Hamstring exercises are the Shakeweights and Slapchops of the late 2000s—wildly popular but not exactly getting the job done.

Athletes today have complex GPS systems tracking every step, load management logging every squat, and data monitoring every minute detail. But despite all the tech, hamstring injuries are only increasing. If these exercises and technology worked, we’d see fewer athletes sidelined. Yet here we are, year after year, watching them drop like flies. How do we prevent this preventable anguish?

The problem is that all this tracking and management looks scientific, and some of it is, but it’s not actually solving the problem. (In fact, it’s fueling it.) And these popular exercises are supposed to prevent injuries, but they don’t. And when something should work but doesn’t? We must look deeper. Time to find what we’re missing.

Here's a thought: What if the answer is where we least want to look? Or where no one is looking? What if it’s so obvious that it is hard to see?

Every time I bring up hamstring injuries, someone chimes in with, “Well, injuries are complex…” Yeah, I’ve heard that so many times it’s become a thought-terminating cliché. It’s true, and I’ve said it too, but complex or not, these injuries still need solving. Thankfully, even complex problems break down into parts.

Let’s examine the knee. Most people think of it as a simple hinge joint, bending and straightening in isolation. But the knee does more than that—it rotates as it bends, at least it should. I don’t use that word lightly, “should.” I’m a fan of abundant movement solutions, except when our anatomy clearly says, “Do this.” And for the knee, rotation is non-negotiable.

If we’re treating the knee as a basic hinge, we’re already off track. That’s where conventional hamstring exercises miss the mark: they ignore what’s happening below the surface.

Evolution crafted our anatomy, and she left us with clues about how we’re meant to move:

The semimembranosus is the biggest hamstring. Clue: big muscles are built to take on big loads.
The pes anserine—a group of four tendons on the inside of your knee—clearly have one job: shin internal rotation during knee flexion. (See image below.) Clue: shin internal rotation is part of the knee’s natural mechanics.
The peroneals use the lateral malleolus as a pulley to internally rotate the fibula during dorsiflexion. Clue: again, shin internal rotation matters.
Humans have more dorsiflexion with eversion than inversion. Eversion and tibial internal rotation are paired together. Clue: there’s a specific pattern repeating itself here.

Put these together, and you get a clear picture of how the knee should bend: with internal rotation of the shin. Whether it’s knee flexion during the swing phase of sprinting or the triple flexion of a single leg squat, shin rotation should happen naturally.

But let’s be clear: shin internal rotation does not mean the foot turns with it. The shin rotates independently, below the knee but above the talus. If the foot points forward or in the direction you’re moving, you’re good. The more the knee bends, the more the shin should internally rotate.

When we ignore lower-leg internal rotation, and athletes wind up with lower-leg external rotation, we end up overloading the hamstring that tears most often: the biceps femoris. And that’s when the problems start.

*(In blue, you see the pes anserine of a right knee.)*

When someone injures their hamstring, it’s often the long head of the biceps femoris taking the hit. We tend to focus on the muscle's obvious roles in knee flexion and hip extension, but it's also responsible for fibular external rotation and hip abduction. So, where else are athletes training these lesser-known movements? In the majority of popular weight room movements:

Squats: but always with your knees and feet turned out. (The feet are often turned out more than the knees as a substitute for poor dorsiflexion.)
Deadlifts: knees and feet out.
Lunges: knees out.
Sumo deadlifts: abduction and external rotation of the legs.
Jumps: knees out—always.

These go-to moves are hammering the biceps femoris, while the bigger muscles that should be pulling weight are left underworked. It's like giving all the work to the smallest and weakest guy on the team and then acting surprised when he collapses.

Maybe we’ve been complicit in these injuries, clinging to reductionist cues instead of facing a more complex truth: the body is way too intricate to be reduced down to one line of instruction.

Now, I’m not saying knees and feet need to turn inward. But the most popular weight room movements keep biasing the biceps femoris (short head and long head)—the smallest muscles on the hamstring team. It's time to call up the bigger teammates with different movements and, for god's sake, some better cues.

Some of those different movements, categorically, should be hip adduction. Instances where the pelvis shifts over the knee and the ankle everts. Again, this isn’t the knee moving toward the midline, but the midline moving over the knee.

*(Note the strap letting him adduct his hip and evert his ankle. Later, you’ll see that you can also do this against a smooth wall.)*

Again, one of the most common “compensations” in all humans is shin external rotation during knee flexion. This pattern shortens the biceps femoris, putting a straining tax on a muscle that never evolved to pay it. That is not how the knee evolved to bend.

Check out this video as I assess tibial external rotation during walking.

*(Note the differences between legs during swing phase. I bet you can guess which knee and ankle she had problems with.)*

*(Same girl from the treadmill photos above showing that her tibia likes to externally rotate in squats as well—it was almost all movements.)*

Recapping The Vital Points So Far:

Bicep fem. gets hurt a lot.
People train bicep femoris a lot, based on common training movements. Too much. They have no idea.
Bicep fem. can’t do everything—doesn’t have the capacity. It small.
Coaches and practitioners rarely look at tibial rotation.
Semimembranosis: big, strong muscle. Gets ignored.
Pes anserine, a grouping of tendons, yearns to create knee flexion and tibial internal rotation. There’s no structure like this on the outside of the knee, no structures indicating knee flexion and tibial external rotation are the right way to bend a knee.
I haven’t met anyone who trains the peroneals to create shin IR. Yet, it’s clearly an essential action.
Zero, and I mean Z E R O, animals bend their knees with shin external rotation. We’re not that exceptional. (If you have found one such critter, show me this exception.)

So what does all this mean? It means our hamstring training isn’t just off—it’s backward. Focusing on the wrong cues and ignoring the knee’s natural movement pattern sets up the biceps femoris for a beating. But fixing this isn’t as simple as switching up reps.

In Part 2, you’ll learn another layer of the problem: the pelvis. And we’ll talk about training options.