Age-dependent effects of treadmill exercise during a period of inactivity

Arora, Pooja; Husom, Aimee D.; Ferrington, Deborah A.; Thompson, LaDora V.

doi:10.1016/j.exger.2008.03.006

Cited by 6 publications

(5 citation statements)

References 27 publications

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“…Thus, knowledge is lacking about the effect of short‐term disuse on single muscle fibre contractile function in old healthy individuals, and it also remains unknown whether the potential adaptive modulations differ from those occurring in young healthy individuals. Albeit data are lacking in humans, findings from animal studies indicate that ageing may be associated with an elevated susceptibility to the deleterious effects of short‐term disuse on the contractile function of single muscle fibres (Thompson et al 1998; Arora et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Effects of ageing on single muscle fibre contractile function following short‐term immobilisation

Hvid

Ørtenblad

Aagaard

et al. 2011

The Journal of Physiology

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Non-technical summary The contractile function of human single muscle fibres is of particular importance for whole muscle contractile function. Yet, whereas ageing and short-term disuse (immobilisation) separately have been shown to impair single fibre contractile function, very little attention has been given to their combined effects. We show that 2 weeks of lower limb immobilisation reduces force and specific force (force per cross-sectional area) of both slow and fast single muscle fibres and that this occurred to a similar extent in young and old individuals. In contrast, disuse led to reduced Ca 2+ sensitivity in fast fibres of young and in slow fibres of old, respectively. These results help us to better understand the underlying physiological mechanisms responsible for the deleterious effects of short-term disuse on whole muscle contractile function in both young and old.Abstract Very little attention has been given to the combined effects of healthy ageing and short-term disuse on the contractile function of human single muscle fibres. Therefore, the present study investigated the effects of 2 weeks of lower limb cast immobilisation (i.e. disuse) on selected contractile properties of single muscle fibres (n = 378) from vastus lateralis of nine young (24 ± 1 years) and eight old (67 ± 2 years) healthy men with comparable levels of physical activity. Prior to immobilisation, MHC IIa fibres produced higher maximum Ca 2+ -activated force (approx. 32%) and specific force (approx. 33%) and had lower Ca 2+ sensitivity than MHC I fibres (P < 0.05), with no differences between young and old. After immobilisation, the decline in single fibre force (MHC I: young 21% and old 22%; MHC IIa: young 22% and old 30%; P < 0.05) as well as specific force (MHC I: young 14% and old 13%; MHC IIa: young 18% and old 25%; P < 0.05) was more pronounced in MHC IIa fibres compared to MHC I fibres (P < 0.05), with no differences between young and old. Notably, there was a selective decrease in Ca 2+ sensitivity in MHC IIa fibres of young (P < 0.05) and in MHC I fibres of old individuals (P < 0.05), respectively. In conclusion, 2 weeks of lower limb immobilisation caused greater impairments in single muscle fibre force and specific force in MHC IIa than MHC I fibres independently of age. In contrast, immobilisation-induced changes in Ca 2+ sensitivity that were dependent on age and MHC isoform.

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Section: Introductionmentioning

confidence: 99%

Effects of ageing on single muscle fibre contractile function following short‐term immobilisation

Hvid

Ørtenblad

Aagaard

et al. 2011

The Journal of Physiology

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“…Physiologically, this protocol proved to be beneficial in attenuating inactivity-induced decline in fiber size and force generation for MHC type II fibers in the gastrocnemius muscle from elderly rats (2). However, with inactivity, the soleus muscle is very susceptible to inactivity-induced contractile dysfunction.…”

Section: Absolute Peak Powermentioning

confidence: 99%

“…A total of 363 single fibers were analyzed, corresponding to approximately 7 fibers per animal. The fiber diameter was determined as the average size of three places along the length of the fiber and the fiber cross-sectional area (CSA) was calculated by assuming a circular cross section (2).…”

