Submaximal Test Research Articles

To jog or to stride: A comparison between two standardised running tests to monitor neuromuscular status in team sport athletes

ABSTRACT This study investigated: 1) monitoring post-match neuromuscular fatigue (NMF) status in rugby union players using two submaximal running tests (SRT); and 2) the sensitivity of each SRT to locomotor variables obtained during match-play. Twenty-three male rugby players (age: 21.0 ± 1.3 years; height: 185.2 ± 6.1 cm; body mass; 97.3 ± 10.3 kg) were monitored across one season (n = 71 player-match and 159 fatigue-players-testing observations). Two different SRTs (SRT-jog [5-minute shuttle run protocol] and SRT-stride [a repeat stride effort protocol]) were used to characterise post-match NMF, with measures taken two days prior to match day (baseline), on MD + 1, and MD + 2. Linear mixed models (±90% CIs) were used to explore differences between measures and match-play locomotor variables. SRT-jog presented a meaningful increase following MD + 1 (ES: 0.63 [0.37 to 0.89]). SRT-Stride showed small increases at MD + 1 (ES: 0.24 [0.02 to 0.49]) and MD + 2 (ES: 0.33 [0.07 to 0.59]) suggesting a potential impairment in running mechanics. SRT-stride was significantly associated with total distance (ES: 0.41 [−0.01 to 0.83]) and collisions (ES: 0.58 [0.18 to 0.99]). While both tests presented small to moderate changes post-match, only the SRT-stride was related to match locomotor variables. Therefore, the SRT-stride may be a more sensitive monitoring tool for monitoring NMF in rugby union players.

Validity and feasibility of four standardized aerobic fitness tests in patients with depression: A cross-sectional study

The objective of this study was to examine the validity and feasibility of four standardized aerobic fitness tests to either measure O2peak or to estimate O2max (e O2max) in patients with major depression disorder (MDD). To this end, all subjects (n=43) performed one maximal cardiopulmonary exercise test with gas exchange measurement (CPET) on a bicycle ergometer. Additionally, three submaximal tests (Åstrand-Rhyming bicycle ergometer test [ART], Physical work capacity test [PWC], and 6-min walk test [6MWT]) were performed within two weeks in counterbalanced order. e O2max from the submaximal tests was compared to the measured O2peak from CPET using rANOVAs, Bland-Altman plots, and correlation analyses. Feasibility outcomes (e.g., perceived exertion, discomfort, pretest anxiety, etc.) were compared via rANOVAs. On group level, e O2max estimated submaximally via ART and PWC did not differ from the CPET-based O2peak, whereas there was a bias in the 6MWT, as differences of the means increased in participants with higher O2peak. During CPET, only 56% achieved a primary or secondary criterion of maximum (physiological) exertion. On the group level, O2peak and e O2max determined with the different tests showed a sufficient degree of agreement (r≥.54, ICCs≥0.66, p<.001), but on the individual level, marked differences occurred between CPET-based O2peak and e O2max. Three of four CRF tests (CPET, ART, PWC) proved to be feasible and could be integrated into everyday therapy and monitoring of patients with MDD as an estimate for improvement of aerobic fitness. For the exact measurement of O2peak, CPET remains the gold standard, also in patients with MDD.

Exploring the physical activity levels of egyptian women with premenstrual syndrome: a preliminary study

Background and Study Aim. Premenstrual syndrome (PMS) affects a significant proportion of women, impacting their daily lives and well-being. The association between physical activity levels, the prevalence of premenstrual syndrome (PMS), and the severity of PMS remains debatable. Therefore, this study aimed to identify physical activity levels among a cohort of Egyptian females with PMS. Material and Methods. This study included one hundred females with PMS. Physical activity levels, anaerobic power, aerobic capacity, BMI, and dysmenorrhea were investigated. PMS severity was assessed using the Premenstrual Syndrome Scale (PMSS), and the females' physical activity was evaluated using the International Physical Activity Questionnaire (IPAQ). The 1-mile submaximal test and the Running-Based Anaerobic Sprint Test (RAST) were used to assess aerobic capacity and anaerobic power, respectively. Results. The findings revealed a significant association between PMS severity and physical activity (p &lt; 0.05). There was no significant difference in aerobic capacity among those with mild, moderate, and severe PMS (p &gt; 0.05). There was no significant association between PMS severity and marital status (p &gt; 0.05), whereas there was a significant association with dysmenorrhea (p &lt; 0.05), especially among moderate and severe PMS sufferers. Females with severe PMS had a significantly higher BMI than those with mild PMS (p &lt; 0.05) and those with moderate PMS (p &lt; 0.05). Mild and moderate PMS females showed no significant difference in BMI (p &gt; 0.05). Conclusions. It can be concluded that physical activity levels and BMI may affect PMS. Therefore, being physically active and maintaining a normal-range BMI might reduce PMS severity.

