making progress

So I have to say that I was delighted this week when I woke up and went for a run. I try to do various types of cardio. I have a stationary bike, a heavy bag and a speed bag. Cardio is about raising the heart rate and working up a good sweat. I have even done some of the thirty minute workouts that you can see for free on fit tv. But I have never really been able to run for an extended period of time. But this week I have felt the urge to try and run. So monday morning I woke up and took a run. I soon noticed that it was not as uncomfortable as I remember it being. I should say that I did invest in some good running shoes but , my knees were not killing me and my lower back did not hurt. Im going to throw running in the mix, along with swimming walking biking and boxing. Personally I think it is important to change workouts as to not get bored

Squats
Leg Extentsions
Calf raises
Bent over Rows
Bent over Flyes
Thirty Minutes Heavy bag