Gotten involved in cycling again after like a 25 year break(I'm 63). I bought a Trek Hybrid and it's been ok. I'm riding about 50 miles a week right now. But I don't really see much improvement in speed, ability to climb, etc. Back in the day, if I was riding regularly I'd see real improvement in my ability to climb and go longer distances. But I don't really see much/any improvement now. Is it just that at my age, muscles don't build easily? Any suggestions about how to proceed? Thanks!