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Comparison of Strength Adaptation Responses Among Individuals with Different Muscle Fiber Type Profiles
Enes Beltekin1, Yunus Berk2, İhsan Kuyulu3
1Department of Sports Management, Faculty of Sport Sciences, Bingol University, 12000 Bingol, Türkiye.
Medicina (Kaunas, Lithuania)
|June 26, 2026
Summary
Muscle fiber type influences strength gains from resistance training. Type II fibers show the greatest strength increase, while Type I fibers show the least, highlighting the need for personalized training programs.
Area of Science:
- Exercise Physiology
- Sports Science
- Human Performance
Background:
- Muscle fiber type distribution significantly impacts hypertrophy and strength gains.
- Varied training adaptations among individuals suggest a role for muscle fiber type in response to resistance training.
Purpose of the Study:
- To comparatively analyze strength development in athletes with different muscle fiber types (Type I, Type II, Mixed) after a standardized resistance training program.
Main Methods:
- Quasi-experimental, single-group pre-test-post-test design with 48 male athletes (19-26 years).
- Muscle fiber types were indirectly estimated via 80% one-repetition maximum (1RM) bench press performance.
- A 6-week resistance training program (3 days/week, 80% 1RM, 8-12 reps) was administered.
Main Results:
- Statistically significant strength increases were observed across all muscle fiber type groups from pre-test to post-test.
- Individuals with Type II muscle fibers exhibited the highest percentage improvement in strength.
- Individuals with Type I muscle fibers showed the lowest percentage improvement in strength.
Conclusions:
- Resistance training enhances strength across all muscle fiber types, but the magnitude of improvement varies.
- Training program personalization based on individual muscle fiber type characteristics is crucial for optimizing strength development.
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