I don't know...I guess every "body" is different, but for me, I've only gotten stronger with age thanks to YOU, Cathe! I'm 48 and yesterday did PLB with 40, 50, and 55 pounds on the barbell with 10 pounds of ankle weights added on to on my waist (including step ups) -my heaviest ever. Because I'm tall (5' 71/2") I have been doing all my step workouts on 10" for years and have never had any joint problems (I know it's a no-no, Cathe, but I love the extra intensity and seem to be doing just fine). The only adjustments I have made over time is to lessen my cardio to 2 or 3 times per week (not because of my age but because of the latest research on cardio vs. weight work) and as a result I am starting to see more definition than ever (I used to do less weight work and more cardio - usually 6 times per week).
Now let me say BY NO MEANS am I bragging here...that would be just plain SILLY...but I just wanted to say that as we get older it IS possible to get stronger! And Cathe, I must say with all sincerity and with utmost gratitude, that I am approaching my 50's healthy and strong thanks to YOU...I use your workouts exclusively and have been for many years...You are truly a goddess and an inspiration to us all...Thank you, thank you, thank you!!!
Robin