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Purpose: Performing back squats with elastic bands has been widely used in resistance training. Although research demonstrated greater training effects obtained from adding elastic bands to the back squat, little is known regarding the optimal elastic resistance and how it affects neuromuscular performance. This study aimed to compare the force, velocity, power, and muscle activity during back squats with different contributions of elastic resistance. Methods: Thirteen basketball players performed 3 repetitions of the back squat at 85% of 1-repetition maximum across 4 conditions: (1) total load from free weight and (2) 20%, (3) 30%, and (4) 40% of the total load from elastic band and the remaining load from free weight. The eccentric and concentric phases of the back squat were divided into upper, middle, and bottom phases. Results: In the eccentric phase, mean velocity progressively increased with increasing elastic resistance, and muscle activity of the vastus medialis and rectus femoris significantly increased with the largest elastic resistance in the upper phase (P ≤.036). In the concentric phase, mean power (P ≤.021) and rate of force development (P ≤.002) significantly increased with increasing elastic resistance. Furthermore, muscle activity of the vastus lateralis and vastus medialis significantly improved with the largest elastic resistance in the upper phases (P ≤.021). Conclusion: Velocity, power, rate of force development, and selective muscle activity increased as the elastic resistance increased in different phases during the back-squat exercise. [ABSTRACT FROM AUTHOR]

Context: 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. Objectives: 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. Evidence Acquisition: 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. Evidence Synthesis: 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. Conclusion: 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. [ABSTRACT FROM AUTHOR]

Context: The persistence and the recurrence of posterior medial knee pain (PKP) after anterior cruciate ligament reconstruction (ACLR) using hamstring tendon graft are often overlooked during rehabilitation. Design: Cross-sectional observational study. Methods: The study aimed (1) to evaluate the prevalence of these types of PKP before 4 months post-ACLR, (2) to measure their consequences on the knee flexors strength, and (3) to evaluate the role of the type of ACLR. From a cohort of patients operated on with hamstring tendon procedures, the persistent and the recurrent PKP were sought at 4 months post-ACLR. The evolution of isokinetic muscle strength recovery in PKP subjects was compared with those of nonpainful subjects. The functional deficit was measured at 6/7 months post-ACLR by a hop test. Results: Three hundred seventeen subjects (25.8 [6.0] y) were included. At 4 months post-ACLR, 2 populations were identified based on the recurrent onset of PKP (PKP+, n = 40) or the absence of knee pain (PKP−, n = 277). The prevalence of PKP was 8.3%. At the fourth month post-ACLR, the PKP+ group had a higher flexor strength deficit compared with the PKP− group (limb symmetry index at 60°/s: 67.2% [12.4%] vs 84.3% [12.6%]; P <.05). At 6/7 months, the loss of strength persisted (limb symmetry index at 60°/s: 82.3% [13.4%] vs 87.7% [12.8%]; P <.05). The hop test deficit was comparable, and no difference was shown according to the type of graft. Conclusions: Persistent and recurrent PKP during the rehabilitation period were not uncommon and were associated with a worsening of flexors strength loss on the ACLR side. [ABSTRACT FROM AUTHOR]

Disruptions in gait function are common after concussion in adolescents; however, the neuromotor control deficits driving these gait disruptions are not well known. Fifteen concussed (age mean [SD]): 17.4 [0.6], 13 females, days since injury: 26.3 [9.9]) and 17 uninjured (age: 18.0 [0.7], 10 females) adolescents completed 3 trials each of single-task gait and dual-task gait (DT). During DT, participants simultaneously walked while completing a serial subtraction task. Gait metrics and variability in instantaneous mean frequency in lower extremity muscles were captured by inertial sensors and surface electromyography, respectively. A 2-way analysis of covariance was used to compare gait metrics across groups and conditions. Functional principal components analysis was used to identify regions of variability in instantaneous mean frequency curves. Functional principal component scores were compared across groups using a Welch statistic. Both groups displayed worse performance on gait metrics during DT condition compared to single-task, with no differences between groups (P <.001). Concussed adolescents displayed significantly greater instantaneous mean frequency, indicated by functional principal component 1, in the tibialis anterior, biceps femoris, and semitendinosus (P <.05) during single-task and DT compared with uninjured adolescents. Our observations suggest that concussed adolescents display inefficient motor unit recruitment lasting longer than 2 weeks following injury, regardless of the addition of a secondary task. [ABSTRACT FROM AUTHOR]

The hamstring plays an important role in reducing loads born by the anterior cruciate ligament. As anterior cruciate ligament injuries occur rapidly after ground contact, how the hamstring is activated prior to landing can influence injury risk. The purpose was to determine sex-related differences in hamstring activation immediately before landing and the effect of fatigue on "preactivation." Twenty-four participants (13 males and 11 females, age = 24.3 [6.5] y, mass = 72.2 [19.3] kg, height = 169 [9.7] cm) participated in this study. Participants completed a drop-vertical jump protocol before and after a lower body fatigue protocol. Hamstring electromyography (EMG) amplitude at 5 periods prior to landing, peak vertical ground reactions forces (in newtons/body weight), rate of loading (in body weight/second), and landing error scoring system were measured. Females had higher EMG amplitude before and after fatigue (P <.024), with decreased EMG amplitude for both sexes after fatigue (P =.025). There was no change on vertical ground reaction force, rate of loading, or landing error scoring system. Males and females demonstrated similar landing performance before and after fatigue but have different hamstring neuromuscular coordination strategies. The acute reduction in hamstring EMG amplitude following fatigue may increase loading on the anterior cruciate ligament. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study implemented the Copenhagen Adductor Exercise (CAE) and Nordic Hamstring Exercise (NHE) to examine 1) whether CAE and NHE interventions are associated with adductor and hamstring strength gains in youth African male soccer players and 2) whether strength changes after a rest period and secondary intervention. STUDY DESIGN: Pre-post intervention study. METHODS: Forty-four African elite male academy players (age 14.7±1.5 [12-18] years) participated in twice weekly CAE and NHE interventions for 8- and 10-week periods separated by a 4-week rest. Long lever adductor squeeze strength and prone isometric hamstring strength were measured with mixed-effects linear regression models to observe strength changes over time. RESULTS: Ninety-six and 95% of CAE and NHE sessions were completed in each intervention, with no adverse events related to the execution of the exercises. Adductor squeeze strength increased during the first intervention (baseline 3.23 [2.99-3.47] N/kg, post-intervention 3.53 [3.30-3.76] N/kg, p=0.911) and was maintained following the rest period (3.52 [3.27-3.76] N/kg, p=0.999) and second intervention (3.60 [3.35-3.84] N/kg, p=0.002). Hamstring strength improved during the first intervention (baseline 4.95 [4.42-5.49] N/kg, post-intervention 5.48 [4.95-6.02] N/kg, p<0.001), decreased to baseline during the rest period (4.98 [4.44-5.53] N/kg, p=0.996), and did not improve during the second intervention (5.01 [4.46-5.55] N/kg, p=0.978). CONCLUSION: CAE and NHE interventions can be implemented at an elite African academy with high compliance. Adductor and hamstring strength improved in the first intervention, with no further improvements in the second intervention. Secondary interventions therefore should include higher exercise volume or load to improve longitudinal adductor and hamstring strength. Level of Evidence: Level III (Cohort Study) [ABSTRACT FROM AUTHOR]

Background: There have been emerging clinical trials investigating the efficacy of synthetic-graft-augmented autografts in anterior cruciate ligament reconstruction (ACLR) in recent years. Hamstring tendon and Ligament Augmentation and Reconstruction System (LARS) are both widely discussed graft choices for ACLR. Purpose: To compare the clinical efficacy of hamstring tendon grafts with LARS-augmented hamstring tendon grafts in ACLR. Study Design: Systematic review and meta-analysis. Method: A systematic literature search was performed in PubMed, Embase and the Cochrane Library to identify primary evidence related to the comparison of ACLR with a hamstring tendon (HT) versus a hamstring tendon with LARS (HT + LARS). Quality assessment of the included studies was conducted using Newcastle–Ottawa Scale for non-RCTs. Quantitative analysis was conducted with Reviewer Manager 5.4. The primary outcomes compared were the Lysholm scale, Tegnar activity scale, International Knee Documentation Committee (IKDC) evaluation, KT-1000-based laxity, complication/retear rate and rate of return-to-sports. The secondary outcomes were the Knee Injury and Osteoarthritis Outcomes Score (KOOS), Global Rating of Change (GRC) scale, hop tests, isokinetic knee strength tests and radiographic and arthroscopic evaluations. Results: Six cohort studies with 710 participants were included in this study. Compared with the HT group, the HT + LARS group had better Lysholm scores at the 1-year follow-up (P = 0.0007) and at the final follow-up (P = 0.04). HT + LARS group had better IKDC scores at the 1-year follow-up (P = 0.003). The HT + LARS group had a better return-to-sports rate in short term. No significant difference in complications or re-surgery was observed. The secondary results revealed superior or non-inferior outcomes in the HT + LARS group. Conclusions: As grafts for ACLR, the use of hamstring tendons with LARS augmentation, compared with the use of hamstring tendons alone, in the short term, has significantly superior overall functional results and better early sports participation and non-inferior results in other comparisons. In the long term, the use of hamstring tendon with LARS augmentation demonstrated non-inferior results in terms of functional scores, knee stability, knee strength, complications and re-tear rate, etc. [ABSTRACT FROM AUTHOR]

