Mike Chang is a fitness superstar for the 21st century.

Gone are the days of Billy Blanks workout tapes and Sweatin' to the Oldies VHS collections. Here is the time of a YouTube channel with more than 2.3 million subscribers, awaiting weekly tips and workouts from the man who founded his own mega-successful fitness and nutrition company, Six Pack Shortcuts.

Recently, Chang put his physique to extra work, attempting some Guinness World Records fitness titles for the guys at SportsManias. He successfully broke the records for most pullups in one minute wearing a 40 lb pack with 13 and most knuckle pushups performed in one minute with 45 (see videos below).

Afterward, we caught up with Chang to ask him the secrets to his record-breaking body, how he trained for these records, and what advice he has to offer those looking to top his numbers.

For all the latest amazing record-breaking videos, make sure to subscribe at YouTube.com/GuinnessWorldRecords.