Lever systems in the human body
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- Опубліковано 7 чер 2024
- After watching this video session, it is expected that you will be able to
Define levers.
Enumerate the main uses of levers
Identify the three classes of levers
Give mechanical examples of each class of levers
Compare the mechanical advantage of the three classes of levers
Give anatomical examples of each class of levers
Explain why the second-class lever at the ankle joint is the most suitable for its function.
Discuss the fact that third-class levers are the most common in the body
0:00 Introduction
0:05 Definition and Uses of Levers
1:44 Types of levers
1:55 First-class levers
3:03 First class levers anatomical example
3:33 Second-class levers
4:29 Second class levers Anatomical example
5:10 Third-class levers
5:50 Third-class levers anatomical example
Presented and edited by Dr. Akram Jaffar (Ph.D.).
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LOVE this video! Great in-depth explanation along with helpful visuals and straight to the point!
Great video very helpful, thank you!
Thank you Dr Jaffar for your very clear explanation of the 3 lever types. Much appreciated.
+Shaya Dubin Thank you and best wishes!
Really helpful, thank you.
Thank you for the video , much appreciated
Best description of what the differences between class levers. Thanks you
-Therapist
+Rodney Marquez Thanks!
This is a very illuminating video, thank you
Thank a lot Dr.Akram
I really appreciate your simple and effective explanation
Very solid video, thank you Doctor Jaffar.
Thank you so much Dr. This was the best and easiest definition of any lever
Thanks for this video. The clarity of these examples are excellent
really good description now i feel ready to identify levers in the body
thank you oh so very much Dr. Akram Jaffar!!
wow very understandable, again thank you a million.
+Oscar Pena You are welcome. Best wishes!
Thanks for your video 😊😊
I just started learning this topic in biomechanics, this was very helpful
Glad it was helpful!
Great Video! Thank you!
thanks a lot Dr. it was very helpful and i was trying to know lever class used on knee and ankle which the exact examples you included :)
Thanks for this amazing video.
this was amazing. thank you so much!
Thank so much for your vedio I'm from tamilnadu
could someone please correct me if i am wrong? at 2:38, the video says Mechanical advantage > 1 but according to the formula given of Force arm/Resistance arm, or 50kg/100kg, the result would be 0.5 which is not >1.
similarly, the video also says Mechanical advantage < 1 , but Force arm/Resistance arm yields a result of 2, which is not
excellent explanation, great job Dr Jaffar
That was great. Thank you!
fab video - thanks
جزاكم الله خيرا
10 years later and this video is still fantastic! Great explanations:) Thank you!
Glad it was helpful!
Facts are always facts unless shown not to be facts. That's a fact. Words of wisdom from a physics professor involved with the Physics of Sports.
I wonder if the example of a hammer is not also partly a type 1 lever: thinking of the lever along the direction of the handle, with the fulcrum in the middle, and the nail the weight at the end. We can see evidence for this point of view in that the length of the handle certainly affects the effectiveness of the hammer over-all. Thanks for the nice video!
One other comment: To contract more than a few cm is impossible by a muscle. Muscles simply do not work that way. So the body has to resort to third kind levers to get a limb to travel a bigger distance.
Great video, but you are correct. The claw hammer is a first class lever.
Bed
@@ReneGrothmann yeah most places in the body apart from the back of the jaw, the muscle is strong but only moving a short distance. Leg muscles are probably producing the weight of half a car or so over 3 inches to lift your body 1-2 feet.
Thank you very much ❤!!
helpful, thanks!
that was very helpful
best classification ever
Best video ever
Thank you, come again
الله يباركلك :)
To your last point, I remember calculating the tension on the back muscles required to lift a certain weight during a dead lift. I was shocked at the results.
What was the result?
good information...
Thank you for posting your lecture. Would your head example at 3:32 also be a 2nd class lever when the muscle force and resistive force act on the same side of the fulcrum (lower part of the head) to tilt the head backwards?
An example of how it could be technically applicable (and I realize this is a little specialized, but it works) would be if you are hanging upside down. If you try to lift your head "up" in either direction (think flexion or extension of the cervical spine). Gravity will try to pull your skull back toward the neutral position you started in, and it will act on the SAME side of the joint that's moving as the muscle that's doing the work. Put another way, the cervical extensors will try to extend the cervical spine by pulling on the posterior side of it, and the weight of your head (the resistance) will try pull it back into flexion, and that force of gravity will also be posterior to the joints in question.
