Stamina
Endurance is your muscle's ability to do their job over a period of time without tiring.
Endurance is your muscle's ability to do their job over a period of time without tiring.
Endurance is your muscle's ability to do their job over a period of time without tiring.
It is impossible to use your muscles without eventually tiring, otherwise we'd be perpetual motion machines! However, you can increase the endurance of your muscles through cardio and high-repetition weight training.
Muscles
Some sort of aerobic exercise is important. It will improve stamina and ability to work without tiring quickly.
The prefix "un-" can be added to a word without tiring, as it simply negates the meaning of the word without changing its pronunciation or structure.
Cardiac muscle is designed to continually work without tiring
If you mean 'tiring' in the context of: 'that was tiring work' -- Then you have spelt it correctly.Tiring
tiring
The adroit musician could play the guitar for hours without tiring or running out of ideas.