I have seen a study where the muscle growth (of rectus femoris and vastus lateralis) were compared for (smith machine) squats vs leg extensions (see summary of the study here. One result was that the leg extension was significantly better in developing the rectus femoris than the squat.

Now there are other exercises that might on the first view lead to a similar development of the rectus femoris as the leg extension:

  • Traditional sissy squats
  • Spanish squats
  • Somersault Squats
  • Brignole Cable Squats
  • Smith Machine Hack squats/ Landmine Back Hack Squat

Maybe also some Lunge variations, Step ups or Split Squats.

So is there any data (muscle growth or EMG) which compares those movements to the leg extension? What are the results? Which exercises come close or are even better than the leg extensions for rectus femoris development? Are there exercises in the list above which I wrongly listed as candidates for this (why)?

  • May I ask why you’re looking for this info? Minuscule differences between results from these different exercises if they exist at all will vanish with training age, so why does it matter? Finding a diverse selection of exercises you enjoy will always be better that failing to adhere to the scientifically optimal selection.
    – Thomas Markov
    Mar 4, 2023 at 22:30
  • @ThomasMarkov: Just for theoretical interest to understands things better. But the differences may not be minimal as the linked study showed (before reading it I always thought that squats train the rectus femoris to a similar degree like leg extensions, but that seems so be plainly wrong).
    – Sarah
    Mar 5, 2023 at 6:44
  • I mean that over a long time course the differences are eliminated due to diminishing returns.
    – Thomas Markov
    Mar 5, 2023 at 7:09
  • @ThomasMarkov - I highly encourage pursuit of the theoretical knowledge. The more we can explore theory and current studies, the better educated our audience will be and the more experts in the field we may attract.
    – JohnP
    Mar 6, 2023 at 14:53


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.