The Activity Rings on your Apple Watch don’t provide a complete picture of your fitness. There is one important ring missing: Strength. The Rock didn’t get ripped just by standing up once an hour. And both the Exercise and Move rings essentially measure the same thing: cardio.

As any fitness expert will tell you, an effective workout program should combine cardio with strength training. Here’s why strength is currently Apple Watch’s weakness, and how you can use third-party apps to make sure it isn’t yours as well.

You have a gym membership, but you’ve talked yourself out of going. You paid for a personal trainer and found reasons to cancel.

Maybe fitness can be achieved through your smartphone or smartwatch, but the excuse that now grinds the revolution to a halt is too many apps from which to choose.

Freeletics, a workout app that made its U.S. debut earlier this month, wants to make this an easy choice. First, it invites you to join more than 7 million other users, a community, the company says, grows by more than 6,000 users a week.