My personal opuinion (and how I workout):
- any repetitive exercise is dangerous without warming up - particularly if you're doing strength training/resistance.
What do I do?
I warm up. Rotate all my joints as well as I can - taking special care to rotate my "stress" joints - knee, ankle, wrist, shoulder, lower back and neck.
Then I walk on the treadmill.
Then jog/run. I usually do a combination -- say 6 minute walk, followed by a 6 minute jog/run. Repeat two more times (i.e. 6 walk + 6 run + 6 walk + 6 run). [You may start out lower or higher, depending on your individual needs and goals].
By the time I'm done, I've run/walked a good 30-40 minutes. Now I do weights. I concentrate on one part of my body twice a week:
Monday and Thursday - Chest and abs
Tuesday and Friday - Biceps and triceps
Wednesday and Saturday - Shoulders
It's not a professional gym - it's just my treadmill and dumbell kit in my absement ... but I've been at it for 2 solid months and I can see definite, dramatic results
For example, my suits and shirts have grown tighter around the shoulders and chest
PS: You should check out our Healthy Living forum
Hope this helped