Expiratory Flow-Limitation and Resting Pulmonary Function During Maximal Exercise in Young Competitive Swimmers

CONCLUSIONS: Modifying the elementary school recess environment by introducing a fresh fruit snack substantially reduced the consumption of outside unhealthy foods and beverages and increased the amount of MVPA. B-64 Thematic Poster - Respiratory and Cardiovascular Exercise Responses in Children JUNE 1, 2011 3:15 PM - 5:15 PM ROOM: 101 611 Chair: J. Richard Coast, FACSM. Northern Arizona University, Flagstaff, AZ. (No relationships reported) 612 Board #1 3:15 PM - 5:15 PM Respiratory Muscle Function and Ventilatory Patterns in Adolescent Males Martin R. Lindley1, Max Garrard2, Denise Roche3, Piers Barker4, Thomas W. Rowland5, Viswanath B. Unnithan, FACSM6. 1Loughborough University, Loughborough, United Kingdom. 2Leeds Metropoliton University, Leeds, United Kingdom. 3Liverpool Hope University, Liverpool, United Kingdom. 4Duke University Medicial Center, Durham, NC. 5Baystate Medical Center, Springfield, MA. 6Staffordshire University, Stoke on Trent, United Kingdom. Email: m.r.lindley@lboro.ac.uk (No relationships reported) Respiratory muscle function has become prevalent within the literature recently, with specific reference to both disease and athletic populations however, there is limited data pertaining to the healthy and recreationally active adolescent population. PURPOSE: The aim of this study was to investigate the relationship between Inspiratory and Expiratory Muscle strength and pulmonary function at rest and during peak exercise, in an adolescent population. METHODS: Fourteen healthy recreationally active males (age 17 +/- 0.9 yrs; stature 1.81 +/-0.76m; body mass 72.0+/-8.8kg) provided informed written parental permission and subjects’ assent. The study was approved by institutional research ethics committee. In an initial lab visit each subject underwent full familiarisation with all testing protocols. In a second lab visit subjects completed resting pulmonary function (FVC FEV1.0)[Micro-Loop, micro medical UK] and respiratory muscle function (Maximal Inspiratory Pressure: MIP; Maximal Expiratory Pressure: MEP)[Micro-RPM, micro medical UK]. Subjects then pedalled in the upright position at a cadence of 60 rpm on an electronically braked cycle ergometer (Excalibur Sport 925900; Lode, Groningen, Netherlands). Initial and incremental loads of 40 Watts were applied at 4-min intervals for two stages then reduced to 3-min stages of 40 Watt increments to the point of exhaustion (the point when pedal cadence could no longer be maintained). Gas exchange values were obtained using standard open-circuit techniques (Zan 600; nSpire Health Oberthulba, Germany) while minute ventilation was assessed via pneumotachometer. RESULTS: Resting values were considered normal, FVC (5.72 +/-0.85L) FEV1.0(4.79 +/- 0.94L) MIP (114 +/- 25cmH20) MEP 112 +/-31cmH20) VE (9.96 +/1.89L) Bf (16+/- 3) TV (0.72 +/-0.22L). Peak Exercise values were also regarded as normal VE peak (124.25 +/-25.14L) Bfpeak (46+/- 10 breaths) TVpeak (2.76+/0.42L) VO2peak (44.8 +/- 4.6ml/kg/min). The only significant correlation that occurred was between MIP and VE peak (r = 0.60; p<0.05). CONCLUSIONS: Respiratory muscle strength, in the form of MIP is positively correlated with VEpeak in recreationally active adolescent subjects. However there does not appear to be any further relationship between MIP, MEP and ventilation at rest or peak exercise. 613 Board #2 3:15 PM - 5:15 PM High-Intensity Interval Training Improves Airway Health in Inactive Non-asthmatic Children Sara K. Rosenkranz1, Richard R. Rosenkranz2, Tanis J. Hastmann1, Craig A. Harms, FACSM1. 1Kansas State University, Manhattan, KS. 2 University of Western Sydney, Penrith South DC, Australia. Email: S.Rosenkranz@uws.edu.au (No relationships reported) PURPOSE: The relationship between physical activity and airway health in children is not well understood. The purpose of this study was to determine whether eight weeks of high-intensity exercise training would improve the airway health of inactive, non-asthmatic prepubescent children. METHODS: Sixteen healthy, prepubescent children were tested (training group [TrG] n=8, control group [ConG] n=8). Subjects wore accelerometers for seven days prior to the 8-week training period to determine activity level. Prior to and following eight weeks of training (or no training), subjects completed pulmonary function tests (PFTs) including forced expiratory flow in 1-sec (FEV1), forced vital capacity, forced expiratory flow at 25-75% of vital capacity (FEF25-75), exhaled nitric oxide (eNO), and impulse oscillometry (IOS). Subjects also completed an incremental