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To determine the influence of androgen receptor CAG and GGN repeat polymorphisms on fat mass and maximal fat oxidation ( MFO), CAG and GGN repeat lengths were measured in 128 young boys, from which longitudinal data were obtained in 45 of them [mean ± SD: 12.8 ± 3.6 years old at recruitment, and 27.0 ± 4.8 years old at adult age]. Subjects were grouped as CAG short ( CAGS) if harboring repeat lengths ≤ 21, the rest as CAG long ( CAGL); and GGN short ( GGNS) if GGN repeat lengths ≤ 23, or long if > 23 ( GGNL). CAGS and GGNS were associated with lower adiposity than CAGL or GGNL ( P < 0.05). There was an association between the logarithm of CAG repeats polymorphism and the changes of body mass ( r = 0.34, P = 0.03). At adult age, CAGS men showed lower accumulation of total body and trunk fat mass, and lower resting metabolic rate ( RMR) and MFO per kg of total lean mass compared with CAGL ( P < 0.05). GGNS men also showed lower percentage of body fat ( P < 0.05). In summary, androgen receptor CAG and GGN repeat polymorphisms are associated with RMR, MFO, fat mass, and its regional distribution in healthy male adolescents, influencing fat accumulation from adolescence to adult age. [ABSTRACT FROM AUTHOR]

End-tidal PCO2 ( PETCO2) has been used to estimate arterial pressure CO2 ( PaCO2). However, the influence of blood temperature on the PaCO2 has not been taken into account. Moreover, there is no equation validated to predict PaCO2 during exercise in severe acute hypoxia. To develop a new equation to predict temperature-corrected PaCO2 values during exercise in normoxia and severe acute hypoxia, 11 volunteers (21.2 ± 2.1 years) performed incremental exercise to exhaustion in normoxia ( Nox, PIO2: 143 mmHg) and hypoxia ( Hyp, PIO2: 73 mmHg), while arterial blood gases and temperature ( ABT) were simultaneously measured together with end-tidal PCO2 ( PETCO2). The Jones et al. equation tended to underestimate the temperature corrected (tc) PaCO2 during exercise in hypoxia, with greater deviation the lower the PaCO2tc ( r = 0.39, P < 0.05). The new equation has been developed using a random-effects regression analysis model, which allows predicting PaCO2tc both in normoxia and hypoxia: PaCO2tc = 8.607 + 0.716 × PETCO2 [ R2 = 0.91; intercept SE = 1.022 ( P < 0.001) and slope SE = 0.027 ( P < 0.001)]. This equation may prove useful in noninvasive studies of brain hemodynamics, where an accurate estimation of PaCO2 is needed to calculate the end-tidal-to-arterial PCO2 difference, which can be used as an index of pulmonary gas exchange efficiency. [ABSTRACT FROM AUTHOR]

Life expectancy has increased worldwide alongside a rise in disability prevalence during old age. The impact and interrelationship among the precursors of disability in midlife remain to be better understood. Furthermore, investigating whether lifestyle factors may potentially influence health outcomes and the prognosis of vascular disease could be especially relevant among the middle-aged population, which is a priority subpopulation when prevention is the goal. This is an observational, cross-sectional and population-based study. Participants, between 50 and 55 years old, are randomly selected from the municipality of Toledo (Spain). There are six non-consecutive days for the assessments, providing enough rest between evaluations. Participants perform the interview of the Toledo Study for Healthy Aging. Blood pressure monitoring and a resting electrocardiogram are also recorded. Then, resting peripheral and cerebral vascular measurements along with muscle size and architecture are assessed. Blood and urine samples, and body composition data are collected after an overnight fasting. On a different visit, physical performance and muscle function tests are performed. Additionally, brain magnetic resonance imaging is conducted. And finally, an accelerometer is given to the participants for a week. Frailty is evaluated by Frailty Trait Scale and Fried Frailty Phenotype. This project will shed light on the associations between frailty, early cognitive impairment, and vascular aging during midlife, and on the role that lifestyles play in their development. Lastly, this project will provide meaningful implications for public health strategies aimed at promoting healthy aging in later life., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Objectives: To analyse the force-velocity relationship changes in response to two different training programmes differing in the set configuration (cluster vs. traditional), and their impact on physical function and frailty in pre-frail and frail older adults., Methods: 43 pre-frail and frail (Frailty Phenotype ≥ 1 criteria) older adults (81.4 ± 5.1 years) participated in this study. Participants were assigned to cluster (CT; n = 10; 10-s intra-set rest), traditional (TT; n = 13; no intra-set rest) or control (CON; n = 20) groups. Force-velocity relationship (F 0 , V 0 and P max ), physical function (Short Physical Performance Battery, SPPB) and frailty (Frailty Phenotype, FP) were assessed at baseline and after the training programme., Results: Both CT and TT groups showed similar improvements in P max after training (CT =  + 36.7 ± 34.2 W; TT =  + 33.8 ± 44.6 W; both p < 0.01). V 0 was improved by both CT (+ 0.08 ± 0.06 m s -1 ; p < 0.01), and TT (+ 0.07 ± 0.15 m s -1 , p > 0.05). F 0 remained unchanged in CT (+ 68.6 ± 224.2 N, p > 0.05) but increased in TT (+ 125.4 ± 226.8 N, p < 0.05). Finally, SPPB improved in both training conditions (CT =  + 2.3 ± 1.3 points; TT =  + 3.0 ± 1.2 points; both p < 0.05) and in the CON group (+ 0.9 ± 1.4 points, p < 0.05). CT and TT reduced their FP (CT = - 1.1 criteria; TT = - 1.6 criteria; both p < 0.01), while no changes were observed in the CON group (- 0.2 criteria, p = 0.38)., Conclusions: Both training methods were equally effective for improving P max , physical function and reducing frailty in pre-frail and frail older people. TT may be effective for improving both force and velocity parameters, while CT may be effective for improving velocity parameters alone, although further research is required to confirm these findings., (© 2023. The Author(s).)

