Background
Resistance training (RT) is an intervention frequently used to improve muscle strength and morphology in old age. However, evidence-based, dose–response relationships regarding specific RT ...variables (e.g., training period, frequency, intensity, volume) are unclear in healthy old adults.
Objectives
The aims of this systematic review and meta-analysis were to determine the general effects of RT on measures of muscle strength and morphology and to provide dose–response relationships of RT variables through an analysis of randomized controlled trials (RCTs) that could improve muscle strength and morphology in healthy old adults.
Data Sources
A computerized, systematic literature search was performed in the electronic databases PubMed, Web of Science, and The Cochrane Library from January 1984 up to June 2015 to identify all RCTs related to RT in healthy old adults.
Study Eligibility Criteria
The initial search identified 506 studies, with a final yield of 25 studies. Only RCTs that examined the effects of RT in adults with a mean age of 65 and older were included. The 25 studies quantified at least one measure of muscle strength or morphology and sufficiently described training variables (e.g., training period, frequency, volume, intensity).
Study Appraisal and Synthesis Methods
We quantified the overall effects of RT on measures of muscle strength and morphology by computing weighted between-subject standardized mean differences (SMD
bs
) between intervention and control groups. We analyzed the data for the main outcomes of one-repetition maximum (1RM), maximum voluntary contraction under isometric conditions (MVC), and muscle morphology (i.e., cross-sectional area or volume or thickness of muscles) and assessed the methodological study quality by Physiotherapy Evidence Database (PEDro) scale. Heterogeneity between studies was assessed using
I
2
and
χ
2
statistics. A random effects meta-regression was calculated to explain the influence of key training variables on the effectiveness of RT in terms of muscle strength and morphology. For meta-regression, training variables were divided into the following subcategories: volume, intensity, and rest. In addition to meta-regression, dose–response relationships were calculated independently for single training variables (e.g., training frequency).
Results
RT improved muscle strength substantially (mean SMD
bs
= 1.57; 25 studies), but had small effects on measures of muscle morphology (mean SMD
bs
= 0.42; nine studies). Specifically, RT produced large effects in both 1RM of upper (mean SMD
bs
= 1.61; 11 studies) and lower (mean SMD
bs
= 1.76; 19 studies) extremities and a medium effect in MVC of lower (mean SMD
bs
= 0.76; four studies) extremities. Results of the meta-regression revealed that the variables “training period” (
p
= 0.04) and “intensity” (
p
< 0.01) as well as “total time under tension” (
p
< 0.01) had significant effects on muscle strength, with the largest effect sizes for the longest training periods (mean SMD
bs
= 2.34; 50–53 weeks), intensities of 70–79 % of the 1RM (mean SMD
bs
= 1.89), and total time under tension of 6.0 s (mean SMD
bs
= 3.61). A tendency towards significance was found for rest in between sets (
p
= 0.06), with 60 s showing the largest effect on muscle strength (mean SMD
bs
= 4.68; two studies). We also determined the independent effects of the remaining training variables on muscle strength. The following independently computed training variables are most effective in improving measures of muscle strength: a training frequency of two sessions per week (mean SMD
bs
= 2.13), a training volume of two to three sets per exercise (mean SMD
bs
= 2.99), seven to nine repetitions per set (mean SMD
bs
= 1.98), and a rest of 4.0 s between repetitions (SMD
bs
= 3.72). With regard to measures of muscle morphology, the small number of identified studies allowed us to calculate meta-regression for the subcategory training volume only. No single training volume variable significantly predicted RT effects on measures of muscle morphology. Additional training variables were independently computed to detect the largest effect for the single training variable. A training period of 50–53 weeks, a training frequency of three sessions per week, a training volume of two to three sets per exercise, seven to nine repetitions per set, a training intensity from 51 to 69 % of the 1RM, a total time under tension of 6.0 s, a rest of 120 s between sets, and a rest of 2.5 s between repetitions turned out to be most effective.
