those guys suggesting the massive sit ups and super long distance running are mocking the whole heath myth industry, you DO NOT run 5 miles a day to cut fat, you DO NOT do 3024240 situps to get a six pack
running that kind of distance makes your body consume muscle for fuel, ever notice the physiques of long distance runners? most are weak and thin and emaciated, oh but still have guts
you can only accsess fat for fuel at a certain rate and then you switch over the muscle, DO NOT do such crazy cardio for fat loss once again its an urban legend/myth of the fitness industry lol
try HIIT 10 mins a day, if you can do that up it to 15, that will burn more fat than running for alot longer and wont cause you to consume all your muscle tissue
now on to the six pack EVERYONE has a six pack, i know this may come as a shock to you, but we all have the same damned sheet of muscle in our abdomen
the way to get to seeing it is to cut body fat, and mabye do some weight training on your RA to get it to grow .
so PLEASE do not run 5 miles 4 days a week unless you want to loose your muscle mass, and dont do 500 situps a day unless you want sore small abs that dont show anyways, sure low intensity cardio burns fat too, but higher intensity stuff burns it faster, and that 135 BPM for your heart rate being the "fat burning zone" is also health industry myth bs