Reliability and Validity of a Flume-Based Maximal Oxygen Uptake Swimming Test.

A mode-specific swimming protocol to assess maximal aerobic uptake (VO2maxsw) is vital to accurately evaluate swimming performance. A need exists for reliable and valid swimming protocols that assess VO2maxsw in a flume environment. The purpose was to assess: (a) reliability and (b) "performance" validity of a VO2maxsw flume protocol using the 457-m freestyle pool performance swim (PS) test as the criterion. Nineteen males (n = 9) and females (n = 10) (age, 28.5 ± 8.3 years.; height, 174.7 ± 8.2 cm; mass, 72.9 ± 12.5 kg; %body fat, 21.4 ± 5.9) performed two flume VO2maxsw tests (VO2maxswA and VO2maxswB) and one PS test [457 m (469.4 ± 94.7 s)]. For test-retest reliability (Trials A vs. B), moderately strong relationships were established for VO2maxsw (mL·kg-1·min-1)(r= 0.628, p = 0.002), O2pulse (mL O2·beat-1)(r = 0.502, p = 0.014), VEmax (L·min-1) (r = 0.671, p = 0.001), final test time (sec) (0.608, p = 0.004), and immediate post-test blood lactate (IPE (BLa)) (0.716, p = 0.001). For performance validity, moderately strong relationships (p < 0.05) were found between VO2maxswA (r =-0.648, p = 0.005), O2pulse (r= -0.623, p = 0.008), VEmax (r = -0.509 p = 0.037), and 457-m swim times. The swimming flume protocol examined is a reliable and valid assessment of VO2maxsw., and offers an alternative for military, open water, or those seeking complementary forms of training to improve swimming performance.

Isotemporal Associations of Device-Measured Sedentary Time and Physical Activity with Cardiac-Autonomic Regulation in Previously Pregnant Women.

BACKGROUND: High sedentary time (ST) and low physical activity may increase cardiovascular risk, potentially though cardiac-autonomic dysregulation. This study investigated associations of statistically exchanging device-measured ST and physical activity with measures of cardiac-autonomic regulation in previously pregnant women. METHOD: This cross-sectional, secondary analysis included 286 women (age = 32.6 ± 5.7 years; 68% white) measured 7-15 years after delivery. ST and light (LPA), moderate (MPA), vigorous (VPA), and moderate-to-vigorous (MVPA) intensity physical activity were measured by ActiGraph GT3X. ST was further partitioned into long (≥ 30 min) and short (< 30 min) bouts. MVPA was also partitioned into long (≥ 10 min) and short (< 10 min) bouts. Cardiac-autonomic regulation was assessed by heart rate variability (HRV) (resting heart rate, natural log transformed standard deviation of normal R-R intervals [lnSDNN], natural log-transformed root mean square of successive differences [lnRMSSD]) from a 5-min seated ECG. Progressive isotemporal substitution models adjusted for confounders. Sensitivity analyses removed women with related underlying medical conditions and who did not meet respiration rate criteria. RESULTS: Initial analyses found no significant associations with HRV when exchanging 30 min of ST and physical activity (p > 0.05). Yet, replacing long- and short-bout ST with 30 min of long-bout MVPA yielded significantly higher (healthier) lnRMSSD (B = 0.063 ± 0.030 and B = 0.056 ± 0.027, respectively; both p < 0.05). Sensitivity analyses strengthened these associations and yielded further associations of higher lnSDNN and lnRMSSD when replacing 30 min of short-bout MVPA with equivalent amounts of long-bout MVPA (B = 0.074 ± 0.037 and B = 0.091 ± 0.046, respectively). CONCLUSION: Replacing ST with long-bout MVPA is a potential strategy to improve cardiac-autonomic function in previously pregnant women.

Gender Differences and the Influence of Body Composition on Land and Pool-Based Assessments of Anaerobic Power and Capacity.

