Jem (and Michael if reading),
Congrats on giving this a shot. As a clinical trialist in a former life, am all too familiar with the difficulties of studying humans. A few comments / suggestions after reading the summary. Apologies if the questions are answered in other areas but am not following the socials.
The dropout rate, or perhaps differently termed, the non-initiator rate post sign-up, is very large. It looks like at least half of the signed up individuals simply disappeared? It would be worth trying to contact those folks to find out what happened. You guys likely have tried, but if not, perhaps provide an anonymous way for non-initiators to tell you why they didn’t start. It’s going to be a combination of best intentions not panning out, life intervened, protocol too hard, injury, etc. But knowing the answer rather than guessing, might help with future design.
Am wondering if non-initiation could be partially age related? e.g. perhaps a study of older individuals (45-65 or something) might provide a more stable or comitted cohort. Was there an IRB/ethics reason for capping age at 45, or was that a study specific decision to try and limit variability? If the IRB would permit it, and you guys are up for study #2, give it a shot with an older group and see what happens! (TL;DR Kids are unreliable and retired people have more time to do things like crowd sourced physiology studies).
Non-centralized trials, site independent trials, other flavors of studying people without requiring a ton of site visits, are a hot topic in drug development (and other forms of medical research). While drug development is not ex phys, if you do additional studies in the future, would suggest reaching out to some of the companies with growing expertise in the non-centralized study arena.
Human touch matters. Designing in interaction with a study coordinator or PI before starting and during the study for updates could be useful. One of the things we hear from patients in drug studies is they want to know more about what is happening. Blinding is critical for those studies as is avoiding bias and other issues. But your study is not going to a health authority, and you need completers foremost, so consider that engagement and completing is critical and think of ways to enable and encourage.
While pure altruism is great, incentivizing is even more great (LOL). Consider offering something of extremely low monetary value but extremely high “swag” factor to participants for initiating and completing. For example, a T-Shirt at the end for folks who initiate, complete the tests and complete an end of study questionnaire. A reasonable IRB should permit that type of thing and it wouldn’t be hard to find a sponsor for the reward.
There are other ways to approach the reward and engagement topic that doesn’t require any physical object. Will save those thoughts for another day though as this is getting long already.
For cyclists, I think the original question posed is important, and it would be great to see some guidance. Null hypothesis is that any six week VO2max block in a reasonably trained person will yield a similar benefit. But wouldn’t it be fun to have actual data of say 30/15 vs 6x3 vs The Empirical cycling Vo2max block are similar or actually different? With data collection including (a) completion/compliance difficulty (eg the best block ever created is useless if riders can’t/won’t complete the training block) and relative benefit on the measure of interest (VO2max surrogate like a 5 min test, wPeak, etc). You don’t need 100’s of subjects to do this, you need maybe 50-75 motivated subjects who will complete the study. Depends where you set alpha and what you assume for effect size.
Tl;DR - You guys are definitely onto something decent here. It might be that random crowd sourcing is not effective and need to do some preselection to find subjects more likely to complete.
I hope you’ll give it another try.
Good luck and best success in your studies and academic careers.
-Darth (LOL, have to preserve the anonymity but Jem has my contact info from a prior PM discussion)