not sure...i heard that badminton plays need one of if not the most cardiovascular fitness compared to other sports
I don't think so compared to "cardio only" sports like long distance running, swimming, skiing etc. But Badminton (together with some other sports like wrestling, martial arts etc.) at elite level is extremely challenging as it is BOTH cardio, and explosive strength. Endurance athletes are seldom very strong and explosive, and strong and explosive athletes are seldom very enduring.. it is really hard to train for both explosiveness and endurance..
If you just run etc. you will become to slow.. and if yo train explosiveness, strenght, your muscles will consume too much oxygen, and make your endurance fail..
This combination of strength/endurance is very hard to train for, and olympic badminton player usually score very well on tests, as far as I hev been told in comparison to most other sports athletes.
Of course the stamina/cardio part is less demanding for doubles/mixed and I think todays game puts less stress on the stamina portion after rally scoring was introduced.
But if you would compare Federer (plays Tennis) with Lin Dan fitness, I am pretty sure LD would have extremely better testing values, in leg-strength, agility, speed, and endurance/cardio.
/Twobeer