When men curl too much weight (and most do), they end up flexing their wrists to assist with the movement, says sports coach Alwyn Cosgrove. This in turn places tremendous stress on your forearms, causing the muscles to contract under loads that are way too heavy. “It creates discomfort and severely limits your performance,” he says.
The prescription? Don’t do any more curls until you can perform at least five pull-ups. These will strengthen your bicep muscles by forcing them to handle heavier loads than you can curl. And while you’re pumping your biceps by doing pull-ups, you can still do hammer curls. This variation of the standard dumbbell curl takes the stress off your wrists because your palms face each other. Hammer curls strengthen the brachioradialis, which is often the weakest muscle in your arm.
Keep in mind, however, that hammer curls target less arm muscle overall, so after you’ve built up your forearms, continue with barbell or dumbbell curls.