Effects of eccentric-focused and conventional resistance training on strength and functional capacity of older adults

Defining Clinically Meaningful Cut Points for Leg Power Impairment Using Physical Performance in Older Adults: A Secondary Analysis From Boston RISE

OBJECTIVE

To identify clinically meaningful thresholds of leg power impairment identified by the stair climb power test (SCPT).

DESIGN

Cross-sectional analysis using the baseline data from an observational cohort study.

SETTING

The Boston Rehabilitative Impairment Study of the Elderly.

PARTICIPANTS

Community-dwelling older adults (N=413).

MAIN OUTCOME MEASURES

SCPT and the Short Physical Performance Battery (SPPB).

RESULTS

Using the receiver operating characteristic curves and Youden's J statistics, the optimal threshold for the SCPT associated with mobility limitation as defined by an SPPB score ≤9 was 3.07 Watts/kg for men with a sensitivity of 74%, a specificity of 73% and, an area under the curve (AUC) value of 0.78. For women, the optimal threshold was 2.59 Watts/kg with a sensitivity of 83%, a specificity of 69%, and an AUC value of 0.81. The classification and regression tree sensitivity analysis demonstrated similar thresholds, 2.88 Watts/kg and 2.53 Watts/kg for men and women, respectively.

CONCLUSIONS

The study identified clinically meaningful thresholds of impairment for the SCPT for mobility limited older primary care patients. These thresholds may be used to inform rehabilitation care to improve functional mobility of older adults and should be validated in larger more representative clinical trials.

Benefits of Eccentric Training with Emphasis on Demands of Daily Living Activities and Feasibility in Older Adults: A Literature Review

Aging is associated with a decline in physical capabilities and several other health-related conditions. One of the most common age-related processes is sarcopenia. Sarcopenia is usually accompanied with a decline in skeletal muscle mass and physical functioning. A decrease in these markers usually impacts basic daily living activities (DLAs), which become somewhat harder to accomplish for older individuals. Several research studies have examined the demands of DLA in older individuals with results indicating that activities such as walking, sitting, standing, stair climbing, stair descending, and running generate high demands on older adults. The forces that act on individuals are in most cases equal or multiple times higher relative to their body mass. For instance, it was reported that the GRF (ground reaction force) during stair descent ranged from 1.43 to 1.50 of BW (body weight) in an older population. Even higher demands were recorded during other related activities. These demands of DLA raise the question of appropriate rehabilitative or training management procedures. During the past decades, an eccentric form of resistance training gained popularity due to its effectiveness and lower metabolic demands, which seems to be an appropriate method to develop and maintain a basic level of strength capabilities in higher age. Multiple factors of eccentric training have been examined including modality of exercise, intensity, frequency, and safety of the elderly. Several modalities of eccentric exercise have been shown to be effective including traditional methods, as well as machine-based ones, with or without using some equipment. The studies included in this review varied in intensity from low to high; however, the most frequently used intensity was ≥50% of the maximal eccentric strength during two or three eccentric sessions per week. Importantly, the prevalence of injury of older adults appears to have been low to none, highlighting the safety of this approach. In summary, eccentric training prescriptions for older adults should consider the demands of DLA and the characteristics of the elderly for appropriate management of training recommendations.

Eccentric Exercise Causes Specific Adjustment in Pyruvate Oxidation by Mitochondria

INTRODUCTION

The impact of eccentric exercise on mitochondrial function has only been poorly investigated and remains unclear. This study aimed to identify the changes in skeletal muscle mitochondrial respiration, specifically triggered by a single bout of eccentric treadmill exercise.

METHODS

Male adult mice were randomly divided into eccentric (ECC; downhill running), concentric (CON; uphill running), and unexercised control groups ( n = 5/group). Running groups performed 18 bouts of 5 min at 20 cm·s -1 on an inclined treadmill (±15° to 20°). Mice were sacrificed 48 h after exercise for blood and quadriceps muscles collection. Deep proximal (red) and superficial distal (white) muscle portions were used for high-resolution respirometric measurements.

RESULTS

Plasma creatine kinase activity was significantly higher in the ECC compared with CON group, reflecting exercise-induced muscle damage ( P < 0.01). The ECC exercise induced a significant decrease in oxidative phosphorylation capacity in both quadriceps femoris parts ( P = 0.032 in proximal portion, P = 0.010 in distal portion) in comparison with the CON group. This observation was only made for the nicotinamide adenine dinucleotide (NADH) pathway using pyruvate + malate as substrates. When expressed as a flux control ratio, indicating a change related to mitochondrial quality rather than quantity, this change seemed more prominent in distal compared with proximal portion of quadriceps muscle. No significant difference between groups was found for the NADH pathway with glutamate or glutamate + malate as substrates, for the succinate pathway or for fatty acid oxidation.

CONCLUSIONS

Our data suggest that ECC exercise specifically affects pyruvate mitochondrial transport and/or oxidation 48 h after exercise, and this alteration mainly concerns the distal white muscle portion. This study provides new perspectives to improve our understanding of the mitochondrial adaptation associated with ECC exercise.

Flywheel Training in Older Adults—A Systematic Review

The process of healthy aging might be reconsidered, based on the nonfatal outcomes of falls in older adults. Flywheel training is a relatively new training method used by different age groups, which enables the muscles to contract at maximum force in minimum time. The study aim was to summarize the relevant literature about the effects of flywheel training in older adults and to determine its efficiency and feasibility. PRISMA guidelines were followed for both the search and analysis. Electronic databases (Google Scholar, PubMed, Science Direct, Scopus, Web of Science and SPORTDiscuss) yielded 9915 studies, but we have included studies published in English between 2005 and 2021, cross-sectional and pre-post treatments, with older adults (≥60 years) as the sample, where flywheel training was conducted. A total of nine studies have met the pre-defined criteria and entered the systematic review, with a total of 216 participants, both male and female. After analyzing the obtained results, it can be concluded that flywheel training showed physical, neuromuscular, and functional improvements in older adults. However, the review did not reveal an optimal duration, frequency, intensity, or volume. Furthermore, it can be stated that this training method can be considered as an appropriate form of activity in older adults, as a tool for improving overall health.