Magnetic resonance imaging (MRI) is the gold standard for measuring muscle size. However, postural conditions for thigh musculature have not been standardized across studies, with some employing supine or prone positions and the thigh either placed on the examination table or suspended to avoid contact. In either case, the thigh is compressed or sagged by gravity, potentially affecting muscle size. This study aimed to examine the effects of postural conditions on thigh muscle size. Twenty Olympic‐style weightlifters and 20 untrained controls (10 men and 10 women in each group) underwent 3‐Tesla MRI in the supine and prone positions, with the thigh in compressed and suspended conditions to determine the maximal anatomical cross‐sectional area (ACSAmax) and muscle volume of 15 thigh muscle groups/individual muscles. Postural conditions changed the ACSAmax of the quadriceps (range of postural‐related changes: 1.0%–7.9%), hamstrings (0.8%–19.1%), and adductors (2.4%–19.2%). Regardless of measurement position, the total volume of thigh muscles decreased under compressed conditions (0.6%–3.8%). Quadriceps and adductors decreased in muscle volume under compressed conditions (0.9%–4.0% and 0.8%–6.6%), while hamstrings increased (1.4%–9.3%). Male weightlifters, who possessed the largest thigh muscle volume, showed greater postural‐related changes in the muscle volume of quadriceps, hamstrings, and adductors than the other subgroups. Therefore, postural conditions during MRI substantially change thigh muscle size, and the magnitude of the change depends on muscle size. Our results provide in vivo evidence of the compressive behavior of thigh muscles and a new technical perspective for assessing thigh muscle size. [ABSTRACT FROM AUTHOR]

Although the landing phases of the single-leg hop for distance (SLHD) are commonly assessed, limited work reflects how the take-off phase influences hop performance in patients with anterior cruciate ligament reconstruction (ACLR). To compare trunk and lower extremity biomechanics between individuals with ACLR and matched uninjured controls during take-off of the SLHD. Cross-sectional study design. Laboratory setting. Sixteen individuals with ACLR and 18 uninjured controls. Normalized quadriceps isokinetic torque, hop distance, and respective limb symmetry indices were collected for each participant. Sagittal and frontal kinematics and kinetics of the trunk, hip, knee, and ankle as well as vertical and horizontal ground reaction forces were recorded for loading and propulsion of the take-off phase of the SLHD. Those with ACLR had weaker quadriceps peak torque in the involved limb (P =.001) and greater strength asymmetry (P <.001) than control individuals. Normalized hop distance was not statistically different between limbs or between groups (P >.05), and hop distance symmetry was not different between groups (P >.05). During loading, the involved limb demonstrated lesser knee flexion angles (P =.030) and knee power (P =.007) than the uninvolved limb and lesser knee extension moments than the uninvolved limb (P =.001) and controls (P =.005). During propulsion, the involved limb demonstrated lesser knee extension moment (P =.027), knee power (P =.010), knee (P =.032) and ankle work (P =.032), and anterior-posterior ground reaction forces (P =.047) and greater knee (P =.016) abduction excursions than the uninvolved limb. Between-limb differences in SLHD take-off suggest a knee underloading strategy in the involved limb. These results provide further evidence that distance covered during SLHD assessment can overestimate function and fail to identify compensatory biomechanical strategies. [ABSTRACT FROM AUTHOR]

This study retrospectively compared the effect of holding the 2022 FIFA World Cup™ (WC) mid-season (season 2022/23) on injury rates and patterns in French Ligue 1 soccer clubs. Epidemiological data in 17 clubs were prospectively recorded by their physicians. Time-loss injuries (injuries leading to a player being unable to fully participate in play over the following 72-hour period) were compared with those reported during a regular season (2021–22). In the WC season, an increase of approximately 23% (training + match-play) was observed for both the total number of injuries and knee, ankle and muscle injuries combined. Incidences for match-play injury overall and for the knee, ankle and muscle regions combined and the hamstrings and calf regions specifically also rose significantly (range: p < 0.05-p < 0.01). These results suggest that injury occurrence and patterns in French L1 soccer clubs were substantially affected during the 2022/23 season when a mid-season WC was held. [ABSTRACT FROM AUTHOR]

Acute effects of static stretching (SS) and proprioceptive neuromuscular facilitation (PNF) on local and non-local range of motion (ROM) were assessed in 29 participants. Three evaluations were performed one week apart: week-1 Control session (CS); weeks 2–3 either SS or PNF interventions (randomized). Dominant and non-dominant limbs, local (hamstring extensibility) and non-local ROMs (Shoulder extension-ShE) were collected at baseline (T0), immediately after (T1), and fifteen minutes post-intervention (T2). No differences were found between time-points during the CS. Local-ROM significantly increased (p=0.0002, ES=0.74 and 0.0079, 0.56, for dominant and non-dominant lower limbs, respectively) after both SS and PNF. No interaction between time and treatment was detected for ShE in both limbs. However, post-hoc analysis revealed a significant increase in dominant upper limb ShE between T0 and T1 only after SS (p=0.002; +6.5%). Acute bouts of SS and PNF can increase local-ROM, however, no clear effects were observed for non-local ROM. [ABSTRACT FROM AUTHOR]

Isokinetic knee tests mostly evaluate reciprocal concentric-concentric flexor-extensor movements in a seated position. Discrete tests generate higher moments, but time requirements impede their widespread implementation. This study examined if hip angle (flexed vs. extended) and test modality (discrete vs. reciprocal) affect camera-based data (100 fps). Sixteen healthy males performed concentric (con) and eccentric (ecc) isokinetic knee flexor (H) and extensor (Q) movements (60°/s). Peak moments and contractional work of discrete and reciprocal tests (QconQecc, HconHecc) strongly correlated for extended (Q:91%≥R2≥71%; H:95%≥R2≥87%) and flexed hip (Q:88%≥R2≥70%; H:81%≥R2≥75%) without significant differences (p>0.05) between test modalities. Discrete and "traditional" seated QconHcon-tests revealed substantially lower correlations for extended (Q:44%≥R2≥43%; H:55%≥R2≥54%) and flexed hip (Q:81%≥R2≥77%; H:48%≥R2≥47%). Although most mean values did not significantly differ, moderate correlations were predominant and the respective limits of agreement demonstrated considerable effects of hip angle and test modality. These insights assist practitioners in interpreting isokinetic data of different test procedures. If time constraints prevent discrete knee tests (gold standard), concentric-eccentric movements provide highly correlated outcomes, independent of the hip angle. [ABSTRACT FROM AUTHOR]

Background/Objectives: Hamstring shortening is a significant musculoskeletal condition affecting the posture and mobility of the spine and lower extremities. This study examined the impact of incorporating neurodynamic slump stretch and suboccipital muscle inhibition into passive static stretching on hamstring flexibility in individuals with short hamstrings. Methods: 117 female participants were classified into three groups: the control group, which received passive static stretch of the hamstring muscle; the neurodynamic slump group, which received neurodynamic slump stretch with passive static stretch; and the suboccipital muscle inhibition group, which received suboccipital muscle inhibition with passive static stretch, for three sessions a week, 10 min each, for four weeks. The outcome measures were the popliteal angle test (PAT), straight leg raising (SLR) test, and forward bending test (FBT) at baseline, immediately following the first session and after four weeks. Results: Statistically significant differences were found within groups (p < 0.001) for all outcome measures. Between the groups, there was a more significant improvement in the PAT and the SLR tests, favoring the neurodynamic slump and suboccipital muscle inhibition groups in comparison with the passive static stretch group (p < 0.001) with no significant difference between the two groups after the first session and at four weeks of treatment. However, the FBT showed no significant differences immediately following the first session or at four weeks of treatment (p > 0.05). Conclusions: This study found that incorporating neurodynamic slump stretch and suboccipital muscle inhibition into passive static stretch techniques effectively treats short hamstrings in healthy individuals. [ABSTRACT FROM AUTHOR]

Background: Knee osteoarthritis (KOA) is a common musculoskeletal disorder. Therapeutic ultrasound (US) is a safe and effective treatment for KOA. It relieves knee pain and enhances function. Metformin (MF) regulates chondrocytes, hence providing chondroprotection. Furthermore, it efficiently reduces knee articular cartilage degeneration and retards the progression of osteoarthritis. However, the localized administration of MF by phonophoresis for KOA has yet to be studied. Purpose: To assess the possible effects of metformin phonophoresis (MFPH) plus exercise therapy (EX) compared to MFPH alone or the US on knee pain, function, and range of motion (ROM) in chronic KOA patients. Methods: Seventy-eight patients with unilateral mild to moderate chronic KOA were included. Patients were randomly assigned to three groups: group A (MFPH + EX), group B (MFPH alone), and group C (US). The US group used an acoustic-neutral gel, while the MFPH group used a gel containing 1.2% MF. The exercises included hamstring stretches, calf stretches, and knee strengthening exercises. Treatment in the three groups continued for four weeks (three sessions per week). The Visual Analog Scale (VAS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the goniometer were used to assess knee pain, function disability, and ROM, respectively. All measures were recorded before, 2 weeks, and 4 weeks after the intervention in all groups. Multivariate Analysis of Variance (MNOVA) was performed to compare the effects within and between groups for knee ROM and function disability. The Kruskal-Wallis test and the Friedman test analyzed the pain intensity. Results: When the baseline patient characteristics were compared, there were no significant differences in means of age, gender, body mass index (BMI), or lower limb dominance across the three groups (p > 0.05). After 4 weeks of intervention, clinical outcomes significantly improved in all three groups (p < 0.05). However, patients in the MFPH + EX group improved significantly in all outcomes compared to the MFPH and US groups (p < 0.05). Conclusion: Post-treatment results showed a statistically and clinically significant improvement in pain intensity, knee ROM, and function in the MFPH group; however, combining MFPH with exercises is more beneficial in reducing KOA symptoms. Trial registration: Clinical Trial Registry at (pactr.samrc.ac.za) database. NO: PACTR202311507335269. Date: November 9, 2023 (retrospectively registered). [ABSTRACT FROM AUTHOR]

