Summary of a study looking at the percentage of different types of muscle fibers in female and male elite Olympic weightlifters.
21 elite weightlifters (15 females, 6 males) with at least 2 years of national competition experience (USA).
- WCF - 6 world caliber females (Olympic or World team members)
- NCF - 9 national caliber females (top 5 finishers at the American Open finals)
- NCM - 6 national caliber males (top 5 finishers at the American Open finals)
Cross-sectional study where 2-96 hours after competing in the 2017 International Weightlifting Federation World Championships or the USA Weightlifting American Open Finals biopsies were taken.
- MHC content (myosin heavy chain content) via SF technique from resting vastus lateralis muscle biopsy
- the results obtained by HG technique are omitted in this summary, go to the original article (link at the bottom) if you want to learn about these.
- 102 ± 3 fibers per athlete were isolated
- WCF were competing in sports for about 5 years longer than NCF and NCM, they were also older than NCF
Muscle fibre type analysis:
groups were similar in the distribution of different fibre types, but 90% of IIa/IIx fibers were found in heavyweight lifters. This may suggest the relationship between body mass and frequency of MHC IIa/IIx type fibers.
MHC IIa fiber type concentration in athletes was very high:
- WCF - 71%
- NCF - 67%
- NCM - 63%
- for comparison, MHC IIa % was reported at 30% in national level male soccer players, 52% in males training sprinting, 39% in natinal caliber male bodybuilders.
when results for all lifters were combined:
- 23 ± 9% of fibres were I type
- 5 ± 3% of I/IIa
- 67 ± 13% of IIa
- 6 ± 10% of IIa/IIx
- no IIx or I/IIa/IIx fibers
Take home message
Serrano N, Colenso-Semple LM, Lazauskus KK, Siu JW, Bagley JR, Lockie RG, Costa PB, Galpin AJ. Extraordinary fast-twitch fiber abundance in elite weightlifters. PloS one. 2019 Mar 27;14(3):e0207975.