Why do so many coaches and training programs still prescribe large amounts of zone 4 training, despite the overwhelming evidence suggesting that it can lead to burnout and decreased performance in the long term? It seems counterintuitive that athletes would voluntarily subject themselves to prolonged periods of high-intensity training, only to risk overreaching and requiring extended periods of recovery.
Is it possible that the benefits of zone 4 training, such as increased cardiovascular fitness and improved muscular endurance, are being overstated, while the risks, including increased cortisol production and decreased immune function, are being downplayed? Furthermore, are the performance gains achieved through zone 4 training truly sustainable, or do they come at the expense of long-term health and well-being?
Its also worth considering that the traditional zone-based training model, which emphasizes spending large amounts of time in zone 4, may not be the most effective or efficient way to improve performance. Alternative approaches, such as polarized training, which emphasizes spending more time at low intensities and less time at high intensities, may be more effective at promoting long-term progress and reducing the risk of burnout.
What are the arguments in favor of zone 4 training, and how do coaches and athletes balance the benefits against the risks? Are there any alternative approaches that have been shown to be more effective at promoting long-term progress and reducing the risk of burnout?