Aerobic Exercise In Children Research Articles

The muscle pump is not an important determinant of muscle blood flow during exercise.

POINT-COUNTERPOINT COMMENTSThe muscle pump is not an important determinant of muscle blood flow during exercise.Vladimir S Panchev, Adelina V Suvandjieva, and Marieta V PanchevaVladimir S Panchev, Adelina V Suvandjieva, and Marieta V PanchevaPublished Online:01 Aug 2005https://doi.org/10.1152/japplphysiol.00600.2005MoreSectionsPDF (24 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat This letter is in response to the Point-Counterpoint series “The muscle pump is/is not an important determinant of muscle blood flow during exercise” that appeared in the July issue (vol. 99: 371–375, 2005; doi:10.1152/japplphysiol.00381; http://jap.physiology.org/content/vol99/issue1).Letter to Editor: We appreciate the initiative for this topic, which can become a starting point for reconsidering the entire theory of the blood circulation, a purpose that we have sought to achieve in the last two years. Our opinion is that the muscle pump is definitely not an important determinant of muscle blood flow during exercise, although in particular circumstances it can have a net positive effect on it (1). However, we find it difficult to understand the extent to which the muscle pump contribution to muscle blood flow is investigated isolated from the venous supply to the heart, considering that during intensive exercise this flow can reach up to 85% of total blood volume, and also the extent to which this contribution is examined predominantly during dynamic exercise, neglecting the mechanisms that ensure the blood return in the absence of muscle pump, for example, at resting upright posture, in steady-state isometric contraction, or in early passive recovery (2). This may be the key point for the entire confusion in the matter. Is it not conclusive enough that by continuous isometric contraction, “unknown” factors ensure the venous return against the inhibitory action of muscle contraction? Or, which one of both, agonist-antagonist, muscles is the muscle pump motor, considering the generally neutral vein position?Our theory is that the venous return is effectuated through transmural arterial pulsations, arteriovenous anastomoses, and arteriovenous capillary bridges. This ensures the autonomous functioning of the cardiovascular system, independently from the central nervous system, on which the muscle contractions are subordinate.REFERENCES1 Lutjemeier B, Miura A, Scheuermann B, Koga S, Townsend D, and Barstow T. Muscle contraction-blood flow interactions during upright knee extension exercise in humans. J Appl Physiol 98: 1575–1583, 2005.Link | ISI | Google Scholar2 Rowland T and Lisowski R. Determinants of diastolic cardiac filling during exercise. J Sport Med Phys Fitness 43: 380–385, 2003.ISI | Google Scholar Download PDF Previous Back to Top Next FiguresReferencesRelatedInformationCited ByCirculatory “Efficacy” during progressive aerobic exercise in children: insights from the Q: VO2 relationship3 May 2007 | European Journal of Applied Physiology, Vol. 101, No. 1Improved orthostatic tolerance by leg crossing and muscle tensing: indisputable evidence for the arteriovenous pump existenceMarieta V. Pancheva, Vladimir S. Panchev, and Adelina V. Suvandjieva1 October 2006 | Journal of Applied Physiology, Vol. 101, No. 4Lower body negative pressure vs. lower body positive pressure to prevent cardiac atrophy after bed rest and spaceflight. What caused the controversy?Marieta V. Pancheva, Vladimir S. Panchev, and Adelina V. Suvandjieva1 March 2006 | Journal of Applied Physiology, Vol. 100, No. 3 More from this issue > Volume 99Issue 2August 2005Pages 778-778 Copyright & PermissionsCopyright © 2005 the American Physiological Societyhttps://doi.org/10.1152/japplphysiol.00600.2005PubMed16020448History Published online 1 August 2005 Published in print 1 August 2005 Metrics

Immune modulation following aerobic exercise in children with cystic fibrosis.

Previous studies have demonstrated altered immune response following exercise in healthy adults and children. As data are lacking in children with cystic fibrosis, we evaluated the immune response following acute exercise and hypothesized that acute increases in cellular changes would be seen but would be blunted in subjects with CF. Leukocytes, lymphocytes, and their subsets as well as natural killer cell number and activity were determined before, immediately after, and one hour post exhaustive exercise in 15 children with cystic fibrosis (8-21 yrs, FEV1 69.5+/-18.0%, colonized with P aeruginosa) and 15 healthy controls (8-18 yrs, FEV1 107.5+/-10.7%). At baseline the cystic fibrosis group had greater leukocytes (9.25+/-2.83 vs. 5.17+/-0.96 x 10(9) cells/liter). Immediately post exercise, the cystic fibrosis group demonstrated increases in cell counts for leukocytes (32.4%), lymphocytes (61.8%), granulocytes (36.4%), monocytes (76.2%), and natural killer cells (315%). Similar percentage increases were seen in cell counts for the controls (leukocytes: 39.5%, lymphocytes: 78.5%, granulocytes: 32.0%, monocytes: 75.9%, and NK cells: 442%). Natural killer cell activity also increased by 57.9% in the group with cystic fibrosis and by 43.6% in the healthy controls. Except for elevated leukocyte and granulocyte counts, values returned to baseline at one hour post-exercise. In conclusion, the cellular immune response to acute exercise in children with mild to moderate cystic fibrosis appears normal.

Children and Aerobic Exercise: A Review of Cognitive and Behavioral Effects

The current article critically reviews studies involving the cognitive and behavioral effects of aerobic exercise in children. Studies evaluated are those with school children and "normal" groups as well as use of aerobic exercise with clinical or "special" populations. Few studies concurrently measured physiological and psychological changes making it difficult to ascertain the role of fitness in any resulting psychological or behavioral changes. Better descriptions of procedures and monitoring of heartrate levels during exercise to ensure appropriate levels of intensity of exercise are needed. Similarities and differences between results of studies with children and adults are discussed, as well as suggestions for future research directions.

Developmental Aspects of Physiological Function Relating to Aerobic Exercise in Children

The many physiological determinants of exercise performance mature throughout the childhood years. Current research suggests that the improvements in maximal aerobic power which occur as the child ages are an expression of both increased body size and improved function. Absolute VO2max increases during the childhood years in both girls and boys. Average VO2max related to bodyweight, however, remains stable in boys of all ages, while values in girls decline progressively as they grow. VO2 at a given treadmill speed or slope falls during the growing years. This improvement in running economy may explain parallel advances in endurance exercise performance. The explanation for greater running economy with growth is uncertain, but lower step rate, improved running mechanics, and changes in body mass: surface area ratio may play a role.