Yet you can see that with full recovery the athlete is ‘improved’ to 110% after a week or so. Perhaps a long time to wait; but improved nevertheless.
So, in fact, the optimal session is somewhere around the L3/L4 boundary – perhaps more likely in L3 than L4. In this diagram it is the circled area. Ah!!! The science of a pretty diagram, who needs pesky numbers and levels of confidence !!
This is looking at percentages of your threshold power (FTP = CP60). Which is the increase in your 60 minute flat out performance (you can think of it as your 60 minute run distance or your FTP if you are a cyclist – they amount to effectively the same thing). For anything/any race over 30 minutes or so threshold power is critically important – basically whichever person’s is the highest should win. It’s very important for 5k too but a few other factors come in there as well. But for ANY triathlon or DUATHLON distance you WILL take more than 30 minutes to complete it, I think (well, actually, I’m pretty positive you’ll take more than 30 minutes!).
If you are looking at measuring improvement in your VO2max then, for most of you, I wouldn’t bother..try measuring it every week for 6 weeks and track the improvement in your VO2max (there will be virtually none). Focus on your FTP. Coincidentally your LTHR is probably one measure which many of you can maintain for an hour or more in a race. ie pretty similar to FTP. You can fairly accurately estimate FTP/LTHR from 20 minute efforts … ie a 5K race or CP20 bike test. Search this site or elsewhere for calculating FTP or LTHR. Anyway, I digress from sweetspot sessions.
So. If you fancy a sweetspot session just have a little sneaky look at this chart and it may well tell you your required effort level using one of the metrics you understand. eg 2x20mins with 5 RI @[RPE7/10, RPE14/20, 85%HRmax, 95% LTHR or 95%FTP and so on]. Do that twice a week; have one long session, have one super fast/short/VO2/interval session, do some weights/plyo/stretch/massage then you WILL improve week-on-week.
Be warned though. You could be getting into dangerous over-training territory. Look in my reviews for a review of BIOFORCEHRV – apps like that can help you fend off the dangers of over-training.