Prevention of knee stiffness following ligament reconstruction: Understanding the role of Arthrogenic Muscle Inhibition (AMI).

The knee is a joint that is often injured in sport, with a large and increasing number of ligament tears and repairs; postoperative complications can lead to poor outcome, such as stiffness. Beyond the well-known and well-described intra- and extra-articular causes of postoperative stiffness, the present study introduces the concept of a central reflex motor inhibition mechanism called arthrogenic muscle inhibition (AMI). AMI occurs after trauma and can be defined as active knee extension deficit due to central impairment of Vastus Medialis Obliquus (VMO) contraction, often associated with spinal reflex hamstring contracture.

Relationship Between Nordic Hamstring Strength and Single Leg Bridge Test in University Soccer Players.

Context: Nordic hamstring strength (NH strength) and single leg bridge test (SLBT) scores are used to predict the risk of hamstring strain injury. Although NH strength and SLBT scores may be related, the relationship between NH strength and SLBT score remains unknown.

Objectives: This study investigated the relationship between NH strength and SLBT scores in university soccer players.

Practicing Outside the Lines: Using Acupuncture in the Athletic Training Room and on the Field.

Acupuncture can be used to treat athletes in an outpatient clinic setting, athletic training room, or even on a football field sideline. This article details 3 scenarios, in 3 illustrative cases, in which acupuncture was used for sports medicine in more unconventional settings. The author describes each case and shares his observations about them.

Use of Acupuncture, Myofascial Release Techniques, and Kinesiology Taping to Reduce Estimated Healing Time in A Grade 3 Hamstring Strain: A Case Study.

Background: Musculoskeletal injuries can be debilitatingly painful, with long recovery times and activity-limiting prognoses. While numerous studies and case reports illustrating the benefits of acupuncture in treating various musculoskeletal conditions are available, more studies specific to acute injury are needed.

Case: A 45-year-old male presents ∼48 hours post a severe injury to his R hamstring while walking in his neighborhood.

Hamstring muscle fibre typology is not associated with hamstring strain injury history or performance in amateur male soccer players: a retrospective magnetic resonance spectroscopy study.

Hamstring strain injuries (HSI) are still the most common injuries in soccer. Recent research has been focusing on the role of hamstring muscle morphology and architecture. The hamstring's fibre type composition might play a role as well, but this has never been investigated in the light of HSI risk in an athletic population.

Ischiofemoral Impingement Due to an Undiagnosed Pelvic Avulsion Fracture.

Ischial tuberosity (IT) avulsion fractures are an uncommon cause of injuries in athletes. In this case, a 26-year-old female suffering from posterior right hip pain for over a decade presented with debility and a decrease in athletic function. Notable history included a hamstring strain while sprinting in elementary school.

Exploring the Role of Sprint Biomechanics in Hamstring Strain Injuries: A Current Opinion on Existing Concepts and Evidence.

Hamstring strain injuries are one of the most common injuries in sprint-based sports with the mechanism of injury considered the result of an interaction between applied mechanical strain and the capacity of the muscle to tolerate strain. To date, injury prevention and rehabilitation strategies have frequently focused on enhancing the capacity of the hamstrings to tolerate strain, with little consideration of factors directly influencing mechanical strain. Sprint running biomechanics are one factor proposed to influence the mechanical strain applied to the hamstrings that may be modified (towards reduced strain) within rehabilitation and injury prevention programs.

Hamstring Strain Injury Risk Factors in Australian Football Change over the Course of the Season.

Background/aim: This study aimed to determine which factors were most predictive of hamstring strain injury (HSI) during different stages of the competition in professional Australian Football.

Methods: Across two competitive seasons, eccentric knee flexor strength and biceps femoris long head architecture of 311 Australian Football players (455 player seasons) were assessed at the start and end of preseason and in the middle of the competitive season. Details of any prospective HSI were collated by medical staff of participating teams.

The effects of high-velocity hamstring muscle training on injury prevention in football players.

Explosive and fast body movements, sprints, jumps and quick changes of direction, which are characteristic of the football training, place considerable strain on the hamstring muscles. Due to the high occurrence of hamstring injuries, new preventive strategies are required that focus on high-velocity training. The purpose was to assess the effectiveness of high-velocity elastic-band training in reducing the occurrence of hamstring injuries in football players.

Quantifying demands on the hamstrings during high-speed running: A systematic review and meta-analysis.

Introduction: Hamstring strain injury (HSI) remains a performance, economic, and player availability burden in sport. High-speed running (HSR) is cited as a common mechanism for HSI. While evidence exists regarding the high physical demands on the hamstring muscles in HSR, meta-analytical synthesis of related activation and kinetic variables is lacking.

Hamstring Strain Ultrasound Case Series: Dominant Semitendinosus Injuries in National Collegiate Athletic Association Division I Athletes.

