It's a good idea to get your members to track their workouts. Depending on your demographic and how you run your gym and what area of member retention you put the most weight on will likely influence your decision on which workout tracking method you impliment.
4 Great Options
Kilomodo is both easy to use and has a ton of useful metrics
Sugarwod has a good focus on community and super simple to use for members and coaches
Train Heroic is a great balance of simplicity and showing results
Beyond the Whiteboard will give you in-depth analysis of each members progressions.
We recommend you book a demo with all 3 and figure out what works for you best.
This falls inline with our philosophy of choosing the best software for your needs. Currently we have integrations with Sugarwod and Beyond the Whiteboard you can find in our Control Panel under Settings -> Integrations. We are currently working on an integrations with kilo modo, should be out soon. Choice is good :)