Applications of Eccentric Exercise to Improve Muscle and Mobility Function in Older Adults

Muscle aging ultimately leads to the deterioration of human physiological functioning, including declining muscle strength, loss of muscle mass, and decreased quality of life in advanced age. Eccentric exercise is a key intervention that has the potential to ameliorate this problem. Recent studies have focused on evidence-based exercise interventions to prevent declines in muscle strength and physical function in older adults. This paper reviewed relevant literature on the use of eccentric exercise to improve muscle and mobility function in older adults. We explained not only the changes in mobility that occur with aging but also the rationale for and positive effects of eccentric intervention in older adults. We also explored several proposed mechanisms for the intramuscular changes caused by eccentric muscle contraction and considered the safety and side effects accompanying eccentric training. We concluded by suggesting that eccentric exercise is an exercise modality that can potentially improve muscle strength and enhance mobility in older adults.

Improved Muscle Strength, Muscle Power, and Physical Function After Flywheel Resistance Training in Healthy Older Adults: A Randomized Controlled Trial

ABSTRACT

Sañudo, B, de Hoyo, M, and McVeigh, JG. Improved muscle strength, muscle power, and physical function after flywheel resistance training in healthy older adults: A randomized controlled trial. J Strength Cond Res 36(1): 252-258, 2022-This study aimed to examine whether flywheel resistance exercise training improved muscle strength, muscle power, and physical function in older adults. Thirty-six older adults (64 ± 5 years) were randomly allocated to either a flywheel resistance exercise training group (ETG; n = 18) or a control (CON) group (n = 18). Subjects in the ETG underwent 6 weeks of resistance training on a flywheel squat device (4 sets of 9 maximal repetitions). Isokinetic concentric (60 and 240°·s-1) and eccentric (120°·s-1) knee extension and flexion peak torques and mean power were measured. Physical function was assessed by the 30-second Chair Sit-Stand Test (CST) and walking speed. After the intervention, within-group analyses showed significantly greater flexion torques and mean power with the dominant leg (concentric at 60°·s-1 and 240°·s-1 and eccentric at 120°·s-1; all d > 0.7, p < 0.05) and improvements in CST (d > 0.8) in the ETG, while no substantial differences were found in the CON group. Significant between-group differences in knee flexion torque both concentric (at 60°·s-1: η2 = 0.168 and 240°·s-1: η2 = 0.112) and eccentric (at 120°·s-1: η2 = 0.103) with the dominant leg were also found in favor of the ETG. There was also significantly better performance in the CST for the ETG (η2 = 0.207). There was a significant association between changes in strength and changes in mean power in the ETG. Changes in physical function outcomes were also observed. In conclusion, flywheel resistance exercise training is an appropriate form of activity for improving strength and functional capacity of older adults.

Effects of resistance training on hypertrophy, strength and tensiomyography parameters of elbow flexors: role of eccentric phase duration

The aim of the study was to compare the effects of two different training protocols, which differ in the duration of the eccentric phase, on the one-repetition maximum (1RM), thickness and contractile properties of elbow flexors. Twenty untrained college students were randomly divided into two experimental groups, based on the training tempo: FEG (Faster Eccentric Group: 1/0/1/0) and SEG (Slower Eccentric Group: 4/0/1/0). Training intervention was a biceps bending exercise, conducted twice a week for 7 weeks. The intensity (60–70% RM), sets (3–4) and rest intervals (120 s) were held constant, while repetitions were performed until it was not possible to maintain a set duration. In the initial and final measurements, 1RM, muscle thickness and tensiomyography parameters – contraction time (Tc) and radial deformation (Dm) – were evaluated. An ANCOVA model (using baseline outcomes as covariates) was applied to determine between-group differences at post-test, while Pearson’s product-moment correlation coefficient was used to investigate the relationship between absolute changes in muscle thickness and Dm. Muscle strength increase was greater for SEG than for FEG (6.0 ± 1.76 vs. 3.30 ± 2.26 kg, p < 0.01). In both groups muscle thickness increased equally (FEG: 3.24 ± 2.01 vs. SEG: 3.57 ± 1.17 mm, p < 0.01), while an overall reduction in Dm was observed (FEG: 1.99 ± 1.20 vs. SEG: 2.26 ± 1.03 mm, p < 0.01). Values of Tc remained unchanged. A significant negative relationship was observed between changes in muscle thickness and Dm (r = -0.763, Adj.R² = 0.560, p < 0.01). These results indicate that the duration of the eccentric phase has no effect on muscle hypertrophy in untrained subjects, but that slower eccentric movement significantly increases 1RM.

Eccentric-only versus concentric-only resistance training effects on biochemical and physiological parameters in patients with type 2 diabetes

Background

The benefits of resistance training for patients with type 2 diabetes (T2D) are well documented; however, the effects of exercise with different muscle contraction types such as eccentric versus concentric contractions on physiological outcomes for this population are not clear. This study compared eccentric-only (ECC) and concentric-only resistance training (CON) to test the hypothesis that ECC would be superior to CON to improve insulin sensitivity, lipid profile, body composition, muscle strength and physical function of patients with T2D.

Methods

Adults with T2D (50–79 years) were allocated to the ECC (n = 9) or CON group (n = 9). Resistance exercises (chest press, lateral pulldown, bicep curl, triceps extension, leg extension, leg curl, calf raise, abdominal crunch) consisting of 2–3 sets of 10 eccentric-only (5 s) or concentric-only contractions (1–2 s) was performed twice a week for 12 weeks. Changes in blood biomarkers, body composition, muscle strength and physical function from pre- to post-intervention were compared between groups.

Results

Overall rating of perceived exertion (RPE, 1–10 Borg scale) was lower (p < 0.05) for ECC (2.9 ± 1.2) than CON (5.4 ± 1.1). No significant changes in blood biomarkers were found for both groups. Lean mass increased [effect size (ES) = 0.148, ECC 3.2 ± 6.9%; CON 3.6 ± 2.3%], and fat mass decreased (ES = 0.545, ECC − 6.1 ± 12.4%; CON − 7.1 ± 16.4%) (p < 0.05) similarly. One-repetition maximal strength of each exercise increased (p < 0.05) for both ECC (12–37%) and CON (27–68%). Both groups improved (p < 0.05) 6-min walk distance (ES = 0.083, ECC 12.2 ± 2.3%; CON 12.5 ± 15.3%) and chair rise time (ES = 0.463, ECC − 13.4 ± 25.4%; CON − 20.0 ± 53.3%) but only ECC improved (p < 0.05) the timed up-and-go test (− 11.3 ± 13.6%, ES 0.014). No significant changes in balance tests were found for both groups.

Conclusion

These results did not fully support the hypothesis but showed that ECC was as effective as CON to improve body composition, muscle strength, and physical function with lesser RPE. Future studies should investigate whether larger differences between ECC and CON are evident when increasing the exercise frequency and matching the intensities of the two-exercise protocols.

Trial registration ACTRN12621001026819 (retrospectively registered on 5th Aug 2021).

