As boring as it may sound, the best start in your situation is to get fit. I mean it. Books and online videos overstate the importance of technique as if it alone was the answer to everything – it isn’t. All martial arts rely on strong support and postural muscles as a fulcrum, whether for throws, blocks, punches, or kicks, so I’d recommend bodyweight exercises (plank, crunches, etc.) instead gym weight machines which isolate the arm and leg muscles with enganging those support and postural muscles. Brazilian jujitsu guys swear by
, it’s one of the best bodyweight systems there is.
I wouldn’t recommend any formal systems like karate and similar Eastern striking arts, there’s too much room for error here if you don’t have an instructor to correct your mistakes, mistakes you won’t even notice as a beginner, like tilting your pelvis backwards instead of forwards which will make you fold like a concertina the moment you hit a solid object. If you’re able to enlist the help of a friend for those
pool noodle drills I wrote about, this can be a more reliable way to learn blocks instead of repeating the same old formal karate blocks for years. Incidentally, a good idea would be to acquire a boxing heavy bag or fashion yourself a
(
) – in this way, you’ll acquire a solid and firm stance instinctively instead of practicing formal stances for years and years. It’s how boxers learn to punch effectively, learning by doing instead of following theoretical instructions.
Throws, locks, and chokes probably can’t be learned without a partner but that’s outside my area of expertise.