Introduction: Concurrent training has been shown to be a beneficial approach to improve overall health status in older adults. However, little is known about the adaptations of this type of training in the long term (i.e., after cessation of exercise), even less in older people affected by frailty syndrome. Therefore, this study aimed (i) to assess the effects of a 6-week concurrent training program composed of power-oriented resistance training and fast walking interval training on physical function, muscle power, disability in activities of daily living and frailty in pre-frail and frail older people, and (ii) to assess the effects of a 6-month detraining period on these outcomes., Methods: A total of 59 pre-frail and frail older adults (&gt;75 years old; Frailty Phenotype &gt;1) were allocated into intervention (INT; n = 32; 81.8 years; 21 women) or control (CON; n = 27; 82.5 years; 19 women) groups. Primary outcomes of this study were Short Physical Performance Battery (SPPB), relative sit-to-stand (STS) power, Barthel index, Lawton scale and Frailty Phenotype. Assessments were performed at baseline (PRE), after the concurrent training programme (POST) and after 6 months of follow-up (DET) in both groups. Mixed model repeated measures ANOVA with Bonferroni's post hoc tests was used., Results: Immediately after the intervention (∆ = POST-PRE), INT improved SPPB (∆ = 3.0 points; p &lt; 0.001), relative STS power (∆ = 0.87 W·kg-1; p &lt; 0.001) and reduced their frailty levels (∆ = -1.42 criteria; p &lt; 0.001), while no changes were observed in CON. After 6 months of detraining (∆ = DET-PRE), INT showed higher SPPB (∆ = 2.2 points; p &lt; 0.001), higher relative STS power (∆ = 0.73 W·kg-1; p &lt; 0.001) and lower frailty (∆ = -1.24 criteria; p &lt; 0.001) values than those reported at baseline, which were significantly different than those reported by CON. Both, Barthel index and Lawton scale values were not modified during the study in either group., Conclusions: The 6-week concurrent training program improved physical function, muscle power and reduced frailty in pre-frail and frail older people and these improvements were maintained above baseline levels after 6 months of detraining. However, due to the individual variability found, future studies of long-term responders versus non-responders in frail populations are required., (© 2024 S. Karger AG, Basel.)

Ageing, a sedentary lifestyle, and obesity are associated with increased oxidative stress, while regular exercise is associated with an increased antioxidant capacity in trained skeletal muscles. Whether a higher aerobic fitness is associated with increased expression of antioxidant enzymes and their regulatory factors in skeletal muscle remains unknown. Although oestrogens could promote a higher antioxidant capacity in females, it remains unknown whether a sex dimorphism exists in humans regarding the antioxidant capacity of skeletal muscle. Thus, the aim was to determine the protein expression levels of the antioxidant enzymes SOD1, SOD2, catalase and glutathione reductase (GR) and their regulatory factors Nrf2 and Keap1 in 189 volunteers (120 males and 69 females) to establish whether sex differences exist and how age, VO 2 max and adiposity influence these. For this purpose, vastus lateralis muscle biopsies were obtained in all participants under resting and unstressed conditions. No significant sex differences in Nrf2, Keap1, SOD1, SOD2, catalase and GR protein expression levels were observed after accounting for VO 2 max, age and adiposity differences. Multiple regression analysis indicates that the VO 2 max in mL.kg LLM -1 .min -1 can be predicted from the levels of SOD2, Total Nrf2 and Keap1 (R = 0.58, P < 0.001), with SOD2 being the main predictor explaining 28 % of variance in VO 2 max, while Nrf2 and Keap1 explained each around 3 % of the variance. SOD1 protein expression increased with ageing in the whole group after accounting for differences in VO 2 max and body fat percentage. Overweight and obesity were associated with increased pSer 40 -Nrf2, pSer 40 -Nrf2/Total Nrf2 ratio and SOD1 protein expression levels after accounting for differences in age and VO 2 max. Overall, at the population level, higher aerobic fitness is associated with increased basal expression of muscle antioxidant enzymes, which may explain some of the benefits of regular exercise., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: This study aimed to assess the residual effects of a 12-week concurrent training program (power training + high-intensity interval training) in older adults with chronic obstructive pulmonary disease (COPD)., Methods: A total of 21 older adults with COPD [intervention (INT), n = 8; control (CON), n = 13; 76.9 ± 6.8 years] were assessed at baseline and 10 months after the completion of the intervention by the short physical performance battery (SPPB), health-related quality of life (EQ-5D-5L), vastus lateralis muscle thickness (MT), peak pulmonary oxygen uptake (peak VO 2 ) and peak work rate (W peak ), early and late isometric rate of force development (RFD), leg and chest press maximum muscle power (LP max and CP max ), and systemic oxidative damage and antioxidant capacity., Results: Compared to baseline, after 10 months of detraining, the INT group presented increased SPPB (∆ = 1.0 point), health-related quality of life (∆ = 0.07 points), early RFD (∆ = 834 N∙s -1 ), LP max (∆ = 62.2 W), and CP max (∆ = 16.0 W) (all p < 0.05). In addition, a positive effect was noted in INT compared to CON regarding MT and W peak (both p < 0.05). No between-group differences were reported in peak VO 2 , late RFD, systemic oxidative damage, and antioxidant capacity from baseline to 10 months after the completion of the intervention (all p > 0.05)., Conclusions: Twelve weeks of concurrent training were enough to ensure improved physical function, health-related quality of life, early RFD and maximum muscle power and to preserve MT and W peak but not peak VO 2 , late RFD, systemic oxidative damage and antioxidant capacity in the subsequent 10 months of detraining in older adults with COPD., (© 2023 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

Purpose: This study aimed to examine the associations of accelerometer-derived steps volume and intensity with hospitalizations and all-cause mortality in older adults., Methods: This prospective cohort study involved 768 community-dwelling Spanish older adults (78.8 ± 4.9 years, mean ± SD; 53.9% females) from the Toledo Study for Healthy Aging (2012-2017). The number of steps per day and step cadence (steps/min) were derived from a hip-mounted accelerometer worn for at least 4 days at baseline. Participants were followed-up over a mean period of 3.1 years for hospitalization and 5.7 years for all-cause mortality. Cox proportional hazards regression models were used to estimate the individual and joint associations between daily steps and stepping intensity with hospitalizations and all-cause mortality., Results: Included participants walked 5835 ± 3445 steps/day with an intensity of 7.3 ± 4.1 steps/min. After adjusting for age, sex, body mass index (BMI), education, income, marital status and comorbidities, higher step count (hazard ratio (HR) = 0.95, 95% confidence interval (95%CI: 0.90-1.00, and HR = 0.87, 95%CI: 0.81-0.95 per additional 1000 steps) and higher step intensity (HR = 0.95, 95%CI: 0.91-0.99, and HR = 0.89, 95%CI: 0.84-0.95 per each additional step/min) were associated with fewer hospitalizations and all-cause mortality risk, respectively. Compared to the group having low step volume and intensity, individuals in the group having high step volume and intensity had a lower risk of hospitalization (HR = 0.72, 95%CI: 0.52-0.98) and all-cause mortality (HR = 0.60, 95%CI: 0.37-0.98)., Conclusion: Among older adults, both high step volume and step intensity were significantly associated with lower hospitalization and all-cause mortality risk. Increasing step volume and intensity may benefit older people., (Copyright © 2021. Production and hosting by Elsevier B.V.)

