Sometimes life makes it hard to train. You get sick. Your kid gets sick. A major holiday comes along. You lose your job and need to save money on training for a while. You get injured. You're traveling. Your job schedule overlaps with your training schedule. Whatever the reason, "life happens", as they say, and you can't get into the gym. I tend to start jonesing for my jitsu fix after a couple of -days- without training, and I've had to deal with many times during my training when I've had to spend weeks without it. There are a couple of approaches one can take when this happens.
First, you can try to simply forget BJJ exists. This never really works, because in the back of your mind you know you're trying to forget something and though you can focus on other things, when thoughts inevitably DO return to BJJ, you feel worse than ever.
Another method of dealing with this problem is to practice in your mind. I've been reading a lot about and playing with mental imagery training recently. It's often called simply "visualization", but whatever you call it, the results are the same. Time and time again, studies show that it doesn't seem to matter how you develop and reinforce the neural pathways created with perceptual learning, the results are very close to the same whether or not you physically perform a task, or just imagine yourself performing it.
In the mid-20th century, the USSR simply dominated the world gymnastics scene and nobody really understood how. Other athletes undoubtedly practiced just as hard as their Soviet counterparts, but when the Soviets were on the mat, it was simply amazing. Find any video of Larisa Latynina from that era (winner of over 18 Olympic medals including 9 gold...and even 1 silver while pregnant) and you'll see why she, Nikolai Andrianov, Boris Shakhin, and their teammates were so adored. Their routines were perfect. It wasn't until nearly 30 years later that we learned how they were doing it and the extent of the Soviet use of mental imagery training. In the 1980s, psychologists began studying this phenomenon.
In one famous visualization study from the University of Chicago, three groups of basketball players each were tested on their free throw percentages and then told to practice (or not) in one of three ways: the first group would practice for one hour a day standing on the free throw line throwing basketballs, the second would go to the gym, but would simply visualize practicing free throws for an hour a day, and the third group (the control) would not practice free throws at all. At the end of the study, they were tested again. Of course, the group that didn't practice at all showed no improvement and those that physically practiced were now better at free throws (by 24%). What was really surprising was that the group who had just visualized throwing free throws were also much better than they'd been before the study: 23% better in fact. Take a moment to let that sink in. The athletes who hadn't even attempted a real free throw showed almost as much improvement as the ones that actually practiced doing it for an hour a day. Again, study after study confirms that the neural pathways related to perceptual learning can be created and reinforced by simply imagining the experience.
How do you use this? Well, here's what I do. I spend about 10-20 minutes each night mentally practicing one BJJ technique. I close my eyes and focus on every detail from hand and food placement to balance and stance and just imagine myself doing it perfectly every time. I've only really been working on a few techniques up to this point, but I can tell already it definitely makes those techniques come to mind much easier during live rolling. What's more, I can, as Steffan Kesting has recommended, "sharpen my blade in secret", meaning that I can work on a technique that I don't want to practice live with my peers until I've got it committed to memory and feel comfortable with it, rather than letting them get better at defending it in parallel to my learning it.
BJJ + Visualization = Success
Try it! :)