2. Weight Bearing Exercise Is So-So

Weight bearing exercise is generally carried out at the gym on exercise machines, or using free weight (dumbbells, etc).

The trouble with most weight-bearing exercise is that it moves the muscles in a set, unnatural way repeatedly. This leads to unnaturally bloated muscles which have been 'built by rote' - not in a natural way. Natural muscle building combines brain, lungs and muscles. Gym-based, artificially built muscles are more prone to injury, and less strong and flexible than muscles trained naturally - and interval-trained muscles are tops!

Most importantly, interval training avoids the joint, muscle and tendon injuries which weight lifting often lead to.

(Dr Al Sears, Rediscover Your Native Fitness, Page 66)