0000000000745914
AUTHOR
Alexander Cristea
Effects of combined strength and sprint training on regulation of muscle contraction at the whole-muscle and single-fibre levels in elite master sprinters
The aims of this study were to investigate the mechanisms underlying (1) the ageing-related motor handicap at the whole muscle, cellular, contractile protein and myonuclear levels; and (2) ageing-related differences in muscle adaptability.In vivo muscles function was studied in the knee extensors. Decreases were observed in isokinetic and isometric torque outputs in old age in the sedentary men and women and elite master sprinters. A 20-week long specific sprint and resistance training successfully improved the maximal isometric force and rate of force development in a subgroup of master sprinters.In vitro measurements were performed in muscle biopsies from the vastus lateralis muscle. Immu…
Aging, muscle fiber type, and contractile function in sprint-trained athletes
Biopsy samples were taken from the vastus lateralis of 18- to 84-yr-old male sprinters ( n = 91). Fiber-type distribution, cross-sectional area, and myosin heavy chain (MHC) isoform content were identified using ATPase histochemistry and SDS-PAGE. Specific tension and maximum shortening velocity ( Vo) were determined in 144 single skinned fibers from younger (18–33 yr, n = 8) and older (53–77 yr, n = 9) runners. Force-time characteristics of the knee extensors were determined by using isometric contraction. The cross-sectional area of type I fibers was unchanged with age, whereas that of type II fibers was reduced ( P < 0.001). With age there was an increased MHC I ( P < 0.01) and re…