Graded Exercise Test Protocol Research Articles

Analysis of Cardiorespiratory Fitness in Early Adulthood and Midlife With All-Cause Mortality and Fatal or Nonfatal Cardiovascular Disease

Optimizing cardiovascular fitness is a prevention strategy against premature death and cardiovascular disease (CVD) events. Since this evidence has largely been established in older populations, the importance of cardiorespiratory fitness during earlier periods of adulthood remains unclear. To examine the association of early-adulthood cardiorespiratory fitness and percentage of early-adulthood cardiorespiratory fitness retained during midlife with subsequent risk of all-cause mortality and CVD-related morbidity and mortality overall as well as by sex and race. This retrospective population-based cohort study analyzed data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, an ongoing prospective cohort study conducted at field center clinics in Birmingham, Alabama; Chicago, Illinois; Minneapolis, Minnesota; and Oakland, California. Participants in the CARDIA study were aged 18 to 30 years when they completed the baseline graded exercise test protocol in 1985 to 1986 and have since undergone follow-up examinations biannually and every 2 to 5 years. Data were collected through August 31, 2020, and were analyzed in October 2022. Cardiorespiratory fitness was estimated from a symptom-limited, maximal graded exercise test protocol conducted at baseline and at year 7 and year 20 follow-up examinations. All-cause mortality and combined fatal and nonfatal CVD events were obtained since year 20 of follow-up examinations through August 31, 2020. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) for each primary exposure with each outcome. A total of 4808 participants (mean [SD] age at baseline, 24.8 [3.7] years; 2670 females [56%]; 2438 Black individuals [51%]) were included in the sample. During 68 751 person-years of follow-up, there were 302 deaths (6.3%) and 274 CVD events (5.7%) since year 20. Every 1-minute increment in cardiorespiratory fitness at baseline was associated with a lower risk of all-cause mortality in females (HR, 0.73; 95% CI, 0.64-0.82) and males (HR, 0.87; 95% CI, 0.80-0.96). Every 5% increment in cardiorespiratory fitness retained through year 20 was associated with a lower risk of all-cause mortality (HR, 0.89; 95% CI, 0.79-0.99), but no evidence of effect modification by race or sex was found. Every 1-minute increment in cardiorespiratory fitness at baseline was associated with a lower risk of fatal or nonfatal CVD (HR, 0.89; 95% CI, 0.82-0.96), and the estimated HR per 5% increment in cardiorespiratory fitness retained throughout midlife was 0.89 (95% CI, 0.78-1.00), with no evidence for interaction by race or sex. This cohort study found that higher early-adulthood cardiorespiratory fitness and greater retention of early-adulthood cardiorespiratory fitness throughout midlife were associated with a lower risk of premature death and CVD events. Additional research is needed to clarify the association of cardiorespiratory fitness timing across the life course with risk of clinical outcomes.

GLUCOSE INTOLERANCE PREDICTS CARDIORESPIRATORY FITNESS IN A HEALTHY POPULATION

BACKGROUND Aerobic capacity or maximum oxygen consumption rate (VO2max) is accepted as the single best indicator of cardiorespiratory fitness. VO2max is also an indicator of metabolic health and known as an all-cause mortality predictor. It is well established that glucose intolerance and insulin resistance in patients with diabetes is associated with decline in cardiorespiratory fitness. However, it is not clear if glucose intolerance is associated with poorer cardiorespiratory fitness in a population without diabetes. Therefore, the purpose of this study was to assess if glucose intolerance measured by oral glucose tolerance test (OGTT) is associated with cardiorespiratory fitness in a population without diabetes. METHODS Fifty one (30 males and 21 females) predominantly Mexican-American adults without diabetes (Age 26.1 ± 5.3 years; BMI 26.7 ± 4.2 kg/m2; fasting blood glucose 92.1 ± 10.0 mg/dL) from the border region of El Paso, TX participated in this study. VO2max was assessed using a standardized graded exercise test protocol on a treadmill with Parvomedics metabolic cart. Glucose tolerance was measured by a 3-hour OGTT preformed after a 12-hour overnight fast. Blood glucose measured at fasting and every 30 minutes after the ingestion of 75g of glucose drink during OGTT and glucose area under the curve was determined to access glucose tolerance. Pearson correlation analysis was performed at 0.05 significance level. RESULTS Glucose intolerance measured by glucose area under the curve was negatively correlated with VO2max (r = −0.40, p = 0.006). Additionally, blood glucose level during OGTT test at 120 min (r = −0.43, p = 0.003), 150 min (r = −0.36, p = 0.014), and 180 min (r = −0.32, p = 0.048) were also negatively associated with VO2max. However, fasting blood glucose was not associated with VO2max (r = −0.09, p = 0.56). CONCLUSION Poorer cardiorespiratory fitness is indicated by greater glucose intolerance and a greater surge of glucose level during an OGTT, but not fasting blood glucose in a population without diabetes.

