The Ratio of Hamstring Strength

The hamstring muscles in the lower body are often overlooked when working out in the weight room, but it's important that they possess an adequate amount of strength in comparison with the quadriceps in order to prevent injury. Track participants and other athletes required to sprint in their sport are often the most susceptible to hamstring weakness injury. You can test your hamstring to quadriceps ratio and participate in strength training to improve your ratio as necessary.

Hamstring

The hamstring muscle group consists of three muscles, including the simitendinosus, semimembranosus and the biceps femoris. The muscle group runs down the back of your thigh, originating up at your pelvis and inserting down at tibia and fibula, or your lower leg. Together, they are involved in knee flexion and hip extension.

Hamstring to Quadriceps Strength Ratio

The quadriceps muscle group runs along the front of the upper thigh and consists of four muscles, including the vastus intermedius, vastus lateralis, vastus medialis and rectus femoris. The quariceps are responsible for extending the knee and flexing the hip, which is movement opposite to that of the hamstrings. The strength ratio of hamstrings to quadriceps should be at least 60 percent but ideally 75 percent.

Significance

The hamstrings are highly susceptible to injury, typically caused by a pulled hamstring, or muscle strain. They typically occur when a person is sprinting and are commonly caused by a lack of hamstring strength to quadriceps strength ratio. A lack of hamstring strength can also put you at an increased risk of injury to the ACL, or anterior cruciate ligament, which is a ligament that facilitates with knee stability.

Testing

To test whether your hamstrings are at the proper strength ratio compared to quadriceps, complete one repetition maximum tests for both the leg curl and leg extension exercises. Divide your leg curl score by your leg extension curl to find the ratio. For example, if your leg extension maximum is 85 lbs. and your leg curl maximum is 50 lbs., your strength ratio would be found by dividing 50 by 85, or 0.59. This can also be expressed as 59 percent.

Strengthening

Exercises effective at developing the strength of the hamstring muscle group include deadlifts, exercise ball hamstring and kneeling hamstring curls. To significantly improve strength, complete workout sessions two to three days per week. Each exercise should be completed at a volume of two to three sets of six to 12 repetitions.