LegFlexx: Transforming The Seated Leg Curl With Flywheel Overload and Feedback Technology

Introducing our latest innovation in flywheel-based training, a single-exercise machine designed to target a specific muscle group: the hamstrings. CEO Fredrik Correa introduces the LegFlexx:

Key Points:

  • We built the best hamstring isolation device on the market. Slightly biased but you’re welcome! 
  • Loaded with flywheels you’ll enjoy truly efficient training at every angle, during every rep. 
  • We made it seated, for working longer muscle lengths to build long and strong hamstrings, ready to perform and more resilient to injury. 
  • Seated leg curl machines have shown 55% more gains in muscle mass vs prone leg curl, and it lets you watch the world go by when working your hamstrings. 
  • No more cramps in the lower back. 
  • Half the weight, half the floor space needed, and portable on wheels. Freeing up your real estate for more flywheel devices!


From Idea to Implementation: The Need For a Leg Curl Machine

The leg curl exercise is amongst the most common strength training exercises. In our efforts to continuously transform traditional exercises, the leg curl exercise constituted a strong candidate as there hasn’t been much development in the last years with regards to traditional leg curl machines.

In our first-ever single-exercise flywheel machine, the LegExx, we merged a traditional exercise, the leg extension, with our market-leading flywheel and sensor technology, the kMeter feedback system. Since its launch, the LegExx machine has received wide acclaim among the #ExxentricFam and we see this as proof that you are ready for the next single-exercise flywheel machine. 

The leg curl exercise is a standard exercise that’s already possible to do on our signature flywheel devices, the kBox (kBox Leg Curl) and the kPulley (kPulley Leg Curl). However, we wanted to develop a single-exercise machine fully optimized for the leg curl exercise. This has also been a very common request from our users, especially our LegExx customers. We spent a lot of time thinking about this because there are decent traditional leg curls out there, and when making ours it really needed to have a purpose and fill a gap. 

Isolation devices can be a safe and effective way to train specific muscles. In some cases, isolation is even considered better than compound or more complex movements. This is because you can focus on a specific muscle or muscle group whereas in a complex movement an injury or weakness might be “hidden” while the work gets performed with other than the desired muscles. 

LegFlexx vs. Traditional Leg Curl Machines

The prone, or lying, leg curl machine has traditionally been used to work the hamstrings. However, the prone position is just not optimal because it works the muscles at a fairly short muscle length (and it also cramps up the lumbar back too much in my opinion). This is compensated in part with a 30° angle in the hip in newer devices. That’s better, but the problem is still there. 

Working at longer muscle length is beneficial for many reasons but one of the main ones for us was that the hamstring injuries happen in the end of the eccentric phase during running when the leg has swung forward and is about to go into the ground at which the hamstrings in that leg are elongated. 

Our brand new LegFlexx is designed to curl at a 90° angle at the hip. One study comparing two weight-stack devices head-to-head prone vs seated showed 55% more hypertrophy in seated vs prone leg curl. Do you want to leave those gains on the table? We know preventing hamstring injuries is about making the hamstrings “long and strong” so the combo of seated curl, flywheel, and overload is a game-changer here. 

On top of that, floor space is the gym’s real estate. It doesn’t matter if it is your home gym or a huge facility, you always need more space.  If you aren’t already convinced by a flywheel-based and more efficient device, working your hamstrings at more optimal length and much more comfortable, how about it only taking up less than half the floor space too? 

Additionally, without the load from the weight stack and the built-in wheels, you can also move it around whenever you want, making it an extremely flexible solution. Use it in group sessions or create stations for your athletes or clients in your facility, based on their program for the day. 

Flywheel Training and Sensor Technology 

In the Exxentric LegFlexx, we wanted to combine the benefits of variable resistance, real-time training feedback and eccentric overload. 

  • Variable Resistance: The LegFlexx can be mounted with up to six flywheels of any size from XS to XL, giving it a range of inertia from 0.005 to 0.420 kgm2. 
  • Real-Time Training Feedback: The LegFlexx communicates with our kMeter app through a built-in sensor, automatically measuring and tracking the users’ workout sessions.
  • Eccentric Overload can easily be achieved either with the user-controlled lateral overload method or by the spotter-assisted overloaded concentric action method. Use kMeter to track the overload and prepare yourself for an intense workout. 

LegFlexx & LegExx Combo

The new LegFlexx has partly similar specifications and features as its sibling the LegExx, like its dimensions, adjustable range of motion, portability, integrated kMeter feedback system, coach-assisted eccentric overload, and variable resistance from the same inertia loading capacity. The key difference is that the seated leg curl machine is built to optimize your hamstring muscle growth. 

Together, they are a super strong combo and a must-have for any gym, offering game-changing isolation training to two really important muscle groups. Whether you are training for performance, rehabilitation, or fitness, our LegExx + LegFlexx combo is a great addition to your arsenal.



Let The Leg Flexx and Happy DOMS!

Exxentric's CEO Fredrik Correa

Fredrik Correa, M.D., CEO

Follow @fredrik_correa




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