Introduction: The relationshipsofdistance per stroke (Os) and stroke rate (SR) with velocity (v)progression,over a range of swimming intensities within aerobic energy supply, did not evidence how Ds and SR slopes (Ds51ope and SRslope' as well as, the crossing point (Cp) between them)change their profiles during maximal aerobic test, and what is the parameter of endurance capacity (among gas exchange threshold (GET), respiratory compensation point (RCP), maximal oxygen uptake (V0 2 max), and economy (e)) that correlates better to these changes. Purpose: the aimed was to highlight the physiological responses associated to Ds and SR changes as swimming velocity increases. Even, analyze if Ds and SR are reliable indices to the control of training and/or improvements in aerobic pace. Methods: Nine subjects performed a continuous incremental test (300m per stage) until volitional exhaustion. Eachstagewas designed by percentages of the maximal crawl velocity in 400m (%v400). VO2max, GET and RCP were examined. The velocities corresponding to VO2 max (vVO2 max), GET (vGET) and RCP (vRCP) were identified. SR was determined from the time taking to complete three strokes. Ds was calculated from equation v = Ds x SR. A second order polynomial function was applied to adjust Ds (y) and SR (y) to v and VO2 (x). The slopes were determined in x (-b/2a) and y (-D/4a, where D = b2-4ac) given vDsslope' vSRslope' VO2DSslope' and VO2SR, slope· The v and VO2 at Cp (vCp and VO2Cp) were determined from the intersection point of the adjusted algorithms. VO2 (y) and v (x) was adjusted from a power function (f(y) = xn). Economy was quantified at vDs,slope, vSR, 1ope' and vCp by means of VO2 and the caloric coefficient for VO2 (20.1kJ). Results: Taking values of VO2max (4458 ± 645 ml/min ) as reference of maximal aerobic rate pace, GET and RCP were locating at 63 and 77% of VO2max, and VO2Cp, VO2 Ds, slope and VO2SR, 1opewere observed to be located at 122%, 68% and 49% of VO2 max, respectively. These results mean that swimming intensity paced by V=2Cp would require great anaerobic demand, since it was located above aerobic maximal rate pace, and that VO2 Ds,1opeand VO2SR, 1ope are reliable indexes of aerobic pace, but they could not be used interchangeable. VO2Ds,1opeseems to be appropriated to develop endurance capacity, since it located swimming intensity in heavy domain of exercise, while VO2SRslopeparameterises the moderate domains of exercise, which is better applied between high intensity sections of training or to pace active rest. The economy from expected VO2 at vDs, slope (0.84 ± 0.18kJ/m ) and vSRslope (0.68 ± 0.16kJ/m ) evidenced correlations with GET (r = 0.76 and 0.70, respectively), but at vCp (1.13 ± 0.19kJ/m ) none correlations were observed. Conclusions: Thus, Ds and SR showed an independent turn point profile for VO2 response, as swimming velocity increases. Moreover, Ds and SR influenced better the swimming velocity at GET than at RCP, showing that GET is the metabolic reference beyond which stroke profile could not ensure an economic pace.
© Copyright 2014 XIIth International Symposium for Biomechanics and Medicine in Swimming. Published by Australian Institute of Sport. All rights reserved.