Jaccard H1, Meyer F2, Preatoni E3
1CHUV, Physiotherapy, Musculoskeletal Department, Lausanne, Switzerland, 2University of Lausanne, Institute of Sport Sciences, Lausanne, Switzerland, 3University of Bath, Department for Health, Bath, United Kingdom
Background: Motorised Rotating Platforms (MRP) may be used to train lower limb stability and neuromuscular control of the knee. Among the available MRP, imoove (AllCare Innovations, Chabeuil, France) induces a helispherical three-dimensional movement that may replicate, to a certain extent, knee kinematics that occurs during the ACL injury mechanism (flexion, abduction, internal rotation). Thus, MRP single leg exercise might be a highly specific exercise to train neuromuscular control of the lower limb and enhance unconscious motor response by stimulating afferent signals and central mechanisms responsible for dynamic joint control. However, less is known about the influence of MRP movement and its settings speed and amplitude on knee kinematics. A better understanding of MRP training and its effect on knee kinematics will allow physiotherapists to develop adequate exercises while remaining safe during ACL rehabilitation.
Purpose: The purposes of this study were to assess the influence of speed and amplitude of plate rotation on sagittal, frontal and transverse plane knee kinematics and to highlight any similarity between knee kinematics during single-leg MRP exercise and non-contact ACL injury mechanism.
Methods: 3D kinematic data were obtained from 20 healthy participants (♀ 25%; right leg dominance 45%, 26.7±5.4 years; weight 71.6±13 kg; height 175.4±10.1 cm, IKDC subjective score 97.14±4.9). Data were recorded during a 1-minute single leg balance exercise on imoove. 2 direction of plate rotation were assessed: posteromedial and posterolateral. A 2x2 factorial design was used to assess the influence of low and high speed and low and large amplitude on knee kinematics. Two-Way Analysis of Variance (ANOVA) repeated measures were performed through Statistical Parametric Mapping to see whether speed or amplitude or their interaction had an effect on knee kinematics in sagittal, frontal and transverse planes.
Results: Speed had a significant main effect on peak knee flexion during both posterolateral rotation (p=0.040) and posteromedial rotation (p=0.038). It also had a significant main effect on knee internal rotation during posterolateral rotation (p= 0.016). Amplitude had a significant main effect (p 0.001) on sagittal plane knee kinematics. Increasing MRP rotation amplitude induced larger knee flexion throughout the cycle. Frontal plane kinematics was influenced neither by speed nor by amplitude during posterolateral rotation. During posterolateral plate rotation, at high speed and large amplitude, knee kinematics displayed a flexion extension pattern and a mean peak flexion angle of 26° à 50% of th cycle. Knee also underwent an internal rotation of 6.2° (2.5 to 1.27) between 29 and 79% of the rotation cycle.
Conclusion(s): Knee kinematics during single-leg MRP exercise displayed some similarities with the ACL injury mechanism. Indeed, during posterolateral rotation of the plate, knee underwent concurrently flexion and internal rotation. However, no movement in the frontal plane was found. Physiotherapists should be aware of the influence of speed and amplitude of rotation on knee kinematics to safely implement such exercises during rehabilitation.
Implications: MRP training can be interesting in the context of ACL rehabilitation. MRP training may stimulate the ACL through its combined loading sagittal and transverse planes of movement during the posterolateral rotation of the platform.
Keywords: Motorised rotating plate, Knee kinematics, Anterior cruciate ligament
Funding acknowledgements: No funding
Purpose: The purposes of this study were to assess the influence of speed and amplitude of plate rotation on sagittal, frontal and transverse plane knee kinematics and to highlight any similarity between knee kinematics during single-leg MRP exercise and non-contact ACL injury mechanism.
Methods: 3D kinematic data were obtained from 20 healthy participants (♀ 25%; right leg dominance 45%, 26.7±5.4 years; weight 71.6±13 kg; height 175.4±10.1 cm, IKDC subjective score 97.14±4.9). Data were recorded during a 1-minute single leg balance exercise on imoove. 2 direction of plate rotation were assessed: posteromedial and posterolateral. A 2x2 factorial design was used to assess the influence of low and high speed and low and large amplitude on knee kinematics. Two-Way Analysis of Variance (ANOVA) repeated measures were performed through Statistical Parametric Mapping to see whether speed or amplitude or their interaction had an effect on knee kinematics in sagittal, frontal and transverse planes.
Results: Speed had a significant main effect on peak knee flexion during both posterolateral rotation (p=0.040) and posteromedial rotation (p=0.038). It also had a significant main effect on knee internal rotation during posterolateral rotation (p= 0.016). Amplitude had a significant main effect (p 0.001) on sagittal plane knee kinematics. Increasing MRP rotation amplitude induced larger knee flexion throughout the cycle. Frontal plane kinematics was influenced neither by speed nor by amplitude during posterolateral rotation. During posterolateral plate rotation, at high speed and large amplitude, knee kinematics displayed a flexion extension pattern and a mean peak flexion angle of 26° à 50% of th cycle. Knee also underwent an internal rotation of 6.2° (2.5 to 1.27) between 29 and 79% of the rotation cycle.
Conclusion(s): Knee kinematics during single-leg MRP exercise displayed some similarities with the ACL injury mechanism. Indeed, during posterolateral rotation of the plate, knee underwent concurrently flexion and internal rotation. However, no movement in the frontal plane was found. Physiotherapists should be aware of the influence of speed and amplitude of rotation on knee kinematics to safely implement such exercises during rehabilitation.
Implications: MRP training can be interesting in the context of ACL rehabilitation. MRP training may stimulate the ACL through its combined loading sagittal and transverse planes of movement during the posterolateral rotation of the platform.
Keywords: Motorised rotating plate, Knee kinematics, Anterior cruciate ligament
Funding acknowledgements: No funding
Topic: Musculoskeletal: lower limb; Human movement analysis; Sport & sports injuries
Ethics approval required: Yes
Institution: Canton of Vaud
Ethics committee: The Cantonal Ethics Commission for Human Research
Ethics number: 2017-00724
All authors, affiliations and abstracts have been published as submitted.
