Peak torque angle, acceleration time and time to peak torque as additional parameters extracted from isokinetic test in professional soccer players: a cross-sectional study.

This study investigated additional and traditional variables from isokinetic test of thigh muscles in soccer players across different field positions. One hundred and eighty-nine athletes performed maximal concentric isokinetic knee contractions on dominant (DL) and non-dominant limb (NDL) at 60º/s and 240º/s. The additional outcomes peak torque angle (AngPT), acceleration time (AcT) and time to peak torque (TPT) and traditional outcomes Peak torque (PT), total work (TW) and power (Pw) were extracted from the exam. Goalkeepers (GK), side backs (SB), central backs (CB), central defender midfielders (CDM), central attacking midfielders (CAM) and forwards (FW) were considered. Comparisons between limbs and positions demonstrated that SB extensors of the DL presented TPT lower (p = 0.006) and AngPT higher (p = 0.011) than NDL at 60°/s. CDM extensors of the DL showed lower TPT at 60°/s (p = 0.003) and 240°/s (p = 0.024). CAM flexors of the DL showed lower TPT (p = 0.026) and AcT (p = 0.021) at 240°/s than NDL. CB, CDM and CAM extensors of the NDL showed higher PT, TW and Pw than DL (p < 0.05). In conclusion, there are muscle imbalances between limbs in SB, CDM and CAM and across different field positions.

Low-Load Blood-Flow Restriction Exercise to Failure and Nonfailure and Myoelectric Activity: A Meta-Analysis.

OBJECTIVE: To compare the short- and long-term effects of low-load resistance training with blood-flow restriction (LL-BFR) versus low- (LL-RT) or high- (HL-RT) load resistance training with free blood flow on myoelectric activity and investigate the differences between failure (exercise performed to volitional failure) and nonfailure (exercise not performed to volitional failure) protocols. DATA SOURCES: We identified sources by searching the MEDLINE, PubMed, CINAHL, Web of Science, CENTRAL, Scopus, SPORTDiscus, and PEDro electronic databases. STUDY SELECTION: We screened the titles and abstracts of 1048 articles using our inclusion criteria. A total of 39 articles were selected for further analysis. DATA EXTRACTION: Two reviewers independently assessed the methodologic quality of each study and extracted the data. A meta-analytic approach was used to compute standardized mean differences (SMDs) ± 95% CIs. Subgroup analyses were conducted for both failure and nonfailure protocols. DATA SYNTHESIS: The search identified 39 articles that met the inclusion criteria. Regarding the short-term effects, LL-BFR increased muscle excitability compared with LL-RT during nonfailure protocols (SMD = 0.61; 95% CI = 0.34, 0.88), whereas HL-RT increased muscle excitability compared with LL-BFR during failure (SMD = -0.61; 95% CI = -1.01, -0.21) and nonfailure (SMD = -1.13; 95% CI = -1.94, -0.33) protocols. Concerning the long-term effects, LL-BFR increased muscle excitability compared with LL-RT during exercises performed to failure (SMD = 1.09; 95% CI = 0.39, 1.79). CONCLUSIONS: Greater short-term muscle excitability levels were observed in LL-BFR than in LL-RT during nonfailure protocols. Conversely, greater muscle excitability was present during HL-RT than LL-BFR, regardless of volitional failure. Furthermore, LL-BFR performed to failure increased muscle excitability in the long term compared with LL-RT.

Can Skin Temperature Be Altered After Different Magnitudes of Eccentric Exercise-Induced Muscle Damage?

Purpose: This study aimed to assess skin temperature (Tsk) changes after different magnitudes of exercise-induced muscle damage (EIMD) of the elbow flexor muscles and investigate whether Tsk is related to indirect markers of EIMD. Methods: Thirty healthy active men were randomly allocated to the mild (MiDG) (n = 15) or moderate (MoDG) (n = 15) muscle damage group. Muscle damage in elbow flexor muscles was induced by 10 (for MiDG) or 30 (for MoDG) maximal eccentric isokinetic contractions at 60 degrees/s. Tsk, maximal voluntary isometric contraction (MVIC), delayed-onset muscle soreness (DOMS), plasma creatine kinase (CK) activity, range of motion (ROM), and pressure pain threshold (PPT) were measured before and up to 72 hr after EIMD. Results: Tsk increased only immediately after EIMD (p < .05; f = 1.44) in the MoDG (4.2%) and MiDG (4.6%), returning to near baseline values 30 min after EIMD and remaining so thereafter. In addition, there was no intergroup difference (p > .05) at any of the times analyzed, or correlation between Tsk and most indirect markers of EIMD. Conclusions: In conclusion, Tsk should not be considered an indirect marker of mild or moderate muscle damage in active men, since alterations in this variable last less than 30 min after damaging exercise and showed no correlation with most indirect markers of EIMD.

