In my years of experience in coaching,track athletes, cross country runner and road runners I have found one common problem, faulty running mechanics causing the foot strike to be on the heel instead of the correct mid foot strike. Running with your feet instead of on them causing over striding leading to heel strike with a straight leg with the knee locked of semi locked. This prevents the natural shock absorption of landing on the mid foot with the knee unlocked and the body centre of mass over the foot strike.
The current generation of over engineered, over padded, elevated heel and over priced running shoes cause people to land with a heel strike. On my Spark page is a picture in the gallery of two runners side by side one running with a proper stride and foot strike and the other running to injury.
It is called WORK-ing out for a reason.
I said getting fit was simple, I did not say it was easy.
Cardio burns calories, strength work burns fat.
Eat well to lose weight, exercise to get fit
You can not build a six pack using twelve packs
Often when we seek a magic bullet for fitness we end up shooting ourselves in the foot.
"I think calories are little germs in food that all moms are afraid of" Dennis the Menace