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Development of valid diagnostics to evaluate sensorimotor competence in patients with anterior cruciate ligament (ACL) injury

English title Development of valid diagnostics to evaluate sensorimotor competence in patients with anterior cruciate ligament (ACL) injury
Applicant Baur Heiner
Number 176060
Funding scheme Project funding (Div. I-III)
Research institution Fachbereich Gesundheit Berner Fachhochschule
Institution of higher education Berne University of Applied Sciences - BFH
Main discipline Rehabilitation
Start/End 01.01.2018 - 31.12.2020
Approved amount 145'660.00
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All Disciplines (2)


Keywords (10)

anterior cruciate ligament; conservative therapy; electromyography; knee injury; knee joint; reconstructive surgery; return to sports; stretch reflex; sensorimotor training; neuromuscular training

Lay Summary (German)

Verletzungen Verletzungen und Rupturen (Risse) des vorderen Kreuzbandes passieren häufig bei körperlicher Aktivität. Es handelt sich um eine Knieverletzung mit nachhaltigen Konsequenzen (z.B. Risikoanstieg einer Knorpeldegeneration). Eine situativ passende Aktivierung der Muskulatur, die aktiv das Gelenk stabilisiert, ist wichtig, um passive Strukturen im Knie zu schützen. Allerdings gibt es noch zu wenige Daten zum Einfluss der Verletzung auf das Aktivierungsmuster der kniestabilisierenden Muskulatur. Das Projekt erhob bei Personen 12 Monate nach der urprünglichen Verletzung die Muskelaktivität der knieumgreifenden Muskulatur und konnte dabei im Mittel erhebliche Abweichungen zu den Aktivitätsmustern von (Kreuzband)gesunden Personen feststellen. Dies legt nahe vermehrt als bisher auf neuromuskuläre Trainingsformen in der Rehabilitation zu fokkussieren.
Lay summary

Inhalt und Ziele des Forschungsprojektes

Rupturen des vorderen Kreuzbandes können konservativ (Physio- & Trainingstherapie) oder operativ (Rekonstruktion des Kreuzbandes) versorgt werden. Beiden Optionen ist gemein, dass in der Rehabilitation auf eine angemessene Ansteuerung der kniestabilisierenden Muskulatur Wert gelegt wird. Die Fähigkeit je nach situativer Anforderung die Muskulatur adäquat einzusetzen, kann als „sensomotorische Kompetenz“ bezeichnet werden. Meist erfolgt im Rahmen der Rückführung an das ursprüngliche Aktivitätsniveau, neben der Beurteilung der passiven Stabilität, eine Testung der motorischen Fähigkeiten (z.B. Sprungtests). Interpretationen über die Funktion des Knies sind auf dieser Grundlage wenig spezifisch. Das Projekt hat zum Ziel Defizite der sensomotorischen Kompetenz durch Erhebung der muskulären Aktivität bei Patientinnen und Patienten objektiv messbar zu machen. Dies wurde durch die Messung der willkürlich erzeugten Muskelaktivität beim Treppensteigen und durch die Messung der Reflexaktivität nach einer künstlich eingeleiteten Störung der Standstabilität erreicht werden. Sowohl die willkürlich erzeugten Bewegungsmuster als auch die reflexive Antwort auf einen externen Störreiz sind 12 Monate nach der Verletzung immer noch im Vergleich zu gesunden Personen bei Personen mit vorhergehender Verletzung stark verändert. Dies deutet darauf hin, dass sensomotorische Trainingsformen in der Rehabilitation in zu geringem Umfang eingesetzt werden und darauf besonderes Augenmerk gelegt werden sollte, bevor sportmotorische Tests und Bewegungsformen eingesetzt werden.

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts

Das Projekt befasst sich mit anwendungsorientierter Grundlagenforschung. Die Entwicklung einer aussagekräftigen Diagnostik der sensomotorischen Kompetenz ist grundlagenorientiert. Gleichzeitig können Erkenntnisse daraus unmittelbar in Trainings- und Therapieprozesse der Prävention und Rehabilitation einfliessen.

Direct link to Lay Summary Last update: 25.03.2021

Lay Summary (English)

Injuries and ruptures of the anterior cruciate ligament (ACL) are frequent during physical activity. It is a knee injury with substantial consequences (increase in risk for cartilage degeneration). Adequate neuromuscular control stabilizes the knee actively to protect passive knee structures. However, knowledge on the influence of ACL injury on the neuromuscular control of knee-stabilizing muscles is still sparse. The project recorded the knee-stabilizing muscle activity 12 months after the initial injury. In general, considerable deviations from the activity patterns compared to healthy people can be observed. This suggests to focus way more on neuromuscular training forms in rehabilitation.
Lay summary

