In the era of COVID-19, partner training is a bad idea. You do not want to spend extended periods of time breathing heavily in the same space, and especially not indoors. Grappling is particularly risky.
Many martial arts already include social-distancing-ready methods in their standard training that can fill your social-distancing training hours. Many of these methods are not suitable for partner training, so now is the ideal time to get full use of them. They do not substitute for the fighting skills you acquire sparring and partner training, but those are not available right now.
I will avoid evaluating styles and instead point out elements that can/should be practiced with social distancing. Lots of styles have these elements, so I will point out a few examples and leave evaluation to you.
Forms training is the foundation of many martial arts body development. Forms usually combine elements of speed, balance, leg strength and flexibility, coordination, mental focus, and prototypes of martial techniques together in one package. Styles using forms include kung fu (in all its flavors), karate, and tae kwon do.
Depending on your social distancing risk tolerance, you may be comfortable having a masked instructor stop you periodically and make physically adjust your body. The time they need to be near you is short and they can otherwise be at a distance. Otherwise, the instructor can demonstrate at a distance and provide feedback. Outdoor forms practice would be preferable to indoor.
The general problem with forms is that styles can have them without being able to fight. But you should be able to imagine that someone able to fight can give you sequences of movements to work on, and those sequences can be called forms.
Basics - Footwork as an example
Most people are not willing to invest the time in learning "basics" that they could because sparring and other exercises are more fun. Now is the perfect time to focus basics you can practice alone because your partners are not available. This analysis is based on my study of bagua, but I expect you will find it applies to boxing, kickboxing, MMA, etc.
Let's assume your style has a fighting stance that you use. Enter your fighting stance, then take a step forward.
- Are you immediately in your fighting stance again? Or is your spacing off?
- Are you immediately balanced, or do you need a moment to regain your balance?
- Are you on balance as you move? If someone were to grab your belt (something around your waist) and then you step, would you be leaning to move forward?
- Do your legs drive your movement when you step? Or do you fall into your step?
- Is your step fast, or is this a great time for a sparring partner to sweep your feet?
- Now that you have tried to fix several different things, are the earlier ones still fixed?
OK, so now that you have fixed all of these things, you can add steps in other directions. You probably at least want to also step angled to the left, step angled to the right, and backwards possibly also to the side. Presumably you started facing an opponent, so as you move to the side angles, you will want to turn towards your opponent.
- Check all of the above items again for each direction
- Now that you are turning as you are stepping, are you leaning as if banking into a turn on a bicycle? Do not lean because this puts you off balance.
Now you can step in multiple directions.
- Can you react from your fighting stance to move in each direction equally well? If not, why is this your fighting stance?
- Can you move in any direction at reflex fighting speed, or do you stop to think about it?
- What happens when you practice stepping in a field where the ground is not perfectly flat? Are you tripping over the little divots animals have dug?
You can practice all the footwork alone, although it can be helpful to have partners provide moving resistance or other feedback. It takes a surprisingly long time to learn footwork, and honestly the training can become a slog, but really at some point the footwork becomes advanced and not basic.
We have not even started on the hands yet, but this is enough.