Recruitment
Due to the COVID-19 pandemic, various amendments were required to ensure that recruitment could continue. Alternative consent and questionnaire data collection processes were added, including the electronic completion of the consent form by participants via an online form, the collection of participant screening and baseline questionnaire data via telephone and the entry of this data electronically via an online form by study investigators. Circumstances that would make a participant unable to participate in an online yoga class were added to the exclusion criteria. These included no internet access, unfamiliar or unable to use the internet, no suitable device, insufficient space at home and no sturdy chair for use in the classes. It was also specified that potential participants needed to be available to attend 9 of the 12 classes. The method of contacting a patient to inform them of their ineligibility or eligibility (and therefore group allocation) was updated to say that this will either be done via telephone, e-mail or letter. Another amendment associated with recruitment challenges due to the COVID-19 pandemic was reconsidering the sample size in October 2021. This meant that recruitment closed with a total of 454 participants randomised (214 usual care/240 intervention). Other minor amendments to recruitment included updating an error to the estimated number of GP practices to be recruited, which was corrected to 36, and information about the use of Docmail used by GP practices for mailing out invitations to patients was added.
Process evaluation
Amendments were made to clarify the processes (including consent) for interviews with study participants and yoga teachers and adding that trial staff may also be interviewed. Due to the COVID-19 pandemic, it was indicated that electronic consent may be used for the interviews and class observations. Also, the option of using video conferencing for interviews was added. The number of yoga teacher interviews at pilot phase sites (4–8) and main phase sites (6–12) was stated. Stakeholders were added to the list of groups to be interviewed. The sample size of trial participant interviews was later increased to 35.
Intervention
Details were added to clarify the intervention processes, including that YTU would send participants the yoga teacher’s health questionnaires to complete before their first yoga class, and that yoga teachers would alert YTU of any AEs. Due to the COVID-19 pandemic, it was also detailed that classes would be conducted either face to face in the community or online via video conferencing. Class sizes were amended to the increased range of 8–15 participants instead of 10–15. This was due to the classes being held online. In addition, it was clarified that the GYY certification is a level 4 regulated qualification, and more detail was provided to explain what the GYY training involves and that teachers will also receive training in trial processes. A further amendment was made clarifying that the participants will be provided with advice for continuing yoga at home and in suitable yoga classes in the community that they may want to attend on a self-pay basis.
Follow-up
Due to the COVID-19 pandemic, amendments were required to follow-up processes including that the collection of follow-up questionnaire data may be done via telephone and the entry of this data would be done electronically via an online form by study investigators. It was also added that a £5 shopping voucher may be sent to participants instead of £5 cash.
Other
Additional amendments made to the protocol include detailing the sending out of regular newsletters to trial participants, the procedure for recording planned hospitalisations and elective surgery unrelated to the intervention, a statement to say that the allocation will be revealed to a participant’s GP in response to an adverse health event if necessary and to indicate that the internal pilot phase will cover the period of the two waves of courses at the pilot sites. Updates to wording throughout the protocol were also made for consistency, that is ‘instructors’ was updated to ‘teachers’.
