There are a variety of activities that promote good balance. Joining a yoga, Pilates, or tai chi class can help you improve balance.   Tai chi is a form of movement training that promotes coordination, strength, and balance. Many fitness and community centers offer tai chi classes. See what's available in your area by browsing the yellow pages, checking online, and looking for ads in the local paper. If there aren't classes offered in your area, you can buy or rent DVDs or find videos on YouTube that teach basic tai chi poses.  Yoga and Pilates are both forms of exercises that promote strengthening core muscles by moving between a variety of poses. Yoga has the added benefit of teaching mindfulness and meditation. In addition to improving balance, yoga could reduce overall stress. Like tai chi, fitness and community centers may offer yoga and Pilates classes. You can also buy or rent DVDs or find instructional videos online. While you're doing day-to-day activities, practice balancing. Try to stand on one foot while brushing your teeth, waiting for a bus or train, doing your makeup or brushing your hair, and other daily activities. Your balance will improve greatly if you strengthen your buttocks, hamstrings, and quadriceps. Aerobic activities, like running and jogging can help. You can also engage in low impact weight training, like lifting weights at home or doing push ups, sit ups, squats, and other easy exercises to do without heavy equipment. Try incorporating a medicine ball into your workouts to build core strength.

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Write a summary of the previous text in Vietnamese:
Tham gia một lớp học. Luyện tập giữ thăng bằng khi rảnh rỗi. Trở nên mạnh mẽ hơn.