Consistent differences between males and females have been shown in land-based measurements of anaerobic power and capacity. However, these differences have not been investigated for a tethered 30-s maximal swimming test (TST). The purpose of this study is to explore gender differences in land and pool-based assessments of anaerobic power (Fpeak) and capacity (Fmean), as well as the influence of body composition. Thirteen males and fifteen females completed land (Wingate (WAnT)) and pool-based (TST) measures of anaerobic power and capacity previously described in the literature. Additionally, the subjects completed assessments of body composition via air displacement plethysmography. The males produced higher force than the females for Fpeak (p < 0.001) and Fmean (p = 0.008) during the TST. However, linear regression analysis determined that lean mass significantly predicted Fpeak (p = 0.002) and Fmean (p < 0.001) during the TST, while gender was no longer significant (p = 0.694 and p = 0.136, respectively). In conclusion, increases in anaerobic power and capacity (Fpeak and Fmean) may be a function of increased lean mass in males and females, warranting future research on the impact of resistance training programs on force production and swimming performance.

Cardiovascular responses to physical activity during work and leisure.

OBJECTIVES: Recent evidence suggests that occupational physical activity (OPA) is associated with adverse cardiovascular health, whereas leisure time physical activity is protective. This study explored explanatory physiological mechanisms. METHODS: Nineteen males (68% white, age=46.6±7.9 years, body mass index=27.9±5.1 kg/m2) with high self-reported OPA wore activity (ActiGraph and activPAL) and heart rate (HR) monitors for 7 days and an ambulatory blood pressure (BP) monitor on one workday and one non-workday. Mixed effects models compared cardiovascular variables (24-hour, nocturnal, waking and non-work time HR and BP) and nocturnal HR variability (HRV) on workdays versus non-workdays. Additional models examined associations of daily activity (steps, light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA)) with cardiovascular variables. Workday by daily activity interactions were examined. RESULTS: 24-hour and waking HR and diastolic BP as well as non-work diastolic BP were significantly higher on workdays versus non-workdays (p<0.05 for all). However, no difference in systolic BP or nocturnal HR or BP was observed between work and non-workdays (p>0.05 for all). Low-frequency and high-frequency power indices of nocturnal HRV were lower on workdays (p<0.05 for both). Daily steps and LPA were positively associated with 24-hour and waking HR on work and non-workdays. Significant interactions suggested MVPA increases HR and lowers nocturnal HRV during workdays, with the opposite effect on non-workdays. CONCLUSIONS: Cardiovascular load was higher on workdays versus non-workdays with no compensatory hypotensive response following workdays. Daily MVPA may differentially affect ambulatory cardiovascular load and nocturnal HRV on workdays versus non-workdays, supporting the physical activity health paradox hypothesis.

Association of Physical Activity and Sedentary Time with Cardio-Autonomic Regulation in Women.

Background: Low moderate-to-vigorous-intensity physical activity (MVPA) and high sedentary time (ST) may contribute to cardiovascular disease (CVD) risk in women, perhaps via cardiac autonomic dysregulation. We examined associations of total, leisure, and occupational MVPA and ST with cardiac autonomic regulation in women. Methods: Data were from 522 women (age = 37.7 ± 5.7 years; 59%white) who participated in the follow-up study of the Pregnancy Outcomes and Community Health Study (between 2011 and 2014). MVPA and ST (hours/day) were self-reported using the Modifiable Activity Questionnaire. Cardiac autonomic regulation was assessed by calculating heart rate variability (HRV) indices (resting heart rate, natural logarithm standard deviation of normal R-R intervals; lnSDNN [total variability], natural logarithm root mean square of the successive differences; lnRMSSD [cardiac parasympathetic activity]) with Kubios software from a 5-minute, seated electrocardiogram. Progressive generalized linear models evaluated associations of total, leisure, and occupational MVPA and ST with HRV indices while adjusting for confounders (demographics, health-related factors), and then potential mediators (clinical variables). A final model evaluated the relationship between ST and HRV stratified by MVPA level. Results: Adjusting for confounders, total and leisure MVPA were associated with favorable lnSDNN (B = 0.027 [p = 0.014] and B = 0.074 [p = 0.009], respectively) and lnRMSSD (B = 0.036 [p = 0.015] and B = 0.075 [p = 0.043], respectively). Adjustment for mediators tended to strengthen the observed significant associations. No associations were found between occupational MVPA or any ST measure with HRV indices (p > 0.05). Neither MVPA nor ST were associated with heart rate. When stratified by MVPA level, leisure ST was associated with unfavorable lnRMSSD (B = -0.041, [p = 0.042]) only among women who did not meet leisure MVPA recommendations. Conclusion: Cardiac autonomic dysregulation may be a mechanism through which low leisure MVPA and, among low-active women, high leisure ST contribute to CVD risk among women.

