The purpose of this study was to evaluate the specificity of maximal oxygen uptake (VO2max) and the dynamic response of oxygen uptake (VO2) to sinusoidal work load in distance runners and in American-football players. Sinusoidal work load during ergometer cycling was carried from 30 W to 60% to VO2max (60% VO2max) for a 2 min period. VO2 was measured by the breath-by-breath method. The subjects were 10 distance runners (DRs), 10 American-football players (AFPs), and 11 untrained men (UTM). Mean VO2max was 64.4 mL kg-1 min-1 in the DRs, 53.1 mL kg-1 min-1 in the AFPs and 47.3 mL kg-1 min-1 in the UTM. The fundamental amplitudes of the VO2 response, normalized by dividing by steady state VO2 at 60% VO2max, were similar in the AFPs (20.3%) and the UTM (19.5%), and both were significantly less than in the DRs (25.5%). Phase shift to work load expressed in degrees was similar in the AFPs (87.7 degrees) and UTM (88.0 degrees), but significantly greater than in the DRs (80.4 degrees). HR dynamics in all three groups were similar to a dynamic VO2 response. These findings suggest that development of the dynamic VO2 response and higher VO2max is achieved in the DRs. They also suggest that despite the higher VO2max in the AFPs there is no improvement in the dynamic VO2 response. The results of the present study demonstrate that athletes participating in different sports have characteristic dynamic VO2 responses during cycling exercise.

No abstract

No abstract

No abstract

This sω dy was oonducted to clarify the re且 ationship between skin blood f 璽 ow and sweating during exerdse ， and also to determine the relationship between those thermoregulatory respOnses and Changes in cardiac tirne intervals during exercise ． Six healthy rnales − perform 〔 虹 bicycle exercise at 4096 VO2 max for 40・ min at an ambient temperature of 28°C ( 50％ RH ) ． Physiological parameters including esophageal temperature ( Tes ) ， f sweati rate ( thsw ) ， forearm skin blood flow( LDF ) and cardiac time intervals were measured ． 1) Tes threshold for initiation of cutaneeus vasodilation was higher than that of sweating in each subject ． 2) 【hsw increased with Tes ， while the increase of LDF levded off at 38， 1°C as a breaking po 童 nt ( bp) ． 3 ) When Tes was between 37． 6 − 38． 1°C ， total electrornechanica 且systo苴 e ( QS2)shortened continuously ， but diastolic time ( DT ｝ remained constant ． When Tes was higher than 38． 1°C ， the rate of shortening of DT was larger than that of QS2 ， The pattern of change of 1eft ventricular ejection time ( LVET ) was similar to that of QS2 ． 4 ) The tmugll was formed in the ratio of QS2 to DT ( QS2 ／ DT ) at the bp． When Tes was higher than the bp， the rates of increase were slightly less in the ratio of preejection periOd to LVET ( PEP ／LVET ) and the ratio of electrical systo 且 e to QS2 ( QT ／QS2) ． From these findings ， the fo且 lowing conclusions were obtained ； Tes threshold of skin blood fiow is higher than that of sweating ． A bp is formed for skin blood flow bロt not sweating during exercise in a warm envirenment ． It is suggested that there is ainterrelationship between the control of skin blood fiow and the change ef cardiac function because the specific changes of cardiac interval time are at the bp of LDF ． Key words ： swea 血 9， skin b且 ood fiow， body temperature ， cardiac time interval