Background: The purpose of this study was to evaluate the relationship of lower-limb muscle power with mortality and hospitalization., Methods: A total of 1 928 participants from the Toledo Study for Healthy Aging were included. Muscle power was assessed with the 5-repetition sit-to-stand test and participants were classified into different groups of relative power (ie, normalized to body mass) according to sex-specific tertiles and their inability to perform the test. Mean follow-up periods for hospitalization and all-cause mortality were 3.3 and 6.3 years, respectively., Results: Compared to the high relative muscle power group, men with low (HR [95% CI] = 2.1 [1.2-3.6]) and women with very low and low (HR [95% CI] = 4.7 [3.0-7.4] and 1.8 [1.2-2.7]) relative power had an increased age-adjusted risk of hospitalization. After adjusting for several covariates (age, physical activity, body mass index education, depression, comorbidities, disability, and handgrip strength), these effects were attenuated (men and women with very low relative power: HR [95% CI] = 1.6 [0.9-2.9] and 2.8 [1.6-4.9]). The very low relative muscle power group had also an increased all-cause mortality risk (age-adjusted) in both men and women (HR [95% CI] = 2.3 [1.4-3.9] and 2.9 [1.6-5.3]). After adjusting for all the covariates, a significantly increased mortality risk was observed only in men (HR [95% CI] = 2.1 [1.1-3.8]; women HR [95% CI] = 1.6 [0.8-3.2]), with very low levels of relative power., Conclusions: Relative muscle power was independently and negatively associated with mortality and hospitalization in older adults. An augmented all-cause mortality risk was noted in the lowest group of relative muscle power., (© The Author(s) 2021. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objectives: This study aimed i) to compare relative sit-to-stand power (STS rel ) values yielded by the different equations reported in the literature; ii) to examine the associations between STS rel , derived from the equations, and age, sex, frailty and habitual gait speed (HGS); and iii) to compare the ability of the different STS rel equations to detect frailty and low HGS in older adults., Methods: 1568 participants (>65 years) were included. STS rel was calculated according to four validated equations. Frailty was assessed using the Frailty Trait Scale and HGS as the time to complete 3 m. ANOVA tests, regression analyses and receiver operator characteristic curves were used., Results: There were significant differences among the STS rel values yielded by all the equations, which were higher in men compared to women and negatively associated with age (r = -0.21 to -0.37). STS rel was positively and negative associated to HGS and frailty, respectively, in both men (r = 0.29 to 0.36 and r = -0.18 to -0.45) and women (r = 0.23 to 0.45 and r = -0.09 to -0.57) regardless of the equation used. Area under the curve values varied between 0.68 and 0.80 for Alcazar's, 0.67-0.80 for Ruiz-Cárdenas's, 0.51-0.65 for Smith's, and 0.68-0.80 for Takai's equations. Low STS rel indicated an increased probability of having both low HGS and frailty (OR [95%CI] = 1.6 to 4.5 [1.21 to 5.79]) for all equations with the exception of Smith's equations for frailty in women., Conclusions: All the equations presented adequate criterion validity, however, the Alcazar's equation showed the highest level of clinical relevance according to its ability to identify older people with frailty and low HGS., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

This study investigated the acute responses to volume-load-matched heavy-load (80% 1RM) versus light-load (40% 1RM) power-oriented resistance training sessions in well-functioning older adults. Using a randomized cross-over design, 15 volunteers completed each condition on a leg press. Neuromuscular (maximal isometric force and rate of force development) and functional performance (power during sit-to-stand test), lactate, and muscle damage biochemistry (creatine kinase, lactate dehydrogenase and C-reactive protein serum concentration) were assessed pre- and post-exercise. Performance declines were found after heavy-load (Cohen's d effect size (d); maximal isometric force=0.95 d; rate of force development=1.17 d; sit-to-stand power =0.38 d, all p<0.05) and light-load (maximal isometric force=0.45 d; rate of force development=0.9 d; sit-to-stand power=1.17 d, all p<0.05), while lactate concentration increased only after light-load (1.7 d, p=0.001). However, no differences were found between conditions (all p>0.05). Both conditions increased creatine kinase the day after exercise (marginal effect=0.75 d, p<0.001), but no other blood markers increased (all, p>0.05). Irrespective of the load used, power training induced non-clinically significant decreases in sit-to-stand performance, moderate declines in maximal isometric force, but pronounced decreases in the rate of force development. Furthermore, the metabolic stress and muscle damage were minor; both sessions were generally well tolerated by well-functioning older adults without previous experience in resistance training., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

The study aimed to determine the levels of skeletal muscle angiotensin-converting enzyme 2 (ACE2, the SARS-CoV-2 receptor) protein expression in men and women and assess whether ACE2 expression in skeletal muscle is associated with cardiorespiratory fitness and adiposity. The level of ACE2 in vastus lateralis muscle biopsies collected in previous studies from 170 men (age: 19-65 years, weight: 56-137 kg, BMI: 23-44) and 69 women (age: 18-55 years, weight: 41-126 kg, BMI: 22-39) was analyzed in duplicate by western blot. VO 2 max was determined by ergospirometry and body composition by DXA. ACE2 protein expression was 1.8-fold higher in women than men (p = 0.001, n = 239). This sex difference disappeared after accounting for the percentage of body fat (fat %), VO 2 max per kg of legs lean mass (VO 2 max-LLM) and age (p = 0.47). Multiple regression analysis showed that the fat % (β = 0.47) is the main predictor of the variability in ACE2 protein expression in skeletal muscle, explaining 5.2% of the variance. VO 2 max-LLM had also predictive value (β = 0.09). There was a significant fat % by VO 2 max-LLM interaction, such that for subjects with low fat %, VO 2 max-LLM was positively associated with ACE2 expression while as fat % increased the slope of the positive association between VO 2 max-LLM and ACE2 was reduced. In conclusion, women express higher amounts of ACE2 in their skeletal muscles than men. This sexual dimorphism is mainly explained by sex differences in fat % and cardiorespiratory fitness. The percentage of body fat is the main predictor of the variability in ACE2 protein expression in human skeletal muscle., (© 2021 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

The purposes of this study were: (i) to evaluate the association of sit-to-stand (STS) power and body composition parameters [body mass index (BMI) and legs skeletal muscle index (SMI)] with age; (ii) to provide cut-off points for low relative STS power (STS rel ), (iii) to provide normative data for well-functioning older adults and (iv) to assess the association of low STS rel with negative outcomes. Cross-sectional design (1369 older adults). STS power parameters assessed by validated equations, BMI and Legs SMI assessed by dual-energy X-ray absorptiometry were recorded. Sex- and age-adjusted segmented and logistic regression analyses and receiver operator characteristic curves were used. Among men, STS rel showed a negative association with age up to the age of 85 years (- 1.2 to - 1.4% year-1 ; p < 0.05). In women, a negative association with age was observed throughout the old adult life (- 1.2 to - 2.0% year-1 ; p < 0.001). Cut-off values for low STS rel were 2.5 W kg -1 in men and 1.9 W kg -1 in women. Low STS rel was associated with frailty (OR [95% CI] = 5.6 [3.1, 10.1]) and low habitual gait speed (HGS) (OR [95% CI] = 2.7 [1.8, 3.9]) in men while low STS rel was associated with frailty (OR [95% CI] = 6.9 [4.5, 10.5]) low HGS (OR [95% CI] = 2.9 [2.0, 4.1]), disability in activities of daily living (OR [95% CI] = 2.1 [1.4, 3.2]), and low quality of life (OR [95%CI] = 1.7 [1.2, 2.4]) in women. STS rel declined with increasing age in both men and women. Due to the adverse outcomes related to STS rel , the reported cut-off points can be used as a clinical tool to identify low STS rel among older adults., (© 2021. The Author(s).)

