Yeah not sure dude, never did any cycling or swimming and stuff ever, but yeah ppl say that's all very good too.
Am no expert or anything, just tend do what the trainer says and don't think about it. But yeah in recent years there's been loads of sciencey people and various athletes coming out saying running doesn't work, running is bad for you, overtraining etc etc. But... cannot reconcile that with personal training experience. When running a lot and regularly, everything else feels easier and smoother in training. 10k every morning, and another 4k later in afternoon.
When first starting out? Felt nothing but hatred for running. Thinking, "Wait a sec, if I knew how to run I wouldn't have learned how to fight, wtf yo...". Just kept my mouth shut and did it anyway cuz the trainer was scary and didn't wanna get in trouble. Then, after first 3 years, started to love it. Like, really really really fucking love running, and will keep doing it until the old man days.
This is just one guy's 2 cents, but now it feels like the biggest benefit isn't even the cardio. Obviously that's super important, not denying it's good for that. But even better than the endurance it gives, it improves my concentration throughout the day and makes you really calm and balanced mentally.
Plus it feels like the body kick and knee are stronger with regular running, but dunno if that's a placebo effect or not. But shit, even if it is, I'll take it.