Effectiveness of eccentric-biased exercise interventions in reducing the incidence of falls and improving functional performance in older adults: a systematic review

Aim

To systematically review the literature on the effectiveness of eccentric exercise interventions in reducing falls and improving the functional performance in older adults.

Findings

The existing literature was of mixed quality and suggested that eccentric exercises can be as effective as conventional exercises in improving functional performance in healthy older adults. There was limited evidence focussing on the aspect of incidence of falls.

Message

Eccentric exercises may be as effective as conventional exercises in improving geriatric function, although evidence remains limited. More research is needed to explore any adverse effects of such exercises in older adults.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41999-021-00571-8.

Background

Exercise has been known to preserve and enhance functional performance in older adults. Eccentric exercise involves muscle contractions characterised by unique features such as lengthening of the muscle–tendon complex by a greater opposing force.

Aims

To systematically review randomised-controlled trials (RCTs) investigating the effectiveness of eccentric exercises in reducing the incidence of falls and improving the functional performance in older adults.

Key methods

We conducted a systematic review of RCTs following the PRISMA-P guidelines. Searches were completed in the Cochrane Central Register of Controlled Trials, Embase, CINAHL, Medline, and Global Health CABI. We included RCTs reporting at least one of the following outcomes—falls, Berg balance scale, timed-up and go test, chair stand test, stair climb test, maximal walking speed, and minute walking distance. Two reviewers screened papers for eligibility and assessed the quality of included papers using the Cochrane Collaborative risk-of-bias tool for randomised trials. Data were extracted by a single reviewer and cross-checked by the second reviewer. A narrative synthesis was undertaken, given the high level of heterogeneity across studies.

Results

Ten studies were assessed as eligible for inclusion in the review. Overall, eccentric exercises were as effective as conventional resistance exercises in improving the selected outcomes by most studies. Additionally, when pre-exercise and post-eccentric exercise functional performance measures were compared, there was a statistically significant improvement in nearly all measures. The quality of trials was mixed (one high, four moderate, two low–moderate, and three low risk of bias).

Conclusions

Our systematic review suggests that eccentric exercises can be as effective as conventional exercises in older adults. Evidence suggests that such exercise interventions can lead to an improvement in geriatric function.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41999-021-00571-8.

Effects of Training with Different Modes of Strength Intervention on Psychosocial Disorders in Adolescents: A Systematic Review and Meta-Analysis

Physical exercise has a positive impact on anxiety and depression. However, the evidence that associates strength training with a decrease in adolescents' psychosocial disorders is scarce. Consequently, the objective was to analyze the effects of training with different modes of strength intervention on anxiety, stress, and depression in adolescents. The search was designed according to PRISMA^®. We searched WoS, Scopus, SPORTDiscus, PubMed, and MEDLINE (2010-2020). Methodological quality and risk of bias were assessed with the Cochrane Collaboration. The analysis was carried out with a standardized mean difference (SMD) pooled using the Hedges g test (95% CI). The Main Outcome Measures were: anxiety, stress, and depression in adolescents post strength training. Nine studies were included in the systematic review and seven in the meta-analysis. These studies showed a large and significant effect of strength training on anxiety (SMD = -1.75; CI = 95%: -3.03, -0.48; p = 0.007) and depression (SMD = -1.61; CI = 95%: -2.54, -0.67, p = 0.0007). In conclusion, training with different modes of strength intervention have shown control over anxiety and depression in adolescents. However, conventional strength training seems to have better results than other modes of strength intervention.

Rating of Perceived Exertion as a Method to Determine Training Loads in Strength Training in Elderly Women: A Randomized Controlled Study

Objective: The aim of this study was to compare the effects of training using loads from a repetition maximum value (%1RM) and rating of perceived exertion (RPE) in elderly women. Methods: Twenty-five elderly women (60–75 years old) were randomly assigned to a group that trained using loads determined by 1RM test (G%; n = 12) or to a group that trained using loads determined by RPE (GPE; n = 13). Elderly women trained for 12 weeks using five exercises performed with 2–3 sets of 8–15 repetitions. Loads progressed from 45% to 75% of 1RM (G%) and from 13 to 18 from Rating Perceived Exertion of Borg Scale (GPE). The outcome measures, 1RM and maximum repetitions (RMs with 70% 1RM), were assessed before, between and after training programs. Results: Increased 1RM value and RMs were observed in both groups (20–42%, p < 0.001 and 56–76%, p < 0.001, respectively, for %G; and 17–56%, p < 0.001 and 47–106%, p < 0.001, respectively, for GPE), without differences between them. Conclusions: Prescribing loads using the RPE and 1RM might be similarly effective for training elderly women in order to promote strength gains. As a practical application, RPE could be an additional method to determine training loads. In spite of the promising results of the present study, it is not possible to state that the use of RPE is effective in monitoring loads during sub maximal strength training in elderly and more research must be carried out to confirm it.

Down stair walking: A simple method to increase muscle mass and performance in 65+ year healthy people

Exercise is important for prevention of sarcopenia in the elderly population. We tested two training modalities, ascending or descending stair walking, representing concentric (CON) and eccentric (ECC) exercise, respectively. We also tested the effects of additional weight during eccentric exercise (ECC+). Thirty-two healthy men and women (70 ± 3 [mean ± SE] yrs.) were randomly assigned to CON, ECC, or ECC+ (carrying +15% of body weight in a vest) in a 3 (n = 32) or 6 (n = 21) week intervention (3 sessions/week). Data was analysed by mixed models approach. Rate of perceived exertion (RPE; Borg scale 6-20; mean values from 3 and 6 weeks) during training did not differ between CON (12.3 ± 0.4), ECC (11.5 ± 0.3), and ECC+ (11.7 ± 0.4). After 6 weeks, leg muscle mass increased more in ECC+ (+0.29 ± 0.09 kg) vs CON (+0.08 ± 0.05 kg) (P<0.05) but not different from ECC (+0.16 ± 0.06 kg). 6-minute walk test (6MWT) increased after 6 weeks more (P<0.05) in ECC+ (+85 ± 23 m) compared with ECC (+37 ± 13 m) and CON (+27 ± 12 m). Intramyocellular glycogen content increased from 359 ± 19 nmol/mg d.w. in CON (to 511 ± 65 and 471 ± 44 after 3 and 6 wks, respectfully (P<0.05)), but not in ECC (to 344 ± 28 after 6 weeks) or in ECC+ (to 389 ± 20 after 6 weeks). Conclusion: carrying extra weight while descending stair walking do not increase RPE, but the ECC+ training resulted in greater muscle responses compared with CON, but glycogen synthesis was stimulated only in CON. Descending stairs is a simple model for prevention and treatment of sarcopenia and the stimulus is enhanced by carrying extra weights.