Purpose: Hamstring spasticity is prevalent following neurological injury. The standardized assessment involves passive knee extension, in a position of 90° hip flexion. This creates passive insufficiency of the muscle and lacks ecological validity for walking, whereby the hip typically flexes to a maximum of 40° during swing phase, while the knee extends. This study compared assessment outcomes when completed in 40° and 90° hip flexion. Methods: The Modified Ashworth Scale and Modified Tardieu Scale, were performed on 35 adults with a neurological condition. Each participant was assessed by three assessors, resulting in 105 trials at 40° and 90°. Results: There was a significant increase in the proportion of trials rated as spastic using the Modified Ashworth Scale (p=.012, phi=.27), and Modified Tardieu Scale (p<.001, phi=.36), and the severity of spasticity using the Modified Ashworth Scale (p<.001, effect size (ES)=.50), and Modified Tardieu Scale (p<.001 ES=.47), at 90° hip flexion. The angle of reaction occurred 32° earlier at 90° hip flexion (p<.001, ES = 1.61). Conclusions: Completing hamstring assessments in 40° hip flexion may reduce the passive insufficiency and improve the ecological validity of assessment, for walking. This may assist in the selection of patients requiring intervention, when their goal relates to walking. IMPLICATIONS FOR REHABILITATION: The position of the hip joint impacts hamstring spasticity assessment outcomes, regardless of the clinical outcome measure chosen The application of bedside assessment methods in a manner reflective of functional tasks may assist in selecting individuals who require active spasticity intervention As per international guidelines, the use of validated outcome measures in a goal directed and patient centered manner is required to maximize patient care [ABSTRACT FROM AUTHOR]

Background: Isokinetic normative data in females' soccer players is scarce in comparison to males. Furthermore, evaluation protocols employed to obtain those data in female's studies, strongly differ from each other, using different ranges of speeds and movement patterns, thus producing different output data. Thus, it is difficult for the researcher and the clinician to choose a correct protocol for knee isokinetic test in female soccer players. Aim of this paper is to review the literature to provide updated information on how to interpret a knee isokinetic testing in healthy females. Methods: Google Scholar, PubMed, Sport Discus, and Psych info databases were queried, and 17 papers were selected. Following PRISMA methodology and PEDro scale, we classified the retrieved papers and assessed the quality. Results: In this review some common features of isokinetic testing in female soccer players of various levels of qualification are highlighted. The isokinetic performance indexes widely accepted are the hamstring/quadriceps (H/Q) ratio and dominant/non-dominant (D/ND) ratio. It also emerges that, 3 reps at the speed of 60°/sec in knee flexion/extension are preferable due to the higher reliability and that the optimal H/Q ratio in healthy female soccer players of different level of qualification and age is 50%, while the interlimb differences (D/ND) should be below 10%. Conclusions: Normative data and methodologies reviewed can be useful for the isokinetic test of female soccer players. It emerges that simplifying test procedures limiting at few testing speed and considering selected H/Q and D/ND gives all the necessary relevant informations. [ABSTRACT FROM AUTHOR]

Background: Anterior instability of the sternoclavicular joint (SCJ) is a rare but potentially devastating pathological condition, particularly when it occurs in young or active patients. SCJ reconstruction using hamstring tendon autograft is a commonly used treatment option, yet to date results are limited to small case series. Studies on baseline, preoperative factors and their association with postoperative outcome are limited. Purpose: To assess the midterm clinical outcomes and survivorship after SCJ reconstruction using hamstring tendon autograft in patients experiencing anterior SCJ instability and to determine whether baseline patient or causative factors are associated with postoperative outcomes or patient satisfaction. Study Design: Case series; Level of evidence, 4. Methods: Patients who underwent SCJ reconstruction with a hamstring tendon autograft for anterior SCJ instability between October 2005 and October 2020 were included in this retrospective single-center study. At a minimum of 2 years postoperatively, clinical outcomes were collected, including the following patient-reported outcomes (PROs): the 12-Item Short Form Survey (SF-12) score; American Shoulder and Elbow Surgeons (ASES) score; Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score; Single Assessment Numeric Evaluation (SANE) score; and visual analog scale (VAS) pain score. Subjective postoperative satisfaction with the procedure was quantified on a scale from 0 (very unsatisfied) to 10 (very satisfied). The predictive role of patient factors, including age, sex, and injury in dominant arm, on postoperative PROs and satisfaction at short-term follow-up was evaluated using multiple linear regression. Results: A total of 49 patients (mean age, 29.6 ± 16.2 years; range 13.8-67.1 years; 27 females) were included in the final analysis. At a mean follow-up of 3.9 ± 2.1 years, all PROs had significantly improved, including the mean SF-12 Physical Component Summary score (40.4 ± 6.8 to 52.6 ± 6.9; P <.001), ASES score (54.9 ± 20.4 to 91.0 ± 11.3; P <.001), QuickDASH score (41.2 ± 18.5 to 10.2 ± 9.1; P <.001); SANE score (50.2 ± 21.1 to 88.3 ± 8.8; P <.001), VAS pain score (4.4 ± 2.6 to 0.8 ± 1.4; P <.001), and VAS pain score at its worst (7.4 ± 2.5 to 3.3 ± 2.6; P <.001). The median postoperative satisfaction score was 9 (range, 1-10). Revision-free survivorship was 95.9%. Male patients had a significantly lower VAS pain score at its worst compared with female patients (2.6 ± 2.6 vs 4.1 ± 2.4; P =.045); higher age was significantly correlated with a worse QuickDASH score (correlation coefficient, 0.314; P =.036). Overhead athletes had a significantly lower propensity to return to sport compared with nonoverhead athletes (P =.043), with only 45% of the overhead athletes returning to a level similar to their preinjury level, whereas 81% of the nonoverhead athletes were able to do so. Conclusion: The significant improvements in clinical and sport-specific outcomes and high patient satisfaction after SCJ reconstruction with a hamstring tendon autograft demonstrate the success of this procedure in treating anterior SCJ instability. Male sex and younger patient age are associated with superior outcomes, while overhead athletes have to be counseled about difficulties of returning to preinjury level of sport postoperatively. [ABSTRACT FROM AUTHOR]

This study compared lower extremity (LE) muscular strength by 3 groups of female athletes using chronological age and consideration of age of peak height velocity (PHV). Isometric quadriceps, hamstrings, and hip abductors strength were assessed from physically active, pediatric females. The body mass normalized isometric strength (N m/kg) was compared by the 3 age groups. There were 388 young female athletes (<10 years [14.2%], 11-14 years [48.7%], and 15-18 years [37.1%]). The body mass normalized LE strength was lower in 11-14 years compared with <10 years (quadriceps [ P =.001], hamstrings [ P =.001], and hip abductors [ P =.037]) as well as in 15-18 years relative to <10 years in quadriceps (P =.001) and hamstrings (P =.001). The analysis results were consistent with both chronological age alone and incorporating effects of age of PHV. In short, body mass normalized LE strength (quadriceps, hamstrings, and hip abductors) of 11-14 years females was lower than <10 years females. [ABSTRACT FROM AUTHOR]

Purpose: Proprioceptive neuromuscular facilitation (PNF) stretching is considered a clinically effective way to enhance muscle properties; however, rare information exists about its effect on muscle flexibility and strength of the patients with stroke. To investigate the efficacy of PNF exercise on lower extremity muscle flexibility and strength after stroke. Methods: Twenty-four... [ABSTRACT FROM AUTHOR]

Background: Biocomposite screws reportedly provide equivalent graft fixation in anterior cruciate ligament reconstruction (ACLR) to metallic screws while simplifying subsequent imaging and surgery. One purported complication of biocomposite screws is paradoxical tunnel widening. Previous studies on beta-tricalcium phosphate screws have only reported outcomes at short- and midterm follow-up. Purpose: To radiographically assess the tibial tunnel 10 years after ACLR using hamstring tendon autografts and biocomposite interference screws in anatomic single-bundle (SB) and double-bundle (DB) methods. Study Design: Case series; Level of evidence, 4. Methods: Of the 105 initially recruited patients, 61 (58%) completed all follow-up evaluations for inclusion in this long-term study. A total of 26 patients received anatomic SB ACLR and 35 patients received DB ACLR with biocomposite interference screws containing beta-tricalcium phosphate in the tibia. Weightbearing anteroposterior and lateral radiographs of the index knee were taken in the early postoperative period and at 2, 5, and 10 years postoperatively; computed tomography (CT) imaging was performed at 10-year follow-up. Subjective and objective clinical assessments were recorded preoperatively and at 10-year follow-up. Results: The mean follow-up period was 122 months. In 76% of radiographs in the SB group, the width of the tibial tunnel had not increased at 10 years compared with the early postoperative period. The mean tibial tunnel volume on CT in the SB group was 2.04 cm3 (± 0.85 cm3). In the DB group, the posterolateral tunnel width had not increased in 69% of radiographs; the same was found in 63% of radiographs for the anteromedial tunnel at 10-year follow-up. The mean posterolateral tunnel volume on CT was 2.04 cm3 (±1.92 cm3) and the mean anteromedial tunnel volume was 1.38 cm3 (±0.54 cm3). There was no correlation between tunnel widths and KT-1000 arthrometer assessments. There was a moderate but statistically significant correlation between SB tibial tunnel volume on CT imaging and KT-1000 arthrometer anterior 134 N side-to-side difference (r = 0.45; P =.039). Conclusion: Most patients' tibial tunnels had not increased on 1 or both radiographic views at 10-year follow-up compared with the early postoperative period after ACLR using biocomposite interference screws, with no obvious negative effect on outcomes. However, the tunnels were still visible in most patients at 10 years on standard radiographs and CT imaging. [ABSTRACT FROM AUTHOR]