Limitations
The current results must be interpreted with caution because of the poor overall methodological study quality (mean PEDro score 4.6 points) and the considerable large heterogeneity (
I
2
= 80 %,
χ
2
= 163.1,
df
= 32,
p
< 0.01) for muscle strength. In terms of muscle morphology, our search identified nine studies only, which is why we consider our findings preliminary. While we were able to determine a dose–response relationship based on specific individual training variables with respect to muscle strength and morphology, it was not possible to ascertain any potential interactions between these variables. We recognize the limitation that the results may not represent one general dose–response relationship.
Conclusions
This systematic literature review and meta-analysis confirmed the effectiveness of RT on specific measures of upper and lower extremity muscle strength and muscle morphology in healthy old adults. In addition, we were able to extract dose–response relationships for key training variables (i.e., volume, intensity, rest), informing clinicians and practitioners to design effective RTs for muscle strength and morphology. Training period, intensity, time under tension, and rest in between sets play an important role in improving muscle strength and morphology and should be implemented in exercise training programs targeting healthy old adults. Still, further research is needed to reveal optimal dose–response relationships following RT in healthy as well as mobility limited and/or frail old adults.
Balance and resistance training can improve healthy older adults' balance and muscle strength. Delivering such exercise programs at home without supervision may facilitate participation for older ...adults because they do not have to leave their homes. To date, no systematic literature analysis has been conducted to determine if supervision affects the effectiveness of these programs to improve healthy older adults' balance and muscle strength/power.
The objective of this systematic review and meta-analysis was to quantify the effectiveness of supervised vs. unsupervised balance and/or resistance training programs on measures of balance and muscle strength/power in healthy older adults. In addition, the impact of supervision on training-induced adaptive processes was evaluated in the form of dose-response relationships by analyzing randomized controlled trials that compared supervised with unsupervised trials.
A computerized systematic literature search was performed in the electronic databases PubMed, Web of Science, and SportDiscus to detect articles examining the role of supervision in balance and/or resistance training in older adults.
The initially identified 6041 articles were systematically screened. Studies were included if they examined balance and/or resistance training in adults aged ≥65 years with no relevant diseases and registered at least one behavioral balance (e.g., time during single leg stance) and/or muscle strength/power outcome (e.g., time for 5-Times-Chair-Rise-Test). Finally, 11 studies were eligible for inclusion in this meta-analysis.
Weighted mean standardized mean differences between subjects (SMD
) of supervised vs. unsupervised balance/resistance training studies were calculated. The included studies were coded for the following variables: number of participants, sex, age, number and type of interventions, type of balance/strength tests, and change (%) from pre- to post-intervention values. Additionally, we coded training according to the following modalities: period, frequency, volume, modalities of supervision (i.e., number of supervised/unsupervised sessions within the supervised or unsupervised training groups, respectively). Heterogeneity was computed using I
and χ
statistics. The methodological quality of the included studies was evaluated using the Physiotherapy Evidence Database scale.
Our analyses revealed that in older adults, supervised balance/resistance training was superior compared with unsupervised balance/resistance training in improving measures of static steady-state balance (mean SMD
= 0.28, p = 0.39), dynamic steady-state balance (mean SMD
= 0.35, p = 0.02), proactive balance (mean SMD
= 0.24, p = 0.05), balance test batteries (mean SMD
= 0.53, p = 0.02), and measures of muscle strength/power (mean SMD
= 0.51, p = 0.04). Regarding the examined dose-response relationships, our analyses showed that a number of 10-29 additional supervised sessions in the supervised training groups compared with the unsupervised training groups resulted in the largest effects for static steady-state balance (mean SMD
= 0.35), dynamic steady-state balance (mean SMD
= 0.37), and muscle strength/power (mean SMD
= 1.12). Further, ≥30 additional supervised sessions in the supervised training groups were needed to produce the largest effects on proactive balance (mean SMD
= 0.30) and balance test batteries (mean SMD
= 0.77). Effects in favor of supervised programs were larger for studies that did not include any supervised sessions in their unsupervised programs (mean SMD
: 0.28-1.24) compared with studies that implemented a few supervised sessions in their unsupervised programs (e.g., three supervised sessions throughout the entire intervention program; SMD
: -0.06 to 0.41).
The present findings have to be interpreted with caution because of the low number of eligible studies and the moderate methodological quality of the included studies, which is indicated by a median Physiotherapy Evidence Database scale score of 5. Furthermore, we indirectly compared dose-response relationships across studies and not from single controlled studies.
