“…Thirteen studies (Ludewig and Borstad, 2003;Walther et al, 2004;Giombini et al, 2006;Kachingwe et al, 2008;Lombardi et al, 2008;Engebretsen et al, 2009Engebretsen et al, , 2011Østerås et al, 2009Baskurt et al, 2011;Calis et al, 2011;Yiasemides et al, 2011;Martins and Marziale, 2012;Kromer et al, 2013;Littlewood et al, 2014a) adequately reported the frequency of undertaking the exercise. Of the eight studies that evaluated largely home-based exercise programmes (Ludewig and Borstad, 2003;Walther et al, 2004;Giombini et al, 2006;Kachingwe et al, 2008;Engebretsen et al, 2009Engebretsen et al, , 2011Yiasemides et al, 2011;Kromer et al, 2013;Littlewood et al, 2014a), three (Kachingwe et al, 2008;Engebretsen et al, 2009Engebretsen et al, , 2011Yiasemides et al, 2011) used daily exercise; two (Giombini et al, 2006;Littlewood et al, 2014a) used twice daily exercise; one (Kromer et al, 2013) commenced with twice daily exercise and gradually reduced frequency over time; one (Walther et al, 2004) used a minimum of five exercise sessions per week; one (Ludewig and Borstad, 2003) used three exercise sessions per week.…”