Aerobic exercise deconditioning and countermeasures during bed rest. [Review] [153 refs] Authors Full Name Lee, Stuart M C. Moore, Alan D. Everett, Meghan E. Stenger, Michael B. Platts, Steven H. Institution Cardiovascular Laboratory, Wyle Integrated Science and Engineering Group, Houston, TX, USA. Title Aerobic exercise deconditioning and countermeasures during bed rest. [Review] [153 refs] Source Aviation Space & Environmental Medicine. 81(1):52-63, 2010 Jan. Abstract Bed rest is a well-accepted model for spaceflight in which the physiologic adaptations, particularly in the cardiovascular system, are studied and potential countermeasures can be tested. Bed rest without countermeasures results in reduced aerobic capacity and altered submaximal exercise responses. Aerobic endurance and factors which may impact prolonged exercise, however, have not been well studied. The initial loss of aerobic capacity is rapid, occurring in parallel with the loss of plasma volume. Thereafter, the reduction in maximal aerobic capacity proceeds more slowly and is influenced by central and peripheral adaptation. Exercise capacity can be maintained during bed rest and may be improved during recovery with appropriate countermeasures. Plasma volume restoration, resistive exercise, orthostatic stress, aerobic exercise, and aerobic exercise plus orthostatic stress all have been tested with varying levels of success. However, the optimal combination of elements-exercise modality, intensity, duration, muscle groups exercised and frequency of aerobic exercise, orthostatic stress, and supplementary resistive or anaerobic exercise traininghas not been systematically evaluated. Currently, frequent (at least 3 days per week) bouts of intense exercise (interval-style and near maximal) with orthostatic stress appears to be the most efficacious method to protect aerobic capacity during bed rest. Further refinement of protocols and countermeasure hardware may be necessary to insure the success of countermeasures in the unique environment of space. [References: 153] Publication Type Journal Article. Research Support, U.S. Gov't, Non-P.H.S.. Review. Date Created 20100111
Oxygen consumption, heart rate, and blood lactate responses to an acute bout of plyometric depth jumps in college-aged men and women. Authors Full Name Brown, Gregory A. Ray, Michael W. Abbey, Bryce M. Shaw, Brandon S. Shaw, Ina. Institution Human Performance Laboratory, HPERLS Department, University of Nebraska at Kearney, Kearney, Nebraska, USA.
[email protected]. Title Oxygen consumption, heart rate, and blood lactate responses to an acute bout of plyometric depth jumps in college-aged men and women. Source Journal of Strength & Conditioning Research. 24(9):2475-82, 2010 Sep. Abstract Although plyometrics are widely used in athletic conditioning, the acute physiologic responses to plyometrics have not been described. The purpose of this study was to investigate the oxygen consumption, heart rate, and blood lactate responses to a single session of plyometric depth jumps. Twenty recreationally trained college-aged subjects (10 men, 10 women) participated in a single session of 8 sets of 10 box depth jumps from a height of 0.8 m with 3 minutes of passive recovery between each set. Plyometric depth jumping elicited 82.5 +/- 3.1% and 77.8 +/- 3.1% of the measured maximal oxygen consumption (O2max) for women and men, respectively, with no difference in oxygen consumption in ml/kg/min or percent O2max between sexes or sets. Heart rate significantly increased (p < 0.05) from 68.1 +/- 2.9 beatsxmin-1 at rest to 169.6 +/- 1.2 beatsxmin-1 during depth jumping. Sets 5 to 8 elicited a higher (p < 0.05) heart rate (173.3 +/- 1.3 beatsxmin-1) than sets 1 to 4 (164.6 +/- 1.8 beatsxmin-1). Women exhibited a higher heart rate (p < 0.05) during sets 1 and 2 (169.9 +/- 2.8 beatsxmin-1) than men (150.7 +/- 4.4 beatsxmin-1). The blood lactate concentrations were significantly (p < 0.05) increased above resting throughout all sets (1.0 +/- 0.2 mmolxL-1 compared with 2.9 +/- 0.1 mmolxL-1), with no differences between sexes or sets. Plyometric depth jumping significantly increased oxygen consumption, heart rate, and blood lactate in both men and women, but no significant difference was found between the sexes. Plyometric depth jumping from a height of 0.8 m has similar energy system requirements to what Wilmore and Costill termed "Aerobic Power" training, which should enhance O2max, lactate tolerance, oxidative enzymes, and lactate threshold. Publication Type Journal Article. Research Support, Non-U.S. Gov't. Date Created 20100830
10 or 30-s sprint interval training bouts enhance both aerobic and anaerobic performance. Authors Full Name Hazell, Tom J. Macpherson, Rebecca E K. Gravelle, Braden M R. Lemon, Peter W R. Institution Exercise Nutrition Research Laboratory, Faculty of Health Sciences, School of Kinesiology, 2235 3M Centre, The University of Western Ontario, London, ON, N6A 3K7, Canada.
