Effect of aging on human adductor pollicis muscle function

Narici, Marco V.; Bordini, M.; Cerretelli, Paolo

doi:10.1152/jappl.1991.71.4.1277

Cited by 173 publications

(147 citation statements)

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“…Since the fusion of muscle contraction should occur more readily at low rates of excitation in type I fibers, the decrease in the motor unit firing rate in the elderly would be a neurophysiological adaptation to activate type I muscle fibers efficiently and minimize high-frequency fatigue (Moritani et al 1985). In fact, Narici et al (1991) had already showed that aged muscle was tetanized at lower fusion frequencies in the human adductor pollicis muscle by nerve stimulation (Narici et al 1991). Also, a negative relationship between the maximal motor unit firing rate and afterhyperpolarization (AHP) in the tibialis anterior muscle was demonstrated in the elderly (r = −0.37, p = 0.004) but not in the young (r = −0.05, p = 0.72) (Christie and Kamen 2010), suggesting that AHP elongation contributes to the age-related decrease in the motor unit firing rate.…”

Section: Discussionmentioning

confidence: 99%

Age-related changes in motor unit firing pattern of vastus lateralis muscle during low-moderate contraction

Watanabe

Holobar

Kouzaki

et al. 2016

AGE

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Age-related changes in motor unit activation properties remain unclear for locomotor muscles such as quadriceps muscles, although these muscles are preferentially atrophied with aging and play important roles in daily living movements. The present study investigated and compared detailed motor unit firing characteristics for the vastus lateralis muscle during isometric contraction at low to moderate force levels in the elderly and young. Fourteen healthy elderly men and 15 healthy young men performed isometric ramp-up contraction to 70 % of the maximal voluntary contractions (MVC) during knee extension. Multichannel surface electromyograms were recorded from the vastus lateralis muscle using a two-dimensional grid of 64 electrodes and decomposed with the convolution kernel compensation technique to extract individual motor units. Motor unit firing rates in the young were significantly higher (~+29.7 %) than in the elderly (p < 0.05). There were significant differences in firing rates among motor units with different recruitment thresholds at each force level in the young (p < 0.05) but not in the elderly (p > 0.05). Firing rates at 60 % of the MVC force level for the motor units recruited at <20 % of MVC were significantly correlated with MVC force in the elderly (r = 0.885, p < 0.0001) but not in the young (r = 0.127, p > 0.05). These results suggest that the motor unit firing rate in the vastus lateralis muscle is affected by aging and muscle strength in the elderly and/or age-related strength loss is related to motor unit firing/ recruitment properties.

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Section: Discussionmentioning

confidence: 99%

Age-related changes in motor unit firing pattern of vastus lateralis muscle during low-moderate contraction

Watanabe

Holobar

Kouzaki

et al. 2016

AGE

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“…Eleven adult subjects Յ50 yr old (19-50 yr) constituted the adult group (four female and seven male). This age range was selected to exclude subjects likely to have significant functional changes as found in hand muscles of subjects older than 60 yr (40). Eight elderly subjects from 67 to 85 yr old were studied (three female and five male).…”

