Surprised that no one has talked about the following point:
1) When you mention a "low-slung" car, you should mean "low-slung" seat. Its the seat that causes the problem, not the car.
2) Most of the 'low-slung' cars indeed have low-slung seat (this means that the height between the floor and seat is very less compared to your tibia (shin bone) (
https://upload.wikimedia.org/wikiped...teral_view.png).
3) Seating on this setup compels you to keep your knees straight(er) most of the times, more so when you depress a pedal.
4) Keeping knees straight(er) stretches your hamstring muscles.
https://embed.widencdn.net/img/verit...&use=d502n&k=c.
5) This produces a pull on the pelvis, rotating it backwards (you can imagine this well if you refer the diagram above)
6) This rotation of pelvis is technically called posterior pelvic tilt (
https://s-media-cache-ak0.pinimg.com...4f4519125a.jpg)
7) This posterior pelvic tilt causes the rounding of the lower back, deviating from the natural curve of the spine, causing high stress on the individual vertebrates in the lumbar area:
https://images.squarespace-cdn.com/c...ic+sitting.jpg
8) Incidentally, if you ever do squats, the same issue causes "butt wink"
9) The only way to resolve this issue is to bring the seat closer to the pedal area so that your knees are bent sufficiently which un-stretches and relaxes the hamstrings. Also, you must consciously try to "pout your butt" by forcibly pressing your butt (but not your back) into the seat, this causes the spine muscles (erector spinae) to contract and maintain ergonomic positions (
https://i.pinimg.com/736x/fc/09/ab/f...945456695d.jpg).
10) However, the issue with this position is that it will require you to keep the right leg tibialis anterior muscle constantly contracted, because of the angle between the base of the foot and the tibia ("shin bone") needs to be held to hover your foot on accelerator, fatiguing it fast, and thus will require regular stretching (
https://www.yoganatomy.com/wp-conten...r-muscle-1.png)
11) Also, regular operations of the accelerator, brake and clutch will require more movement of the thighs (since the leg in this position will usually no longer be supported by the seat, unless you prop up using some pillows or steep under thigh angle). This will cause your ilipsoas (
https://i.pinimg.com/474x/e0/2d/95/e...5b8ac32f9a.jpg) and hip adductors (
https://www.rehabmypatient.com/media...tor_strain.jpg) of both legs to fatigue.
So then, what is the real long-term solution? Get a seat that allows you as much height as possible, get your ABC pedals adjusted so that the start position is as close to the ground as possible.
Unfortunately, most car OEMs appear to be ergonomically illiterate. You may check the heights of A/B/C pedals of your car. A and B pedals spend most of their times hardly depressed and thus should be at same elevation and as close to the floor - does your car have that? (most of the times the brake pedals is raised quite high compared to the accelerator pedal)