The added value of deep learning to submaximal exercise electrocardiogram for the 10-year prediction of major adverse cardiovascular and cerebrovascular events

Abstract Background The added value of exercise ECG data to traditional risk factors in predicting cardiovascular events remains unclear. Deep learning of ECG signals has demonstrated state-of-the-art performance in detecting subtle abnormalities indicative of cardiovascular disease. We investigated whether deep learning analysis of exercise ECGs could improve the prediction of major cardiovascular and cerebrovascular events (MACCE) with respect to established risk models in a large population-based cohort. Purpose To assess the added value of submaximal exercise ECG measurements to established cardiovascular risk prediction models. Methods We obtained ECG recordings from 41,076 UK Biobank participants without cardiovascular disease (CVD) who underwent a submaximal exercise ECG test. We obtained ECG recordings from 41,076 UK Biobank participants without cardiovascular disease (CVD) who underwent a submaximal exercise ECG test. We created two deep neural network ECG risk scores: one derived from conventional ECG parameters, measured at rest, peak exercise and late-stage recovery, and another based on the complete ECG (Q-ECG). We assessed the added value of conventional ECG parameters and Q-ECG risk scores to the UK's current prediction algorithm (QRISK3). We estimate the association between ECG parameters and MACCE, using Cox Proportional hazard models, following adjustment for traditional risk factors. All models were internally validated via 5-fold cross-validation and 1000 bootstrap iterations. Predictive performance was evaluated using Harrel's C-index, Net Reclassification Index (NRI) and net benefit. Findings: Incident MACCE was reported in 4,082 (9.9%) individuals in the study population and 3,463(9.7%) individuals with valid ECG parameters over a median follow-up period of 12.5 years. We found combined conventional ECG and Q-ECG scores were independently associated with MACCE, following adjustment for multiple testing: adjusted hazard ratio [HZ] = 1.76 (95% CI:1.63-1.91); HZ = 1.14 (95% CI:1.10-1.18), respectively, per standard deviation increase. Both conventional ECG parameters and Q-ECG were predictive of MACCE, independent of clinical risk factors, C-index = 0.64 (95%CI 0.63-0.65); net benefit = 0.09(95% CI 0.07 - 0.11) and C-index = 0.56 (95% CI 0.55-0.57); net benefit = 0.07(95% CI 0.05 - 0.09). ECG measurement's modestly improved model discrimination over the bassline QRISK3 risk score when combined with QRISK3 risk factors for conventional markers and Q-ECG score, respectively; ΔC-index 0.03 (95% CI: 0.02 – 0.04) and ΔC-index 0.03 (95% CI: 0.02 – 0.03); However, we observed no significant improvements in classification at the current recommended threshold of 10%. Conclusion In individuals without a history of prior cardiovascular disease, ECG measures independently predict the risk of MACCE. When combined with QRISK3, neural-network-derived ECG risk scores marginally improve cardiovascular risk prediction over QRISK3.

Examining the acute cardiovagal consequences of supine recovery during high-intensity interval exercise.

