Biomechanics and Muscle Leverage | CSCS Chapter 2
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- เผยแพร่เมื่อ 23 ก.ค. 2024
- CSCS Chapter Study Guides & More: / drjacobgoodin
In this video we'll learn what biomechanics is and talk about three different kinds of muscle leverage: class 1, class 2, and class 3 levers along with examples of each. This content comes from Essentials of Strength Training and Conditioning Chapter 2 published by the NSCA.
Get certified as a CSCS (Certified Strength and Conditioning Specialist). This lecture is part of a comprehensive and ever-growing video series covering topics related to strength training and conditioning: bit.ly/3tOJp5s
TIME-STAMPS
00:00 - Intro
01:00 - Biomechanics Definitions
01:35 - Skeletal Musculature
02:45 - Key Terms
05:15 - Levers
08:10 - Mechanical Advantage
09:03 - First-Class Lever
10:44 - Second-Class Lever
12:20 - Third Class Lever
13:05 - Patella
14:15 - Mechanical Advantage Changes
15:45 - Moment Arm
16:37 - Mechanical Disadvantage
17:44 - Where to Head Next
RESOURCES MENTIONED
Haff, G. G., & Triplett, N. T. (2015). Essentials of strength training and conditioning 4th edition. Human kinetics.
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Disclaimer: This video does not have any affiliation with, or any recognition, sponsorship, or
endorsement by, the NSCA. CSCS® and Certified Strength and Conditioning Specialist® are registered trademarks of the National Strength and Conditioning Association.
#CSCS #NSCA #DrGoodin
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Fellow strength specialists, thanks for checking out this video-it’s part of a playlist that dives into the major topics from the NSCA’s Essentials of Strength Training and Conditioning. I create these lectures for my strength and conditioning university students but hope that they bring value to you as well. More here: bit.ly/3tOJp5s
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Dr. Jacob Goodin is a professor of kinesiology at Point Loma Nazarene University (PLNU), and holds a PhD in Sport Physiology and Performance from East Tennessee State University. He has over a decade of experience as a strength and conditioning coach and sport scientist from the high school to NCAA Division I levels. In addition to his role as a professor and research mentor, Dr. Goodin directs the Athlete Monitoring Initiative at PLNU, which provides testing and monitoring services to over 200 athletes yearly as well as research opportunities for kinesiology students.
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Having the pictures of the muscles along with the descriptions of different classes of levers helped a lot. Thank you!
THANK YOU SO MUCH for these instructional videos. Absolutely great dissection of relatively complex topics!
Biomechanics seems like a very intimidating subject but i'm glad I can come back to these videos. I will definitely be going over the levers again but your video was a much better way of learning this matter rather than the textbook.
I liked how you gave examples of specific exercises for each of the levers because it helped me visualize between which muscles are resisting and operating when doing the movement. Great video!
This really helped me understand the different classes of levers and it makes sense now! Thank you
Sometimes just hearing it isn't enough. The visuals WITH the explanations help so much!
Such a good refresher from the biomechanics class I was able to take with Professor Aguinaldo this past semester! Seeing these visuals always helps me better understand how our body works.
I really liked learning these different levers and how it affects mechanical advantage. The images were a big help especially understanding (M) values.
This was a great refresher on biomechanics! This topic has always been complex and a little difficult for me to grasp, but the explanations were so helpful!
I absolutely loved that you included the example regarding the patella's role for quad levers. So interesting to think about how intricately were are designed and how something so "small" really plays a huge part in affecting our mechanical advantage and also allows us to move better!
I really appreciated the different examples for each of the classes of levers. They were all blending together in my mind but the examples helped me understand the differences between each of them.
This was a really helpful summer of levers! I always get confused on the different classes of levers, but this was straightforward!
I'm a new grad PT starting to study for the CSCS, and this is a fantastic overview of my first year biomechanics basics, thanks for the great info Dr. Goodin!
Awesome video for those not only studying for the CSCS but also for general knowledge. Very helpful!
Interesting to learn about how force relates to muscular movement! Excited to learn more about this in Biomechanics this semester.
The examples you gave throughout the presentation really helped to clarify levers for me.
This was a great review of biomechanics. You explain concepts in a way that just makes so much sense.
