Highly effective method of load progressive stretching for hamstrings and the rest of your posterior chain. 3 sets for 10 reps + hold for 10 sec on your last rep. Stay active in your legs. Keep your body upright; don’t round your spine. Use a weight that is manageable for you and also gives you some feedback. Too light or heavy is no bueno. Hold the last rep at your end range of motion. Remember to still remain active in your legs!