Exercise training requires the careful application of training dose to maximize adaptation while minimizing the risk of illness and injury. High-intensity interval training (HIIT) is a potent method for improving health and fitness but generates substantial autonomic imbalance. Assuming a supine posture between intervals is a novel strategy that could enhance physiological readiness and training adaptations. This study aimed to establish the safety and feasibility of supine recovery within a HIIT session and explore its acute effects. Fifteen healthy, active males (18-34years) underwent assessment of cardiopulmonary fitness. Participants completed two identical HIIT treadmill sessions (4 x [3min at 95% VO2max, 3min recovery]) employing passive recovery in standing (STANDard) or supine (SUPER) posture between intervals. Heart rate variability (HRV), HRV recovery (HRVrec; lnRMSSD) and heart rate recovery at 1min (HRrec) were assessed using submaximal constant speed running tests (CST) completed prior to, immediately after and 24h following HIIT. No severe adverse events occurred with SUPER, and compliance was similar between conditions (100 ± 0%). The change in HRVrec from the CST pre-to-post-HIIT was not different between conditions (p = 0.38); however, HRrec was faster following SUPER (39 ± 7bpm) vs. STANDard (36 ± 5bpm). HRV 24h post-SUPER was also greater (3.56 ± 0.57ms) compared to STANDard (3.37 ± 0.42ms). Despite no differences in perceived exertion (p = 0.23) and blood lactate levels (p = 0.35) between SUPER and STANDard, average running HRs were lower (p = 0.04) with SUPER (174 ± 7bpm) vs. STANDard (176 ± 7bpm). Supine recovery within HIIT attenuates acute cardioautonomic perturbation and accelerates post-exercise vagal reactivation. SUPER enhances recovery of vagal modulation, potentially improving physiological preparedness 24h post-HIIT. Further research exploring the chronic effects of SUPER are now warranted.

Investigating the Role of Exercise Pattern in Acute Cardiovagal Recovery.

Research on intermittent training has mainly focused on the effects of exercise intensity while overlooking the specific impact of the modulations associated with alternating exercise and recovery. This study investigated how the frequency of modulations during moderate-intensity exercise affects post-exercise vagal reactivation. Healthy, active females and males aged 18-39 years were recruited for the study. Participants completed three treadmill running sessions on separate days. Each moderate-intensity session accumulated 30 min at 90% of the intensity associated with the second ventilatory threshold and were performed as either high-frequency intermittent (HiFi; 15 x [2 min + 2 min recovery]), low-frequency intermittent (LoFi; 5 x [6 min + 2 min recovery]), or continuous training (MICT; 1 x 30 min). Heart rate recovery (HRrec) at 1 min and heart rate variability recovery (HRVrec; lnRMSSD) were assessed in response to submaximal constant-speed tests performed prior to (CST1) and following (CST2) each of the exercise sessions. HRrec, HRVrec, blood lactate (BLa), and blood pressure were also collected during the exercise sessions. Twenty-one individuals (8 females, 13 males) participated in the study. HRrec from CST2 was faster in HiFi vs. MICT (p < 0.001), while HRVrec post-CST2 was higher following HiFi vs. both LoFi (p = 0.024) and MICT (p < 0.001). BLa increased in all conditions (p = 0.007) but remained lower during HiFi compared to LoFi and MICT (both p < 0.001). Diastolic blood pressure did not change during exercise with HiFi (p = 0.939) but decreased during LoFi (p = 0.006) and MICT (p = 0.008). Exercise pattern influences the physiologic response to exercise. Higher frequencies of modulations can preserve vagal activity and expedite post-exercise recovery, suggesting moderate-intensity intermittent exercise as a potential strategy to mitigate autonomic impact and acute physiological stress while maintaining total work performed.

Electroacupuncture Reduces Heart Rate and Perceived Exertion During a Bike Test: A Preliminary Analysis.

Preliminary research suggests that acupuncture can improve cardiovascular function. The purpose of our study was to determine if electroacupuncture can improve performance and post-exercise recovery. Thirty-two healthy people participated in this study (14 men and 18 women, aged 23.6 ± 3.5 years). The first visit included baseline measurements. Then, the participants received daily electroacupuncture at acupuncture point PC6 for a week, followed by a second visit. Heart rate, perceived exertion, and systolic and diastolic blood pressure were measured before, during, and after a YMCA submaximal bike test. The heart rate was significantly reduced during the final stage of the YMCA test (151.3 ± 7.0 to 146.7 ± 11.8; p = 0.013) on the second visit. The rate of perceived exertion was significantly lower during all stages in Visit 2 (average RPE Visit 2 = 10.71 ± 2.02; average RPE Visit 1 = 11.45 ± 1.98; p = 0.004). Systolic blood pressure significantly decreased during the 5 min post-test recovery (SBP Visit 2 = 116.9 ± 12.0; SBP Visit 1 = 145.7 ± 14.6, p < 0.05). A week of electroacupuncture at PC6 led to reduced heart rate and perceived exertion during exercise, making the workload feel less strenuous. Electroacupuncture at PC6 shows potential for increasing participation in physical activities by making them feel easier to accomplish.

