Moderators of Resistance Training Effects in Healthy Young Women: A Systematic Review and Meta-analysis.

ABSTRACT: Molinari, T, Radaelli, R, Rech, A, Brusco, CM, Markarian, AM, and Lopez, P. Moderators of resistance training effects in healthy young women: A systematic review and meta-analysis. J Strength Cond Res 38(4): 804-814, 2024-To systematically review and analyze the effects of resistance-based exercise programs and potential moderators of change in body fat percentage, whole-body fat and lean mass, muscle hypertrophy, muscle strength, and muscle power/rapid force in healthy young women (between 18 and 35 years). A systematic search was undertaken in 7 databases from inception to May 2022. Eligible randomized controlled trials examined the effects of resistance-based exercise programs on outcomes of interest in healthy young women. Meta-analysis was undertaken with a 3-level mixed-effects model. Associations between standardized mean difference (SMD) and potential moderators (number of sessions, weekly volume, and intensity) were tested by meta-regression models. Statistical significance was set at an α level of 0.05, whereas an α level of 0.05-0.10 was also considered for potential moderators of resistance training effects. Forty articles ( n = 1,312) were included. Resistance-based exercise programs resulted in a significant improvement of 0.4 SMD (95% confidence intervals [95% CI]: 0.2 to 0.5, p < 0.001) in lean mass/muscle hypertrophy and 1.2 SMD (95% CI: 0.9 to 1.5, p < 0.001) in muscle strength. A higher number of sessions was associated with changes in lean mass/muscle hypertrophy ( ß = 0.01 ± 0.00, p = 0.009), whereas a higher weekly volume approached statistical significance to moderate changes in muscle strength ( ß = 0.01 ± 0.01, p = 0.053). Body fat percentage (-0.4 SMD, 95% CI: -0.6 to -0.1, p = 0.006) and muscle power/rapid force (0.6 SMD, 95% CI: 0.2 to 1.1, p = 0.011) were significantly improved. In conclusion, a higher resistance training volume was associated with greater improvements in lean mass/muscle hypertrophy, muscle strength, and body fat percentage, whereas muscle power/rapid force improvements were observed irrespective of prescription characteristics. These findings may help in designing resistance training programs for muscle hypertrophy, strength and power, and body fat percentage in healthy women.

Effects of Exercise Training on Muscle Quality in Older Individuals: A Systematic Scoping Review with Meta-Analyses.

BACKGROUND: The quantity and quality of skeletal muscle are important determinants of daily function and metabolic health. Various forms of physical exercise can improve muscle function, but this effect can be inconsistent and has not been systematically examined across the health-neurological disease continuum. The purpose of this systematic scoping review with meta-analyses was to determine the effects and potential moderators of exercise training on morphological and neuromuscular muscle quality (MMQ, NMQ) in healthy older individuals. In addition and in the form of a scoping review, we examined the effects of exercise training on NMQ and MMQ in individuals with neurological conditions. METHODS: A systematic literature search was performed in the electronic databases Medline, Embase, and Web of Science. Randomized controlled trials were included that examined the effects of exercise training on muscle quality (MQ) in older individuals with and without neurological conditions. Risk of bias and study quality were assessed (Cochrane Risk of Bias Tool 2.0). We performed random-effects models using robust variance estimation and tested moderators using the approximate Hotelling-Zhang test. RESULTS: Thirty studies (n = 1494, 34% females) in healthy older individuals and no studies in individuals with neurological conditions were eligible for inclusion. Exercise training had small effects on MMQ (g = 0.21, 95% confidence interval [CI]: 0.03-0.40, p = 0.029). Heterogeneity was low (median I2 = 16%). Training and demographic variables did not moderate the effects of exercise on MMQ. There was no association between changes in MMQ and changes in functional outcomes. Exercise training improved NMQ (g = 0.68, 95% CI 0.35-1.01, p < 0.000) across all studies, in particular in higher-functioning older individuals (g = 0.72, 95% CI 0.38-1.06, p < 0.001), in lower extremity muscles (g = 0.74, 95% CI 0.35-1.13, p = 0.001), and after resistance training (g = 0.91; 95% CI 0.42-1.41, p = 0.001). Heterogeneity was very high (median I2 = 79%). Of the training and demographic variables, only resistance training moderated the exercise-effects on NMQ. High- versus low-intensity exercise moderated the exercise-effects on NMQ, but these effects were considered unreliable due to a low number of studies at high intensity. There was no association between changes in NMQ and changes in functional outcomes. CONCLUSION: Exercise training has small effects on MMQ and medium-large effects on NMQ in healthy older individuals. There was no association between improvements in MQ and increases in muscle strength, mobility, and balance. Information on dose-response relations following training is currently lacking. There is a critical gap in muscle quality data for older individuals with lower function and neurological conditions after exercise training. Health practitioners should use resistance training to improve muscle function in older individuals. Well-designed studies are needed to examine the relevance of exercise training-induced changes in MQ in daily function in older individuals, especially to those with lower function and neurological conditions.