Comparing Cardiopulmonary Functions of National Race Walkers by Walking and Running during Graded Exercise Testing

PURPOSE: This study aimed to identify a sport-specific assessment for elite race-walking athletes by comparing physiological responses between walking and running graded exercise test (GXT) protocols.METHODS: Six elite race-walking athletes completed both walking and running protocols in a randomized crossover design with 1 week interval between trials. Maximal oxygen consumption (VO<sub>2</sub>max), ventilation (VE), and heart rate (HR) were measured throughout and after each trial, and blood lactate levels were collected during the recovery period.RESULTS: There were significant differences in VO<sub>2</sub>max, VE, and HR values between the walking and running protocols (<i>p</i><.001). During the recovery period, VO<sub>2</sub>max, VE, HR, and blood lactate levels were significantly different in each measurement (<i>p</i><.001); however, there was no difference between the walking and running protocols.CONCLUSIONS: Based on these results, both the walking and running GXT protocols were inappropriate for assessing elite racewalking athletes. This study suggests that a supplement GXT protocol is required to specifically assess elite race-walking athletes.

Feasibility and suitability of a graded exercise test in patients with aggressive hemato-oncological disease

PurposePhysical activity promises to reduce disease-related symptoms and therapy-related side effects in patients suffering from aggressive lymphoma (L) or acute leukemia (AL). For an efficient training program, determination of patients’ physical capacity with a purposive exercise test is crucial. Here, we evaluated the feasibility and suitability of a graded exercise test (GXT) frequently applied in patients suffering from solid tumors by assessing whether patients achieved criteria for maximal exercise testing according to the American College of Sports Medicine (ACSM).MethodsThe GXT was performed by 51 patients with an aggressive L or AL prior to the start or in the earliest possible phase of high-dose chemotherapy, following a recommended protocol for cancer patients, starting at 20 Watts (W), with an increase of 10 W/min until volitional exhaustion. Subsequently, we investigated whether the following ACSM criteria were fulfilled: (1) failure of heart rate to increase despite increasing workload, (2) post-exercise capillary lactate concentration ≥ 8.0 mmol L−1, (3) rating of perceived exertion at exercise cessation > 17 on the 6–20 Borg Scale.ResultsOut of 51 patients, two, six, and 35 participants met the first, second, and third criterion, respectively. No relevant relationships between the completion of the criteria and patients’ characteristics (e.g., gender, age) were found.ConclusionAlthough results of this study suggest a general feasibility of the applied GXT, the ACSM criteria were not met by the majority of the participants. Therefore, this study raises doubts about the suitability of the GXT protocol and the ACSM criteria for this group of patients.

Newer Perspectives in Lactate Threshold Estimation for Endurance Sports – A Mini-Review

Lactate threshold (LT) estimation in endurance sports continues to be a widely controversial field amongst sports scientists and students despite beyond 50 years of research. With the advent of technology and superior sensors, LT research has ventured into newer fields involving wearables and artificial intelligence. Still, there is a felt need to understand the focused areas of LT research and to guide the students, sports scientists and coaches. The main aim of this mini-review is to identify research categories in a descriptive manner and to synthesize broad themes for future research from latest literature. A comprehensive electronic search in three databases was performed including only original free full text research articles conducted in athletes and heathy subjects, published in English between 2016 and 2020 following PRISMA guidelines. Out of screened 466 articles, 14 articles were finally shortlisted as per inclusion criteria and the findings were summarized. Five research categories were identified and reviewed. To conclude, there is a need for consensus in Graded Exercise test protocols used, LT concepts validity for specific sports and the application of valid, reliable noninvasive LT estimation methods in endurance sports. Synthesized broad themes would help guide sports scientists, students and researchers for future research.

