The purpose of this work was to provide a simple method to determine reactive strength during the 6-meter timed hop test (6mTH) and evaluate its association with isokinetic peak torque in patients following anterior cruciate ligament reconstruction (ACLR). Twenty-nine ACLR patients who were at least four months from surgery were included in this analysis. Participants were brought into the laboratory on one occasion to complete functional testing. Quadriceps and hamstring isokinetic testing was completed bilaterally at 60, 180, and 300 deg∙s-1, using extension peak torque from each speed as the outcome measure. The 6mTH was completed bilaterally using a marker-based motion capture system, and reactive strength ratio (RSR) was calculated from the vertical velocity of the pelvis during the test. An adjustment in RSR was made using the velocity of the 6mTH test to account for different strategies employed across participants. Repeated measures correlations were used to determine associations among isokinetic and hop testing variables. A two-way mixed analysis of variance was used to determine differences in isokinetic and hop testing variables between operated and non-operated legs and across male and female participants. Moderate positive associations were found between RSR (and adjusted RSR) and isokinetic peak torque at all speeds (r = .527 to .577). Mean comparisons showed significant main effects for leg and sex. Patients showed significant deficits in their operated versus non-operated legs in all isokinetic and hop testing variables, yet only isokinetic peak torque and timed hop time showed significant differences across male and female groups. Preliminary results are promising but further development is needed to validate other accessible technologies available to calculate reactive strength during functional testing after ACLR. Pending these developments, the effects of movement strategies, demographics, and levels of participation on RSR can then be explored to translate this simple method to clinical environments.

UNASSIGNED: The hamstring autograft can be harvested using various skin incisions, such as vertical, transverse, and oblique incisions, and from different localizations, including anteromedial and posteromedial harvest sites. The aim of this study was to compare studies on the anteromedial and posteromedial approaches for hamstring autograft harvest in terms of clinical outcomes, saphenous nerve injury, infection, operative time, graft length, incision length, range of motion, and patient satisfaction.
UNASSIGNED: Following the 2020 Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, a search was conducted in PubMed and Scopus, focusing on studies comparing anteromedial and posterior approaches for hamstring harvest. This study was registered with the PROSPERO International Prospective Register of Systematic Reviews (CRD42023450249). Methodological quality was evaluated using the Modified Coleman Methodology Score. Odds ratios (ORs) and mean differences (MDs) quantified dichotomous and continuous outcomes, respectively.
UNASSIGNED: Five articles, involving 405 knees, underwent analysis. Four studies were level 3 evidence, while 1 was level 1. The anteromedial hamstring harvest showed higher rates of saphenous nerve injury (OR, 9.77; 95% confidence interval [CI], 2.19-43.65; p = 0.003) and longer operative times, with an MD of about 13 minutes (MD, 13.33; 95% CI, 0.68-25.97; p = 0.04), compared to the posteromedial approach. The anteromedial method yielded a longer semitendinosus graft, with an MD of about 17 mm (MD, 17.57; 95% CI, 7.17-27.98; p = 0.0009). However, no significant differences existed in range of motion, flexion contracture, unintentional graft harvest, infection rates, and patient-reported outcomes. Notably, the posteromedial group reported higher cosmetic satisfaction, with 92% being very satisfied, compared to the anteromedial group with 80% (p = 0.005). However, overall satisfaction levels were similar between the 2 groups (p = 0.35), with a very satisfied rate of 72% for the anteromedial group and 78% for the posteromedial group.
UNASSIGNED: The anteromedial hamstring harvest showed greater saphenous nerve injury and longer operative times compared to the posteromedial approach, along with a longer graft. However, no significant differences were observed in the range of motion, flexion contracture, graft harvest, infection, or patient outcomes.

This study aimed to assess acute and residual changes in sprint-related hamstring injury (HSI) risk factors after a football (soccer) match, focusing on recovery within the commonly observed 72-h timeframe between elite football matches. We used a multifactorial approach within a football context, incorporating optical and ultrastructural microscopic analysis of BFlh (biceps femoris long head) muscle fibres, along with an examination of BFlh fibre composition. Changes in sprint performance-related factors and HSI modifiable risk factors were examined until 3 days after the match (MD +3) in 20 football players. BFlh biopsy specimens were obtained before and at MD +3 in 10 players. The findings indicated that at MD +3, sprint-related performance and HSI risk factors had not fully recovered, with notable increases in localized BFlh fibre disruptions. Interestingly, match load (both external and internal) did not correlate with changes in sprint performance or HSI risk factors nor with BFlh fibre disruption. Furthermore, our study revealed a balanced distribution of ATPase-based fibre types in BFlh, with type-II fibres associated with sprint performance. Overall, the results suggest that a 72-h recovery period may not be adequate for hamstring muscles in terms of both HSI risk factors and BFlh fibre structure following a football match.