Hamstring Stiffness and Strength Responses to Repeated Sprints in Healthy Nonathletes and Soccer Players With Versus Without Previous Injury.

BACKGROUND: The effect of 10 × 30 m repeated sprints on passive and active stiffness of semitendinosus (ST) and biceps femoris long head (BFlh), and knee flexor maximal voluntary isometric contraction (MVIC) and rate of force development (RFD), and whether athletes with previous hamstring injury have a different response, is unknown. HYPOTHESIS: Repeated sprints would (1) increase BFlh stiffness and decrease ST stiffness and knee flexors MVIC and RFD in healthy participants; and (2) greater magnitude of response would be seen in athletes with previous hamstring injury. STUDY DESIGN: Case series (experiment I) and case control (experiment II) study designs. LEVEL OF EVIDENCE: Level 3. METHODS: Healthy nonathletes attended 2 replicated sessions (experiment I, n = 18), while soccer players with (n = 38) and without (n = 67) previous hamstring injury attended 1 testing session (experiment II). RESULTS: In both experiments, the knee flexors MVIC and RFD decreased after the sprints (P < 0.05). In experiment I, the ST and BFlh passive stiffness reduced after the sprints (P < 0.02), while a small BFlh active stiffness increase was noted (P = 0.02); however, no correlation was observed between the 2 testing sessions for the postsprint muscle stiffness responses (r = -0.07-0.44; P > 0.07). In experiment II, only an ST passive stiffness reduction was observed after the sprints (P < 0.01). No differences were noted between injured and noninjured lower limbs for any variable (P > 0.10). CONCLUSION: Repeated sprints are likely to decrease the knee flexor's maximal and rapid strength, and to alter the hamstring stiffness in the nonathlete population. Previous hamstring injury does not apparently affect the footballer's hamstring functional and mechanical responses to repeated sprints. CLINICAL RELEVANCE: The responses of hamstring stiffness and knee flexor strength to repeated sprints are unlikely to be associated with hamstring injury.

Does High-Velocity Resistance Exercise Elicit Greater Physical Function Benefits Than Traditional Resistance Exercise in Older Adults? A Systematic Review and Network Meta-Analysis of 79 Trials.

