The Kiwi detailed the cramping issue during Supercars testing at Queensland Raceway today, where his Triple Eight squad was running three Gen3 Camaros.
Van Gisbergen explained that he trialled a new seat in his car during the QR test after experiencing cramping during races.
As the tallest driver in the field, van Gisbergen has been central to a number of ergonomic issues with these low-slung, compact Gen3 cars.
The front of the control chassis even had to be re-designed during the development phase last year after van Gisbergen struggled to fit in the car.
The new seat meant a new seat insert for endurance co-driver Richie Stanaway, who also cut laps in the #97 Camaro at QR today.
"We had to make a new seat because my legs keep cramping, the way you have to sit," said van Gisbergen.
"I'm sort of sitting all funky to try and get comfortable.
"[Richie has] had to make a new seat on top of that, but it seems to be a bit better for him."
Stanaway explained that this seat insert was actually the first he's used in the car, having run without any customised padding during testing at the start of the year – despite being significantly shorter than van Gisbergen.
Another focus for Stanaway today was on his left-foot braking technique in these new cars with their fly-by-wire throttles.
Left-foot braking is traditionally the less preferred practice in Supercars due to the increased fuel usage – although drivers with a heavy European background such as Stanaway still use it at times.
“It’s great to get more laps in the car," said Stanaway.
“The main thing for me was getting comfortable in the car with a proper seat insert. Because when I drove at the pre-season test in Sydney and the [test] day in February, I didn't have a seat insert.
“To be fitting into the car properly now is a good feeling, to check that off the list.
"Driving with Shane, I was a bit anxious that I'd be very compromised on my [seating] position. Luckily with the sliding pedal box in the new car, I can get exactly how I want to sit in the car. We checked that off the list.
“Another key thing is working on the blip in the throttle response, with me trying to left-foot brake. And figuring out where we go with that."
Today's test saw a number of cars and teams on track, including the debut of Triple Eight's Supercheap-backed wildcard Camaro.
Dick Johnson Racing, PremiAir Racing and Matt Stone Racing were also in action, the latter offering some hints as to potential enduro signings by giving laps to young drivers.
Kurt Kostecki and Matt Chahda both drove for PremiAir, which has a vacant slot alongside Tim Slade for the long-distance races.
Jaylyn Robotham, meanwhile, tested Cam Hill's MSR Camaro with a deal for the enduros thought to be imminent.
Down in Victoria, Brad Jones Racing opted to test its four Camaros today following yesterday's wash-out at Winton.
The four regular drivers and the recently-announced co-drivers were all in action.
