My favorite thing to do lately is go far a good swim twice a week. For me that is sufficient and as I get stronger I will add swimming days and maybe start going to the gym. I also try and do stretches in between to help with recovery!
I don't use any app for workout…instead I do some yoga and if the weather is cold out side I do 4 sets of 25 reps inclined and 4 sets of 25 reps of squads. Usually this is enough to generate heat…still if necessary I do 45 secs of elbow plank. Hope this helps