Section: Methodsmentioning

confidence: 99%

Mild mitochondrial uncoupling impacts cellular aging in human muscles in vivo

Amara¹,

Shankland²,

Jubrias³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

200

195

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Faster aging is predicted in more active tissues and animals because of greater reactive oxygen species generation. Yet age-related cell loss is greater in less active cell types, such as type II muscle fibers. Mitochondrial uncoupling has been proposed as a mechanism that reduces reactive oxygen species production and could account for this paradox between longevity and activity. We distinguished these hypotheses by using innovative optical and magnetic resonance spectroscopic methods applied to noninvasively measured ATP synthesis and O 2 uptake in vivo in human muscle. Here we show that mitochondrial function is unchanged with age in mildly uncoupled tibialis anterior muscle (75% type I) despite a high respiratory rate in adults. In contrast, substantial uncoupling and loss of cellular [ATP] indicative of mitochondrial dysfunction with age was found in the lower respiring and well coupled first dorsal interosseus (43-50% type II) of the same subjects. These results reject respiration rate as the sole factor impacting the tempo of cellular aging. Instead, they support mild uncoupling as a mechanism protecting mitochondrial function and contributing to the paradoxical longevity of the most active muscle fibers. magnetic resonance spectroscopy ͉ optical spectroscopy ͉ oxidative phosphorylation T he rate-of-living hypothesis proposes that higher rates of oxidative metabolism cause an increased production of reactive oxygen species (ROS) (1), leading to oxidative damage and mitochondrial dysfunction with age. However, mice with the lowest resting respiration rate have been shown to have the shortest longevity (2). Similarly, isolated muscle fibers show greater generation of ROS in type II fibers (3), which have the lowest oxidative capacity and chronic activity levels. This fiber type also has the shortest longevity and is the first to be lost with age (4). Thus, the tempo of aging appears to vary among mice and muscle fiber types but in an opposite manner than predicted by the rate-of-living hypothesis, with the least active having the shortest longevity.A physiological mechanism that could account for this paradox is mild mitochondrial uncoupling, which has been proposed to ameliorate ROS production by reducing reverse electron flow and superoxide generation (5). Consistent with this prediction are findings in mice with high respiration rates that showed elevated proton leak in isolated muscle mitochondria as a result of activation of the adenine nucleotide translocator and uncoupling protein 3. Mild uncoupling resulting from activation of these mitochondrial factors in type I muscle fibers could reduce ROS production, protect mitochondria from damage, and account for the longevity of this fiber type with age. A number of studies have provided evidence of mild uncoupling in human muscles (6, 7) but have not tested whether this uncoupling protects against mitochondrial dysfunction and cellular aging.New methods permit measurement of mitochondrial coupling in vivo by using a combination of noninvasive spectroscopi...

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“…In normal weight individuals, ageing is known to be accompanied by a significant decline in maximal strength and explosive force production, 21,22 as well as power output, 23,24 which seem to be explained to a great extent by the reduction in muscle mass, 25,26 although age-related changes in hormone balance 27 and a lower capacity of elderly for neuromuscular response in controlling postural sway 28 can play an important role. In agreement with the age-related decrease in muscle performance presently observed in our obese population, the decline in maximal strength and power has been reported to take place at a rate of about 1-3% per year in lower limb extensor muscles.…”

Section: Muscular Power Output In Obesitymentioning

confidence: 99%

Influence of gender, age and BMI on lower limb muscular power output in a large population of obese men and women

et al. 2003

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OBJECTIVE:To depict the general trends of muscle anaerobic performance in obese subjects within a wide range of age and body weight. DESIGN: Cross-sectional study for the measurement of lower limb maximal anaerobic power output with a modification of the Margaria stair climbing test in a large population of obese subjects of both genders within a wide span of age (18-80 y) and body mass index (BMI, 30-68 kg m À2 ). Furthermore, body composition was also determined by bioimpedance analysis in a representative subgroup, in order to evaluate the relationships between fat-free mass (FFM) and power output. SUBJECTS: A total of 1298 obese subjects (486 males, 812 females) from an Italian population seeking medical support for body weight reduction. Within this sample, a consistent subgroup of 193 subjects (59 males, 134 females) was also selected for accessory study of body composition. RESULTS: In general, male subjects developed significantly higher lower limb power output ( . W) than female subjects (Po0.001-0.01), both in absolute terms and per unit body mass. In both genders, . W was influenced negatively by age (Po0.001) and positively by BMI (Po0.001). While the effect of age was similar in both genders, BMI had a different positive effect in male and in female subjects, being more definite in male subjects. In the subgroup, FFM was found to depend both on age and BMI, in a fashion comparable with that displayed by .W. The gender-related differences in . W disappeared when expressed per unit FFM and a significant linear correlation was found between FFM and . W, both in male and female subjects (R 2 ¼ 0.32-0.51, Po0.001). CONCLUSIONS: The lower limb maximal power output is significantly higher in obese male subjects than in female subjects, being negatively influenced by age but positively related to BMI. Female subjects appear to be at a greater disadvantage for effect of obesity, the major motor limitations being suffered by older women with higher BMI. These gender differences in ageand BMI-dependent .W changes seem to be related to changes in FFM in the subgroup in whom body composition was studied.

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Effect of aging on human adductor pollicis muscle function

Cited by 173 publications

References 0 publications

Age-related changes in motor unit firing pattern of vastus lateralis muscle during low-moderate contraction

Age-related changes in motor unit firing pattern of vastus lateralis muscle during low-moderate contraction

Mild mitochondrial uncoupling impacts cellular aging in human muscles in vivo

Influence of gender, age and BMI on lower limb muscular power output in a large population of obese men and women

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