Human skeletal muscle myosin function at physiological and non‐physiological temperatures

Lionikas, Arimantas; Li, M; Larsson, Lars

doi:10.1111/j.1748-1716.2005.01516.x

Cited by 16 publications

(11 citation statements)

References 41 publications

(69 reference statements)

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“…In vitro motility studies after extraction of myosin from millimeter short muscle fiber segments from human percutaneous muscle biopsies have shown that the aging-related slowing at the single muscle fiber level is primarily caused by altered structural-functional properties of the motor protein myosin (33,34,42). Multiple slow MHC isoforms have been identified in skeletal muscle (14,18,35,47), and the possibility cannot be excluded that the slowing in old age is associated with an aging-related upregulation of an isoform not, or less, expressed in young individuals. However, there is to our knowledge no evidence of the expression of novel slow MHC isoforms in old age with migration properties similar to the ␤/slow (type I) MHC on SDS-PAGE.…”

Section: Discussionmentioning

confidence: 99%

Aging, muscle fiber type, and contractile function in sprint-trained athletes

Korhonen¹,

Cristea²,

Alén³

et al. 2006

Journal of Applied Physiology

251

222

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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 (V(o)) 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 reduced MHC IIx isoform content (P < 0.05) but no differences in MHC IIa. Specific tension of type I and IIa MHC fibers did not differ between younger and older subjects. V(o) of fibers expressing type I MHC was lower (P < 0.05) in older than in younger subjects, but there was no difference in V(o) of type IIa MHC fibers. An aging-related decline of maximal isometric force (P < 0.001) and normalized rate of force development (P < 0.05) of knee extensors was observed. Normalized rate of force development was positively associated with MHC II (P < 0.05). The sprint-trained athletes experienced the typical aging-related reduction in the size of fast fibers, a shift toward a slower MHC isoform profile, and a lower V(o) of type I MHC fibers, which played a role in the decline in explosive force production. However, the muscle characteristics were preserved at a high level in the oldest runners, underlining the favorable impact of sprint exercise on aging muscle.

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Section: Discussionmentioning

confidence: 99%

Aging, muscle fiber type, and contractile function in sprint-trained athletes

Korhonen¹,

Cristea²,

Alén³

et al. 2006

Journal of Applied Physiology

251

222

View full text Add to dashboard Cite

show abstract

“…Although alterations in contractile function at the whole muscle level are reflective of myofiber contractile behavior (41,45,48,51), it is difficult to directly compare values obtained in isolated muscle fibers with values obtained in vivo. In addition to the factors previously mentioned, isolated myofibers are examined in vitro at 15°C, which alters peak tension, V o , and power production (4,27,34). This approach provides information about the contractile mechanics intrinsic to the myofiber in a fiber type-specific manner that provides insights into the cellular factors that may influence whole muscle performance.…”

Section: Discussionmentioning

confidence: 99%

Single muscle fiber contractile properties of young competitive distance runners

Harber¹,

Trappe²

2008

Journal of Applied Physiology

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Harber M, Trappe S. Single muscle fiber contractile properties of young competitive distance runners. J Appl Physiol 105: 629 -636, 2008. First published June 5, 2008 doi:10.1152/japplphysiol.00995.2007.-The purpose of this investigation was to characterize the contractile properties of individual slow-and fast-twitch myofibers from highly trained distance runners. Muscle biopsies were obtained from the gastrocnemius of eight competitive runners (Run) and eight recreationally active individuals (Rec). Slow-twitch [myosin heavy chain (MHC) I] and fast-twitch (MHC IIa) myofibers were isolated and analyzed for diameter (m), peak force (P o; mN), unloaded contraction velocity (Vo; fiber lengths/s), and power. Maximum oxygen uptake was higher (P Ͻ 0.05) in Run (71 Ϯ 1 vs. 47 Ϯ 2 ml ⅐ kg Ϫ1 ⅐ min Ϫ1 ). Diameter of MHC I and MHC IIa fibers from Run subjects was ϳ20% greater (P Ͻ 0.05) than Rec. Peak force of the MHC IIa fibers was 31% higher (P Ͻ 0.05) in Run, whereas Po of MHC I fibers was not different between groups. No differences for specific tension (Po/cross-sectional area) were present between groups for either fiber type. Vo was higher (P Ͻ 0.05) in MHC I (ϩ70%) and MHC IIa (ϩ18%) fibers from Run subjects. In vitro peak absolute power (N ⅐ s Ϫ1 ) of both fiber types was greater (P Ͻ 0.05) in Run (131 and 85% for MHC I and MHC IIa, respectively). Additionally, normalized power (W/l) of the MHC I fibers was 64% higher in Run, whereas no differences were noted for normalized power of MHC IIa fibers. These data indicate that highly trained endurance runners have elevated contraction velocity in both slow-and fast-twitch myofibers. These characteristics of the fast-twitch muscle fibers have not been previously reported in competitive endurance athletes and may contribute to the high level of running performance in these athletes. myosin heavy chain; exercise; endurance SCIENTISTS HAVE LONG BEEN intrigued by the physiological attributes that allow elite athletes to achieve high levels of physical performance. Initial studies focused on describing the cardiovascular variables of champion athletes (1,9,23,35).

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“…These data are results of experiments conducted at relatively low temperature (15–18 °C). While this is substantially below the temperature in the intact muscle, recent data conducted at 35 °C indicate that the fiber type difference at more physiological relevant temperature is much less and in the magnitude of 1:2 between MyHC I and MyHC II fibers (Lionikas et al, 2006).…”

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confidence: 94%

Effects of strength training on muscle fiber types and size; consequences for athletes training for high‐intensity sport

Andersen

Aagaard

2010

Scandinavian Med Sci Sports

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Training toward improving performance in sports involving high intense exercise can and is done in many different ways based on a mixture of tradition in the specific sport, coaches' experience and scientific recommendations. Strength training is a form of training that now-a-days have found its way into almost all sports in which high intense work is conducted. In this review we will focus on a few selected aspects and consequences of strength training; namely what effects do strength training have of muscle fiber type composition, and how may these effects change the contractile properties of the muscle and finally how will this affect the performance of the athlete. In addition, the review will deal with muscle hypertrophy and how it develops with strength training. Overall, it is not the purpose of this review to give a comprehensive up-date of the area, but to pin-point a few issues from which functional training advises can be made. Thus, more than a review in the traditional context this review should be viewed upon as an attempt to bring sports-physiologists and coaches or others working directly with the athletes together for a mutual discussion on how recently acquired physiological knowledge are put into practise.

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Human skeletal muscle myosin function at physiological and non‐physiological temperatures

Abstract: The present results suggest a significantly reduced difference in shortening velocity between different human muscle fibre types at physiological temperature than previously reported at lower temperatures (12 or 15 degrees C) with implications for human in vivo muscle function.

Cited by 16 publications

References 41 publications

Aging, muscle fiber type, and contractile function in sprint-trained athletes

Aging, muscle fiber type, and contractile function in sprint-trained athletes

Single muscle fiber contractile properties of young competitive distance runners

Effects of strength training on muscle fiber types and size; consequences for athletes training for high‐intensity sport

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