Long-Term Effects of a 6-Week Power-Based Resistance Training and Fast Walking Interval Training Program on Physical Function, Muscle Power, Disability, and Frailty in Pre-Frail and Frail Older Adults.

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 (>75 years old; Frailty Phenotype >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 < 0.001), relative STS power (∆ = 0.87 W·kg-1; p < 0.001) and reduced their frailty levels (∆ = -1.42 criteria; p < 0.001), while no changes were observed in CON. After 6 months of detraining (∆ = DET-PRE), INT showed higher SPPB (∆ = 2.2 points; p < 0.001), higher relative STS power (∆ = 0.73 W·kg-1; p < 0.001) and lower frailty (∆ = -1.24 criteria; p < 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.

Power-oriented resistance training combined with high-intensity interval training in pre-frail and frail older people: comparison between traditional and cluster training set configurations on the force-velocity relationship, physical function and frailty.

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 (F0, V0 and Pmax), 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 Pmax after training (CT = + 36.7 ± 34.2 W; TT = + 33.8 ± 44.6 W; both p < 0.01). V0 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). F0 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 Pmax, 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.

Vastus Lateralis Muscle Size Is Differently Associated With the Different Regions of the Squat Force-Velocity and Load-Velocity Relationships, Rate of Force Development, and Physical Performance Young Men.

ABSTRACT: Cornejo-Daza, PJ, Sánchez-Valdepeñas, J, Rodiles-Guerrero, L, Páez-Maldonado, JA, Ara, I, León-Prados, JA, Alegre, LM, Pareja-Blanco, F, and Alcazar, J. Vastus lateralis muscle size is differently associated with the different regions of the squat force-velocity and load-velocity relationships, rate of force development, and physical performance young men. J Strength Cond Res 38(3): 450-458, 2024-The influence that regional muscle size and muscle volume may have on different portions of the force-velocity (F-V) and load-velocity (L-V) relationships, explosive force, and muscle function of the lower limbs is poorly understood. This study assessed the association of muscle size with the F-V and L-V relationships, rate of force development (RFD) and maximal isometric force in the squat exercise, and vertical jump performance via countermovement jump (CMJ) height. Forty-nine resistance-trained young men (22.7 ± 3.3 years old) participated in the study. Anatomical cross-sectional area (ACSA) of the vastus lateralis (VLA) muscle was measured using the extended field of view mode in an ultrasound device at 3 different femur lengths (40% [distal], 57.5% [medial], and 75% [proximal]), and muscle volume was estimated considering the VLA muscle insertion points previously published and validated in this study. There were significant associations between all muscle size measures (except distal ACSA) and (a) forces and loads yielded at velocities ranging from 0 to 1.5 m·s -1 ( r = 0.36-0.74, p < 0.05), (b) velocities exerted at forces and loads ranging between 750-2,000 N and 75-200 kg, respectively ( r = 0.31-0.69, p < 0.05), and (c) RFD at 200 and 400 milliseconds ( r = 0.35-0.64, p < 0.05). Proximal and distal ACSA and muscle volume were significantly associated with CMJ height ( r = 0.32-0.51, p < 0.05). Vastus lateralis muscle size exhibited a greater influence on performance at higher forces or loads and lower velocities and late phases of explosive muscle actions. Additionally, proximal ACSA and muscle volume showed the highest correlation with the muscle function measures.

Residual effects of 12 weeks of power-oriented resistance training plus high-intensity interval training on muscle dysfunction, systemic oxidative damage, and antioxidant capacity after 10 months of training cessation in older people with COPD.

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 VO2 ) and peak work rate (Wpeak ), early and late isometric rate of force development (RFD), leg and chest press maximum muscle power (LPmax and CPmax ), 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 ), LPmax (∆ = 62.2 W), and CPmax (∆ = 16.0 W) (all p < 0.05). In addition, a positive effect was noted in INT compared to CON regarding MT and Wpeak (both p < 0.05). No between-group differences were reported in peak VO2 , 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 Wpeak but not peak VO2 , late RFD, systemic oxidative damage and antioxidant capacity in the subsequent 10 months of detraining in older adults with COPD.