Physical Activity in the Workplace: Does Just Working Meet Activity Recommendations?

Background: The physical activity (PA) health paradox hypothesizes that occupational physical activity (OPA) and leisure time PA have differential cardiovascular health effects due to increased cardiovascular load without adequate recovery; however, research describing worker PA lacks high-quality objective OPA measurement. This study aimed to objectively describe PA profiles of men reporting high OPA and make comparisons to aerobic PA and OPA recommendations. Methods: Male food service, material moving, health care, or maintenance workers wore activity (ActiGraph® and activPAL®) and heart rate monitors for 7 days. Participants recorded work, non-work, and sleep times in a diary. PA was operationalized as time spent in sedentary behavior, upright time, light, moderate, vigorous, and moderate-to-vigorous PA during work and non-work hours. PA profiles were described and compared with Centers for Disease Control and Prevention aerobic PA guidelines (≥21.4 minute/day) and OPA recommendations (<30 minute/hour upright and intensity of <30% heart rate reserve). Findings: Nineteen male workers (68% White, age = 46.6±7.9 years) were more active on workdays than non-workdays (sedentary: 492.3 vs. 629.7 minute/day; upright: 462.4 vs. 325.2 minute/day; moderate-to-vigorous PA: 72.4 vs. 41.5 minute/day, respectively; all p < .05). Most participants (17/19) achieved aerobic PA guidelines across all days with more achieving on workdays (19/19) than non-workdays (13/19). OPA often exceeded recommended limits with participants accumulating 39.6±12.2 minutes/work hour upright and 30.3±25.9% of working time >30% heart rate reserve. Conclusions/Application to Practice: Male workers reporting high OPA typically met aerobic PA guidelines but exceeded recommended OPA limits. The long-term health implications of such activity profiles should be investigated.

Associations of Sedentary Time with Heart Rate and Heart Rate Variability in Adults: A Systematic Review and Meta-Analysis of Observational Studies.

PURPOSE: To evaluate if sedentary time (ST) is associated with heart rate (HR) and variability (HRV) in adults. METHODS: We systematically searched PubMed and Google Scholar through June 2020. Inclusion criteria were observational design, humans, adults, English language, ST as the exposure, resting HR/HRV as the outcome, and (meta-analysis only) availability of the quantitative association with variability. After qualitative synthesis, meta-analysis used inverse variance heterogeneity models to estimate pooled associations. RESULTS: Thirteen and eight articles met the criteria for the systematic review and meta-analysis, respectively. All studies were cross-sectional and few used gold standard ST or HRV assessment methodology. The qualitative synthesis suggested no associations between ST and HR/HRV. The meta-analysis found a significant association between ST and HR (ß = 0.24 bpm per hour ST; CI: 0.10, 0.37) that was stronger in males (ß = 0.36 bpm per hour ST; CI: 0.19, 0.53). Pooled associations between ST and HRV indices were non-significant (p > 0.05). Substantial heterogeneity was detected. CONCLUSIONS: The limited available evidence suggests an unfavorable but not clinically meaningful association between ST and HR, but no association with HRV. Future longitudinal studies assessing ST with thigh-based monitoring and HRV with electrocardiogram are needed.

Tethered Swimming Test: Reliability and the Association With Swimming Performance and Land-Based Anaerobic Performance.