Context: Anatomy trains theory states that performing techniques in any part of the superficial myofascial backline can remotely treat other parts of this pathway. Due to the connections of different parts of the superficial backline, it is possible to influence the hamstring by performing the technique in the lumbar area. As chronic nonspecific low back pain (LBP) may lead to or be caused by hamstring tightness, remote myofascial release (MFR) techniques using the superficial backline can help improve hamstring tightness. Objective: This study aimed to evaluate the effect of remote MFR on hamstring tightness for those with chronic nonspecific LBP. Design: Single-blind, parallel design. Setting: The present study was performed at the clinical setting of Tarbiat Modares University in Iran. Methods: This study included 40 participants (20 males and 20 females) who were 40.5 (5.3) years old with chronic nonspecific LBP and hamstring tightness. Interventions: Participants were randomly divided into the lumbar MFR (remote area) and hamstring MFR groups. Participants underwent 4 sessions of MFR for 2 weeks. Main Outcome Measures: A passive knee-extension (PKE) test was used for muscle tightness evaluation 3 times. Results: Repeated-measure analysis of variance test showed that after the lumbar and hamstring MFR, the PKE was significantly reduced in both legs: lumbar MFR (right knee: from 61.04° [2.17°] to 51.01° [4.11°], P ≤.003 and left knee: from 63.02° [3.12°] to 52.09° [2.48°], P ≤.004) and hamstring MFR (right knee: from 62.01° [4.32°] to 50.50° [7.18°], P ≤.001 and left knee: from 63.11° [2.56°] to 51.32° [5.31°], P ≤.002). Least Significant Difference (LSD) post hoc test results showed that the 2 groups were not significantly different after the MFR (P ≥.05). Also, the intraclass correlation coefficient index showed that the PKE test has excellent reliability (intraclass correlation coefficient,.910 for the right limb and.915 for the left limb). The minimal detectable change at the 95% confidence interval indicated that a change greater than or equal to 6° is required to exceed the threshold of the error PKE test, respectively. Conclusion: The present study showed that the remote MFR technique to the lumbar region demonstrated the same significant results in decreasing hamstring tightness as was noted in hamstring MFR to both limbs in patients with chronic nonspecific LBP. [ABSTRACT FROM AUTHOR]

Purpose: Muscle architecture is associated with motor performance and muscle injury. While muscle architecture and knee-flexor eccentric strength change with growth, the influence of anthropometric measures on these properties is rarely considered. This study aimed to investigate the relationship between hamstring muscle architecture and knee-flexor eccentric strength with anthropometric measurements. Methods: Sixty male footballers (16.6 [1.05] y) from the U16, U17, and U19 teams of an elite soccer club were included in this study. Fascicle length, pennation angle, and muscle thickness of the biceps femoris long head (BFlh) and semimembranosus muscles were measured in both legs using ultrasound. Knee-flexor eccentric strength, height, body mass, leg length, femur length, and peak height velocity (PHV) were measured within 1 week of the ultrasound images. A stepwise regression and 1-way analysis of variance tests were used to evaluate the effects of age, maturity, and anthropometric measurements on muscle properties. Results: Variance within BFlh and semimembranosus muscle thickness (r <.61), semimembranosus pennation angle (r <.58), and knee-flexor eccentric strength (r =.50) were highly related to body mass. We observed no significant correlations between muscle architecture and age (P >.29). However, moderately greater BFlh muscle thickness was shown for the post-PHV compared with the PHV group (effect size ± 90% CI: 0.72 ± 0.49). Conclusions: In conclusion, weak correlations between muscle architecture and anthropometric measurements suggest that other factors (ie, genetics, training regimen) influence muscle architecture. The moderate effect of maturity on BFlh muscle thickness strongly suggests post-PHV hypertrophy of the BFlh muscle. Our results confirmed previous findings that eccentric knee-flexor strength is influenced by body mass. [ABSTRACT FROM AUTHOR]

Anterior cruciate ligament injury prevention should focus primarily on reduction of the knee abduction moment (KAM) in landing tasks. Gluteus medius and hamstring forces are considered to decrease KAM during landing. The effects of different muscle stimulations on KAM reduction were compared using 2 electrode sizes (standard 38 cm2 and half size 19 cm2) during a landing task. Twelve young healthy female adults (22.3 [3.6] y, 1.62 [0.02] m, 50.2 [4.7] kg) were recruited. KAM was calculated under 3 conditions of muscle stimulation (gluteus medius, biceps femoris, and both gluteus medius, and biceps femoris) using 2 electrode sizes, respectively versus no stimulation during a landing task. A repeated-measures analysis of variance determined that KAM differed significantly among stimulation conditions and post hoc analysis revealed that KAM was significantly decreased in conditions of stimulating either the gluteus medius (P <.001) or the biceps femoris (P <.001) with the standard electrode size, and condition of stimulating both gluteus medius and biceps femoris with half-size electrode (P =.012) when compared with the control condition. Therefore, stimulation on the gluteus medius, the biceps femoris, or both muscles could be implemented for the examination of anterior cruciate ligament injury potential. [ABSTRACT FROM AUTHOR]

Background: Bone–patellar tendon–bone (BPTB) and double-looped semitendinosus and gracilis (hamstring) grafts are commonly used for anterior cruciate ligament (ACL) reconstruction. Short-term and midterm studies show little or no differences between the 2 grafts; however, there are only a few long-term studies to compare results between the 2 grafts. Purpose: To compare the results after using either BPTB grafts or hamstring tendon grafts 18 years after ACL reconstruction. Study Design: Randomized controlled trial; Level of evidence 2. Methods: A total of 114 patients with ACL rupture between 2001 and 2004 were randomized to reconstruction with either a BPTB graft or a hamstring tendon graft. Patients were operated on at 4 major hospitals. The 18-year follow-up evaluation included anterior knee laxity measured with a KT-1000 arthrometer, defined as the primary outcome, while clinical examination (Lachman and pivot-shift tests), isokinetic testing of muscle strength, patient-reported outcome measures, and an assessment of radiographic osteoarthritis using the Kellgren-Lawrence classification were defined as secondary outcomes. Results: A total of 96 patients (84%, 47 BPTB and 49 hamstring grafts) were available for follow-up, 71 of these for clinical examination. Seven of 96 patients were excluded for ACL revision (n = 5) or knee replacement (n = 2) surgery. In total, 25 patients (10 BPTB and 15 hamstring grafts) had undergone additional surgery other than ACL revision or total knee arthroplasty. There were no significant differences between the groups in terms of anterior laxity test with KT-1000 arthrometer (primary outcome). In secondary outcomes, no significant differences between groups were reported regarding clinical examination, patient-reported outcome scores, or radiographic osteoarthritis (Kellgren-Lawrence grade 2-4 for patellofemoral joint [18 hamstring and 14 BPTB] or tibiofemoral joint [20 hamstring and 19 BPTB]), while isokinetic testing revealed that the hamstring group had a 10.7% reduction in mean peak flexion torque compared with the BPTB group at 60 deg/s (df = 59; P =.011). At 60 deg/s the mean total flexion work in the hamstring group was reduced by 17.2% compared with the BPTB group (df = 59; P =.002). Conclusion: The flexion strength in the hamstring group was significantly reduced in the operated knee after 18 years. There were no significant differences between the groups regarding subjective outcomes, patient-reported outcomes, range of motion, clinical and instrumented knee laxity, and the development of osteoarthritis. Registration: NCT05876013 (ClinicalTrials.gov identifier). [ABSTRACT FROM AUTHOR]

Existing patellofemoral pain (PFP) literature has primarily been focused on quadriceps muscle volume, with limited attention given to the deep and superficial muscle volume of the lower limbs in individuals with unilateral and bilateral PFP. In this paper, we aim to fill this gap. To explore superficial and deep lower extremity muscle volume in women with unilateral or bilateral PFP compared with a normative database of pain-free women. Cross-sectional study. University imaging research center. Twenty women with PFP (10 unilateral and 10 bilateral) and 8 pain-free women from a normative database. We quantified lower extremity muscle volume via 3.0-T magnetic resonance imaging. Two separate 1-way analyses of variance were performed: (1) unilateral PFP (painful versus nonpainful limb) versus pain-free control groups and (2) bilateral PFP (more painful versus less painful limb) versus pain-free control groups. We observed no differences in age and body mass index across groups (P >.05). Compared with the pain-free group, the unilateral and bilateral PFP groups had bilaterally smaller volumes of the anterior (iliacus: P ≤.0004; d range, 2.12–2.65), medial (adductor brevis, adductor longus, gracilis, and pectineus: P ≤.02; d range, 1.25–2.48), posterior (obturator externus, obturator internus, and quadratus femoris: P <.05; d range, 1.17–4.82), and lateral (gluteus minimus: P ≤.03; d range, 1.16–2.09) hip muscles and knee extensors (rectus femoris: P ≤.003; d range, 1.67–2.16) and flexors (long and short head of the biceps femoris: P ≤.01, d range, 1.56–1.93). Women with unilateral and those with bilateral PFP displayed less volume of multiple superficial and deep muscles of the bilateral hips and knees than pain-free women. Interventions should bilaterally target lower limb muscles when treating PFP, and hypertrophy exercises for specific muscles should be explored to increase choices for intervention. [ABSTRACT FROM AUTHOR]

