I don't believe it is. Not for strength training.
I think it's different with aerobic exercise, if you feel tired you will still get through it and it will still benefit (if you are not ill).
If I can't get through the sets in my 2nd exercise of a gym session I will give in, it doesn't happen very often, maybe once or twice a year.
Same with OTB efforts, you need to go supra maximal for the training to be at it's best, if you can't hit that due to tiredness or the onset of illness then leave it alone.
I don't believe it is. Not for strength training.
I think it's different with aerobic exercise, if you feel tired you will still get through it and it will still benefit (if you are not ill).
If I can't get through the sets in my 2nd exercise of a gym session I will give in, it doesn't happen very often, maybe once or twice a year.
Same with OTB efforts, you need to go supra maximal for the training to be at it's best, if you can't hit that due to tiredness or the onset of illness then leave it alone.