We do get stronger as we get older until about 25-35yrs, where we reach our greatest potential to be strongest. After this there is a very gradual reduction in muscle mass through hormonal changes as we age. The reason adults are still stronger than children is because the process of muscle loss with aging is a lot slower than the process of muscle building until we are mid 30’s. Further, we keep using our muscles throughout life and all the time we are using them effectively they do not reduce so much. Older people have been shown to get excellent strength gains when doing resistance training.