This research aims to develop educational units based on inverse education using the application of WhatsApp and know its impact on the level of technical performance in swimming crawl on the back and cognitive achievement, the researcher used the experimental method by following the experimental design of two groups, one experimental and the other control, on a sample of (80) students of the second year of the Faculty of Physical Education for Girls - Zagazig University Conclusions: 1- Reverse teaching method using Whatsapp has a positive impact on learning to swim crawl on the back (under research) and cognitive achievement. 2- The traditional method (orders) followed contributed in a positive way in learning to swim crawling on the back (under research) and cognitive achievement. 3- The experimental group which used the inverse learning method using whatsapp advanced the control group which used the traditional method (verbal explanation and performance of the practical model) in learning to crawl back (under research) and cognitive achievement Recommendations: 1- the need to apply the method of inverse education using whatsapp because of its effectiveness in learning and mastery of the cognitive and skillful in swimming crawl on the back to the students of the second year of the Faculty of Physical Education Girls - Zagazig University. 2- Encourage teachers to use modern techniques in their teaching, especially the application of Whatsapp on mobile phone, because of the positive impact in the development of students' attitudes towards learning to swim. 3- Holding courses and workshops for faculty members and their assistants and students for training in reverse education before its implementation