ABSTRACT: Nagle Zera, J, Nagle, EF, Nagai, T, Lovalekar, M, Abt, JP, and Lephart, SM. Tethered swimming test: reliability and the association with swimming performance and land-based anaerobic performance. J Strength Cond Res 35(1): 212-220, 2021-The purpose of this study was 3-fold: (a) to examine the test-retest reliability of a 30-second maximal tethered freestyle swimming test (TST), (b) to assess the validity of the TST by examining the association with sprint swimming performance, and (c) to examine the associations between a swim-specific and land-based measure of anaerobic performance. A total of 29 male and female swimmers were recruited to participate in the study. Each subject completed a Wingate Anaerobic cycling test (WAnT), 2 or 4 TST, and a 22.9 m (25 yd), 45.7 m (50 yd), and 91.4 m (100 yd) maximal freestyle performance swims (PS). Mean and peak force (Fmean and Fpeak) were recorded for both the WAnT and TST, and average swimming velocity and time were recorded for the PS. In addition, physiological and perceptual measures were recorded immediately postexercise for all tests. The results of the present investigation showed strong intersession and intrasession reliability (R = 0.821-0.975; p < 0.001) for force parameters of the TST. Moderate correlations were found between Fmean and PS time and velocity of all distances, with slightly weaker correlations between Fpeak and the 22.9 m (time and velocity) and 45.7 m (velocity) PS. Finally, moderate correlations were found for Fmean and Fpeak of the TST and WAnT. This study demonstrated that the TST is a reliable measure, with moderate association with swimming performance, producing similar physiological responses compared with free swimming. Therefore, future research should focus on investigating the potential benefits of using the TST as a regular assessment tool as a part of a competitive swimming training program to track adaptations and inform training decisions.

Reliability and Validity of a Pool-Based Maximal Oxygen Uptake Test to Examine High-Intensity Short-Duration Freestyle Swimming Performance.

Nagle, EF, Nagai, T, Beethe, AZ, Lovalekar, MT, Zera, JN, Connaboy, C, Abt, JP, Beals, K, Nindl, BC, Robertson, RJ, and Lephart, SM. Reliability and validity of a pool-based maximal oxygen uptake test to examine high-intensity short-duration freestyle swimming performance. J Strength Cond Res 33(5): 1208-1215, 2019-A modality-specific swimming protocol to assess maximal oxygen uptake (V[Combining Dot Above]O2maxsw) is essential to accurately prescribe and monitor swimming conditioning programs. Consequently, there is a need for a reliable and valid graded intensity swimming pool test to accurately assess V[Combining Dot Above]O2maxsw using indirect calorimetry. The purpose of this study was to assess (a) reliability of an intensity self-regulated swimming pool test of V[Combining Dot Above]O2maxsw and (b) validity of a V[Combining Dot Above]O2maxsw test using performance swim (PS) time as the criterion. Twenty-nine men (n = 15) and women (n = 14) (age, 23 ± 6.4 years; body mass index, 23.5 ± 3.0 kg·m) performed 2 swimming pool V[Combining Dot Above]O2maxsw trials (V[Combining Dot Above]O2maxsw A and V[Combining Dot Above]O2maxsw B), and 2 PS tests (45.7 m [31.20 ± 4.5 seconds] and 182 m [159.2 ± 25.5 seconds]). For test-retest reliability (trials A vs. B), strong correlations (p < 0.05) were found for V[Combining Dot Above]O2maxsw (ml·kg·min) (r = 0.899), O2 pulse (ml O2·beat) (r = 0.833), and maximum expired ventilatory volume (L·min) (r = 0.785). For performance validity, moderately strong correlations (p < 0.05) were found between V[Combining Dot Above]O2maxsw A and 45.7-m (r = -0.543) and 182-m (r = -0.486) swim times. The self-regulated graded intensity swimming pool protocol examined presently is a reliable and valid test of V[Combining Dot Above]O2maxsw. Studies should consider the suitability of a V[Combining Dot Above]O2maxsw test for military personnel, clinical populations, and injured athletes.

Affective and metabolic responses to self-selected intensity cycle exercise in young men.

