Strongman Underbelt Guide: Benefits, Dual-Belt Systems

If you have ever watched a World’s Strongest Man competition, or walked into a gym where the “heavy hitters” train, you have likely noticed a specific trend in gear. It’s not just the tacky on the forearms or the knee sleeves; it’s what is happening around the waist. Specifically, the fact that most athletes aren’t wearing just one belt—they are wearing two.

Welcome to the world of the Strongman Underbelt.

While the thick, rigid lever belt gets all the glory for bracing, the unsung hero of strongman gear is the soft, neoprene layer sitting underneath it. Whether you are training for your first novice comp or you are a seasoned competitor looking to optimize your moving events, understanding the mechanics of the underbelt is crucial.

In this guide, we break down exactly what an underbelt is, the science behind why it boosts performance, and how to fit one into your dual-belt system.

5 Key Takeaways: Why Wear a Neoprene Underbelt?

Before we dive deep, here are the top five facts you need to know about underbelts in Strongman:

Material Matters: They are almost exclusively made of 7mm thick neoprene (similar to knee sleeves) with a Velcro closure, designed for warmth and compression.
Performance Boost: Research suggests wearing a belt can increase strength capacity by up to 15% and increase Intra-Abdominal Pressure (IAP) by 25-40%.
The Dual-Belt System: They are engineered to work in tandem with a rigid lever belt, creating a friction-lock that prevents gear from sliding during dynamic movements like the Atlas Stones.
Event Specific: While great for max static lifts, they are often worn “solo” for agility events where a leather belt restricts movement too much.
Competition Safe: They are generally compliant with major federation rules, such as the WHEA and WSF, as long as they fit within standard equipment specifications.

What is a Strongman Underbelt? (Neoprene Back Support Explained)

At its core, a strongman underbelt (often listed as a neoprene back support) is a wide, flexible support belt. Unlike a powerlifting belt, which is usually made of 10mm or 13mm rigid leather, the underbelt is constructed from 7mm neoprene.

If that thickness sounds familiar, it is because it is the same material and thickness used in high-quality knee and elbow sleeves. The belt is fastened using a heavy-duty Velcro strap rather than a prong or lever.

The Design Philosophy

The goal of the underbelt is not to provide the “hard wall” bracing that a leather belt does. Instead, it serves three distinct purposes:

Thermal Insulation: It keeps the lower back, hips, and obliques warm. In a sport where you might rest for 20 minutes between events, keeping the lumbar area hot is vital for injury prevention.
Proprioception: The compression against your skin provides sensory feedback, reminding you to keep your core tight even when you aren’t under a heavy load.
The Base Layer: It acts as a protective gasket between your body and your rigid outer belt.

Performance Benefits: How the Dual-Belt System Works

You might be asking, “If I have a high-end lever belt, why do I need a neoprene layer underneath it?”

The answer lies in Intra-Abdominal Pressure (IAP) and skin mechanics.

The Science of the Squeeze

When you brace for a heavy deadlift or log press, you are expanding your abdomen against your belt to create stability for your spine. Studies on belt mechanics indicate that using a lifting belt can increase IAP by 25% to 40% compared to lifting beltless. This surge in pressure acts like a balloon inside your torso, rigidly supporting the spinal column and reducing compressive forces.

Furthermore, increased stability can lead to a roughly 15% increase in strength capacity. The underbelt amplifies this by filling the gaps. A rigid leather belt is a fixed circle, but your body is not. The soft neoprene of the underbelt contours perfectly to your hips and ribs, filling the negative space between your body and the leather belt.

1. Preventing “The Pinch”

Dynamic events are brutal on the skin. If you have ever done a Continental Clean with an axle bar, or lapped a heavy Atlas Stone, you know that a leather belt can dig into your hips and ribs, causing severe bruising. The underbelt acts as armor, absorbing the bite of the leather edges.

2. The Friction Lock

One of the biggest annoyances discussed in equipment reviews is the belt sliding up during a movement. When you are cleaning a log, you have to extend your thoracic spine. Often, a leather belt will slide up your torso during the clean, leaving you unsupported for the press.

Neoprene has a high coefficient of friction. When you clamp a leather belt over a neoprene underbelt, it locks in place.