BACKGROUND: A systematic review and network meta-analysis was undertaken to examine the effectiveness of different modes of resistance exercise velocity in fast walking speed, timed-up and go, 5-times sit-to-stand, 30-second sit-to-stand, and 6-minute walking tests in older adults. METHODS: CINAHL, Embase, LILACS, PubMed, Scielo, SPORTDiscus, and Web of Science databases were searched up to February 2022. Eligible randomized trials examined the effects of supervised high-velocity or traditional resistance exercise in older adults (ie, ≥60 years). The primary outcome for this review was physical function measured by fast walking speed, timed-up and go, 5-times sit-to-stand, 30-second sit-to-stand, and 6-minute walking tests, while maximal muscle power and muscle strength were secondary. A random-effects network meta-analysis was undertaken to examine the effects of different resistance exercise interventions. RESULTS: Eighty articles describing 79 trials (n = 3 575) were included. High-velocity resistance exercise was the most effective for improving fast walking speed (standardized mean difference [SMD] -0.44, 95% confidence interval [CI]: 0.00 to 0.87), timed-up and go (SMD -0.76, 95% CI: -1.05 to -0.47), and 5-times sit-to-stand (SMD -0.74, 95% CI: -1.20 to -0.27), while traditional resistance exercise was the most effective for 30-second sit-to-stand (SMD 1.01, 95% CI: 0.68 to 1.34) and 6-minute walking (SMD 0.68, 95% CI: 0.34 to 1.03). CONCLUSION: Our study provides evidence that resistance exercise velocity effects are specific in older adults, as evidenced by physical function test dependence. We suggest that prescriptions based on the velocity of contraction should be individualized to address the specific functional needs of participants.

Power Training Prescription in Older Individuals: Is It Safe and Effective to Promote Neuromuscular Functional Improvements?

Muscle power has been reported to be critical in counteracting age-related declines in functional performance. Muscle power output in functional performance exercises can be greatly improved in a short period of time (i.e., ≤ 12 weeks) using specific exercise interventions such as power training (i.e., exercises attempting to move loads ranging from 20 to 70% of 1-repetition maximum as fast as possible during the concentric muscle action, followed by a controlled, slower eccentric muscle action). Despite the widespread evidence on the effectiveness of power training in older adults (~ 300 scientific articles published on this topic in the past 10 years), some scientists do not recommend the use of explosive-type muscular contractions during resistance training (i.e., power training) for the older population; indeed, some international guidelines do not mention this type of exercise for older people. The reasons underlying this absence of mention and recommendation for the use of power training as a fundamental exercise strategy for older people are still not well known. Therefore, we attempted to point out the main issues about safety, feasibility, and effectiveness of muscle power training to promote neuromuscular functional improvements in older people.

Moderators of Resistance Training Effects in Overweight and Obese Adults: A Systematic Review and Meta-analysis.

PURPOSE: This study aimed to analyze whether the effects of resistance exercise on whole-body fat and lean mass are moderated by exercise dosage (i.e., duration, volume, and intensity), age, body mass index, baseline values, assessment methods, and prescription of aerobic exercise and caloric restriction in overweight/obese adults. METHODS: A systematic search was undertaken in 11 databases from inception to December 2020, with an updated search undertaken in April 2022. Eligible randomized controlled trials examined the effects of resistance-based exercise programs on whole-body fat mass and lean mass in adults who were overweight or obese. Meta-analysis was undertaken with a random-effects model. Associations between mean differences and potential moderators were tested by meta-regression models. RESULTS: Sixty-seven articles describing 65 trials ( n = 2537) were included. Resistance-based exercise programs resulted in a significant change of -1.6 kg (95% confidence interval [CI] = -1.9 to -1.3 kg, P < 0.001) in whole-body fat mass and +0.8 kg (95% CI = 0.6 to 0.9 kg, P < 0.001) in lean mass. Male participants experienced greater effects than females ( P < 0.001), whereas those presenting with higher levels of fat mass at baseline experienced greater reductions in this outcome ( P = 0.084). For lean mass, younger adults experienced greater improvements compared with older participants ( P = 0.009), whereas programs comprising resistance exercise and caloric restriction resulted in significant reductions in lean mass ( P = 0.035). Resistance exercise dosage or prescription of aerobic exercise was not associated with change in these outcomes. CONCLUSIONS: Resistance-based programs improve body composition regardless of the resistance exercise dosage or aerobic component prescribed in adults who are overweight or obese. In addition, subgroups based on demographic characteristics, baseline levels, and presence of caloric restriction may present with more favorable responses in body composition.

Analysis of Recovery Methods' Efficacy Applied up to 72 Hours Postmatch in Professional Football: A Systematic Review With Graded Recommendations.