Background: Cross-sectional evidence exists on the beneficial effects of breaks in sedentary time (BST) on frailty in older adults. Nonetheless, the longitudinal nature of these associations is unknown. This study aimed to investigate the direction and temporal order of the association between accelerometer-derived BST and frailty over time in older adults., Methods: This longitudinal study analyzed a total of 186 older adults aged 67-90 (76.7 ± 3.9 years; 52.7% females) from the Toledo Study for Healthy Aging over a 4-year period. Number of daily BST was measured by accelerometry. Frailty was assessed with the Frailty Trait Scale. Multiple cross-lagged panel models were used to test the temporal and reciprocal relationship between BST and frailty., Results: For those physically inactive (n = 126), our analyses revealed a reciprocal inverse relationship between BST and frailty, such as higher initial BST predicted lower levels of later frailty (standardized regression coefficient [β] = -0.150, 95% confidence interval [CI] = -0.281, -0.018; p < .05); as well as initial lower frailty levels predicted higher future BST (β = -0.161, 95% CI = -0.310, -0.011; p < .05). Conversely, no significant pathway was found in the active participants (n = 60)., Conclusions: In physically inactive older adults, the relationship between BST and frailty is bidirectional, while in active individuals no associations were found. This investigation provides preliminary longitudinal evidence that breaking-up sedentary time more often reduces frailty in those older adults who do not meet physical activity recommendations. Targeting frequent BST may bring a feasible approach to decrease the burden of frailty among more at-risk inactive older adults., (© The Author(s) 2020. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objectives: This study aimed i) to assess the assumptions made in the sit-to-stand (STS) muscle power test [body mass accelerated during the ascending phase (90% of total body mass), leg length (50% of total body height) and concentric phase (50% of total STS time)], ii) to compare force plate-derived (FPD) STS power values with those derived from the STS muscle power test; and iii) to analyze the relationships of both measurements with physical function., Material and Methods: Fifty community-dwelling older adults (71.3 ± 4.4 years) participated in the present investigation. FPD STS power was calculated as the product of measured force (force platform) and velocity [difference between leg length (DXA scan) and chair height, divided by time (obtained from FPD data and video analysis)], and compared to estimated STS power using the STS muscle power test. Physical function was assessed by the timed-up-and-go (TUG) velocity, habitual gait speed (HGS) and maximal gait speed (MGS). Paired t-tests, Bland-Altman plots and regressions analyses were conducted., Results: Body mass accelerated during the STS phase was 85.1 ± 3.8% (p < 0.05; compared to assumed 90%), leg length was 50.7 ± 1.3% of body height (p < 0.05; compared to 50%), and measured concentric time was 50.3 ± 4.6% of one STS repetition (p > 0.05; compared to assumed 50%). There were no significant differences between FPD and estimated STS power values (mean difference [95% CI] = 6.4 W [-68.5 to 81.6 W]; p = 0.251). Both FPD and estimated relative (i.e. normalized to body mass) STS power were significantly related to each other (r = 0.95 and ICC = 0.95; p < 0.05) and to MGS and TUG velocity after adjusting for age and sex (p < 0.05)., Conclusions: Estimated STS power was not different from FPD STS power and both measures were strongly related to each other and to maximal physical performance., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Power-oriented resistance training (PRT) is one of the most effective exercise programs to counteract neuromuscular and physical function age-related declines. However, the optimal load that maximizes these outcomes or the load-specific adaptations induced on muscle power determinants remain to be better understood. Furthermore, to investigate whether these adaptations are potentially transferred to an untrained limb (i.e., cross-education phenomenon) could be especially relevant during limb-immobilization frequently observed in older people (e.g., after hip fracture)., Methods: At least 30 well-functioning older participants (>65 years) will participate in a within-person randomized controlled trial. After an 8-week control period, the effects of two 12-week PRT programs using light vs. heavy loads will be compared using an unilateral exercise model through three study arms (light-load PRT vs. non-exercise; heavy-load PRT vs. non-exercise; and light- vs. heavy- load PRT). Muscle-tendon function, muscle excitation and morphology and physical function will be evaluated to analyze the load-specific effects of PRT in older people. Additionally, the effects of PRT will be examined on a non-exercised contralateral limb., Discussion: Tailored exercise programs are largely demanded given their potentially greater efficiency preventing age-related negative consequences, especially during limb-immobilization. This trial will provide evidence supporting the use of light- or heavy-load PRT on older adults depending on individual needs, improving decision making and exercise program efficacy., Clinical Trial Registration: NCT03724461 registration data: October 30, 2018., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Rodriguez-Lopez, Alcazar, Losa-Reyna, Martin-Espinosa, Baltasar-Fernandez, Ara, Csapo and Alegre.)

The objectives were to clarify whether the relationship between physical performance and frailty was independently and jointly mediated by movement behaviors and body composition. We analyzed 871 older adults (476 women) from The Toledo Study for Healthy Aging. Skeletal muscle index (SMI) and fat index (FI) were determined using bone densitometry. Sedentary time (ST) and moderate-to-vigorous physical activity (MVPA) were assessed using accelerometry. The Frailty Trait Scale and The Short Physical Performance Battery (SPPB) were used to evaluate frailty and physical performance, respectively. Simple and multiple mediation analyses were carried out to determine the role of movement behaviors and body composition, adjusted for potential confounders. ST and MVPA acted independently as mediators in the relationship between SPPB and frailty (0.06% for ST and 16.89% for MVPA). FI also acted as an independent mediator in the same relationship (36.47%), while the mediation role of SMI was not significant. MVPA and FI both acted jointly as mediators in this previous relationship explaining 58.15% of the model. Our data support the fact that interventions should simultaneously encourage the promotion of MVPA and strategies to decrease the FI in order to prevent or treat frailty through physical performance improvement.

