It would be nice to see the full studies. Per the abstracts, two of the studies suggest KB swings were useful while the other said it was inferior to weights (as you stated).
However, it’s unclear the fitness level of the participants. My guess is that they are not “athletes” and thus the results shouldn’t be assumed to be accurate for athletes.
I’m not sure what I believe per KB Swings. I’m not ready to jump on either band wagon yet.
“Athletes” is right. With 34 kilo “power” cleans, 22 cm “verticals” technically improvements are happening with “healthy” participants. KB swings are loaded exercises and are great for the fitness community but are they producing freaks?
It’s important to read the full studies as you will see the details that I listed above, proving that yes people who workout twice a week will get better, but I think that’s not what’s holding back the women’s shot or discus. For example look at hypertrophy in six weeks, do we see slabs of muscle being put on the “healthy participants” ? No.
So yes leg extensions of 2 sets of 6 reps will help old people fight sarcopenia but that protocol may not help elite athletes take it up a notch. Based on the research KB swings for time ala “Power to the People” is 16 kilo repeat squatting for time, something nobody is advocating.
When we are citing research that documents loading with weights with RPE we need to rethink what we consider evidence.
Star61 is right, technically KBs should be treated as an exercise that elicits a sufficient stimulus to help a health population improve strength and power. The question is compared to what?