Neuromuscular adaptations after 12 weeks of light- vs. heavy-load power-oriented resistance training in older adults.

This study aimed to determine the specific adaptations provoked by power-oriented resistance training using light (LL-PT, 40% 1-RM) vs. heavy (HL-PT, 80% 1-RM) loads in older adults. Using a randomized within-subject study design, 45 older adults (>65 years) completed an 8-week control period (CTR) followed by 12 weeks of unilateral LL-PT vs. HL-PT on a leg press. The 1-RM, theoretical force at zero velocity (F0 ), maximal unloaded velocity (V0 ), and maximal muscle power (Pmax ) were determined through a force-velocity relationship test. Isometrically, the rate of force development (RFD) and the corresponding muscle excitation of the knee extensor muscles were assessed. In addition, muscle cross-sectional area (CSA) and architecture of two quadriceps muscles were determined. Changes after CTR, LL-PT and HL-PT were compared using linear mixed models. HL-PT provoked greater improvements in 1-RM and F0 (effect size (ES) = 0.55-0.68; p < 0.001) than those observed after LL-PT (ES = 0.27-0.47; p ≤ 0.001) (post hoc treatment effect, p ≤ 0.057). By contrast, ES of changes in V0 was greater in LL-PT compared to HL-PT (ES = 0.71, p < 0.001 vs. ES = 0.39, p < 0.001), but this difference was not statistically significant. Both power training interventions elicited a moderate increase in Pmax (ES = 0.65-0.69, p < 0.001). Only LL-PT improved early RFD (ie, ≤100 ms) and muscle excitation (ES = 0.36-0.60, p < 0.05). Increased CSA were noted after both power training programs (ES = 0.13-0.35, p < 0.035), whereas pennation angle increased only after HL-PT (ES = 0.37, p = 0.004). In conclusion, HL-PT seems to be more effective in improving the capability to generate large forces, whereas LL-PT appears to trigger greater gains in movement velocity in older adults. However, both interventions promoted similar increases in muscle power as well as muscle hypertrophy.

A novel equation that incorporates the linear and hyperbolic nature of the force-velocity relationship in lower and upper limb exercises.

The purpose of this study is to provide a force-velocity (F-V) equation that combines a linear and a hyperbolic region, and to compare its derived results to those obtained from linear equations. A total of 10 cross-training athletes and 14 recreationally resistance-trained young men were assessed in the unilateral leg press (LP) and bilateral bench press (BP) exercises, respectively. F-V data were recorded using a force plate and a linear encoder. Estimated maximum isometric force (F0), maximum muscle power (Pmax), and maximum unloaded velocity (V0) were calculated using a hybrid (linear and hyperbolic) equation and three different linear equations: one derived from the hybrid equation (linearhyb), one applied to data from 0 to 100% of F0 (linear0-100), and one applied to data from 45 to 100% of F0 (linear45-100). The hybrid equation presented the best fit to the recorded data (R2 = 0.996 and 0.998). Compared to the results derived from the hybrid equation in the LP, significant differences were observed in F0 derived from linear0-100; V0 derived from linearhyb, linear0-100 and linear45-100; and Pmax derived from linearhyb and linear45-100 (all p < 0.05). For the BP, compared to the hybrid equation, significant differences were found in F0 derived from linear0-100; and V0 and Pmax derived from linearhyb, linear0-100 and linear45-100 (all p < 0.05). An F-V equation combining a linear and a hyperbolic region showed to fit adequately recorded F-V data from ~ 20 to 100% of F0, and overcame the limitations shown by linear equations while providing relevant results.

Mechanical Characteristics of Heavy vs. Light Load Ballistic Resistance Training in Older Adults.

