There was a higher correlation between SWT walk distance and pVO2 than between 6MWT walk distance and pVO2 ( r = 0.866 and 0.765 , respectively ; P < 0.05 ) , and a higher correlation between SWT walk distance and VO2 at AT than between 6MWT walk distance and VO2 at AT ( r = 0.775 and 0.587 , respectively ; P < 0.05 ) .