## 4 Discussion
### Balance  
Findings from previous studies with a similar group-based mode of OEP delivery support our results on static and dynamic equilibrium [19; 49; 50] and further highlight the superiority of the group format for the OEP in improving static and dynamic balance compared to the individual format, as was also reported by a recent meta-analysis [20]. The balance improvement found in the present study could be explained by the multicomponent content of the OEP program which combined balance, strengthening, agility, coordination, and gait elements. Such multimodal regimens have been widely recommended by American, Canadian, and European Exercise Guidelines for improving balance and physical performance in elderly [51; 52; 53]. The resistance training exercises of the large muscle groups of the lower limbs enhance their strength and thus contribute to static balance as well as to more dynamic functional tasks, like gait [54]. Additionally, the tasks included in the OEP trained the participants in all balance domains, including static (through all standing tasks: standing on toes/heels, standing on one leg), dynamic (through walking tasks: forward, backwards, and sideways walking, walking on heels, walking on toes), and proactive balancing tasks (through changing position: knee bends, sit to stand from a chair). Further emphasis, in our study, was given to the timing at and with which the guidance was given to the OEP participants. The results of this pilot study did not reveal any difference between the advance or the parallel mode of guidance delivery, implying that the time that the visual and verbal guidance is given does not change the effectiveness of the OEP on balance and gait. The presence of guidance and of augmented feedback, such as that given to the groups of the present study, have been discussed as potential contributors to the process of motor learning and to self-efficacy and intrinsic motivation during the performance of a motor task [55]. The way the information is processed may also influence the successfulness of the motor performance. Short, precise verbal cues, linguistically appropriate for the age group have been suggested as helpful ways to teach a basic movement structure [56]. Studies have shown the importance of the visual and verbal cues in the rehabilitation process. In the study of [PERSON] et al. (2020), the static and dynamic balance ability of older adults was improved when they provided concurrent customized visual feedback during a slow and sustained single-leg training [57]. In the study of [PERSON] et al. (2020), the quality of gait was improved when a Heel-to-Toe sensor device was used in patients with Parkinson Disease to give real-time auditory feedback for each step of appropriate heel strike angle. The authors highlighted the importance of real-time feedback for gait rehabilitation because \"closer feedback to the time of action\" facilitates the learning process [58]. Even studies using the OEP modified formats, such as the OEP with augmented reality, delivered in a DVD format, reported improvements on balance and functional ability [59; 60]. Through the rich continuous audio-visual feedback that is provided by virtual reality technologies, the participant is enforced to concentrate, to quickly react to changes, to use visual-vestibular interaction, visuospatial memory, ocular motor skills, body perception, and sensory integration, thereby facilitating motor learning for balance rehabilitation and reducing the risk of falls [61]. However, still, these new augmented forms of rehabilitation, although very promising, have not been proved to be superior to conventional physiotherapy [27]. In addition, the use of virtual reality is not supported by high quality randomized trials and the results, although positive towards the improvement in balance, fear of falling, and gait, lack strong evidence [62; 63]. Until now, no study has explored the efficacy of the timing that the feedback and visual-verbal guidance is delivered in relation to balance and gait in the elderly.