Our analyses suggest that supervised balance and/or resistance training improved measures of balance and muscle strength/power to a greater extent than unsupervised programs in older adults. Owing to the small number of available studies, we were unable to establish a clear dose-response relationship with regard to the impact of supervision. However, the positive effects of supervised training are particularly prominent when compared with completely unsupervised training programs. It is therefore recommended to include supervised sessions (i.e., two out of three sessions/week) in balance/resistance training programs to effectively improve balance and muscle strength/power in older adults.
Biomechanics (ISSN 2673-7078) is an international, peer-reviewed, open access journal covering all aspects of biomechanics, which can be described as the application of principles and methods of ...mechanics to the quantitative study of biological systems ...
Background
The effects of balance training (BT) in older adults on proxies of postural control and mobility are well documented in the literature. However, evidence-based dose–response relationships ...in BT modalities (i.e., training period, training frequency, training volume) have not yet been established in healthy older adults.
Objectives
The objectives of this systematic literature review and meta-analysis are to quantify BT intervention effects and to additionally characterize dose–response relationships of BT modalities (e.g., training period, training frequency) through the analysis of randomized controlled trials (RCTs) that could maximize improvements in balance performance in healthy community-dwelling older adults.
Data Sources
A computerized systematic literature search was performed in the electronic databases PubMed and Web of Science from January 1985 up to January 2015 to capture all articles related to BT in healthy old community-dwelling adults.
Study Eligibility Criteria
A systematic approach was used to evaluate the 345 articles identified for initial review. Only RCTs were included if they investigated BT in healthy community-dwelling adults aged ≥65 years and tested at least one behavioral balance performance outcome (e.g., center of pressure displacements during single-leg stance). In total, 23 studies met the inclusionary criteria for review.
Study Appraisal and Synthesis Methods
Weighted mean standardized mean differences between subjects (SMD
bs
) of the intervention-induced adaptations in balance performance were calculated using a random-effects model and tested for an overall intervention effect relative to passive controls. The included studies were coded for the following criteria: training modalities (i.e., training period, training frequency, training volume) and balance outcomes static/dynamic steady-state (i.e., maintaining a steady position during standing and walking), proactive balance (i.e., anticipation of a predicted perturbation), reactive balance (i.e., compensation of an unpredicted perturbation) as well as balance test batteries (i.e., combined testing of different balance components as for example the Berg Balance Scale). Heterogeneity between studies was assessed using
I
2
and Chi
2
-statistics. The methodological quality of each study was tested by means of the Physiotherapy Evidence Database (PEDro) Scale.
Results
Weighted mean SMD
bs
showed that BT is an effective means to improve static steady-state (mean SMD
bs
= 0.51), dynamic steady-state (mean SMD
bs
= 0.44), proactive (mean SMD
bs
= 1.73), and reactive balance (mean SMD
bs
= 1.01) as well as the performance in balance test batteries (mean SMD
bs
= 1.52) in healthy older adults. Our analyses regarding dose–response relationships in BT revealed that a training period of 11–12 weeks (mean SMD
bs
= 1.26), a frequency of three training sessions per week (mean SMD
bs
= 1.20), a total number of 36–40 training sessions (mean SMD
bs
= 1.39), a duration of a single training session of 31–45 min (mean SMD
bs
= 1.19), and a total duration of 91–120 min of BT per week (mean SMD
bs
= 1.93) of the applied training modalities is most effective in improving overall balance performance. However, it has to be noted that effect sizes for the respective training modalities were computed independently (i.e., modality specific). Because of the small number of studies that reported detailed information on training volume (i.e., number of exercises per training session, number of sets and/or repetitions per exercise, duration of single-balance exercises) dose–response relationships were not computed for these parameters.
Limitations
The present findings have to be interpreted with caution because we indirectly compared dose–response relationships across studies using SMD
bs
and not in a single controlled study as it is difficult to separate the impact of a single training modality (e.g., training frequency) from that of the others. Moreover, the quality of the included studies was rather limited with a mean PEDro score of 5 and the heterogeneity between studies was considerable (i.e.,
I
2
= 76–92 %).
