If I run REALLY HARD on a treadmill for 2 and a half hours, nonstop, will my thighs be smaller in 3 days?

your legs will be too sore to do the simple task of standing up after sitting down. running really hard on a treadmill for 2.5 hours, nonstop, would put you in so much pain & might be to much stress for you especially if you don't normally run the treadmill on a regular basis to slowly build up your endurance & strength to run for that length of time.

No, it will take more than 2 1/2 hour running on the treadmill, plus that is not very safe either.

You will only be smaller depending on the food you eat and what part of your body loses fat fastest. I reccomend doing more exercises geared to working out your legs specifically....like biking and maybe even swimming. I also recommend a sauna. But the most helpful trick to loading weight....less sugar and MORE WATER. Try drinking only water for those 3 days and see what a difference it makes.

Actually..they might build muscle. Swimming would be more effective for slimmer thighs.

No, probably the opposite effect because you'll be bulking up on muscle, but they will look more toned.

Die antwört ist NO, It would take a good week and a half

only if you are still alive in that 3 days

use a shake weight between your thighs.

You'll be too tired to care.

it might help but you would have to watch what you eat as well