Introduction: The assessment and treatment of low relative muscle power in older people has received little attention in the clinical setting when compared to sarcopenia. Our main goal was to assess the associations of low relative power and sarcopenia with other negative outcomes in older people., Methods: The participants were 1189 subjects (54% women; 65-101 years old) from the Toledo Study for Healthy Aging. Probable sarcopenia was defined as having low handgrip strength, while confirmed sarcopenia also included low appendicular skeletal muscle index (assessed by dual energy X-ray absorptiometry) (EWGSOP2's definition). Low relative (i.e. normalized to body mass) muscle power was assessed with the 5-repetition sit-to-stand power test (which uses an equation that converts sit-to-stand performance into mechanical power) and diagnosed in those subjects in the lowest sex-specific tertile. Low usual gait speed (UGS), frailty (according to Fried's criteria and the Frailty Trait Scale), limitations in basic (BADL) and instrumental activities of daily living (IADL) and poor quality of life were also recorded., Results: Age-adjusted logistic regression analyses demonstrated that low relative muscle power was associated with low UGS (odds ratio (OR) = 1.9 and 2.5), frailty (OR = 3.9 and 4.7) and poor quality of life (OR = 1.8 and 1.9) in older men and women, respectively, and with limitations in BADL (OR = 1.6) and IADL (OR = 3.8) in older women (all p < 0.05). Confirmed sarcopenia was only associated with low UGS (OR = 2.5) and frailty (OR = 5.0) in older men, and with limitations in IADL in older women (OR = 4.3) (all p < 0.05)., Conclusions: Low relative muscle power had a greater clinical relevance than low handgrip strength and confirmed sarcopenia among older people. An operational definition and algorithm for low relative muscle power case finding in daily clinical practice was presented., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: To develop short versions of the Frailty Trait Scale (FTS) for use in clinical settings., Design: Prospective population-based cohort study., Setting and Participants: Data from 1634 participants from the Toledo Study for Healthy Aging., Methods: The 12-item Frailty Trait Scale (FTS) reduction was performed based on an area under the curve (AUC) analysis adjusted by age, sex, and comorbidity. Items that maximized prognostic information for adverse events were selected. Each item score was done at the same time as the reduction, identifying the score that maximized the predictive ability for adverse events. For each short version of the FTS, cutoffs that optimized the prognostic information (sensitivity and specificity) were chosen, and their predictive value was later compared with a surrogate gold standard for frailty (the Fried Phenotype)., Results: Two short forms, the 5-item (FTS 5 ) (range 0-50) and 3-item (FTS 3 ) (range 0-30), were identified, both with AUCs for health adverse events similar to the 12-item FTS. The identified cutoffs were >25 for the FTS 5 scale and >15 for the FTS 3 . The frailty prevalence with these cutoffs was 24% and 20% for the FTS 5 and FTS 3 , respectively, whereas frailty according to Fried Phenotype (FP) reached 8% and prefrailty reached 41%. In general, the FTS 5 showed better prognostic performance than the FP, especially with prefrail individuals, in whom the FTS 5 form identified 65% of participants with an almost basal risk and 35% with a very high risk for mortality (OR: 4) and frailty (OR: 6.6-8.7), a high risk for hospitalization (OR: 1.9-2.1), and a moderate risk for disability (OR: 1.7) who could be considered frail. The FTS 3 form had worse performance than the FTS 5 , showing 31% of false negatives between frail participants identified by FP with a high risk of adverse events., Conclusions and Implications: The FTS 5 is a short scale that is easy to administer and has a similar performance to the FTS, and it can be used in clinical settings for frailty diagnosis and evolution., (Copyright © 2019 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.)

Frailty is associated with poor bone health and osteoporosis, and physical activity (PA) is one of the best treatments for both pathologies in older adults. Nonetheless, because daily time is limited, how the time is distributed during the waking hours is critical. The waking hours are spent according to different movement behaviors: sedentary behaviors (SB), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA). The aim of this study was to use compositional data analyses to examine the effects of the change in movement behaviors on bone health during aging in older people, related to the changes in their frailty levels. We analyzed 227 older people aged 65 to 94 (125 women and 102 men) over a 4-year period. Movement behaviors were assessed using accelerometry. Both bone mineral density (BMD) and bone mineral content (BMC) were determined using bone densitometry. The Frailty Trait Scale was used to divide the sample by frailty level evolution during aging. The R statistical system was used for the compositional data analysis and, in addition, all models were adjusted for several covariates. The changes in the distribution of all movement behaviors within a waking hour period were significantly associated with spine and femoral neck BMD changes in the subgroup with a positive change in frailty level and spine BMC in the subgroup with no change in frailty level (p ≤ .05). Likewise, MVPA relative to the change in other movement behaviors was also associated in both subgroups with higher BMD and BMC, respectively, in the same body areas (p ≤ .05). No significant associations were found in the negative change in frailty level subgroup. Older people who achieved a positive change in frailty level during a 4-year period showed higher BMD changes compared to those with no changes or increases in their frailty level. Therefore, increasing MVPA relative to the change in the other movement behaviors during a 4-year period could perhaps produce bone health improvements in the elderly that do not worsen their frailty level. © 2020 American Society for Bone and Mineral Research., (© 2020 American Society for Bone and Mineral Research.)

Background: There has been limited longitudinal assessment of the relationship between moderate-to-vigorous physical activity (MVPA) and sedentary behaviour (SB) with frailty, and no studies have explored the possibility of reverse causality. This study aimed to determine the potential bidirectionality of the relationship between accelerometer-assessed MVPA, SB, and frailty over time in older adults., Methods: Participants were from the Toledo Study for Healthy Aging. We analysed 186 older people aged 67 to 90 (76.7 ± 3.9; 52.7% female participants) over a 4-year period. Time spent in SB and MVPA was assessed by accelerometry. Frailty Trait Scale was used to determine frailty levels. A cross-lagged panel model design was used to test the reciprocal relationships between MVPA/SB and frailty., Results: Frailty Trait Scale score changed from 35.4 to 43.8 points between the two times (P < 0.05). We also found a reduction of 7 min/day in the time spent on MVPA (P < 0.05), and participants tended to spend more time on SB (P = 0.076). Our analyses revealed that lower levels of initial MVPA predicted higher levels of later frailty [std. β = -0.126; confidence interval (CI) = -0.231, -0.021; P < 0.05], whereas initial spent time on SB did not predict later frailty (std. β = -0.049; CI = -0.185, 0.087; P = 0.48). Conversely, an initial increased frailty status predicted higher levels of later SB (std. β = 0.167; CI = 0.026, 0.307; P < 0.05) but not those of MVPA (std. β = 0.071; CI = -0.033, 0.175; P = 0.18)., Conclusions: Our observations suggest that the relationship between MVPA/SB and frailty is unidirectional: individuals who spent less time on MVPA at baseline are more likely to increase their frailty score, and individuals who are more frail are more likely to spent more time on SB at follow-up. Interventions and policies should aim to increase MVPA levels from earlier stages to promote successful aging., (© 2020 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.)

Background: Physical activity and sedentary behaviour have been suggested to independently affect a number of health outcomes. To what extent different combinations of physical activity and sedentary behaviour may influence physical function and frailty outcomes in older adults is unknown. The aim of this study was to examine the combination of mutually exclusive categories of accelerometer-measured physical activity and sedentary time on physical function and frailty in older adults., Methods: 771 older adults (54% women; 76.8 ± 4.9 years) from the Toledo Study for Healthy Aging participated in this cross-sectional study. Physical activity and sedentary time were measured by accelerometry. Physically active was defined as meeting current aerobic guidelines for older adults proposed by the World Health Organization. Low sedentary was defined as residing in the lowest quartile of the light physical activity-to-sedentary time ratio. Participants were then classified into one of four mutually exclusive movement patterns: (1) 'physically active & low sedentary', (2) 'physically active & high sedentary', (3) 'physically inactive & low sedentary', and (4) 'physically inactive & high sedentary'. The Short Physical Performance Battery was used to measure physical function and frailty was assessed using the Frailty Trait Scale., Results: 'Physically active & low sedentary' and 'physically active & high sedentary' individuals had significantly higher levels of physical function (β = 1.73 and β = 1.30 respectively; all p < 0.001) and lower frailty (β = - 13.96 and β = - 8.71 respectively; all p < 0.001) compared to 'physically inactive & high sedentary' participants. Likewise, 'physically inactive & low sedentary' group had significantly lower frailty (β = - 2.50; p = 0.05), but significance was not reached for physical function., Conclusions: We found a dose-response association of the different movement patterns analysed in this study with physical function and frailty. Meeting the physical activity guidelines was associated with the most beneficial physical function and frailty profiles in our sample. Among inactive people, more light intensity relative to sedentary time was associated with better frailty status. These results point out to the possibility of stepwise interventions (i.e. targeting less strenuous activities) to promote successful aging, particularly in inactive older adults.

