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.

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.

Skin temperature of middle distance runners after a maximum effort test

The purposeof this study was to analyze skin temperature(Tsk)responses after a short-term maximum effort test in middle-distance runners.Aquasi-experimental study was conducted with ten men (age 23.5±5.10 years)who trained 5 days per week, 2 to 3 hours per day,and were submitted to thermographic evaluationbefore and after Cooper's 12-minute run test (CRT). The mean temperature of the anterior-superior,posterior-superior,anterior-inferior,and posterior-inferiorregionswas compared between the sides(i.e., left and right)before and after CRT.The paired t-testshowed asignificantdecrease in Tskafter CRT in thefollowingregions:right pectoralis major (-3.4%), left pectoralis major (-3.4%),and abdomen (-5%) in the anterior-superior view (p<0.01); and in the upper right trunk (-1.9%),upper lefttrunk(-1.9%) and lower back (-2.9%) in the posterior-superior view (p<0.05). In the lower limbs,asignificantincreaseintemperature of the left knee (1.6%),and right (3.6%) and left ankles (2.9%) in the anteriorview (p<0.05),as well as in theright (4.3%) and left ankles (3.7%) in the posteriorview (p<0.05)wereobserved. There was no difference in temperature between the right and left sides. In conclusion, the Tskchange of middle-distance runners wassymmetricalbetween sides,decreasing in upper limbs and trunk and increasing in lower limbs after a short-term maximum effort test.