THE EFFECTS OF THE EYES CLOSED CONDITION ON LEG MUSCLE ACTIVATION, GROUND REACTION FORCES, AND 3D KINEMATICS IN REPEATED COUNTERMOVEMENT JUMPS

Abstract

Background: The human body is a complex structure in which multiple systems interact to produce specific functions and well-coordinated movements. In order to perform any movement, postural control is needed, which is critical for both daily life activities and becoming independent. Visual stimuli along with other main sensory inputs (e.g. proprioception, sounds, smells, touch) can be considered as the basis of any movement. Absence of visual stimuli can increase the burden of high reliance on other sensory systems by performing sensory re-weighting. This experiment aims to investigate the effects of the eyes-closed condition on lower limb muscle activation, ground reaction forces, and 3-dimensional kinematics (performance) during repeated countermovement jumps in young male adults aged between 18 and 30 years. Methods: An experimental design was used with n=18 healthy male participants (mean ± standard deviation; age 23.7±4.3 years, height 173.8±7.4 cm, body mass 70.8±8.8 kg) who attended the Biomechanics Laboratory for one session to perform the experiment with randomized starting condition. Statistical analysis was performed on GraphPad Prism using tests for normal distribution, paired/unpaired t-tests, and correlation. Results: Within the same condition, eccentric and concentric range of motion and time showed significant difference with a p-value < 0.0001 (i.e., when comparing the eccentric phase to the concentric phase in the open eyes condition, and repeating the same method with the eyes closed). However, there was no significant difference in other variables when comparing the eyes open to the eyes closed condition. Conclusion: The present study can be considered as an initiative into investigating whether the eyes closed condition can be used in various settings for multiple populations, and can be the beginning of future research investigating this condition with different populations for a better understanding on how this method affects the performance, muscle activation, and body kinematics.

Date of Award	2024
Original language	American English
Awarding Institution	HBKU College of Health & Life Sciences