“When I really want to get medieval, I pull out the SpeedChain – which really does look like something out of the Middle Ages. It’s a golf shaft with a 20 or 30-foot-long chain of heavy links attached to the bottom. You get on the grass and sling the chain back and forth as if you were cracking a whip. It’s a brutal exercise and five minutes of it once a week is enough to really develop strength and speed in your core muscles.”

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