Self-selected intensity exercise has resulted in greater affective responses (AR) compared to prescribed exercise of similar intensity and many individuals self-select intensity at a moderate level identified by metabolic analysis. As such, self-selected intensity may be an effective alternative for exercise prescription designed to promote adherence and result in health and fitness benefits. Self-selected intensity has not been well described for many subject populations and exercise modes. Therefore, the purpose of this investigation was to measure affective and metabolic responses during self-selected intensity cycle exercise in college-aged men. Thirty-three men (22.4 ±â€¯2.2 yr) performed a peak oxygen consumption test and a 20 min self-selected trial on a cycle ergometer on separate days. Oxygen consumption (VO2) was measured continuously throughout both exercise sessions. AR were measured using the Feeling Scale and ratings of perceived exertion (RPE) using the OMNI Scale every 5 min during the self-selected trial. χ2 analysis was used to determine if a significant proportion of subjects self-selected intensity above 50% VO2 reserve (VO2R), defined as a threshold for moderate-intensity exercise and potential cardiorespiratory fitness benefits by American College of Sports Medicine. Mean self-selected intensity was 57.6 ±â€¯11.1%VO2peak and 89.3 ±â€¯20.2% of ventilatory threshold. Twenty eight of 33 subjects self-selected intensity above 50% VO2R (p < .05). Self-selected intensity was associated with positive AR (1.8 ±â€¯1.4) and mean RPE of 4.0 ±â€¯1.5. In college-aged men, self-selected intensity cycle exercise was performed at a moderate intensity level and elicited positive AR for most subjects. Therefore, self-selected intensity could be an effective component of an exercise prescription for this population.

Identification and Biochemical Characterization of a Novel Protein Phosphatase 2C-Like Ser/Thr Phosphatase in Escherichia coli.

In bacteria, signaling phosphorylation is thought to occur primarily on His and Asp residues. However, phosphoproteomic surveys over the past decade in phylogenetically diverse bacteria have identified numerous proteins that are phosphorylated on Ser and/or Thr residues. Consistently, genes encoding Ser/Thr kinases are present in many bacterial genomes, such as that of Escherichia coli, which encodes at least three Ser/Thr kinases. Since Ser/Thr phosphorylation is a stable modification, a dedicated phosphatase is necessary to allow reversible regulation. Ser/Thr phosphatases belonging to several conserved families are found in bacteria. One family of particular interest are Ser/Thr phosphatases, which have extensive sequence and structural homology to eukaryotic Ser/Thr protein phosphatase 2C (PP2C) phosphatases. These proteins, called eukaryote-like Ser/Thr phosphatases (eSTPs), have been identified in a number of bacteria but not in E. coli Here, we describe a previously unknown eSTP encoded by an E. coli open reading frame (ORF), yegK, and characterize its biochemical properties, including its kinetics, substrate specificity, and sensitivity to known phosphatase inhibitors. We investigate differences in the activity of this protein in closely related E. coli strains. Finally, we demonstrate that this eSTP acts to dephosphorylate a novel Ser/Thr kinase that is encoded in the same operon.IMPORTANCE Regulatory protein phosphorylation is a conserved mechanism of signaling in all biological systems. Recent phosphoproteomic analyses of phylogenetically diverse bacteria, including the model Gram-negative bacterium Escherichia coli, demonstrate that many proteins are phosphorylated on serine or threonine residues. In contrast to phosphorylation on histidine or aspartate residues, phosphorylation of serine and threonine residues is stable and requires the action of a partner Ser/Thr phosphatase to remove the modification. Although a number of Ser/Thr kinases have been reported in E. coli, no partner Ser/Thr phosphatases have been identified. Here, we biochemically characterize a novel Ser/Thr phosphatase that acts to dephosphorylate a Ser/Thr kinase that is encoded in the same operon.

Improvement of Flutter-Kick Performance in Novice Surface Combat Swimmers With Increased Hip Strength.