[email protected] Title 10 or 30-s sprint interval training bouts enhance both aerobic and anaerobic performance. Source European Journal of Applied Physiology. 110(1):153-60, 2010 Sep. Abstract We assessed whether 10-s sprint interval training (SIT) bouts with 2 or 4 min recovery periods can improve aerobic and anaerobic performance. Subjects (n = 48) were assigned to one of four groups [exercise time (s):recovery time (min)]: (1) 30:4, (2) 10:4, (3) 10:2 or (4) control (no training). Training was cycling 3 week(-1) for 2 weeks (starting with 4 bouts session(-1), increasing 1 bout every 2 sessions, 6 total). Pre- and posttraining measures included: VO(2max), 5-km time trial (TT), and a 30-s Wingate test. All groups were similar pre-training and the control group did not change over time. The 10s groups trained at a higher intensity demonstrated by greater (P < 0.05) reproducibility of peak (10:4 = 96%; 10:2 = 95% vs. 30:4 = 89%), average (10:4 = 84%; 10:2 = 82% vs. 30:4 = 58%), and minimum power (10:4 = 73%; 10:2 = 69%; vs. 30:4 = 40%) within each session while the 30:4 group performed ~2X (P < 0.05) the total work session(-1) (83-124 kJ, 4-6 bouts) versus 10:4(38-58 kJ); 10:2 (39-59 kJ). Training increased TT performance (P < 0.05) in the 30:4 (5.2%), 10:4 (3.5%), and 10:2 (3.0%) groups. VO(2max) increased in the 30:4 (9.3%) and 10:4 (9.2%), but not the 10:2 group. Wingate peak power kg(-1) increased (P < 0.05) in the 30:4 (9.5%), 10:4 (8.5%), and 10:2 (4.2%). Average Wingate power kg(-1) increased (P < 0.05) in the 30:4 (12.1%) and 10:4 (6.5%) groups. These data indicate that 10-s (with either 2 or 4 min recovery) and 30-s SIT bouts are effective for increasing anaerobic and aerobic performance. Publication Type Journal Article. Date Created 20100812
The effects of heavy continuous versus long and short intermittent aerobic exercise protocols on oxygen consumption, heart rate, and lactate responses in adolescents. Authors Full Name Zafeiridis, Andreas. Sarivasiliou, H. Dipla, K. Vrabas, I S. Institution Exercise Physiology and Biochemistry Laboratory, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki at Serres, Thessaloniki, Serres, Greece.
[email protected] Title The effects of heavy continuous versus long and short intermittent aerobic exercise protocols on oxygen consumption, heart rate, and lactate responses in adolescents. Source European Journal of Applied Physiology. 110(1):17-26, 2010 Sep. Abstract This study compared the physiological responses to heavy continuous (HC), shortintermittent (SI), and long-intermittent (LI) treadmill exercise protocols in non-endurance adolescent males. Nine adolescents (14 +/- 0.6 years) performed a maximal incremental treadmill test followed, on separate days, by a SI [30 s at 110% of maximal aerobic velocity (MAV) with 30 s recovery at 50%], a LI (3 min at 95% of MAV with 3 min recovery at 35%), and a HC (at 83% of MAV) aerobic exercise protocol. VO(2) and HR were measured continuously, and blood samples were obtained prior to and after the protocols. The duration of exercise and the distance covered were longer (p < 0.05) in HC and LI versus SI. All participants reached 80 and 85% of VO(2)peak irrespective of the protocol, while more participants reached 90 and 95% of VO(2)peak in the intermittent protocols (9 and 6, respectively) versus HC (5 and 3, respectively). The time spent above 80 and 85% of VO(2)peak was higher in HC and LI versus SI; the time above 90% was higher only in LI versus SI, and the time above 95% was higher in LI versus HC and SI. The total VO(2) consumed was greater in HC and LI versus SI. Lactate was higher after LI versus HC. In conclusion, when matched for exhaustion level, LI is more effective in stimulating the aerobic system compared to both HC and SI, while HC aerobic exercise appears equally effective to SI. Nevertheless, adolescents have to exercise for a longer time in HC and LI to achieve these effects. Publication Type Comparative Study. Journal Article. Randomized Controlled Trial. Date Created 20100812
Muscle protein synthesis and gene expression during recovery from aerobic exercise in the fasted and fed states. Authors Full Name Harber, Matthew P. Konopka, Adam R. Jemiolo, Bozena. Trappe, Scott W. Trappe, Todd A. Reidy, Paul T. Institution Human Performance Laboratory, Ball State Univ., Muncie, IN 47306, USA.
