Nordic hamstring curls have been popularised recently thanks to some very positive research studies and an endless stream of social media posts. Social media proclaims “70% reduction in hamstrings injuries” and “a mandatory exercise for every rehab & prevention program.” But do Nordics deserve their reputation?
What is a Nordic hamstring curl?
As a bit of background, Nordic hamstrings curls are an eccentric exercise (muscle lengthening under tension). Here’s an example of how to do a Nordic hamstring curl.
What is the research on Nordic hamstring curls?
In 2011, a researcher by the name of Petersen, along with a research team, published a great study looking at the effect of Nordic hamstring curls on 942 football (soccer) players. They found a huge reduction in new and recurrent hamstrings injuries.
Other papers have been published since 2011 with similar findings – one paper by van der Horst (and friends) in 2014 found a 70% reduction in hamstring strains! You’ll often see the 70% figure quoted on a social media post declaring with smug reassurance, Nordic hamstring exercises are both magic and mandatory. It’s simple and ridiculously effective. Almost too good to be true…
Awesome right? Just add Nordic hamstring curls and stop injuries before they happen.
If only it was that simple…
Are Nordic hamstring curls the best option?
As always, social media doesn’t tell the full story, and the devil is in the detail. These studies compared regular training + Nordic curls to just regular training, that is on-field training without strength training.
As you may expect stronger athletes were more resilient to injury. Simply adding strength training improved muscle function very quickly, with one study finding significant gains after just four weeks.
But what we’re yet to see is how Nordic hamstring exercises compare to other strength exercises, such as a single leg deadlift, for injury prevention.
We’ve had studies compare Nordic curls and deadlifts for muscle recruitment patterns. They’ve compared Nordic hamstring curls to improvements from sprint training. And in almost all comparisons, Nordic eccentric curls haven’t been superior for performance or strength gains. They’re an effective strength exercise, but they’re one of many effective strength exercises.
What we can’t recommend with any great certainty is the effect of Nordic eccentric curls over other exercise options. The data just isn’t there to support that conclusion.
A simple analogy
A simple analogy to real world examples would be putting petrol in a car. We test a car without petrol compared to a car filled with Caltex-brand petrol. Not surprisingly, the petrol-filled car goes further.
We can safely conclude that petrol is great at making cars go further. But to claim that it proves that Caltex is better than Shell petrol just wouldn’t be right.