Effective, because these workouts have been tested through history, and their effectiveness on the human body has been both documented and researched, as well as passed down by word of mouth from those around us.
Simple, eight-duanjin, (simplified) taijiquan, focusing on the movement, a few movements to repeat, simple to learn, easy to start. Zero foundation can follow the practice, follow the practice a few times to get the hang of it.
Free, thanks to the country's free promotion of eight-duanjin, simplified taijiquan, and in the university to promote 24 simplified taijiquan, as long as you want to learn easy to get. And this activity, do not need professional venues, equipment, anytime, anywhere you can practice, no pre-investment costs, zero threshold entry.
Sports that can be effective, simple and free to compete with Baduanjin and taijiquan are square dancing (requiring speakers), walking (monotonous) and running (exhausting). These are also popular forms of exercise.
In short, not subject to venue, equipment, group constraints, free, simple, effective, but also not bitter and not tired.