I’m not familiar with Jiu-Jitsu specifically but I have trained in a few martial arts, Japanese and western, and they usually have routines you can practice on your own. Is the same not true for Jiu-jitsu?

With the bored sports, while you obviously couldn’t train your board skills, you could still keep working on those muscles and stamina at home through different training exercises.

I agree none of this is the same as going to your gym et al, but my point wasn’t that you could do identical training at home. It was that you could do something similar to at least keep yourself reasonably sharp.

Yeah there's probably some, the problem is motivation. I can go to a class and workout hard for hours, and not really notice. After a few minutes of running I'm ready to call it a day.

Same for surfing, keeping busy with a skateboard though. Paddle endurance is taking a hit.

If he's talking about Brazilian Jiu-Jitsu, then there's very little you can do on your own unfortunately. It all depends on having access to a training partner.

I just had a quick Google and found a bunch of training videos on YouTube for Brazilian Jiu-Jitsu, so it does seem possible. Having done a number of martial arts myself I do understand that having a partner does make a massive difference but I've never come across a martial art that doesn't have solo training exercises to enable individuals to practice when alone. Even the martial arts that you wouldn't expect could work solo (like fencing) still have solo training exercises.

Yes there are things you can do, but they're not very effective, especially if you've been training a while.

Focusing on general strength training, flexibility and improving your endurance is much better use of your time than doing these solo drills.