Assessing Maximal Oxygen Uptake: Creating Personalized Incremental Exercise Protocols Simply and Quickly

ABSTRACT Measuring cardiorespiratory fitness (CF) is important for researchers, clinicians, and exercise practitioners to assess an individual's CF. One method of assessing CF is accomplished by measuring the maximal oxygen uptake during a personalized maximal graded exercise test (GXT). Tailoring a GXT protocol to a specific subject can be troublesome and time-consuming. In this article, simple and ready-to-use spreadsheets allowing the creation of individualized walking, running, and cycling GXT protocols are presented and explained. The procedures within the spreadsheets are based on the latest validated protocols, and the spreadsheets represent a time-saving, practical, and useful tool.

Good association between sprint power and aerobic peak power during asynchronuous arm-crank exercise in people with spinal cord injury

Purpose To (1) investigate the association between sprint power and aerobic power output (POpeakGXT) during a graded peak exercise test (GXT); and (2) validate the prediction models of POpeakGXT based on sprint power and personal and lesion characteristics. Materials and methods Wheelchair users with tetraplegia (N = 35) and paraplegia (N = 58) performed a 30 s-Wingate test and GXT on an asynchronous arm-crank ergometer. Data were split into samples to develop and validate the model. Sprint power (POmeanWingate and POpeakWingate, respectively) and POpeakGXT were determined. Regression analyses were performed to develop POpeakGXT prediction models. Candidate independent variables included POmeanWingate or POpeakWingate, age (years), sex, body mass (kg) or BMI (kg/m2), time since injury (TSI, years) and lesion level (tetraplegia/paraplegia). The best model was validated by comparing the predicted POpeakGXT with measured POpeakGXT. Results The best model (R 2 = 0.76) to predict POpeakGXT included POmeanWingate, BMI and all other independent variables. No significant difference was found between measured (68 ± 35 W) and predicted POpeakGXT (68 ± 30 W, p = 0.97). The ICC was excellent (0.89 with 95% confidence intervals: 0.75–0.95). The 95% limits of agreement for the Bland–Altman plots were wide (−30 to 31 W). Conclusions Strong associations were found between POmeanWingate and POpeakGXT. Although relative agreement was excellent, absolute agreement was low. Implications for rehabilitation There is a strong relationship between peak aerobic power output and sprint power output, both tested on an arm-crank ergometer, in people with spinal cord injury. A prediction model for peak aerobic power output, based on sprint power output and personal and lesion characteristics, showed a high explained variance. The predictive model can give a guideline for choosing the right graded exercise test protocol but should be used with caution.

Validation of an 8-minute Self-Paced Graded Exercise Testing Protocol to Elicit Maximal Responses

Recent examinations have turned to the development and validation of a 10-min self-paced graded exercise testing protocol. The 10-min duration was chosen because it represents the mean value of the recommended 8-12min ideal protocol duration; however, literature exists suggesting that an 8min duration may be more appropriate to elicit maximal exercise responses. Furthermore, a gender effect may exist to explain the finding. PURPOSE: We sought to examine maximal exercise responses during an 8-min self-paced (8SPV), 10-min self-paced (10SPV) and standardized graded exercise testing (GXT) treadmill protocols. METHODS: Sixteen recreationally active males (n=8) and females (n=8) completed three separate tests in a randomized order: a) 8SPV consisting of eight 1-min stages of increasing speed clamped by the Borg RPE6-20 scale, b) 10SPV consisting of five 2-min stages clamped of increasing speed clamped by the Borg RPE6-20 scale, c) traditional Bruce protocol as the GXT. 8SPV and 10SPV maintained a 3% grade. A two-way (gender x protocol) ANOVA with repeated measures was employed to examine differences in maximal responses between protocols. Paired samples t-tests were used to examine the difference in maximal velocity between 8SPV and 10SPV. RESULTS: No gender effects were revealed. Maximal values for 8SPV, 10SPV and GXT were similar (p > 0.05) for oxygen consumption (48.0±5.6; 51.8±10.5; 51.4±7.5 mL•kg-1•min-1), heart rate (193±11; 195±9; 194±13 beats•min-1), respiratory exchange ratio (1.11±0.07; 1.12±0.06; 1.13±0.05), ventilation (103.2±22.4; 113.0±30.3; 112.3±33.0 L•min-1), respectively. Maximal velocity for 8SPV and 10SPV were also similar (15.1±3.1 vs. 14.6±2.7 km•hr-1, p > 0.05). CONCLUSION: Given no differences between protocols, 8SPV may serve as a valid and time efficient option to elicit maximal responses during self-paced exercise in recreationally trained college-aged men and women.

