I like to get as much done in as little time as possible. So, I typically combine both cardio and strength training to make the best use of time. It keeps your heart rate up and interval work really burns fat!
I like to do challenging exercises that involves multiple muscle groups. I think it takes your mind off the pain when you have to think about what you are doing. It’s fun to challenge your body and then feel accomplished when you are done!
Last, I like to do exercises that strengthen your core without lying on the mat for thirty minutes. It is not an effective use of time. Most of the core strengthening from my workouts will be from doing full body exercises that involves your core. Balance exercises are also a good way to improve core strength.
The important thing when exercising is challenging yourself. It is so much harder to see results when you are just going through the motions. If you keep your body guessing and keep challenging yourself, you will see results.