Section: Isolation Of Single-muscle Fibers and Determination Of Fibermentioning

confidence: 99%

“…Likewise, endurance exercise training does not attenuate the decrease in contractile function in the aged (34). In a recent study that focused on old rats, a mild intermittent treadmill exercise (isotonic exercise with weight bearing; walking) during a period of inactivity was used (2). This exercise protocol stimulated or recruited the type II fibers and improved type II fiber function of the gastrocnemius muscle in the old animals (2).…”

mentioning

confidence: 99%

“…These exercise protocols include a daily, short-duration, high-load exercise (16), intermittent weight-bearing exercise (1,2,26), resistance exercise (33), and isometric exercise program (17). The degree of effectiveness of exercise during a period of inactivity on muscle functions, including power generation, varies depending on frequency, intensity, time, and type of exercise (exercise prescription).…”

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confidence: 99%

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Differential effects of mild therapeutic exercise during a period of inactivity on power generation in soleus type I single fibers with age

Kim

Thompson

2012

Journal of Applied Physiology

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Kim JH, Thompson LV. Differential effects of mild therapeutic exercise during a period of inactivity on power generation in soleus type I single fibers with age. J Appl Physiol 112: 1752-1761, 2012. First published March 15, 2012 doi:10.1152/japplphysiol.01077.2011.-The purpose of this study was to investigate the effects of mild therapeutic exercise (treadmill) in preventing the inactivity-induced alterations in contractile properties (e.g., power, force, and velocity) of type I soleus single fibers in three different age groups. Young adult (5-to 12-mo-old), middle-aged (24-to 31-mo-old), and old (32-to 40-mo-old) F344BNF1 rats were randomly assigned to three experimental groups: weightbearing control (CON), non-weight bearing (NWB), and NWB with exercise (NWBX). NWB rats were hindlimb suspended for 2 wk, representing inactivity. The NWBX rats were hindlimb suspended for 2 wk and received therapeutic exercise on a treadmill four times a day for 15 min each. Peak power and isometric maximal force were reduced following hindlimb suspension (HS) in all three age groups. HS decreased fiber diameter in young adult and old rats (Ϫ21 and Ϫ12%, respectively). Specific tension (isometric maximal force/cross-sectional area) was significantly reduced in both the middle-aged (Ϫ36%) and old (Ϫ23%) rats. The effects of the mild therapeutic exercise program on fiber diameter and contractile properties were age specific. Mild treadmill therapeutic exercise attenuated the HS-induced reduction in fiber diameter (ϩ17%, 93% level of CON group) and peak power (N·fiber length·s Ϫ1 ) (ϩ46%, 63% level of CON group) in young adult rats. In the middle-aged animals, this exercise protocol improved peak power (ϩ60%, 100% level of CON group) and normalized power (kN·m Ϫ2 ·fiber length·s Ϫ1 ) (ϩ45%, 108% level of CON group). Interestingly, treadmill exercise resulted in a further reduction in shortening velocity (Ϫ42%, 67% level of CON group) and specific tension (Ϫ29%, 55% level of CON group) in the old animals. These results suggest that mild treadmill exercise is beneficial in attenuating and preventing inactivity-induced decline in peak power of type I soleus single fibers in young adult and middle-aged animals, respectively. However, this exercise program does not prevent the HS-induced decline in muscle function in the old animals.

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Initiating exercise training in late middle age minimally protects muscle contractile function and increases myocyte oxidative damage in senescent rats

Thomas

Khan

Betik

et al. 2010

Experimental Gerontology

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Age-dependent effects of treadmill exercise during a period of inactivity

Cited by 6 publications

References 27 publications

Effects of ageing on single muscle fibre contractile function following short‐term immobilisation

Effects of ageing on single muscle fibre contractile function following short‐term immobilisation

Differential effects of mild therapeutic exercise during a period of inactivity on power generation in soleus type I single fibers with age

Initiating exercise training in late middle age minimally protects muscle contractile function and increases myocyte oxidative damage in senescent rats

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