<![CDATA[Technology and education development are expected to make teachers easier to create and produce learning media used practically and efficiently. This study used the research development (R&D) method proposed by Borg and Gall, consisting of ten research steps. It aimed to develop a preliminary product design for a digital-based flexibility test measuring instrument. This research produces a body flexibility measurement tool for physical education subjects, particularly physical fitness. The participants of this study were Tanjung Lago 1 Public Middle School students validated, revised, and tested on small and large scales. Three experts validated this research through a questionnaire of various kinds of questions, i.e.1) an expert in sports tests and measurements, namely a lecturer at PGRI Palembang University (94% in the very compatible category), 2) an expert in electrical media from C.V. Cometronica Palembang (82% very appropriate category), and 3) the teacher of Physical education from SMPN 1 Tanjung Lago (97% very proper category). The three experts reveal that an average of 91% of the digital-based sit and reach box applied to measure flexibility tests is worthy. It is supported by the statistical results of small-scale trials with normality tests of 0.200, homogeneity tests of 0.785, and paired sample t-tests of 0.785, statistical results of large-scale trials with normality tests of 0.200, homogeneity tests of 0.64, and paired sample t-test of 0.299. This study indicates that the digital-based sit and reach box tool developed and tested for meeting validity and effectiveness can be implemented in teaching and learning activities. Key words: development, flexibility, digital.]]>