cycle VO2max test, eucapnic voluntary hyperventilation (EVH), anthropometric tests, and blood tests to determine fasting blood glucose, total cholesterol, HDL, LDL, and triglycerides. Body composition was determined using dual-energy x-ray absorptiometry (DXA) pre-training and bioelectrical impedance analysis (BIA) pre- and post-training. RESULTS: There were no differences (p>0.05) in anthropometric measures or PFTs between TrG and ConG at baseline. In the TrG, there was a significant increase in VO2max (~24%), and a decrease in total cholesterol (~13%) and LDL cholesterol (~35%) following training. Additionally, we found improvements (p<0.05) in ∆FEV1 both post-exercise (pre: -7.60±2.10%, post: -1.10±1.80%) and post-EVH (pre: -6.71±2.21%, post: -1.41±1.58%) with training. The change in FEF25-75 pre-post exercise also improved with training (pre: -16.10±2.10%, post: -6.80±1.80%; p<0.05). Lower baseline body-fat percentages were associated with greater improvements in ∆FEV1 following training, and controlling for VO2max lean body mass did not change this association (r=-0.80, p<0.05). CONCLUSION: These results suggest that physical inactivity negatively impacts airway health in non-asthmatic prepubescent children, which can be improved with high-intensity training. However, increased body fat may constrain these improvements. 614 Board #3 3:15 PM - 5:15 PM Expiratory Flow-Limitation and Resting Pulmonary Function During Maximal Exercise in Young Competitive Swimmers Kosuke Kojima, Daniel P. Wilhite, Brian V. Wright, Joel M. Stager, FACSM. Indiana University, Bloomington, IN. Email: kokojima@indiana.edu (No relationships reported) Expiratory flow limitation (EFL) during high-intensity exercise is prevalent in prepubescent children regardless of sex, anthropometric characteristics, and physical activity/training status. However, very limited data on EFL is available for prepubescent competitive swimmers. Although hypothesized as being different, static and dynamic pulmonary measures in competitive swimmers are poorly documented. 25 Copyright © 2011 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited. PURPOSE: To characterize pulmonary function in young competitive swimmers in order to gain additional insight into the influence of swim training on breathing in prepubescent children. METHODS: Eight healthy young competitive swimmers (4 boys and 4 girls; 10.7 ± 0.8 years old; 146.6 ± 6.5 cm; 41.1 ± 7.8 kg) completed a set of resting pulmonary function tests including maximal flow-volume (MFV) maneuvers preceding and following an incremental exercise test to exhaustion on a cycle ergometer. During exercise, oxygen uptake (VO2), ventilation (VE), and EFL were measured. The degree of EFL was determined by the percentage of the exercise tidal volume corresponding to an infringement of the expiratory portion of the MFV loop. In order to compare our data with reported values of agematched untrained prepubescent children (Nourry et al., 2005), a one sample t-test was used. RESULTS: Forced vital capacity and forced expiratory volume in 1 second (FEV1) were 2.66 ± 0.52 liters and 2.40 ± 0.42 liters, respectively. At maximal -1 -1 -1 exercise, expiratory reserve volume (ERV) was 0.91 ± 0.29 liters. VO2max and VEmax were 44.0 ± 6.2 (ml·kg ·min ) and 69.3 ± 18.6 (l·min ), respectively. FEV1, ERV, and VO2max in young swimmers were significantly higher than reported values of untrained prepubescents (p < 0.01). Only three subjects demonstrated a substantial amount of EFL (59, 48, and 18%) during maximal exercise, while five of the eight young swimmers did not present EFL. CONCLUSION: Pulmonary function and ventilatory and metabolic measures in young swimmers are not in agreement with those in untrained prepubescents. The young swimmers in this study showed less prevalence of EFL (3/8, 37.5%) than previous reports (56~95%). Therefore, our data suggest that tidal flowvolume relationships during maximal exercise in prepubescent swimmers differ from those of non-swimmers. 