Comparison of Maximal Aerobic Capacity Between the Treadmill and a Skiing Ergometer

Cross-country skiing is known to be an extremely aerobically demanding sport. Therefore, the use of a skiing ergometer (ie. SkiErg) to replicate similar aerobic training is increasing in use in lab and fitness settings. The SkiErg is widely used in gyms, research laboratories, and rehabilitation centers, and provides a low impact and total body cardiovascular and muscular endurance workout. Technique for training on the SkiErg can be quickly learned and adapted for immediate use by most individuals. Because of its lower cost and minimal required floor space, this piece of fitness equipment can be used at almost any location for exercise and training. Due to the benefits, convenience, and accessibility, the SkiErg may be a viable alternative max or peak graded exercise test (GXT) mode. To the best of the researchers’ knowledge, a comparison of aerobic capacity between a SkiErg and treadmill has not been assessed. PURPOSE: To compare treadmill (TM) VO2max values vs. those elicited from a SkiErg (SE) GXT. METHODS: Descriptive data (HT. = 176.1 + 8.2 cm, WT. = 80.5 + 10.1 kg, BF% = 15.1 + 5.8%, age = 22.7 + 2.4 yrs) was measured for 21 averagely fit college-age males. In a counterbalanced order and separated by 72 hours of rest, each subject completed 2 GXT protocols to the point of volitional exhaustion on a TM and SE. Max or peak values for VO2, HR, VE, and RER were compared between TM and SE using a Paired-Samples t-Test with an alpha level at p < 0.05. Peak RPE was compared using a Wilcoxon Signed Rank Test. RESULTS: TM was significantly greater than SE in regard to mean VO2max (51.1 ± 5.0 vs 44.5 ± 3.8 ml/kg/min, p < 0.01), HR (191 ± 11 vs 186 ± 10 bpm, p < 0.01), and RPE (19.6 + 2.2 vs 18.3 + 1.6, p = 0.039). TM was not significantly greater than SE regarding RER (1.2 + 0.0 vs 1.2 + 0.1, p = 0.862) or VE (146.2 + 16.5 vs 144.3 + 21.5 L/min, p = 0.614). CONCLUSIONS: The TM appears to yield higher max values for VO2, HR, RER, VE, and RPE values compared to SE in college-age males. Although TM elicited higher values than SE, SE VO2peak was only 15% lower than values measured from TM. This percent difference is comparable to other currently accepted alternative forms of aerobic capacity testing such as leg and arm cycle ergometers. Future studies should assess how gender, protocol variations, SE technique, or various athletic populations may impact VO2 values during a peak SE GXT.

Peak power output in handcycling of individuals with a chronic spinal cord injury: predictive modeling, validation and reference values

Purpose: To develop and validate predictive models for peak power output to provide guidelines for individualized handcycling graded exercise test protocols for people with spinal cord injury (SCI); and to define reference values.Materials and methods: Power output was measured in 128 handcyclists with SCI during a synchronous handcycling exercise test. Eighty percent of the data was used to develop four linear regression models: two theoretical and two statistical models with peak power output (in W and W/kg) as dependent variable. The other 20% of the data was used to determine agreement between predicted versus measured power output. Reference values were based on percentiles for the whole group.Results: Lesion level, handcycling training hours and sex or body mass index were significant determinants of peak power output. Theoretical models (R2 = 42%) were superior to statistical models (R2=39% for power output in W, R2 = 30% for power output in W/kg). The intraclass correlation coefficients varied between 0.35 and 0.60, depending on the model. Absolute agreement was low.Conclusions: Both models and reference values provide insight in physical capacity of people with SCI in handcycling. However, due to the large part of unexplained variance and low absolute agreement, they should be used with caution.Implications for rehabilitationIndividualization of the graded exercise test protocol is very important to attain the true peak physical capacity in individuals with spinal cord injury.The main determinants to predict peak power output during a handcycling graded exercise test for individuals with a spinal cord injury are lesion level, handcycling training hours and sex or body mass index.The predictive models for peak power output should be used with caution and should not replace a graded exercise test.