BACKGROUND: Sleep, nutrition, active recovery, cold-water immersion, and massage were recently reported as the most used postmatch recovery methods in professional football. However, the recommendations concerning the effect of these methods remain unclear. PURPOSE: To systematically review the literature regarding the effectiveness of the most common recovery methods applied to male and female football players (or other team sports) 72 hours postmatches and to provide graded recommendations for their use. METHODS: A systematic search of the literature was performed, and the level of evidence of randomized and nonrandomized studies was classified as 1 or 2, respectively, with additional ++, +, and - classification according to the quality of the study and risk of bias. Graded recommendations were provided regarding the effectiveness of recovery methods for physical, physiological, and perceptive variables. RESULTS: From the 3472 articles identified, 39 met the inclusion criteria for analysis. The studies' levels of evidence varied among methods (sleep: 2+ to 1++; nutrition: 2- to 1+; cold-water immersion: 2- to 1++; active recovery: 2- to 1+; and massage: 1- to 1+). Different graded recommendations were attributed, and none of them favored the effective use of recovery methods for physiological and physical parameters, whereas massage and cold-water immersion were recommended as beneficial for perceptive variables. CONCLUSIONS: Cold-water immersion and massage can be recommended to recover up to 72 hours postmatch at a perceptive level. However, there is a current need for high-quality research that identifies effective recovery strategies that enhance recovery at the physical and physiological levels.

Which stretching instruction should be given to assess joint maximal range of motion?

This study aimed to determine the intra-day reliability, individuals performance expectancy, and biomechanical response of nine stretching instructions in assessing the maximal range of motion (mROM) during the passive ankle dorsiflexion test. Twenty healthy young participants were tested in two sessions within the same day. Nine stretching instructions composed by intensity-domain (i.e. minimum, point, and maximum) and sensation-domain (i.e. tolerance, discomfort, and pain) words were used to impose plantar flexors stretching. In the first session, individuals were requested to order the nine stretching instructions in ascending order. The ankle joint torque-angle and medial gastrocnemius, soleus and tibialis anterior electric activity were assessed in both sessions. A moderate to high reliability was observed across instructions (ICC = 0.65-0.87). Most stretching instructions showed high intra-day reliability outcomes, where discomfort and tolerance showed moderate reliability. 70% of individuals performed the stretching maneuvers consistently to stretching instructions performance expectancy. A greater torque-angle response was observed for the instructions involving the word pain (ROM = 40.5 ± 1.6°), compared to discomfort (29.5 ± 1.8°), and tolerance (30.5 ± 2.0°) that produced similar stretching intensities. Instructions involving the terms minimum (29.6 ± 2.0°), point (33.3 ± 7.6°), and maximum (37.6 ± 7.2°) were more discriminative of stretching intensities than sensation-domain terms. In conclusion, stretching instructions targeting the joint maximal range of motion produce different joint torque-angle responses and they may not be understandable by all individuals, although (in general) they can be used reliably.

Can supplemental protein to low-protein containing meals superimpose on resistance-training muscle adaptations in older adults? A randomized clinical trial.