Effects of Prolonging Eccentric Phase Duration in Parallel Back-Squat Training to Momentary Failure on Muscle Cross-Sectional Area, Squat One Repetition Maximum, and Performance Tests in University Soccer Players

ABSTRACT

Shibata, K, Takizawa, K, Nosaka, K, and Mizuno, M. Effects of prolonging eccentric phase duration in parallel back-squat training to momentary failure on muscle cross sectional area, squat one repetition maximum, and performance tests in university soccer players. J Strength Cond Res 35(3): 668-674, 2021-This study aimed to compare 2 squat training programs repeated until momentary failure with different eccentric phase duration (2 seconds vs. 4 seconds) on the changes in muscle cross-sectional area, squat 1 repetition maximum (1RM), squat jump (SJ), and countermovement jump (CMJ) height, agility (T-test), and Yo-Yo intermittent recovery test (YY-IR2). Male university soccer players (19.9 ± 0.9 years, 172.2 ± 3.8 cm, 66.1 ± 6.6 kg) were randomly assigned to one of the 2 groups; CON for 2 seconds and ECC for 4 seconds (C2/E4, n = 11) or CON for 2 seconds and ECC for 2 seconds (C2/E2, n = 11). They performed parallel back-squat exercises twice a week for 6 weeks using 75% 1RM weight to momentary failure in each set for 3 sets with each protocol. Outcome measurements were taken before (Pre) and after 3 (Mid; 1RM, SJ, and CMJ only), and at 6 weeks (Post). One repetition maximum increased more (p < 0.05) for C2/E2 (Pre: 95.9 ± 12.2 kg, Mid: 108.2 ± 15.4 kg, Post: 113.6 ± 14.8 kg) than C2/E4 (95.5 ± 12.9 kg, 102.7 ± 15.6 kg, 105.5 ± 14.9 kg, respectively). Cross-sectional area (50% of the thigh length: 3.5 ± 2.8%), SJ (6.7 ± 8.9%) and CMJ height (6.3 ± 8.6%) increased similarly between C2/E2 and C2/E4, but no significant changes in T-test or YY-IR2 were evident in either group. These results suggest that increasing the ECC phase duration during squat exercises does not produce greater training effects when compared with a shorter ECC phase-duration program with momentary failure.

What is the traditional method of resistance training: a systematic review

BACKGROUND

Many resistance studies state that they used the traditional method of resistance training in the intervention. However, there is a wide difference on the characteristics of the training protocols used even though they are labeled as "the traditional method". There is no clear definition and characteristics for the traditional method of resistance training.

OBJECTIVE

To describe the most common definitions and references, and also the main characteristics of the training variables of the studies using the traditional training method for strengthening.

DATABASE

Searches were carried out in Pubmed, Embase, SPORTDiscus and Web of Science.

STUDY SELECTION

We included randomized controlled trials that included a strengthening program using the "traditional method" and that evaluated hypertrophy and/or maximum strength in healthy individuals.

RESULT

The initial search resulted in 26,057 studies, but only 39 studies were eligible and included in this review. The common characteristics of the traditional training protocol were frequency of 3 sessions/week, 3 sets of 9 repetitions, with weight = 75% 1RM. The movement time was 2±1 seconds for the concentric and for the eccentric phases. Resting time between sets was 2±1 minutes. The concepts used to define the method as traditional and the characteristics of the intervention protocols were different. The American College of Sports Medicine (ACSM) was the most cited reference.

CONCLUSIONS

The "traditional method of resistance training" can be defined as: "Three (±1) sets of 9±6 repetitions of concentric and eccentric exercises using an external load of 75±20% of one maximum repetition, completed 3±1 times/week.

Characteristics of Physical Exercise Programs for Older Adults in Latin America: A Systematic Review of Randomized Controlled Trials

AIM

To characterize physical exercise programs for older adults in Latin America.

METHODS

This review was conducted in accordance with the PRISMA statement. A search for randomized controlled trials (RCTs) published between the years 2015 and 2020 was performed in the Scopus, MedLine and SciELO databases.

RESULTS

A total of 101 RCTs were included. A large percentage of the studies had an unclear risk of bias in the items: selection, performance, detection and attribution. Furthermore, a heterogeneous level of compliance was observed in the CERT items. A total sample of 5013 older adults (79% women) was included. 97% of the studies included older adults between 60-70 years, presenting an adherence to the interventions of 86%. The studies were mainly carried out in older adults with cardiometabolic diseases. Only 44% of the studies detailed information regarding the place of intervention; of these studies, 61% developed their interventions in university facilities. The interventions were mainly based on therapeutic physical exercise (89% of the articles), with a duration of 2-6 months (95% of the articles) and a frequency of 2-3 times a week (95% of the articles) with sessions of 30-60 min (94% of the articles) led by sports science professionals (51% of the articles). The components of physical fitness that were exercised the most were muscular strength (77% of the articles) and cardiorespiratory fitness (47% of the articles). Furthermore, only 48% of the studies included a warm-up stage and 34% of the studies included a cool-down stage.

CONCLUSIONS

This systematic review characterized the physical exercise programs in older adults in Latin America, as well the most frequently used outcome measures and instruments, by summarizing available evidence derived from RCTs. The results will be useful for prescribing future physical exercise programs in older adults.

The effects of whole-body electromyostimulation (WB-EMS) in comparison to a multimodal treatment concept in patients with non-specific chronic back pain-A prospective clinical intervention study

Background

According to present guidelines, active exercise is one key component in the comprehensive treatment of nonspecific chronic back pain (NSCBP). Whole body electromyostimulation (WB-EMS) is a safe, and time-effective training method, that may be effective in NSCBP-patients.

Methods

In this prospective and controlled nonrandomized clinical study, two therapeutic approaches were compared. One group received 20 minutes WB-EMS per week. An active control group (ACG) received a multimodal therapy program. A third group included subjects without back pain. To all groups, the following measurement instruments were applied: Numeric Rating Scale (NRS), Oswestry Disability Index (ODI), North American Spine Society Instrument (NASS); SF 36 survey and measurements for muscular function and postural stability. In the EMS-group: T0: baseline; T1: at 6 weeks; T2: at 12 weeks and T3: at 24 weeks. In the ACG: T0 baseline and T1 after 4 weeks.

