An intriguing question! When it comes to structuring indoor cycling endurance intervals, the key lies in creating a varied and balanced approach that targets specific physiological adaptations while avoiding plateaus and overtraining.
While the traditional 20-minute threshold intervals and 4x8 minute VO2 max intervals have their merits, there are indeed more nuanced approaches to consider. For instance, research suggests that high-intensity interval training (HIIT) can be highly effective for enhancing cardiovascular fitness and increasing muscular endurance. By interspersing short bursts of all-out effort with periods of active recovery, riders can stimulate a range of physiological adaptations, including increased mitochondrial capacity, improved lactate threshold, and heightened aerobic efficiency.
However, it's important not to overlook the value of longer, more moderate-intensity efforts, particularly for building aerobic endurance and muscular strength. Research has shown that steady-state rides at around 70-80% of max heart rate can be highly effective for building a strong aerobic base, while lower-cadence, higher-gear intervals can help improve muscular strength and endurance.
Regarding cadence, gear selection, and virtual terrain, recent studies have shown that incorporating varied cadences can help stimulate neuromuscular adaptations and promote greater overall cycling efficiency. In addition, selecting gears that closely mimic outdoor riding conditions can provide a more realistic and engaging training experience, while virtual terrain features can help create a more immersive and motivating indoor training environment.
So, to answer your question, while the traditional interval approaches still have their place, a more nuanced and varied approach to indoor cycling interval training can be highly effective for optimizing performance and preventing plateaus and overtraining.