You can fix that by setting the second parameter for single_cat_title() to false, which then returns the title instead of echoing it (before the <title> tag), like so:
$title = sprintf('%1$s Race Calendar', single_cat_title( '', false ) );
You can fix that by setting the second parameter for single_cat_title() to false, which then returns the title instead of echoing it (before the <title> tag), like so:
$title = sprintf('%1$s Race Calendar', single_cat_title( '', false ) );