Content and objectives of the research project

Ruptures of the anterior cruciate ligament can be treated conservatively (physiotherapy and training therapy) or surgically (ACL reconstruction). Both options have in common that in rehabilitation focus is put on appropriate control of the knee-stabilizing muscles. The ability to use the muscles adequately, depending on the requirements of the situation, can be described as "sensorimotor competence". Usually, during the return process to the previous activity level assessments of passive knee stability is performed. Additionally, motor skills (for example jump tests) are tested. Interpretation about knee function based on these assessments is not very specific. The aim of the project is therefore to develop a diagnostic framework to objectively measure deficits of sensorimotor competence by evaluating muscular activity in ACL patients under various conditions. This was achieved by measuring the voluntarily generated muscle activity when climbing stairs and by measuring the reflex activity after an artificially induced disturbance of postural control. Both the voluntarily generated movement patterns and the reflexive response to an external disturbance stimulus are still significantly changed 12 months after the injury compared to healthy people. This indicates that sensorimotor training forms are used to a limited extent in rehabilitation and that special attention should be paid to this before physical performance tests and sport specific movements are used in training therapy.

Scientific and social context of the research project

The project deals with a combined basic and applied research question. The development of a meaningful diagnosis of sensorimotor competence is basic research. At the same time, findings can be transferred directly to training and therapy processes in prevention and rehabilitation.

Direct link to Lay Summary Last update: 25.03.2021

Responsible applicant and co-applicants


Project partner


Neuromuscular activity during stair descent in ACL reconstructed patients: A pilot study
Busch Aglaja, Blasimann Angela, Henle Philipp, Baur Heiner (2019), Neuromuscular activity during stair descent in ACL reconstructed patients: A pilot study, in The Knee, 26(2), 310-316.


Injury of the anterior cruciate ligament (ACL) is a frequent injury in physically active people. ACL ruptures can be treated non-surgically or surgically. Regardless of treatment modality, the initial consequences of an ACL tear are poor knee related quality of life, decreased knee function, decreased activity level and eventually detrimental effects on adjacent structures such as menisci and surrounding cartilage. Physiotherapy comes into play either directly in non-surgical treatment approaches or in rehabilitation after reconstructive surgery. Most (80%) of all ACL injuries are non-contact episodes happening during deceleration and acceleration motions with excessive quadriceps contraction or insufficient hamstrings activation at or near full knee extension. Thereby, the tibia is translated anteriorly relatively to the femur and stresses the ACL. Normally, the hamstring muscles act synergistically to this translational movement, whereas the quadriceps muscles are hamstrings and ACL antagonist. It has been shown, that non-contact ACL ruptures happen 17-50ms after initial contact, leaving a short time frame for mechanosensory feedback (e.g. reflex response). Pre-activity and re-active neuromuscular responses regulate muscle and joint stiffness, which is influencing dynamic joint stability, consequently influencing ACL (re)injury risk. Monitoring neuromuscular control of ACL-synergists and antagonists during exactly this time window from preactivity to perturbation onset and reflexive time windows after joint (stability) perturbation gives insight into sensorimotor control mechanisms establishing knee joint stability.The aim of this study is therefore to compare the reflex response of ACL-intact (healthy) subjects (n = 30) compared to surgically treated (n = 30) and compared to conservatively treated patients one year after injury (n = 30) during artificially induced tibia perturbation (simulation of injury mechanism; Bruhn 2011). Moreover, the neuromuscular response in stairway walking (ascent/descent), as an activity of daily life, as a second more functional task requiring adequate muscle activity will be assessed. This will be done in a cross-sectional study where surface EMG is measured in the above-mentioned situations. It is hypothesized that, because of different and altered afferent feedback, neuromuscular quadriceps / hamstring EMG activity differs between cohorts. Data on possible differences is sparse. Subjects with former ACL injury may have developed different neuromuscular strategies from subjects who have never torn their ACL. Pilot data following acute ACL injury indicate substantial changes in the motor program, even for the unaffected extremity. These differences give insight into dynamic joint stability, which can be used in prevention, rehabilitation and for return to sport decision making. Currently these decisions are based in subjective clinical assessments (passive stability) and physical test batteries (e.g. hop tests). Additional objective neuromuscular data closes the gap between the two mentioned currently available evaluations.In general, considerable alterations in neuromuscular activity pattern can be observed 12 months after the initial injury with no difference between surgically or conservatively treated patients. Voluntary activation in stariway walking as well as stretch reflex response after artificially induced tibia perturbation is different (lower activation) compared to healthy controls. Consequently, this project generates additional knowledge on sensorimotor deficiencies following ACL injury. The broader impact is evident because direct transfer of results to improvement of clinical decision-making (rehabilitation adjustment, return to sport / play decision making) is possible (Wellsandt 2017, Zebis 2017). The results indicate, that neuromuscular deficits after ACL rupture and rehabilitation are still evident 12 months after injury occurrence. This indicates that current "real-life" rehabilitation settings fail to address sufficient neuromuscular control mechanisms. Sensorimotor training forms should be put more into the focus during rehabilitation.