ABSTRACT: Rodriguez-Lopez, C, Alcazar, J, Sánchez-Martín, C, Ara, I, Csapo, R, and Alegre, LM. Mechanical characteristics in heavy vs. light load ballistic resistance training in older adults. J Strength Cond Res 36(8): 2094-2101, 2022-Although power-oriented resistance training (RT) is strongly recommended to counter age-related neuromuscular function declines, there is still controversy about which intensities of load should be used to elicit optimal training adaptations. Knowledge of the mechanical characteristics of power-oriented RT performed at different intensities might help to better understand the training stimulus that triggers load-dependent adaptations in older adults. Using a cross-over design, 15 well-functioning older volunteers (9 men and 6 women; 73.6 ± 3.8 years) completed 2 volume × load-matched ballistic RT sessions with heavy (HL: 6 × 6 × 80% 1-repetition maximum [1RM]) and light-load (LL: 6 × 12 × 40% 1RM) on a horizontal leg press exercise. Electromyographic (EMG) and mechanical variables (work, force, velocity, and power) as well as intraset neuromuscular fatigue (i.e., relative losses in force, velocity, and power) were analyzed. More concentric mechanical work was performed in the LL training session, compared with HL (36.2 ± 11.2%; p < 0.001). Despite the higher mean EMG activity of the quadriceps femoris muscle (13.2 ± 21.1%; p = 0.038) and greater concentric force (35.2 ± 7.6%; p < 0.001) during HL, higher concentric velocity (41.0 ± 12.7%, p < 0.001) and a trend toward higher concentric power (7.2 ± 18.9%, p = 0.075) were found for LL. Relative velocity losses were similar in both sessions (≈10%); however, relative force losses were only found in LL (7.4 ± 6.5%, p = 0.003). Considering the greater mechanical work performed and concentric power generated, ballistic RT using LL may, therefore, represent a stronger stimulus driving training adaptations as compared with volume × load-matched heavy-load training. Relative losses in force and power should be monitored in addition to velocity losses during ballistic RT.

'Fat but powerful' paradox: association of muscle power and adiposity markers with all-cause mortality in older adults from the EXERNET multicentre study.

OBJECTIVES: To assess the influence of muscle power and adiposity on all-cause mortality risk and to evaluate the 'fat but powerful' (F+P) (or 'fat but fit') paradox in older adults. METHODS: A total of 2563 older adults (65‒91 years old) from the EXERNET multicentre study were included. Adiposity (body mass index (BMI), waist circumference, body fat percentage (BF%) and fat index), allometric and relative power (sit-to-stand muscle power test) and various covariates (age, sex, hypertension, smoking status and walking and sitting times per day) were registered at baseline. All-cause mortality was recorded during a median follow-up of 8.9 years. Participants were classified into four groups: lean and powerful (L+P), F+P, lean but weak and fat and weak (F+W). Cox proportional hazard regression models and adjusted HRs were calculated. RESULTS: According to BMI and waist circumference, all-cause mortality risk was reduced in the F+P (HR=0.55 and 0.63, p=0.044 and 0.049, respectively) and L+P (HR=0.57 and 0.58, p=0.043 and 0.025, respectively) groups. According to BF%, all-cause mortality decreased in the L+P group (HR=0.53; p=0.021), and a trend for a reduction was reported in the F+P group (HR=0.57; p=0.060). According to fat index, a survival benefit was only noted in the L+P group (HR=0.50; p=0.049). Higher levels of relative power reduced all-cause mortality risk among older people (HR=0.63 and 0.53, p=0.006 and 0.011, respectively). CONCLUSION: Powerful older people exhibited a reduced 9-year all-cause mortality regardless of BMI, waist circumference and BF%. Obesity according to fat index blunted the survival benefits of being powerful.

Acute Physiological Response to Light- and Heavy-load Power-oriented Exercise in Older Adults.

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.

Effects of velocity loss in the bench press exercise on strength gains, neuromuscular adaptations, and muscle hypertrophy.