Best Strongman Underbelts: Strength Shop, Cerberus & More

Not all neoprene is created equal. When sourcing an underbelt, you want to avoid cheap “slimming” belts. According to community consensus, the top contenders usually fall into the £35-£55 ($45-$75) price range.

Strength Shop Underbelts: Known for popularizing the 7mm neoprene belt. Their belts are a staple in the European strongman scene.
Cerberus Strength: Offers highly durable options, often with additional grip technology on the inside to prevent the belt from spinning around your waist.
Rehband/SBD: While known for sleeves, their “warm pants” or belt options are also used, though Strength Shop and Cerberus are more specialized for the dual-belt setup.

What to look for:

Thickness: Must be roughly 7mm.
Width: Usually 4 to 5 inches wide on the sides, sometimes widening at the back.
Closure: Heavy-duty, industrial-grade Velcro.

How to Wear a Strongman Underbelt (Tightness & Positioning)

How tight should the underbelt be? This is a “Goldilocks” scenario.

Too Loose: It will slide around and bunch up under your leather belt.
Too Tight: You will struggle to get a full breath into your belly for bracing, effectively lowering your IAP.

The Rule of Thumb: Pull the underbelt tight enough that it stays in place on its own and provides a comforting “hug” to your midsection, but loose enough that you can still push your stomach out against it. Remember, the outer leather belt provides the maximal tightness; the underbelt provides the foundation.

Positioning: For most events, the underbelt is worn slightly lower than the leather belt, covering the iliac crest (hip bone). This prevents the leather belt from digging into the hips during squats or yoke walks.

Competition Rules: Are Underbelts Allowed?

Before you invest in gear, you need to know if you can wear it on game day.

The good news is that underbelts are widely accepted across almost all Strongman federations, including the World Heavy Events Association (WHEA) and World Strongman Federation (WSF).

The Caveats:

Total Thickness: Some federations have rules about the maximum thickness of equipment. If your underbelt is extremely thick and your leather belt is 13mm, you might push the limits of what is allowed.
No Rigid Inserts: The underbelt cannot have hard plastic or metal supports inside it.
One Rigid Belt Rule: You can generally wear an underbelt and a leather belt, but you cannot wear two leather belts.

Always check the specific rules of your federation or promoter.

FAQ: Common Questions About Neoprene Belts

1. Is there a difference between an underbelt and a back support belt? In terminology, yes; in practice, usually not. In Strongman, we refer to “neoprene back support belts” as underbelts. However, avoid medical-grade back braces with hard plastic spines. You want 100% neoprene.

2. Can I use an underbelt by itself? Absolutely. Many strongmen wear only the underbelt for moving events like the Loading Race or Tire Flip. It provides warmth and light support without restricting your ability to bend over and breathe rapidly.

3. How tight should I wear it? It should be snug, but not suffocating. You must be able to expand your diaphragm. If you turn purple before you even put your leather belt on, it’s too tight.

4. How much do they cost? They are an affordable investment compared to other gear. Expect to pay between £35 and £55 ($45 – $75) for a high-quality brand like Strength Shop or Cerberus.

5. Does wearing a belt weaken my core muscles? No. This is a persistent myth. Research shows that wearing a belt actually increases the activation of the rectus abdominis and erector spinae muscles. The belt gives your muscles something to push against, leading to a harder contraction.

6. Does thickness matter? Why 7mm? Yes. Thinner belts (3mm or 5mm) tend to roll over on themselves when you bend forward. 7mm provides enough rigidity to keep the belt’s shape while remaining flexible enough to be comfortable.

7. Should I use it in training or only competition? Train how you compete. If you plan to use a dual-belt system in a contest, you need to get used to the bulk and the feeling of it in the gym. Using it in training also keeps your lower back warm, reducing the risk of strains.

Final Thoughts

In the brutal sport of Strongman, longevity is the name of the game. The underbelt is one of the few pieces of equipment that offers both a performance advantage and a safety advantage. Whether you are looking to add pounds to your deadlift or simply want to survive a heavy yoke walk without bruised hips, the neoprene underbelt is an essential piece of the kit bag.

Underbelts in Strongman Training