Kinematic and Kinetic Risk Factors Exist Bilaterally During the First and Second Landing of the Drop Vertical Jump in Adolescent Patients following ACL Reconstruction.
Katie Sloma, Ashley Erdman, Ava Davis and 4 others
PMID 41048422WHAT IT FOUND
Adolescents cleared to return to sport after ACL surgery showed risk factors on both landings of a drop jump.
The second landing was stiffer and more game-like. The non-operated leg often moved more than the surgical leg, suggesting compensation rather than normal movement.
Key findings
01The second landing of the drop vertical jump resulted in stiffer mechanics, with significantly less hip and knee flexion compared to the first landing.
02Biomechanical risk factors were present in both the surgical and non-surgical limbs, with the non-surgical limb often showing greater movement deviations.
03Current screening tools that focus only on the first landing may miss risk factors that appear during the second, more game-like landing.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study did not include a healthy control group, so it is unclear if the observed asymmetries are normal or specific to post-ACL patients. The sample had uneven numbers of male and female participants, which may affect generalizability given known sex differences in landing mechanics. The mechanism of injury (contact vs. non-contact) was not recorded, so results cannot be tailored to specific injury types. Instructions for the second landing were not standardized, which may have influenced how participants performed the task. Some statistical differences were very small (less than 3 degrees) and may not be visible or clinically meaningful during a standard physical exam.
Declared interests
The authors declare no conflicts of interest.
The easy way to misread this
Do not assume the non-surgical limb is 'healthy' or 'normal' because it moves more. The study shows it often carries greater load and risk factors, suggesting compensation rather than optimal function. Also, do not dismiss the second landing as irrelevant; its stiffer mechanics may better reflect game-like injury risk.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →