The foot bears more than 100% of your weight because it is cantilevered.
Uh, no, that’s actually the opposite of how that works. Pressure is force per area, and torque is the cross product of force and length (at right angles). The smaller the area, the higher the pressure. The smaller the foot, in this case, the harder the muscles have to work to create the same torque (or moment). #ThanksForAttendingMyPhysics101TEDTalk
jerkface@lemmy.ca 3 weeks ago
deranger@sh.itjust.works 3 weeks ago
Isn’t that backwards? A shorter lever requires less force. If you had a 10 foot long foot, you’d have to have insanely strong calf muscles to stand on your tip toes.
NocturnalMorning@lemmy.world 3 weeks ago
True, i didn’t consider the point of contact.
LustyArgonianMana@lemmy.world 3 weeks ago
This isn’t totally true (about longer limbs=harder to exercise), because it doesnt take into account how myosin works on a longer muscle/surface area, along with how electrical differences between limbs and the torso help with electrical flow due to potential energy.
Look at a thoroughbred (fastest over medium distance), an Arabian (best for endurance), a quarter horse (fastest in burst over short distance) versus a donkey (stronger pound for pound than a horse but not faster), vs a mule (stronger than horse, faster than donkey). Look at their legs. They are walking on (1) finger, look at where their ankle is. Their feet, like many animals, are angled completely differently than humans. Elephants have a similar foot to humans in that their sole contacts the ground, but obviously their feet don’t extend like ours (and they have bigger muscles). So it is interesting but I think theres more to it
deranger@sh.itjust.works 3 weeks ago
It’s totally true from a physics standpoint. A longer lever arm between the load and fulcrum requires more force to move the same weight for a type 1 lever, all else being equal.
“Harder to exercise” is poorly defined, especially when you go on to discuss endurance, speed, and force, all of which are very different terms.
I totally get what you’re saying, but I specifically narrowed it down to force for a reason. My shorter friends kick my ass in lifting due to the mechanical advantage their shorter limbs have, but I smoke them in a distance run because my longer limbs allow me to traverse a greater distance in a single step. This is complicated though because larger lungs are a factor here too.
LustyArgonianMana@lemmy.world 2 weeks ago
“All else being equal,” it’s not equal though, that’s what I’m saying. Our legs have electrical and muscular aids in them which make them unlike a lever completely.
You shortened it down to simplify a complex topic. I’m pointing out it’s not that simple and it’s okay to learn more. As we age we should keep up with learning dense subjects to keep up our neuroplastocity, and it’s a social virtue. Right now I’ve been learning about electrobiochemistry for instance. You can just download textbooks. Please stop committing to simplicity when reality is complex.
Physiology wouldn’t encapsulate a huge subject and multiple specialty fields (physiologists, occupational therapists, physical therapists, medical technologists, physical educators, surgeons, biomedical engineers) if it was simple physics. We wouldn’t need all the other muscles and junk if it was all simple physics. It’s not. It’s a highly complicated series of biochemical, magnetic, electrical, energetic, and physical properties that work against and with each other