Thanks for the explanation of the levers, It was nice to review because I had struggled with this in biomechanics
The way that you broke down the different levers was very helpful to me! I was a little confused regarding the chapter in the textbook but the way you described it, along with the visuals was very helpful to me.
I appreciate the biomechanics refresher!
Really loved learning about the patella. As an athlete that deals with patellar tendoinits, it was interesting learning more about what goes on and how it works.
Stupendous video Jacob!
Biomechanics was a class I struggled to remember terms and concepts. Having an overview, especially on the three different levers really helped.
Learning about muscle leverage through the textbook was tricky for me because I was unable to picture it in my head. However, your demonstration of what a lever is with your pen was extremely helpful. Thank you!!
it is super cool to learn about how to leverage our bodies in different ways in order to maximize our lifts!
All the visuals provided help a lot when I'm trying to understand difficult topics. Trying to understand First-Class Levers was somewhat challenging and the visual makes everything connect
Really liked the diagrams and subsequent explanations you gave. Made it easier to picture the muscles moving and skeleture movements associated with it.
All of this information was so interesting! One fact that stood out to me was how our tendons are subject to more force than that force that is externally exerted by our hands or feet. Shows how intricate our skeletal musculature is.
This video does a really good job at explaining the three different levers. Thank you!
Have you ever thought of applying this to bodybuilding training, in example finding the best exercises for muscle growth biomechanically like Doug brignole has done?
Every serious strength trainee needs to buy Doug's book 'The Physics of Resistance Exercise' - best investment you'll make!
@@nelacostabianco what kind of results did you get with it?
@@joojotin Doug's exercise biomechanics insights are revolutionary. Better results with less time. Ex. Doug's 'early phase loading' principle helps eliminate useless exercises when you understand that there is a correlation between the strength curve of the muscle and the resistance curve of the exercise. So choosing the best exercises is key for better results.
@@nelacostabianco absolutely agree
Learning about the mechanical advantages was really interesting to me because I had never learned that there are certain movements in which our muscles have an advantage, which makes it easier for us to lift more weight.
Hearing the explanation of the different levers really helps me grasp how each works.
This video provided a great reminder about the three different levers and how they compare to each other. I also appreciate the examples and explanation you provided for each one. The biomechanics of strength training is very interesting to me so I enjoyed this video.
Really helpful video and the relativity to the strength aspect of it made it easier to understand.
I enjoyed learning about the three classes of levers. The figures provided were very useful to helping me understand each better.
Learning about the three classes of levers was absolutely fascinating and the functions of them as well
It is super interesting how even though it is shown that we produce a certain amount of force, we are actually producing even more due to the considerable mechanical disadvantages of our muscles.
Taking a lot of notes and digesting a lot of these concepts, thoroughly. Not perfect nor an expert but definitely believe I am learning greatly.
The photos really helped get a better grasp on what a moment arm is, after just reading the chapter.
I am feeling ready for the quizz tomorrow !
I always had trouble grasping the concept of muscle leverages and moment arms. This video helped me gain more understanding of both of these topics!
The wheelbarrow example really helped me understand exactly what creates leverage. I also think it’s really cool that we can determine whether a muscle is at a mechanical advantage or disadvantage based on whether the equation AF/RF comes out to a number lower or higher than one.
I like how you explained mechanical advantage with drawings because it helped me visual what is taking place! Thank you!
This was a very helpful video. I was a little confused with the levers, but the wheelbarrow analogy perfectly clarified it. Thank you!
The bicep curl example of a lever disadvantage helped me understand the concept because of how you explained the distance from the origin and where the weight is being lifted from.
Thank you so much for the video and information given. I am a visual learner so watching this video gave me better understanding opposed to reading info straight from the text
It is interesting to dive into the physics and mechanics of muscle movement how muscles pull at certain angles to create force and where those forces are being applied. It was also interesting to see which joints were associated with each type of lever.
Amazing man, so much more clear!
It was really interesting to learn about the concepts of levers and how the forces that levers produce apply to different parts of the body.
I admit doc, you have inspired me to study more...its cool how articulate everything related to your craft
I think the use of a force plate is so interesting to measure force and contact! Hope we get to see that in this class or in other classes!
