Trained, seasoned bodies are also tough. When young muscle and mature muscles of the same type and size are compared, the mature muscle is tougher. It may be degraded in some the aspects, such as strength and endurance, but overall it is tough and able to perform under more adverse conditions than a younger muscle might perform.
If you have been around the martial arts for a few years, I am sure you have seen the old guys who can still hold their own and sometimes out fight younger opponents. They seem too know what will happen before it happens, be in the right place at the right time, seem nonchalant in their behavior, and never miss attacking an opening.
When our speed and reaction time degrade, we must make up for the losses by using cunning. Against quick kickers, block so hard that it hurts their legs and knocks them off balance, and stay in so close that their kicks are nullified. Against quick punchers, stay in so close that they are constantly off balance and cannot set themselves for an attack. Do not fight in the “no” zone, that range at which you are in range for being attacked with kicks and quick lunges, but at which you cannot effectively launch an attack. If you stay at a long range, you may be out of range of kick attacks, but you do not have the speed to close the distance in your attacks. If you stay in close, the quicker speed of a younger opponent is partially nullified.