The most common though that I see in BJJ is the cervical sprain or strain. The cervical spine is the most mobile segment of the spine however it puts it at a high risk of injury. Cervical sprains/strains are soft tissue injuries. A strain is linked to muscle, while a sprain is linked to tendons.
However, for some people, effects are much shorter and they have to take modafinil 2X per day (albeit this is not that common). For other people, effects can last 20-24 hours. It all depends on how your body processes it.
Food has no effect on overall modafinil bioavailability; however, time to reach peak concentration (t max) may be delayed by approximately one hour if taken with food. Distribution Modafinil has an apparent volume of distribution of approximately 0.9 L/kg.