Ways to include sports activities in the workplace:
Create a No-Internal-Phone Day
Although office managers cannot do much about the need for workers to use their computers, they can stop them from using other technologies that are keeping them strapped to their chairs. Employers can choose one day a week to stop workers relying on their phones to talk to other staff in nearby departments. This would have to be implemented within reason, but it would mean workers have to get up and go and speak with other staff at their desks.
Step Counter Challenges
One easy and fun way to get the whole office involved and more active is to introduce step counter challenges. They are universal now, with so many offices providing this in-house challenge between workers to find out who is the most active. You could even offer a prize for the winner such as an extended lunch break or extra holiday.