https://pmc.ncbi.nlm.nih.gov/articles/PMC11920532/ https://pubmed.ncbi.nlm.nih.gov/38190022/
Some of the broader claims like offering "many health benefits of longer workouts" or significant "strength" gains might be a bit ahead of what the current research consistently shows for these short bouts, especially when compared to traditional, longer exercise programs where, for instance, evidence for maximal strength gains is stronger , or where studies on snacks show more "modest" effects for some outcomes.
Regulators in the EU and Apple's App Review team are increasingly focused on the accuracy of health and wellness claims. To build more trust and avoid potential flags, it could be beneficial for you to refine the messaging to be more specific about the well-supported benefits, like convenience, breaking up sitting , and improvements in certain cardiometabolic markers for inactive folks, while being more nuanced about direct comparisons to comprehensive, longer workouts.
Highlighting the time efficiency and accessibility without overpromising on the extent of all health outcomes should be a more solid path for long-term success and credibility.
You will also likely run into legal problems, if you offer the same kind of exercises without taking age, chronic, and pre-existing conditions into the equation of what exercises to offer and do not offer a clear warning for these kind of users, that they should consult a doctor before using the app, what exercises might be appropriate for them and which are not.
Best of luck with the app!