Rate of torque development of paretic lower limb is an excellent predictor of walking speed in chronic stroke individuals.

BACKGROUND: Walking speed discriminates levels of functionality in stroke survivors, but its relationship with neuromuscular parameters remains unclear. We aimed to (1) verify relationships between walking speed, peak torque, and rate of torque development in individuals with chronic stroke and (2) investigate whether adjusting the predictive model for assistive device use and lower limb motor function improves its accuracy. METHODS: Twenty-nine stroke survivors (time post-stroke ≥6 months) were assessed for walking speed, motor function, torque of knee extensors, and rate of torque development. Hierarchical multiple regression was conducted to infer the contribution of assistive device use and lower limb motor function in the proportion of variance in walking speed explained by neuromuscular parameters. Adequacy of regression models was verified using Shapiro-Wilk test and visual inspection of histograms. FINDINGS: Rate of torque development measures presented higher coefficients of determination (R2 = 0.399-0.457) than peak torque (R2 = 0.333). However, no differences were observed between correlation coefficients (P > 0.05). When adjusted for assistive device use and lower limb motor function, coefficients of determination of all neuromuscular parameters were improved (P < 0.05). Regression models showed good adequacy. INTERPRETATION: Peak torque and rate of torque development from knee extensors are adequate predictors of walking speed in stroke survivors. Adjusting predictive models for assistive device use and lower limb motor function increases predictive capacity. These findings may have repercussions for assessing chronic stroke individuals and developing treatment strategies.

Repetition Failure Occurs Earlier During Low-Load Resistance Exercise With High But Not Low Blood Flow Restriction Pressures: A Systematic Review and Meta-analysis.

ABSTRACT: Cerqueira, MS, Lira, M, Mendonça Barboza, JA, Burr, JF, Wanderley e Lima, TB, Maciel, DG, and De Brito Vieira, WH. Repetition failure occurs earlier during low-load resistance exercise with high but not low blood flow restriction pressures: a systematic review and meta-analysis. J Strength Cond Res XX(X): 000-000, 2021-High-load and low-load resistance training (LL-RT) performed to failure are considered effective for improving muscle mass and strength. Alternatively, LL-RT with blood flow restriction (LL-BFR) may accelerate repetition failure and has been suggested to be more time efficient than LL-RT. This study explores the evidence for the effects of LL-BFR vs. LL-RT on repetition failure. A systematic literature search was conducted in the PubMed, CINAHL, Web of Science, CENTRAL, Scopus, SPORTDiscus, and PEDro databases. Meta-analyses of mean differences and 95% confidence intervals (CIs) were performed using a random-effects model. Subgroup analyses were conducted for both the high and low blood flow restriction pressures. The search identified n = 10 articles that met the inclusion criteria. The meta-analysis comprised a total of 218 healthy subjects. Low-load resistance training with blood flow restriction with high pressures (≥50% arterial occlusion pressure [AOP]) precipitate repetition failure in ∼14.5 fewer repetitions (95% CI -19.53 to -9.38) compared with LL-RT, whereas the use of low pressures (<50% AOP) stimulated repetition failure with ∼1.4 fewer repetitions (95% CI -3.11 to 0.37); however, this difference was not statistically significant. Repetition failure has been demonstrated to be an important normalizing variable when comparing the hypertrophic and strength effects resulting from resistance training and occurs earlier during low-load resistance exercise with high but not low blood flow restriction pressures.

Effects of transcranial direct current stimulation associated or combined with exercise on musculoskeletal pain: systematic review / Efeitos da estimulação transcraniana por corrente contínua associada ou combinada ao exercício na dor musculoesquelética: revisão sistemática

ABSTRACT BACKGROUND AND OBJECTIVES: Aerobic/resistance exercises and transcranial direct current stimulation (tDCS) can produce analgesic effects in patients with musculoskeletal pain, however, the summed effect of these two therapeutic resources remains unclear. The present study aimed to verify the effects of tDCS associated or combined with aerobic/resistance exercise on musculoskeletal pain. CONTENTS: The search was carried out in the databases: Pubmed, LILACS, Scielo. The intervention considered was tDCS associated or combined with exercises and the comparison was exercise without tDCS or with sham tDCS. Randomized controlled trials enrolling patients with musculoskeletal pain were included. There were no restrictions on the language and year of publication and the methodological quality was verified with PEDro Scale. Three trials were included with a total of 110 participants. The methodological quality was high, with an average of 9 points on the PEDro Scale. The studies used tDCS in the primary motor cortex with an intensity of 1 or 2 mA, for 20 minutes. The participants included were aged between 18 and 75 years and had the following diseases: fibromyalgia, osteoarthritis or chronic low back pain. CONCLUSION: Overall, tDCS did not overcome the sham tDCS to enhance the effects of exercise in reducing musculoskeletal pain.

