Nuria Garatachea

Whole-body vibration training increases muscle strength and mass in older women: a randomized-controlled trial

To determine whether 10 weeks of whole‐body vibration (WBV) training has a significant effect on strength, muscle mass, muscle power, and mobility in older women, 26 subjects were randomly assigned to a WBV training group (n=13; mean age 79 years) and a control (CON) group (n=13; mean age 76 years). Maximal voluntary isometric contraction (MVIC) increased 38.8% in the WBV group, without changes in the CON group. Electromyographic activity of the vastus medialis (VM), the vastus lateralis, and the biceps femoris (BF) did not change in either group. Thigh muscle cross‐sectional area increased significantly after training in VM (8.7%) and BF (15.5%). Muscle power at 20%, 40%, and 60% MVIC decreased from pre‐test to post‐test in the CON group; however, WBV training prevented the decrease in the WBV group. Consequently, mobility, measured by the Timed Up and Go test, increased significantly after training (9.0%) only in the WBV group. Ten weeks of lower limb WBV training in older women produces a significant increase in muscle strength induced by thigh muscle hypertrophy, with no change in muscle power. The adaptations to WBV found in the present study may be of use in counteracting the loss of muscle strength and mobility associated with age‐induced sarcopenia.

Actigraph GT3X: Validation and Determination of Physical Activity Intensity Cut Points

The aims of this study were: to compare energy expenditure (EE) estimated from the existing GT3X accelerometer equations and EE measured with indirect calorimetry; to define new equations for EE estimation with the GT3X in youth, adults and older people; and to define GT3X vector magnitude (VM) cut points allowing to classify PA intensity in the aforementioned age-groups. The study comprised 31 youth, 31 adults and 35 older people. Participants wore the GT3X (setup: 1-s epoch) over their right hip during 6 conditions of 10-min duration each: resting, treadmill walking/running at 3, 5, 7, and 9 km · h⁻¹, and repeated sit-stands (30 times · min⁻¹). The GT3X proved to be a good tool to predict EE in youth and adults (able to discriminate between the aforementioned conditions), but not in the elderly. We defined the following equations: for all age-groups combined, EE (METs)=2.7406+0.00056 · VM activity counts (counts · min⁻¹)-0.008542 · age (years)-0.01380 ·  body mass (kg); for youth, METs=1.546618+0.000658 · VM activity counts (counts · min⁻¹); for adults, METs=2.8323+0.00054 · VM activity counts (counts · min⁻¹)-0.059123 · body mass (kg)+1.4410 · gender (women=1, men=2); and for the elderly, METs=2.5878+0.00047 · VM activity counts (counts · min⁻¹)-0.6453 · gender (women=1, men=2). Activity counts derived from the VM yielded a more accurate EE estimation than those derived from the Y-axis. The GT3X represents a step forward in triaxial technology estimating EE. However, age-specific equations must be used to ensure the correct use of this device.

Feelings of well being in elderly people: Relationship to physical activity and physical function

The aim of the research was to investigate in a sample of Spanish elderly whether measures of physical activity and physical function are related to feelings of well being, and whether level of dependence is a moderator in the relation of well being, physical activity and physical function. The sample was a cohort of 151 elderly people (89 women and 62 men, aged 60-98 years) from the North of Spain. Participants completed surveys including demographic characteristics, and measures of physical activity (Yale Physical Activity Survey, YPAS), instrumental activities of daily living (Barthel Index, BI) and well being (Psychological Well Being Scale, from Spanish: Escala de Bienestar Psicológico=EBP). Components of the physical function were measured by the Senior Fitness Test (SFT). Upper and lower body strength, dynamic balance, aerobic endurance, self-reported weekly energy expenditure and physical activity total time were significantly correlated with both Material and Subjective well being. All components of physical function were significantly impaired in dependent subjects when compared to independent individuals of the same sex and physical activity category. Significant differences were also observed in Subjective well being among less active dependent or independent individuals. In conclusion, physical function and physical activity are related to feelings of well being, and results emphasize the positive functional and psychological effects of physical activity in dependent subjects.

