You should visit your doctor before you start any fitness routine, car accident or not, and if given the “all clear” to perform physical activity, it is time to start working out!
When your fitness level is already high and you want to reach a more specific goal, like bench pressing a specific weight, reaching the goal will take more time as your body is already accustomed to working out.
No matter what shape you are in right now, a highly effective way in which you can boost your fitness levels in short time frame is HIIT (high-intensity interval training).
Aerobic capacity is improved after every single session, our muscles adapt to our new routines after every session and noticeable changes happen within the first 7 weeks of the routine.