Conclusions
Our detailed analyses revealed that BT is an effective means to improve proxies of static/dynamic steady-state, proactive, and reactive balance as well as performance in balance test batteries in healthy older adults. Furthermore, we were able to establish effective BT modalities to improve balance performance in healthy older adults. Thus, practitioners and therapists are advised to consult the identified dose–response relationships of this systematic literature review and meta-analysis. However, further research of high methodologic quality is needed to determine (1) dose–response relationships of BT in terms of detailed information on training volume (e.g., number of exercises per training session) and (2) a feasible and effective method to regulate training intensity in BT.
The aging process results in a number of functional (e.g., deficits in balance and strength/power performance), neural (e.g., loss of sensory/motor neurons), muscular (e.g., atrophy of type-II muscle ...fibers in particular), and bone-related (e.g., osteoporosis) deteriorations. Traditionally, balance and/or lower extremity resistance training were used to mitigate these age-related deficits. However, the effects of resistance training are limited and poorly translate into improvements in balance, functional tasks, activities of daily living, and fall rates. Thus, it is necessary to develop and design new intervention programs that are specifically tailored to counteract age-related weaknesses. Recent studies indicate that measures of trunk muscle strength (TMS) are associated with variables of static/dynamic balance, functional performance, and falls (i.e., occurrence, fear, rate, and/or risk of falls). Further, there is preliminary evidence in the literature that core strength training (CST) and Pilates exercise training (PET) have a positive influence on measures of strength, balance, functional performance, and falls in older adults.
The objectives of this systematic literature review are: (a) to report potential associations between TMS/trunk muscle composition and balance, functional performance, and falls in old adults, and (b) to describe and discuss the effects of CST/PET on measures of TMS, balance, functional performance, and falls in seniors.
A systematic approach was employed to capture all articles related to TMS/trunk muscle composition, balance, functional performance, and falls in seniors that were identified using the electronic databases PubMed and Web of Science (1972 to February 2013).
A systematic approach was used to evaluate the 582 articles identified for initial review. Cross-sectional (i.e., relationship) or longitudinal (i.e., intervention) studies were included if they investigated TMS and an outcome-related measure of balance, functional performance, and/or falls. In total, 20 studies met the inclusionary criteria for review.
Longitudinal studies were evaluated using the Physiotherapy Evidence Database (PEDro) scale. Effect sizes (ES) were calculated whenever possible. For ease of discussion, the 20 articles were separated into three groups i.e., cross-sectional (n = 6), CST (n = 9), PET (n = 5).
The cross-sectional studies reported small-to-medium correlations between TMS/trunk muscle composition and balance, functional performance, and falls in older adults. Further, CST and/or PET proved to be feasible exercise programs for seniors with high-adherence rates. Age-related deficits in measures of TMS, balance, functional performance, and falls can be mitigated by CST (mean strength gain = 30 %, mean effect size = 0.99; mean balance/functional performance gain = 23 %, mean ES = 0.88) and by PET (mean strength gain = 12 %, mean ES = 0.52; mean balance/functional performance gain = 18 %, mean ES = 0.71).
Given that the mean PEDro quality score did not reach the predetermined cut-off of ≥6 for the intervention studies, there is a need for more high-quality studies to explicitly identify the relevance of CST and PET to the elderly population.
Core strength training and/or PET can be used as an adjunct or even alternative to traditional balance and/or resistance training programs for old adults. Further, CST and PET are easy to administer in a group setting or in individual fall preventive or rehabilitative intervention programs because little equipment and space is needed to perform such exercises.
Despite controversy on the correlation between p53 accumulation and TP53 mutational status, immunohistochemical (IHC) detection of overexpressed protein has long been used as a surrogate method for ...mutation analysis. The aim of our study was to characterise the IHC expression features of TP53 somatic mutations and define their occurrence in human cancers. A large-scale database analysis was conducted in the IARC TP53 Database (R17); 7878 mutations with IHC features were retrieved representing 60 distinct tumour sites. The majority of the alterations were immunopositive (p <0.001). Sex was known for 4897 mutations showing a female dominance (57.2%) and females carrying negative mutations were significantly younger. TP53 mutations were divided into three IHC groups according to mutation frequency and IHC positivity. Each group had female dominance. Among the IHC groups, significant correlations were observed with age at diagnosis in breast, bladder, liver, haematopoietic system and head & neck cancers. An increased likelihood of false negative IHC associated with rare nonsense mutations was observed in certain tumour sites. Our study demonstrates that p53 immunopositivity largely correlates with TP53 mutational status but expression is absent in certain mutation types.Besides, describing the complex IHC expression of TP53 somatic mutations, our results reveal some caveats for the diagnostic practice.
Semi-quantitative scoring is a method that is widely used to estimate the quantity of proteins on chromogen-labelled immunohistochemical (IHC) tissue sections. However, it suffers from several ...disadvantages, including its lack of objectivity and the fact that it is a time-consuming process. Our aim was to test a recently established artificial intelligence (AI)-aided digital image analysis platform, Pathronus, and to compare it to conventional scoring by five observers on chromogenic IHC-stained slides belonging to three experimental groups. Because Pathronus operates on grayscale 0-255 values, we transformed the data to a seven-point scale for use by pathologists and scientists. The accuracy of these methods was evaluated by comparing statistical significance among groups with quantitative fluorescent IHC reference data on subsequent tissue sections. The pairwise inter-rater reliability of the scoring and converted Pathronus data varied from poor to moderate with Cohen's kappa, and overall agreement was poor within every experimental group using Fleiss' kappa. Only the original and converted that were obtained from Pathronus original were able to reproduce the statistical significance among the groups that were determined by the reference method. In this study, we present an AI-aided software that can identify cells of interest, differentiate among organelles, protein specific chromogenic labelling, and nuclear counterstaining after an initial training period, providing a feasible and more accurate alternative to semi-quantitative scoring.
This systematic review and meta-analysis examined the dose-response relationship between exercise and cognitive function in older adults with and without cognitive impairments. We included ...single-modality randomized controlled aerobic, anaerobic, multicomponent or psychomotor exercise trials that quantified training frequency, session and program duration and specified intensity quantitatively or qualitatively. We defined total exercise duration in minutes as the product of program duration, session duration, and frequency. For each study, we grouped test-specific Hedges' d (n = 163) and Cohen's d (n = 23) effect sizes in the domains Global cognition, Executive function and Memory. We used multilevel mixed-effects models to investigate dose-related predictors of exercise effects. In healthy older adults (n = 23 studies), there was a small positive effect of exercise on executive function (d = 0.27) and memory (d = 0.24), but dose-parameters did not predict the magnitude of effect sizes. In older adults with cognitive impairments (n = 13 studies), exercise had a moderate positive effect on global cognition (d = 0.37). For older adults with cognitive impairments, we found evidence for exercise programs with a short session duration and high frequency to predict higher effect sizes (d = 0.43-0.50). In healthy older adults, dose-parameters did not predict the magnitude of exercise effects on cognition. For older adults with cognitive impairments, exercise programs with shorter session duration and higher frequency may generate the best cognitive results. Studies are needed in which different exercise doses are directly compared among randomized subjects or conditions.
Background
Habitual walking speed predicts many clinical conditions later in life, but it declines with age. However, which particular exercise intervention can minimize the age-related gait speed ...loss is unclear.
Purpose
Our objective was to determine the effects of strength, power, coordination, and multimodal exercise training on healthy old adults’ habitual and fast gait speed.
Methods
We performed a computerized systematic literature search in PubMed and Web of Knowledge from January 1984 up to December 2014. Search terms included ‘Resistance training’, ‘power training’, ‘coordination training’, ‘multimodal training’, and ‘gait speed (outcome term). Inclusion criteria were articles available in full text, publication period over past 30 years, human species, journal articles, clinical trials, randomized controlled trials, English as publication language, and subject age ≥65 years. The methodological quality of all eligible intervention studies was assessed using the Physiotherapy Evidence Database (PEDro) scale. We computed weighted average standardized mean differences of the intervention-induced adaptations in gait speed using a random-effects model and tested for overall and individual intervention effects relative to no-exercise controls.