Manipulating graded exercise test variables affects the validity of the lactate threshold and [Formula: see text

BackgroundTo determine the validity of the lactate threshold (LT) and maximal oxygen uptake () determined during graded exercise test (GXT) of different durations and using different LT calculations. Trained male cyclists (n = 17) completed five GXTs of varying stage length (1, 3, 4, 7 and 10 min) to establish the LT, and a series of 30-min constant power bouts to establish the maximal lactate steady state (MLSS). was assessed during each GXT and a subsequent verification exhaustive bout (VEB), and 14 different LTs were calculated from four of the GXTs (3, 4, 7 and 10 min)—yielding a total 56 LTs. Agreement was assessed between the highest measured during each GXT () as well as between each LT and MLSS. and LT data were analysed using mean difference (MD) and intraclass correlation (ICC).ResultsThe value from GXT1 was 61.0 ± 5.3 mL.kg-1.min-1 and the peak power 420 ± 55 W (mean ± SD). The power at the MLSS was 264 ± 39 W. from GXT3, 4, 7, 10 underestimated by ~1–5 mL.kg-1.min-1. Many of the traditional LT methods were not valid and a newly developed Modified Dmax method derived from GXT4 provided the most valid estimate of the MLSS (MD = 1.1 W; ICC = 0.96).ConclusionThe data highlight how GXT protocol design and data analysis influence the determination of both and LT. It is also apparent that and LT cannot be determined in a single GXT, even with the inclusion of a VEB.

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

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

Pulse Oximetry As A Non-Invasive Method of Predicting Respiratory Compensation During Graded Exercise

Respiratory compensation (ResComp) during exercise is associated with an increase in work of breathing, decrease in economy, and initiation of the slow component of VO2 kinetics. Therefore, ResComp may be ideal for gauging an athlete’s training status. Acute metabolic acidosis at ResComp fosters weaker oxyhemoglobin association, reflected by a dip in arterial oxygen saturation (SaO2). Pulse oximetry, used to measure SaO2, may serve as an inexpensive, non-invasive method to predict ResComp. PURPOSE: The purpose of this study was to explore the validity of using SaO2 as a simple, non-invasive predictor of oxygen consumption (VO2), heart rate (HR), and respiratory exchange ratio (RER) at ResComp using different graded exercise test (GXT) protocols. METHODS: Sixteen active, healthy college students (n=16) performed a GXT to maximum on a motorized treadmill using either a three minute (n=7), one minute (n=4), or thirty second (n=5) graded protocol. Using indirect calorimetry, RespComp was determined separately by the V-slope method (V-slope), the ventilatory threshold method in which an a-linear increase in ventilatory equivalent for O2 corresponded with a decrease in peak end-tidal CO2 (PetCO2), and by detecting an a-linear decrease in SaO2 using pulse oximetry. Mixed-design repeated measures ANOVAs were used to analyze differences in the VO2, HR, and RER at ResComp across the three methods, and three GXT protocols. RESULTS: There were no significant differences in VO2 at ResComp; 3.2 l/min ± 0.9 (V-Slope), 3.2 l/min ± 0.9 (PetCO2), and 3.3 l/min ± 0.9 (SaO2); HR at ResComp; 177.1 bpm ± 6.6 (V-Slope), 177.1 bpm ± 5.3 (PetCO2), and 180.7 bpm ± 4.8 (SaO2); and RER at ResComp; 1.1 ± 0.1 (V-Slope), 1.1 ± 0.1 (PetCO2), and 1.1 ± 0.1(SaO2). There was a significant correlation in VO2 between PetCO2 and SaO2 methods used to determine ResComp (r2 = 0.93, p< 0.01). There were no significant differences among ResComp measurement methods and GXT protocols in predicting ResComp HR (p=.243); VO2 (p=.199); and RER (p=.117). CONCLUSION: Monitoring a drop in SaO2 using pulse oximetry may be a simple, non-invasive method of predicting ResComp, thereby serving as a useful tool for endurance programming and assessment.

