGFT were significantly different from each other except for the VO2 values at EMGFT and VT. This similarity, in addition to the moderate correlation of 0.773, suggested that predicted VO2 at EMGFT and VT may reflect similar physiological factors involved with the onset of fatigue during incremental exercise. Therefore, suggesting that there is a close association between the onset of peripheral fatigue measured by surface EMG and the ventilatory breakpoint that is calculated from collected gases measured with open-circuit spirometry.

Impact of metformin on peak aerobic capacity

Individually, exercise and the drug metformin have been shown to prevent or delay type 2 diabetes. Metformin mildly inhibits complex I of the electron transport system and may impact aerobic capacity in people exercising while taking metformin. The purpose of the study was to evaluate the effects of metformin on maximal aerobic capacity in healthy individuals without mitochondrial dysfunction. Seventeen healthy, normal-weight men (n=11) and women (n=6) participated in a double-blind, placebo-controlled, cross-over design. Peak aerobic capacity was measured twice using a continuous, incrementally graded protocol; once after 7-9 d of metformin (final dose=2000 mg/d) and once with placebo, with 1 week between tests. The order of the conditions was counterbalanced. Peak oxygen uptake (VO2 peak), heart rate (HR), ventilation (VE), respiratory exchange ratio (RER), rating of perceived exertion (RPE), and test duration were compared across conditions using paired t tests with the R statistical program. VO2 peak (-2.7%), peak heart rate (-2.0%), peak ventilation (-6.2%), peak RER (-3.0%), and exercise duration (-4.1%) were all reduced slightly, but significantly, with metformin (all p<0.05). There was no effect of metformin on RPE or ventilatory breakpoint. Correlations between the decrement in VO2 peak and any of the other outcome variables were weak (r2<0.20) and not significant. Short-term treatment with metformin has statistically significant, but physiologically subtle, effects that reduce key outcomes related to maximal exercise capacity. Whether this small but consistent effect is manifested in people with insulin resistance or diabetes who already have some degree of mitochondrial dysfunction remains to be determined.

Omni Scale Rating of Perceived Exertion at Ventilatory Breakpoint by Direct Observation of Children's Kinematics

Direct kinematic observation was used to measure ratings of perceived exertion at the ventilatory breakpoint (RPE-Vpt) in 10- to 14-yr.-old girls (n=22) and boys (n=22). RPE for the overall body, legs, and chest were simultaneously estimated by a trained observer and self-rated by a subject during treadmill exercise using the Children's OMNI-Walk/Run Scale. Subjects' heart rate and oxygen consumption were measured during each minute of exercise. Vpt for the girls and boys, respectively, were 64.2 and 66.5% VO2 max. RPE-Vpt ranged from 6.0 to 6.5 Overall, 7.1 to 7.6 Legs, and 5.0 to 5.5 Chest for both the observation and self-rating procedures. Responses indicated (a) RPE-Vpt (Overall, Legs, Chest) did not differ (p>.05) between the observer and self-rating procedures and (b) Observer RPE-Vpt-Legs was greater (p<.05) than RPE-Vpt-Chest. Findings validated direct kinematic observation to code group-normalized RPE-Vpt for girls and boys performing treadmill exercise.

Ventilatory Breakpoints in Boys and Men

The purpose of this study was to compare the ventilatory breakpoints during exercise between young boys and adult men. Twenty-four active volunteers, 12 boys (10.8 ± 0.3 years of age) and 12 men (24.6 ± 1.1 years of age) with similar aerobic power (53.6 ± 4.2 to 55.7 ± 3.5 mlkg−1min−1), participated in the study. Each participant completed a standardized Physical Activity Questionnaire and anthropometric variables were measured. The exercise testing consisted of two graded tests to exhaustion on a treadmill. Heart rates were recorded every minute and gas exchange parameters were obtained every 30 s throughout the tests. Each ventilatory breakpoint was determined using a three-part model. Although the relative VO2peak values were not significantly different between the boys and the young adults, the boys reported significantly (p &lt; .05) higher total activity than the adults. The boys had a significantly higher (p &gt; .05) first ventilatory breakpoint expressed as a percentage of VO2peak than the adults (64.9% vs. 57.7%). Only 50% of the boys demonstrated a discernable VB2, and the VB2 of this group was not significantly different from that of the adults.

Perceived Exertion at Ventilatory Breakpoint in Adult Females and Males Using the OMNI-Cycle RPE Scale

0822 Identification of a standardized rating of perceived exertion (RPE) zone equivalent to the ventilatory breakpoint (Vpt) can be useful for both prescription and self-regulation of aerobic exercise intensity. Such an RPE zone has been identified using the Borg (6–20) Scale. Similar evidence is not available for the OMNI Picture System to measure RPE. PURPOSE: The purpose of the study was to identify a standardized RPE zone equivalent to the ventilatory breakpoint using both the OMNI-Cycle Perceived Exertion Scale and the Borg 6–20 Scale in young adult females and males who varied in physical activity level. METHODS: The participants consisted of 13 females and 19 males, aged 25–29 years. During a graded exercise test (2 minute stages) on a cycle ergometer, RPE for the overall body was measured using both the OMNI-Cycle Scale (0–10) and the Borg Scale (6–20). Borg Scale Ratings were obtained during the first minute of each stage and OMNI Scale ratings during the second minute. Heart rate, blood pressure, ventilation and oxygen consumption were measured during the exercise test, and Vpt was calculated (%VO2peak). RESULTS: The mean VO2peak for females was 29.9 ± 8.7 ml/kg/min, and the mean VO2peak for males was 33.8 ± 6.3 ml/kg/min. The mean Vpt for females was 70.5%VO2peak, and the mean Vpt for males was 70.1%VO2peak. The mean RPE at Vpt was 6.1 ± 1.3 based on the OMNI Scale and 14 ± 1.5 based on the Borg Scale. RPE at the Vpt measured by both the OMNI and Borg Scales did not differ between genders. CONCLUSION: The results support the use of a standardized RPE zone as an indicator of the ventilatory breakpoint in young healthy female and male adults using the OMNI-Cycle Perceived Exertion Scale.

Perceived Exertion at Ventilatory Breakpoint in Adult Females and Males Using the OMNI-Cycle RPE Scale

Perceived Exertion at Ventilatory Breakpoint in Adult Females and Males Using the OMNI-Cycle RPE Scale