The research aims to explore the impact of core training accompanied by a foam roller on:

- Certain physical variables (transitional speed, agility, spinal flexibility, leg muscle power, core muscle strength, and stability).
- The level of rotational performance.
- The digital performance level of junior swimmers in the 100m butterfly stroke.

The researchers used the experimental approach, as it is suitable for implementing the research and its procedures. They applied a pretest-posttest experimental design with two groups: an experimental group and a control group. The research sample was intentionally selected from swimmers at the Benha Sports Youth Center, with a total sample size of 25 swimmers. Five swimmers were excluded for conducting a pilot study, leaving a primary sample of 20 swimmers, divided equally into an experimental group and a control group.

The researchers reached the following findings:

- There were statistically significant differences between the pre- and post-measurements for the experimental group across all physical tests, the digital level of rotation, and the 100m butterfly swimming performance, in favor of the post-measurements. Improvement rates ranged from 1.13% in the digital performance of the 100m butterfly to 14.79% in the core strength and stability test.

- Statistically significant differences were observed between the pre- and post-measurements for the control group in the 30m sprint test from a high start, the bridge test, the digital level of rotation, and the 100m butterfly swimming performance. Improvement rates ranged from 0.10% in the digital performance of the 100m butterfly to 4.90% in the core strength and stability test.

- Statistically significant differences were found between the post-measurements of the experimental and control groups in all physical tests, the digital level of rotation, and the 100m butterfly swimming performance, favoring the post-measurement results of the experimental group.