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Sports Medicine (Auckland, N.Z.) Jan 2019The combination of low-load resistance training with blood flow restriction (BFR) has recently been shown to promote muscular adaptations in various populations. To... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The combination of low-load resistance training with blood flow restriction (BFR) has recently been shown to promote muscular adaptations in various populations. To date, however, evidence is sparse on how this training regimen influences muscle mass and strength in older adults.
PURPOSE
The purpose of this systematic review and meta-analysis was to quantitatively identify the effects of low-load BFR (LL-BFR) training on muscle mass and strength in older individuals in comparison with conventional resistance training programmes. Additionally, the effectiveness of walking with and without BFR was assessed.
METHODS
A PRISMA-compliant systematic review and meta-analysis was conducted. The systematic literature research was performed in the following electronic databases from inception to 1 June 2018: PubMed, Web of Science, Scopus, CINAHL, SPORTDiscus and CENTRAL. Subsequently, a random-effects meta-analysis with inverse variance weighting was conducted.
RESULTS
A total of 2658 articles were screened, and 11 studies with a total population of N = 238 were included in the meta-analysis. Our results revealed that during both low-load training and walking, the addition of BFR elicits significantly greater improvements in muscular strength with pooled effect sizes (ES) of 2.16 (95% CI 1.61 to 2.70) and 3.09 (95% CI 2.04 to 4.14), respectively. Muscle mass was also increased when comparing walking with and without BFR [ES 1.82 (95% CI 1.32 to 2.32)]. In comparison with high-load training, LL-BFR promotes similar muscle hypertrophy [ES 0.21 (95% CI - 0.14 to 0.56)] but lower strength gains [ES - 0.42 (95% CI - 0.70 to - 0.14)].
CONCLUSION
This systematic review and meta-analysis reveals that LL-BFR and walking with BFR is an effective interventional approach to stimulate muscle hypertrophy and strength gains in older populations. As BFR literature is still scarce with regard to potential moderator variables (e.g. sex, cuff pressure or training volume/frequency), further research is needed for strengthening the evidence for an effective application of LL-BFR training in older people.
Topics: Aged; Constriction; Humans; Muscle Strength; Muscle, Skeletal; Regional Blood Flow; Resistance Training; Walking
PubMed: 30306467
DOI: 10.1007/s40279-018-0994-1 -
Journal of Sport and Health Science May 2023For the past 30 years, the hamstring (H)-to-quadriceps (Q) (H:Q) torque ratio has been considered an important index of muscle strength imbalance around the knee joint.... (Review)
Review
BACKGROUND
For the past 30 years, the hamstring (H)-to-quadriceps (Q) (H:Q) torque ratio has been considered an important index of muscle strength imbalance around the knee joint. The purpose of this systematic review was to examine the value of H:Q torque ratio as an independent risk factor for hamstring and anterior cruciate ligament (ACL) injuries.
METHODS
Database searches were performed to identify all relevant articles in PubMed, MEDLINE, Cochrane Library, and Scopus. Prospective studies evaluating the conventional (concentric H:Q), functional (eccentric H: concentric Q), and mixed (eccentric H at 30°/s: concentric Q at 240°/s) H:Q ratios as risk factors for occurrence of hamstring muscle strain or ACL injury were considered. Risk of bias was assessed using the Quality In Prognosis Studies tool.
RESULTS
Eighteen included studies reported 585 hamstrings injuries in 2945 participants, and 5 studies documented 128 ACL injuries in 2772 participants. Best evidence synthesis analysis indicated that there is very limited evidence that H:Q strength ratio is an independent risk factor for hamstring and ACL injury, and this was not different between various ratio types. Methodological limitations and limited evidence for ACL injuries and some ratio types might have influenced these results.
CONCLUSION
The H:Q ratio has limited value for the prediction of ACL and hamstring injuries. Monitoring strength imbalances along with other modifiable factors during the entire competitive season may provide a better understanding of the association between H:Q ratio and injury.
Topics: Humans; Anterior Cruciate Ligament; Hamstring Muscles; Anterior Cruciate Ligament Injuries; Muscle, Skeletal; Torque; Prospective Studies; Leg Injuries
PubMed: 35065297
DOI: 10.1016/j.jshs.2022.01.002 -
Journal of Sports Sciences Jun 2019Training frequency is considered an important variable in the hypertrophic response to regimented resistance exercise. The purpose of this paper was to conduct a... (Meta-Analysis)
Meta-Analysis
How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of studies examining the effects of resistance training frequency.
