Mixed
High-intensity interval training (HIT) consisting of 6-12 sessions of sustained exercise at 80% peak power output significantly improves 40 km cycling time-trial performance in well-trained athletes within 2-3 weeks, independent of changes in VO2max.
If you are already a well-trained endurance athlete, adding 6-12 sessions of high-intensity interval training (replacing about 15% of your usual volume) can significantly improve your race performance in just 2-3 weeks. Focus on riding at your current 'race pace' intensity for sustained bouts (e.g., 5 minutes) with short recovery, rather than just riding longer distances. This builds fatigue resistance and metabolic efficiency without needing to increase your maximum oxygen uptake.
Typically, cyclists improved their 40 km time-trial speed by 1.5-2.0 km h-1, which represented a 90-120 s improvement in their performance for that distance... most of the HIT-induced improvements in both peak power output (Fig. 2A) and 40 km time-trial performance (Fig. 2B) appear to be complete after only six HIT sessions.
Why this rating
The study uses a controlled intervention on a specific, homogeneous group (n=20 male competitive cyclists) with baseline testing, though it lacks a control group of non-HIT trained athletes.
Source
Training techniques to improve fatigue resistance and enhance endurance performance
John A. Hawley et al. · Journal of Sports Sciences · 1997
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