Final answer:
Andy Murray started tying a lucky charm to his tennis shoes in 2015.
Step-by-step explanation:
In 2015, Andy Murray started tying a lucky charm to his tennis shoes. This is an object that is believed to bring good luck. It could be a small trinket, a talisman, or even a token with sentimental value. Tying a lucky charm to his shoes may have been a personal superstition or ritual that helped Murray feel more confident and focused during his matches.