RESUMO JUSTIFICATIVA E OBJETIVOS: Os exercícios aeróbios/resistidos e a estimulação transcraniana por corrente contínua (ETCC) podem produzir efeitos analgésicos em pacientes com dores de origem musculoesquelética, porém, o efeito somado destes dois recursos terapêuticos ainda não está claro. O objetivo do presente estudo foi verificar os efeitos da ETCC associada ou combinada ao exercício aeróbio/resistido na dor musculoesquelética. CONTEÚDO: A busca foi realizada nas bases de dados Pubmed, LILACS e Scielo. A intervenção considerada foi ETCC associada ou combinada a exercícios e a comparação foi exercício sem ETCC ou com ETCC simulada. Foram incluídos ensaios clínicos randomizados envolvendo pacientes com dor musculoesquelética aguda ou crônica. Não houve restrições quanto ao idioma e ano de publicação e a qualidade metodológica dos estudos foi verificada por meio da escala PEDro. Três ensaios foram incluídos com um total de 110 participantes. A qualidade metodológica foi alta, com uma média de 9 pontos na escala PEDro. Os estudos utilizaram a ETCC no córtex motor primário com intensidade de 1 ou 2 mA, por 20min. Os participantes tinham idade entre 18 e 75 anos e eram portadores de fibromialgia, osteoartrite ou lombalgia crônica. CONCLUSÃO: A ETCC não superou a ETCC simulada para potencializar os efeitos do exercício na redução de dor musculoesquelética.

Effect of Pain Education, Cryotherapy, and Transcutaneous Electrical Nerve Stimulation on the Pain, Functional Capacity, and Quality of Life in Patients With Nonspecific Chronic Low Back Pain: A Single-Blind Randomized Controlled Trial.

OBJECTIVE: The aim of the study was to analyze the effects of pain education and the combined use of cryotherapy and transcutaneous electrical nerve stimulation on the pain sensation, functional capacity, and quality of life of patients with nonspecific chronic low back pain. DESIGN: This is a randomized controlled and blind clinical trial including patients with nonspecific chronic low back pain in the following 4 groups: control group, cryotherapy group, burst transcutaneous electrical nerve stimulation group, and cryotherapy combined with burst transcutaneous electrical nerve stimulation group. They were evaluated at baseline and after the protocol was concluded using the following: Roland-Morris questionnaire and sit-to-stand test; quality-of-life questionnaire; and pain. The protocol consisted of 10 sessions with pain education associated the combination of the electrophysical agents. RESULTS: There were no statistical differences between groups after the intervention protocol. In the within analysis, all groups presented an improvement in visual analog scale scores, Roland-Morris questionnaire, sit-to-stand test, and pain domain of quality-of-life questionnaire. CONCLUSIONS: This study showed that with pain education, there was no difference between cryotherapy and transcutaneous electrical nerve stimulation alone, combined, or placebo mode in improving pain, functional capacity, and quality of life in patients with nonspecific chronic low back pain.

Effects of blood flow restriction without additional exercise on strength reductions and muscular atrophy following immobilization: A systematic review.

Purpose: To investigate whether blood flow restriction (BFR) without concomitant exercise mitigated strength reduction and atrophy of thigh muscles in subjects under immobilization for lower limbs. Methods: The following databases were searched: PubMed, CINAHL, PEDro, Web of Science, Central, and Scopus. Results: The search identified 3 eligible studies, and the total sample in the identified studies consisted of 38 participants. Isokinetic and isometric torque of the knee flexors and extensors was examined in 2 studies. Cross-sectional area of thigh muscles was evaluated in 1 study, and thigh girth was measured in 2 studies. The BFR protocol was 5 sets of 5 min of occlusion and 3 min of free flow, twice daily for approximately 2 weeks. As a whole, the included studies indicate that BFR without exercise is able to minimize strength reduction and muscular atrophy after immobilization. It is crucial to emphasize, however, that the included studies showed a high risk of bias, especially regarding allocation concealment, blinding of outcome assessment, intention-to-treat analyses, and group similarity at baseline. Conclusion: Although potentially useful, the high risk of bias presented by original studies limits the indication of BFR without concomitant exercise as an effective countermeasure against strength reduction and atrophy mediated by immobilization.