Not sure if this is necessary for Illustrious.

for Pony/SD1.5: https://civitai.com/models/112135/anti-long-torsolegs-or-sdxlsd15-lora

recommended weights @ WAI v14.0 with ComfyUI : -1 ~ 1

If you want to shorten the torso, set lora weights positive value.

If you want a longer torso, set lora weights negative value.

This LoRA is powerless against the phenomenon of torso elongation with latent hires-fix.