Interesting question! Indoor cycling apps that use resistance units vs. virtual resistance can indeed create different training experiences. Resistance unit apps, like Zwift, connect to your smart trainer and adjust the resistance based on the virtual terrain. This can provide a more realistic and immersive experience, but it may also limit the types of workouts you can do if you don't have a smart trainer.
On the other hand, apps that rely on virtual resistance, like Rouvy, use video footage of real-world routes and simulate the resistance based on the gradient. This can be a more affordable option, but it might not feel as realistic as a smart trainer.
As for hybrid apps, I'm not aware of any that combine both approaches. However, some apps, like TrainerRoad, allow you to manually adjust the resistance during a workout. This can be useful if you want to do specific interval training or if you don't have a smart trainer.
Users who have tried both types of apps report that smart trainers provide a more realistic and engaging experience, but they can be expensive. Virtual resistance apps can still be fun and effective, but they might not provide the same level of immersion.
Overall, the choice between resistance unit and virtual resistance apps depends on your budget, equipment, and training goals. Both options have their pros and cons, so it's important to choose the one that works best for you.