Interestingly, whether the muscle action in this scenario is characterized as a 2nd or 3rd class lever will depend on how far from neutral your head goes. The muscle might start as a 2nd class lever (having a greater moment arm/mechanical advantage than the resistance) and eventually switch places as the head, and thus its weight, gets farther away from neutral. Hope that makes sense.
Thanq sir for your good and clear explanation i have clarified my doubts
+Baji Dheeraj
You are welcome!
Thank yuou so so much, this was helpful
You're so welcome!
Thank you sir.......👌
Most welcome
Thankyou so much. ❤️
Welcome!
wow u r a great doctor👍 thanks a lot👌and keep going please💐💐
+Tabark Faiz Best wishes
+Human Anatomy Education ur welcome 💐💐
Thank You!
You're welcome!
Helpful thank u
How do you make these videos. I was thinking to try it for my school presentation.
it was so helpful ^_^
this helpful to me I'm at school btw. lol
Hello. I like your explanations of levers in the human body. I have one question. How would I be able to calculate the force required to move objects? Is there formula? I am curious because I am interested in figuring out stuff like how much pounds of force is required during something like a push up. I want to know how much pounds I am moving when I do a push up and what lever is being acted on. Thanks in advance, as well as to any other youtuber that would like to help me.
Nice explaination but we need formula of those classes and can be derived!
But why do the muscles need to move a shorter distances in the third kind of lever systems ?
Since Work is defined as Force times Distance, the higher Force neccistates less Distance for the same amount of Work
When the entire hammer with hand applying force us included in the example of the hammer pulling out the nail, it is an example of a first class lever, and thus, per the first class lever mechanics, the required force applied by the hand to pull out the nail is reduced with length of hammer handle.
Good explanation, thank you
You are welcome!
Thanks :)
Sorry but a small corretion a clawhummer nail system is a second class lever. The resistance hand or load is the nail but the force hand is actually the handle of the hammer , it moves a greater distance compared to the nail, hence delevering a higher force.
Correct. I noticed this as well, I think it might be the only mistake in the video.
Close, but not quite. You are right that he made a mistake, but you also have made one. A claw hammer - nail system is not a second-class lever, but in fact a first-class one. Because the pivot point - the head of the Hammer - 6 between the effort arm, the handle of the hammer, and the resistance arm, the nail. It's a little bit confusing, because the lever is at a 90-degree angle, instead of being a straight line, but the same principle still applies.
thank you
Thank you :)
Best wishes
Awesome vid
Thank you!
very helpful
Glad to hear that
Hello sir🙏
Which type of lever is most effective in sports movement??
Depends
Watch Amazing Facts about the Human Body
Best explained
Glad you liked it
He is my doctor in my medical school 😄
I love this
Thanks!
Thanku buddy ,
nice video
Thank you!
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The muscles that extend the foot are actually on a first class lever system. The toes are not the fulcrum but the load and the ankle is the fulcrum. If the soleus and gastrocnemius were attached to a ceiling hoist, it would qualify as a second class lever, but because they are attached to the, but because they are attached to the back of the tibia near the knee joint (actually the gastrocnemius is attached to the bottom of the back of the femur so plays some role in bending the leg if not countered by the quadriceps), they anchor to the moving fulcrum. It's easier to visualise this lever as pushing the floor down rather than lifting the body up.
Practically the only second class lever in the body might be biting with the very back wisdom teeth, depending upon the insertion point of the massetter this could either be second class or very slightly third class or just direct in line with the muscle.
Maxim Fit , it should be, but how could this be technically applicable?
Finally got the concept lol 🙆
Tysm❤
Thanks!
yeet gcse pe tomorrow #gcse2019
دكتور فراس ❤️ عرفتك من صوتك 💁🏼
شكرا على الشرح
???
Human Anatomy Education دكتور فراس انته مو ؟؟؟
+noor muh No I am not.
Ycan you do an arabic version
Ha bibi habibi Rafal
#india
Wheel and axle is also called a continuous lever, why?
Te pusiste la 10 capo
The triceps is also a 1st class lever.
1 class level's mechanical advantage can be =1 as well
Explained in plain English.
লিভার আমাদের সুস্থ রাখে
Why the body has mostly 3rd type levers?
Minimum shortening of muscle results in wider range of movement.
And why not 1st type levers? Can you also give an example of 3rd type levers in everyday life?
Dr akram are you from kurdistan
I live in Canada after I left Iraq long ago, but I am not originally from Kurdistan with due respect to Kurds. Thanks for your interest in the channel.
finally a video that i can use to cheat
I love you 🤣
Best wishes!
U confused me more !
WTF!!!!
you say body-- 'buddy' wtf!🤔😂😂