A Comparison of Standing vs. Seated Cycle Ergometer Graded Exercise Test Protocols

A Comparison of Standing vs. Seated Cycle Ergometer Graded Exercise Test Protocols

Graded Exercise Testing Protocols for the Determination of VO2max: Historical Perspectives, Progress, and Future Considerations.

Graded exercise testing (GXT) is the most widely used assessment to examine the dynamic relationship between exercise and integrated physiological systems. The information from GXT can be applied across the spectrum of sport performance, occupational safety screening, research, and clinical diagnostics. The suitability of GXT to determine a valid maximal oxygen consumption (VO2max) has been under investigation for decades. Although a set of recommended criteria exists to verify attainment of VO2max, the methods that originally established these criteria have been scrutinized. Many studies do not apply identical criteria or fail to consider individual variability in physiological responses. As an alternative to using traditional criteria, recent research efforts have been directed toward using a supramaximal verification protocol performed after a GXT to confirm attainment of VO2max. Furthermore, the emergence of self-paced protocols has provided a simple, yet reliable approach to designing and administering GXT. In order to develop a standardized GXT protocol, additional research should further examine the utility of self-paced protocols used in conjunction with verification protocols to elicit and confirm attainment of VO2max.

Regression of Peak Oxygen Uptake and Knee Extension Torque Predicts Difference in Body Fat Values Between Skinfold and Hydrostatic Weighing Techniques

Regression of Peak Oxygen Uptake and Knee Extension Torque Predicts Difference in Body Fat Values Between Skinfold and Hydrostatic Weighing Techniques William R. Lunn, Maria Zenoni, Ian Crandall, Michelle Berglund, Ashley Dress, Robert Axtell, FACSM. Exercise Science Dept., Southern Connecticut State University, New Haven, CT Skinfold thickness determination and hydrostatic weighing are common, two-component techniques of body composition estimation. Despite test familiarization, difference in the percent body fat result between the two techniques can be observed in certain individuals, while precision is achieved in others. PURPOSE: The aim of the study was to use regression analysis to determine if the difference in body fat result (BF_diff) can be predicted by each of peak oxygen uptake (VO2peak) and peak isokinetic torque of knee extension (TORQ). METHODS: Healthy adult males (n = 51) completed two trials (one familiarization, one data collection) of each of isokinetic dynamometry of knee extension and a treadmill running VO2peak test on separate days. Isokinetic knee extension was evaluated at 180°s-1. A common graded exercise test protocol with constant treadmill speed and gradually increasing incline and indirect calorimetry was used to determine VO2peak. Standard skinfold calipers and underwater weighing with vital capacity determination were used for body fat estimation. RESULTS: Negative, moderate correlations were observed between BF_diff and each of VO2peak (r = -0.441) and TORQ (r = -0.523) (p < 0.05). A regression model was generated to predict BF_diff: y = -0.038725*TORQ - 0.87113*VO2peak (F = 10.06; p < 0.01). About 30% of the variance in BF_diff was explained by VO2peak and TORQ (R2 = 0.295). BF_diff was predicted by TORQ (p = 0.01) and VO2peak (p = 0.08). CONCLUSION: The difference in body fat values between the skinfold and hydrostatic weighing techniques can be predicted by running VO2peak or knee extension peak torque. Individuals who achieve small values for VO2peak or peak torque should be aware that only one body fat estimation technique may provide accuracy, as the BF_diff may be large.

