Motor control of fast voluntary elbow movements : exercise-induced muscle damage and soreness and learning interventions
Year: 2011
Type: dissertation
Abstract: (PDF)Diss.The aim of the present series of studies was to examine if exercise-induced muscle damage would result in similar phenomena in young and healthy men than those observed in deafferented patients.Moreover, it was examined if voluntary movement range had an effect on responses.Modulations of associated electromyographic (EMG) activity patterns were compared to stretch reflex responses.Through the acute practice of target movement (TM), it was examined if performance improvement was related to decreased terminal oscillation and refinement of associated EMG activity patterns.The exercise did not disturb extension-TM, such as observed in deafferented patient.On the contrary, flexion-TM was acutely deteriorated while rhythmic movement (RM) preserved intact.The performances were changed the most at small elbow angles and at 2 h post-exercise.The changes were associated with the agonists' decreased EMG amplitudes and changed timing (flexion-TM), and with the drop in flexor EMG amplitudes (RM).The reduction of EMG amplitudes was parallel to reduced active stretch reflex amplitudes.The one exercise protocol led to delayed increase of flexor EMG activity in RM.During the acute practice of TM, the increase of antagonist and agonist 2nd bursts relation, the decreased co-activation of these bursts, and the decrease of movement terminal oscillation was associated to improvement of movement time.To conclude, the present eccentric exercises did not have clear joint angle (muscle-length) specific effect on fast voluntary movements' motor control.The central nervous system seemed to use EMG amplitude modulation, in order to optimize the performance during muscle fatigue, damage, and soreness.The acute EMG findings suggested the inhibitory reflex effect originated most likely from group III / IV mechanonociceptors.The delayed modulations of movements' kinetics, kinematics and associated muscle activities referred to adaptive changes in motor control.The practice related modulations of TM reciprocal terminal oscillation suggested the involvement of reflex control refining the co-ordination of antagonistic muscles to enhance joint stiffness.
Author: Reijo Bottas
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2125743450