There are a lot of great trainers on YouTube. They show you exercises and thus motivate you to participate. When the fitness studios were closed in Germany during the pandemic, I started doing small units with YouTube videos every day.
If I expect models to take care of their bodies, I need to do the same. After all, as a photographer you have to have a good endurance for long shooting days. Sometimes you're lying on the floor like a dead beetle on its back and you need your abdominal muscles. Or you simply need to carry heavy equipment from A to B.
Meanwhile I have a long playlist of abs, legs, torso and stretching videos. For one year, I do a workout out of this every single day. Even if the units are only 5 to 15 minutes long, it takes a lot of discipline.
Here are two of my favorite workout sessions.
5 minute abs with Sami Clarke
Training abs is always hard. But these abdominal exercises are effective. And that feels really good after training.
10 minute legs with Brandy Gordon
Leg training is so important because it shapes the buttocks nicely. Brandy Gordon's video has hardly any views (I am probably responsible for half of them), but the training is really damn good. The sound is not perfect, but her voice is doubly sympathetic. And her training is one of the best videos for legs out there.