S&S swings is alactic work+aerobic recovery “IF” you do not crunch the rest intervals, whether driven by ego or, “it feels easy today”. For the plan to work, you have to stimulate the body for the adaptation you seek.
That you can do more work in less time (condensed S&S swings), on any given day, does not mean you are stimulating the proper cellular adaptations, and so, you will hit a wall in your training, re: not make it to the next bell size, or not achieve 100 x swings in 5 min with your current bell.
The “thing” that you should be trying to stimulate with this protocol is doing more work under aerobic-dominant fueling. This takes patience and discipline. Rest longer, be patient, do the work, and over a short period of time, you will increase your work output while still being aerobic. Then, you can “test” while fueled predominantly by glycolysis. Whatever your test outcome, go back to training under aerobic fueling.
Just because glycolysis is always there to kick in, like a turbo charger, and increase your output, does not mean that this is also the goal of your training. So, rest longer… do not forcefully reduce your rest periods… let your body adapt and your rest periods will natrually decrease… I’m certain that I read this some place before…. ;]
There is some anecdotal evidence that if you train properly and patiently, you can achieve 100 x swings in 5 min while being aerobic. So, train to a HR, or lactate threshold, or rest longer during your swings—whatever you like to call it–but training is different from competing.