Results

In the intervention group, 128 patients with low back pain were enrolled, 85 in the WB-EMS group and 43 in the ACG. 34 subjects were allocated to the passive control group. The average age was 58.6 years (18–86 years). In the EMS group, the NRS (1–10) improved statistically and clinically significantly by 2 points. The ODI was reduced by 19.7 points. The NASS and most of the SF 36 items improved significantly. In the multimodal treatment group, only the muscular function improved slightly.

Conclusion

Our data support the hypothesis that WB-EMS is at least as effective as a multimodal treatment, which is often referred to as being the golden standard. Therefore WB-EMS may be an effective and, with 20 min./week training time, very time-efficient alternative to established multimodal treatment models.

The acute transcriptional response to resistance exercise: impact of age and contraction mode

Optimization of resistance exercise (RE) remains a hotbed of research for muscle building and maintenance. However, the interactions between the contractile components of RE (i.e. concentric (CON) and eccentric (ECC)) and age, are poorly defined. We used transcriptomics to compare age-related molecular responses to acute CON and ECC exercise. Eight young (21±1 y) and eight older (70±1 y) exercise-naïve male volunteers had vastus lateralis biopsies collected at baseline and 5 h post unilateral CON and contralateral ECC exercise. RNA was subjected to next-generation sequencing and differentially expressed (DE) genes tested for pathway enrichment using Gene Ontology (GO). The young transcriptional response to CON and ECC was highly similar and older adults displayed moderate contraction-specific profiles, with no GO enrichment. Age-specific responses to ECC revealed 104 DE genes unique to young, and 170 DE genes in older muscle, with no GO enrichment. Following CON, 15 DE genes were young muscle-specific, whereas older muscle uniquely expressed 147 up-regulated genes enriched for cell adhesion and blood vessel development, and 28 down-regulated genes involved in mitochondrial respiration, amino acid and lipid metabolism. Thus, older age is associated with contraction-specific regulation often without clear functional relevance, perhaps reflecting a degree of stochastic age-related dysregulation.

Strength training and protein supplementation improve muscle mass, strength, and function in mobility-limited older adults: a randomized controlled trial

BACKGROUND

Adaptation to strength training in very old mobility-limited individuals is not fully characterized. Therefore, the aim of this study was to perform a thorough investigation of the adaptation to a lower body strength training regime in this population, with particular emphasis on the relationship between changes in selected variables.

METHODS

Twenty-two mobility-limited older men and women (85 ± 6 years) were randomized to either a group performing 30 min of heavy-load strength training three times a week, with daily protein supplementation, for 10 weeks (ST), or a control group. End points were leg lean mass assessed by DXA, muscle thickness assessed by ultrasound, isometric and dynamic strength, rate of torque development, and functional capacity.

RESULTS

Leg lean mass increased from baseline in ST (0.7 ± 0.3 kg), along with increased thickness of vastus lateralis (4.4 ± 3.2%), rectus femoris (6.7 ± 5.1%), and vastus intermedius (5.8 ± 5.9%). The hypertrophy was accompanied by improved knee extensor strength (20-23%) and functional performance (7-11%). In ST, neither the change in leg lean mass nor muscle thickness correlated with changes in muscle strength. However, a strong correlation was observed between the change in isometric strength and gait velocity (r = 0.70).

CONCLUSIONS

The mismatch between gains in muscle size and strength suggests that muscle quality-related adaptations contributed to the increases in strength. The correlations observed between improvements in strength and function suggests that interventions eliciting large improvements in strength may also be superior in terms of functional gains in this population.

Glutamine-stimulated in vitro hypertrophy is preserved in muscle cells from older women

Age-related loss of muscle mass may result from reduced protein synthesis stimulation in response to anabolic stimuli, such as amino acid (AA) supplementation. The exact etiology of anabolic resistance to AA remains unclear. Therefore, the aim of this study was to investigate the anabolic response [cell size, protein synthesis and mechanistic target of rapamycin (mTOR) pathway] to the AA glutamine (a strong anabolic AA highly present in skeletal muscle) in myotubes obtained from 8 young (YW; 21-35 yrs) and 8 older (OW; 65-70 yrs) healthy women. This in vitro model of human primary myogenic cells explores the intrinsic behavior of muscle cells, while excluding potential influences of external factors. We showed that despite lower muscle mass, strength and cardiorespiratory fitness in OW compared to YW, myotube size (myotube diameter and area) and protein synthesis were not altered in OW, and glutamine-induced myotube hypertrophy and protein synthesis were preserved in OW. Apart from a lower glutamine-induced increase in P70S6 kinase phosphorylation in OW, no significant differences in other components of the mTOR pathway were observed between groups. Altogether, our data support the idea that the intrinsic capacity of muscle cells to respond to glutamine stimulation is preserved in healthy older women.

Short-Term Training and Detraining Effects of Supervised vs. Unsupervised Resistance Exercise in Aging Adults

Orange, ST, Marshall, P, Madden, LA, and Vince, RV. Short-term training and detraining effects of supervised vs. unsupervised resistance exercise in aging adults. J Strength Cond Res 33(10): 2733-2742, 2019-This study compared the effects of a 4-week supervised (SUP) resistance training program and unsupervised (UNSUP) resistance training program followed by 12 weeks of detraining (DET). Thirty-six healthy aging adults (age: 53.6 ± 3.6 years; body mass index: 28.3 ± 5.1 kg·m) were randomly allocated to an SUP group (n = 17) or a UNSUP group (n = 19). Participants completed 3 training sessions per week using resistance bands and body weight movements. Measures of physical performance were administered at baseline, at the end of the training program, and after the DET period. Function was assessed with the 6-minute walk test (6MWT), timed up-and-go (TUG), 30-second chair sit-to-stand (STS), stair-climb test (SCT), 40-m fast-paced walk test (FPWT) and sit-and-reach test (SRT), whereas the isometric midthigh pull (IMTP) and hand grip test were used to measure muscle strength. After training, improvements in performance were found in the 6MWT, TUG, 30-second chair STS, SCT, FPWT, SRT, and IMTP (p ≤ 0.05), with no significant differences between groups (p > 0.05). In addition, most of the training-induced improvements remained significantly above baseline values after the DET period (p ≤ 0.05). No significant between-group differences were observed after training or DET (p > 0.05). Four weeks of either SUP or UNSUP resistance training is sufficient to substantially improve muscle strength and function in aging adults, and these gains are largely preserved after prescribed exercise cessation. Home-based resistance training seems to be a practical and effective alternative to traditional SUP programs that may help circumvent many barriers to physical activity in aging adults.

