What do Engineers and Strength Coaches have in common? Engineers use an understanding of the latest in Physical Sciences to apply solutions to real world challenges and design problems. Similarly, Strength Coaches apply the latest in Life and Exercise Sciences to develop solutions for improving human strength performance. Both Engineers and Coaches combine sciences with empirical and anecdotal (gasp!) evidence to apply the best possible solutions based on what we think we understand to-date.
That said, today we're going to explore possible applications of the Reverse Nordic Curl for Strength Athletes. First, we'll start by defining what a Reverse Nordic Curl is. Once we've developed a broad understanding of the movement, we'll briefly review quadricep anatomy before reviewing evidence in support of its use. Finally we'll review benefits, applications, and implementation guidelines for Strength Athletes.
Disclaimer: I am not a medical professional or physical therapist, so proceed with CAUTION and consult one before implementing Reverse Nordic Curls into your training for serious injury rehabilitation purposes including but not limited to post-op athletes.
DEFINITION
Reverse What Now?
A Reverse Nordic Curl, hereinafter Reverse Nordic, is literally the opposite of the Nordic Curl which focuses on developing the posterior chain, specifically the hamstrings. The Reverse Nordic starts with a person kneeling on their shins, then lowering their upper body backward in a controlled manner towards the ground as far as their mobility allows, then finally reversing the movement by contracting their quads to bring themselves back into the kneeling position. The movement requires maintaining tension in the abs, quads, and glutes to keep the upper body as rigid and controlled as possible so you don't hit your head on the floor. The first portion of the movement is a loaded eccentric, meaning we are lengthening and contracting the quads at the same time. The second portion of the movement is a contraction or shortening of the quads to "push" you off of the floor. The movement is essentially a bodyweight leg extension, but instead of pushing an external weight like with a traditional machine, you are pushing against the ground with your shins to return to the starting position.
QUADRICEP 101
Before we dive into the benefits of this movement, let's do a brief overview of the quadriceps. As the name implies, there are four muscles in this group which are the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. Of the four muscles in the quads, ONLY the rectus femoris crosses multiple joints to perform two functions which are 1) leg extension and 2) hip flexion. The other three muscles only perform leg extension.
The muscles targeted in the Reverse Nordic are the quadriceps, however, when performed with full hip extension, this movement also works the rectus femoris in a way that typical squat and lunge patterns can't. As you can see on the right, at the bottom of the squat, the hips are fully flexed meaning the rec fem is in it's shortest position for the movement. To get out of the bottom of the squat, your body switches to the other three quad muscles to extend the leg since relying on the rec fem would mean more hip extensors are required to overcome the hip flexion generated by the rectus femoris. Your body is smarter than you think and activates muscles in the most efficient manner to get the job done.
Loading the Rectus Femoris
As we've seen above, loading the rec fem is TRICKY business using the typical squat and lunge patterns since flexing your hip WHILE extending your knee would cause your butt to shoot up and dump the bar forward. This is where the body builders got it right... Using a leg extension machine is a great way to load all of the quad muscles since the rec fem is in a slightly lengthened position at the hip. However, you would need to remove the back seat of a leg extension machine and lie down backwards to fully extend the hip and lengthen the rec fem, which is not possible on most leg extension machines I've seen and probably frowned upon at most gyms. You could probably rig up something on an incline ab bench and attach dumbbells with monkeyfeet, but you would look way cooler doing a Reverse Nordic curl.
EVIDENCE
For all you evidence-based junkies out there (you know who you are), below are some studies and findings important to note before deciding why and how to implement Reverse Nordics into strength training.
Empirical
Studies have shown that activation of the rec fem is low in multi-joint exercises requiring both knee extension and hip flexion. This means we should be using movements with an extended hip to train the rec fem.
The rectus femoris is the most commonly injured quad muscle in sports with repetitive kicking and sprinting. Studies have shown that Reverse Nordics can be used for injury prevention and rehabilitation, specifically for quad strains in the rectus femoris. This means using the Reverse Nordic for injury prevention and rehab in strength athletes is likely a viable application of the movement.
Studies have shown that performing the eccentric of a Reverse Nordic increased muscle fascicle length, muscle thickness, pennation angle, and cross-sectional area of the rec fem. This means eccentric loading of the movement stimulates increased muscle size of the quads particularly the rectus femoris.
Anecdotal
My personal experience has shown whenever I feel pain in the hip flexors and/or at the top of my knee, programming Reverse Nordics after heavy compound movements improves or eliminates the issue. This suggests that the findings noted above can be reasonably applied to Strength Athletes.
BENEFITS
Now that we have a basic understanding of quadricep musculature and how the rectus femoris functions, let's review some of the benefits of implementing Reverse Nordics for Strength Athletes taking into account the findings noted above, as well as other benefits not specifically referenced.