Oxidative stress is associated with disease severity and limb muscle dysfunction in COPD. Our main goal was to assess the effects of exercise training on systemic oxidative stress and limb muscle dysfunction in older people with COPD. Twenty-nine outpatients with COPD (66-90 years) were randomly assigned to a 12-week exercise training (ET; high-intensity interval training (HIIT) plus power training) or a control (CT; usual care) group. We evaluated mid-thigh muscle cross-sectional area (CSA; computed tomography); vastus lateralis (VL) muscle thickness, pennation angle, and fascicle length (ultrasonography); peak VO 2 uptake (VO 2peak ) and work rate (W peak ) (incremental cardiopulmonary exercise test); rate of force development (RFD); maximal muscle power (P max ; force-velocity testing); systemic oxidative stress (plasma protein carbonylation); and physical performance and quality of life. ET subjects experienced changes in mid-thigh muscle CSA (+4%), VL muscle thickness (+11%) and pennation angle (+19%), VO 2peak (+14%), W peak (+37%), RFD (+32% to 65%), P max (+38% to 51%), sit-to-stand time (-24%), and self-reported health status (+20%) (all P < 0.05). No changes were noted in the CT group (P > 0.05). Protein carbonylation decreased among ET subjects (-27%; P < 0.05), but not in the CT group (P > 0.05). Changes in protein carbonylation were associated with changes in muscle size and pennation angle (r = -0.44 to -0.57), exercise capacity (r = -0.46), muscle strength (r = -0.45), and sit-to-stand performance (r = 0.60) (all P < 0.05). The combination of HIIT and power training improved systemic oxidative stress and limb muscle dysfunction in older people with COPD. Changes in oxidative stress were associated with exercise-induced structural and functional adaptations., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: No consensus exists on how to average data to optimize V ˙ O 2max assessment. Although the V ˙ O 2max value is reduced with larger averaging blocks, no mathematical procedure is available to account for the effect of the length of the averaging block on V ˙ O 2max. AIMS: To determine the effect that the number of breaths or seconds included in the averaging block has on the V ˙ O 2max value and its reproducibility and to develop correction equations to standardize V ˙ O 2max values obtained with different averaging strategies., Methods: Eighty-four subjects performed duplicate incremental tests to exhaustion (IE) in the cycle ergometer and/or treadmill using two metabolic carts (Vyntus and Vmax N29). Rolling breath averages and fixed time averages were calculated from breath-by-breath data from 6 to 60 breaths or seconds., Results: V ˙ O 2max decayed from 6 to 60 breath averages by 10% in low fit ( V ˙ O 2max  < 40 mL kg -1  min -1 ) and 6.7% in trained subjects. The V ˙ O 2max averaged from a similar number of breaths or seconds was highly concordant (CCC > 0.97). There was a linear-log relationship between the number of breaths or seconds in the averaging block and V ˙ O 2max (R 2  > 0.99, P < 0.001), and specific equations were developed to standardize V ˙ O 2max values to a fixed number of breaths or seconds. Reproducibility was higher in trained than low-fit subjects and not influenced by the averaging strategy, exercise mode, maximal respiratory rate, or IE protocol., Conclusions: The V ˙ O 2max decreases following a linear-log function with the number of breaths or seconds included in the averaging block and can be corrected with specific equations as those developed here., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Introduction and Purpose: Physical activity (PA) is considered the best nonpharmacological treatment for the decrease in bone mass (BM) produced during aging. Therefore, it is essential to assess how the time spent in PA is distributed to control further changes. This work examines the relationship between movement behaviors and BM during aging, using compositional data analysis., Methods: We studied 227 older people 65 to 94 yr old (102 men and 125 women), divided by sex and bone status, over a period of 4 yr. Time spent in sedentary behavior (SB), light PA (LPA), and moderate to vigorous PA (MVPA), was assessed using accelerometry. BM was determined by dual-energy x-ray absorptiometry., Results: The changes in MVPA were positively associated with the rate of BM decay at spine and leg in the whole sample and men's subgroup (P ≤ 0.05). In women, the rate of BM decay at spine and Ward's triangle were negatively associated with SB changes, and BM decay at femoral neck and Ward's triangle were positively associated with LPA (P ≤ 0.05)., Conclusion: Increasing MVPA related to other movement behaviors produces improvements in the rate of bone change in older men, whereas to increase LPA and maintain MVPA would be the best approach to enhance BM in older women.

Objectives: To determine whether or not and to what extent the association between sedentary time and frailty was moderated by moderate-to-vigorous physical activity in older adults., Design: Cross-sectional., Setting: Community-dwelling individuals., Participants: 749 (403 females and 346 males) white older adults., Measurements: Sedentary time and moderate-to-vigorous physical activity were measured with accelerometers. Frailty was objectively measured using the Frailty Trait Scale. All models were adjusted for age, sex, education, income, marital status, body mass index, moderate-to-vigorous physical activity, and accelerometer wear time., Results: The regression model reported a significant effect of sedentary time on frailty (P < .05). Nevertheless, the results indicated that moderate-to-vigorous physical activity moderates the relationship between frailty status and sedentary time. The Johnson-Neyman technique determined that the estimated moderate-to-vigorous physical activity point was 27.25 minutes/d, from which sedentary time has no significant effect on frailty., Conclusions: Moderate-to-vigorous physical activity is a moderator in the relationship between sedentary time and frailty in older adults, offsetting the harmful effects of sedentary behavior with 27 minutes/d of moderate-to-vigorous activity. Engaging in moderate-to-vigorous physical activities should be encouraged. Reducing sedentary behavior may also be beneficial, particularly among inactive older adults., (Copyright © 2018 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.)