Effects of Eccentric-Focused Versus Conventional Training on Lower Limb Muscular Strength in Older People: A Systematic Review With Meta-Analysis

Eccentric-focused training promotes greater gains in muscle strength compared to other types of training in adults. However, for older people, these findings are still not well understood. A systematic review and meta-analysis were performed using manuscripts that performed eccentric-focused (ET) and conventional resistance training (CT) at least four weeks and evaluated maximum muscle strength through tests of maximum repetitions in weight machine exercises (knee extension and leg press exercises). Five studies were included (n=138). Increases in muscle strength were found in both resistance training groups, without difference between them through meta-analysis. However, a large effect size has been observed only in ET. The findings suggest that resistance training protocols are similar to improve maximal strength in older people, despite larger effect sizes for eccentric-focused training.

Isokinetic eccentric training is more effective than constant load eccentric training on the quadriceps rehabilitation following partial meniscectomy: A randomized clinical trial

OBJECTIVES

To compare the effects of conventional (constant load) eccentric training and isokinetic eccentric training on quadriceps muscle mass, strength and functionality of recreational athletes following partial meniscectomy.

DESIGN

Randomized controlled trial.

SETTING

XXXX, Brazil.

PARTICIPANTS

32 recreational male athletes (∼27 years old) who underwent partial meniscectomy performed a 6-week quadriceps strength training program in one of the experimental groups: conventional group (CG) or icokinetic group (IG).

MAIN OUTCOME MEASURES

Quadriceps muscle mass, strength, and patients' objective and self-reported function.

RESULTS

Both groups enhanced muscle mass, strength and functionality outcomes. The IG presented higher increases than CG for muscle mass (ES = 0.99-1.41), strength (ES = 1.48-2.35), and Lysholm score (ES = 1.0). The magnitude-based inference supports that results 'very likely' or 'almost certainly' favour IG compared to CG for all outcomes, except for the single leg hop test (i.e., between-group similar change).

CONCLUSION

After partial meniscectomy, isokinetic eccentric training is more effective than conventional eccentric training to restore quadriceps muscle mass, strength, and functional capacity.

Effect of whey protein supplementation combined with resistance training on body composition, muscular strength, functional capacity, and plasma-metabolism biomarkers in older women with sarcopenic obesity: A randomized, double-blind, placebo-controlled trial

BACKGROUNDS & AIMS

Obesity and sarcopenia are independent illnesses associated with contemporary dietary and physical activity behaviors, aggravated by aging. Their coexistence is termed sarcopenic obesity (SO). Hence, increasing protein intake and resistance training (RT) are interventions that could counteract these illnesses. The objective of this investigation was to analyze the effects of whey protein (WP) supplementation associated with RT on body composition, muscular strength, functional capacity, and plasma-metabolism biomarkers in older women with SO.

METHODS

Twenty six sarcopenic (appendicular lean soft tissue ALST < 15.02 kg) obese (body fat mass ≥ 35%) older women were randomly assigned to receive daily, either 35 g of WP (WP group) or placebo (PLA group), combined with supervised RT (8 exercises, 3 × 8-12 rep, 3 times a week), during a 12-week protocol. Blood samples, blood pressure, dietary intake, functional capacity tests, the one repetition maximum (1RM) test, and body composition were assessed before and after the intervention period. Two-way analysis of variance for repeated measures was applied for comparisons.

RESULTS

The WP group presented greater (P < 0.05) increases in ALST (WP = 6.0% vs. PLA = 2.5%) and decreases in (P < 0.05) total (-3.3% vs. -0.3%) and trunk fat mass (WP = -5.1% vs. PLA = -1.1) and IL-6 (WP = -34.6% vs. PLA = 9.3%) compared with the PLA group. Both groups demonstrated improved (P < 0.05) scores for muscular strength, waist-hip ratio, functional capacity, and other plasma-metabolism biomarkers without significant differences between conditions.

CONCLUSION

Whey protein combined with RT increased ALST, and decreased total and trunk fat mass, improving sarcopenia and decreasing SO in older women, with a limited impact on inflammation. Registered under ClinicalTrials.gov Identifier n° NCT03752359.

The effects of 12-week progressive strength training on strength, functional capacity, metabolic biomarkers, and serum hormone concentrations in healthy older women: morning versus evening training

Previous findings suggest that performing strength training (ST) in the evening may provide greater benefit for young individuals. However, this may not be optimal for the older population. The purpose of this study was to compare the effects of a 12-week ST program performed in the morning vs. evening on strength, functional capacity, metabolic biomarker and basal hormone concentrations in older women. Thirty-one healthy older women (66 ± 4 years, 162 ± 4 cm, 75 ± 13 kg) completed the study. Participants trained in the morning (M) (07:30, n = 10), in the evening (E) (18:00, n = 10), or acted as a non-training control group (C) (n = 11). Both intervention groups performed whole-body strength training with 3 sets of 10-12 repetitions with 2-3 minutes rest between sets. All groups were measured before and after the 12-week period with; dynamic leg press and seated-row 6-repetition maximum (6-RM) and functional capacity tests (30-second chair stands and arm curl test, Timed Up and Go), as well as whole-body skeletal muscle mass (SMM) (kg) and fat mass (FM-kg, FM%) assessed by bioelectrical impedance (BIA). Basal blood samples (in the intervention groups only) taken before and after the intervention assessed low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), blood glucose (GLU), triglycerides (TG), high-sensitive C-reactive protein (hsCRP) concentrations and total antioxidant status (TAS) after a 12 h fast. Hormone analysis included prolactin (PRL), progesterone (P) estradiol (ESTR), testosterone (T), follicle stimulating hormone (FSH), and luteinizing hormone (LH). While C showed no changes in any variable, both M and E significantly improved leg press (+ 46 ± 22% and + 21 ± 12%, respectively; p < 0.001) and seated-row (+ 48 ± 21% and + 42 ± 18%, respectively; p < 0.001) 6-RM, as well as all functional capacity outcomes (p < 0.01) due to training. M were the only group to increase muscle mass (+ 3 ± 2%, p < 0.01). Both M and E group significantly (p < 0.05) decreased GLU (-4 ± 6% and -8 ± 10%, respectively), whereas significantly greater decrease was observed in the E compared to the M group (p < 0.05). Only E group significantly decreased TG (-17 ± 25%, p < 0.01), whereas M group increased (+ 15%, p < 0.01). The difference in TG between the groups favored E compared to M group (p < 0.01). These results suggest that short-term "hypertrophic" ST alone mainly improves strength and functional capacity performance, but it influences metabolic and hormonal profile of healthy older women to a lesser extent. In this group of previously untrained older women, time-of-day did not have a major effect on outcome variables, but some evidence suggests that training in the morning may be more beneficial for muscle hypertrophy (i.e. only M significantly increased muscle mass and had larger effect size (M: g = 2 vs. E: g = 0.5).

