Why is it that so many coaches and experienced riders swear by threshold training in zone 4 as the key to building sustainable power, yet theres a glaring lack of concrete, scientific evidence to support the claim that its any more effective than training in other zones?
Its always the same tired truisms and anecdotal evidence - its where the pros train, its the most efficient way to build FTP, its the only way to get faster - but wheres the actual data to back it up?
Is it just that its a comfortable, feel-good zone for most riders, or is there genuinely something magical about the 88-94% of max HR range that makes it superior to other zones for building power?
And what about the riders who dont respond to threshold training - are they just anomalies, or is there something more complex going on that were not accounting for?
Were constantly told that threshold training is the gold standard of power-building protocols, but what about the countless riders whove built impressive power and endurance through other means - are they just outliers, or is there something to be learned from their approaches?
Its time to stop spouting dogma and actually examine the evidence - or lack thereof - behind the cult of threshold training. So, lets get to it: whats the real science behind why threshold training in zone 4 is supposed to build sustainable power, and is it genuinely the best way to go about it?