Durability in recreational runners: effects of 90-min low-intensity exercise on the running speed at the lactate threshold.

Recent studies have suggested that the capability to resist deterioration of physiological characteristics could be an independent factor contributing to endurance performance. This study aimed at investigating whether prolonged low-intensity exercise induces shifts in the lactate threshold, and whether fatigue-induced changes differ between the sexes. A total of 31 (15 females) recreational runners performed an incremental treadmill test and a 90-min low-intensity exercise (LIT90) on two separate occasions. The LIT90 was performed at 90% of the first lactate threshold speed (LT1v), derived from the incremental treadmill test. The LT1v was determined from a 5-stage (3min) submaximal threshold test (SubmaxLT), performed before and after LIT90. The SubmaxLTs were followed by a 10/5 reactivity jump test. Respiratory gases, heart rate (HR), and HR-derived detrended fluctuation analysis alpha 1 (DFA-a1) were assessed every 15min during the LIT90. A significant decrease (p < 0.01) was observed in the LT1v in females (-5.8 ± 4.4%) and in males (-5.3 ± 6.4%). The HR increased (p < 0.001) similarly in females (5.9 ± 3.1%) and in males (5.5 ± 3.6%) during the LIT90, while energy expenditure increased (3.1 ± 4.5%, p = 0.013) in females but remained unchanged in males (0.9 ± 3.1%). Change in DFA-a1 during the LIT90 was the only marker that correlated significantly with the relative change of LT1v (r = 0.463, p = 0.013). LIT90 induced significant decreases in the LT1v, and the changes were comparable between sexes. DFA-a1 could be a potential intra-session marker of durability.

Accuracy of smartwatches for the remote assessment of exercise capacity

Exercise capacity is a strong independent predictor of cardiovascular and all-cause mortality. The utilization of well-established submaximal tests of exercise capacity such as the 6-min walk test (6MWT), 3-min step test (3MST) and 10-chair rise test (10CRT) in the community would improve patient care but requires remote monitoring technology. Consumer grade smartwatches provide such an opportunity, however, their accuracy in measuring physiological responses to these tests is unclear. The aim of this study was to determine the accuracy of consumer grade smartwatches in assessing exercise capacity to develop a framework for remote, unsupervised testing. 16 healthy adults (7 male (44%), age median 27 [interquartile range (IQR) 26,29] years) performed 6MWTs using two protocols: (1) standard—straight 30 m laps (6MWT-standard) and 2) continuous lap—circular 240 m laps around a park (6MWT-continuous lap), 3MSTs and 10CRTs. Each one of these four tests was performed three times across two clinic visits. Each participant was fitted with a Garmin Vivoactive4 and Fitbit Sense smartwatch to measure three parameters: distance, step counts and heart rate (HR) response. Reference measures were a meter-wheel, hand tally counter and ECG, respectively. Mean HR was measured at rest, peak exercise and recovery. Agreement was measured using Bland–Altman analysis for repeated measures and summarized as median absolute percentage errors (MAPE). Distance during 6MWT-continuous lap had better agreement than during 6MWT-standard for both Garmin (MAPE: 6.4% [3.0, 10.4%] versus 20.1% [13.9, 28.4%], p < 0.001) and Fitbit (8.0% [2.9, 10.1% versus 18.8% [15.2, 28.1%], p < 0.001). Garmin measured step count more accurately than Fitbit (MAPE: 1.8% [0.9, 2.9%] versus 8.0% [2.6, 12.3%], p < 0.001). Irrespective of test, both devices showed excellent accuracy in measuring HR at rest and recovery (≤ 3%), while accuracy decreased during peak exercise (Fitbit: ~ 12% and Garmin: ~ 7%). In young adults without mobility difficulties, exercise capacity can be measured remotely using standardized tests and consumer grade smartwatches.

Impact of different training protocols on muscle synergism in maximal and submaximal strength tests in bench press exercise

Impact of different training protocols on muscle synergism in maximal and submaximal strength tests in bench press exercise

Ratings of perceived exertion (RPE) from a submaximal 20-m shuttle-run test accurately predict children's VO2peak, but when should we stop the test?

