When it comes to fat loss, ever wondered who hits harder, BIG or FAST?

Toni did when he asked…

“I have a question regarding weight loss and punching power. Let’s imagine we have 2 genetically identical fighters…

Muay thai fighter 1 weighs 90 kg but is physically less muscular and fat.

Muay Thai fighter 2 weighs 78kg but is physically fitter, has more muscle mass through maximum strength, explosive and speed strength training.

Which of the two hits harder? The heavier or the fitter?”

I love this, it’s right up my street! I’m going to use some simple physics to reveal exactly who wins this punching contest and why!

by Don Heatrick

Big Or Fast, Who Punches Hardest?

In this episode we’ll prove if being heavier, or being faster results in the hardest punch, so you can decide if losing body fat will reduce your KO ability, and how to best train to deliver the most destructive strikes possible.

Taking Toni’s question, I’m going to standardise it to make it a fair test, and we can see who would REALLY hit harder

We’ll assume both fighters have the same level of Muay Thai technique and relative strength for their muscle mass. We’ll then make this a little more extreme than Toni’s  proposed example, and say that both fighters also have the same amount of muscle mass

  • Fighter 1 weighs 90kg, has 22% body fat, and has 70.2kg of lean muscle mass
  • Fighter 2 weighs 78kg, has 10% body fat, and also has 70.2kg of lean muscle mass
big or fast fighter

So literally the only difference between these two fighters is 12kg of body fat. Fighter 1 is just over 15% heavier, but has no strength advantage. 

Because both fighters have the same amount of muscle mass and strength, their force production is the same. But Fighter 2 has less mass, and being 12kg lighter will accelerate over 15% faster according to Newton’s 2nd law of motion (F = m x a).

Just like you’ll lift yourself quicker on a chin up bar if you don’t have extra weight added to you.

big or fast newtons 2nd law of motion

Accelerating faster means that Fighter 2 will reach a higher striking velocity by the time the punch lands given the same range or distance.

So now we really are comparing who hits harder, the heavier fighter or the faster fighter.

We’re comparing weight and speed, which is mass and velocity in scientific terms.

And using those two variables we can check out which combination generates the most destructive strike. And the best measure for this is kinetic energy.

Practical tests using arrows penetrating targets show that the greater the kinetic energy, the deeper the arrow sinks into the target. And the same is true of our punch too.

big or fast arrow kinetic energy and penetration depth

When we look at the kinetic energy of a strike, both mass and velocity matter. But, velocity is squared in the equation, making it twice as important.

Very simply…

If you double the MASS, you double the kinetic energy.

But if you double the VELOCITY, you quadruple the kinetic energy!

In our example, despite being lighter and by virtue of being faster, Fighter 2 will be capable of hitting harder than the heavier Fighter 1 because they have a higher strength to weight ratio.

Kinetic Energy big or fast
big or fast winner

So either, or both reducing body fat while maintaining muscle mass, or training to increase neuromuscular strength without gaining muscle mass, will both increase your force production and your potential to explode faster, creating more kinetic energy and more KO power.

And if you want help understanding how to build neuromuscular strength, or reducing body fat while maintaining muscle mass and strength, I’ve put links to further resources for you on the show notes page for this episode too.

Every so often, an opportunity emerges that can redefine how we train, fight, and thrive.

Today marks one such epic day! The coveted Heavy Hitters Barebones program is swinging its doors open – a golden chance that surfaces just twice a year.

Heavy Hitters Barebones

Doors Remain Open For…


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Why does this matter for every western Muay Thai enthusiast, fighter, or coach?

Why Heavy Hitters is Different:

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If tales of triumph intrigue you, delve deeper into Jonathan Lane’s saga – from grappling with an ACL recovery amid fatherhood to clinching the MTA NSW State Title. His secret weapon? The Heavy Hitters program.

Seize your golden chance to level up your Muay Thai journey. Remember, the doors to Heavy Hitters Barebones will shut on midnight 31st May and won’t swing open again until November 2024…

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Discover Everything About Heavy Hitters Here!

Don Heatrick

Founder of Heatrick Strength and Conditioning

Don Heatrick is a family man from the UK, former mechanical design engineer, European Muay Thai silver medallist, former pro Thai boxer (ranked 4th in UK while aged 40-years), a Muay Thai coach, podcast host, and the go-to expert on Muay Thai performance training with over 25 years of coaching experience.

Don helps ambitious fighters and coaches take their game to the next level by bridging the gap between Strength & Conditioning, Performance Science, and Muay Thai.

Follow Don Heatrick on Instagram: https://www.instagram.com/donheatrick/

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