PURPOSE: To examine strength, range of motion, anthropometric, and physiological contributions to novice surface-combat-swimming (sCS) performance and establish differences from freestyle-swimming (FS) performance to further understand the transition of FS to sCS performance. METHODS: A total of 13 competitive swimmers (7 male and 6 female; 27.7 [2.3] y; 176.2 [2.6] cm; 75.4 [3.9] kg) completed 8 testing sessions consisting of the following: physiological land-based measurements for maximal anaerobic and aerobic capacity and upper- and lower-extremity strength and range of motion, an sCS anaerobic capacity swim test measuring peak and mean force and fatigue index, 2 aerobic capacity tests measuring maximal aerobic capacity for both FS and sCS, and four 500-m performance swims for time, 1 FS, and 3 sCS. Separate multiple linear-regression analysis was used to analyze predictors of both sCS and FS performance models. RESULTS: FS performance was predicted by the final FS maximal oxygen uptake with an R2 of 42.03% (F1,10 = 7.25; P = .0226), whereas sCS performance was predicted by isometric hip-extension peak strength with an R2 of 41.46% (F1,11 = 7.79; P = .0176). CONCLUSIONS: Results demonstrate that different physiological characteristics predict performance, suggesting that an altered strategy is used for novice sCS than FS. It is suggested that this may be due to the added constraints as mandated by mission requirements including boots, weighted gear, and clandestine requirements with hips lowered beneath the surface. Further research should examine the kinematics of the sCS flutter kick to improve performance by developing training strategies specific for the task.

Evaluating Energy Expenditure Estimated by Wearable Technology During Variable Intensity Activity on Female Collegiate Athletes.

Monitoring an athlete's energy intake and energy expenditure (EE) is an important consideration of nutritional planning for sport conditioning and peak performance. In order to provide appropriate recommendations regarding nutritional requirements and caloric needs, an accurate determination of energy requirements is necessary. By knowing an individual's EE, a coach, athletic performance staff or trainer can effectively determine training loads and volumes necessary for periodization and seasonal planning for a particular sport. The purpose of this study is to examine the accuracy of the BodyMedia Mini armband while measuring EE in female basketball players during various-intensity game-like conditions. This investigation required three testing sessions: an orientation session, and two randomized experimental trials. Trials included a maximal multistage 20-m shuttle run (Trial I) and 30-minute basketball skills session (Trial II). The independent variable for this investigation was EE estimated by the Mini armband. The dependent variable was EE determined by the Cosmed K4b2 indirect calorimetry (IC) method. EE assessed with the Mini and EE measured with the IC method was significantly correlated for both Trial I (r= 0.839) and Trial II (r= 0.833). EE calculated by the Mini was significantly underestimated in both Trial I (9.41 ± 26.1 total kcals) and Trial II (56.71 ± 14.1 total kcals). During Trial I the underestimation of EE increased with a rise in test level and intensity (p<.05). Due to the underestimation of EE by the Mini, the development of exercise specific algorithms to improve the estimation of EE during intermittent exercise in basketball players is warranted.

Reliability and Accuracy of a Standardized Shallow Water Running Test to Determine Cardiorespiratory Fitness.

A standardized fitness assessment is critical for the development of an individualized exercise prescription. Although the benefits of aquatic exercise have been well established, there remains the need for a standardized nonswimming protocol to accurately assess cardiorespiratory fitness (CRF) in shallow water. The present investigation was designed to assess (a) the reliability of a standardized shallow water run (SWR) test of CRF and (b) the accuracy of a standardized SWR compared with a land-based treadmill (LTM) test. Twenty-three healthy women (20 ± 3 years), with body mass index (23.5 ± 3 kg·m), performed 2 shallow water peak oxygen consumption (V[Combining Dot Above]O2peak) running tests (SWRa and SWRb), and 1 V[Combining Dot Above]O2max LTM. Intraclass correlation coefficients indicated moderately strong reliability for V[Combining Dot Above]O2peak (ml·kg·min) (r = 0.73, p < 0.01), HRpeak (b·min) (r = 0.82; p < 0.01), and O2pulse (V[Combining Dot Above]O2 [ml·kg·min]·HR [b·min]) (r = 0.77, p < 0.01). Using paired t-tests and Pearson's correlations, SWR V[Combining Dot Above]O2peak and HRpeak were significantly lower than during LTM (p ≤ 0.05) and showed moderate correlations of 0.60 and 0.58 (p < 0.001) to LTM. O2pulse was similar (p > 0.05) for the SWR and LTM tests with a moderate correlation of 0.63. A standardized SWR test as a measure of CRF is a reliable, and to some degree, valid alternative to conventional protocols and may be used by strength and conditioning professionals to measure program outcomes and monitor training progress. Furthermore, this protocol provides a water-based option for CRF assessment among healthy women and offers insight toward the development of an effective protocol that can accommodate individuals with limited mobility, or those seeking less musculoskeletal impact from traditional land-based types of training.