The purpose of the study was to explore the validity, test-retest reliability and affective responses of a submaximal 20-m shuttle-run test (20mSRT) stopped at 6 on the Eston-Parfitt (EP) scale. The secondary aim was to examine and compare two submaximal 20mSRT protocols with different RPE end points (EP6 vs. EP7) using previously published data. Twenty-five children (16 boys; 13.4 ± 1.0years; 162.1 ± 8.7cm; 49.1 ± 6.6kg) completed three exercise tests (graded exercise test [GXT], 2 submaximal 20mSRT). The EP scale and Feeling scale were used to measure RPE and affect, respectively. The two submaximal 20mSRTs were stopped after participants reported EP6. Individual speed-RPE relationships from the submaximal 20mSRTs were linearly regressed to predict peak speed and then used to estimate VO2peak. Previously published data (n = 25) used comparable methods, except that the participants stopped at EP7. In the EP6 protocol, a two-factor repeated measures ANOVA revealed non-significant Test and Sex main effects (p > 0.05). Reliability analysis revealed intraclass correlation coefficient of ~ 0.7 (95%CI [0.432,0.867], p < 0.001) between the submaximal 20mSRTs. Significant differences in end-test affect between the GXT and submaximal 20mSRTs were found (p < 0.001), with GXT more negative. ANOVA revealed no significant differences in end-test affect between EP6 and EP7 protocols; however, frequency count analysis revealed EP6 to result in more positive end-test affect. Submaximal 20mSRT utilising RPE may offer valid predictions in VO2peak while minimising negative affect. Test end points of EP6 and EP7 both offer valid predictions in VO2peak. EP6 may be more beneficial in avoiding negative affect, even though a reduction in test-retest reliability was observed.

Submaximal Verification Test to Exhaustion Confirms Maximal Oxygen Uptake: Roles of Anaerobic Performance and Respiratory Muscle Strength.

Background: The incremental exercise test is commonly used to measure maximal oxygen uptake (VO2max), but an additional verification test is often recommended as the "gold standard" to confirm the true VO2max. Therefore, the aim of this study was to compare the peak oxygen uptake (VO2peak) obtained in the ramp incremental exercise test and that in the verification test performed on different days at submaximal intensity. Additionally, we examined the roles of anaerobic performance and respiratory muscle strength. Methods: Sixteen physically active men participated in the study, with an average age of 22.7 ± 2.4 (years), height of 178.0 ± 7.4 (cm), and weight of 77.4 ± 7.3 (kg). They performed the three following tests on a cycle ergometer: the Wingate Anaerobic Test (WAnT), the ramp incremental exercise test (IETRAMP), and the verification test performed at an intensity of 85% (VER85) maximal power, which was obtained during the IETRAMP. Results: No significant difference was observed in the peak oxygen uptake between the IETRAMP and VER85 (p = 0.51). The coefficient of variation was 3.1% and the Bland-Altman analysis showed a high agreement. We found significant correlations between the total work performed in the IETRAMP, the anaerobic peak power (r = 0.52, p ≤ 0.05), and the total work obtained in the WAnT (r = 0.67, p ≤ 0.01). There were no significant differences in post-exercise changes in the strength of the inspiratory and expiratory muscles after the IETRAMP and the VER85. Conclusions: The submaximal intensity verification test performed on different days provided reliable values that confirmed the real VO2max, which was not limited by respiratory muscle fatigue. This verification test may be suggested for participants with a lower anaerobic mechanical performance.

Graded Intensity Aerobic Exercise to Improve Cerebrovascular Function and Performance in Older Veterans: Protocol for a Randomized Controlled Trial.

