No, this isn't yet another of those million posts you read on the Internet about "my martial art is the best thing invented since breathing and all of you other pusillanimous pukes are my rightful prey and most bow down before me, moo-ha ha ha !"
In fact, something I have been thinking about for a while is the benefits and drawbacks of cross-training. This has been in the back of my mind for years, ever since one tournament when I saw a pretty good young black belt get slammed with uchimata.
A lot of times wrestlers beat judo players. The truth is that there are a lot more wrestlers in this country and wrestling coaches tend to run a lot more physically strenuous practices than most judo clubs do. This isn't uniformly true, but it's true of most judo and jiu-jitsu clubs and if you think differently, I recommend you get out of your little bubble and go watch some wrestling practices. PLEASE don't tell me how your club trains harder than everyone - I have heard that from so many instructors, it's just boring, not to mention impossible. There can't be ten jiu-jitsu schools in your city that train harder than every other school in the city. Nine of you guys are fooling yourselves.
My friend, Steve Scott, says in one of his book (I think it is Coaching on the Mat) that you should teach them like judo players but train them like wrestlers. I meant what I said literally. If you have never wrestled, or it's been twenty years (memories fade), I strongly recommend you drop by your local university and watch wrestling practice. It IS physically harder than most martial arts practices.
There are some excellent moves from wrestling that can help anyone's matwork. I'm always amazed when I meet a judo player who doesn't know how to do a half-nelson turnover. The link shows a half-nelson being demonstrated by Los Angeles Trade Tech Community College instructor, Steve Seck, who was a very successful high school wrestler before going on to make the U.S. Olympic judo team.
So... benefits of wrestling for judo and jiu-jitsu players - better physical conditioning, pick up mat moves that might not be as familiar or emphasized as much as they should be. BUT .... there can be too much of a good thing...
When cross-training is too much of a good thing
Going back to our young black belt investigating the number of lights in the ceiling - he hadn't been to judo for a while because it was wrestling season and he was on the team at his school. He came back to judo in much better physical condition. The only problem is that in wrestling no one ever gets a high grip on your gi because you're not wearing one. The third match in the tournament, someone got a grip on this young man, pulled down, and when he started to come back up, the opponent stepped in and slammed him. This was a good judo player and I am pretty sure if he had been coming to practice regularly the match would have come out differently. He had lost some of the reflex of protecting people from grabbing his gi because he didn't have to worry about it.
I'm always an advocate of going to other sports IN ADDITION to your main event, not judo practice instead of wrestling, jiu-jitsu instead of judo, or vice-versa. The most obvious difference wrestling has from jiu-jitsu and judo is there is no gi, so there is less fighting for a grip.
There are other "differences that make a difference". Of course, a really good judo or jiu-jitsu player loves fighting someone who gets in a wrestler's position on the mat, because they have their head up to keep from being turned over easily - which makes it harder to do a half-nelson but really easy to loop the gi under and choke them. They keep their arms too straight and are almost inviting armbars. In judo, wrestlers often win in the novice divisions where armbars, and sometimes chokes, are not allowed, but once they move into brown and black belt divisions a judo player will take them out. Of course, jiu-jitsu allows chokes and armbars from the very beginning.
From that last sentence, you might think it's easier for a wrestler to win at judo than jiu-jitsu. Not necessarily, especially not with the new rule changes. It is now (with limited exceptions) against the rules to grab the leg in Olympic judo, so a single-leg take down, double-leg take down and many other wrestling throws are now illegal in judo. They are, however, still legal in jiu-jitsu (and freestyle judo). So, a technique that would get a wrestler a penalty in judo will get him points in jiu-jitsu.
The obvious point is that there are differences in the rules and if you are doing too much cross-training, you get into the habit of playing by a different set of rules - a lesson our young black belt learned the hard way.