A recent article from men’s health inspired me to write this article.

More specifically: they got something completely wrong when it comes to hamstring training.

Here’s what I mean:

The problem here?

Only ONE of these exercises trains the hamstrings: the stiff leg-deadlift.

Squat patterns such as hack squats or front foot elevated split squats (FFESS) do NOT actively train the hamstrings.

Is anyone going to be harmed by this? No, probably not.

However, if you started doing a bunch of hack squats or FFESS as a result of this article to build your hamstrings, you would unfortunately see very little hamstring progress.

So, my aim with this article is to give you an accurate guide to build your best hamstrings yet; including what the hamstrings ACTUALLY do, along with demonstration exercises.

Super quick anatomy of the hamstrings:

There are four muscles that make up the hamstrings:

1. Semitendinosus

2. Semimembranosus

3. Biceps femoris long head

4. Biceps femoris short head

• Some sources will call the biceps femoris one muscle. What happens is that it starts out as two different muscles which merge and insert at the same place.

The first three muscles on this list are biarticular. This is just a fancy word to say they cross two joints: the hip AND the knee.

Conversely, the biceps femoris short head only crosses the knee joint.

This has implications for what movements they are responsible for.

Function of the hamstrings:

As a result of this anatomy, the hamstrings have two different functions:

• Knee flexion

  • This involves your foot being pulled toward your butt, as in a leg curl.

• Hip extension ONLY when the knee angle is fixed and the legs are straight (ish)

  • Hip extension refers to when your knee moves backward and away from the front of your torso

  • A stiff-leg deadlift is a hip extension exercise that involves your knees being fixed. In other words, the knee angle doesn’t change.

  • A squat involves hip extension but also involves knee extension (knee angle is not fixed). So, during a squat the hamstrings lengthen near the hip and shorten near the knee; resulting in no net change in muscle length. With the muscle not shortening in length, this means it is not providing any force and not contributing to the movement.

  • The more straight your knee is during a hip extension, the more the hamstrings contribute.

    • A hip thrust, for example, is a hip extension movement. However, in this, the knees are bent to ~90 degrees. This gives the hamstrings very little leverage to contribute.

    • During a stiff-leg deadlift, the knees are closer to being straight. This makes the hamstrings a prime mover during this exercise.

The absence of active hamstring involvement during squat pattern exercises has been clearly demonstrated in the research:

Remember, though, that three of the hamstring muscles cross the hip and the knee joint.

One of them, the biceps femoris short head, only crosses the knee joint.

As a result, all four hamstring muscles contribute to knee flexion.

However, only the three that cross both joints (semitendinosus, semimebranosus, and biceps femoris long head) contribute to hip extension exercises.

Exercises that train the hamstrings:

Knee flexion

Common knee flexion exercises for the hamstrings include:

• Seated leg curls

• Lying leg curls

• Sliding leg curls such as with a yoga ball or TRX straps

There are advantages and disadvantages to each of these exercises; and I wouldn’t say any are inherently better than another.

For instance, there is research that directly compares seated and lying leg curls. [2]

These exercises are the same except the three hamstring muscles that cross the hip joint are placed in a more stretched position throughout the range of motion.

When volume is equated, seated leg curls grow the three biarticular hamstring muscles more than lying leg curls do.

However, the growth of the biceps femoris short head is about the same between the two exercises.

Furthermore, because the biarticular hamstring muscles are placed in such a shortened position, they become less able to contribute force during lying leg curls.

So, if a person had a particularly week biceps femoris short head, using lying leg curls may be a good idea.

Sliding leg curls are unique in that they require both hip extension and knee flexion. However, the majority of the work done is in knee flexion which is why they were included here.

This exercise trains your hamstrings in a manner that is more similar to what they experience during running. This can make them useful in the final few weeks leading up to a race, whether it is a 5k or a marathon.

In addition, these can make a useful tool in your tool belt if you do not have access to a leg curl machine.

They are more difficult to load than standard leg curls, though, so it is unlikely that they will be as good for building muscle.

Hip extension

Hip extension exercises for the hamstrings include:

• Stiff-leg deadlifts or romanian deadlifts

• 45-degree extensions

• GHD raises

These exercises vary in regard to where in the range of motion your hamstrings feel most of the tension.

As a rule of thumb, there will always be the most tension on your hamstrings when your torso is parallel to the ground.

In a deadlift, this is when your hip is at a 90 degree angle.

Ia a 45-degree extension, this is when your hip is at a 135 degree angle.

In a GHD raise, this is when your hip is at a 180 angle (ie your hips are straight).

Deadlifts put most of the tension on your hamstrings in their stretched position.

GHD raises put most of the tension on your hamstrings when they are in a shortened position.

45-degree extensions fall in the middle of this.

As another rule of thumb, the more of a stretched position a muscle is in when it is trained, the more advantageous it is for growth.

This has been tested across a number of different muscles in a number of different ways. [2,3,4,5,6,7]

Based on this, deadlift variations are arguably your best bet for training the hip extension function of the hamstrings.

However, these papers also show a small degree of regional hypertrophy. This means that different parts of the muscle might grow more or less depending on if the muscle is in a shortened or stretched position while it is trained.

So, exercises like the 45-degree extension or GHD raise shouldn’t be counted out; but they should not be seen as good as deadlifts.