PURPOSE: To evaluate the effects of supplementing protein to the low-protein containing meals on selected parameters of muscle mass, strength, and functional capacity in older individuals undergoing resistance training. METHODS: Thirty-one male and female older individuals (60 to 80 years) were randomized into either a whey protein/WP (n = 15, 20 g at breakfast + 20 g at dinner) or placebo-maltodextrin/PL (n = 16, 20 g at breakfast + 20 g at dinner) group. Both groups underwent a supervised, progressive resistance training (2×/week) program for 12 weeks. Maximal isometric voluntary contraction (MIVC) of knee extensors, muscle thickness (MT) of knee extensors and elbow flexors, rectus femoris muscle quality (MQ), body composition (as measured by DXA) and functional capacity [as measured by 30-s sit-to-stand (30ss) and timed-up-and-go tests (TUG)] were evaluated at baseline and after the 12-week intervention. RESULTS: Knee extensor MIVC (WP ∆ = 11.9 ± 11.4% and PL ∆ = 12.9 ± 9.9%) was significantly increased over time, with no between-group differences (all p < 0.05 for main effect of time). Upper- and lower-limb MT were significantly increased over time, with no effect of supplementation (WP: ∆ = 7.0 ± 7.3%, PL: ∆ = 9.5 ± 10.3%; and WP: ∆ = 4.5 ± 5.8%, PL: ∆ = 14.7 ± 28.9%, respectively; all p = 0.001 for main effect of time, respectively). Total and upper-limb lean mass were significantly increased, irrespective of the dietary intervention (WP: ∆ = 0.2 ± 6.3%, PL: ∆ = 1.8 ± 2.9%; and WP: ∆ = 0.10 ± 0.03%, PL: ∆ = 0.15 ± 0.02%, respectively; all p < 0.05 for main effect of time). Main effects of time (all p < 0.05) were also found for 30SS and TUG (fast and usual speeds) (WP: ∆ = 18.2 ± 34.4%, PL: ∆ = 10.4 ± 16.9%; WP: ∆ = 5.4 ± 6.7%, PL: ∆ = 0.7 ± 6.0% and WP: ∆ = 3.3 ± 6.1%, PL: ∆ = 2.3 ± 5.2%, respectively). CONCLUSION: Supplementing additional whey protein to the lowest-protein containing meals (i.e., ~20 g at breakfast and ~20 g at dinner, daily) did not further augment resistance training-induced neuromuscular adaptations (i.e. muscle strength and mass) in healthy older individuals.

Acute Blood Pressure Response to High- and Moderate-Speed Resistance Exercise in Older Adults With Hypertension.

An increase in blood pressure (BP) occurs during resistance exercise; attention to this response may be necessary in older individuals with hypertension. We compared the BP responses following high- (HSRE) and moderate-speed resistance exercise (MSRE) (4 × 8 repetitions at 60% one-repetition maximum) and control protocol in 15 older adults with hypertension. HSRE and MSRE increased systolic BP (SBP) by the end of each set compared with preexercise and control protocol. Immediately after the fourth set, a higher SBP was observed in MSRE than HSRE (147 ± 14 vs. 141 ± 12 mmHg; p = .01). Taking an exploratory analysis of the individual response, we observed that MSRE resulted in greater mean changes and number of SBP exposures to values ≥150 mmHg (22-fold) than HSRE (10-fold). Diastolic BP increased (p < .05) with exercise, but only MSRE increased compared with the control condition (p < .05). HSRE may be an alternative for individuals in which SBP peak should be avoided.

Exercise effects on muscle quality in older adults: a systematic review and meta-analysis.

To systematically review and analyse the effects of exercise on morphological and neuromuscular muscle quality (MQ) outcomes in older adults and assess a range of possible moderators that may affect the impact of exercise on MQ outcomes. Using PRISMA guidelines, randomised controlled trials were searched in CINAHL, EMBASE, LILACS, PubMed, SciELO, Web of Science, MedNar, OpenGrey and OpenThesis databases. Eligible trials examined the effects of exercise interventions on morphological and neuromuscular MQ in older adults (≥ 60 years). Twenty-one trials (n = 973 participants) were included. Exercise significantly improved morphological MQ (effect size (ES) = 0.32, 95% CI 0.13-0.51, P < 0.001) with significant results maintained for studies assessing muscle density and intermuscular adipose tissue (ES = 0.45-0.52, P < 0.05). For neuromuscular MQ, exercise provided significant positive effects (ES = 0.49, 95% CI 0.29-0.69, P < 0.001) but only maintained for physically healthy participants (ES = 0.43, P < 0.001), resistance exercise interventions (ES = 0.64, P < 0.001), or studies assessing 1-RM or knee extensor isokinetic muscle strength relative to leg lean mass (ES = 0.48-0.62, P = 0.001). Associations between exercise duration and changes in MQ measures were not observed (P > 0.05). Supervised exercise interventions significantly improved different measures of MQ regardless of exercise duration, although these effects were small-to-moderate and not supported across all population-, exercise-, and methods-related features.

