Extended Abstract
1. Introduction
Quality of Life (QOL) is an important indicator in health evaluation, and is effective in improving the mental and physical health of older people. The World Health Organization defines QOL as “an individual’s perception of their position in life in the context of the culture and value systems in which they live, and in relation to their goals, expectations, standards and concerns” [1]. One of methods that may affect QOL is physical activity based on intergenerational programs. An intergenerational program is a form of human service that involves ongoing and organized interaction between members of younger and older age groups for the benefit of all participants The purpose of this study was to examine the effect of physical activity based on Intergenerational programs on the elderlies’ QOL [2]. We used the dynamic aging approach as a theoretical framework [3, 4].
2. Methods & Materials
This is a quasi-experimental study with pre-test, post-test design using control group. The study samples were 150 older adults (mean age, 71.4±78.50 years) and 100 students (mean age, 21.86±2.62 years) living in Mashhad, Iran in 2017, who were entered into the study by using a convenience sampling method. The Research Ethics Committee of Islamic Azad University, Mashhad Branch has approved this study (Code: IR-IAU-MSHD.REC.1397.027). All participants were informed of their right to withdraw from the study at any time and written consent was obtained from all the participants. Entry criteria included the ability to perform physical activities, no any sensory and motor deficits, the use of antidepressants, Alzheimer's or physical disease, or the history of any particular disease that may endanger one's health by exercising. 
The participants were randomly divided into three groups including two experimental groups (In one group,  older adults received intergenerational programs for 8 weeks plus aerobic exercises in the presence of young adults, and in other group they received intergenerational programs only) [6]; and one control group where participants performed their daily routine activities without any intervention. Data collection tool included a demographic form, Socio-Economic Status Questionnaire (with a reliability of α=0.800)[7] and The World Health Organization Quality Of  Life, BREF (WHOQOL-BREF)  (with a reliability of α=0.875) [1]. After collecting data in two stages (before and after intervention), the data were analyzed in SPSS V. 25 by using descriptive and inferential statistics; two-way ANOVA was used to determine the interaction effect of demographic variables and groups on QOL; multivariate ANOVA for between- and within-group comparison of the mean of QOL dimensions in three groups; and Tukey's post hoc test to examine the difference between the study groups. The significance level was set at P<0.05.
3. Results
The normality of demographic data distribution was tested by using the Kolmogorov-Smirnov test (F144, 5= 0.637, P>0.05). Then, the homogeneity of variance was assessed by Levene’s test whose results showed no significant difference between groups at the pre-test stage (F144, 5=0.637, P>0.05). The results showed no significant interaction effect of group and demographic variables (P>0.05), but economic status significantly affected the elderlies’ QOL (P≤0.05). The results of Tukey's post hoc test showed that very poor and poor economic status had the highest mean difference. The QOL was significantly influenced by the levels of the groups as independent variable (P≤0.01); therefore, the effect of different types of interventions on the QOL dimensions including Psychological, Physical health, Social relationships and Environment, was investigated.
The homogeneity of variance for QOL dimensions was measured by the Levene’s test in the pre-test phase whose results supported the homogeneity assumption (P>0.05). The results of ANOVA showed a significant difference between in the mean scores of QOL dimensions between the three groups (P≥0.01). According to the results of Tukey's post hoc test, the mean scores for all four dimensions in the two experimental groups were significantly higher than in the control group (P≥0.01). Although the mean scores in two experimental groups were different after the intervention, but the difference was not statistically significant (P>0.05). In comparing the pre-test and post-test mean scores of all four QOL dimensions, the results indicated a significant increase in the scores after intervention with aerobic exercise (81.56±17.87) and without aerobic exercise (75.28±18.59) compared to the pre-test scores and the control group (P<0.01). In the control group, however, little changes were observed in the post-test scores (42.28±3.21) in all dimensions compared to the pre-test scores (39.45±12.47), but this difference was not statistically significant (P>0.05) (Table 1).
4. Conclusion
Comparing the results of the two experimental groups showed that the presence of young people can improve the QOL of the elderly people. Intergenerational programs along with physical activity can be effective for empowerment of the elderlies and youth. The effect of physical activity on QOL in our study can be related to positive psychological factors of self-efficacy, physical self-esteem and positive affect. Intergenerational programs can indirectly improve the social participation of the elderly people and affect their health and QOL. This improvement can be due to factors such as psychological factors which can have long-term effects on the well-being. Therefore, these programs can be used in various settings for the elderly, such as family, nursing homes and nursing care centers.

Ethical Considerations
Compliance with ethical guidelines
Ethical considerations in all phases of the study include participants ' awareness of the subject matter and procedure before the start of the study, obtaining informed consent from the samples, ensuring the confidentiality of the subject's personal information, interpreting personal results for enthusiastic individuals, lack of financial burden for participants and non-contradictory research was taken into account by the religious and cultural standards of the subject.
Funding
This article has received no funding
Authors' contributions
Design study, Manuscript preparation: Zeanat Ebrahimi, Mohammad Reza Esmaeilzadeh Ghandehari; Analysis and collection data: Zeanat Ebrahimi, Kourosh Veisi; All authors have read and approved the final version 
Conflicts of interest 
The authors declare that there are no competing interests
Acknowledgements
We would like to thank the participating elderly and university students, the dear authorities of the elderly care centers and Mashhad Islamic Azad University, and all those involved in this study.