Document Detail

Effects of gradient and load carried on human haemodynamic responses during treadmill walking.
MedLine Citation:
PMID:  11072773     Owner:  NLM     Status:  MEDLINE    
This study examined the effects of different loads carried and gradients, on haemodynamic and cardiovascular responses during 45 min of treadmill walking. A group of 20 male endurance-trained athletes [mean maximal oxygen uptake 61.4 (SD 4) ml x kg(-1) x min(-1)] volunteered for this study. The subjects took part in three separate trials. The first involved a backpack weighing 25 kg, the second a 35 kg backpack, and the third trial, unladen, while walking on a treadmill at a speed of 5 km x h(-1). The subjects began walking on the treadmill with the randomized load at 0% gradient. After 15 min, the gradient was increased by 5% every 15 min for a total of 45 min. The order of the loads carried was randomized among subjects. No significant differences were noted for all the variables measured attributable to loads between 25 kg and 35 kg. However, significant (P<0.05) differences were seen for all variables each time the gradient was increased. Cardiac output increased from 11.4 (SD 0.6) 1 x min(-1) at 0% to 13.6 (SD 0.8) l x min(-1) at 5% and to 17.6 (SD 1.3) l x min(-1) at 10% carrying the 35 kg load. Similarly, lactic acid concentrations in the blood increased from 2.8 (SD 0.2) to 3.1 (SD 0.6) and to 5.3 (SD 1.3) mmol x l(-1), respectively. Similar changes were observed for all variables while carrying the 25 kg load. In addition, steady states in oxygen uptake and other physiological variables were obtained throughout the course of the tests. These data suggest that during isodynamic exercise, one of the main factors determining metabolic and haemodynamic responses will be the change in gradient and to a lesser extent, the mass of the load carried.
M Sagiv; S Ben-Gal; D Ben-Sira
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Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article    
Journal Detail:
Title:  European journal of applied physiology     Volume:  83     ISSN:  1439-6319     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2000 Sep 
Date Detail:
Created Date:  2001-03-08     Completed Date:  2001-05-31     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  47-50     Citation Subset:  IM    
Sports Medicine and Rehabilitation Division, The Zinman College, Wingate, Israel.
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MeSH Terms
Exercise Test
Heart Rate
Hemodynamics / physiology*
Lactic Acid / blood
Oxygen Consumption
Ventricular Function, Left
Walking / physiology*
Reg. No./Substance:
50-21-5/Lactic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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