[home] [Personal Program] [Help]

---

Session: Neuromuscular – lower extremities 1
Session starts: Friday 25 January, 10:30
Presentation starts: 10:45
Room: Lecture room 536

---

Jim Schrijvers ()
Josien van den Noort ()
Martin van der Esch ()
Jaap Harlaar ()

Abstract:
Purpose: In patients with disorders of the knee, abnormal loading and instability could be related to impaired neuromuscular control of the knee. Controlled perturbations during gait are used to provoke neuromuscular control. Studies investigating this are often limited to one perturbation type with a fixed intensity. This retains the question how neuromuscular control will respond to various gait perturbations. Therefore, the aim was to compare the effect of four perturbation types, each with five intensities, on the neuromuscular control of the knee during gait in healthy subjects. Methods: A pilot study was performed with eight healthy young subjects (24.4±1.7y) walking (1.2m/s) on an R-mill instrumented treadmill. After unperturbed walking, 20 walking trials were performed with perturbations applied during the stance phase of the right leg. Four perturbation types were tested: acceleration & deceleration of one belt and left & right sway of the treadmill. Five intensities were used per perturbation type. Electromyography was recorded of the medial and lateral muscles surrounding the knee. Repeated measures ANOVA were performed between the perturbation types and intensities using peak, root mean squared (RMS), summation over gait cycle (SUM) and co-contraction index (CCI) values of the electromyography signals. Results: Peak, RMS, SUM and CCI values of all muscles combined (medial + lateral) changed with increasing perturbation intensity (p<0.05) or with the use of different perturbation types (p<0.05). No differences were observed in the peak and CCI values in the lateral muscles with increasing perturbation intensity. Moreover, no differences were present between perturbation types in the peak and CCI values of the lateral and medial muscles. At the individual muscle level, some changes in peak, SUM and RMS values were present between the various gait perturbations. Conclusion: Subtle changes in neuromuscular control of the knee occur in response to various gait perturbations. Increasing the perturbation intensity seems to raise the overall muscle activation and using various perturbation types appeared to provoke different neuromuscular responses. The results of this study could be used as a reference to further explore gait perturbations in patients with knee disorders.