Ultra-short-term heart rate variability during resistance exercise in the elderly

Despite the appeal of ultra-short-term heart rate variability (HRV) methods of analysis applied in the clinical and research settings, the number of studies that have investigated HRV by analyzing R-R interval (RRi) recordings shorter than 5 min is still limited. Moreover, ultra-short-term HRV analysis has not been extensively validated during exercise and, currently, no indications exist for its applicability during resistance exercise. The aim of the present study was to compare ultra-short-term HRV analysis with standard short-term HRV analysis during low-intensity, dynamic, lower limb resistance exercise in healthy elderly subjects. Heart rate (HR) and RRi signals were collected from 9 healthy elderly men during discontinuous incremental resistance exercise consisting of 4-min intervals at low intensities (10, 20, 30, and 35% of 1-repetition maximum). The original RRi signals were segmented into 1-, 2-, and 3-min sections. HRV was analyzed in the time domain (root mean square of the of differences between adjacent RRi, divided by the number of RRi, minus one [RMSSD]), RRi mean value and standard deviation [SDNN] (percentage of differences between adjacent NN intervals that are greater than 50 ms [pNN50]), and by non-linear analysis (short-term RRi standard deviation [SD1] and long-term RRi standard deviation [SD2]). No significant difference was found at any exercise intensity between the results of ultra-short-term HRV analysis and the results of standard short-term HRV analysis. Furthermore, we observed excellent (0.70 to 0.89) to near-perfect (0.90 to 1.00) concordance between linear and non-linear parameters calculated over 1- and 2-min signal sections and parameters calculated over 3-min signal sections. Ultra-short-term HRV analysis appears to be a reliable surrogate of standard short-term HRV analysis during resistance exercise in healthy elderly subjects.

Comparing the effects of two distinct eccentric modalities to traditional resistance training in resistance trained, higher functioning older adults

BACKGROUND

The effects of eccentric resistance exercise are of interest in the older adult cohort, but to our knowledge, there is no research on the relative effects of different eccentric modalities on a range of outcomes in higher functioning, resistance trained older adults.

METHODS

33 resistance-trained older adults (aged 67±4.5years) were randomized into one of three supervised training groups: traditional (TRE), eccentric only (ERE) or eccentrically biased resistance exercise (EBRE) on a 45°, plate-loaded leg press machine. Participants trained twice per week with maximal strength, functional capacity, body composition and blood biomarkers measured before and after the eight-week intervention.

RESULTS

Both eccentric and concentric strength, and important functional tasks for independent living significantly improved independent of group. Body composition and blood biomarkers were found to significantly improve in the EBRE group only however, no statistical differences were found between groups.

CONCLUSION

Compared to traditional resistance training, the two eccentric modalities investigated here were equally effective for improvements in maximum muscular strength, functional capacity, body composition and metabolic biomarkers. When training the resistance trained older adult, very heavy isoinertial external loads (at least 70% of one repetition maximum) are effective irrespective of contraction mode. With heavy strength training, resistance trained older adults can continue to expect improvements in health and function.

Balance and mobility training with or without concurrent cognitive training improves the timed up and go (TUG), TUG cognitive, and TUG manual in healthy older adults: an exploratory study

BACKGROUND AND AIMS

The purpose was to explore the impact of balance and mobility training (BMT), balance and mobility plus cognitive training (BMT + C) and no training on the timed up and go (TUG), TUG cognitive (TUGcog), and TUG manual (TUGman) in older adults. A preliminary experiment examined the stability of these TUG measures over a 5-week period in older adults.

METHODS

Fifteen participants in the BMT group (70.2 ± 3.2 years) and 14 participants in the BMT + C group (68.7 ± 5.5 years) trained one-on-one, 3×/week for 12 weeks on a balance obstacle course. The BMT group and the BMT + C group completed two or three tasks simultaneously, respectively. Fifteen participants in the control group received no training (66.7 ± 4.2 years). The TUG, TUGcog, and TUGman were measured in seconds at baseline, after the 12-week training, and after the 12-week follow-up. During the preliminary experiment, ten participants (67.0 ± 6.9 years) completed the three TUG measures 1/week for 5 weeks.

RESULTS

Both the BMT and BMT + C groups, but not the control group, exhibited significantly faster TUG, TUGcog, and TUGman after the intervention and maintained these improvements at the 12-week follow-up. No differences between the BMT and BMT + C groups emerged. The preliminary experiment showed that the three TUG measures were stable across five testing sessions.

DISCUSSION AND CONCLUSION

Both training groups improved functional mobility after the interventions and sustained these improvements over 12 weeks. This is likely not a function of repeating the TUG, TUGcog, and TUGman tests since no repeated exposure effect was shown.

Eccentric versus traditional resistance exercise for older adult fallers in the community: a randomized trial within a multi-component fall reduction program

BACKGROUND

Addressing muscle deficits within a multi-component exercise fall reduction program is a priority, especially for the highest risk older adults, i.e., those who have fallen previously. Eccentric resistance exercise with its high-force producing potential, at a low energetic cost, may be ideally-suited to address muscle impairments in this population. The purpose of this study was to compare the effects of resistance exercise via negative, eccentrically-induced, work (RENEW) versus traditional (TRAD) resistance exercise on mobility, balance confidence, muscle power and cross sectional area, as well as the number of days high fall risk older adults survived without a fall event over a 1 year period.

METHODS

Randomized, two group, four time point (over 1 year) clinical trial testing RENEW versus TRAD as part of a 3 month multi-component exercise fall reduction program (MCEFRP). Primary outcomes of mobility, balance confidence, muscle power output and cross sectional area were analyzed using mixed effects modeling. The secondary outcomes of days to fall and days to near-fall were analyzed using survival analysis.

RESULTS

The MCEFRP did have an effect on fall risk factors considered reversible with exercise interventions though there was no differential effect of RENEW versus TRAD (p = 0.896) on mobility, balance confidence, muscle power and cross sectional area. There were also no group differences in the number of days survived without a fall (p = 0.565) or near-fall (p = 0.678). Despite 100% of participants having at least one fall in the year prior to the MCEFRP, however, after 3 months of exercise and 9 months of follow-up <50% had experienced a fall or near fall.

CONCLUSIONS

There were no differential effects of RENEW or TRAD as components of a MCEFRP on the primary or secondary outcomes. The two modes of resistance exercise had identical effects on fall risk and fall-free survival.

TRIAL REGISTRATION

NCT01080196 ; March 2, 2010 (retrospectively registered).

