In most countries, nightclubs and large gatherings are still banned and in many places, gyms are still closed. Even if gyms are open, there are usually time restrictions and less overall equipment available due to sanitation.
Because there is currently not a vaccine or significant reduction in cases, the COVID-19 situation rages on and wether or not you should bulk, cut, or maintain is still relevant.
When to bulk
Unless, you had previously planned on using this time to bulk up and put on muscle, I would recommend against a bulk during lockdown.
This is because, while it may be easy to eat in a caloric surplus, it most likely will be harder to put on muscle due to less heavy lifting able to be done.
If you have the same amount of equipment you had access to before lockdown, then by all means continue to bulk or train how you would have but for most people, now is not the optimal time to bulk.
The objective when bulking is to put on as much muscle as possible while not gaining too much fat. Since lockdown means that you can’t lift as intensely and with as many available exercises as before, you are more likely to put on fat while not gaining enough muscle mass to validate the extra calories.
Also, lockdown for a lot of people means that overall activity levels are lower since more time is spent at home. This means that for many, maintenance calories may need to be re-adjusted and lowered since the same amount of steps aren’t being taken per day. This also means that you are more likely to put on fat due to a more sedentary lifestyle so a caloric surplus on top of that is not optimal.
If you do bulk, make sure you will be hitting the muscles hard enough for growth and that you have a well-designed plan for how you are going to gain lean muscle mass.
Similar to bulking, if you were planning on cutting during this time already and have access to all of, or nearly of, the same equipment you had before, then go ahead and cut.
However, as with bulking, maintaining muscle mass becomes more difficult if you are not able to lift heavy weights and stimulate the muscle effectively.
The risk with cutting is that if you do not properly stimulate the muscle during a cut in lockdown, more muscle mass will be lost than it would have if you were training with heavy weights and equipment at a gym.
Due to this, the cut is less likely to be ideal and is better saved for next summer or spring when there are more options for training and the pandemic is less prevalent.
If you are sure that you want to cut, it is very important that you are stimulating the muscle enough for the body to burn fat instead of lean mass. I’d suggest owning a pull-up bar, resistance bands, sliders, and a medicine ball if you are trying to set up a cheap home gym. If your budget is larger I’d suggest additionally purchasing a bench and set of dumbbells.
Maintain if your training is limited by the equipment you have available.
Since both cutting and bulking are best suited for periods of time when you have access to heavy weights and machines, it is ideal to maintain your weight and muscle.
Also, since your activity level is most likely lower than before quarantine, your maintenance calories are going to be lower unless you are making up the steps. To maintain your muscle mass a very slight caloric surplus is helpful, like 20-50 calories, so just keeping your previous maintenance calories should be optimal since it is most likely now slightly higher than your actual maintenance.
To maintain your muscle and weight, focus on bodyweight exercises for the large muscle groups and use resistance such as bands, dumbbells, medicine balls etc for isolating the smaller muscle groups like arms and calves.
This will be sufficient to retain most of your muscle mass and ward off fat. Attempting to go on a large bulk or major deficit in calories is not going to give the same results as it would if gyms were fully open and accessible so it’s better to keep your muscle and fat levels until you can take advantage of a more standard lifting routine.
To briefly make the key points, bulk and cut if you were planning to anyway and have enough equipment to stimulate the muscle effectively. Since your activity is lower, keep in mind that a caloric surplus might require less calories now than before lockdown since generally less steps are being taken every day. Also cutting will be more difficult unless you have access to the same equipment you used before COVID-19 since it will be hard to keep muscle if it is not being stimulated fully.
Maintaining is the optimal phase to be in and will allow you to continue hitting your lifting goals once gyms reopen fully because you won’t have lost a lot of muscle or gained more than ideal levels of fat.