Targeted resistance training stimulates hamstring muscle hypertrophy, but its effect on tendon‐aponeurosis geometry is unknown. This study examined changes in hamstring muscle, free tendon, and aponeurosis geometry following a 10 week Nordic or hip extension exercise intervention. Thirty recreationally active males were randomly allocated (n = 10 per group) to a Nordic, hip extension, or control group. Magnetic resonance imaging of both thighs was acquired pre‐ and post‐intervention. Changes in free tendon and aponeurosis volume for each hamstring muscle, biceps femoris long head (BFlh) aponeurosis interface area and muscle volume‐to‐interface area ratio were compared between groups. Regional changes in muscle CSA were examined via statistical parametric mapping. The change in semimembranosus free tendon volume was greater for the Nordic than control group (mean difference = 0.06 cm3, 95% CI = 0.02–0.11 cm3). No significant between‐group differences existed for other hamstring free tendons or aponeuroses. There were no between‐group differences in change in BFlh interface area. Change in BFlh muscle volume‐to‐interface area ratio was greater in the hip extension than Nordic (mean difference = 0.10, 95% CI = 0.007–0.19, p = 0.03) and control (mean difference = 0.12, 95% CI = 0.03–0.22, p = 0.009) groups. Change in muscle CSA following training was greatest in the mid‐portion of semitendinosus for both intervention groups, and the mid‐portion of BFlh for the hip extension group. There was limited evidence for tendon‐aponeurosis hypertrophy after 10 weeks of training with the Nordic or hip extension exercises. For the BFlh, neither intervention altered the interface area although hip extension training stimulated an increase in the muscle volume‐to‐interface area ratio, which may have implications for localized tissue strains. Alternative muscle‐tendon loading strategies appear necessary to stimulate hamstring tendon adaptations. [ABSTRACT FROM AUTHOR]

Objective: Identify key flexibility and point-of-care musculoskeletal ultrasound (POCUS) measures for prognosticating return-toplay (RTP) following a first hamstring strain injury (HSI) and informing the clinical decision-making process. Design: Exploratory prospective cohort study. Setting: Sport medicine and rehabilitation clinic of a Canadian university. Participants: One hundred and sixty-seven elite Canadian university football athletes followed over 5 seasons. Interventions: Clinical and POCUS measures collected within 7 days after HSI and preseason clinical measures. MainOutcomeMeasures: Active knee extension (AKE) and Straight Leg Raise (SLR) to quantify hamstring flexibility, POCUS-related outcomes to characterize tissue alteration, and RTP until full sport resumption were documented (categorized as Early [1-40 days] or Late [.40 days] RTP). Results: A total of 19 and 14 athletes were included in the Early RTP (mean RTP 5 28.84 6 8.62 days) and Late RTP groups (mean 51.93 6 10.54 days), respectively, after having been diagnosed with a first HSI. For the clinical results, height and a greater flexibility asymmetry measure with the AKE or SLR when compared with both ipsilateral preseason and acute contralateral values significantly increases the chance of facing a long delay before returning to play (ie, RTP). For the POCUS-related results, the Peetrons severity score, extent of the longitudinal fibrillary alteration, and novel score lead to similar results. Conclusions: Early hamstring flexibility asymmetry following acute HSI, particularly the AKE, along with some POCUS-related measures are valuable in prognosticating late RTP following among Canadian university football athletes. [ABSTRACT FROM AUTHOR]

The aim was to present a descriptive 10-season summary of injury data from all teams of a professional football club using a heat map approach. Injuries and exposure time were registered according to the FIFA consensus in all men's and women's teams from Athletic Club over 10 seasons. A team-by-injury table was created, showing the incidence, median severity, and burden in each cell. Cells were coloured based on the injury burden value using a green – yellow–red gradient (lowest to highest). The highest overall injury burden was found in the women's 2nd and 1st teams and the men's U(under)17 team (>200 days lost/1000 h). Muscle injury burden demonstrated an increasing pattern with age. Knee joint/ligament injuries, particularly anterior cruciate ligament ruptures, had the highest impact on women's teams, followed by the men's 2nd team. In comparison, ankle joint/ligament injuries had a relatively low injury burden in most teams. Growth-related injuries were the most impactful injuries in the men's U15 and younger teams, and the women's U14 team. In conclusion, epidemiological data on injuries can inform and guide injury management processes. New and improved visualization methods might be important assets when presenting injury data to key decision-makers. [ABSTRACT FROM AUTHOR]

Background: Making a diagnosis of proximal hamstring tendinopathy (PHT) may be challenging, as patients with correlating clinical symptoms may have normal or minimal findings on magnetic resonance imaging (MRI) scans. Purpose/Hypothesis: The purpose of this study was to assess the effect of a novel hip flexion (HF) scanning position on the MRI diagnosis of PHT. It was hypothesized that the HF position, which simulates the symptom-provoking sitting position, would reveal PHT pathology more accurately than the standard scanning position. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: Patients with chronic PHT symptoms were included. Chronicity was defined as symptoms that were present for >3 months. Each patient underwent an MRI in 2 parts: (1) the standard pelvic examination in the supine position and (2) the novel HF position in which the patient lays on his or her side with the hip at 90° of flexion. Tendon insertion areas of the semimembranosus and the biceps femoris were analyzed independently by 2 experienced musculoskeletal radiologists, and the findings were classified as normal, tendinosis, or rupture. The MRI findings for both the standard and HF positions were compared in every patient, and the percentage of different diagnoses between the 2 MRI positions was reported. Results: In total, 38 patients (67 tendons) were analyzed. In 71% of the patients, the HF position revealed more severe injury than the standard position. The HF position showed a rupture in 16% of the tendons, with findings classified as tendinosis in the standard position. Of the tendons diagnosed as normal in the standard position, 6% were classified as rupture and 11% as tendinosis in the HF position. Conclusion: The novel HF scanning position offered additional value in the diagnosis of PHT in symptomatic patients when compared with the standard hip-in-neutral position. This position can improve the diagnostics of PHT, especially if an athlete or an active patient with gluteal area pain has normal or minimal MRI findings in the standard position. [ABSTRACT FROM AUTHOR]

The management of proximal hamstring tear (PHT) is debated and consensus regarding recommended measures and individual treatment regimens is lacking. The present investigation evaluated the efficacy of a conservative management of partial and complete PHT. The present observational study was conducted following the STROBE statement. In June 2018 the medical databases of the BG Klinikum Bergmannstrost Halle, Germany were accessed. All the patients with PHT were retrieved. The outcomes of interest were to evaluate the clinical examination, PROMs, imaging, and isokinetic muscle strength at the baseline and last follow-up. 31 patients were enrolled in the present study. Nine patients (29 % (9 of 31) described local pain at the ischial tuberosity in sitting situations and also in manual palpation. A persistent gap in the tendon string beneath the tuberosity in manual palpation was reported in 25.8 % (8 of 31). The mean VAS at the last follow-up was 2.3 ± 2.3. The mean LEFS score was 50.9 ± 18.8. Control MRI at follow-up showed scarring restitution in the proximal tendon in all patients in the partial tear group. In the complete tear group, a persisting defect state of the proximal tendon course was found in 45 % (9 of 20). The injured side achieved 81.5 ± 22.2 % of the force of the uninjured side, measured in the flexion movement at 60°/s. At an angular velocity of 240°/s, 83.2 ± 26.3 % of the force of the uninjured side was achieved. According to the main findings of the present study, conservative therapy of PTH tears is associated with good clinical outcomes. High-quality investigations are required to establish the proper therapeutic algorithm and advantages of conservative management compared to a surgical approach. Level III. • The management of proximal hamstring tear is debated and consensus regarding recommended measures and individual treatment regimens is lacking. • Conservative therapy of proximal hamstring tear tears is associated with good clinical outcomes. • High-quality investigations are required to establish the proper therapeutic algorithm and advantages of conservative management. [ABSTRACT FROM AUTHOR]

Background: The potential influence of a preoperative anterolateral ligament (ALL) lesion seen on magnetic resonance imaging (MRI) on the mid- and long-term surgical outcomes of anterior cruciate ligament (ACL) reconstruction is still controversial. Purpose: To evaluate the clinical outcomes and failure rate of isolated ACL reconstruction at a minimum 5-year follow-up in patients with and without ALL injury diagnosed preoperatively using MRI. Study Design: Cohort study; Level of evidence, 2. Methods: A prospective cohort of patients with acute ACL injury was divided into 2 groups based on the presence (ALL injury group) or absence (control group) of ALL injury on preoperative MRI. This is a longer-term follow-up study of a previously published study that had a minimum 2-year follow-up. Both groups underwent anatomic isolated reconstruction of the ACL. The Lysholm and subjective International Knee Documentation Committee scores, KT-1000 arthrometer and pivot-shift tests, reconstruction failure rate, incidence of contralateral ACL injury, presence of associated meniscal injury, and presence of knee hyperextension were evaluated. The evaluation at the 5-year follow-up was also compared with the same patient's evaluation at 2 years of follow-up. Results: A total of 156 patients were evaluated. No significant differences were found between the groups in the preoperative evaluation. In the postoperative evaluation, patients in the ALL injury group had a higher reconstruction failure rate (14.3% vs 4.6% for the control group; P =.049) and worse clinical outcomes according to the Lysholm scores (85.0 ± 10.3 vs 92.3 ± 6.6; P <.00001). Although the pivot-shift test results were similar, anteroposterior translation using the KT-1000 arthrometer revealed worse results for the ALL injury group (2.8 ± 1.4 mm vs 1.9 ± 1.3 mm; P =.00018). Patients in the ALL injury group also had an increase in KT-1000 arthrometer values from 2 to 5 years (2.4 ± 1.6 vs 2.8 ± 1.4; P =.038). Patients in the control group had no differences in outcomes from 2 to 5 years of follow-up. Conclusion: Combined ACL and ALL injuries were associated with significantly less favorable outcomes than were isolated ACL injuries at a minimum follow-up of 5 years after isolated ACL reconstruction with hamstring autograft. Patients with concomitant ALL injury showed a higher failure rate and worse functional scores. Also, knee stability tended to slightly worsen from 2 to 5 years in cases of associated ALL injury. [ABSTRACT FROM AUTHOR]