OBJECTIVE: This study aimed to compare the effects of four velocity-based training (VBT) programs in bench press (BP) between a wide range of velocity loss (VL) thresholds-0% (VL0), 15% (VL15), 25% (VL25), and 50% (VL50)-on strength gains, neuromuscular adaptations, and muscle hypertrophy. METHODS: Sixty-four resistance-trained young men were randomly assigned into four groups (VL0, VL15, VL25, and VL50) that differed in the VL allowed in each set. Subjects followed a VBT program for 8-weeks using the BP exercise. Before and after the VBT program the following tests were performed: (a) cross-sectional area (CSA) measurements of pectoralis major (PM) muscle; (b) maximal isometric test; (c) progressive loading test; and (d) fatigue test. RESULTS: Significant group x time interactions were observed for CSA (P < .01) and peak root mean square in PM (peak RMS-PM, P < .05). VL50 showed significantly greater gains in CSA than VL0 (P < .05). Only the VL15 group showed significant increases in peak RMS-PM (P < .01). Moreover, only VL0 showed significant gains in the early rate of force development (RFD, P = .05), while VL25 and VL50 improved in the late RFD (P ≤ .01-.05). No significant group × time interactions were found for any of the dynamic strength variables analyzed, although all groups showed significant improvements in all these parameters. CONCLUSION: Higher VL thresholds allowed for a greater volume load which maximized muscle hypertrophy, whereas lower VL thresholds evoked positive neuromuscular-related adaptations. No significant differences were found between groups for strength gains, despite the wide differences in the total volume accumulated by each group.

Effects of concurrent exercise training on muscle dysfunction and systemic oxidative stress in older people with COPD.

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 VO2 uptake (VO2peak ) and work rate (Wpeak ) (incremental cardiopulmonary exercise test); rate of force development (RFD); maximal muscle power (Pmax ; 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%), VO2peak (+14%), Wpeak (+37%), RFD (+32% to 65%), Pmax (+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.

Validation of Field Methods to Assess Body Fat Percentage in Elite Youth Soccer Players.

This study determined the most effective field method for quantifying body fat percentage in male elite youth soccer players and developed prediction equations based on anthropometric variables. Forty-four male elite-standard youth soccer players aged 16.3-18.0 years underwent body fat percentage assessments, including bioelectrical impedance analysis and the calculation of various skinfold-based prediction equations. Dual X-ray absorptiometry provided a criterion measure of body fat percentage. Correlation coefficients, bias, limits of agreement, and differences were used as validity measures, and regression analyses were used to develop soccer-specific prediction equations. The equations from Sarria et al. (1998) and Durnin & Rahaman (1967) reached very large correlations and the lowest biases, and they reached neither the practically worthwhile difference nor the substantial difference between methods. The new youth soccer-specific skinfold equation included a combination of triceps and supraspinale skinfolds. None of the practical methods compared in this study are adequate for estimating body fat percentage in male elite youth soccer players, except for the equations from Sarria et al. (1998) and Durnin & Rahaman (1967). The new youth soccer-specific equation calculated in this investigation is the only field method specifically developed and validated in elite male players, and it shows potentially good predictive power.

The Force-Velocity Relationship in Older People: Reliability and Validity of a Systematic Procedure.

This study compared the reliability and validity of different protocols evaluating the force-velocity (F-V) relationship and muscle power in older adults. Thirty-one older men and women (75.8±4.7 years) underwent two F-V tests by collecting the mean and peak force and velocity data exerted against increasing loads until one repetition maximum (1RM) was achieved in the leg press exercise. Two attempts per load were performed, with a third attempt when F-V points deviated from the linear F-V regression equation. Then, the subjects performed 2×3 repetitions at 60% 1RM to compare purely concentric and eccentric-concentric repetitions. The Short Physical Performance Battery was conducted to assess the validity of the different protocols. Significant differences were found in maximal power (Pmax) between mean and peak values and between protocols differing in the number of attempts per load (p<0.01). Registering mean values, a third attempt, and multiple loads (>3), was significantly more reliable (Pmax: CV=2.6%; ICC=0.99) than the other alternatives. Mean values were also observed to be more associated with physical function than peak values (R2=0.34 and 0.15, respectively; p<0.05). No significant differences were observed between concentric and eccentric-concentric repetitions. Thus, collecting mean force and velocity values against multiple loads, while monitoring the linearity of the F-V relationship, seemed to be the more adequate procedure to assess the F-V profile and muscle power in older adults.

Short- and Long-Term Effects of Concurrent Strength and HIIT Training in Octogenarians with COPD.