An exercise trial targeting posterior shoulder strength in manual wheelchair users: pilot results and lessons learned

Purpose: Because wheelchair users are unable to use standard fitness equipment such as treadmills and bikes, we developed an upper body rowing ergometer (UBRE) that can be retrofitted onto a standard stationary cycle and used to perform a rowing exercise. We validated a graded exercise testing protocol utilizing the UBRE and completed a 12-week pilot intervention to compare the training effects of the UBRE to a standard arm cycle ergometer (ACE) in manual wheelchair users. Methods: Repeat graded exercise tests were compared on the two pieces of equipment. Twenty-seven manual wheelchair users participated in the intervention. Outcomes included pre- versus post-test change in shoulder pain, strength and cardiorespiratory fitness measures. Results: Testing results obtained with the UBRE were comparable to those on the ACE. In the exercise intervention, most outcome measures did not change significantly, but individuals assigned to the UBRE were able to increase their peak exercise test power by 31 W and duration by 3.6 min. Conclusion: There is biomechanical reason to believe that rowing exercises may improve shoulder muscle balance in this population, which could reduce the risk of impingement. This may be of benefit to manual wheelchair users, who are at high risk for shoulder injury.Implications for RehabilitationRegular exercise improves cardiorespiratory fitness and did not exacerbate shoulder pain in this group of manual wheelchair users.Exercises that target posterior shoulder muscle groups, such as rowing, may improve muscle balance and reduce the risk of shoulder impingement.Participation in exercise is hindered in this population by a high rate of secondary health conditions and difficulty accessing facilities and equipment.

The efficacy of the self-paced V̇O2max test to measure maximal oxygen uptake in treadmill running

The novel self-paced, cycle-based maximal oxygen uptake (V̇O2max) test (SPV) has been shown to produce higher V̇O2max values than standard graded exercise test (GXT) protocols. This study sought to ascertain whether these observations would also be apparent in a self-paced, treadmill-based test design. Fourteen trained male runners performed a standard GXT on a motorised treadmill and a self-paced V̇O2max test on a nonmotorised treadmill in a counter-balanced design. The GXT included a plateau verification and was designed to last between 8 and 12 min. The self-paced test included 5 × 2 min stages and allowed participants to set their own running speed based on fixed increments in rating of perceived exertion. Significantly higher V̇O2max values (t[13] = 3.71, p = 0.003) were achieved in the self-paced test (64.4 ± 7.3 mL · kg(-1) · min(-1)) compared with the GXT (61.3 ± 7.3 mL · kg(-1) · min(-1)), and 13 of the 14 participants achieved the same or higher V̇O2max values in the self-paced test. Higher (p = 0.01) maximum heart rates were observed in the GXT (191 ± 10 beats · min(-1) vs. 187 ± 7 beats · min(-1)), but no differences were observed in any other recorded variables. The self-paced V̇O2max test may provide a more valid means of measuring V̇O2max than the GXT and suggests that a V̇O2 plateau during a GXT does not always signify achievement of a definitive V̇O2max. These results provide further support that self-paced V̇O2max testing produces higher values for maximal oxygen uptake.

Analysis of Square-wave Bouts to Verify VO2max

Submaximal and supramaximal square-wave bouts have been reported to consistently verify 'true' VO2max. Although a direct comparison between both protocols exists, knowledge on the statistical consistency between the protocols using the same group of participants is lacking. The purpose of this study was to conduct an analysis of the submaximal and supramaximal verification bout performed shortly subsequent to a graded exercise test (GXT). On 2 separate occasions, 6 males and 7 females (age: 29±9 years) completed a GXT protocol and an exhaustive, square-wave bout at either end-GXT power minus 2-stages or 105% end-GXT power. No differences (p>0.05) in VO2max were observed between the GXT and square-wave bouts. The typical error (ml/kg/min) for submaximal (1.09) and supramaximal (1.04) trials was similar. Likewise, similar relative measures of consistency were observed for the submaximal (ICC α=0.97, CV=2.4%) and supramaximal trials (ICC α=0.95, CV=2.3%). For a GXT lasting ~10-12 min, the submaximal or supramaximal protocols appear to be equally effective.

Gas Exchange Threshold and V[Combining Dot Above]O2max Testing for Athletes

Standardized graded exercise test (GXT) protocols are ineffective for testing endurance athletes. Scientists have called for the abandonment of traditional techniques for corroborating "true" maximum oxygen uptake (VO2max), as measured during a GXT. Instead, a new technique, the verification bout subsequent to the GXT, has emerged for establishing the "true" VO2max. The addition of the verification bout reframes how the GXT should be viewed. In this article, we summarize the methods for developing custom GXT protocols, identifying threshold and interpolating power or outdoor running velocity, and implicating the verification bout.