Background: Preventing severe arthrogenic muscle inhibition (AMI) after knee injury is critical for better prognosis. The novel Sonnery-Cottet classification of AMI enables the evaluation of AMI severity but requires validation. This study aimed to investigate the electromyography (EMG) patterns of leg muscles in the examination position from the classification during isometric contraction to confirm its validity. We hypothesised that the AMI pattern, which is characterised by quadriceps inhibition and hamstring hypercontraction, would be detectable in the supine position during isometric contraction. Methods: Patients with meniscal or knee ligament injuries were enrolled between August 2023 and May 2024. Surface EMG was assessed during submaximal voluntary isometric contractions (sMVIC) at 0° extension in the supine position for the vastus medialis (VM) and vastus lateralis (VL) muscles and at 20° flexion in the prone position for the semitendinosus (ST) and biceps femoris (BF) muscles. Reference values for normalisation were obtained from the EMG activity during the gait of the uninjured leg. The Kruskal–Wallis test was used to compare the activation patterns of the muscle groups within the same leg, and the post-hoc tests were conducted using the Mann–Whitney U test and Bonferroni correction. Results: Electromyographic data of 40 patients with knee injuries were analyzed. During sMVIC, the extensor and flexor muscles of the injured leg showed distinct behaviours (P < 0.001), whereas the uninjured side did not (P = 0.144). In the injured leg, the VM differed significantly from the ST (P = 0.018), and the VL differed significantly from the ST and BF (P = 0.001 and P = 0.026, respectively). However, there were no statistically significant differences within the extensor muscle groups (VM and VL, P = 0.487) or flexor muscle groups (ST and BF, P = 0.377). Conclusion: AMI was detectable in the examination position suggested by the Sonnery-Cottet classification. The flexor and extensor muscles of the injured leg exhibited distinct activation behaviours, with inhibition predominantly occurring in the quadriceps muscles, whereas the hamstrings showed excitation. [ABSTRACT FROM AUTHOR]

[Purpose] The purpose of this study was to compare the effectiveness of the Structural Diagnosis and Management (SDM) approach with Myofascial Release (MFR) in improving plantar heel pain, ankle range of motion, and disability. [Subjects] Sixty-four subjects, aged 30–60 years, with a diagnosis of plantar heel pain, plantar fasciitis, or calcaneal spur by a physician according to ICD-10, were equally allocated to the MFR (n = 32) and SDM (n = 32) groups by hospital randomization and concealed allocation. [Methods] In this assessor-blinded randomized clinical trial, the control group performed MFR to the plantar surface of the foot, triceps surae, and deep posterior compartment calf muscles, while the experimental group performed a multimodal approach utilizing the SDM concept for 12 sessions over 4 weeks. Both groups also received strengthening exercises, ice compression, and ultrasound therapy. Pain, activity limitations and disability were assessed as primary outcomes using the Foot Function Index (FFI) and Range of motion (ROM) assessment of the ankle dorsiflexors and plantar flexors using a universal goniometer. Secondary outcomes were measured using the Foot Ankle Disability Index (FADI) and a 10-point manual muscle testing process for the ankle dorsiflexors and plantar flexors. [Results] Both MFR and SDM groups exhibited significant improvements from baseline in all outcome variables, including pain, activity level, disability, range of motion, and function after the 12-week intervention period (p <.05). The SDM group showed more improvements than MFR for FFI pain (p <.01), FFI activity (p <.01), FFI (p <.01) and FADI (p = <.01). [Conclusion] Both MFR and SDM approaches are effective in reducing pain, improving function, ankle range of motion, and reducing disability in plantar heel pain, however, the SDM approach may be a preferred treatment option. [ABSTRACT FROM AUTHOR]

Background: Patient-specific risk profiles of clinical failure after anterior cruciate ligament reconstruction (ACLR) are meaningful for preoperative surgical planning and postoperative rehabilitation guidance. Purpose: To create an ensemble algorithm machine learning (ML) model and ML-based web-based tool that can predict the patient-specific risk of clinical failure after ACLR. Study Design: Cohort study; Level of evidence, 3. Methods: Included were 432 patients (mean age, 26.8 ± 8.4 years; 74.1% male) who underwent anatomic double-bundle ACLR with hamstring tendon autograft between January 2010 and February 2019. The primary outcome was the probability of clinical failure at a minimum 2-year follow-up. The authors included 24 independent variables for feature selection and model development. The data set was split randomly into training sets (75%) and test sets (25%). Models were built using 4 ML algorithms: extreme gradient boosting, random forest, light gradient boosting machine, and adaptive boosting. In addition, a weighted-average voting (WAV) ensemble model was constructed using the ensemble-voting technique to predict clinical failure after ACLR. Concordance (area under the receiver operating characteristic curve [AUC]), calibration, and decision curve analysis were used to evaluate predictive performances of the 5 models. Results: Clinical failure occurred in 73 of the 432 patients (16.9%). The 8 most important predictors for clinical failure were follow-up period, high-grade preoperative knee laxity, time from injury to ACLR, participation in competitive sports, posterior tibial slope, graft diameter, age at surgery, and medial meniscus resection. The WAV ensemble algorithm achieved the best predictive performance based on concordance (AUC, 0.9139), calibration (calibration intercept, –0.1806; calibration slope, 1.2794; Brier score, 0.0888), and decision curve analysis (greatest net benefits) and was used to develop an web-based application to predict a patient's clinical failure risk of ACLR. Conclusion: The WAV ensemble algorithm was able to accurately predict patient-specific risk of clinical failure after ACLR. Clinicians and patients can use the web-based application during preoperative consultation to understand individual prediction outcomes. [ABSTRACT FROM AUTHOR]

Background: Bridge-enhanced anterior cruciate ligament restoration (BEAR) combines suture repair of the anterior cruciate ligament (ACL) with an extracellular matrix implant plus autologous blood to facilitate native ACL healing. Purpose/Hypothesis: The purpose of this study was to compare the 6-year follow-up outcomes of patients who underwent the BEAR procedure with those of a nonrandomized concurrent control group receiving autograft ACL reconstruction (ACLR) in the first-in-human safety study of the BEAR implant (BEAR I trial). Based on the 2-year results, it was hypothesized that isometric hamstring strength after the BEAR procedure would be greater than that after ACLR and that there would be no other differences in outcomes at 6 years. Study Design: Cohort study, Level of evidence, 2. Methods: Ten patients underwent BEAR and 10 received ACLR with a 4-stranded hamstring autograft. Outcomes assessed included the record of subsequent surgeries, the International Knee Documentation Committee (IKDC) Subjective Knee Score, IKDC physical examination grade, the Knee injury and Osteoarthritis Outcome Score, instrumented knee laxity, functional outcomes (ie, muscle strength assessments and hop testing), and qualitative magnetic resonance imaging assessment. Comparisons between treatments were based on computations of the mean differences and the associated 95% CIs. Results: One patient in the BEAR group and 3 patients in the ACLR group were lost to follow-up. In the period between 2 and 6 years, 1 patient in each group underwent revision surgery. There were no differences between groups at the 6-year follow-up in any of the outcome measures except for isometric hamstring strength, which was approximately equal to that of the contralateral knee in the BEAR group and <44% of that in the contralateral knee in the ACLR group (P <.01). Conclusion: This preliminary study suggests that the outcomes of BEAR and ACLR with a hamstring tendon graft may be similar at the 6-year follow-up and warrants investigation of the BEAR procedure in a larger cohort of patients. [ABSTRACT FROM AUTHOR]

Background: Understanding the factors related to patient-reported outcomes (PROs) after anterior cruciate ligament reconstruction (ACLR) can lead to more effective interventions. Purpose/Hypothesis: The purpose of this study was to identify factors associated with PRO scores after ACLR. It was hypothesized that concomitant meniscal treatment and postoperative range of motion (ROM) would be associated with early postoperative PRO scores and that postoperative physical findings would be associated with 2-year postoperative PRO scores. Study Design: Cohort study; Level of evidence, 2. Methods: We examined the data from the Tokyo Medical and Dental University Multicenter Arthroscopic Knee Surgery (TMDU MAKS) Study for patients who underwent primary ACLR with autologous hamstring tendon grafts; 1252 patients in the TMDU MAKS Study were eligible for inclusion. The International Knee Documentation Committee (IKDC) subjective score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Lysholm score of the patients at 3 months (n = 675), 1 year (n = 660), and 2 years (n = 375) postoperatively were assessed using multiple regression to evaluate the strength of the relationship between PRO scores and the following predictor variables: patient-specific factors, treatment-specific factors, and physical findings. Results: Improvement in all PROs significantly exceeded the minimal important change at 1 and 2 years postoperatively. Older age and female sex were predictive of lower PRO scores up to 2 years postoperatively. Concurrent meniscal treatment and limited range of knee motion were predictive of lower PRO scores at 3 months and 1 year postoperatively. A tighter knee (ie, less anterior translation) on the injured side compared with the contralateral knee was predictive of lower KOOS–Quality of Life and IKDC scores at 2 years postoperatively. At all 3 postoperative time points, greater side-to-side difference in knee ROM was predictive of lower PRO scores. Conclusion: Inferior PRO scores were associated with concomitant meniscal treatment and limited postoperative ROM until 1 year postoperatively and with older age and female sex up to 2 years postoperatively. PRO scores were associated with knee stability at all assessed time points. [ABSTRACT FROM AUTHOR]

