The relentless toil of pre-season training has been even harder this year for Carlos Sainz as he undergoes "arguably the toughest winter of my life" as he prepares for the faster, harder to drive results of the regulation changes for 2017… for more speed means greater physical strength is required.

"Indeed, they will be harder to drive," says the Spaniard, "so the training we've been doing up to late last season won't be useful. We now must go some extra miles so to speak."

The greater muscle mass for Sainz has meant greater weight - in his case a four kilogram rise to 70kgs from the end of the 2016 season. And the "extra miles" he speaks of relate to marathon cross-fit sessions.

"Instead of the usual 50 minutes, we now do between 90 and 120 minutes, the same as a grand prix," he reveals. "Thus, I work out for longer times at around 180-190 beats per minute. I also include boxing and cardio work in those sessions, which all in all means I work my physical endurance way more by doing stuff all the time."

The hard work also translates to the swimming pool, where he will undergo sessions of an hour, sometimes longer.

All the winter's hard work is overseen by one of Toro Rosso's trainers with the focus predominantly on increasing both Sainz's shoulder strength but also neck strength.

"We work out the neck in two ways," he explained. "Firstly, we pull and hold weights with it in the gym, which is very similar to what we will do on the track - resisting g-forces, that is - and secondly we are doing specific go-karting, which I do two or three times a week."

On the kart track, Sainz wears a helmet designed specifically with greater ballast in certain areas to help strengthen the neck.

"Those weights make my helmet around 1.5 to two kilos [3.3 to 4.4 pounds] heavier, which translates into similar g-forces I'll have to stand in my F1 car," he added. "That is just one of a complete set of exercises I'm doing to work my neck fitness to the full."

Some exercises can be a sight for sore eyes, it not uncommon for Sainz to be found in the gym with a thick rubber belt around his helmet as he stretches for long periods of time.

The acid test over his winter training will come at the Circuit de Catalunya later this month for the first of the winter tests, and there is an argument he could be in better shape than most.

"On the one hand, I believe you get to the best physical form of your life when you're 21 or 22 years old, and that could be good," he said. "But on the other hand, some drivers like Fernando Alonso, Lewis Hamilton and Kimi Raikkonen have already experienced in 2005, 2006 and 2007 the kind of g-forces we will have this year."