Research
Mixed
Tapering after intense training induces a 'Type IIx overshoot,' where fast-twitch fiber characteristics and power output increase beyond pre-training levels.
If you are an endurance athlete, do not fear reducing your training volume before a major event. A proper taper can lead to an 'overshoot' in fast-twitch fiber power, helping you perform better in sprints or hills at the end of a race.
ModerateSupportsMEDIUM confidence
There appears to be a type IIx overshoot after a period of training and detraining, which corresponds with superior fiber velocity characteristics [30].
Why this rating
Based on specific studies (e.g., marathon tapers) and animal models; less generalizable than primary training effects.
Source
Muscle Fiber Type Transitions with Exercise Training: Shifting Perspectives
Daniel L. Plotkin et al. · Sports · 2021
DOI 10.3390/sports9090127
narrative_reviewCited 249×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Resistance, sprint, and power training induce a shift from fast-twitch IIx fibers to the fast-twitch IIa phenotype, with minimal change in pure type I fibers.Good
- Endurance training induces a shift toward a more oxidative phenotype, characterized by an increase in Type I fibers and a decrease in Type IIa fibers.Good
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