This study aimed to evaluate the effect of the stretch-shortening cycle (SSC) on different portions of the force-velocity (F-V) relationship in older adults with and without chronic obstructive pulmonary disease (COPD), and to assess its association with physical function. The participants were 26 older adults with COPD (79 ± 7 years old; FEV 1 = 53 ± 36% of predicted) and 10 physically active non-COPD (77 ± 4 years old) older adults. The F-V relationship was evaluated in the leg press exercise during a purely concentric muscle action and compared with that following an eccentric muscle action at 10% intervals of maximal unloaded shortening velocity (V 0 ). Vastus lateralis (VL) muscle thickness, pennation angle (PA), and fascicle length (FL) were assessed by ultrasound. Habitual gait speed was measured over a 4-m distance. COPD subjects exhibited lower physical function and concentric maximal muscle power (P max ) values compared with the non-COPD group (both p < 0.05). The SSC increased force and power values among COPD participants at 0-100 and 1-100% of V 0 , respectively, while the same was observed among non-COPD participants only at 40-90 and 30-90% of V 0 , respectively (all p < 0.05). The SSC induced greater improvements in force, but not power, among COPD compared with non-COPD subjects between 50 and 70% of V 0 (all p < 0.05). Thus, between-group differences in muscle power were not statistically significant after the inclusion of the SSC ( p > 0.05). The SSC-induced potentiation at 50-100% of V 0 was negatively associated with physical function ( r = -0.40-0.50), while that observed at 80-100% of V 0 was negatively associated with VL muscle thickness and PA ( r = -0.43-0.52) (all p < 0.05). In conclusion, older adults with COPD showed a higher SSC-induced potentiation compared with non-COPD subjects, which eliminated between-group differences in muscle power when performing SSC muscle actions. The SSC-induced potentiation was associated with lower physical function, VL muscle thickness, and VL PA values. The SSC-induced potentiation may help as a compensatory mechanism in those older subjects with a decreased ability to produce force/power during purely concentric muscle actions.

The aim of this study was to determine the relationship between bone mass (BM) and physical activity (PA) and sedentary behavior (SB) according to frailty status and sex using compositional data analysis. We analyzed 871 older people with an adequate nutritional status. Fried criteria were used to classify by frailty status. Time spent in SB, light intensity PA (LPA) and moderate-to-vigorous intensity PA (MVPA) was assessed from accelerometry for 7 days. BM was determined by dual-energy X-ray absorptiometry (DXA). The combined effect of PA and SB was significantly associated with BM in robust men and women ( p ≤ 0.05). In relation to the other behaviors, SB was negatively associated with BM in robust men while BM was positively associated with SB and negatively with LPA and MVPA in robust women. Moreover, LPA also was positively associated with arm BM ( p ≤ 0.01). Finally, in pre-frail women, BM was positively associated with MVPA. In our sample, to decrease SB could be a good strategy to improve BM in robust men. In contrast, in pre-frail women, MVPA may be an important factor to consider regarding bone health.

Objectives: The aim was to establish whether a short supervised facility-based exercise program improved frailty, physical function and performance in comparison with usual care treatment., Methods: This was a quasi-experimental, non-randomized controlled intervention study in frail (2.75 ± 1.25 Frailty Phenotype criteria) older adults (range:77.2-95.8 years). The exercise (EX) group (n = 11) performed concurrent training (power training + high-intensity interval training, HIIT) twice weekly for 6 weeks while the control (CT) group (n = 9) followed usual care., Results: The exercise intervention improved frailty status in 64% of the subjects improving Frailty Phenotype by 1.6 points (95%CI 0.8-2.5, p < 0.05), and increasing SPPB score by 3.2 points (95%CI: 2.4-4.0, Cohen's d = 2.0, p < 0.05), muscle power by 47% (95%CI: 7-87%, Cohen's d = 0.5, p < 0.05), muscle strength by 34%(95%CI: 7-60, Cohen's d = 0.6, p < 0.05) and the aerobic capacity by 19% (6 minute walking test +45 m, 95%CI: 7-83, Cohen's d = 0.7, p = 0.054). The CT did not experience any significant changes in frailty status, physical function or performance., Conclusions: A short concurrent exercise program of muscle power and walking-based HIIT training is a feasible and safe method to increase physical performance and improve function and frailty in elder (pre)frail patients., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Introduction: Aging is associated with a progressive decrease in bone mass (BM), and being physical active is one of the main strategies to combat this continuous loss. Nonetheless, because daily time is limited, time spent on each movement behavior is co-dependent. The aim of this study was to determine the relationship between BM and movement behaviors in elderly people using compositional data analysis., Methods: We analyzed 871 older people [395 men (76.9±5.3y) and 476 women (76.7±4.7y)]. Time spent in sedentary behavior (SB), light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA), was assessed using accelerometry. BM was determined by bone densitometry (DXA). The sample was divided according to sex and bone health indicators., Results: The combined effect of all movement behaviors (PA and SB) was significantly associated with whole body, leg and femoral region BM in the whole sample (p≤0.05), with leg and pelvic BM (p<0.05) in men and, with whole body, arm and leg BM (p<0.05) in women. In men, arm and pelvic BM were negatively associated with SB and whole body, pelvic and leg BM were positively associated with MVPA (p≤0.05). In women, whole body and leg BM were positively associated with SB. Arm and whole body BM were positively associated and leg BM was negatively associated with LPA and arm BM was negatively associated with MVPA (p≤0.05). Women without bone fractures spent less time in SB and more in LPA and MVPA than the subgroup with bone fractures., Conclusion: We identified that the positive effect of MVPA relative to the other behaviors on bone mass is the strongest overall effect in men. Furthermore, women might decrease bone fracture risk through PA increase and SB reduction, despite the fact that no clear benefits of PA for bone mass were found., Competing Interests: The authors have declared that no competing interests exist.

Introduction: Skeletal muscle power has been demonstrated to be a stronger predictor of functional limitations than any other physical capability. However, no validated alternatives exist to the usually expensive instruments and/or time-consuming methods to evaluate muscle power in older populations. Our aim was to validate an easily applicable procedure to assess muscle power in large cohort studies and the clinical setting and to assess its association with other age-related outcomes., Methods: Forty community dwelling older adults (70-87 years) and 1804 older subjects (67-101 years) participating in the Toledo Study for Healthy Aging were included in this investigation. Sit-to-stand (STS) velocity and muscle power were calculated using the subject's body mass and height, chair height and the time needed to complete five STS repetitions, and compared with those obtained in the leg press exercise using a linear position transducer. In addition, STS performance, physical (gait speed) and cognitive function, sarcopenia (skeletal muscle index (SMI)) and health-related quality of life (HRQoL) were recorded to assess the association with the STS muscle power values., Results: No significant differences were found between STS velocity and power values and those obtained from the leg press force-velocity measurements (mean difference ± 95% CI = 0.02 ± 0.05 m·s -1 and 6.9 ± 29.8 W, respectively) (both p > 0.05). STS muscle power was strongly associated with maximal muscle power registered in the leg press exercise (r = 0.72; p < 0.001). In addition, cognitive function and SMI, and physical function, were better associated with absolute and relative STS muscle power, respectively, than STS time values after adjusting by different covariates. In contrast, STS time was slightly more associated with HRQoL than STS muscle power measures., Conclusion: The STS muscle power test proved to be a valid, and in general, a more clinically relevant tool to assess functional trajectory in older people compared to traditional STS time values. The low time, space and material requirements of the STS muscle power test, make this test an excellent choice for its application in large cohort studies and the clinical setting., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Introduction: The actual mechanisms leading to a reduced muscle power and functional ability in older adults are poorly understood. We investigated the association between different force-velocity (F-V) profiles and impaired muscle power, physical and cognitive function, frailty, and health-related quality of life (HRQoL) in older people., Methods: Physical function (habitual gait speed, timed up-and-go test, sit-to-stand and stair-climbing ability), cognitive function, HRQoL and frailty were evaluated in 31 older subjects (70-85 years). The F-V relationship and maximal muscle power (P max ) were assessed in the leg press exercise. The skeletal muscle index (SMI) and fat index, moderate-to-vigorous physical activity (MVPA) and sedentary time were obtained from DXA scans and accelerometry, respectively., Results: While some subjects showed a force deficit (F DEF ), others presented a velocity deficit (V DEF ), both leading to an impaired muscle power [Effect size (ES) = 1.30-1.44], and to a likely-very likely moderate harmful effect in their physical and cognitive function, HRQoL and frailty levels (except the V DEF group for cognitive function) [ES = 0.76-1.05]. Leg muscle mass and specific force were similarly associated with force at P max , while MVPA but not sedentary time was related to fat index, force at P max , and power values (all p < 0.05). A trend was found for the negative association between fat index and relative P max (p = 0.075)., Conclusion: Older subjects exhibited different mechanisms (force vs. velocity deficits) leading to impaired muscle power. Both deficits were associated with a lower physical function and quality of life, and a higher frailty, whereas only a force deficit was associated with a lower cognitive function. Interventions aimed at reversing age- and/or disuse-related impairments of muscle power might evaluate the specific responsible mechanism and act accordingly., (Copyright © 2018 Elsevier Inc. All rights reserved.)

