50m freestyle training and techniques

Hi,everyone,i am new to this forum... My name is CherTeck, just learning swimming less than two years. I started train competitively three months ago. My 50m personal best is 31s. I have no coach and train myself in school's pool. I do dry land training three times per week ( medicine ball, stretch cord, ab .roller,crunches, sit up) but i don't go gym . I swim 6 times per week and each session last about 1.5 hour. I think i was born as sprinter as i don't like long distance swimming. Currently, i train freestyle only but i will swim IM during warm up. I always find the best workout for me but still cannot find the best one. But i think the folllowing mainset are good 1) 4 x100m, 4 x 75m, 4 x 50m, 4 x25m ( build to 80 % on last lap for 25m pool) 2) 25m 50 75 100 150 200 rec 200 150 100 75 50 25 m ( start from 25m then slowly increase the distance, on the way back, increase the speed) 3) 8 x 75m on 1: 15 , 20 x 50 m ( des 1-4 ) 4) Sprinting set:4 x ( 20 fast 30 slow, 30 fast 20 slow, 50m recovery, 50 m all out) 5) Speed kick: 2 x ( 1 x 100,2 x 50, 4 x25) fast kick But i always use up my energy after speed kick and cannot move on to next main set.For sprinting set, i also die in last round. For normal 50m interval swimming, i tend to swim fast and then must rest 1-2 mins . I am eager to bring my time down...i want to know what's wrong in my stroke.Why can't i swim faster despite i try very hard. Opps, i got a pair of red zoomer and a parachute. I also use them in my swimming training.I am 21 years old and hope that my 50m freestyle will hit 27s by February next year. Here are some confusion when i do the sprinting: 1) Should we pull all the way back to hips in sprinting ? 2) Should we catch the water like Popov?YouTube - Popov vs Klim 50m Perth 1998 or just pull back without high elbow? 3) i feel that the water is heavy to hug during the catch,is it the good thing because i feel my turnover will slow down by pulling back that heavy water. 4) I saw Cesar Cielo slapping his arms quickly during sprinting but Popov still maintain very nice stroke. Which is better? I would like to ask how to race 50m freestyle. Will you go all out hard during first 25m? How about the breathing frequency? i would like to try breathing at 20m and 35m in long course or 20,30,40 .Is it ok?:coffee: