Whats the logic behind using a dumb trainer over other low-impact cardio options for injury recovery, specifically for cyclists who need to maintain some level of cardiovascular fitness without putting excessive stress on the injured area? Is it truly more effective than using an elliptical trainer or rowing machine, or are we just defaulting to dumb trainers because theyre perceived as more cycling-specific? Are there any studies that actually compare the benefits of different low-impact cardio options for cyclists recovering from injury, or are we just relying on anecdotal evidence and hearsay?