In obesity, leptin receptors (OBR) and leptin signaling in skeletal muscle are downregulated. To determine whether OBR and leptin signaling are upregulated with a severe energy deficit, 15 overweight men were assessed before the intervention (PRE), after 4 days of caloric restriction (3.2 kcal·kg body wt -1 ·day -1 ) in combination with prolonged exercise (CRE; 8 h walking + 45 min single-arm cranking/day) to induce an energy deficit of ~5,500 kcal/day, and following 3 days of control diet (isoenergetic) and reduced exercise (CD). During CRE, the diet consisted solely of whey protein ( n = 8) or sucrose ( n = 7; 0.8 g·kg body wt -1 ·day -1 ). Muscle biopsies were obtained from the exercised and the nonexercised deltoid muscles and from the vastus lateralis. From PRE to CRE, serum glucose, insulin, and leptin were reduced. OBR expression was augmented in all examined muscles associated with increased maximal fat oxidation. Compared with PRE, after CD, phospho-Tyr 1141 OBR, phospho-Tyr 985 OBR, JAK2, and phospho-Tyr 1007/1008 JAK2 protein expression were increased in all muscles, whereas STAT3 and phospho-Tyr 705 STAT3 were increased only in the arms. The expression of protein tyrosine phosphatase 1B (PTP1B) in skeletal muscle was increased by 18 and 45% after CRE and CD, respectively ( P < 0.05). Suppressor of cytokine signaling 3 (SOCS3) tended to increase in the legs and decrease in the arm muscles (ANOVA interaction: P < 0.05). Myosin heavy chain I isoform was associated with OBR protein expression ( r  = -0.75), phospho-Tyr 985 OBR ( r  = 0.88), and phospho-Tyr 705 STAT3/STAT3 ( r = 0.74). In summary, despite increased PTP1B expression, skeletal muscle OBR and signaling are upregulated by a severe energy deficit with greater response in the arm than in the legs likely due to SOCS3 upregulation in the leg muscles. NEW & NOTEWORTHY This study shows that the skeletal muscle leptin receptors and their corresponding signaling cascade are upregulated in response to a severe energy deficit, contributing to increase maximal fat oxidation. The responses are more prominent in the arm muscles than in the legs but partly blunted by whey protein ingestion and high volume of exercise. This occurs despite an increase of protein tyrosine phosphatase 1B protein expression, a known inhibitor of insulin and leptin signaling., (Copyright © 2017 the American Physiological Society.)

Introduction: Frailty is a strong predictor of adverse health events, but its impact on cognitive function is poorly understood., Aim: To assess cognitive performance in frailty and to identify the frailty stage where cognitive impairment begins., Methods: Data were taken from 2044 people aged ≥65 years without cognitive impairment selected from the Toledo Study for Healthy Aging, a population-based cohort of older adults. Frailty status was assessed by 3 different scales: Frailty Phenotype (FP), Frailty Trait Scale (FTS), and Frailty Index (FI). Neuropsychological assessments of different cognitive domains included the Mini-Mental State Examination, Short and Long-Term Memory Recalling Test, the Boston Naming Test, Verbal Fluency Test, Digit Span Forward, Go/No-go Test, Luria Orders Test, Clock Drawing Test, and Serial Word Learning Test. The relationships between the score of the scales and frailty status (robust, prefrail, and frail for FP and quartiles for FTS and FI) were analyzed using multivariate linear regression models including age, sex, and educative level as possible confounders., Results: Participants classified as the worst degree of frailty (frail in FP and fourth quartile of FTS and FI) presented more cognitive domains affected and to a higher extent than moderate frail (prefrail and second quartile and third quartile of FTS and FI) and robust (and first quartile of FTS and FI) participants., Conclusions: Cognitive performance progressively declined across the frailty state, regardless of the instrument used to assess frailty. In prefrail participants, cognitive impairment may be an early marker of frailty-dependent cerebral involvement and could be already subject to interventions aimed at reducing the transition to frailty., (Copyright © 2017 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.)

End-tidal PCO2 (PET CO2 ) has been used to estimate arterial pressure CO2 (Pa CO2 ). However, the influence of blood temperature on the Pa CO2 has not been taken into account. Moreover, there is no equation validated to predict Pa CO2 during exercise in severe acute hypoxia. To develop a new equation to predict temperature-corrected Pa CO2 values during exercise in normoxia and severe acute hypoxia, 11 volunteers (21.2 ± 2.1 years) performed incremental exercise to exhaustion in normoxia (Nox, PI O2 : 143 mmHg) and hypoxia (Hyp, PI O2 : 73 mmHg), while arterial blood gases and temperature (ABT) were simultaneously measured together with end-tidal PCO2 (PET CO2 ). The Jones et al. equation tended to underestimate the temperature corrected (tc) Pa CO2 during exercise in hypoxia, with greater deviation the lower the Pa CO2 tc (r = 0.39, P < 0.05). The new equation has been developed using a random-effects regression analysis model, which allows predicting Pa CO2 tc both in normoxia and hypoxia: Pa CO2 tc = 8.607 + 0.716 × PET CO2 [R(2)  = 0.91; intercept SE = 1.022 (P < 0.001) and slope SE = 0.027 (P < 0.001)]. This equation may prove useful in noninvasive studies of brain hemodynamics, where an accurate estimation of Pa CO2 is needed to calculate the end-tidal-to-arterial PCO2 difference, which can be used as an index of pulmonary gas exchange efficiency., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)