I have a resident who completed her last triathlon 4 years ago when she was 85. Today at 89 she hopes to complete one again. She has 16 weeks, and already swims and bikes daily. She continues to be active so keeping her on task shouldn’t be a challenge, but older body’s recover longer, how many intense, above normal training days on? How many resting days?
Definitely no problem to be working with older clients, simply have to be more careful and progress smartly. Start them out with what they can do now and keep bumping it up as you would with normal clients.
Take special care in their nutrition, as you might have to take into account chronic illnesses. Osteoporosis and arthritis just to name two.