Do try this at home!

Among yoga practitioners there is the notion of a home practice. You might get to class once or twice a week, but ideally you practice at home every day, or -- more realistically -- on most days.

If you practice a martial art with solo katas (also known as sets, forms or patterns) -- such as karate or kung fu -- you can always practice those by yourself, but what about styles that rely primarily on partner practice: jiu-jitsu, judo, aikido etc.? Here are some ways you can practice at home:

1. Most styles have some solo elements: For example, in my jiu-jitsu classes most of the breakfalling exercises are performed individually (although as a group). Many of these require mats -- another obstacle to home practice -- but many do not. Try those ones at home. Benefits: These sorts of drills develop coordination and physical conditioning appropriate to the art.
2. Partner techniques can be practiced within an imaginary partner: You've practiced a technique class. Practice at home, but imagine your partner. In karate or kung fu the challenge is often to figure out the application of a solo form. In partner-based styles we can go the other way. You can practice against different-sized phantom opponents, invent combinations, etc. For my students I highly recommend practicing the eight movements of kuzushi in this way (video). Benefits: Improved fluency, strengthens the imagination, etc.
3. Partner techniques can be visualized without moving: This one borders on some forms of meditation, and can be practiced while standing, sitting in seiza, on the train, as a cure for insomnia. Visualize an entire technique, imagining the movements in as much detail as you can. Feldenkrais had a nice idea in his Awareness through Movement technique that we can steal: Practice an asymmetric technique several times in its right-handed version with an imaginary partner. Then do a few reps visualizing the left-handed version without moving. Benefits: Even stronger mental training. Improves your adaptability. Learn to transfer skills drilled on one side to the other with minimal physical practice.
4. Find the fundamental movements: Applications in the martial arts can be quite elaborate, but there are movements that come up over and over. By practicing with your imaginary partner these should become more and more apparent. Isolate them and practice them, visualizing the various applications. This kind of practice can start to look a bit like qigong. Benefits: Most of the above, plus gain deeper insight into your martial art.

Not quite what I mean, but impossible to resist:

Colin "Bomber" Harris wrestles himself

And furthermore ...

Making a go of this kind of home practice is a great step towards incorporating martial arts into the rest of your life. Doing a short session before work (or whatever) is a great way to start the day, and I personally try to run through (in my case) a hung kuen kung fu set a couple of times during my lunch break and again in the evening.

I'm not advocating hours and hours of daily solo practice, but rather 30 minutes to an hour, perhaps spread through the day. Not only is this a very physically healthy thing to do, it has meditative benefits, and will help you progress in your chosen martial art. It increases your "flying hours" and, if you properly engage your mind, questions should arise that can be answered the next time you go to class, through further practice (with a real partner).