Technical variability of the GT3X accelerometer

To analyze the intra- and inter-instrument reliability of the ActiGraph GT3X accelerometer using a vibration table on each orthogonal axis and at five frequencies of motion. Ten GT3X units were subjected to a specific vibration using a motorized vibration table along the vertical, horizontal right-left and horizontal front-back axis, and at 1.1, 2.1, 3.1, 4.1 and 10.2 Hz. The 5 min data for each frequency were analyzed separately for frequency, axis effects, and inter- and intra-instrument variability. We found overall high intra-and inter-instrument reliability for the GT3X accelerometer at frequencies between 2.1 and 4.1 Hz. For frequencies ranging between 2.1 and 4.1 Hz, the intra-instrument coefficient of variation was ≤2.5%. The inter-instrument coefficient of variation ranged widely along axes and frequencies, with the lowest values (≤9%) corresponding to 2.1-4.1 Hz. The intra-class correlation coefficient for activity counts across frequencies and for all axes was 0.97. Overall, our findings support the use of the GT3X accelerometer as an accurate tool to estimate free-living physical activity, at least within those frequencies that are common to most types of human daily activities.

Sulforaphane treatment protects skeletal muscle against damage induced by exhaustive exercise in rats

Sulforaphane (SF), one of the most important isothiocyanates in the human diet, present in cruciferous vegetables, is known to have chemopreventive activities in different tissues. No data are available on its effects in the prevention of skeletal muscle damage. In this study, we investigated the potential protective effects of SF treatment on muscle damage and oxidative stress induced by an acute bout of exhaustive exercise in rats. Male Wistar rats were treated with SF (25 mg/kg body wt ip) for 3 days before undergoing an acute exhaustive exercise protocol in a treadmill (+7% slope and 24 m/min). Acute exercise resulted in a significant increase in plasma lactate dehydrogenase (LDH) and creatine phosphokinase (CPK) activities. It also resulted in a significant increase in thiobarbituric acid-reactive substances, in a significant decrease in tissue total antioxidant capacity, and in a significant decrease in NAD(P)H:quinone oxidoreductase 1 (NQO1) expression and activity in vastus lateralis muscle. SF treatment significantly increased muscle NQO1, glutathione-S-transferase, and glutathione reductase expression and activity, with no effect on glutathione peroxidase and thioredoxin reductase. The observed SF-induced upregulation of phase II enzymes was accompanied by a significant increase in nuclear erythroid 2 p45-related factor 2 expression and correlated with a significant increase in total antioxidant capacity and a decrease in plasma LDH and CPK activities. Our data demonstrate that SF acts as an indirect antioxidant in skeletal muscle and could play a critical role in the modulation of the muscle redox environment, leading to the prevention of exhaustive exercise-induced muscle damage.

Exercise attenuates the major hallmarks of aging.

Regular exercise has multi-system anti-aging effects. Here we summarize how exercise impacts the major hallmarks of aging. We propose that, besides searching for novel pharmaceutical targets of the aging process, more research efforts should be devoted to gaining insights into the molecular mediators of the benefits of exercise and to implement effective exercise interventions for elderly people.

Serum Irisin Levels, Precocious Myocardial Infarction, and Healthy Exceptional Longevity

BACKGROUND Skeletal muscles produce irisin. Growing controversy exists on the association between this myokine and chronic disease risk. On the basis of the potential protective effects that irisin could exert on both vascular function and skeletal muscle mass, we hypothesized that an elevated level of this molecule may contribute to successful aging. METHODS Serum irisin levels were measured using enzyme-linked immunosorbent assay in disease-free centenarians, young healthy controls, and patients with precocious acute myocardial infarction. RESULTS We found the highest levels of serum irisin in disease-free centenarians (35.3 ± 5.5 ng/mL) compared with young healthy controls (20.7 ± 6.3 ng/mL) and especially with young patients with acute myocardial infarction (15.1 ± 5.4 ng/mL). CONCLUSIONS Our study demonstrates that healthy centenarians are characterized by increased serum irisin levels, whereas levels of this molecule were found to be significantly lower in young patients with myocardial infarction. Our findings may prompt further research into the role played by irisin not only in vascular disorders but also in life span modulation.