Skeletal muscle functional and structural adaptations after eccentric overload flywheel resistance training: a systematic review and meta-analysis

OBJECTIVES

The purpose of this meta-analysis was to examine the effect of flywheel (FW) resistance training with Eccentric Overload (FW-EOT) on muscle size and functional capacities (i.e. strength and power) in athletes and healthy subjects, and to compare FW-induced adaptations with those triggered by traditional resistance exercise interventions.

DESIGN

A systematic review and meta-analysis of randomised controlled trials.

METHODS

A search of electronic databases [PubMed, MEDLINE (SportDiscus), Web of Science, Scopus and PEDro] was conducted to identify all publications employing FW-EOT up to April 30, 2016. Outcomes were analyzed as continuous outcomes using a random effects model to calculate a standardized mean difference (SMD) and 95% CI. A total of 9 studies with 276 subjects and 92 effect sizes met the inclusion criteria and were included in the statistical analyses.

RESULTS

The overall pooled estimate from the main effects analysis was 0.63 (95% CI 0.49-0.76) with a significant (p<0.001) Z overall effect of 9.17. No significant heterogeneity (p value=0.78) was found. The meta-analysis showed significant differences between FW-EOT vs. conventional resistance training in concentric and eccentric strength, muscle power, muscle hypertrophy, vertical jump height and running speed, favoring FW-EOT.

CONCLUSIONS

This meta-analysis provides evidence supporting the superiority of FW-EOT, compared with traditional weight-stack exercise, to promote skeletal muscle adaptations in terms of strength, power and size in healthy subjects and athletes.

The effects of exercise on muscle strength, body composition, physical functioning and the inflammatory profile of older adults: a systematic review

PURPOSE OF REVIEW

This systematic review reports the most recent literature regarding the effects of physical exercise on muscle strength, body composition, physical functioning and inflammation in older adults. All articles were assessed for methodological quality and where possible effect size was calculated.

RECENT FINDINGS

Thirty-four articles were included - four involving frail, 24 healthy and five older adults with a specific disease. One reported on both frail and nonfrail patients. Several types of exercise were used: resistance training, aerobic training, combined resistance training and aerobic training and others. In frail older persons, moderate-to-large beneficial exercise effects were noted on inflammation, muscle strength and physical functioning. In healthy older persons, effects of resistance training (most frequently investigated) on inflammation or muscle strength can be influenced by the exercise modalities (intensity and rest interval between sets). Muscle strength seemed the most frequently used outcome measure, with moderate-to-large effects obtained regardless the exercise intervention studied. Similar effects were found in patients with specific diseases.

SUMMARY

Exercise has moderate-to-large effects on muscle strength, body composition, physical functioning and inflammation in older adults. Future studies should focus on the influence of specific exercise modalities and target the frail population more.

The effects of muscle action, repetition duration, and loading strategies of a whole-body, progressive resistance training programme on muscular performance and body composition in trained males and females

Research has produced equivocal results with regard to eccentric (ECC) only compared with traditional concentric/eccentric resistance training (RT). When considered in relation to load- and repetition duration-accentuated (ECC) training as well as the use of isokinetic and isoinertial training methods, there is a relative dearth of literature considering multi-joint, multi-exercise RT interventions. The present study considered 59 male and female participants randomly divided in to 3 sex counterbalanced groups; ECC only (ECC, n = 20), repetition duration-accentuated ECC (ECC-A, n = 20), and traditional (CON, n = 19) performing full-body, effort matched RT programmes for 2 days·week−1 for 10 weeks. Outcomes were muscular performance, including absolute muscular endurance and predicted 1-repetition maximum, in addition to body composition. No significant between-groups differences were identified for change in muscular performance measures for leg press or chest press exercises, or for body composition changes. Analyses revealed a significantly greater improvement for CON compared with ECC groups (p < 0.05) for change in absolute muscular endurance for the pull-down exercise. Effect sizes for muscular performance changes were moderate to large for all groups and exercises (0.75–2.00). The present study supports previous research that ECC-only training produces similar improvements in muscular performance to traditional training where intensity of effort is controlled. Data herein further supports the use of uncomplicated, low-volume RT to momentary failure as an efficacious method of improving muscular performance in trained persons.

Greater Strength Gains after Training with Accentuated Eccentric than Traditional Isoinertial Loads in Already Strength-Trained Men

As training experience increases it becomes more challenging to induce further neuromuscular adaptation. Consequently, strength trainers seek alternative training methods in order to further increase strength and muscle mass. One method is to utilize accentuated eccentric loading, which applies a greater external load during the eccentric phase of the lift as compared to the concentric phase. Based upon this practice, the purpose of this study was to determine the effects of 10 weeks of accentuated eccentric loading vs. traditional isoinertial resistance training in strength-trained men. Young (22 ± 3 years, 177 ± 6 cm, 76 ± 10 kg, n = 28) strength-trained men (2.6 ± 2.2 years experience) were allocated to concentric-eccentric resistance training in the form of accentuated eccentric load (eccentric load = concentric load + 40%) or traditional resistance training, while the control group continued their normal unsupervised training program. Both intervention groups performed three sets of 6-RM (session 1) and three sets of 10-RM (session 2) bilateral leg press and unilateral knee extension exercises per week. Maximum force production was measured by unilateral isometric (110° knee angle) and isokinetic (concentric and eccentric 30°.s⁻¹) knee extension tests, and work capacity was measured by a knee extension repetition-to-failure test. Muscle mass was assessed using panoramic ultrasonography and dual-energy x-ray absorptiometry. Surface electromyogram amplitude normalized to maximum M-wave and the twitch interpolation technique were used to examine maximal muscle activation. After training, maximum isometric torque increased significantly more in the accentuated eccentric load group than control (18 ± 10 vs. 1 ± 5%, p < 0.01), which was accompanied by an increase in voluntary activation (3.5 ± 5%, p < 0.05). Isokinetic eccentric torque increased significantly after accentuated eccentric load training only (10 ± 9%, p < 0.05), whereas concentric torque increased equally in both the accentuated eccentric load (10 ± 9%, p < 0.01) and traditional (9 ± 6%, p < 0.01) resistance training groups; however, the increase in the accentuated eccentric load group was significantly greater (p < 0.05) than control (1 ± 7%). Knee extension repetition-to-failure improved in the accentuated eccentric load group only (28%, p < 0.05). Similar increases in muscle mass occurred in both intervention groups. In summary, accentuated eccentric load training led to greater increases in maximum force production, work capacity and muscle activation, but not muscle hypertrophy, in strength-trained individuals.