21/01/2026
Hot off the Press🔥
𝗤𝘂𝗮𝗹𝗶𝘁𝗮𝘁𝗶𝘃𝗲 𝗮𝗻𝗱 𝗾𝘂𝗮𝗻𝘁𝗶𝘁𝗮𝘁𝗶𝘃𝗲 𝘀𝗶𝘁𝘂𝗮𝘁𝗶𝗼𝗻𝗮𝗹 𝗰𝗵𝗮𝗿𝗮𝗰𝘁𝗲𝗿𝗶𝘀𝘁𝗶𝗰𝘀 𝗼𝗳 𝗺𝘂𝘀𝗰𝗹𝗲 𝘀𝘁𝗿𝗮𝗶𝗻𝘀 𝗶𝗻 𝘀𝗽𝗼𝗿𝘁𝘀: 𝗮 𝘀𝘆𝘀𝘁𝗲𝗺𝗮𝘁𝗶𝗰 𝗿𝗲𝘃𝗶𝗲𝘄 𝗮𝗻𝗱 𝗺𝗲𝘁𝗮-𝗮𝗻𝗮𝗹𝘆𝘀𝗶𝘀
📘 A brand-new systematic review and meta-analysis by Finnern and colleagues (2026, https://bjsm.bmj.com/content/early/2026/01/20/bjsports-2025-110327) examined the situational and biomechanical characteristics of indirect and non-contact muscle injuries across a range of sports, with the aim of identifying consistent injury patterns that could inform prevention and clinical practice. Drawing on video-based analyses from 21 studies encompassing 728 injuries, the authors synthesized both qualitative descriptors (such as contact mechanisms and injury-inciting activities) and quantitative measures (including joint positions and movement directions at the assumed moment of injury).
The findings indicate that non-contact mechanisms predominate, accounting for approximately three-quarters of all cases. Injuries most frequently occurred during running or sport-specific actions involving rapid lengthening of the muscle–tendon unit under high levels of active contraction. Despite these shared features, distinct kinematic patterns emerged for different muscle groups. Hamstring injuries were commonly associated with a nearly extended knee and a flexed hip, particularly during late swing or high-speed running. Adductor injuries typically involved rapid hip extension, abduction, and external rotation, often during kicking or reaching movements. Re**us femoris injuries were characterized by concurrent hip flexion and knee extension, while calf injuries most often occurred with the ankle in marked dorsiflexion and the knee close to full extension.
Across team sports, running and kicking were the most prevalent injury-inciting activities, and injuries were distributed relatively evenly between the first and second halves of match play. Methodological quality varied among included studies, though most demonstrated moderate to good rigor in video analysis procedures.
Overall, the review highlights that while general principles of muscle strain causation—such as high muscle activation at long muscle lengths—apply broadly, injury patterns show meaningful variation by muscle group and sport context. The authors conclude that integrating these situational and biomechanical insights into training design, clinical assessment, and prevention strategies may improve the effectiveness of interventions aimed at reducing muscle injury incidence.
📸 Illustrations of situational patterns for indirect and non- contact muscle injuries (muscle strains). Please note that only a selection of the most common injury patterns based on included studies is illustrated (acknowledging the predominance of studies investigating male football players).
▶️ (A-I) Hamstring (running/sprinting): hamstring injuries are frequently seen during high- speed running or acceleration phases. Modelling studies and case reports identified the open-chain late swing phase as being most vulnerable to injury. During this phase of the gait cycle, the muscle-tendon unit of the biceps femoris lengthens. However, confirmation of this finding appraising systematic real- world video data is yet to be done, and the specific running phase in which athletes are most vulnerable to hamstring injury remains a matter of debate.
▶️ (A- II) Hamstring (closed kinetic chain lunging injury pattern): the athlete performs a decelerating closed kinetic chain manoeuvre. At the assumed time of injury, the knee joint is close to full extension, the hip joint is in a flexed position (ie, lunging position).
▶️ (A- III) Hamstring (open-chain kicking or reaching injury pattern): open-chain injury patterns are typically observed during kicking or reaching manoeuvres. Injury kinematics comprise a flexed hip joint combined with an extending knee joint movement.
▶️ (B- I) Adductor (closed-chain change of direction injury pattern): changes of directions are common situational patterns for adductor muscle injuries. The athlete performs a change of direction to catch a ball opposite to the moving direction. At the assumed time of injury, the injured leg is abducted and externally rotated while the adductor muscles are simultaneously activated to perform the deceleration and change of direction manoeuvre.
▶️ (B- II) Adductor (closed-chain or open-chain reaching injury pattern): the athlete performs a reaching manoeuvre with the non-injured leg towards the ball. At the assumed time of injury, the adductor muscle- tendon unit of the injury leg is lengthening due to hip extension, hip abduction and hip external rotation.
▶️ (B- III) Adductor (open-chain kicking injury pattern): this injury pattern shows similar injury kinematics (including hip abduction and external rotation) but is an open- chain injury pattern due to the player’s intention of kicking a ball with the injury-sided leg.
▶️ (C–) Quadriceps (open- chain kicking injury pattern): a commonly observed injury kinematic of quadriceps injuries comprises a flexing hip joint and extending knee joint movement (ie, kicking manoeuvre).
▶️ (D- I) Calf (closed-chain stepping back injury pattern): in the illustrated example, the athlete is setting off to take a run (e.g, by performing a back- step manoeuvre). These manoeuvres are seen in running or football and are common in I racquet sports (leading gastrocnemius muscle injury to be named ‘tennis leg’) or basketball. The underlying joint movements are ankle dorsiflexion and knee extension, thereby lengthening the calf muscle tendon unit. At the assumed time of injury, the knee is close to full extension, the ankle in >10° dorsiflexion and the foot in external rotation.
