I read a discussion on Usenet many years ago about weight training. A post described how they measured the stomach muscles' pressure on the intestines. Someone

I read a discussion on Usenet many years ago about weight training. A post described how they measured the stomach muscles' pressure on the intestines. Someone asked "How do they get anyone to do heavy squats with a pressure sensor up their ass?!" The answer was just two words -- "grad students". (A favorite anecdote.)