Chair sit-to-stand performance is associated with diagnostic features of sarcopenia in older men and women.

BACKGROUND: Standing from a chair is a fundamental activity of daily living, and it can be applied to assess the physical function, especially in older individuals. AIM: The aim of this study was to elucidate the characteristics of mechanical and temporal parameters during chair stand based on the relationship with skeletal muscle and physical functional parameters in older men and women. METHODS: Eighty older men and women participated in this study. We measured four parameters of chair stand performance: ground reaction force (GRF), rate of force development (RFD), and chair rise time (CRT) were calculated from the foot-floor force data; sit-to-stand (STS) was also assessed by measuring the time needed to complete 10 chair stand repetitions. The muscle thickness (MT) and echo intensity, as indexes of muscle size and quality, respectively, were measured using axial B-mode ultrasound images from quadriceps femoris. The gait speed and handgrip strength were measured as physical functional parameters. RESULTS: Partial correlation was used to determine the association of chair stand performance with MT, echo intensity, and physical parameters while considering the height, body mass, and age. GRF, RFD, and STS were significantly correlated with MT (r = 0.35, 0.26, and -0.49), gait speed (r = 0.32, 0.31, and -0.67), and handgrip strength (r = 0.57, 0.59, and -0.49). As the result of regression analysis, MT, gait speed, and handgrip strength were estimated by GRF and STS. CONCLUSION: These results suggest that chair stand performance is useful as it reflects the muscle size and physical functions in older individuals.

Resistance Training Load Effects on Muscle Hypertrophy and Strength Gain: Systematic Review and Network Meta-analysis.

PURPOSE: This study aimed to analyze the effect of resistance training (RT) performed until volitional failure with low, moderate, and high loads on muscle hypertrophy and muscle strength in healthy adults and to assess the possible participant-, design-, and training-related covariates that may affect the adaptations. METHODS: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, MEDLINE, CINAHL, EMBASE, SPORTDiscus, and Web of Science databases were searched. Including only studies that performed sets to volitional failure, the effects of low- (>15 repetitions maximum (RM)), moderate- (9-15 RM), and high-load (≤8 RM) RTs were examined in healthy adults. Network meta-analysis was undertaken to calculate the standardized mean difference (SMD) between RT loads in overall and subgroup analyses involving studies deemed of high quality. Associations between participant-, design-, and training-related covariates with SMD were assessed by univariate and multivariate network meta-regression analyses. RESULTS: Twenty-eight studies involving 747 healthy adults were included. Although no differences in muscle hypertrophy between RT loads were found in overall (P = 0.113-0.469) or subgroup analysis (P = 0.871-0.995), greater effects were observed in untrained participants (P = 0.033) and participants with some training background who undertook more RT sessions (P = 0.031-0.045). Muscle strength improvement was superior for both high-load and moderate-load compared with low-load RT in overall and subgroup analysis (SMD, 0.60-0.63 and 0.34-0.35, respectively; P < 0.001-0.003), with a nonsignificant but superior effect for high compared with moderate load (SMD, 0.26-0.28, P = 0.068). CONCLUSIONS: Although muscle hypertrophy improvements seem to be load independent, increases in muscle strength are superior in high-load RT programs. Untrained participants exhibit greater muscle hypertrophy, whereas undertaking more RT sessions provides superior gains in those with previous training experience.

Comparison of muscle quality and functional capacity between Japanese and Brazilian older individuals.

