Louie Simmons owns Westside Barbell which is widely regarded as the strongest gym in the world. His training methods go well beyond just power lifting. Simmons and Westside have produced more than 100 world records but they also train NFL players, Olympic gold-medal winning sprinters and MMA fighters. When it comes to weight training, something Louie said genuinely resonated with me.

“Look at weightlifting as fast or slow, not heavy or light” – Louie Simmons

At first glance, this may seem like simply taking one thing and calling it something else. But when you dig deeper, you can see the genius in the simplicity.

After an initial neurological adaption (where new lifters can see rapid gains), the real works begins. What’s the best way to get stronger? Is it lifting light weight for higher reps? Heavier weight for fewer reps? Is there an ideal strategy? It turns out that the answer is yes and it goes beyond rep scheme and one-rep max percentages.

A Primer on Physics

Whenever we lift weights, we are exerting force against the barbell. In physics, we measure force using Newton’s Second Law of Motion via the equation f = ma, or put differently, force is equal to mass multiplied by acceleration. To generate more force, we must either increase mass or acceleration (or both). We measure force in terms of Newtons (N) which we can also translate into other measurements including horsepower. More on that some other time.

Without diving too deep into my WPI curriculum, let’s focus on the squat for now and define force in terms of what I will refer to as a CrossFit Worcester Force unit of measurement (a CFWF). The average athlete moves the bar approximately two feet from the bottom of the squat to the top. To that end, a CFWF would measure how much weight an athlete can squat (mass) and how quickly he/she can move that weight over that two feet (acceleration) and it ignores bodyweight.

Heavier weight moves slower; lighter weight moves faster (up to a point). Here is where Louie Simmons meets physics. Let’s consider someone with a one-rep max back squat of 400 pounds and let’s break down how quickly that person might be able to move different squat weight from below parallel to lockout:


  • 100% of 1RM = 400 pounds moved 2 feet in 1.00 second = 800.0 CFWF (400 x 2 ft / 1.00s)
  • 80% of 1 RM = 320 pounds moved 2 feet in 0.70 seconds = 914.3 CFWF (320 x 2 ft / 0.70s)
  • 60% of 1 RM = 240 pounds moved 2 feet in 0.55 seconds = 872.7 CFWF (240 x 2 ft / 0.55s)
  • 40% of 1 RM = 160 pounds moved 2 feet in 0.50 seconds = 640.0 CFWF (160 x 2 ft / 0.50s) – remember, we can only move weight so fast


After studying weightlifting for decades, what Simmons and Westside Barbell advocate is proved valid by physics. Not only does it matter what weight you lift, it matters how fast you lift it. In Louie’s words – “look at weightlifting as fast or slow, not heavy or light”.


In the theoretical examples above, lifters generate more force at 60% – 80% of their one-rep max than they do above or below those levels. It turns out that this holds true in real life. What Simmons has found is that progressive overload works best when training in the range of 65.0% – 82.5% of your one-rep max provided you are moving the weight as fast as you can! Think in terms of fast or slow, not heavy or light!

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Beyond my respect for Louie Simmons and physics, how do these findings compare with other notable strength coaches and theories? Jim Wendler authored perhaps one of the simplest and most effective strength guides available today known to most as “Wendler 5/3/1”. The Wendler system has athletes working with 63.0% – 81.0% of their one-rep max – essentially identical to what Simmons’ prescribes for Westside lifters. Simmons just takes it one step further and correctly insists that speed – how fast an athlete can lift the weight – must also be a focus.

We’ve designed CFW’s strength program with all of this research in mind. So when you lift, focus on tempo and explosiveness to maximize force, and by extension, to get stronger.