To investigate the short- and long-term effects of concurrent strength and high-intensity interval training (HIIT) on octogenarian COPD patients, nine males (age = 84.2 ± 2.8 years, BMI = 29.3 ± 2.3) with low to severe COPD levels (2.1 ± 1.5 BODE index) underwent a supervised 9-week strength and HIIT exercise program. Training had a significant (p < .05) impact on senior fitness test scores (23-45%), 30-m walking speed (from 1.29 ± 0.29-1.62 ± 0.33 m/s), leg and chest press 1RM (38% and 45% respectively), maximal isometric strength (30-35%), and 6-min walking test (from 286.1 ± 107.2-396.2 ± 106.5 m), and tended to increase predicted forced vital capacity by 14% (p = .07). One year after the intervention all training-induced gains returned to their preintervention values except for the chest press 1RM (p <.05). Short-term concurrent strength and HIIT training increases physical fitness in the oldest-old COPD patients, and has potential long-term benefits.

Effects of multicomponent training and HMB supplementation on disability, cognitive and physical function in institutionalized older adults aged over 70 years: a cluster-randomized controlled trial.

OBJECTIVES: To investigate the synergist effects of exercise and ß-hydroxy ß-methylbutyrate (HMB) supplementation on disability, cognitive and physical function, and muscle power in institutionalized older people. DESIGN: Cluster-randomized controlled trial. PARTICIPANTS: Seventy-two institutionalized older adults (age = 83 ± 10 years old; 63% women) were randomized in four groups: exercise plus placebo (EX), HMB supplementation, EX plus HMB supplementation (EX + HMB), and control (CT). INTERVENTION: The exercising participants completed a 12-week tailored multicomponent exercise intervention (Vivifrail; 5 days/week of an individualized resistance, cardiovascular, balance and flexibility program), whereas the HMB groups received a drink containing 3 g/day of HMB. MEASUREMENTS: Participants were assessed Pre and Post intervention for disability and cognitive function (validated questionnaires), physical function (short physical performance battery, SPPB), handgrip strength and sit-to-stand relative muscle power. Linear mixed-effect models were used to compare changes among groups. RESULTS: Compared to baseline, both EX and EX + HMB improved cognitive function (+2.9 and +1.9 points; p < 0.001), SPPB score (+2.9 points and +2.4 points; p < 0.001) and relative muscle power (+0.64 and +0.48 W·kg-1; p < 0.001), while CT and HMB remained unchanged (p > 0.05). Significant between-group differences were noted between CT, EX and EX + HMB for cognitive function (p < 0.01), between CT and EX + HMB for physical function (p = 0.043), and between CT, EX and EX + HMB for relative muscle power (p < 0.001). CONCLUSION: The Vivifrail exercise program was effective in improving cognitive and physical function, and muscle power in nursing home residents, while HMB supplementation did not provide additional benefits when combined with exercise. These results emphasize the importance of physical exercise interventions in very old people as an essential basis for improving their overall health and quality of life.

Ten-year longitudinal changes in muscle power, force, and velocity in young, middle-aged, and older adults.

