Like other top players, Andy Murray got a well-earned break from the tennis circuit in December.
But he didn't spend the month putting his feet up and relaxing. He was working hard and going through the pain barrier in order to become a stronger and fitter player.
I spent one day on the track with him at my home in Marin County, California, and then designed a series of workouts he can use during the season.
You're probably wondering how this came about. Well, Andy's coach, Brad Gilbert, is a long-time friend and neighbour of mine.
606 DEBATE: Discuss Murray's training plan
One day I was at his house and, as often happens, he asked my advice on speed, conditioning and movement.
Brad is always looking for ways in which to do things better.
One of the great things about him is that he is very much into conditioning and hard work and understands that you've got to go out and work your butt off to reap rewards.
This particular conversation planted a seed in Brad's mind. Afterwards he talked to Andy, who was very interested in learning about how to improve his speed and conditioning.
Andy is very young and doesn't know a lot about training yet, but he wants to learn and is full of questions
We decided to go down to the track and put Andy through a workout that would test what type of natural ability he had and what he was capable of doing.
At the start of the session he did 200m intervals. This involved running within a certain time, having a short rest and then sprinting again. We did that over and over.
I was impressed with Andy's ability to run with decent form and technique.
That's rare in someone who doesn't have a track-and-field background and was a big advantage.
Andy was already in great shape, but he wasn't used to doing track training.
It was a shock to his body at first and he was really fatigued afterwards, but that was good because I knew he would be able to come back and handle the next session better.
Afterwards, I drew up some general workouts that will help Andy improve his strength and conditioning. He'll be able to do them on the track or on the road.
The aim is for him to be able to sustain his peak level of performance for longer in a match and delay fatigue.
As a top athlete competing at that level, fatigue will set in at some point. But the key is to delay it for as long as possible.
From what Brad's told me, the workouts have gone very well.
I was also impressed by Andy's maturity - it was more than I had expected.
He's very young, so he doesn't know a lot about training yet, but the advantage he has is that he wants to learn and is full of questions.
When we talked about doing a workout at the track, he wanted to know exactly how it was going to help him.
He asked me, "How is this going to help me and is it going to hurt me in any way?"
That's great because a lot of athletes go out there and train for hours without knowing exactly what they're going to gain from it.
We talked a lot about training smart and efficiently.
With all the work he's been doing, I'm certain we will see an improvement with Andy this year. And if he needs help in the future, he knows he can give me a call.