At this stage in my career I prefer shorter workouts. I’ve been interval training myself since the early 90’s and continue to use that as a base for my cardio exercise (e.g. suicides, ball rolls, plyometric exercises such as line hops…); most of my interval training is based on my preferred ‘work-to-rest ratio’ necessary for my sport. I also no longer try to do heavy lifting but maintain strength with weight training, body weight exercises such as push-ups, suspension training and such. I also do a lot of band and other elastic resistance training. As a tournament tennis player all if this is geared primarily to sports performance.