50m Freestyle Sprint

That's a pretty aggressive goal to accomplish in just a month. Some more information would be helpful, like how old are you?, how long have you be swimming?, what does your stroke look like now? I guess it's possible that you could be a diamond-in-the-rough prodigy who just needs some tweaks to your stroke, but probably not.... FWIW: I'm 63 and started swimming again full time again in June 2015 after a 40 year layoff. I went from the mid 40's to mid 30's in about six months, but it took a lot of work, swimming 10K-15K per week, and some excellent coaching to get there. I've also found that once you eliminate the low-hanging fruit (in my case some obvious fundamental flaws in my stroke) that it gets harder and harder to improve. Not much margin of error in swimming a 50.

That's a pretty aggressive goal to accomplish in just a month. Some more information would be helpful, like how old are you?, how long have you be swimming?, what does your stroke look like now? I guess it's possible that you could be a diamond-in-the-rough prodigy who just needs some tweaks to your stroke, but probably not.... FWIW: I'm 63 and started swimming again full time again in June 2015 after a 40 year layoff. I went from the mid 40's to mid 30's in about six months, but it took a lot of work, swimming 10K-15K per week, and some excellent coaching to get there. I've also found that once you eliminate the low-hanging fruit (in my case some obvious fundamental flaws in my stroke) that it gets harder and harder to improve. Not much margin of error in swimming a 50.