Full Quad Development
As noted in the studies above and from how your body actually operates, we know that the rec fem gets neglected in compound barbell movements. Programming Reverse Nordics can help develop musculature that squats and leg presses can't. While leg extensions also activate all of the muscles in the quads, the Reverse Nordic performed with a fully extended hip provides the most activation of the rec fem.
Injury Prevention and Rehab
Even though Strength Athletes are not sprinting or kicking (at least for the sports they are trianing for), the angles of leg extension with a flexed hip are similar, so using Reverse Nordics in your training can help reduce risk of injury or rehab an already injured or strained muscle.
Minimalist
You don't need any special equipment, just a floor, your body, and the willingness to learn and progress the movement!
Increased Mobility
This movement can help with tightness in the hip flexors or quads.
APPLICATIONS
Below is what I would recommend based on whether you are or are not experiencing pain in the hip flexor and/or the top of the knee. All of these applications should be Regressed or Progressed as noted below under IMPLEMENTATION to hit the prescribed reps and sets.
Post-Op Athletes for Knee, Quad, Glute, Hip Muscle or Tendon Injury - NOT RECOMMENDED
Seek guidance from a medical professional or physical therapist
Pain Near Hip Flexor and/or Above Knee Applications
Gradually work up to 4 to 6 reps for up to 2 sets @ RPE 7 to 8 with focus on long controlled eccentric
1 to 2 times per week at the end of training session or on separate conditioning day
No Pain - Injury Prevention Applications
Gradually work up to 4 to 6 reps for up to 3 sets @ RPE 7 to 8 with normal tempo controlled eccentric
1 to 2 times per week at the end of training session or on separate conditioning day
No Pain - Hypertrophy Applications
Gradually work up to 6 to 12 reps for up to 4 sets @ RPE 7 to 8
1-2 times per week as part of your normal training session
IMPLEMENTATION
Below are a few methods for regressing or progressing your Reverse Nordic Curl based on your capabilities, mobility, and tolerance for knee flexion and hip extension.
Regressions
Can't do a full Reverse Nordic Curl? No Problem! You can still reap many of the benefits from regressed versions of the full curl that can be done in isolation or combination.
Regression 1 - Reduced Hip Extension
Slightly flexing the hip shortens the rec fem while also shortening the moment arm about the knee, meaning there is less torque to overcome but also less activation of the rec fem
Regression 2 - Reduced Range of Motion
Gradually working towards the full range of motion may take time but partial range of motion will still engage the rec fem, just with less moment arm about the knee
Regression 3 - Band Assisted
Similar to using a band to assist a pullup, bands can be used to increase range of motion, if mobility and tolerance allows, by reducing the torque requirements about the knee at further ranges of motion
Progressions
If you've mastered the regular full range of motion Reverse Nordic Curl, you can make them harder with the following progressions that can also be done in isolation or combination:
Progression 1 - Arms Extended Over or Behind Head
Extending the arms over or behind your head will lengthen the moment arm about the knee by moving your center of mass further out, meaning there is more torque to overcome throughout the movement
Progression 2 - Tempo
Increasing the duration of the eccentric portion of the movement will increase difficulty of the movement without adding external weight or changing arm positions
Progression 3 - Added Weight
Just like any movement, these can be loaded with a weighted object of your choice by holding it at chest level to increase the moment about the knee
Holding the weight above your head is crazy, but if you can do it, please be sure to let me know, I'd love to learn how you were able to progress to that level!
THANK YOU!
Reverse Nordic Curls are a great tool to add to your arsenal of movements. If you found this post helpful, be sure to like, share or comment below!
REFERENCES
1) Ema R, Sakaguchi M, Akagi R, Kawakami Y. Unique activation of the quadriceps femoris during single- and multi-joint exercises. Eur J Appl Physiol. 2016 May;116(5):1031-41. doi: 10.1007/s00421-016-3363-5. Epub 2016 Mar 31. PMID: 27032805.
2) Vigotsky, Andrew & Bryanton, Megan. (2016). Relative Muscle Contributions to Net Joint Moments in the Barbell Back Squat.
3) Kubo K, Ikebukuro T, Yata H. Effects of squat training with different depths on lower limb muscle volumes. Eur J Appl Physiol. 2019 Sep;119(9):1933-1942. doi: 10.1007/s00421-019-04181-y. Epub 2019 Jun 22. PMID: 31230110.
4) Alonso-Fernandez D, Fernandez-Rodriguez R, Abalo-Núñez R. Changes in rectus femoris architecture induced by the reverse nordic hamstring exercises. J Sports Med Phys Fitness. 2019 Apr;59(4):640-647. doi: 10.23736/S0022-4707.18.08873-4. Epub 2018 Oct 1. PMID: 30293403.
5) Mendiguchia J, Alentorn-Geli E, Idoate F, Myer GD. Rectus femoris muscle injuries in football: a clinically relevant review of mechanisms of injury, risk factors and preventive strategies. Br J Sports Med. 2013 Apr;47(6):359-66. doi: 10.1136/bjsports-2012-091250. Epub 2012 Aug 3. PMID: 22864009.