BACKGROUND: Maximum muscle power (Pmax ) is a biomarker of physical performance in all ages. No longitudinal studies have assessed the effects of aging on Pmax obtained from the torque-velocity (T-V) relationship, which should be considered the 'gold standard'. This study evaluated the longitudinal changes in the T-V relationship and Pmax of the knee-extensor muscles in young, middle-aged, and older adults after 10 years of follow-up. METHODS: Four hundred eighty-nine subjects (311 men and 178 women; aged 19-68 years) were tested at baseline and after a 10-year follow-up. Anthropometric data, daily protein intake, physical activity level (PAL), and knee-extension muscle function (isometric, isokinetic, and isotonic) were evaluated. A novel hybrid equation combining a linear and a hyperbolic (Hill-type) region was used to obtain the T-V relationship and Pmax of the participants, who were grouped by sex and age (young: 20-40 years; middle-aged: 40-60 years; and old: ≥60 years). Linear mixed-effect models were used to assess effects of time, sex, and age on T-V parameters, Pmax , and body mass index (BMI). Additional analyses were performed to adjust for changes in daily protein intake and PAL. RESULTS: Pmax decreased in young men (-0.6% per year; P < 0.001), middle-aged men and women (-1.1% to -1.4% per year; P < 0.001), and older men and women (-2.2% to -2.4% per year; P ≤ 0.053). These changes were mainly related to decrements in torque at Pmax at early age and to decrements in both torque and velocity at Pmax at older age. BMI increased among young and middle-aged adults (0.2% to 0.5% per year; P < 0.001), which led to greater declines in relative Pmax in those groups. S/T0 , that is, the linear slope of the T-V relationship relative to maximal torque, exhibited a significant decline over time (-0.10%T0 ·rad·s-1 per year; P < 0.001), which was significant among middle-aged men and old men and women (all P < 0.05). Annual changes in PAL index were significantly associated to annual changes in Pmax (P = 0.017), so the overall decline in Pmax was slightly attenuated in the adjusted model (-5.26 vs. -5.05 W per year; both P < 0.001). CONCLUSIONS: Pmax decreased in young, middle-aged, and older adults after a 10-year follow-up. The early declines in Pmax seemed to coincide with declines in force, whereas the progressive decline at later age was associated with declines in both force and velocity. A progressively blunted ability to produce force, especially at moderate to high movement velocities, should be considered a specific hallmark of aging.

Sensor- and equation-based sit-to-stand power: The effect of age and functional limitations.

Estimating lower-limb muscle power during sit-to-stand (STS) tests is feasible for large-scale implementation. This study investigated 1) whether age, functional limitations and sex have an influence on the movement strategy and power production during STS; and 2) potential differences between STS power estimated with either a simple equation or a sensor. Five-repetition STS data of 649 subjects (♂352 ♀297) aged 19 to 93 years were included. Subjects were divided in different age groups and levels of functioning. A body-fixed sensor measured (sub)durations, trunk movement (flexion/extension) and STS muscle power (Psensor). Additionally, mean STS muscle power was calculated by a mathematic equation (Alcazar et al., 2018b)Results revealed that 1) older subjects and women showed greater trunk flexion before standing up than younger subjects and men, respectively (both p < 0.001); 2) well-functioning adults seemed to have the tendency to not extend the trunk fully during the sit-to-stand transition (mean difference extension - flexion range = -15.3° to -13.1°, p < 0.001); 3) mobility-limited older adults spent more time in the static sitting and standing positions than their well-functioning counterparts (all p < 0.001); 4) STS power decreased with age and was lower in women and in limited-functioning subjects compared to men and well-functioning subjects, respectively (p < 0.05); 5) Pformula was highly related to Psensor (ICC = 0.902, p < 0.001); and 6) Pformula demonstrated higher values than Psensor in well-functioning adults [mean difference = -0.31 W/kg and -0.22 W/kg for men and women, respectively (p < 0.001)], but not among limited-functioning older adults. To conclude, this study showed that age and functional limitations have an influence on the movement strategy during a 5-repetition STS test. Differences in movement strategy can affect the comparison between Pformula and Psensor. In well-functioning older adults, Pformula was slightly higher than Psensor, which might be related to an incomplete extension in the sit-to-stand transition.

Circulating sestrins and force velocity profiling in older adults with type 2 diabetes.

