[1] Univ Ulster, Hlth & Rehabil Sci Res Inst, Sch Hlth Sci, Newtownabbey BT37 0QB, Antrim, North Ireland
[2] Belfast Hlth & Social Care Trust, Physiotherapy Dept, Belfast, Antrim, North Ireland
[3] Belfast Hlth & Social Care Trust, Royal Hosp, Clin Res Support Ctr, Belfast, Antrim, North Ireland
[4] Queens Univ Belfast, Resp Med Grp, Ctr Infect & Immunol, Belfast, Antrim, North Ireland
[5] Belfast Hlth & Social Care Trust, Belfast City Hosp, Belfast, Antrim, North Ireland