[email protected] Title Muscle protein synthesis and gene expression during recovery from aerobic exercise in the fasted and fed states. Source American Journal of Physiology - Regulatory Integrative & Comparative Physiology. 299(5):R1254-62, 2010 Nov. Abstract The purpose of this investigation was to assess mixed-muscle fractional synthesis rate (FSR) and the expression of genes involved in skeletal muscle remodeling after aerobic exercise in the fasted and fed states. Eight recreationally active males (25 +/- 1 yr; Vo(2 max): 52 +/- 2 mlkg(-1)min(-1)) performed 60-min of cycle ergometry at 72 +/- 1% Vo(2 max) on two occasions in a counter-balanced design. Subjects ingested a noncaloric placebo (EX-FAST) or a beverage containing (per kg body wt): 5 kcal, 0.83 g carbohydrate, 0.37 g protein, and 0.03 g fat (EX-FED) immediately and 1 h after exercise. FSR was assessed at rest and following exercise with the use of a l-[ring (2)H(5)]-phenylalanine infusion combined with muscle biopsies at 2 and 6 h postexercise. mRNA expression was assessed at 2 and 6 h postexercise via real-time RT-PCR. FSR was higher (P < 0.05) after exercise in both EX-FAST (0.112 +/0.010%h(-1)) and EX-FED (0.129 +/- 0.014%h(-1)) compared with rest (0.071 +/0.005%h(-1)). Feeding attenuated the mRNA expression (P < 0.05) of proteolytic factors MuRF-1 (6 h) and calpain-2 (2 and 6 h) postexercise but did not alter FOXO3A, calpain1, caspase3, or myostatin mRNA expression compared with EX-FAST. Myogenic regulatory factor (MRF4) mRNA was also attenuated (P < 0.05) at 2 and 6 h postexercise in EX-FED compared with EX-FAST. These data demonstrate that a nonexhaustive bout of aerobic exercise stimulates skeletal muscle FSR in the fasted state and that feeding does not measurably enhance FSR between 2 and 6 h after aerobic exercise. Additionally, postexercise nutrient intake attenuates the expression of factors involved in the ubiquitin-proteosome and Ca(2+)-dependent protein degradation pathways. These data provide insight into the role of feeding on muscle protein metabolism during recovery from aerobic exercise. Publication Type Controlled Clinical Trial. Journal Article. Research Support, Non-U.S. Gov't.
Date Created 20101103
Investigating glycogenosis type III patients with multi-parametric functional NMR imaging and spectroscopy. Authors Full Name Wary, Claire. Nadaj-Pakleza, Aleksandra. Laforet, Pascal. Claeys, Kristl G. Carlier, Robert. Monnet, Aurelien. Fleury, Servanne. Baligand, Celine. Eymard, Bruno. Labrune, Philippe. Carlier, Pierre G. Institution Institute of Myology, Paris, France.
