I've been doing CrossFit now for nearly 11 years. Yesterday I scaled another workout. Modified it so that it was better suited for me, I made the challenge easier.
The reason I scaled is because I can get results quicker this way.
Below I have the simple to understand, pointing out the obvious, practical explanation to scaling,
Then below that I have the nerdy, no need to hold this sort of information, probably won't change anything you do in the gym but interesting to understand version.
Switch off where appropriate.
Why we Scale - TLDR
Weightlifting
Go too heavy = Move too slow
Go too light = Not enough challenge
Gymnastics
Movement too hard = Move too slow
Movement too easy = Not enough challenge
Monostructural Work (think running, biking, rowing)
Go too fast = Can't hold the pace
Go to slow = Not enough challenge
With all the movements we have in CrossFit, there is a sweet spot, the perfect challenge, that's just on the edges of our capability. We teach people how to load weights properly, modify movements like push ups to make them easier or harder so everyone at every level can get a good challenge, we teach pacing. A common trick for us is intervals where the score we record is the slowest round.
Scaling for us is finding everybody's sweet spot, the modifications that get the best results.
How to Scale for Nerds... Stick with me
Above we talk subjectively, we want 'challenge' but.. we can actually objectively select the proper scaling option, first, lets define fitness...
The foundations of CrossFit say that fitness can be defined as 'increased work capacity across broad time and modal domains' or more simply 'lift heavy loads, long distances and fast.'
With this, we can use classical mechanics to mathematically define 'Work capacity'
There's two equations we can think about
Work Done = Force x Distance
Power = Work Done/Time
If we take a look at cycling. Its common to use Power, or Wattage, as a test of fitness on the bike. What our capacity is. We can also apply this to CrossFit.
Working Example of Power Output (W)
So, if we take a movement, such as a Front Squat. Lets say in the workout we have to complete multiple sets of 10 reps as part of a workout. We might put 60kg as a target 'Rx' weight.
If I think I can do 60kg, but have to break this into 2 sets of 5 reps to be able to complete it.
Or
I can do it in 1 set of 10 but at 50kg, which gives us the most power output?
For us, this isn't a hypothetical question, its a practical one and we have an answer.
Lets assume...
10 reps of a squat travels a fixed distance, for simplicity lets say the bar moves up 1 meter x 10 reps = 10m (of productive force, we're simplifying things, ignoring the lowering phase, giving gravity the credit on this one). Force is typically measured in newtons, so 1 kg is around 10 newtons (we're rounding again, its 9.81 but simple abstractions will do)
Lets then assume I can do 1 rep in 2 seconds, so need 20s of moving time, and if I rest, I would rest for 10 seconds before picking up the bar again.
So
500N*10m/20s = 250W
600N*10m/30s = 200W
If you followed this... the one that leads to the greatest production in power is the lower weight of 50KG
Perfect! Scaling produces more power! So, for us, this is the quickest way to get results.
Broad Time & Modal Domains
Does this mean light weights are always best....
Nope, if we take the example above, 40KG would also lead to decreased power output (assuming rep speed stays consistent), works out as 200W, same output at 60KG.
Also, if we zoom back out remember fitness is 'increased work capacity across broad time and modal domains'
Broad time and modal domains. This means we want differing challenges. For the workout above, the challenge is 10 reps and we want to be able to keep moving.
Another day we might want to do a 10 Minute AMRAP chipper of just Front Squats! I won't ever program this one. Another time we could go for 2 heavy reps every minute for 10 minutes. We could pick any movement, any rep range. The goal, to increase the Work Done, or more often, the Power we produce throughout the workout.
Sometimes we want the challenge to be lighter more endurance, sometimes we want it to be heavy. We vary the movements and challenges, just like we have various physical challenges in in life, we do in workouts. We want to become capable all rounders.
Scaling is an objective thing, there is a right level for everybody to maximize the effectiveness of workouts. We teach you how.
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