Effects of strength training and immobilization on human muscle fibres

Seven healthy male subjects were studied under control conditions and following 5–6 months of heavy resistance training and 5–6 weeks of immobilization in elbow casts. Cross-sectional fibre areas and nuclei-to-fibre ratios were calculated from cryostat sections of needle biopsies taken from triceps brachii. Training resulted in a 98% increase in maximal elbow extension strength as measured by a Cybex dynamometer, while immobilization resulted …