Aquatic High Intensity Interval Training for Cardiometabolic Health: Benefits and Training Design.

High-intensity interval training (HIIT) has emerged as an attractive alternative to traditional continuous exercise training (CT) programs for clinical and healthy populations who find that they can achieve equal or greater fitness benefits in less time. Land-based HIIT may not be an appropriate choice for some participants. Few studies have explored the acute responses and chronic adaptations of HIIT in an aquatic environment, and no study has compared the cardiometabolic responses of an aquatic-based program to a land-based HIIT program. Shallow-water aquatic exercise (AE) programs utilizing HIIT have elicited comparable and, in some cases, greater physiological responses compared with constant-intensity or continuous AE regimens. Factors that may explain why HIIT routines evoke greater cardiometabolic responses than CT protocols may be based on the types of exercises and how they are cued to effectively manipulate hydrodynamic properties for greater intensities. Favorable aquatic HIIT protocols such as the S.W.E.A.T. system may serve as a beneficial alternative to land-based HIIT programs for clinical, and athletic populations, potentially reducing the likelihood of associated musculoskeletal and orthopedic complications. Hence, the purpose of this review is to examine the role of AE as an alternative safe and effective HIIT modality.

Exertional Observation in Adults Performing Intermittent Treadmill Walking and Running.

The present investigation examined the Adult OMNI Walk-Run Scale for use by an independent observer to rate an individual's perception of exertion during intermittent treadmill walking and running. Forty (22.4 ± 2.9 yrs) recreationally active males (n = 18) and females (n = 22) completed three 5-min intermittent bouts of treadmill exercise. The exercise bouts were a level walk (LW; 4.0 km·hr-1, 0% grade), hill walk (HW; 5.6 km·hr-1, 5% grade), and run (R; 8 km·hr-1, 2.5% grade). Each bout was separated by a 5-min recovery period. RPE responses were simultaneously estimated by an observer and self-estimated by the participant during each bout using the Adult OMNI Walk-Run Scale. Session RPE responses were simultaneously estimated by the same observer and self-estimated by the participant 5-min post-exercise session. Analysis of variance indicated no significant mean differences between observer RPE and participant RPE (p > 0.05) except for males during the running bout (p < 0.05). Additionally, there were no significant mean differences between the observer RPE and the participant RPE for the session ratings (p > 0.05). Finally, strong positive correlations were found between observer and participant RPE ranging from 0.79-0.84 for exercise bouts and moderate-strong positive correlations ranging from 0.58-0.64 for the exercise session. Results support the use of the OMNI RPE Scale in a direct observation procedure to estimate exertion in female and male young adults performing intermittent treadmill walking and running. This observation-based procedure provides the practitioner with an opportunity to independently evaluate the perceptual intensity of individuals involved in aerobic exercise.

Energy Drinks Improve Five-Kilometer Running Performance in Recreational Endurance Runners.

Prins, PJ, Goss, FL, Nagle, EF, Beals, K, Robertson, RJ, Lovalekar, MT, and Welton, GL. Energy drinks improve five-kilometer running performance in recreational endurance runners. J Strength Cond Res 30(11): 2979-2990, 2016-The purpose of this study was to evaluate exercise performance time and related physiological and perceptual responses of recreational endurance runners after they had ingested a commercially available energy drink (Red Bull, Red Bull GmbH, Fuschl am See, Austria) containing caffeine, glucose, and taurine. Recreational endurance runners (n = 18; 13 men and 5 women; age: 20.39 ± 3.27 years; weight: 71.25 ± 17.17 kg; height: 178.00 ± 7.57 cm; V[Combining Dot Above]O2max: 55.94 ± 7.66 ml·kg·min) participated in a double-blind, crossover, repeated-measures study where they were randomized to supplement with 500 ml of the commercially available energy drink Red Bull and a noncaffeinated, sugar-free placebo (PLA) 60 minutes before completing a 5-km time trial on a treadmill, separated by 7 days. Heart rate, rating of perceived exertion (RPE) (RPE-Overall; RPE-Chest; RPE-Legs), and affect were recorded at rest, 1 hour before ingestion, at 5-minute intervals during the 5-km time trial, and immediately after exercise. Session RPE and session affect were obtained 5 minutes after completion of the 5-km time trial. The distance covered at each 5-minute interval during the 5-km time trial was recorded. Performance improved with the energy drink compared with placebo (Red Bull: 1,413.2 ± 169.7 vs. PLA: 1,443.6 ± 179.2 seconds; p = 0.016), but there were no differences in RPE, affect, session RPE, session affect, or the distance covered at 5-minute splits between the two 5-km time trials (p > 0.05). These results demonstrate that consuming a commercially available energy drink before exercise can improve 5-km performance. These results may have application for altering pre-exercise nutritional strategies in recreational runners.

