How many times should i cross train and run in a week?

? goal: Depends on your goal. If triathlon training, then depends on distance of tri and how many months of training left, and current condition. If simply to achieve / maintain good condition / health, then another story. If training 6 days per week , then split it, and see how it goes. Adjust from there depending on your goals. Also depends on what x-training you do. Good Luck.

Running.: The surgeon general informs us to run on most days of the week, so perhaps five or six days per week would be great. Not seven days - give yourself a chance to rest. Start running 25 minutes per session, as you need at least 20 minutes of sustained heart rate elevation for the cardiovascular benefit, and build up from there as your tolerance for exercise improves.