Your Quadricep to Hamstring Ratio: Why It May Be the Key to Injury Prevention
by Melinda Burris

This article explains the hamstring to quadriceps (H/Q) ratio, why it is important in the prevention of injuries, and how you can measure your ratio to see if you have a good percentage. Exercise instructions are provided to assist you if you find that your hamstrings and quads need strengthening.

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Defining the H/Q Ratio

So, what exactly is the hamstring to quadriceps ratio? The H/Q ratio is a simple means of quantifying the relation of strength between your hamstrings and your quads. As an example of a motion that exemplifies this, consider the action of kicking a football. When you perform the kicking action and strike the football, the hamstring muscles must lengthen under load (also known as an eccentric muscle action). At the same time, to complete this move, your quadriceps muscles must shorten (also known as concentric muscle action).¹

This example illustrates the reciprocal relationship that exists between hamstrings and quadriceps. So, why is the H/Q ratio important? As we will explore in more depth, an unhealthy H/Q ratio can interfere with the proper function of the knee joints putting an individual at increased risk of injury.¹

How to Measure Your H/Q Ratio

Professionals in training and rehabilitation centers commonly use an expensive instrument known as an isokinetic dynamometer to calculate H/Q ratio.  This option isn’t readily available to most people. Thankfully, there is a simple way to gauge your hamstring/quad strength by completing a simple exercise on workout machines commonly found in just about any gym or training center.¹

How? Using a leg extension or seated curl machine, do a 1 rep maximum (1RM) test. This will determine the maximum weight you can lift in a fluid motion while maintaining control and good technique as you complete the full range of movement. While you won’t get the full range of data an isokinetic dynamometer provides, you will be able to identify areas that need strengthening.¹

What H/Q Ratio is Optimal and Why Does It Matter?

So, what is considered a good H/Q ratio to protect the health of the knee? Research studies indicate “that a 50-80% (ratio of 0.5-0.8) is acceptable, but greater than 60% is desirable. To help explain, this is the percentage of strength of the hamstring muscles in comparison to the strength of the quadriceps. So, for example, if this ratio was 80%, the hamstrings would be able to lift a maximum of 80kg in comparison to a 100kg quadriceps maximum.”¹

Research demonstrates that ideally, your H/Q ratio should be as close to 100% as possible, meaning your hamstrings and quads have the same level of strength throughout the full range of movement. Having this high and equal amount of strength in both muscle groups is an important factor in lessening the chance of incurring a hamstring strain and/or the partial dislocation of a knee in people who have suffered an anterior cruciate ligament (ACL) injury in the past.¹

Injuries to Which Quadriceps and Hamstrings are Commonly Susceptible

Dr. Dan Davis explains, “Cramps are more common than pulls or strains and are more common for hamstrings than for quads. As with most muscle cramps, they usually result from inadequate hydration. So, drink sufficient fluids and remember that water and calcium are both important to have in your body.”² Muscle strains or pulls or also fairly common. Dr. Davis goes on to detail certain factors that make you more susceptible to these types of injury:

1. Age – As we get older, our risk of suffering muscle pulls increases.²
2. Previous injury – According to Davis, once a muscle has suffered an injury the likelihood of future damage “greatly increases.”²
3. Lack of flexibility – This is “due mostly to failure to properly stretch the muscles beforehand.”² That is why proper stretching and warm-up before undertaking any physical activity is so important.

Dr. Davis is quick to emphasize that “The key point to remember is that quads and hamstrings are sets of muscles, not individual muscles. Consequently, one move or series of moves does not stretch the entire group. It takes three separate sets of stretches for each muscle group. If you only do one of them, which is what most people do, you have a 66% chance of incurring a hamstring or quad pull.”²

Exercises That Will Strengthen the Quads and Hamstrings:

• Bulgarian Split Squat³

1. You will need a step that is approximately knee height to complete this exercise. Place the step one full stride length away from you.
2. Begin by facing away from the step, then rest your right foot with the laces facing down on the step.
3. Bend the left knee making sure it lines up over your left ankle. Continue this bending motion until your right knee is almost touching the floor.
4. Push yourself back up through the heel of your left foot until your left leg is straightened.
5. Complete 8-12 reps, then switch legs. Complete three sets.

• Reverse Lunge³

1. Stand, placing your feet hip-width apart, while holding a 5–10-pound dumbbell in each hand.
2. With your right foot, take one step backward, then lower your body until your right knee is just a few inches from the ground.
3. Return to starting position.
4. Alternate legs, completing three sets of 8-12 reps per leg.
5. You can change this exercise up by using an aerobic step (approximately six inches high).

• Stability Ball Leg Curls³

1. Lie on your back, arms at your sides, with your legs out straight and your heels resting on a stability ball.
2. Lift your hips off the floor, then contract your hamstrings and pull the ball toward your rear end using your heels.
3. Extend your legs to repeat one rep. *Your hips should remain elevated throughout the entire exercise.
4. Complete three sets of 8-12 reps.

References:

1. Langford, T. (2024). A Balanced Approach to Leg Strength.
2. Davis, D. (12 October 2015). Leg Maintenance: Protecting your Quads and Hamstrings.
3. McDowell, D. (7 December 2011). 3 Exercises for Your Quads and Hamstrings.

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