Objective To determine the effects of an eccentric hamstrings strength-training program, performed for at least 4 weeks by healthy adults, on muscle architecture and eccentric strength. Data Sources A systematic search was performed up to October 2018 in the following electronic databases: PubMed, PEDro, CINAHL and SPORTDiscus. Combinations of the following search terms were used: eccentric strength training, eccentric loading, nordic hamstring, hamstring strength, fascicle length, pennation angle, muscle thickness, muscle architecture, biceps femoris long head, biceps femoris, and hamstring muscles. Study Selection Included articles were randomized controlled trials that allowed comparisons between isolated eccentric strength training of the biceps femoris muscle and other programs. Data Extraction Data from the included studies were extracted by 2 independent reviewers. These data included the study design, participant characteristics, inclusion and exclusion criteria of clinical studies, exercise and intervention characteristics, outcome measures, and the main results of the study. When meta-analysis was possible, we performed quantitative analysis. Ten randomized controlled trials were included. Data Synthesis Limited to moderate evidence indicated that eccentric strength training was associated with an increase in fascicle length (mean difference [MD] = 1.97; 95% confidence interval [CI] = 1.48, 2.46), an increase in muscle thickness (MD = 0.10; 95% CI = 0.06, 0.13), and a decrease in pennation angle (MD = 2.36; 95% CI = 1.61, 3.11). Conflicted to moderate evidence indicated that eccentric hamstrings strength was increased after eccentric strength training compared with concentric strength training (standardized mean difference [SMD] = 1.06; 95% CI = 0.26, 1.86), usual level of activity (SMD = 2.72; 95% CI = 1.68, 3.77), and static stretching (SMD = 0.39; 95% CI = −0.97, 1.75). Conclusions In healthy adults, an eccentric strength-training program produced architectural adaptations on the long head of the biceps femoris muscle and increased eccentric hamstrings strength.

OBJECTIVE: The purpose of this systematic review with meta-analysis was to compare the effects of low load resistance combined with blood flow restriction (BFR) versus conventional quadriceps strengthening on knee symptoms and function as well as knee extensor strength and muscle thickness in adults with knee conditions. LITERATURE SURVEY: Guidelines based on the latest evidence highlight the importance of quadriceps strengthening to reduce pain and improve function in patients with knee conditions. Blood flow restriction is based on brief periods of vascular occlusion which cause muscle hypertrophy and increased strength. Before it can be recommended for individuals with knee conditions, quadriceps strengthening with low load resistance combined with BFR (LL-BFR) must show beneficial effects on clinical outcomes in addition to quadriceps strength and mass. METHODS: A systematic review with meta-analysis was conducted to identify relevant studies through PubMed, PEDro, and ScienceDirect up to January 2019. The protocol was registered on PROSPERO (CRD42019121306). Differences in pre-and post-intervention means and standard deviations were extracted to calculate the standardized mean difference for each intervention in each included study. SYNTHESIS: Eight studies were included. Limited evidence suggests that LL-BFR is more beneficial on quadriceps strength and thickness in patients with knee conditions than LL training alone or in addition to a rehabilitation program. Limited evidence indicates that LL-BFR training is equally effective in improving function and muscle thickness compared with a HL quadriceps strengthening program but elicits less knee pain, corresponding to additional benefits of 22 (95% confidence interval 1 to 43) mm on a 0-100 mm visual analogue scale. CONCLUSIONS: BFR could be a useful option for patients with knee conditions where conventional quadriceps strengthening program exacerbate knee symptoms. Future investigations should compare different BFR protocols to help establish better guidelines for clinicians.

Context Rotator cuff weakness and rotation ratio imbalances are possible risk factors for shoulder injury among overhead athletes. In consensus statements, organizations have highlighted the importance of a screening examination to identify athletes at risk of injury. The screening should be portable and designed to be feasible in many different environments and contexts. Objective To evaluate the reliability and validity of the Self-Assessment Corner (SAC) for self-assessing shoulder isometric rotational strength and examining whether performance on 2 physical performance tests was correlated with isometric shoulder rotational strength using the SAC in handball players. Design Cross-sectional study. Setting Sport setting. Patients or Other Participants A first sample of 42 participants (18 men, 24 women) was recruited to determine the reliability and validity of the SAC. In a second sample of 34 handball players (18 men, 16 women), we examined correlations between physical performance tests and the SAC. Main Outcome Measure(s) The SAC was used to measure isometric rotational strength with the upper extremity at 90° of abduction in the frontal plane and 90° of external rotation and the elbow flexed to 90° with neutral rotation of the forearm. The SAC findings were compared with those from manual testing. Results from the seated medicine ball throw (SMBT) and closed kinetic chain upper extremity stability test (CKCUEST) were used to establish relationships with the SAC. We calculated intraclass correlation coefficients to determine relative reliability and used standard error of measurement and minimal detectable change to quantify absolute reliability. Relationships among the different strength-testing procedures and with the physical performance tests were determined using the Pearson product moment correlation coefficient (r) or Spearman rank correlation coefficient (rs). Results We observed good to excellent reliability (intraclass correlation coefficient [2,k] range = 0.89 to 0.92). The standard error of measurement varied from 3.45 to 3.48 N. The minimal detectable change with 95% confidence intervals ranged from 8.06 to 8.13 N. Strong correlations were present among strength procedures (r = 0.824, rs range = 0.754–0.816). We observed moderate to strong correlations between the CKCUEST findings and rotational strength (r range = 0.570–0.767). Moderate correlations were found between rotational strength and SMBT (r range = 0.573–0.626). Conclusions The SAC is a clinically applicable and standardized protocol for self-assessing rotational strength in young healthy adults without pathologic conditions. Performance on the SMBT and CKCUEST may be valuable as a screening tool to further assess shoulder strength.

Females with PFP exhibited diminished hip abductor, trunk extensor and ankle plantar flexor endurance compared to healthy controls.

Objectives: The primary purpose was to evaluate the reliability of the Upper Limb Rotation Test (ULRT). The secondary objective was to evaluate the relationship between the ULRT and two PPTs (SMBT and CKCUEST), trunk rotation range of motion (SRT) and shoulder rotational isometric strength. Design: Reliability study and correlation study. Setting: Laboratory. Participants: 91 healthy adults participated to establish the reliability and validity of the ULRT. Main outcome measures: We used a two-session measurement design to evaluate the reliability of the ULRT. The SMBT, CKCUEST, SAC and the SRT were performed to determine relationships with the ULRT. Results: Results showed good reliability. The SEM 95 and the MDC 95 showed clinically acceptable absolute reliability values for the ULRT. A moderate correlation was found between the ULRT and CKCUEST scores. A moderate correlation was found between ULRT and SMBT scores. Conclusions: Results demonstrated good relative reliability and clinically acceptable absolute reliability values for the ULRT. Performances on the ULRT were moderately correlated with the PPTs.