Who doesn’t know this scenario. You are supposed to do an easy recovery run that becomes faster and faster because you are motivated and are feeling good or because you don’t want to be overtaken by that other guy. Did you know that running just a bit faster than you are supposed to can destroy your training program without you or your trainer realizing it? You were just sucked into the black hole of training.
What science says
Stephen Seiler, an american sport scientist at the Norwegian university of Adger in Kristianstad did research on this phenomenon in 2007 and gave it the name ‘training in the black hole”. The black hole has a nice training intensity and sucks your training into it. Your easy runs become a bit faster and the hurtful high intensity intervals become a bit less intense. You can probably see already what happens. You don’t train the one or the other intensity you are supposed to. Training on recovery days becomes just a bit too intense to give your best on high intensity training days.
For non professionals training in the black hole might be somewhat ok. You go for a 30-60 minute run and you run a bit faster than you should. Until your next training two days might pass which is enough time for a full recovery. The intensity will be high enough for adaptions. For serious training it is however essential to train in low and high intensity zones and not in the black hole.
The Black hole in elite sports
The reason for Seiler to research the phenomenon of the black hole was an experience with Olaf Tufte a Norwegian elite rower. After a third place at the world championships in 2002 he had just mediocre results in races the year after. It was a mystery what happed especially as his training schedules did not change. It turned out his new boat that he got after the championships had to do with it. The cool new boat gave him the extra motivation to go just a bit faster than normally on his recovery days. This additional intensity was enough to sabotage his regeneration and his results.
If the regeneration becomes the limiting factor of your training the black hole is poison that needs to be avoided.