The hamstrings are muscles that run from the pelvis down the back of the legs to the knees, and they are important muscles for stability and strength during physical activity. Strengthening hamstrings starts with developing a workout routine that will directly benefit those muscles as well as supporting muscles, tendons, and ligaments. As with any workout routine, a proper warm-up is necessary to prevent injuries, and the person doing the workout should be careful not exceed his or her fitness level too quickly. This will also help prevent injuries, which can stall progress or weaken the muscles altogether.
If the person is new to the workout intended for strengthening hamstrings, it is wise to start small and build up from there. Starting with less weight allows the exerciser to gauge his or her fitness level, and it prepares the muscles for the strenuous nature of the workouts. Starting with too much weight or too many repetitions can lead to injury or excess soreness, which can in turn lead to setbacks in the strength training program. Regardless of how strenuous a workout tends to be, the person should always start and end with light stretching that will help prevent injuries and soreness.
Many professional trainers will recommend lunges as the core exercise for strengthening hamstrings. Lunges require no specialty equipment, unless the user decides to make the exercise more difficult by using dumbbells or weight plates. Performing a lunge should start with the person standing up straight with his or her feet about hip-width apart. The person will then step forward with one foot and plant it solidly, leaving the other foot in the original position. With his or her back straight, the exerciser will lower the upper body until the front leg is bent at about a 90 degree angle. This position will be held momentarily, then the person will return to the starting position. This motion will be repeated several times with each leg.
If the point of strengthening hamstrings is to improve one's performance at a particular sport, the person may want to consider the different types of exercises available. Some exercises will improve "explosiveness," which will be useful for runners and athletes who participate in sports with a fair amount of running. Strength exercises intended to build bulk in the muscle will be more useful for weight lifters, athletes who will routinely lift heavy objects, endurance athletes, and more. Isometric exercises will be effective for explosiveness, while strength training with weights will be better for other athletes.