Muscle quality is well-known to decrease with aging and is a risk factor for metabolic abnormalities. However, there is a lack of information on race-associated differences in muscle quality and other neuromuscular features related to functional performance. This study aimed to compare muscle quality, function, and morphological characteristics in Japanese and Brazilian older individuals. Eighty-four participants aged 65-87 years were enrolled in the study (42 Japanese: 23 men, 19 women, mean age 70.4 years; 42 Brazilians: 23 men, 19 women, mean age 70.8 years). Echo intensity (EI) and muscle thickness (MT) of the quadriceps femoris were measured using B-mode ultrasonography. A stepwise multiple linear regression analysis with EI as a dependent variable revealed that MT was a significant variable for Japanese participants (R2 = 0.424, P = 0.001), while MT and subcutaneous adipose tissue (SCAT) thickness were significant variables for Brazilian participants (R2 = 0.490, P = 0.001). A second stepwise multiple linear regression analysis was performed after excluding MT and SCAT thickness from the independent variables. Sex and age for Japanese participants (R2 = 0.381, P = 0.001) and lean body mass and body mass index for Brazilian participants (R2 = 0.385, P = 0.001) were identified as significant independent variables. The present results suggest that MT is closely correlated with muscle quality in Japanese and Brazilian older individuals. Increases in muscle size may induce decreases in intramuscular adipose tissue and/or connective tissues, which are beneficial for reducing the risks of metabolic impairments in Japanese and Brazilian older individuals.

COVID-19 pandemic is an urgent time for older people to practice resistance exercise at home.

Social distancing measures have been used to contain the COVID-19 pandemic; nevertheless, it causes unintended greater time at home and consequently a reduction in general physical activity and an increase in sedentary time, which is harmful to older people. A decrease in daily physical activities and an increase in sedentary time culminates in an impactful skeletal muscle disuse period and reduction in neuromuscular abilities related to functional capacity. Home-based resistance training is a strategy to mitigate physical inactivity and improve or retain muscle function and functional performance. Therefore, it is an urgent time to encourage older people to perform resistance exercises at home to avoid a harmful functional decline and promote physical health.

Effects of long-term concurrent training to failure or not in muscle power output, muscle quality and cardiometabolic risk factors in older men: A secondary analysis of a randomized clinical trial.

This study investigated the effects of concurrent training performed either with repetitions to failure or not to failure in muscle power, muscle quality (MQ), peak oxygen uptake (VO2peak), and visceral fat in older men. This is an ancillary analysis of a randomized controlled trial. 36 older men (mean age ± SD; 67.1 ± 5.1 years) were randomized into three groups: one performing repetitions to failure (RFG, n = 13), another performing repetitions not to failure and 50% of the repetitions of the RFG (NFG, n = 12), and third performing repetitions not to failure with equal training volume of the RFG (ENFG, n = 11). The training was performed twice a week for 20 weeks at intensities ranging from 65 to 80% of maximal strength. In each session, the individuals started with strengthening exercises and then performed aerobic exercise (i.e., walking) on a treadmill. The primary endpoint was change from baseline to post-20 wk of absolute and relative muscle power output during squat and countermovement jump, ultrasound measurements for MQ using quadriceps echo intensity, and visceral fat thickness, as well as their VO2peak through a maximal incremental test on a treadmill. All training groups improved similarly and significantly jump height (ranging from 9 to 16%) and all their muscle power outcomes (mean change ranging from 2 to 7%) (P < .001). In addition, all groups significantly decreased visceral fat thickness (ranging from -11 to -21%) (P < .001), and significantly increased VO2peak (ranging from 4 to 8%) (P < .01), with no differences between groups. No changes were observed in the MQ outcomes. Concurrent training performed using repetitions to failure or not to failure promoted similar gains in the muscle power output, aerobic capacity, and visceral fat in healthy older men.

Adaptations in mechanical muscle function, muscle morphology, and aerobic power to high-intensity endurance training combined with either traditional or power strength training in older adults: a randomized clinical trial.