Background: Adequate graft size and length are crucial factors in anterior cruciate ligament (ACL) reconstruction. Accurate identification of patients who may be at risk for an insufficient length or size of the hamstring tendon (HT) can aid surgeons in preoperative planning. Purpose: To evaluate whether magnetic resonance imaging (MRI) or ultrasound could more accurately predict the size of the semitendinosus tendon (ST) and gracilis tendon (GT) and to investigate the correlation between anthropometry, graft size, and imaging measurements to find a predictive formula. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Included in the study were 36 patients who underwent ACL reconstruction with HT autograft at our institution between July 2021 and May 2022. Anthropometric data and MRI and ultrasound measurements were collected preoperatively. The length and diameter of the HT were recorded intraoperatively. Correlations between anthropometry, graft size, and imaging measurements were analyzed. Linear regression analysis was performed to construct a prediction formula. Results: The intraoperative graft diameters of the ST and GT were weakly to moderately associated with their cross-sectional areas as measured by MRI and ultrasound. MRI and ultrasound interpreted 11.9% to 15.7% and 18.4% to 41.7% of the variation in the graft diameter of the HT, with an accuracy of 50.0% to 55.6% and 69.4% to 86.1%, respectively. The intraoperative lengths of the ST and GT were both associated with patient height and tendon lengths as measured by ultrasound. Additionally, intraoperative GT length was associated with patient weight. Four formulas combining relevant anthropometric parameters and imaging measurements were calculated from multilinear regression analysis, explaining up to 46.3% of the variance in the size of HT. Conclusion: Ultrasound and MRI alone showed limited ability to predict the graft diameter of the ST and GT, while ultrasound could more accurately predict the graft size than MRI. Among the different anthropometric variables, height was the most influential in predicting tendon length. [ABSTRACT FROM AUTHOR]

Background/Aim: Low back pain (LBP) is a highly prevalent pathology affecting more than half of our population. The lumbar region inherently possesses a complex structure; therefore, dozens of causes for the clinical presentation of acute/chronic pain are present. We focused on the impact of hamstring shortness on LBP in healthcare workers/professionals who need to keep medical records and perform invasive procedures while traveling overwhelming distances in relatively small workplaces. Methods: Our research was designed as a cross-sectional study and was conducted at Beykent University Hospital from March to April 2022. Sixty-two otherwise healthy healthcare workers/professionals aged 25-45 (both male and female) volunteered. Two equal groups with and without LBP were created. Oswestry disability index, Roland-Morris score, Quebec LBP questionnaire, Visual Analog Scale (VAS), active/passive knee extension, sit and reach, and forward bending tests were performed in each group. The collected data were statistically analyzed (confidence interval [CI]=20%; P<0.05). Results: Active/passive knee extension, sit and reach, and toe touch tests were significantly related to Roland-Morris, Quebec, and Oswestry Disability Index questionnaires; thus hamstring muscle shortness was significantly related to chronic low back pain (P<0.05). Short hamstring muscle length could accurately reflect the lower test scores obtained by the female participants. Conclusion: Hamstring muscle shortness could explain a significant proportion of low back pain in healthcare professionals. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to evaluate the long-term outcomes of saphenous nerve (SN) injuries from hamstring tendon harvesting during ACL reconstruction, focusing on clinical results and patient satisfaction after at least two years. Additionally, it investigates the incidence, recovery patterns, and impact of these injuries on functional outcomes, daily activities, and ACL re-rupture rates immediately post-surgery and at final follow-up. Materials and methods: A retrospective review was conducted on patients who had undergone ACL reconstruction with hamstring tendon grafts at a single institution between January 2015 and January 2020. The incidence of SN injuries was assessed immediately after surgery and at final follow-up. Additionally, the recovery rate and time were evaluated, and the impact of these injuries on functional outcomes was measured using the Lysholm Knee Score (LKS) and patient-reported effects on daily activities. Results: Of the 159 patients analyzed, iatrogenic SN injuries were initially observed in 87 (54.7%) patients post-ACLR. By the final follow-up, paresthesia had resolved in 36 (22.6%) patients within an average of 11.1 months. Persistent SN injuries were recorded in 51 (32.1%) patients, affecting various extents of the infrapatellar branch (IPBSN) and the sartorial branch (SBSN) of the saphenous nerve. Patients with persistent SN injuries experienced a significant impact on daily activities and had lower LKS scores compared to those without injuries or with recovered injuries. Furthermore, a higher re-rupture rate was associated with persistent SN injuries. Conclusions: The study finds that SN injuries during hamstring graft harvesting for ACL reconstruction are common, with a significant portion of patients experiencing persistent sensory deficits for at least two years postoperatively. These injuries are observed to adversely affect patient satisfaction and functional outcomes and to increase the re-rupture rate. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to determine physiological and metabolic responses to two different sprint interval exercises (SIE) matched for total sprint duration and sprint-rest ratio. Methods: After having measured peak oxygen uptake (...), 14 healthy males (27.1 ± 4.8 yr, 169.6 ± 6.0 cm, 64.5 ± 8.4 kg, ... 47.2 ± 7.7 mL⋅kg-1⋅min-1) performed four 10-s sprints with 80-s recovery (SIE10) and two 20-s sprints with 160-s recovery (SIE20) on different occasions in a counterbalanced crossover manner. Pulmonary ... and changes in tissue oxygenation index (ΔTOI) at vastus lateralis (VL) and rectus femoris (RF) were measured during the SIE. Furthermore, T2-weighted magnetic resonance imaging was taken immediately before and after the SIE to determine the activation levels of VL, RF, vastus medialis, vastus intermedius, adductor magnus, biceps femoris long head, semitendinosus, and semimembranosus at 50% of right thigh length. Results: In SIE10, increases in ... and ΔTOI at VL and RF plateaued after the second sprint, whereas session-averaged ΔTOI was greater in SIE20 than SIE10 in both muscles (VL: 20.9 ± 7.4 vs 14.2% ± 5.9%, RF: 22.8 ± 9.3 vs 12.9% ± 6.6%, P = 0.00). Although both SIE significantly increased T2 values in all eight muscles, those magnitudes were similar between the conditions (SIE10 vs SIE20: 5%-16% vs 8%-16%). Conclusions: This study showed blunted responses of whole-body (...) and peripheral (ΔTOI) oxidative responses with successive sprints (sprint 1 < sprints 2-4) in SIE10, suggesting that increasing sprint repetitions does not necessarily induce greater oxidative metabolism or stimulus. Moreover, greater peripheral oxygen extraction (ΔTOI) was achieved with SIE20, whereas %changes of T2 indicates that the thigh muscles were similarly activated between the SIE conditions. [ABSTRACT FROM AUTHOR]

As a complex movement, Tai Chi (TC) could be challenging for knee control, and the compensatory changes in TC biomechanics of knee pain patients are unknown. The Brush Knee and Twist Step (BKTS) is a typical TC movement that involves basic leg motion repeated in the whole TC. This pilot study examined electromyography and retro-reflective marker trajectory data to investigate neuromuscular control strategies of the lower extremity during BKTS in TC practitioners with and without knee pain. Twelve experienced TC practitioners with (n = 6) and without knee pain (n = 6) participated. Our results revealed that knee pain practitioners presented muscle imbalance in the vastus medialis-vastus lateralis and vastus lateralis-biceps femoris, and poor alignment of the knee with the toes in TC lunge. Additionally, they adaptively developed rigid coordination strategies, showing higher levels of lower limb muscle co-contraction and activity compared to controls. Training programs for TC practitioners with knee pain should be designed to modify both abnormal muscle synergy patterns and incorrect lunge during TC, which may improve exercise safety. [ABSTRACT FROM AUTHOR]

The musculotendon mechanics of the hamstrings during high-speed running are thought to relate to injury but have rarely been examined in the context of prospectively occurring injury. This prospective study describes the hamstring musculotendon mechanics of two elite rugby players who sustained hamstring injuries during on-field running. Athletes undertook biomechanical analyses of high-speed running during a Super Rugby pre-season, prior to sustaining hamstring injuries during the subsequent competition season. The biceps femoris long head muscle experienced the greatest strain of all hamstring muscles during the late swing phase. When expressed relative to force capacity, biceps femoris long head also experienced the greatest musculotendon forces of all hamstring muscles. Musculotendon strain and force may both be key mechanisms for hamstring injury during the late swing phase of running. [ABSTRACT FROM AUTHOR]

The Nordic Hamstring Exercise (NHE) effectively strengthens the knee flexors. Typically conducted without assistance, extended knee angles are not reached with sustained muscle activation in the presence of insufficient eccentric strength and/or fatigue. This might impair the desired neuromuscular adaptations and assessment accuracy. This study investigated kinetic and kinematic differences between assisted and unassisted NHEs (3 × 3 repetitions) performed by sixteen male sprinters (22 years, 181 cm, 76 kg). Kinetic (peak moment, impulse) and kinematic parameters (e.g., time under tension, range of motion to excessive downward acceleration (ROMDWA) were investigated. All analysed parameters significantly differed between assisted and unassisted NHEs (p ≤ 0.003; 0.635≤ ηp² ≤ 0.929) favouring assisted execution, except for peak moments and maximal hip flexion. Repetition 1 of assisted NHEs revealed 21% higher impulses rising to 82% during repetition 9. Equivalent interactions of mode and repetition became apparent for time under tension, ROMDWA, mean and fractional angular velocity. Unassisted NHEs elicited substantially greater inter-repetition fatigue (rep1 vs. rep9): +79% fractional angular velocity (d = 1.01), −41% impulse (d = 1.53), −31% ROMDWA (d = 0.99) and −29% time under tension (d = 1.45). Assisted NHEs ensured higher execution quality and lower between-participant variability by facilitating a controlled full-ROM movement. Three sets of 3 NHEs sufficed to induce substantial fatigue within and across sets. [ABSTRACT FROM AUTHOR]

The article informs about the differences in quadriceps and hamstrings activation during repeated hops among athletes who underwent ACL reconstruction, emphasizing the need for nuanced assessment methods to detect these differences and ensure proper rehabilitation. Topics include the challenges athletes face after ACL reconstruction, the use of surface electromyography (SEMG) for neuromuscular analysis, and the importance of timing and magnitude of muscle activation in rehabilitation protocols.

