Let me get this out of the way, first. 5'7" isn't that short. Certainly not so short you need a unique approach to swimming. Don't let yourself use your height, or perceived lack thereof, as an excuse to discount coaching/technique advice. I've rarely seen stroke advice that was good for someone 6' that wouldn't be good for someone 5'7".
Now that I've addressed that, let's go to your current speed vs. your goal. A 1:09 100m isn't bad. Pretty good, actually. How frequently are you swimming? What are your workouts like? You may be a 1:45/100 long distance swimmer because your stroke is bad, or maybe you're not training for that. My thought is it has to be some of the latter, because to swim a 1:09 100, you have to be doing a lot right. Regardless, it doesn't matter much what your 800 speed is.
Getting to 1:05 in the 100 from where you are is a simple math problem. You either need to increase your stroke rate ~8%, increase your distance per stroke ~8%, or some combination of the two.* TI is a great resource to help improve your technique and therefore your DPS. But any adjustments need to be considered against the affect on stroke rate.
Search this forum for "USRPT" or Ultra Short Race Pace Training. I've used it with great success to train for competitions. It seems tailor-made for your very specific objective. Long story short, for the 100 free, it entails swimming lots of 25's at 100 "Race Pace" on short rest.
*There are other technical things you can do to improve your 100 time. Specifically, there's likely time to be gained just with better starts and turns.
Last edited by gary p : 06-15-2018 at 03:06 PM.