615 Board #4 3:15 PM - 5:15 PM Endothelium-Independent Dilation In Adolescents Kara L. Marlatt, Meghan C. McCue, Aaron S. Kelly, Andrea M. Metzig, Julia Steinberger, Donald R. Dengel, FACSM. University of Minnesota, Minneapolis, MN. Email: marla010@umn.edu (No relationships reported) Vascular function in the brachial artery is assessed with endothelium-dependent dilation (EDD) by reactive hyperemia and endothelium-independent dilation (EID) after sublingual nitroglycerin (NTG) administration. Peak brachial artery dilation post-NTG administration occurs between 3 and 5-min in adults. The time to peak dilation response post-NTG in adolescents is unknown. PURPOSE: To identify the time to peak dilation response to a single dose of sublingual NTG in adolescents. METHODS: EID was measured in 198 healthy (113 males, 85 females) adolescents, age 6-18 years (mean age 13.9 ± 0.2 yrs) via high-resolution ultrasound imaging of the brachial artery. A single dose of 0.3 mg NTG was administered and beat-by-beat ultrasound images were recorded over a 5-min period. The peak diameter following NTG administration was reported relative to baseline as a percentage increase. Tanner stage was determined by trained pediatricians. RESULTS: Mean time to peak EID was 4-min, 28-sec following NTG administration, with no significant difference between genders. There was a significant (p<0.001) difference between brachial EID post-NTG at the 3 vs. 4-min, 4 vs. 5-min, and 3 vs. 5-min time points. Time to peak EID (268.2 ± 2.6 vs. 266.2 ± 3.1 sec, p=0.6), as well as peak EID (24.8 ± 0.5 vs. 25.3 ± 0.6 %, p=0.6) and Tanner stage (3.7 ± 0.1 vs. 4.3 ± 0.1, p=0.3) were not significantly different after accounting for baseline diameter. CONCLUSION: Peak arterial dilation in response to NTG administration occurs between 4 and 5-min in adolescents. The results of this study demonstrate the importance of measuring EID up to 5-min post-NTG administration, as measuring up to only 3-min will likely underestimate artery dilation capacity in adolescents. 616 Board #5 3:15 PM - 5:15 PM The Effects Of 4-weeks Of Supervised Exercise On Vascular And Hemodynamic Function In Adolescent Children Hannah E. Crawford. Appalachian State University, Boone, NC. (No relationships reported) H Crawford , J. Welsh, M Meucci, CD Curry, H Wheeler, C Cook, SR Collier. Appalachian State University, Vascular Biology and Autonomic Studies Laboratory, Boone, North Carolina BACKGROUND: Pediatric obesity is increasing in the United States at an alarming rate. Physical activity is recommended for reducing the risk factors of pediatric obesity, yet no intervention has shown promise at reducing cardiovascular risk. Improvement in the elasticity of the vasculature has been shown to decrease blood pressure and provide cardioprotection from cardiovascular disease, yet there is little data to suggest children can improve their vascular distensibility. PURPOSE: The aim of the current study was to examine the effects of 4 weeks of supervised physical activity on central pressures and vascular function in young children. METHODS: 6 young subjects (3 males, 3 females, age 10 +/- 1.5 years, body fat 21 ± 3.6%) were recruited into a local supervised summer activity program. Each subject performed supervised play-based activities such as hiking, soccer and theraband resistance activity for 5 days per week, 6 hours a day during summer camp. Pre and post-training measurements included pulse wave velocity (PWV), augmentation index (AIx), VO2peak, and seated resting blood pressure. RESULTS: AIx decreased significantly (20.3 ± 12.3 to 11.1 ± 9.9%, p=0.029) following training and whole body arterial stiffness (carotid to dorsalis pedis) decreased (7.9 ± 1.6 to 6.4 ± 0.3 m/s, p=0.025). CONCLUSION: These data show that 4 weeks of supervised exercise elicit cardioprotective benefits on the central pressures and vascular function in adolescent males and females suggesting functional remodeling in 4 weeks of supervised activity. 617 Board #6 3:15 PM - 5:15 PM The Effect of Supervised Activity on Cardiovascular Function in Overweight Children Marco Meucci1, Chelsea Curry2, Hannah Wheeler2, Hannah Crawford2, Carol Cook2, Scott R. Collier2. 1University of Rome “Foro Italico”, Rome, Italy. 2Appalachian State University, Boone, NC. (Sponsor: Alan C. Utter, FACSM) Email: marco.meucci@uniroma4.it (No relationships reported) The cardiovascular and vascular effects of aerobic and resistance exercise training are well known in adults, yet there is a paucity of literature in children. Aerobic exercise is recommended for reducing the risk factors of cardiovascular disease (CVD) however the adolescent child may spend their entire summer school break being sedentary, deriving no cardioprotective benefits when compared to a supervised break filled with play-based activities. PURPOSE: To compare the effects of 4 and 8 weeks of supervised physical activity vs. no intervention on cardiovascular function in young overweight children. METHODS: 22 overweight subjects (body fat 27.4±8.4%, mean age 10.1±1.3 years) were divided into 4 (4w, n=6) and 8 week (8w, n=6) activity groups and unsupervised summer break controls (C, n=10). The 4w and 8w groups performed supervised play-based activity 5 days per week, 6 hours a day with sport and 26 Copyright © 2011 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.