Introduction: Asymmetrical gait mechanics after anterior cruciate ligament reconstruction (ACLR) are associated with the development of post-traumatic knee osteoarthritis. Current measures of gait mechanics have focused on peak magnitudes of knee kinematics, kinetics, and joint contact forces; nonetheless, they have seldom considered the plantar pressure and muscular frequency content in individuals with ACLR and pronate feet (PF). The present study aimed to compare ACLR and PF with healthy controls during walking. Material & Methods: The present study was conducted based on a quasi-experimental and laboratory design. The sample of this study comprised 13 people with ACLR and PF and 13 subjects from the healthy group. The mean age scores of patients in the two groups of healthy and sick participants were 22.9±4.1 and 23.2±4.5 years, respectively. During the test, subjects walked barefoot on an 18-m runway. Peak plantar pressure variables in both groups were recorded by a foot scan system (sampling rate: 300 Hz). The electromyography activity of the tibialis anterior, gastrocnemius medialis, vastus lateralis, vastus medialis, rectus femoris, biceps femoris, semitendinosus, and gluteus medius were recorded during walking. Results:The results demonstrated that the peak midfoot region plantar pressure values (P=0.018) were higher in the ACLR/PF group than in the healthy group during walking. In addition, the results highlighted a significant difference in the muscle frequency content of the rectus femoris (P=0.012, d=0.68) and vastus latelarlis (P=0.042) during the loading response and push-off phase in the ACLR/PF group compared to the healthy group during walking. Discussion & Conclusion: Peak plantar pressure values at the midfoot region and rectus femoris and vastus lateralis muscular frequency content in the ACLR/PF group differed from that of the healthy group during walking. [ABSTRACT FROM AUTHOR]

Context: Limited research reveals that the use of different soft tissue mobilization techniques increases tissue mobility in different regions of the body. Objective: The purpose of this study was to determine whether there is a difference between administering instrument-assisted soft tissue mobilization (IASTM) and therapeutic cupping (TC) on hamstring tightness. Design: Subjects attended one session wherein treatment and leg order were randomized before attending the session. A statistical analysis was completed using a 2 (intervention) × 2 (time) repeated-measures analysis of variance at α level ≤.05. Participants: Thirty-three subjects between the age of 18–35 years old with bilateral hamstring tightness participated in this study. Interventions: The IASTM and TC were administered on different legs for 5 minutes and over the entire area of the hamstring muscles. One TC was moved over the entire treatment area in a similar fashion as the IASTM. Main Outcome Measures: The intervention measurements included soreness numeric rating scale, Sit-n-Reach (single leg for side being tested), goniometric measurement for straight-leg hip-flexion motion, and superficial skin temperature. The timeline for data collection included: (1) intervention measurements for the first randomized leg, (2) 5-minute treatment with the first intervention treatment, (3) intervention measurements repeated for postintervention outcomes, and (4) repeat the same steps for 1 to 3 with the contralateral leg and the other intervention. Results: There was a main effect over time for Sit-n-Reach, measurement (pre-IASTM—29.50 [8.54], post-IASTM—32.11 [8.31] and pre-TC—29.67 [8.21], post-TC—32.05 [8.25]) and goniometric measurement (pre-IASTM—83.45 [13.86], post-IASTM—92.73 [13.20] and pre-TC—83.76 [11.97], post-TC—93.67 [12.15]; P <.05). Conclusion: Both IASTM and TC impacted hamstring mobility during a single treatment using only an instrument-assisted soft tissue mobilization technique without any additional therapeutic intervention. [ABSTRACT FROM AUTHOR]

Context: The incidence of low back pain (LBP) is high among high school male soft tennis players. In some sports for which the rotational component of the body is important, an association between restricted hip internal rotation of the nondominant leg and LBP has been reported; however, whether this association holds in soft tennis is unknown. Therefore, this study aimed to evaluate the association between hip internal rotation, hip external rotation, hamstring flexibility, iliopsoas flexibility, and LBP incidence. Design: This study was designed as a cross-sectional study, conducted at a sports training center. Methods: Participants comprised 113 male elite high school soft tennis players (age: 16.1 [0.7] y) from 9 elite-level teams. The main outcome measures were the hip internal and external rotation range of motion, hamstring flexibility on the straight leg raise test, and iliopsoas flexibility on the Thomas test. Multiple logistic regression analysis was performed to examine the influence of main outcomes on LBP incidence in the past 1 year. Results: A total of 35 participants had LBP (LBP group); 78 participants did not have LBP (non-LBP group). Multiple logistic regression analysis revealed that the odds ratio for height was 1.08 (95% confidence interval, 1.00–1.16; P =.043) and for the hip internal rotation range of motion in the nondominant leg was 0.90 (95% confidence interval, 0.85–0.95; P <.001), indicating significant associations with LBP. Conclusion: Hip internal rotation range of motion in the nondominant leg and height were crucial factors related to LBP in male elite high school soft tennis players. [ABSTRACT FROM AUTHOR]

Background: While extensive research exists on muscle injuries among adult football players, a notable gap persists in studies concerning younger footballers. The aim of the current study is to provide epidemiological data on the characteristics of time-loss muscle injuries in young football players participating in the Italian Under-19 male elite Championship ("Primavera 1"). Results: Conducted as a multicentre, prospective, observational cohort study, this research gathered injury data from the 2022-23 season across 14 of the 18 Clubs in the first Italian Under-19 championship. The cohort comprised 391 players with a mean age (± standard deviation) of 18.0 ± 0.4 years. A total of 479 injuries were reported, resulting in 14,231 days of activity lost. Of these, muscle injuries were 209 (44%), accounting for 4,519 (32%) days lost. Overall muscle injuries incidence was 1.82/1000 hours, with a mean injury burden of 39.4 days lost/1000 hours. Almost all muscle injuries (206 out of 209: 98.5%) occurred in hamstrings, quadriceps, adductors, calf and iliopsoas. Hamstrings injuries were the most burdensome (18.8 days lost/1000 hours) accounting for nearly half of all days lost due to muscle injuries. Incidence and burden of adductors injuries (0.25 injuries and 4.1 days lost/1000 hours, respectively) were found to be comparable to calf injuries (0.24 injuries and 4.7 days lost/1000 hours, respectively). Iliopsoas injuries accounted for a noteworthy portion of the total, with an injury incidence of 0.16/1000 hours and a burden of 3.3 days lost/1000 hours. Injuries with myo-tendinous or myo-aponeurotic involvement demonstrated delayed return-to-football compared to those without such involvement (35.6 vs. 18.5 days, p < 0.0001). Conclusions: The study highlighted a peculiar distribution of non-contact muscle injuries among elite young football players. While hamstring injuries were confirmed as the most burdensome, incidence and burden of adductors and calf injuries were found to be similar. A significant incidence and burden of iliopsoas injuries were observed. These findings suggest potential implementations for targeted injury prevention strategies in the Italian male elite Under-19 football Championship. Key points: • In the Italian male elite Under-19 football Championship, each Club can expect around 15 non-contact muscle injuries during the season (for a team of 25 players) distributed as follows: 6 hamstrings, 3 quadriceps, 2 adductors, 2 calf and 1 iliopsoas muscle injuries. • Hamstrings injury incidence and burden (both in training sessions and during matches), as well as the proportion of reinjuries, were found to be the highest among muscle sites. • Injuries to adductors and calf muscles exhibited comparable values of incidence and burden. • Iliopsoas emerged as a noteworthy site of injury in the current cohort, particularly during training sessions. • Aponeurosis or tendon damage was associated with longer return to football timing, particularly in hamstrings and adductors injuries. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Patients with chronic kidney disease (CKD) on hemodialysis (HD) have muscle weakness in addition to a high risk of falls, motor impairment and immobilization To conduct a systematic review with meta-analysis of randomized clinical trials regarding the effectiveness of resistance exercises on muscle strengthening and lower limb endurance in patients with CKD on HD. The study was conducted in the PubMed, EMBASE, SciELO, LILACS and Cochrane databases, without linguistic restrictions or year of publication. Of the 824 studies found, only 6 were included for analysis. Studies were allocated to some concern or high risk of bias regarding the reporting of outcomes. The low quality of outcome evidence can mainly be observed due to the severe level of inconsistency owing to the high degree of heterogeneity. A significant reduction in heterogeneity was observed after the sensitivity analysis, demonstrating an improvement in the muscle strength of the lower limbs (p =.002). It is concluded that most studies demonstrate benefits in carrying out resistance training programs in increasing muscle strength of the lower limbs, however, it is necessary that randomized clinical trials (RCTs) with greater methodological rigor are performed to confirm these findings. [ABSTRACT FROM AUTHOR]