Life starts with almost unlimited and unknown potential. A newborn is a mystery in that he or she might be anyone, might do anything and might even make a difference in the world we live in.
But, the farther along life progresses, the smaller the amount of potential gets. And, in fact, after middle age, losses begin to accrue.
Among those losses, is the loss of the physical traits one needs to ride a bicycle. Vision, hearing, muscle strength, balance and reflexes all decline with age.