I think by weaker you mean that they cannot lift things or move things as easily as a young person. The ageing process is a very complicated process and during ageing many things happen. Muscles begin to get smaller. The muscle tissue changes and muscles become slower. That is why sprinters like 100, 200 metre runners are below 30 years of age while runners who run very long distances and I mean from London to Brighton or longer are older up to 50 years and beyond. Not only does the muscle tissue shrink but the muscles get more fatty and fat is useless for movement. This happens to all muscles. Is there any way this process can be stopped? No! We are all going to die. Is there any way this process can be slowed down so that we can remain fit until we are very old? At last a Yes! The answer is so simple you will think I am kidding you, but I am very serious. Everyone must exercise as much as they can. While exercise will not make much difference when young the differences it makes in older people is like a “wonder” drug. Exercise will prevent a lot of the diseases that older people get. Women in particular must exercise in order to stop their bones wasting away. However it is very difficult to get people to exercise. Do you exercise? If not why not? My experience is the reasons are not very convincing. I exclude people who have handicaps.