Genes and the ageing muscle: a review on genetic association studies

Western populations are living longer. Ageing decline in muscle mass and strength (i.e. sarcopenia) is becoming a growing public health problem, as it contributes to the decreased capacity for independent living. It is thus important to determine those genetic factors that interact with ageing and thus modulate functional capacity and skeletal muscle phenotypes in older people. It would be also clinically relevant to identify ‘unfavourable’ genotypes associated with accelerated sarcopenia. In this review, we summarized published information on the potential associations between some genetic polymorphisms and muscle phenotypes in older people. A special emphasis was placed on those candidate polymorphisms that have been more extensively studied, i.e. angiotensin-converting enzyme (ACE) gene I/D, α-actinin-3 (ACTN3) R577X, and myostatin (MSTN) K153R, among others. Although previous heritability studies have indicated that there is an important genetic contribution to individual variability in muscle phenotypes among old people, published data on specific gene variants are controversial. The ACTN3 R577X polymorphism could influence muscle function in old women, yet there is controversy with regards to which allele (R or X) might play a ‘favourable’ role. Though more research is needed, up-to-date MSTN genotype is possibly the strongest candidate to explain variance among muscle phenotypes in the elderly. Future studies should take into account the association between muscle phenotypes in this population and complex gene–gene and gene–environment interactions.

The Effects of Movement Velocity During Squatting on Energy Expenditure and Substrate Utilization in Whole-Body Vibration

The purpose of this study was to examine whether and how cycle time duration affects energy expenditure and substrate utilization during whole-body vibration (WBV). Nine men performed 3 squatting exercises in execution frequency cycles of 6, 4, and 2 seconds to 90° knee flexion with vibration (Vb-) (frequency was set at 30 Hz and the amplitude of vibration was 4 mm) and without vibration (Vb-) during 3 minutes, each with an additional load of 30% of the subjects body weight. A 2-way analysis of variance for &OV0312;O2 revealed a significant vibration condition main effect (p < 0.001) and a cycle time duration effect (p < 0.001). When differences were analyzed by Fishers LSD test, cycle time duration of 2 seconds was significantly different from 4 and 6 seconds, both in Vb+ and Vb-. Total energy expenditure (EEtot), carbohydrate oxidation rate (EEcho), and fat oxidation rate (EEfat) demonstrated a significant vibration condition main effect (EEtot: p < 0.01; EEcho: p < 0.001; EEfat: p < 0.001) and cycle time duration main effect (EEtot and EEcho: p < 0.001; EEfat: p < 0.01). EEtot,EEcho, and EEfat post hoc comparisons indicated that values for the 2-second test significantly differed from 4 and 6 seconds when compared in the same vibration condition. &OV0312;O2 and EE values were greater in Vb+ than in Vb-conditions with the same cycle time duration. Our study confirms that squatting at a greater frequency helps to maximize energy expenditure during exercise with or without vibration. Therefore, cycle time duration must be controlled when vibration exercise is prescribed.

Eccentric exercise induces nitric oxide synthase expression through nuclear factor-κB modulation in rat skeletal muscle

This study aimed to investigate the effect of eccentric exercise on the expression of the different nitric oxide synthase (NOS) isoforms in rat deep vastus lateralis muscle. Twenty-four rats were allocated to four experimental groups: rested control group, acutely exercised group after an intermittent downhill protocol for 90 min, acutely exercised group treated with pyrrolidine dithiocarbamate (100 mg/kg ip) for 24 and 1 h before the acute exercise bout, and acutely exercised group with a previous submaximal eccentric training of 8 wk. Acutely exercised rats showed increased levels of protein tyrosine nitration, NF-kappaB binding, and phospho-I kappaB alpha content. A significant increase was observed in mRNA level and protein content of neuronal NOS, inducible NOS, and endothelial NOS. The binding of NF-kappaB to the NOS isoform promoters, measured by a chromatin immunoprecipitation assay, was undetectable in rested rats, whereas it was evident in acutely exercised animals. All of these effects were partially abolished by pyrrolidine dithiocarbamate treatment and by training. In summary, our findings provide a direct link between the NF-kappaB signaling cascade and NOS expression in skeletal muscle following eccentric exercise and suggest a modulation of the expression of the three NOS isoforms by this transcription factor.