Role of vision in sighted and blind soccer players in adapting to an unstable balance task

Abstract

This study tested whether a compensatory hypothesis exists on postural control during standing unstable balance tasks comparing blind soccer players (n = 7) to sighted soccer players (n = 15) and sighted sedentary individuals (n = 6). All subjects performed a pre-test, a training of ten practice trials on a single day, and a post-test balance test. All tests were performed on an unstable surface placed on a force platform and under closed-eyes conditions, and a final test was performed with open eyes. Balance performance was assessed by resultant distance (RD) and the magnitude of mean velocity (MV) of the centre of pressure (CoP) displacement, and EMG signals from the gastrocnemius lateralis, tibialis anterior, rectus femoris, and peroneus longus were measured with surface electromyography. Principal component analysis (PCA) on EMG muscular activation was used to assess EMG pattern differences during the balance tasks. All groups improved their performance, obtaining low scores for the closed-eyes condition balance task after the training period in RD, VM, and aids received to keep balance in the novel task, and no differences were found between groups or in interaction effects. Sighted individuals and the control group showed significantly lower RD and VM scores under open-eyes conditions than blind participants. As regards neuromuscular behaviour, three principal patterns explained 84.15% of the variability in the measured data. The theoretical improvement of the other senses caused by visual deprivation does not allow blind individuals to obtain better balance than sighted individuals under closed-eyes conditions, thereby reinforcing the prominent role of vision in integrating and processing the other sensory inputs. In addition, blind individuals seem to increase their muscular co-activation as a safety strategy, but this behaviour is not different to that shown by sighted people under closed-eyes conditions.

Postural stability in people with visual impairment

“…Although several reports have been published regarding people with visual impairment (Al-Salem & Rawashdeh, 1992;Awad, Al-Eisa, & Alghwiri, 2014;Mansour et al, 1997;Tabbara, 2001;Tabbara & Badr, 1985), few of them have discussed the etio-pathogenesis of postural alteration and balance impairment in this population (Campayo-Piernas, Caballero, Barbado, & Reina, 2017;Kotb, Hammouda, & Tabbara, 2006); moreover, no previous study has investigated postural stability in people with visual impairment. This study was aimed to assess COG velocity in people with visual impairment and compared with that measured in sighted subjects.…”

The Effects of Transcranial Direct Current Stimulation (tDCS) Combined With Proprioceptive Training for Blind Individuals: The Study Protocol for a Randomized Controlled Clinical Trial

“…Rogge et al (15) showed that balance training is capable to improve balance performance in blind adults after 6 weeks at various types of balance exercises. Others have indirectly cited in studies quantifying PC in these individuals using moving platforms, with reports of improvements in balance following the sessions (1,3). Thus, the present study proposes a rehabilitation protocol for improving PC in blind individuals involving proprioceptive exercises combined with the administration of tDCS.…”

“…Postural control (PC) can be negatively affected in individuals with blindness due to the lack of availability of visual input (1,2). The proprioceptive system cannot completely compensate this poor balance for a lack of vision even on high demand for physical activity such as sports participation (3,4). Contributing factors in blind subjects include a lack of adequate information on the surrounding environment, spatial localization, and the orientation of body parts, which serve as a reference for perception and action in relation to the outside world (2).…”

Patterns of whole-body muscle activations following vertical perturbations during standing and walking

“…We observed that magnitude of muscle activation, for instance, was progressive: smallest after visual perturbations, followed by (physical perturbations) dynamiccamera, static-camera, and nally, eyes-closed conditions that usually led to largest magnitudes. Visual sensory cues have been suggested to be suitable for balance-control regulation [61,62], and for locomotion modulation related to surface inclination changes [35]. Understanding the multisensory integration determining muscle activation patterns for postural control can have translational bene ts for patients with sensory-integration dysfunctions, either to entrain compensations or to identify sources of sensory impairment.…”