Growing health care challenges resulting from a rapidly expanding aging population necessitate examining effective rehabilitation techniques that mitigate age-related comorbidity and improve quality of life. To date, exercise is one of a few proven interventions known to attenuate age-related declines in cognitive and sensorimotor functions critical to sustained independence. This work aims to implement a multimodal imaging approach to better understand the mechanistic underpinnings of the beneficial exercise-induced adaptations to sedentary older adults' brains and behaviors. Due to the complex cerebral and vascular dynamics that encompass neuroplastic change with aging and exercise, we propose an imaging protocol that will model exercise-induced changes to cerebral perfusion, cerebral vascular reactivity (CVR), and cognitive and sensorimotor task-dependent functional magnetic resonance imaging (fMRI) after prescribed exercise. Sedentary older adults (aged 65-80 years) were randomly assigned to either a 12-week aerobic-based interval-based cycling intervention or a 12-week balance and stretching intervention. Assessments of cardiovascular fitness used the YMCA submaximal VO2 test, basal cerebral perfusion using arterial spin labeling (ASL), CVR using hypercapnic fMRI, and cortical activation using fMRI during verbal fluency and motor tapping tasks. A battery of cognitive-executive and motor function tasks outside the scanning environment will be performed before and after the interventions. Our studies and others show that improved cardiovascular fitness in older adults results in improved outcomes related to physical and cognitive health as well as quality of life. A consistent but unexplained finding in many of these studies is a change in cortical activation patterns during task-based fMRI, which corresponds with improved task performance (cognitive-executive and motor). We hypothesize that the 12-week aerobic exercise intervention will increase basal perfusion and improve CVR through a greater magnitude of reactivity in brain areas susceptible to neural and vascular decline (inferior frontal and motor cortices) in previously sedentary older adults. To differentiate between neural and vascular adaptations in these regions, we will map changes in basal perfusion and CVR over the inferior frontal and the motor cortices-regions we have previously shown to be beneficially altered during fMRI BOLD (blood oxygen level dependent), such as verbal fluency and motor tapping, through improved cardiovascular fitness. Exercise is one of the most impactful interventions for improving physical and cognitive health in aging. This study aims to better understand the mechanistic underpinnings of improved health and function of the cerebrovascular system. If our hypothesis of improved perfusion and cerebrovascular reactivity following a 12-week aerobic exercise intervention is supported, it would add critically important insights into the potential of exercise to improve brain health in aging and could inform exercise prescription for older adults at risk for neurodegenerative disease brought on by cerebrovascular dysfunction. ClinicalTrials.gov NCT05932069; https://clinicaltrials.gov/study/NCT05932069. DERR1-10.2196/58316.

Evaluation of fatigue and fatigability in people with Duchenne muscular dystrophy using a dynamic arm support – a pilot study

Background Due to progressive muscle wasting and weakness in patients with Duchenne Muscular Dystrophy (DMD), physical fatigability increases, upper extremity function reduces, which negatively impacts quality of life. Assistive technology such as dynamic arm supports (DAS) may help reduce this fatigability. This study aims to assess whether the novel Yumen ‘EXone’ DAS can reduce upper extremity fatigue and fatigability in DMD patients and healthy controls (HC), both with and without the DAS. Additionally, longitudinal changes in DMD patients were evaluated. Methods Five DMD patients from the Yumen Bionics pioneer program and five HCs participated. Two submaximal tests simulating drinking and reaching were performed for two minutes, each with and without DAS. DMD participants completed these tests twice, at baseline (T0) and after 6-9 months (T1), while HCs completed them once. Physical fatigability was measured by the number of repetitions and changes in surface electromyography (sEMG) amplitude. Subjective fatigue was assessed using the Borg Scale (6-20) Rate of Perceived Exertion (RPE). Results DMD participants generally performed more repetitions with the DAS than without. HCs showed similar or increased repetitions with the DAS. Assessing fatigability with sEMG was difficult due to the compensatory mechanisms used for the tests. Subjective fatigue scores on the Borg Scale were lower with the DAS for both DMD patients and HCs. Conclusion The Yumen ‘EXone’ DAS effectively reduces both fatigue and fatigability in DMD patients and healthy controls. Despite the methodological shortcomings, this research is one of the first studies investigating the impact of DAS on fatigue and fatigability.

Fractional utilization of the 10-minute treadmill test velocity in running performance.

This study aimed to evaluate the applicability of the 10-minute submaximal treadmill test (T10 test), a self-paced test, in determining critical speed (CS) and predicting running performance. Specifically, we sought to identify the percentage of T10 velocity (vT10) that runners performed in official distance races, and to compare physiological and performance indicators between sexes. 60 recreational runners (n = 34 males and n = 26 females) underwent a maximum incremental test, the novel T10 test, and ran 1200-m and 2400-m on the track. Runners self-reported their best performance times. Generalized Linear Model was used to compare running performances between sexes. For both males and females, the %vT10 in 5km, 10km, and half-marathon races occurred at 107.5% and 106.5%, 99.9% and 100.8%, and 92.6% and 97.1%, respectively. There was no interaction effect (p = .520) and no main effect of sex (p = .443). There was a main effect of distance (p < .001), indicating that %vT10 in the 5km race differed from that found in the 10km race (p = .012), as well as in the half-marathon (p < .001). Our findings suggest that %vT10 values can be used to determine pace in recreational endurance runners for race distances regardless of sex.

