It seems like the Starting Strength program lacks any sort of stretching routines. Should any form of stretching be done after the workouts or on your off days? Or is it completely unnecessary for the program?
Would adding a yoga session on an off day be detrimental to your progress?
Anything more strenuous than a long hike is detrimental to totally orthodox, full-focus-on-strength-and-size Starting Strength. However, I've found that daily (or less frequent) yoga is a great supplement to powerlifting.
If you're capable of all the exercises in the program, there's no particular need for additional stretching. I've found that the exercises themselves provide a moderate degree of mobility work. I've also found that many people, particularly the un-athletic, are incapable of performing at least one of the lifts without specific stretching, mobility work, and copious warm-up.
Actually I've heard that stretching before a workout might be counter productive, since the stretch will decrease your ability to beat your own max load. You should focus more on a full body warm up.
I normal go for 7 minutes on the elliptical or rowing machine (full body) or just start with a combo-set of no weight barbell exercises.
After finishing a workout I do stretch adding also some yoga poses.
Dynamic warmups are essential to get those muscles going and avoid injury, things like bodyweight lunges, pushups, light weight KB/med ball movements will get the blood flowing, and as long as you are doing these types of movements to the limits of your movements you will not have a problem. Yoga is a great tool, but because its focused on creating long lean muscle it will not help you to make stronger muscle, but it can help your recovery as long as it is used in moderation.
