What about cardio?
Conversations about Hojo Undo usually center around strength training. This happens for a few reasons. First, cardio is not karate specific. Second, Hojo Undo is mostly championed by Naha-Te styles; which are inherently more strength focused than Shuri-Te. Third, the meat-heads who actively looks for new heavy things to lift are rarely as proactive with cardio.
Actually, I'm curious about that last point. Does anyone out there actually like both strength training and cardio? Personally, I only do strength training because I recognize that it's really important. I run because I like it. I find it relaxing. My instructor on the other hand always said that he took up karate so he never had to run again. He would wax lyrical about weight lifting, though. I've never met anyone who did both for fun.
Anyway, back to cardio. The first question is: is it important? It is absolutely important for life. Cardio-vascular health is the most important kind of health. It's less important for martial arts, however. Assuming you're not focused primarily on sport fighting, and if you're doing karate then chances are you're not, then you're mostly worried about the quicker and dirtier world of defensive fighting. "Real" fights are rarely long enough to require much cardio-vascular endurance; at least not more than you will develop from regular practice of things like kata and basics. If you can get through your normal class then you can get through a fight. It certainly wouldn't hurt to have a bigger gas tank, though. Fights are very stressful things, and having one less week point is always good. Even as merely a psychological advantage it can be helpful. Still, strength is definitely more useful than cardio in a self-defense situation.
Outside of fighting the next concern is training. Anything that helps you train longer, safer, or more efficiently is going to translate to more skill in a fight. This is where I find cardio to be the most useful. There was a huge difference in my in-class effectiveness after I started doing dedicated cardio training. Being generally less tired I was able to focus more on the actual learning. In drills with other students I was able to maintain good form for longer because I wasn't distracted my screaming lungs and muscles. Naturally, it was a big help in sparring too. As much as "real" fighting does not require lots of endurance sparring, sport fighting, does. As it turns out, fighting is much easier when you can breathe. Comment below if I just blew your mind. I was more effective, but I was also safer. I made less mistakes because I was less tired. I could capitalize on my opponents' mistakes because my technique was better. My technique was better because my practice was better. My practice was better because I was less tired. I was even less nervous because I knew there was one less thing to go wrong.
So, if cardio is useful after all what kind of cardio is best? Running is the most traditional, and it has a lot to recommend it. Not only is running good cardio training, but it strengthens the legs which are very important for karate. I got a huge boost to my sheiko-dachi endurance when I started running. Also, it's boring. Some people would consider that a downside, but it's one of my favorite parts. The practice of powering through pain with no distractions over a significant length of time has been very helpful to me. A fun fact about distance-running: humans can run further in one stretch than any other animal. We're not the fastest by any means, but we can go the furthest. Ultra-marathoners can run 100 miles in a 24 hour period. One of the oldest forms of hunting, which is still practiced in some parts of Africa, is to separate an animal and simply chase it until it can't run any longer. I like to remember that the next time I do a 5K; that I'm only asking for 3% of my potential as a human.
As big a fan as I am of running I do acknowledge that is does have a few problems; specifically three problems. First, many people absolutely hate it and won't do it under any circumstances. Maybe that's a problem with the people more than the exercise, but the result is the same. Second, some people genuinely can't run. There's nothing inherently harmful in the act of running. Our bodies are in fact designed to be excellent at it, but some medical conditions and injuries can make it difficult. Third, it does take time. Because we're so good at it it takes longer to get a good workout. That problem gets even worse as you do it more. If time is a limiting factor for you it may be difficult to devote enough time to your runs to see good results.
So what else can you do for cardio training? There are any number of options. I can't possibly describe them all, but I can give a few good options that should cover the most number of people.
Rowing is a very popular and effective form of cardio. It's low impact and it involves the biceps: see prior comments about meat-heads. Rowing works the entire body instead of just the legs, and can help with total body coordination. It's also easier to add resistance to your rowing to add a strength component. It does require some equipment, though. You need access to a rowing machine/boat and lake.
Swimming has much the same benefits of rowing, and the same downsides.
Getting away from the more traditional forms of cardio there's HIIT. HIIT stands for High Intensity Interval Training. High Intensity is exercise code for heavy weights. There are many forms, but the essence of all of them is to move heavy stuff as quickly as you can for as long as you can. Since the intensity is so high "as long as you can" won't be very long, and that can make HIIT friendlier for people unable to devote 30 minutes to an hour to cardio. Bodybuilders often use HIIT as a way to burn more calories without losing their "gainz." My favorite HIIT is to string hojo undo exercises together to make a circuit. (Get your own quality hojo undo equipment atwww.modernhojoundo.com.)
Love it or hate it we can all agree that regular cardio training makes us more efficient martial artists. As with anything the key is to find a method that you enjoy and do it regularly. The cardio you do is always better than the "best" cardio that you don't do.
Did I miss your favorite cardio? Let us all know in the comments.