Cardiorespiratory Fitness Assessment for Exercise Research in Mild Cognitive Impairment Due to Alzheimer's Disease.

To analyze cardiorespiratory fitness (CRF) levels using the gold-standard, laboratory-based cardiopulmonary exercise test (CPET) in community-dwelling older adults (N = 145) with amnestic mild cognitive impairment (aMCI), specifically CPET feasibility, CRF prediction, and CRF status in comparison to published sedentary, cognitively normal, age- and sex-adjusted normative data. Peak oxygen consumption (VO2Peak [mL/kg/min]) was assessed by CPET, which was categorized as submaximal, near-maximal, or maximal tests. VO2Max predicted was compared to VO2Max measured to assess its utility. Data were analyzed with t tests. Participants' mean age was 73.77 years (SD = 5.74 years), with 51.7% males, 91.7% Caucasian, 68.3% married, and 16.9 years (SD = 2.88 years) of education. Mean VO2Peak measured was 17.07 (SD = 4.92) for the total sample (18.29 [SD = 4.64] for males, 15.78 [SD = 4.91] for females). Sixteen (11.03%) CPETs were submaximal, 53 (36.55%) were near-maximal, and 76 (52.41%) were maximal. Mean VO2Max predicted was 28.59 (SD = 21.94) for the total sample (29.36 [SD = 22.3] for males, 27.76 [SD = 21.68] for females) and was significantly higher than VO2Max measured (p < 0.0001). Among participants with maximal CPETs, VO2Peak measured was significantly lower than sedentary normative data (p < 0.0001). CPET was feasible for older adults with aMCI. VO2Max predicted overly inflates CRF estimates. Low levels of CRF in older adults with aMCI suggest aerobic exercise as an important intervention. [Journal of Gerontological Nursing, 50(9), 31-36.].

Comparison of community ambulation intensity determined from overground and treadmill walking cadence cut points: Is there a relationship between step activity measures and predicted VO2 max in healthy children and adults?

BackgroundThis study was designed to evaluate the effect of using maximal cadence criteria cut points established during overground and treadmill walking, on intensity outputs measured during community ambulation. The second aim was to establish the relationship between cardiovascular fitness (predicted VO2 max capacity) and community ambulation intensity performance, in typically developing individuals. Research QuestionWhat is the effect on intensity measures when using cadence cut point criteria derived from overground and treadmill walking and does predicted VO2 max correlate with exercise related community activity in a typically developing population? MethodsA group of 37 typically developing participants between 8 and 27 years of age, underwent a graded submaximal VO2 testing protocol followed by a typical week of community ambulation, recorded with a step activity monitor. Maximum cadence criteria established during overground and treadmill walking were applied and the data were compared. The weekly step activity variables included: total steps, total ambulatory time, intensity, duration, and volume. Predicted VO2 Max was calculated, and correlations calculated to step activity outputs. ResultsResults showed significant differences (p<0.001) between cadence cut point criteria across all intensity measures except in the amount of time spent in the 30–60 % intensity category (p=0.182). Predicted VO2 max did not significantly correlate with step activity outputs related to exercise (moderate+ intensity and long duration ambulatory bouts; p>0.277). SignificanceThis study illustrates the importance of close consideration in applying recommended cut off criteria when assessing intensity outputs from step activity data. Cadence from both overground and treadmill walking were collected in a controlled lab setting, but the influence of the treadmill mechanical and forced cadence criteria must be considered when selecting intensity cut points.

Salivary cortisol measurements in brachycephalic dog breeds as part of a standardized stress test.

