pick up two 3 lb weights and hold tem out in front of you with your arms straight and perpendicular to the ground. You'll reach muscle failure pretty quick
And be much less likely to injure yourself than trying to do three sets of military presses with heavy weights. It just requires a different type of exercise, I wouldn't want to do 300 curls with light weights either. I can reach muscle fatigue with some seemingly simple yoga exercises very quickly.
A karate monitor told me his secret. He started with heavy and reduced the weight until he ended with just the bar. I tried it and in just four series with few repetitions the muscle feels like it's lifting the whole weight, not just the bar.
I don't think this works any better than the reverse (starting lighter, ending with more weight/fewer reps), or a few sets of constant weight (after warmup). It's a well known variation.
It seems feasible it could work better. If you lift an X lb weight until you cannot lift it anymore, and then drop to X/2 lbs, you can lift again, and can drive your muscles even further into exhaustion.
We used this method in high school (called it burnout then) and it never ceased to fail that a pretty girl would walk in when you got down to the bar and could barely lift it!