Participants will be recruited from the Faculty of Physical Education and randomly assigned to either the hamstring stretching group or the control group with education only. The primary outcome measures will be pain intensity, musculoskeletal discomfort, and functional disability. Secondary outcome measures will be satisfaction with the intervention and flexibility of the hamstring. A total of 44 participants fulfilling the inclusion criteria will complete the study. As an increase in LBP frequency is observed, it seems justified to determine effective interventions for LBP and musculoskeletal discomfort in young people. The findings of this study will provide information about the effect of an 8-week intervention involving active hamstring flexibility exercises with hip flexion mobilization on the reduction of LBP and musculoskeletal discomfort during prolonged sitting in young adults. We hope this study will add to the development of ergonomic recommendations for young people with LBP.

暂无摘要。

BACKGROUND: The incidence and recurrence rate of hamstring strain injuries remain persistently high, with recurrent injuries leading to increased time lost during play and extended recovery periods compared with initial injury. Ultrasound imaging assesses important factors such as hamstring fascicle length (FL), pennation angle (PA), cross-sectional area (CSA), muscle thickness (MT), echo intensity (EI), and shear wave elastography (SWE), all impacting athletic performance. However, its reliability must be established before employing any measurement tool in research or clinical settings.
OBJECTIVE: To determine the reliability and measurement error of ultrasound for assessing hamstring FL, PA, CSA, MT, EI, and SWE among healthy adults and athletes; to synthesize the information regarding the operationalization of ultrasound.
METHODS: A systematic literature search was done from January 1990 to February 5, 2023, to identify reliability and validity studies of hamstring ultrasound assessment published in peer-reviewed journals with identifiable methodology of outcome measures.
RESULTS: Intraclass correlation coefficient measurement of 14 included studies reported moderate to excellent intrarater, interrater, and test-retest reliabilities of FL, PA, and MT regardless of the site of muscle testing, probe size, and setting, state of muscle, and use of different techniques in the extrapolation of FL. Good to excellent test-retest reliability rates for all hamstring anatomic CSA along midmuscle and different percentages of thigh length using panoramic imaging. Good intrarater reliability of EI regardless of gender and orientation of the probe but with excellent intrarater reliability in transverse scan using maximum region of interest. Good intrarater, interrater, and interday repeatability on SWE with the muscle in a stretched position.
CONCLUSIONS: Evidence from studies with a predominantly low risk of bias shows that ultrasound is a reliable tool to measure hamstring FL, PA, CSA, MT, EI, and SWE in healthy adults and athletes under various experimental conditions.

Hamstring strain injuries (HSI) are a common occurrence in athletics and complicated by high rates of reinjury. Evidence of remaining injury observed on magnetic resonance imaging (MRI) at the time of return to sport (RTS) may be associated with strength deficits and prognostic for reinjury, however, conventional imaging has failed to establish a relationship. Quantitative measure of muscle microstructure using diffusion tensor imaging (DTI) may hold potential for assessing a possible association between injury-related structural changes and clinical outcomes. The purpose of this study was to determine the association of RTS MRI-based quantitative measures, such as edema volume, muscle volume, and DTI metrics, with clinical outcomes (i.e., strength and reinjury) following HSI. Spearman\'s correlations and Firth logistic regressions were used to determine relationships in between-limb imaging measures and between-limb eccentric strength and reinjury status, respectively. Twenty injuries were observed, with four reinjuries. At the time of RTS, between-limb differences in eccentric hamstring strength were significantly associated with principal effective diffusivity eigenvalue λ1 (r = -0.64, p = 0.003) and marginally associated with mean diffusivity (r = -0.46, p = 0.056). Significant relationships between other MRI-based measures of morphology and eccentric strength were not detected, as well as between any MRI-based measure and reinjury status. In conclusion, this preliminary evidence indicates DTI may track differences in hamstring muscle microstructure, not captured by conventional imaging at the whole muscle level, that relate to eccentric strength.