[email protected] Title Investigating glycogenosis type III patients with multi-parametric functional NMR imaging and spectroscopy. Source Neuromuscular Disorders. 20(8):548-58, 2010 Aug. Abstract Debranching enzyme deficiency (Glycogen storage disease (GSD) type III) causes progressive muscle wasting myopathy. A comprehensive nuclear magnetic resonance study involving spectroscopy (NMRS) and imaging (NMRI) evaluated status and function of calf muscles in 18 GSDIII patients. At rest, (31)P NMRS showed elevated pH and accumulation of anomalous phosphomonoesters, (13)C NMRS quantified excess glycogen accumulation and NMRI demonstrated progressive fat replacement that paralleled muscle weakness. Multi-parametric functional NMR, performed at recovery from a single bout of aerobic exercise, simultaneously assessed oxidative phosphorylation from (31)P NMRS, muscle perfusion and BOLD, a marker of blood oxygenation, from arterial spin labeled NMRI, and oxygen uptake from deoxymyoglobin proton NMRS. While blocked glycogenolysis caused inadequate substrate supply to the mitochondria, combined measurements suggested that altered perfusion was also responsible for impaired post-exercise phosphocreatine recovery and could contribute to exercise intolerance in GSDIII. These non-invasive investigations provide new indices to quantify the progression of GSDIII. 2010 Elsevier B.V. All rights reserved. Publication Type Journal Article. Research Support, Non-U.S. Gov't. Date Created 20100803
Relationship between different measures of aerobic fitness and repeated-sprint ability in elite soccer players. Authors Full Name da Silva, Juliano F. Guglielmo, Luiz G A. Bishop, David. Institution Physical Effort Laboratory, Sports Center, Federal University of Santa Catarina, Florianopolis, Brazil.
[email protected] Title Relationship between different measures of aerobic fitness and repeated-sprint ability in elite soccer players. Source Journal of Strength & Conditioning Research. 24(8):2115-21, 2010 Aug. Abstract The main purpose of this study was to investigate the relationship between physiological variables related to aerobic fitness (maximal oxygen uptake: VO2max; the minimum velocity needed to reach VO2max: vVO2max; velocity at the onset of bloodlactate accumulation: vOBLA) and repeated sprint ability (RSA) in elite soccer players. Twenty-nine Brazilian soccer players (17.9 +/- 1.0 years; 178.7 +/- 5.2 cm; 73.6 +/- 6.7 kg; 11.1 +/- 1.3% body fat) from 2 national level teams (A, B) took part in the study. Subjects first performed an incremental test on a treadmill to determine their VO2max, vVO2max and vOBLA. After at least 48 hours, subjects performed an RSA test consisting of 7 34.2-m sprints interspersed with 25 seconds of active recovery, to determine the mean time (MT), the fastest time (FT) and the Sprint decrement (Sdec). Pearson product moment correlations and multiple regressions were used to assess the relationship between aerobic fitness and RSA variables (FT, MT, Sdec, [La] Peak). An analysis of variance, followed by a post hoc test (Tukey), was used to compare the 7 sprints of the RSA test. The level of significance was set at p < 0.05. A significant negative correlation was found between both vOBLA and vVO2max and MT during the RSA test (r = -0.49, p < 0.01; r = -0.38, p < 0.05, respectively). There were also negative correlations between Sdec and vOBLA (r = -0.54), vVO2max (r = -0.49) and VO2max (r = -0.39). The multiple regression revealed that the aerobic (vOBLA) and anaerobic (FT) components explained approximately 89% of the variance of MT. The results of this study demonstrated that RSA is more strongly correlated with vOBLA and vVO2max than the more commonly measured VO2max. Publication Type Journal Article. Date Created 20100804
Effect of warm-ups involving static or dynamic stretching on agility, sprinting, and jumping performance in trained individuals. Authors Full Name Chaouachi, Anis. Castagna, Carlo. Chtara, Moktar. Brughelli, Matt. Turki, Olfa. Galy, Oliver. Chamari, Karim. Behm, David G. Institution Tunisian Research Laboratory Sport Performance Optimization, National Center of Medicine and Science in Sports, Tunis, Tunisia.
[email protected] Title Effect of warm-ups involving static or dynamic stretching on agility, sprinting, and jumping performance in trained individuals. Source Journal of Strength & Conditioning Research. 24(8):2001-11, 2010 Aug. Abstract The objective of the present study was to investigate the effects of static and dynamic stretching alone and in combination on subsequent agility, sprinting, and jump performance. Eight different stretching protocols: (a) static stretch (SS) to point of discomfort (POD); (b) SS less than POD (SS
Medium chain acylcarnitines dominate the metabolite pattern in humans under moderate intensity exercise and support lipid oxidation. Authors Full Name Lehmann, Rainer. Zhao, Xinjie. Weigert, Cora. Simon, Perikles. Fehrenbach, Elvira. Fritsche, Jens. Machann, Jurgen. Schick, Fritz. Wang, Jiangshan. Hoene, Miriam. Schleicher, Erwin D. Haring, Hans-Ulrich. Xu, Guowang. Niess, Andreas M. Institution Central Laboratory, Division of Clinical Chemistry and Pathobiochemistry, University Hospital Tuebingen, Tuebingen, Germany.
