The only set to set workout supported by accredited strength training organizations is progressive, increasing workload from one set to another. No one recommends reducing workload from one set to the next.
Pyramid Workload
I do not read trendy articles regarding strength training. I have been reading research papers regularly for the past 20 years.
NOTE: The term workload does not refer to volume based but percentage of 100% of 1RM regardless of number of reps. Some refer to load, loading, and workload as the sum of reps times the resistance, which I would refer to as volume.
Set to Set
There is no current research, that I know of, that supports reducing the workload from one set to the next. If anyone knows of any research that supports a reduction in Workload from one set to another I would like to see it. I am not looking for somebody that just says this and that as if they are an authority. Research where it is based on outcomes from a well-designed controlled studies that provide a consistent pattern of findings. Research that had substantial number of studies involving a substantial number of participants.
Day to Day
For advanced training there is support for a variation, up and down in workload from one workout day to the next. This does include weeks with a pyramiding pattern of light and heavy days. This is referred to as Micro Periodization. A micro cycle is in the range of 2 to 12 workouts, typically one week.
Week to Week
A Periodization Mesocycle is a period of 3 to 6 weeks, typically 4 weeks. There is somewhat of a pyramid pattern. The first is an unload period where the workload is reduced 5-10% below current capacity. The next period, reload, ramps up to current capacity. The following two periods overload, and adapt is where progression ramps up. The ramp is steepest (5-8%) for novice untrained individuals. For advanced individual the progression is reduced to about 1%. This concept is nearing industry consensus.
Month to Month
There is no pyramid pattern in workload of Mesocycles within a Macrocycle. The variations in a mesocycles is volume and intensity. Research has not reached a consensus on the effectiveness of a variety of volume and intensity cycles.
Summary
The above is a very generalized description of Classical Periodization.
The question asked was about reducing workload within a workout. There is no evidence to support a pyramided daily workout. All research take a progression stance. Ramp up.
The link to Progression Models in Resistance Training for Healthy Adults near the top of my post supports what I have stated here. This report is a Position Statement from the American Academy of sports Medicine. It is based on a substantial number of studies.
When I think of pyramiding I am thinking set rep scheme. Where a pyramid is something like:
4 reps
7 reps
4 reps
Inverse pyramid:
7 reps
4 reps
7 reps
The % of 1RM should always progress from set to set. At between 8% and 12% between each set.
This is a good paper on that subject:
Progression Models in Resistance Training for Healthy Adults
On the page the above link takes you to there is a full text PDF listed on top of the right hand column.
When making a routine you should start with your set rep scheme.
Let's say you are working out 3 day per week, High Intensity, High volume
set 1, 2, 3
day 1: 12,10, 9
day 2: 10, 9, 9
day 3: 9, 9, 8
The calculate your weight of each set:<br>
80% of 12RM (.8 x .70 x 1RM)
90% of 10RM (.9 x .75 x 1RM)
9RM (1 x .77 x 1RM)
This way you get the variation in reps per set while progressing the effective workload. While your set rep scheme gives you your Pyramid, Inverse Pyramid, Ramp Up, Ramp Down, etc.