very rare
Manual of Gainful Exercise
Wondrous item, very rare
This book describes fitness exercises, and its words are charged with magic. If you spend 48 hours over a period of 6 days or fewer studying the book's contents and practicing its guidelines, your Strength increases by 2, to a maximum of 30. The manual then loses its magic but regains it in a century.
Manual of Gainful Exercise is from the System Reference Document 5.2.1 (“SRD 5.2.1”) by Wizards of the Coast LLC, used under the Creative Commons Attribution 4.0 International License. Full attribution is on the Licenses & Attribution page.