If you are going to do aerobic activity though please do it at the right speed for fat loss, in other words, keep your intensity to the level that you would be able to carry on a conversation comfortably while performing the activity. This will keep you within the ideal fat burning range. If you go too hard, you start to burn carbs rather than fat. If you decide to weight train as well, that's great. In general, remember to warm up well, work on flexibility and do not make the mistake of thinking that high rep and low weight lifts result in definition.
Definition is more related to diet.
Too often people perform these baby lifts for minutes thinking they are doing great things for their muscles. And no, doing this will not make you look like a gorilla. The truth is that most are useless. And many of them are just plain stupid. Excellent for nighttime GH release.