Brachycephalic obstructive airway syndrome (BOAS) is a common condition in brachycephalic dogs, with Pugs (PG) and French Bulldogs (FB) appearing to be particularly typically affected. Objective and easy-to-perform tests are necessary to detect the disease at an early stage and to exclude dogs affected by BOAS from breeding. The present study investigated the extent to which vital signs and salivary cortisol concentrations can be used to distinguish between healthy and BOAS-affected dogs in a standardized fitness test. A total of 57 PG, 56 FB and 27 meso- and dolichocephalic dogs were studied as control group (CG). In addition to vital signs, salivary cortisol concentrations were measured before and after the exercise test. It emerged that non-brachycephalic dogs showed a higher fitness level than brachycephalic dogs. The PG recovered significantly slower than the FB after the exercise test. In unaffected PG, cortisol levels rose significantly after the test and then fell again, in unaffected FB they fell significantly during the test. Unexpectedly, cortisol levels remained constant in BOAS affected dogs of both breeds. A possible explanation could be a disturbance of the pituitary-hypothalamic-adrenal axis, which could be due to the chronic stress of affected animals. This would have to be clarified in further studies. In conclusion, a submaximal fitness test may be a useful method to identify dogs suffering from BOAS as it is imperative to prevent the breeding and reproduction of affected dogs.

Metabolic flexibility and resting autonomic function in active menopausal women.

The present study aims to analyze the relationship between cardiac autonomic control at rest-i.e., baseline Heart Rate Variability (HRV)-and metabolic flexibility assessed by means of the FATox and CHOox oxidation rates at the intensities of maximum fat and carbohydrate oxidation (MFO and MCO, respectively). Twenty-four active over-60 women (66.8 ± 4.4years) had their HRV assessed with 10min recordings under resting conditions, and this was analyzed with Kubios Scientific software. After this, an incremental submaximal cycling test, starting at 30watts, with increments of 10watts every 3min 15s was performed. FATox and CHOox were calculated in the last 60s at each step, using Frayn's equation. MFO and MCO were further obtained. Nonlinear SampEn and 1-DFAα1 (Detrending Fluctuation Analysis score) at rest were both moderate and significantly (p < 0.05) related to FATox (r = 0.43, r = -0.40) and CHOox (r = -0.59, r = 0.41), as well as RER (r = -0.43, r = 0.43) at FATmax intensity. At the MCO intensity, no association was observed between HRV and oxidation rates. However, DFAα1 (r = -0.63, p < 0.05), the frequency ratio LF/HF (r = -0.63, p < 0.05), and the Poincaré ratio SD1/SD2 (r = 0.48, p < 0.05) were correlated with blood lactate concentration. These results support the autonomic resources hypothesis, suggesting that better autonomic function at rest is related to enhanced metabolic flexibility in postmenopausal women. They also underpin a comprehensive analysis of cardiovascular-autonomic health with aging. The results imply that non-linear DFAα1 and SampEn are appropriate to analyze this association in health of the aging cardiovascular-autonomic system.

Impact of probiotic supplementation on exercise endurance among nonelite athletes: a randomized, placebo-controlled, double-blind, clinical trial.

This randomized, placebo-controlled, double-blind, parallel trial investigated whether generally healthy adult, nonelite runners would have a greater time-to-exhaustion during submaximal treadmill running with probiotic versus placebo supplementation. It was hypothesized that the probiotic would impact training progression by reducing gastrointestinal (GI) and cold/flu symptoms. Participants who typically ran ≥24km/week, ran or cross-trained 3-5 days per week, and had a maximal oxygen intake (V̇O2 max) in the 60-85th percentile were enrolled. V̇O2 max was used to establish individualized workload settings (85% of V̇O2 max) for the submaximal endurance tests at baseline and following 6 weeks of supplementation with a probiotic (Lactobacillus helveticus Lafti L10, 5×109 CFU/capsule/day) or placebo. Participants self-reported GI and cold/flu symptoms and physical activity via daily and weekly questionnaires. Outcomes were tested using a linear model to determine if mean response values adjusted for baseline differed between groups. Twenty-eight participants (n=14/group), aged 25±5 years (mean±SD) with a body mass index of 23 ± 3kg/m2, completed the study. At the final visit the probiotic group had a lower time-to-exhaustion versus the placebo group (P=0.01) due to an increase in time-to-exhaustion with the placebo (1344±188 to 1565±219 s, P=0.01) with no change with the probiotic (1655±230 to 1547±215 s, P=0.23). During the intervention, the probiotic group completed fewer aerobic training sessions per week (P=0.02) and trained at a lower intensity (P=0.007) versus the placebo group. Few GI and cold/flu symptoms were reported with no differences between groups. Time-to-exhaustion increased in the placebo group, possibly due to differences in training habits.