PURPOSE: There is a lack of information on the effects of power training (PT) as an alternative to traditional strength training (TST) during concurrent training (CT) in older individuals. This study aimed to verify the neuromuscular adaptations that occurred following 16-week interventions with two CT models in older men: high-intensity interval training (HIIT) combined with either TST or PT. METHODS: Thirty-five older men (65.8 ± 3.9 years) were randomly assigned into one of two training groups CTS: TST + HIIT (n = 18) or CTP: PT + HIIT (n = 17). CTS performed resistance training at intensities ranging from 65 to 80% of 1 RM at slow controlled speed, whereas CTP trained at intensities ranging from 40 to 60% of 1 RM at maximal intentional speed. Lower body one-repetition maximum (1 RM), isometric rate of force development (RFD), countermovement jump (CMJ) muscle power output, quadriceps femoris muscles thickness (QF MT), and peak oxygen uptake (VO2peak) were assessed before training and after 8 and 16 weeks of CT. RESULTS: Groups improved similarly in all primary outcomes (P < 0.05), with mean increases ranging: 1 RM (from 39.4 to 75.8%); RFD (from 9.9 to 64.8%); and CMJ muscle power (from 1.8 to 5.2%). Significant increases (P < 0.05) were observed in all secondary outcomes (QF MT, specific tension and VO2peak) with no differences between groups. CONCLUSION: CT models were effective for improving maximal and explosive force (1 RM, RFD, and CMJ power), QF MT, and VO2peak. Moreover, despite that using lower loading intensities, PT induced similar adaptations to those of TST.

Muscle quality and functionality in older women improve similarly with muscle power training using one or three sets.

The present study compared the effects of 12 weeks of muscle power training performing one or three sets on muscle quality assessed by echo intensity (MQEI) and index (MQindex), muscle power-related outcomes, and functional capacity in older women. Participants were randomly assigned into two groups: 1SET (n = 13) and 3SET (n = 13). Lower limb muscle power and vertical jump height were measured during a countermovement jump, maximal rate of torque development (MRTD), and root mean square (RMS) of electromyography signals and rate of rise (RER) of quadriceps maximal electromyography activation during unilateral knee extension at 0-50 and 0-200 ms, MQEI, MQindex (absolute muscle power/MQEI, and MRTD/MQEI) and functionally in both groups using timed-up-and-go were evaluated before and after training. There were significant and similar (p < 0.05) increases in muscle power, vertical jump height, MQEI, MQindex, and functionally (p ≤ 0.0001) in both groups. In contrast, MRTD increased only in 1SET (p ≤ 0.001), and the RMS0-200 and RER0-50 increased for 3SET only (p ≤ 0.05), with no difference between groups (p > 0.05). In conclusion, similar neuromuscular adaptations and improvements in the functional performance occurred in both groups.

Effect of corporal suspension and pendulum exercises on neuromuscular properties and functionality in patients with medullar thoracic injury.

BACKGROUND: Traumatic spinal cord injury (TSCI) is one of the most devastating injuries that has a physical impact on patients. The CHORDATA® method involves suspension and pendulous exercises and has been clinically used to treat patients with TSCI. Although empirically used to treat neurological patients, there is no scientific evidence of the efficacy of this method. PURPOSE: To evaluate the chronic effects of CHORDATA® method on torque, muscle activation, muscle thickness, and functionality in patients with traumatic spinal cord injury. METHODS: Twenty-six male patients with medullar thoracic injury were randomly categorised into two groups: intervention group (n = 14) and control group (n = 12). Rehabilitation program comprised of 16 sessions of body suspension and pendulum exercises (twice/week). The maximal voluntary isometric trunk flexion and extension torques, muscle activation and thickness (external and internal oblique, rectus and transversus abdominis, longissimus, and multifidus muscles), and functionality (adapted reach test) were evaluated before and after of rehabilitation program. FINDINGS: A significant increase was observed in maximal voluntary isometric torque (flexion, 58%; extension, 76%), muscle activation of the rectus abdominis muscle, and muscle thickness of all intervention group muscles, without changes in the control group. Compared to the pre-intervention period, the intervention group also showed improvement in functionality at post-intervention, but no such differences were noted in the control group. INTERPRETATION: The corporal suspension and pendulum exercises training improved rectus abdominis muscle activation, trunk muscles structure and strength, and reaching capacity in medullar thoracic injury patients.