Training frequency is considered an important variable in the hypertrophic response to regimented resistance exercise. The purpose of this paper was to conduct a systematic review and meta-analysis of experimental studies designed to investigate the effects of weekly training frequency on hypertrophic adaptations. Following a systematic search of PubMed/MEDLINE, Scoups, and SPORTDiscus databases, a total of 25 studies were deemed to meet inclusion criteria. Results showed no significant difference between higher and lower frequency on a volume-equated basis. Moreover, no significant differences were seen between frequencies of training across all categories when taking into account direct measures of growth, in those considered resistance-trained, and when segmenting into training for the upper body and lower body. Meta-regression analysis of non-volume-equated studies showed a significant effect favoring higher frequencies, although the overall difference in magnitude of effect between frequencies of 1 and 3+ days per week was modest. In conclusion, there is strong evidence that resistance training frequency does not significantly or meaningfully impact muscle hypertrophy when volume is equated. Thus, for a given training volume, individuals can choose a weekly frequency per muscle groups based on personal preference.
Topics: Adaptation, Physiological; Humans; Lower Extremity; Muscle Strength; Muscle, Skeletal; Resistance Training; Time Factors; Upper Extremity
PubMed: 30558493
DOI: 10.1080/02640414.2018.1555906 -
Pain Physician 2016Lumbar muscle dysfunction due to pain might be related to altered lumbar muscle structure. Macroscopically, muscle degeneration in low back pain (LBP) is characterized... (Review)
Review
BACKGROUND
Lumbar muscle dysfunction due to pain might be related to altered lumbar muscle structure. Macroscopically, muscle degeneration in low back pain (LBP) is characterized by a decrease in cross-sectional area and an increase in fat infiltration in the lumbar paraspinal muscles. In addition microscopic changes, such as changes in fiber distribution, might occur. Inconsistencies in results from different studies make it difficult to draw firm conclusions on which structural changes are present in the different types of non-specific LBP. Insights regarding structural muscle alterations in LBP are, however, important for prevention and treatment of non-specific LBP.
OBJECTIVE
The goal of this article is to review which macro- and/or microscopic structural alterations of the lumbar muscles occur in case of non-specific chronic low back pain (CLBP), recurrent low back pain (RLBP), and acute low back pain (ALBP).
STUDY DESIGN
Systematic review.
SETTING
All selected studies were case-control studies.
METHODS
A systematic literature search was conducted in the databases PubMed and Web of Science. Only full texts of original studies regarding structural alterations (atrophy, fat infiltration, and fiber type distribution) in lumbar muscles of patients with non-specific LBP compared to healthy controls were included. All included articles were scored on methodological quality.
RESULTS
Fifteen studies were found eligible after screening title, abstract, and full text for inclusion and exclusion criteria. In CLBP, moderate evidence of atrophy was found in the multifidus; whereas, results in the paraspinal and the erector spinae muscle remain inconclusive. Also moderate evidence occurred in RLBP and ALBP, where no atrophy was shown in any lumbar muscle. Conflicting results were seen in undefined LBP groups. Results concerning fat infiltration were inconsistent in CLBP. On the other hand, there is moderate evidence in RLBP that fat infiltration does not occur, although a larger muscle fat index was found in the erector spinae, multifidus, and paraspinal muscles, reflecting an increased relative amount of intramuscular lipids in RLBP. However, no studies were found investigating fat infiltration in ALBP. Restricted evidence indicates no abnormalities in fiber type in the paraspinal muscles in CLBP. No studies have examined fiber type in ALBP and RLBP.
LIMITATIONS
Lack of clarity concerning patient definitions, exact LBP symptoms, and applied methods.
CONCLUSIONS
The results indicate atrophy in CLBP in the multifidus and paraspinal muscles but not in the erector spinae. No atrophy was shown in RLBP and ALBP. Fat infiltration did not occur in RLBP, but results in CLBP were inconsistent. No abnormalities in fiber type in the paraspinal muscles were found in CLBP.
