LAUSR

Additional perspectives on Commentary bjsports-2017-098502: ‘ACL rupture is a single leg injury but a double leg problem: too much focus on “symmetry” alone and that’s not enough!’1 In the Commentary ‘ACL rupture is a single leg injury but a double leg problem…’, the authors argue that measurements of limb symmetry underestimate deficits. I mainly agree with the authors, but reason for when and how symmetry measurements should be used and also for the use of versatile test batteries . To choose adequate functional tests in the clinic and to design new test-batteries and rehabilitation programmes for individuals with ACL injury, I propose to look for answers and solutions in the extensive literature on motor control. Therefore, basics of motor control are recapitulated . No consensus exists on how to decide when to return to sports.2 Often, strength and hop tests are used, calculating an LSI (the ratio of injured/non-injured sides), and LSI >90% is frequently suggested as a cut-off criteria.3 However, individuals with ACL reconstruction rarely reach 90% symmetry.4 Moreover, impaired capacity on both sides after ACL injury is well known, underestimating deficits measured as LSI. Therefore, measurements of preinjury capacity or normative data of non-injured controls have been suggested, since they may be more sensitive in predicting second ACL injuries.5 Therefore, to meet the concerns of the double leg problem I argue for that when LSI is used, it should be interpreted in combination with applicable normative data of controls or …