Of course, running can give you incredible cardio : if you do a combination of sprinting and aerobic running, you might be ok with going the distance.
But I personally think swimming can give you supreme cardio too, as it ramps up your heart rate quite as much.
Of course, you ain't getting the benefits of standing upright or strenghtening your bones, but on the other hand you don't injure yourself and work upper body strength and flexibility.
Of course, you have to do it correctly. If you replace solid 5 miles runs and hill sprints by 10 sloppy laps, it ain't gonna work for you. But if you do some long swims with some accelerations inbetween, and end up your workout with a 10*50m butterfly, it can be great.
You gonna tell me that fighters who don't run because of fucked up knees tend to have shitty cardio (Conor, Rua etc.) I can name you as much fighters that don't run (like Usman) who have great cardio.
I think it has more to do with genetics: some guys (like Conor) are most fast twitch type of athletes (which give them this insane Ko power) while others are more slow twitch athletes (and thus are often pillow fisted).
From my own experience, I used to be a pretty good runner as a teenager/young adult (had a 35 min 10k).
This cardio carried well to mma and bjj, where I was a Diaz bros type of fighter, simply never getting tired... combat sports felt so easy cardiowise compared to running. Unfortunately, I had to stop running because of multiple knee injuries. So I replaced the 4 running sessions a week by 4 swimming sessions, and bought a heavy bag, in order to do 15 min dutch drills every day (like 1-2 left kick, non stop for 2 minutes)
In the first place I was completely despaired and thought I had lost my best option to have good cardio. But, now, after 10 years of not running AT ALL, I am glad this happened to me. My cardio is as good as it was (maybe slightly diminished because it's harder to get to those 190 bpm's by swimming, but it's very very infinitesimal), I have way more strength in the upper body, great shoulder flexibility (which helps to surive kimuras...), and feel injury free and loose. Moreover, the dutch drills gave me mma specific muscular endurance, which running wouldn't have given me.
To sum this up, there are many ways to work on cardio. Dutch drills combined with swimming are my favourite ones, but the rowing machine and bike are other good ones. Of course, I would like to squeeze in some hill sprints or a good 5k from time to time, because running remains a great way to work on cardio, but it isn't requisite.
Just my thoughts, what do you think about it?