KEY WORDS
Low back pain, non-specific, chronic, recurrent, acute, muscle structure, fat infiltration, cross-sectional area, fiber type, review.
Topics: Humans; Low Back Pain; Lumbar Vertebrae; Lumbosacral Region; Muscle, Skeletal; Paraspinal Muscles
PubMed: 27676689
DOI: No ID Found -
Nutrients May 2022Sarcopenia negatively affects skeletal muscle mass and function in older adults. Omega-3 (ω-3) fatty acid supplementation, with or without resistance exercise training... (Meta-Analysis)
Meta-Analysis Review
Sarcopenia negatively affects skeletal muscle mass and function in older adults. Omega-3 (ω-3) fatty acid supplementation, with or without resistance exercise training (RET), is suggested to play a role as a therapeutic component to prevent or treat the negative effects of sarcopenia. A systematic review and meta-analysis were conducted on the impact of ω-3 fatty acid supplementation with or without RET on measures of muscle mass and function in older adults (≥55 y). The data sources included SPORTDiscus, PubMed, and Medline. All the study types involving ω-3 fatty acid supplementation on measures of muscle mass and function in older adults (without disease) were included. The mean differences (MDs) or standardized mean differences (SMDs) with 95% confidence intervals were calculated and pooled effects assessed. Sixteen studies (1660 females, 778 males) met our inclusion criteria and were included in the meta-analysis. ω-3 fatty acid supplementation did not impact lean tissue mass (SMD 0.09 [-0.10, 0.28]). Benefits were observed for lower body strength (SMD 0.54 [0.33, 0.75]), timed-up-and-go (MD 0.29 [0.23, 0.35]s), and 30-s sit-to-stand performance (MD 1.93 [1.59, 2.26] repetitions) but not walking performance (SMD -0.01 [-0.10, 0.07]) or upper body strength (SMD 0.05 [-0.04, 0.13]). Supplementing with ω-3 fatty acids may improve the lower-body strength and functionality in older adults.
Topics: Aged; Dietary Supplements; Fatty Acids, Omega-3; Female; Humans; Male; Muscle Strength; Muscle, Skeletal; Resistance Training; Sarcopenia
PubMed: 35684018
DOI: 10.3390/nu14112221 -
Journal of Sport Rehabilitation Sep 2017Gluteus medius rehabilitation is of critical importance given its role in pelvic and lower limb stability, and the known link between gluteus medius weakness and many... (Review)
Review
CONTEXT
Gluteus medius rehabilitation is of critical importance given its role in pelvic and lower limb stability, and the known link between gluteus medius weakness and many lower limb conditions.
OBJECTIVE
To systematically review the literature and present an evidence-based graduated series of exercises to progressively load gluteus medius.
EVIDENCE ACQUISITION
A systematic literature search was conducted in January 2016 to identify studies reporting gluteus medius muscle activity as a percentage of maximal volitional isometric contraction (MVIC), during rehabilitation exercises. Studies that investigated injury free participants were included. No restrictions were placed on the type or mode of exercise, though exercises that could not be accurately replicated or performed within an independent setting were excluded. Studies that did not normalize electromyographic activity to a side lying MVIC were excluded. Exercises were stratified based on exercise type and %MVIC: low (0% to 20%), moderate (21% to 40%), high (41% to 60%), and very high (> 61%).
EVIDENCE SYNTHESIS
20 studies were included in this review, reporting outcomes in 33 exercises (and a range of variations of the same exercise). Prone, quadruped, and bilateral bridge exercises generally produced low or moderate load. Specific hip abduction/rotation exercises were reported as moderate, high, or very high load. Unilateral stance exercises in the presence of contralateral limb movement were often high or very high load activities, while high variability existed across a range of functional weight-bearing exercises.
CONCLUSIONS
This review outlined a series of exercises commonly employed in a rehabilitation setting, stratified based on exercise type and the magnitude of gluteus medius muscular activation. This will assist clinicians in tailoring gluteus medius loading regimens to patients, from the early postoperative through to later stages of rehabilitation.