Results
A total of 42 studies (mean PEDro score of 5.0 ± 1.2) were included in the analyses (2495 healthy old adults; age 74.2 years 64.4–82.7; body mass 69.9 ± 4.9 kg, height 1.64 ± 0.05 m, body mass index 26.4 ± 1.9 kg/m
2
, and gait speed 1.22 ± 0.18 m/s). The search identified only one power training study, therefore the subsequent analyses focused only on the effects of resistance, coordination, and multimodal training on gait speed. The three types of intervention improved gait speed in the three experimental groups combined (
n
= 1297) by 0.10 m/s (±0.12) or 8.4 % (±9.7), with a large effect size (ES) of 0.84. Resistance (24 studies;
n
= 613; 0.11 m/s; 9.3 %; ES: 0.84), coordination (eight studies,
n
= 198; 0.09 m/s; 7.6 %; ES: 0.76), and multimodal training (19 studies;
n
= 486; 0.09 m/s; 8.4 %, ES: 0.86) increased gait speed statistically and similarly.
Conclusions
Commonly used exercise interventions can functionally and clinically increase habitual and fast gait speed and help slow the loss of gait speed or delay its onset.
Balance training (BT) has been used for the promotion of balance and sports-related skills as well as for prevention and rehabilitation of lower extremity sport injuries. However, evidence-based ...dose-response relationships in BT parameters have not yet been established.
The objective of this systematic literature review and meta-analysis was to determine dose-response relationships in BT parameters that lead to improvements in balance in young healthy adults with different training status.
A computerized systematic literature search was performed in the electronic databases PubMed, Web of Knowledge, and SPORTDiscus from January 1984 up to May 2014 to capture all articles related to BT in young healthy adults.
A systematic approach was used to evaluate the 596 articles identified for initial review. Only randomized controlled studies were included if they investigated BT in young healthy adults (16-40 years) and tested at least one behavioral balance performance outcome. In total, 25 studies met the inclusion criteria for review.
Studies were evaluated using the physiotherapy evidence database (PEDro) scale. Within-subject effect sizes (ESdw) and between-subject effect sizes (ESdb) were calculated. The included studies were coded for the following criteria: training status (elite athletes, sub-elite athletes, recreational athletes, untrained subjects), training modalities (training period, frequency, volume, etc.), and balance outcome (test for the assessment of steady-state, proactive, and reactive balance).
Mean ESdb demonstrated that BT is an effective means to improve steady-state (ESdb = 0.73) and proactive balance (ESdb = 0.92) in healthy young adults. Studies including elite athletes showed the largest effects (ESdb = 1.29) on measures of steady-state balance as compared with studies analyzing sub-elite athletes (ESdb = 0.32), recreational athletes (ESdb = 0.69), and untrained subjects (ESdb = 0.82). Our analyses regarding dose-response relationships in BT revealed that a training period of 11-12 weeks (ESdb = 1.09), a training frequency of three (mean ESdb = 0.72) or six (single ESdb = 1.84) sessions per week, at least 16-19 training sessions in total (ESdb = 1.12), a duration of 11-15 min for a single training session (ESdb = 1.11), four exercises per training session (ESdb = 1.29), two sets per exercise (ESdb = 1.63), and a duration of 21-40 s for a single BT exercise (ESdb = 1.06) is most effective in improving measures of steady-state balance. Due to a small number of studies, dose-response relationships of BT for measures of proactive and reactive balance could not be qualified.
The present findings must be interpreted with caution because it is difficult to separate the impact of a single training modality (e.g., training frequency) from that of the others. Moreover, the quality of the included studies was rather limited, with a mean PEDro score of 5.
Our detailed analyses revealed effective BT parameters for the improvement of steady-state balance. Thus, practitioners and coaches are advised to consult the identified dose-response relationships of this systematic literature review and meta-analysis to implement effective BT protocols in clinical and sports-related contexts. However, further research of high methodological quality is needed to (1) determine dose-response relationships of BT for measures of proactive and reactive balance, (2) define effective sequencing protocols in BT (e.g., BT before or after a regular training session), (3) discern the effects of detraining, and (4) develop a feasible and effective method to regulate training intensity in BT.
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