The combined impact of a perceptual-cognitive task and neuromuscular fatigue on knee biomechanics during landing

Knee. 2019 Jan;26(1):52-60. doi: 10.1016/j.knee.2018.10.017. Epub 2018 Dec 22.


Background: A large majority of anterior cruciate ligament (ACL) injuries are non-contact, most often occurring during a landing or change of direction. Recent research indicates that cognitive factors may be involved in non-contact ACL injuries. The aim of this study was to determine if a game-situation perceptual-cognitive load leads to altered landing kinematics in physically fatigued female athletes.

Methods: Nineteen female recreational athletes were recruited to perform a series of jumping and landing trials. In a first phase, eight trials were performed in an isolated condition and eight were performed while participants performed a perceptual-cognitive task. Before a second identical phase, participants underwent a muscular fatigue protocol. Knee-joint kinematics were recorded and compared between conditions using paired t-tests.

Results: Muscle fatigue led to statistically significant increases in peak knee abduction and peak internal knee rotation as well as a decrease in maximum knee flexion, when comparing conditions without the perceptual-cognitive task. The perceptual-cognitive task had no statistically significant effect on any knee rotations, either pre- or post-fatigue. However, a subgroup of 12 athletes showed a significant increase in knee abduction in the presence of the perceptual-cognitive task, only in the fatigued condition.

Conclusion: A perceptual-cognitive task combined with muscle fatigue alters knee kinematics of landing for a subset of recreational athletes, potentially increasing the risk of ACL rupture. Further studies are necessary to confirm this finding and to identify characteristics of at-risk individuals to target them for injury prevention protocols.

Keywords: Cognitive load; Knee biomechanics; Landing; Multiple-object tracking (3D-MOT); Neuromuscular fatigue.

MeSH terms

  • Adult
  • Athletes*
  • Biomechanical Phenomena
  • Cognition / physiology*
  • Female
  • Humans
  • Knee Joint / physiology*
  • Male
  • Movement / physiology*
  • Muscle Fatigue / physiology*