Dean Johannes Kriellaars

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Repetitive firing of motoneurones was examined in decerebrate, unanaesthetised, paralysed cats in which fictive locomotion was induced by stimulation of the mesencephalic locomotor region. Repetitive firing produced by sustained intracellular current injection was compared with repetitive firing observed during fictive locomotion in 17 motoneurones. During(More)
The descending pathways from the brainstem locomotor areas were investigated by utilizing reversible cooling (to block synaptic or fiber transmission) and irreversible subtotal lesions of the brainstem or spinal cord (C2-C3 level). Experiments were conducted on decerebrate cats induced to walk on a treadmill by electrical stimulation of the brainstem.(More)
The spinal neurons involved in the control of locomotion in mammals have not been identified, and a major step that is necessary for this purpose is to determine where these cells are likely to be located. The principal objective of this study was to localize lumbar spinal interneurons activated by stimulation of the mesencephalic locomotor region (MLR) of(More)
The synaptic pathways of mesencephalic locomotor region (MLR)-evoked excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) recorded from lumbar motoneurons of unanesthetized decerebrate cats during fictive locomotion were analyzed prior to, during, and after cold block of the medial reticular formation (MedRF) or the low thoracic ventral(More)
1. We examined the ability of muscular and joint afferents from the hip region to entrain fictive locomotion evoked by stimulation of the mesencephalic locomotor region in the decerebrate cat by mechanically imposed, sinusoidal hip flexion and extension movements. 2. A method is presented for qualitative and quantitative analysis of entrainment. 3. Hip(More)
BACKGROUND The purpose of this study was to determine whether current post-operative rehabilitation protocols return the strength of the contralateral uninjured limb knee flexors and extensors after an anterior cruciate ligament (ACL) reconstruction to those of an uninjured control group. METHODS Subjects with a hamstring tendon ACL reconstruction (n=12)(More)
PURPOSE The purpose of this study was to examine the strength of the knee flexors and knee extensors after two surgical techniques of ACL reconstruction and compare them to an age and activity level matched control group. METHODS Twenty-four subjects who had undergone ACL reconstruction greater than 1 yr previously were placed into one of two groups(More)
Muscle series elasticity and its contribution to eccentric moment generation was examined in humans. While subjects [male, n = 30; age 26.3 +/- 4.8 (SD) yr; body mass 78.8 +/- 13.1 kg] performed an isometric contraction of the knee extensors at 60 degrees of knee flexion, a quick stretch was imposed with a 12 degrees -step displacement at 100 degrees /s.(More)
Extracellular recordings from interneurons located in the L4 spinal segment were made during fictive locomotion produced by electrical stimulation of the mesencephalic locomotor region (MLR) in the paralysed decerebrate cat. Only interneurons within the L4 segment which received group II input from quadriceps, sartorius or the pretibial flexor muscle(More)
OBJECTIVE The objective of this study was to determine whether there is alteration in resultant joint moment of the hip extensors and adductors after hamstring anterior cruciate ligament (ACL) reconstruction. DESIGN Cross-sectional outcome analysis. SETTING University sport medicine center. SUBJECTS Fifteen subjects more than 1 year after ACL(More)