[email protected] Title Medium chain acylcarnitines dominate the metabolite pattern in humans under moderate intensity exercise and support lipid oxidation. Source PLoS ONE [Electronic Resource]. 5(7):e11519, 2010. Other ID Source: NLM. PMC2902514 Abstract BACKGROUND: Exercise is an extreme physiological challenge for skeletal muscle energy metabolism and has notable health benefits. We aimed to identify and characterize metabolites, which are components of the regulatory network mediating the beneficial metabolic adaptation to exercise. METHODOLOGY AND PRINCIPAL FINDINGS: First, we investigated plasma from healthy human subjects who completed two independent running studies under moderate, predominantly aerobic conditions. Samples obtained prior to and immediately after running and then 3 and 24 h into the recovery phase were analyzed by a nontargeted (NT-) metabolomics approach applying liquid chromatography-qTOF-mass spectrometry. Under these conditions medium and long chain acylcarnitines were found to be the most discriminant plasma biomarkers of moderately intense exercise. Immediately after a 60 min (at 93% V(IAT)) or a 120 min run (at 70% V(IAT)) a pronounced, transient increase dominated by octanoyl-, decanoyl-, and dodecanoylcarnitine was observed. The release of acylcarnitines as intermediates of partial betaoxidation was verified in skeletal muscle cell culture experiments by probing (13)Cpalmitate metabolism. Further investigations in primary human myotubes and mouse muscle tissue revealed that octanoyl-, decanoyl-, and dodecanoyl-carnitine were able to support the oxidation of palmitate, proving more effective than L-carnitine. CONCLUSIONS: Medium chain acylcarnitines were identified and characterized by a functional metabolomics approach as the dominating biomarkers during a moderately intense exercise bout possessing the power to support fat oxidation. This physiological
production and efflux of acylcarnitines might exert beneficial biological functions in muscle tissue. Publication Type Clinical Trial. In Vitro. Journal Article. Research Support, Non-U.S. Gov't. Date Created 20100716
Effects of high intensity exercise on biventricular function assessed by cardiac magnetic resonance imaging in endurance trained and normally active individuals. Authors Full Name Scott, Jessica M. Esch, Ben T. Haykowsky, Mark J. Paterson, Ian. Warburton, Darren E R. Chow, Kelvin. Cheng Baron, June. Lopaschuk, Gary D. Thompson, Richard B. Institution University of British Columbia, Vancouver, BC, Canada.
[email protected] Title Effects of high intensity exercise on biventricular function assessed by cardiac magnetic resonance imaging in endurance trained and normally active individuals. Source American Journal of Cardiology. 106(2):278-83, 2010 Jul 15. Local Messages The Eisenberg Medical Library has 1969-Present Abstract Although several investigations have demonstrated that prolonged aerobic exercise results in decreased left ventricular (LV) function, few have examined the impact of an acute bout of high-intensity exercise on right ventricular (RV) and LV systolic and diastolic function. Cardiac magnetic resonance imaging with tagging was used to study the impact of high-intensity interval exercise on biventricular function in 9 endurancetrained (ET; Vo(2)max 69 +/- 7 ml/kg/min) and 9 normally active (NA; Vo(2)max 44 +/- 9 ml/kg/min) men. Subjects underwent baseline cardiac magnetic resonance imaging assessments (pre) and then performed an average of 14 1-minute intervals at 97 +/11% (NA) and 99 +/- 6% (ET) of peak power output, separated by 2 minutes of recovery at 21 +/- 6% (NA) and 21 +/- 9% (ET) of peak power output. After exercise, 2 cardiac magnetic resonance imaging assessments (post 1 at 6.2 +/- 2.6 minutes and post 2 at 38.4 +/- 3.8 minutes) were completed. RV and LV ejection fractions, twist, basal and apical rotation rates, rate of untwisting, circumferential strain, and timings were examined. No significant change in RV and LV ejection fractions, twist, untwisting rate, or strain after exercise occurred in the NA group. In the ET group, RV ejection fraction (pre 56 +/- 4%, post 1 54 +/- 4%, post 2 54 +/- 3%) and LV ejection fraction (pre 62 +/4%, post 1 59 +/- 4%, post 2 58 +/- 4%) were decreased at post 1 and post 2, while untwisting rate, apical rotation rate, and circumferential strain were decreased at post 2 (all p values
