“…Regrettably, as far as we know research studies examining the effect of flexibility detraining are really scarce and contradictory (Cipriani, Terry, Haines, Tabibnia, & Lyssanova, 2012;Rancour, Holmes, & Cipriani, 2009;Willy, Kyle, Moore, & Chleboun, 2001), especially among school-age children Merino-Marban, et al, 2015). While several previous studies showed that, after a shortterm stretching program, individuals' flexibility levels reverted to their baseline after 4-5 weeks of detraining Willy, et al, 2001), other research studies found that individuals retained significant gains (Cipriani, et al, 2012;Mayorga-Vega, et al, 2014b;Rancour, et al, 2009). PE teachers must also face other planning-related problems when intending to develop students' flexibility levels .…”