Perhaps you’ve seen Knees Over Toes Guy discussing how incredible the benefits of Nordic curls are when it comes to developing lower body speed and explosive power…
Patrick also mentions that the Nordic curl is the single best exercise for horizontal jump development, but does this translate into vertical jump excellence?
Although not directly responsible for increasing total force output when jumping, the Nordic curl is still a very effective way to increase your vertical jump.
By increasing knee flexor strength and durability, we’re able to facilitate greater power generation through the knee extensors.
In this article I’m going to summarize all of the current research linking Nordic curls to vertical jump performance, and then I’m going to explain exactly why you absolutely must be doing Nordics regularly if you want to jump higher.
What Does The Science Say?
Unfortunately there’s not a crazy amount of research on the subject just yet, but there is a few studies which involved Nordic curls and the measurement of vertical jump progress…
Let’s start with the oldest study and work our way forwards.
2005 Study: Nordics Improved Vertical Jump
In 2005 a group of 9 athletes were prescribed Nordics twice a week for a period of 4 weeks.
The study found a significant increase in vertical jump height as well as favorable changes to the peak torque measurements for both the hamstrings and quads.
Although this study used a small sample size and a relatively short training period, researchers concluded that Nordic curls are likely to increase vertical jump while reducing the likelihood of hamstring injuries in athletes.1https://www.researchgate.net/publication/228344677_The_effects_of_eccentric_hamstring_strength_training_on_dynamic_jumping_performance_and_isokinetic_strength_parameters_A_pilot_study_on_the_implications_for_the_prevention_of_hamstring_injuries
It’s not much, but it’s a start!
2011 Study: Nordics Massively Improve Vertical Jump In Rugby Players
In a more recent study on the effect of Nordics on lower body explosiveness in rugby players, they also found some pretty favorable results.
Twenty-four players were split into two groups: one group trained as normal for 10 weeks, whereas the other group did a Nordic curl protocol as well for 10 weeks.
…There was also a significant increase in vertical jump height for the Nordic group (pre=31.22 ± 4.8 cm, post=35.93 ± 4.5 cm).2https://www.researchgate.net/publication/282256324_Does_the_eccentric_Nordic_Hamstring_exercise_have_an_effect_on_isokinetic_muscle_strength_imbalance_and_dynamic_jumping_performance_in_female_rugby_union_players
This is a very significant increase and the study also found that Nordics were a great choice as a prophylactic/rehab exercise for the hamstrings.
2017 Study: Nordics Make Soccer Players Sprint Faster & Jump Higher
Moving on to a far more recent study, Nordics were prescribed to a group of 19 elite soccer players, half of which did Nordics in addition to their normal workouts and the other half didn’t.
Sprint performance as well as vertical jump height were measured over a 10 week period.
This study found that the athletes who performed Nordics increased their sprint performance over short distances, whereas the athletes not doing Nordics did not.
They also improved their vertical jumps slightly more than those who didn’t do Nordics!3https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5716363/
So the science seems pretty clear: Nordics are going to help your vertical.
Why You NEED To Do Nordics To Jump Higher
So how do Nordics actually help us jump higher?
Obviously they strengthen our hamstrings, but that’s not a particularly important muscle group for the vertical jump, are they?
Triple Flexion Vs Triple Extension
Traditionally, vertical jump prowess was thought to be all about triple extension: how explosively you can extend your ankles, knees, and hips to generate maximum power.
Way Too Much Focus On Triple Extension
Following that logic, people thought that calf raises, squats, and glute ham raises were going to be the best ways to develop your triple extensor muscles: calves, quads, and glutes.
No one really cared too much about triple flexion, because flexion didn’t seem to actually generate power to launch us into the air in any meaningful way…
Shifting The Emphasis To Flexion: Big Results
And then Knees Over Toes Guy came along and started doing everything literally backwards and had amazing success.
Instead of training his calves, he’d train his tibialis anterior.
Instead of focusing on his quads, he’d put more emphasis on his hamstrings.
And instead of his glutes (hip extensors), he prioritized his hip flexors.
Through shifting the focus from triple extension back to triple flexion, Ben Patrick was able to go from a 20 inch vertical jump to a 40+ inch vertical.
Of course he didn’t neglect the extensor muscle groups, but the entire premise of his training was to give a lot more attention to the flexors.
Nordics Help Bulletproof Your Knees
The Nordic curl is an injury-reduction machine.
Two of the three studies I discussed earlier mentioned how Nordics were noteworthy in the prevention of hamstring injuries…
But it goes beyond Nordics…
All triple flexion movements increase our ‘bulletproofing reserve’ as Patrick puts it, which makes us more protected from injuries of any kind.
By stimulating the joint from the opposite direction, the tendons and ligaments get a unique stimulus that helps them develop alongside your muscles.
Injuries Cause You To Jump Lower
Every time you bust an ankle or do a knee, you have to pause training.
You often have to stop lifting which means your muscle and strength will atrophy, and you will also have to stop jumping, which means your explosive capacity will dwindle.
Every time you get injured, it’s a major setback to you achieving your goals of an increased vertical jump.
Flexion Movements Indirectly Increase Vertical Jump
Even if Nordic hamstring curls never directly contribute much to your vertical jump increasing, if you regularly perform them alongside tibialis and hip flexor raises, the chances of you getting injured are incredibly slim.
Think of your vertical jump as though it were money.
Getting injured is like wasting money on $1,500 bottles of Grey Goose at the club…
Every time you don’t get injured, it’s like staying home at night and saving money…
If you choose to save your money, you’ll have more money in the end.
If you can figure out how to not get injured, you’ll have a higher vertical jump in the end!
And no hangover!
If a young and reckless athlete who just wants to jump as high as possible as quickly as possible spends 3 years doing heavy triple extension lifts (i.e. me during my high school career), let’s suppose they get injured 3-4 times during that period.
That means they have to take 3-4 steps backward in order to continue going forward.
If they’re unlucky, one of these steps in the wrong direction might end their career…
If you take the longevity-first approach, and focus on balancing your triple extensors with equally strong triple flexors, you likely won’t get injured at all.
This athlete will have trained consistently the entire 3 years with virtually no setbacks.
They will unequivocally be further ahead than the former athlete 3 years down the road.
Slow and steady wins the race.
By a lot.
While Nordics aren’t considered a triple extension movement and don’t directly contribute much to your power output when jumping, they’re crucial to developing your vertical jump in other ways.
Firstly, they stimulate the knee joint from the opposite direction, which offers your tendons and ligaments a novel stimulus to ensure they also develop at an appropriate rate.
Secondly, Nordics are a great hamstring size/strength builder, which is important for ironing out muscle imbalances.
Imbalanced muscles create force production bottlenecks which lead to vertical jump plateaus.
Lastly, Nordics (as well as all triple flexion movements) indirectly increase your vertical jump by preserving your longevity and ability to consistently train over a long time frame.
Be sure to check out one of the two following articles for more info on the best way to make Nordics a staple in your routine.
Do your Nordics!
But if you’re not going to, make sure you check out my list of the best Nordic curl alternatives!
Lastly, if you’re looking for a more direct way to increase your vertical, be sure to check out my latest roundup of the best vertical jump programs for 2023.