To Nordic or not to Nordic?
The Nordic hamstring exercise has received much attention over recent years. It is popular with a lot of practitioners and not so popular with others.
I have published research and blogged previously about the NHE. Please take a look a what we found.
So, what is it?
The NHE is a knee extension/flexion exercise performed while kneeling. For definition, the Nordic hamstring curl is a combination of extension and flexion but this is reserved for the super-strong among us. Those with hamstrings of steel! I prefer to use an eccentric extension option, and I'll come on to why later on.
A good unassisted Nordic lower looks like this:
Why do we include the exercise in our programmes?
Well, firstly the NHE isn't for everyone. However, it is important for athletes that run at high-speeds. This includes team sport athletes such as football and hockey players as well as straight line runners such as, 100m/200m sprinters.
This is because:
The NHE trains the hamstrings to tolerate high muscle forces, particularly eccentric forces - and elicits higher neuromuscular responses than all other conventional exercises. By training the hamstrings to have a higher eccentric capacity, muscle forces experienced during sprinting become relatively lower.
Training the exercise also increases the fascicle length of the hamstring muscles. Meaning that higher muscle forces can be tolerated throughout a greater range of motion. Enter the concept of 'strength at length'.
Because of the high load placed on the hamstrings other tissues such as tendons adapt to become structurally superior. Hopefully mitigating the risk and severity of hamstring injuries.
Finally, training the hamstrings to produce higher forces (which can achieved by training eccentrically) will enhance the overall propulsion and mechanics of running at speed.
Now, the exercise doesn't work so well when athletes don't go through a full range of knee extension. The reason they can't do this is that the muscle forces required are simply too much. This is entirely normal in strength training. For example, we don't expect athletes to squat with 100kg the first time they pick up a bar. We find a tolerable load and progress them sensibly.
This is why it is important to start using the Nordic hamstring exercise with assistance.
Assistance can be used in a few ways. Some use bands, which are transportable and accessible but vary the assistance given at different ranges of the movement. Using cable machines offers a quantifiable load by which the level of assistance can be selected appropriately.
Take a look at me researching the effects of assisting the NHE (pilot data) in the video below with my good friend and colleague, Dhani Pattison-Hughes.
My research found:
Eccentric knee flexor strength was significantly lower when assisting the NHE with loads that equated to 5, 10, 15 and 20% bodyweight.
Assisting the exercise made it feel significantly easier to perform
Assistance did not change the neuromuscular demand on the hamstrings. Suggesting that we can reduce load and still challenge the neuromuscular capabilities of the hamstrings.
This is important because... athletes that sprint need to tolerate high muscle forces in the hamstrings. In particular, at the end range of motion - strength at length. If we set our athletes up to fail by placing them under loads they are incapable of matching, we do not achieve strength at length.
At Impulse when training the nordic we start small and work up. It is important to gradually reduce assistance until the athlete can perform three good reps at bodyweight.
When the athlete can do this they will be creating adaptations in the hamstrings far greater than they ever could have been at smaller ranges of motion. Eccentric muscle strength will increase. The hamstring structure will be improved and healthier. The athlete will also have a better chance of moving faster!
When Nordics at bodyweight become easy, add weight. Hold a 5kg plate to start with and keep working up!
I'd like to mention here the people that helped with my research and I am always grateful for their input. Dr Daniel Cleather, Dr Giuseppe Cimadoro and Dr Ryan Mahaffey.
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