One of the best bicep exercises you can do with amazing benefits to functional strength, martial arts and sports.

We have talked a lot about the enormous utility and benefits of the steel mace. The vast majority of people use it for skill training but we like to use it to develop the body. 

Used right, you can build incredibly strength and size in your arms utilizing the steel mace.

One good example is the "flow curl" that we cover in this video and article.

This movement is more than a bicep curl. It’s a multidimensional exercise that develops so many muscles in your arms and shoulders, the primary target is the biceps though.

When it comes to performance, the flow curl with a steel mace taps into deeper levels of strength, coordination, and adaptability.

Let’s break down why this technique is revolutionizing how we think about arm strength, and how it can be used to grow not just muscles but increase functional strength as well.

Inspiration from Martial Arts

Eero originally designed this exercise after being inspired by numerous clinch concepts of Muay Thai, Tai Chi and Kung Fu.

These styles have long emphasized the importance of full-body integration, fluid motion, and wrist dexterity. You don't get this with the standard bicep curls.

Techniques like the famous “sticky hands” in Kung Fu illustrate how crucial wrist control and forearm sensitivity are in maintaining contact, redirecting force and dominating in close-range combat.

These same principles can be applied when working with the steel mace. This is the amazing discovery Eero has made.

The unconventional weight distribution of the steel mace demands control and awareness - just like you would do when you are clinching and grappling with an opponent. The flow curl mimics this kind of engagement. 

In grappling or striking sports, this translates to better clinch strength, more durable forearms and an intuitive connection between hands and the object—key elements in winning exchanges in both stand-up (clinch) and ground combat (BJJ, wrestling).

The Flow Curl Technique

At first glance, the flow curl might not look much but watch closely, and you’ll see it’s a completely different beast.

This movement involves a circular curling motion, where the steel mace is drawn upward in a spiral path, engaging both supinated (palm-up) and pronated (palm-down) wrist positions in one fluid rep.

This subtle shift not only maximizes arm muscle activation but also builds rotational strength in the shoulders and joint integrity.

As the mace flows through the curl, the practitioner must keep it close to the forearm, hugging the implement tight to maintain balance and control.

This encourages fine motor control of the wrist and forearm, along with activation of deeper stabilizing muscles in the shoulder — especially the rotator cuff.

This makes the flow curl a full-arm movement, targeting:

• Biceps (especially the long head, due to the angled grip)
  
  
• Forearms (due to constant wrist adjustment)
  
  
• Rotator cuff and shoulder stabilizers
  
  
• Grip strength and endurance

Instead of isolating one part of the arm, the flow curl unifies the chain, training the arm as it’s meant to move — fluid, connected, and responsive.

While the aesthetic benefits of flow curls are clear: sculpted biceps, thick forearms, and a strong visual physique, the true advantage lies in functional performance.

This movement forces the body to work in non-linear planes, just like real-world movement.

Whether you’re throwing a punch, catching a fall, or grappling with an opponent, your arms are never isolated, rather they’re part of an interconnected kinetic system.

Training with the flow curl teaches the arms to generate and resist force in unpredictable patterns. As a result:

• Endurance improves, since many stabilizing muscles are engaged at once
  
  
• Grip strength soars, thanks to constant tension and balance control
  
  
• Quicker CNS fatigue leads to deeper strength adaptations, especially in the forearms and shoulder girdle
  
  

This is not a movement for show, instead it’s for those who want their training to carry over into sport, combat, and real life.

Internal Training Philosophy

What separates the steel mace from traditional tools isn’t just its design, it’s the training mindset it demands.

Unlike machines or isolated lifts, mace flow training invites the athlete to turn inward. Properly done these movements requires precision, breath control, spatial awareness, and internal engagement. 

This isn’t about how many reps you can grind out — it’s about how well you move through each one. This is the big difference between our approach and everyone else's.

Mace movements can become a meditative practice, especially when repeated in patterns or combined into a full-body flow. Practitioners can begin to feel how their muscles work in harmony, how the wrist leads the elbow, and the elbow guides the shoulder. 

Over time, this awareness sharpens into instinct—something fighters and elite athletes rely on when milliseconds count.

Training becomes exploration, not repetition.

With the mace, you’re not just building muscles. You’re building body intelligence. You’re learning how your body wants to move, where it’s tight, where it’s weak, and how to unlock new levels of coordination and strength.

This is our internal path of training. We are not obsessed with the amount of weight or how many repetitions we do. We are not obsessed with doing the same swings over and over again.

We are obsessed with how the mace movements develop the body. This is why our approach is internal based.

Skill aspect is an important aspect but it's not the main focus. People who primarily focus on the same movements and chase weights or repetitions are in fact doing skill training and not proper internal strength training.

How we do training is a reconnection to this ancient truth: strength is not just what you lift — it’s about internal development.

When infused with internal principles, mace and Indian club training can become a training tool that conditions the body for battle, for life and for longevity. It trains endurance, control, and power in equal measure.

Whether you’re a fighter, a mover, or someone who wants to train like a warrior without breaking down, then this is your next evolution.

Grab the mace. Feel the flow. Forge the body.

We do exactly this inside the Iron King Method.

Stay strong.