With the gym shutdowns I got into kettlebells, and I LOVE THEM. The debate at hand; are they enough? Enough I will define as increasing muscle mass and performance. I'll kick things off with a YES. For starters, even when lifting heavy, kettlebells are more efficient. Not dealing with racking, unloading, waiting, moving station to station allows you to get a ton of output in 30 minutes. Additionally, being kettlebell movements (usually) work in multiple planes of motion, you hit 3-4 muscle groups in a single movement. For leg day I may do Turkish get ups. That move alone works abs, shoulders, glutes, calves, quads and hamstrings. Essentially, even when focusing on a couple muscle groups you inevitably work additional muscles. Again efficiency and increased output. I also think kettlebells simulate athletic movement more so than barbells/dumbbells/machines. Now as far as weaknesses of kettlebells... form is really important and coaching is not as accessible as what you find for traditional lifting. Also, using shoulders as an example, traditional lifting is easier to target and shape specific muscle heads where a kettlebell targets the delts more broadly. Lastly, being kettlebells work the obliques A LOT, if you are trying to keep a small waste it will be difficult. THOUGHTS?