The purpose of the study was to compare the influences of a training programme's instructional delivery method (synchronous and asynchronous) on Greek in-service physical educators' cognitive understanding on student assessment. Forty nine participants were randomly divided into synchronous, asynchronous, and control group. The experimental groups participated in the same training programme with different online instructional method. The control group received no intervention. A 17-item questionnaire was completed before and after programme implementation by the entire sample. A two-way analysis of variance with repeated measures on the last factor was used for data analysis. The methods x measures interaction effect were significant. Both experimental groups, unlike the control, presented a similar significant increase in their understanding. Conclusively, synchronous and asynchronous instructional approaches of a training programme enhance equally Greek physical educators' cognitive understanding. (Contains 1 table and 1 figure.)