Authors of previous studies of patients with acute hamstring strains have reported injury to the biceps femoris and semitendinosus (ST) in 50% to 100% and 0% to 30%, respectively. This retrospective case series of hamstring injuries in National Collegiate Athletic Association Division I collegiate athletes exhibited an injury pattern on ultrasound imaging that differed from what would be expected based on prior literature. We examined ultrasound images of 38 athletes with acute hamstring strains for injury location (proximal muscle, proximal myotendinous junction, midportion of muscle, distal muscle) and affected muscles (biceps femoris, ST, or semimembranosus).

Hamstring Strain Injury Prevention: Current Beliefs and Practices of Practitioners Working in Major League Baseball.

Context: Hamstring strain injury (HSI) is the most frequently sustained injury in Major League Baseball (MLB). However, the beliefs and practices of practitioners working in MLB regarding HSI risk factors and prevention strategies in baseball athletes have not been documented.

Objective: To document the current beliefs and practices of practitioners working in MLB regarding HSI prevention.

Synergistic Dominance Induced by Hip Extension Exercise Alters Biomechanics and Muscular Activity During Sprinting and Suggests a Potential Link to Hamstring Strain.

Iguchi, J, Hojo, T, Fujisawa, Y, Kuzuhara, K, Yanase, K, Hirono, T, Koyama, Y, Tateuchi, H, and Ichihashi, N. Synergistic dominance induced by hip extension exercise alters biomechanics and muscular activity during sprinting and suggests a potential link to hamstring strain. J Strength Cond Res 37(9): 1770-1776, 2023-Hamstring strain is likely to occur during the late swing phase or the first half of the stance phase in sprinting.

Aerobic high-intensity intervals improve V̇O more than supramaximal sprint intervals in females, similar to males.

Introduction: Maximal oxygen uptake (V̇O ) is a pivotal factor for aerobic endurance performance. Recently, aerobic high-intensity interval training (HIIT) was documented to be superior to sprint interval training (SIT) in improving V̇O in well-trained males. However, as mounting evidence suggests that physiological responses to training are sex-dependent, examining the effects of HIIT versus SIT on V̇O , anaerobic capacity, and endurance performance in females is warranted.

Intramuscular Tendon Injuries of the Hamstring Muscles: A More Severe Variant? A Narrative Review.

Hamstring strain injuries (HSI) are one of the most common sport-related injuries. They have a high injury burden and a high recurrence rate. The development of novel muscle injury grading systems has provided new insights into the possible impact of injury location on the time to return to play (TTRTP) and re-injury following HSI.

The Effect of the Nordic Hamstring Exercise on Muscle Activity: A Multichannel Electromyography Randomized Controlled Trial.

The aim of this study was to evaluate the effect of a Nordic hamstring exercise intervention on biceps femoris long head, semitendinosus, and semimembranosus muscle's activity and relative contributions through multichannel electromyography. Twenty-four injury-free male basketball players (mean age 20 [3] y) were randomly assigned to a 12-week intervention (n = 13) or control group (n = 11). The primary outcome measures were normalized muscle activity (percentage of maximal voluntary isometric contraction, %MVIC) and relative contribution of hamstring muscles over 12 weeks.

Speed Matters in Nordic Hamstring Exercise: Higher Peak Knee Flexor Force during Fast Stretch-Shortening Variant Compared to Standard Slow Eccentric Execution in Elite Athletes.

Hamstring strain injuries are prevalent in many sports. Research has demonstrated that the Nordic hamstring exercise (NHE), a knee-dominant exercise addressing the posterior chain muscles, can aid in reducing the risk of hamstring injuries in athletes. However, most research on hamstring injury prevention has focused on performing the eccentric version of the NHE (NHE).

Rugby Players Exhibit Stiffer Biceps Femoris, Lower Biceps Femoris Fascicle Length to Knee Extensors, and Knee Flexors to Extensors Muscle Volume Ratios Than Active Controls.

Purpose: This study aimed to determine if hamstring-strain-injury risk factors related to muscle structure and morphology differed between rugby union players and controls.

Methods: The biceps femoris long head (BFlh) fascicle length and passive muscle stiffness and relative and absolute muscle volume of knee flexors (KF) and extensors (KE) were measured in 21 male subelite rugby players and 21 male physically active nonathletes.

Results: BFlh fascicle length was significantly longer (mean difference [MD] = 1.

Intermuscular differences in force generation ability among biarticular hamstring muscles during the late swing phase in maximal speed sprinting.

We aimed to investigate how intermuscular muscle-tendon architectural differences among biarticular hamstring muscles (biceps femoris long head [BFlh], semimembranosus [SM] and semitendinosus [ST]) influence intermuscular differences in muscle force during the late swing phase in maximal speed sprinting. Using a musculoskeletal model, we estimated the muscle-tendon kinematics, muscle force，and force generation ability, defined by force-length-velocity properties and pennation angle, of the biarticular hamstring muscles in 40 male athletes during the late swing phase. SM force generation ability was smaller during the first half of the late swing phase and larger during the second half than the BFlh and ST.