Essential Strength Training Skills /by DK Publishing. Perfect for all ages and skill levels, the Essential Skills series is at-a-glance reference packed with instant-access, easy-to-understand tips to help you improve your game, your technique, and your creativity. Whether you ve been weight training for years or are newly interested in getting toned, Essential Strength Training Skills offers advice ideal for both beginners and seasoned veterans, providing clear and accessible exercise tips that can help anyone get into peak physical condition.