Type 2 diabetes mellitus (T2DM) in old age affects the musculoskeletal system causing loss of muscle mass, strength, and physical function. Stress-inducible proteins named sestrins are potential novel biomarkers of muscle function due to their ability to suppress oxidative stress and prevent muscle degeneration. Our aim was to determine the association between different force-velocity (F-V) profiles with body composition, physical performance, and glucose control in older adults with T2DM. We also intended to determine the potential utility of sestrin 1 (Sesn1) and 2 (Sesn2) as biomarkers of physical functionality. Fifty-nine participants (69-79 years) were classified in 3 groups according to their F-V profile based on the leg press exercise: nondeficit (NDEF = 40.7%), force deficit (FDEF = 28.8%), and velocity deficit (VDEF = 30.5%). Both VDEF and FDEF groups showed lower muscle power than NDEF (Cohen's d 0.87 and 0.75 for effect size, respectively). Serum Sesn2 levels, maximal dynamic strength, arms and legs fat-free mass were reduced in FDEF compared to the NDEF group (p < 0.05), whereas glycated haemoglobin (HbA1c) and fasting glucose levels were similar among groups. ROC analysis revealed the distinction between the NDEF and FDEF group based on Sesn2 concentrations (<0.72 ng/mL), suggesting their potential use as functional biomarkers for early intervention through exercise. Older adults with T2DM show different F-V profiles, related to low levels of Sesn2, impaired body composition and physical performance, and may be taken into consideration to target exercise training in this specific population.Highlights The influence of different F-V deficit profiles on body composition, physical function and circulating sestrins in older adults with type 2 diabetes were studied.Both force and velocity deficits negatively affected muscle power.Force deficits are associated to low circulating sestrin 2 levels and regional fat-free mass.Basal serum sestrin 2 levels are potential biomarkers to characterise F-V profiles.

Relative Sit-to-Stand Muscle Power Predicts an Older Adult's Physical Independence at Age of 90 Yrs Beyond That of Relative Handgrip Strength, Physical Activity, and Sedentary Time: A Cross-sectional Analysis.

OBJECTIVES: Muscle power is important for an older adult's physical independence and can be easily estimated using the sit-to-stand test. This investigation aimed to assess whether muscle power estimated using the sit-to-stand test could identify older adults at risk of losing physical independence beyond handgrip strength, physical activity, and sedentary time and to develop minimal sit-to-stand power thresholds. DESIGN: Physical independence was assessed cross-sectionally in older adults using a composite physical function questionnaire. Muscle power was calculated using the 30-sec sit-to-stand test. Muscle strength was determined using a handgrip dynamometer. Physical activity and sedentary time were assessed by accelerometry. Multiple logistic regression was used to assess the independent association between sit-to-stand power and projected physical independence ( n = 737). Receiver operator characteristic curves were used to develop sit-to-stand power cut points ( N = 1748). RESULTS: Sit-to-stand power proved to be the best predictor of physical independence in later life regardless of handgrip strength, physical activity, and sedentary time (standardized B = 0.45, -0.02, 0.12, -0.28, respectively). Sex- and age-specific cutoffs for sit-to-stand power had good discriminatory ability (area under the curve = 0.75-0.78 [women], 0.76-0.82 [men]). CONCLUSIONS: Sit-to-stand power can be used as a simple and practical screening tool to assess an older adult's future physical independence.

Specific Adaptations to 0%, 15%, 25%, and 50% Velocity-Loss Thresholds During Bench Press Training.

PURPOSE: To compare the effect of 4 velocity-loss (VL) thresholds-0% (VL0), 15% (VL15), 25% (VL25), and 50% (VL50)-on strength gains, neuromuscular adaptations, and muscle hypertrophy during the bench press (BP) exercise using intensities ranging from 55% to 70% of 1-repetition maximum (1RM). METHODS: Fifty resistance-trained men were randomly assigned to 4 groups that followed an 8-week (16 sessions) BP training program at 55% to 70% 1RM but differed in the VL allowed in each set (VL0, VL15, VL25, and VL50). Assessments performed before (pre) and after (post) the training program included (1) cross-sectional area of pectoralis major muscle, (2) maximal isometric test, (3) progressive loading test, and (4) fatigue test in the BP exercise. RESULTS: A significant group × time interaction was found for 1RM (P = .01), where all groups except VL0 showed significant gains in 1RM strength (P < .001). The VL25 group attained the greatest gains in 1RM strength and most load-velocity relationship parameters analyzed. A significant group × time interaction was observed for EMG root mean square in pectoralis major (P = .03) where only the VL25 group showed significant increases (P = .02). VL50 showed decreased EMG root mean square in triceps brachii (P = .006). Only the VL50 group showed significant increases in cross-sectional area (P < .001). CONCLUSIONS: These findings indicate that a VL threshold of about 25% with intensities from 55% to 70% 1RM in BP provides an optimal training stimulus to maximize dynamic strength performance and neuromuscular adaptations, while higher VL thresholds promote higher muscle hypertrophy.