Topics: Buttocks; Electromyography; Exercise Therapy; Humans; Isometric Contraction; Muscle, Skeletal; Rotation; Thigh; Weight-Bearing
PubMed: 27632888
DOI: 10.1123/jsr.2016-0088 -
European Journal of Sport Science Feb 2021The objectives of this paper were to: (a) systematically review studies that explored the effects of exercise order (EO) on muscular strength and/or hypertrophy; (b)... (Meta-Analysis)
Meta-Analysis
The objectives of this paper were to: (a) systematically review studies that explored the effects of exercise order (EO) on muscular strength and/or hypertrophy; (b) pool their results using a meta-analysis; and (c) provide recommendations for the prescription of EO in resistance training (RT) programmes. A literature search was performed in four databases. Studies were included if they explored the effects of EO on dynamic muscular strength and/or muscle hypertrophy. The meta-analysis was performed using a random-effects model with Hedges' g effect size (ES). The methodological quality of studies was appraised using the TESTEX checklist. Eleven good-to-excellent methodological quality studies were included in the review. When all strength tests, that is, both in multi-joint (MJ) and single-joint (SJ) exercises were considered, there was no difference between the EOs (ES = -0.11; 0.306). However, there was a difference between the MJ-to-SJ and SJ-to-MJ orders for strength gains in the MJ exercises, favouring starting the exercise session with MJ exercises (ES = 0.32; 0.034), and the strength gains in the SJ exercises, favouring starting the exercise session with SJ exercises (ES = -0.58; 0.032). No significant effect of EO was observed for hypertrophy combining site-specific and indirect measures (ES = 0.03; 0.862). In conclusion, increases in muscular strength are the largest in the exercises performed at the beginning of an exercise session. For muscle hypertrophy, our meta-analysis indicated that both MJ-to-SJ and SJ-to-MJ EOs may produce similar results.
Topics: Humans; Hypertrophy; Muscle Strength; Muscle, Skeletal; Resistance Training
PubMed: 32077380
DOI: 10.1080/17461391.2020.1733672 -
Journal of Strength and Conditioning... Sep 2017Schoenfeld, BJ, Ogborn, DI, Vigotsky, AD, Franchi, MV, and Krieger, JW. Hypertrophic effects of concentric vs. eccentric muscle actions: A systematic review and... (Meta-Analysis)
Meta-Analysis Review
Schoenfeld, BJ, Ogborn, DI, Vigotsky, AD, Franchi, MV, and Krieger, JW. Hypertrophic effects of concentric vs. eccentric muscle actions: A systematic review and meta-analysis. J Strength Cond Res 31(9): 2599-2608, 2017-Controversy exists as to whether different dynamic muscle actions produce divergent hypertrophic responses. The purpose of this paper was to conduct a systematic review and meta-analysis of randomized controlled trials comparing the hypertrophic effects of concentric vs. eccentric training in healthy adults after regimented resistance training (RT). Studies were deemed eligible for inclusion if they met the following criteria: (a) were an experimental trial published in an English-language refereed journal; (b) directly compared concentric and eccentric actions without the use of external implements (i.e., blood pressure cuffs) and all other RT variables equivalent; (c) measured morphologic changes using biopsy, imaging (magnetic resonance imaging, computerized tomography, or ultrasound), bioelectrical impedance, and/or densitometry; (d) had a minimum duration of 6 weeks; and (e) used human participants without musculoskeletal injury or any health condition that could directly, or through the medications associated with the management of said condition, be expected to impact the hypertrophic response to resistance exercise. A systematic literature search determined that 15 studies met inclusion criteria. Results showed that eccentric muscle actions resulted in a greater effect size (ES) compared with concentric actions, but results did not reach statistical significance (ES difference = 0.25 ± 0.13; 95% confidence interval: -0.03 to 0.52; p = 0.076). The mean percent change in muscle growth across studies favored eccentric compared with concentric actions (10.0% vs. 6.8, respectively). The findings indicate the importance of including eccentric and concentric actions in a hypertrophy-oriented RT program, as both have shown to be effective in increasing muscle hypertrophy.