BACKGROUND: Operative treatment is widely used for acute proximal hamstring avulsions, but its effectiveness compared with that of nonoperative treatment has not been shown in randomized trials.
METHODS: In this noninferiority trial at 10 centers in Sweden and Norway, we enrolled patients 30 to 70 years of age with a proximal hamstring avulsion in a randomized trial and a parallel observational cohort. Treatments were operative reinsertion of the tendons or nonoperative management. The primary end point was the Perth Hamstring Assessment Tool (PHAT) at 2 years of follow-up. Secondary outcomes included scores on the Lower Extremity Functional Scale (LEFS).
RESULTS: A total of 119 patients were enrolled in the randomized trial and 97 patients in the observational cohort. In the per-protocol analysis of the randomized trial, the mean (±standard deviation) PHAT scores were 79.9±19.5 and 78.5±19.4 in the operative and nonoperative groups, respectively (PHAT scores range from 0 to 100, with higher scores indicating higher function). The prespecified noninferiority limit of 10 points was not crossed (mean difference, -1.2; 95% confidence interval [CI], -8.6 to 6.2; P=0.009 for noninferiority). Analyses of secondary outcomes, including a mean difference in the LEFS score of -1.6 (95% CI, -5.2 to 2.0), aligned with the primary outcome. The observed numbers of adverse events in the randomized trial were nine in the operative group versus three in the nonoperative group (odds ratio, 0.3; 95% CI, 0.1 to 1.2). In the analysis of the observational cohort, the mean PHAT score difference between the nonoperative and operative treatment groups was -2.6 (95% CI, -9.9 to 4.6).
CONCLUSIONS: In patients 30 to 70 years of age with proximal hamstring avulsions, nonoperative treatment was noninferior to operative treatment. (Funded by Afa Försäkring and others; ClinicalTrials.gov number, NCT03311997.).

Cerebral palsy (CP) describes some upper motoneuron disorders due to non-progressive disturbances occurring in the developing brain that cause progressive changes to muscle. While longer sarcomeres increase muscle stiffness in patients with CP compared to typically developing (TD) patients, changes in extracellular matrix (ECM) architecture can increase stiffness. Our goal was to investigate how changes in muscle and ECM architecture impact muscle stiffness, gait and joint function in CP. Gracilis and adductor longus biopsies were collected from children with CP undergoing tendon lengthening surgery for hamstring and hip adduction contractures, respectively. Gracilis biopsies were collected from TD patients undergoing anterior cruciate ligament reconstruction surgery with hamstring autograft. Muscle mechanical testing, two-photon imaging and hydroxyproline assay were performed on biopsies. Corresponding data were compared to radiographic hip displacement in CP adductors (CPA), gait kinematics in CP hamstrings (CPH), and joint range of motion in CPA and CPH. We found at matched sarcomere lengths muscle stiffness and collagen architecture were similar between TD and CP hamstrings. However, CPH stiffness (R2 = 0.1973), collagen content (R2 = 0.5099) and cross-linking (R2 = 0.3233) were correlated to decreased knee range of motion. Additionally, we observed collagen fibres within the muscle ECM increase alignment during muscular stretching. These data demonstrate that while ECM architecture is similar between TD and CP hamstrings, collagen fibres biomechanics are sensitive to muscle strain and may be altered at longer in vivo sarcomere lengths in CP muscle. Future studies could evaluate the impact of ECM architecture on TD and CP muscle stiffness across in vivo operating ranges. KEY POINTS: At matched sarcomere lengths, gracilis muscle mechanics and collagen architecture are similar in TD patients and patients with CP. In both TD and CP muscles, collagen fibres dynamically increase their alignment during muscle stretching. Aspects of muscle mechanics and collagen architecture are predictive of in vivo knee joint motion and radiographic hip displacement in patients with CP. Longer sarcomere lengths in CP muscle in vivo may alter collagen architecture and biomechanics to drive deficits in joint mobility and gait function.

Anterior cruciate ligament reconstruction (ACLR) is one of the most common orthopedic procedures, and huge variation exists in the surgical technique. Single bundle hamstrings autograft reconstruction is a common method and has good clinical outcomes. A criticism of the hamstrings autograft is a small graft diameter, often less than 8-mm, which has been associated with increased re-rupture rates. Several graft preparation techniques for single bundle hamstrings autograft exist. Perioperative decisions include the number of tendons utilized, number of graft strands, graft configuration, and femoral and tibial fixation methods. Awareness of the minimum tendon and graft length required to produce each graft variation is necessary to avoid common pitfalls. However, intraoperative graft modification is possible to maximize graft diameter, and obtain proper fixation. The objective of this current concepts review is to describe the indications, surgical anatomy, technique, intraoperative tips, clinical outcomes, and complications for single bundle hamstrings autograft preparation techniques in ACLR.