Okay kiddo, do you know what a marathon is? It's a super long race that's about 26.2 miles long. It's really hard and takes a lot of training and practice to be able to run that far.
Now, the masters m75 marathon record is for runners who are 75 years old or older. These people are super experienced runners who have been running for a really long time.
The world record for this category has been getting better and better over the years. This means that people are getting faster and faster at running marathons even when they're 75 years old.
So basically, a long time ago, someone ran the masters m75 marathon in a certain amount of time and that became the world record for that category. But then, other people started training and practicing and they were able to run even faster, so they beat the old record.
This has happened over and over again, with different people running faster and faster times and setting new world records. It's really impressive and inspiring to see people still able to compete and achieve amazing things even when they're older.