Topics: Adult; Biopsy; Electric Impedance; Exercise; Female; Humans; Magnetic Resonance Imaging; Male; Muscle, Skeletal; Randomized Controlled Trials as Topic; Resistance Training
PubMed: 28486337
DOI: 10.1519/JSC.0000000000001983 -
Journal of Strength and Conditioning... Feb 2021Romero-Parra, N, Cupeiro, R, Alfaro-Magallanes, VM, Rael, B, Rubio-Arias, JA, Peinado, AB, and Benito, PJ, IronFEMME Study Group. Exercise-induced muscle damage during... (Meta-Analysis)
Meta-Analysis
Romero-Parra, N, Cupeiro, R, Alfaro-Magallanes, VM, Rael, B, Rubio-Arias, JA, Peinado, AB, and Benito, PJ, IronFEMME Study Group. Exercise-induced muscle damage during the menstrual cycle: A systematic review and meta-analysis. J Strength Cond Res 35(2): 549-561, 2021-A strenuous bout of exercise could trigger damage of muscle tissue, and it is not clear how sex hormone fluctuations occurring during the menstrual cycle (MC) affect this response. The aims of this study were to systematically search and assess studies that have evaluated exercise-induced muscle damage (EIMD) in eumenorrheic women over the MC and to perform a meta-analysis to quantify which MC phases display the muscle damage response. The guidelines of the Preferred Reported Items for Systematic Reviews and Meta-Analysis were followed. A total of 19 articles were analyzed in the quantitative synthesis. Included studies examined EIMD in at least one phase of the following MC phases: early follicular phase (EFP), late follicular phase (LFP), or midluteal phase (MLP). The meta-analysis demonstrated differences between MC phases for delayed onset muscle soreness (DOMS) and strength loss (p < 0.05), whereas no differences were observed between MC phases for creatine kinase. The maximum mean differences between pre-excercise and post-exercise for DOMS were EFP: 6.57 (4.42, 8.71), LFP: 5.37 (2.10, 8.63), and MLP: 3.08 (2.22, 3.95), whereas for strength loss were EFP: -3.46 (-4.95, -1.98), LFP: -1.63 (-2.36, -0.89), and MLP: -0.72 (-1.07, -0.36) (p < 0.001). In conclusion, this meta-analysis suggests that hormone fluctuations throughout the MC affect EIMD in terms of DOMS and strength loss. Lower training loads or longer recovery periods could be considered in the EFP, when sex hormone concentrations are lower and women may be more vulnerable to muscle damage, whereas strength conditioning loads could be enhanced in the MLP.
Topics: Exercise; Female; Follicular Phase; Humans; Menstrual Cycle; Muscle, Skeletal; Muscles; Myalgia
PubMed: 33201156
DOI: 10.1519/JSC.0000000000003878 -
The Journal of Orthopaedic and Sports... Jun 2022To identify risk factors for quadriceps muscle strain injury in sport. (Review)
Review
OBJECTIVE
To identify risk factors for quadriceps muscle strain injury in sport.
DESIGN
Risk factor systematic review.
LITERATURE SEARCH
A systematic search was conducted in the MEDLINECINAHL, Embase, AMED, AUSPORT, SPORTDiscus, PEDro, and Cochrane Library databases (from inception to September 2021).
STUDY SELECTION CRITERIA
Studies reporting prospective data to evaluate risk factors related to index and/or recurrent quadriceps muscle strain injury.
DATA SYNTHESIS
A risk-of-bias assessment (using a modified Quality in Prognosis Studies tool) was performed, and we used best-evidence synthesis to qualitatively synthesize the data to quantify relationships between risk factors and quadriceps muscle injury.
RESULTS
Sixteen studies were included, capturing 2408 quadriceps injuries in 11 719 athletes. Meta-analyses were not performed due to clinical heterogeneity. The dominant kicking leg (over 3154 individuals, 1055 injuries), a previous history of quadriceps muscle injury (6208 individuals, 975 injuries), and a recent history of hamstring strain (4087 individuals, 581 injuries) were intrinsic factors associated with quadriceps injury. Extrinsic factors relating to the preseason period and competitive match play increased quadriceps injury risk; participating at higher levels of competition decreased quadriceps injury risk. Age, weight, and flexibility (intrinsic factors) had no association with quadriceps injury.
CONCLUSION
Previous quadriceps injury, recent hamstring injury, the dominant kicking leg, and competitive match play were the strongest risk factors for future quadriceps muscle injury in sport. .
Topics: Humans; Muscle, Skeletal; Prospective Studies; Quadriceps Muscle; Risk Factors; Sports
PubMed: 35647880
DOI: 10.2519/jospt.2022.10870