I've been through a number of systems for this. I think where I've landed is that this is probably the ideal code-it-yourself opportunity. People often sugges

I've been through a number of systems for this. I think where I've landed is that this is probably the ideal code-it-yourself opportunity. People often suggest todo lists as very easy, but I find those even more complicated than workout tracking. You need to track multiple lists, update existing records, etc. Workout data is pretty "append only". For my workouts, which are fairly simple (and usually involve body weight, a simplifying assumption), a shell script to log the data and a python script to analyze the data works great. When I do 20 pushups, I say "log_exercise pushups 20", with autocomplete and all. It just adds a row to a 3 column file with the epoch timestamp, exercise name, and quantity. With that log, it's very easy to analyze my pushup/chinup/plank/running activity over time. I generally limit my analysis to things like "am I able to do more of xyz than a month ago?" or "how many pushups have I done on average over the past 6 months?" (seeing "avg 2 pushups a day over the past 60 days" gets me embarrassed!). As for web/mobile, I just put my workout in Google Keep on my phone (notes like "10 chinups, 2 miles running, 6 more chinups...") and just enter it in when I get back. For me, this pain is outweighed by having complete control in other areas. I initially thought "oh, this must be a solved problem", so I would look for apps. Over time I realized that a lot of features just weren't necessary for me. I found that graphs of my pushups over time didn't give me additional information. I could see from a table whether or not I was doing a lot or a little. Syncing across devices or seeing it on the go wasn't important. Sharing with my friends wasn't important. Nor was seeing percent increases or goal setting. The biggest benefit was from going from keeping no records to consistently keeping records, and adding a tiny bit of structure.