Prediction of VO2 peak using OMNI Ratings of Perceived Exertion from a submaximal cycle exercise test.

The primary aim of this study was to develop statistical models to predict peak oxygen consumption (VO2 peak) using OMNI Ratings of Perceived Exertion measured during submaximal cycle ergometry. Male (M = 20.9 yr., SE = 0.4) and female (M = 21.6 yr., SE = 0.5) participants (N = 81) completed a load-incremented maximal cycle ergometer exercise test. Simultaneous multiple linear regression was used to develop separate VO2 peak statistical models using submaximal ratings of perceived exertion for the overall body, legs, and chest/breathing as predictor variables. VO2 peak (L·min(-1)) predicted for men and women from ratings of perceived exertion for the overall body (3.02 ± 0.06; 2.03 ± 0.04), legs (3.02 ± 0.06; 2.04 ± 0.04), and chest/breathing (3.02 ± 0.05; 2.03 ± 0.03) were similar to measured VO2 peak (3.02 ± 0.10; 2.03 ± 0.06, ps > .05). Statistical models based on submaximal OMNI Ratings of Perceived Exertion provide an easily administered and accurate method to predict VO2 peak.

Energy expenditure, cardiorespiratory, and perceptual responses to shallow-water aquatic exercise in young adult women.

INTRODUCTION: Aquatic exercise (AE) is a popular form of physical activity, yet few studies have assessed the individual's energy expenditure (EE) associated with a continuous bout of AE. Studies using indirect calorimetry to measure EE have reported limitations associated with test methodology and the ability to control individual's exercise intensity or tempo. PURPOSE: To evaluate EE and cardiorespiratory (CR) responses during a 40-minute shallow-water AE session in young adult women. METHODS: Twenty-one healthy women (aged 21.7 ± 3.4 years) completed an orientation practice session and a 40-minute shallow-water AE session using a traditional exercise class format and the SWEAT video-based instructional cuing program. The high-intensity interval format included the following segments: 1) warm-up (3 minutes); 2) CR segment ( 22 minutes); 3) muscular endurance segment (ME; 10 minutes); and 4) cool-down (5 minutes). Subject oxygen consumption (VO2; mL/kg/min), heart rate (HR) and OMNI overall ratings of perceived exertion (RPE-O) were assessed each minute. Average kcal/min1, metabolic equivalents (METs; 1 MET = 3.5 mL/kg/min), and total kcals per segment and for the overall session were calculated. RESULTS: The total subject EE throughout the 40-minute trial (including warm-up and cool-down segments) was 264 kcals, with an overall average of 6.3 kcals/min (5.6 METs).The average kcals/min expended throughout CR segments 2 through 6 was 8.05 (7.1 METs), with the Hoverjog segment producing the greatest average kcals/min at 8.3 (7.3 METs). The CR portion (22 min) contributed 65% of the total EE (171 kcals) of the 40-minute AE trial. For the overall AE trial, the highest and average subject VO2 achieved were 33.3 and 19.7 mL/kg/min, respectively. The average highest subject heart rate achieved was 177 beats per minute (bpm), equivalent to 90% of the participant's age-predicted HRmax. CONCLUSION: Energy expenditure during a 40-minute AE session met national recommendations for a daily moderate-to-vigorous bout of physical activity offering a viable alternative to land-based exercise. Because AE serves as a partial-weight bearing modality, future studies are needed to clarify the EE of shallow-water AE in apparently healthy and clinical populations.