Experimental design and setting
RECRUITMENT
The experimental design for the study is a prospective, cluster-based Randomized Controlled Trial (RCT). There are a total of 95 communities in Khon Kaen province, Thailand. The lead investigator ZX opened up discussions with the leaders of ten different communities, to whom they had been introduced by a senior staff member at Khon Kaen University (KKU), regarding whether the community they represented would be interested to participate in the study. The ten communities were relatively close to KKU which would make administration of the SSG training programme more straightforward and were similar in terms of socioeconomic and other demographic factors. The decision was made that as soon as two communities confirmed that they would like to participate the study would proceed. Thus the names of these two communities were each placed inside a sealed envelope and by random selection by ZX the first community to be drawn was assigned to be the Exercise Group and the second community to be the Control Group.Since, as already mentioned, of special interest in the present study is whether SSG training can have a beneficial effect on forward head posture which develops in many older adults, sample size for the Exercise and Control Groups was chosen based on a previous study of the effect of an intervention which aimed to improve posture. In particular, data obtained by Widberg et al. (2009) [The study was approved by the Research Ethics Committee of Khon Kaen University, Thailand on 1 March 2019 (HE 612355), and was registered retrospectively with the Clinical Trials Registry of Thailand on 9 July 2020 (TCTR20200709001) consistent with procedures for RCTs in which no medications are prescribed. The authors confirm that all ongoing and related trials for this intervention are registered. Recruitment took place between 10 March and 31 October 2019 and all participants gave fully informed written consent of their willingness to participate.The CONSORT 2010 Flow Diagram containing details of participant enrolment and progress through the RCT is displayed in 