Just wanna give you a big thank you! Passed the Science portion because of you.
The three different types of levers are very confusing however, the diagrams and definitions helped me to better understand each of them. I also find it crazy that people have the potential to have an advantage when it comes to weight lifitng based on their body structure and moment arms.
Learning about all of the different forces that are used by the muscles was a very interesting topic especially with how levers were talked about.
I learned a lot about the components of the lever since that section was more difficult for me to understand. I really liked the wheelbarrow analogy for the second class lever. Thanks for the help!
Well explained as usual❤️
The mechanical advantage part was really interesting to hear. I can see some parallels with the training videos at my work that teach us how to lift heavy objects easier.
I've never studied muscles and exercise from a biomechanics point of view and this was very interesting!
*biomechanical haha
The breakdown of the three lever classes helped clarify some of the things I found confusing. It is also fascinating how much of our skeletal muscle operates at a mechanical disadvantage.
I'm slowly turning from a gym rat to a biomechanics expert. Thank you for this golden information.
The wheel barrow example was awesome to remember the second class lever by!
P.S. I will now squat and occasionally envision the patella's movement giving me power.
I had not known the difference between each lever class before watching this video.
Of all my years in anatomy I did not realize how crucial the patella actually is. Being a anchor for the quads as well as creating distance of the quadriceps tendon form the axis of rotation.
Biomechanics was always a hard subject for me, but the examples that you gave, like the wheelbarrow, were helpful in painting the picture more clearly.
I thought the breakdown of mechanical advantages and disadvantages was super helpful. Understanding how crucial the moment arm plays in the two factors makes a tremendous difference.
nice video Dr. G!
Wow, I never realized that the knee cap was more than just a bony pad to stop the tendon from rubbing on the bone! I always thought it was simply to reduce friction, but it also acts as a psuedo-pulley to increase the amount of force that is translated from the quadriceps, making the system just a little more efficient. The human body really is amazing.
Mine is also a percussion instrument thanks to all the cracking and popping from years of running!
This really helped me understand levers better. It's crazy to think that most of our musculature is operating at a mechanical disadvantage. I found it interesting that when we test athletes' foot contact on force plates, the force shown is that produced by the feet however, what's not shown is the force that our musculature had to overcome because its operating at a mechanical disadvantage.
I learned about the different types of levers and I really appreciated the examples for each. I was surprised to know that most of the skeletal muscles operate at a mechanical disadvantage.
Thank you for doing these videos! Make studying for the CSCS test a lot easier
It was interesting to learn about the differences between first, second, and third class levers.
In this video, I learned about the biomechanics of the three different types of levers, while also applying those concepts to mechanical advantages and disadvantages.
The mechanical advantage of the patella was interesting to learn about and how it maintains the distance from the quadriceps tendon and the axis of rotation of the knee.
Biomechanics has always been confusing for me to grasp, but this video was helpful in recapping mechanical advantages and the lever system.
The three types of levers and how they effect force output was very interesting to learn about. I was shocked to hear that it takes 8x the force of the weight when working your triceps.
It is so crazy how you've done 1,000 bicep curls today! Lol. I never thought how the pronator teres muscle could be a synergist to a biceps curl because they seem like completely unrelated muscles. However after you explain it, it makes so much sense! Thanks for helping me think outside the box.
haha I was just doing my best Anchor Man impression. My biceps tendon feels inflamed just thinking about doing 1000 curls in a day...
Great topic: what would the class lever for a back squat be? Would the axis be the hip joint? Would the torso and the femur be considered the arms? There’s two reasons for these questions. 1. If the hip is the axis and the bar sits on the upper back while moving eccentricity(resistance) the force(weighted barbell) really isn’t on the posterior side of the axis. It’s sits just over the hips or possibly a little on the anterior side. 2. If a person is tall (6’6 or taller) they most likely have a long torso, femur and tibia bone which makes it a little harder to keep the bar over center of mass. PS I’m currently taking Kinesiology 😊
I found the segment on the patella and its affect of leverage advantage very interesting. I had no idea it was optimal to have a patella for leverage.
It was really interesting to me how you highlighted the patella and its unique mechanical advantage. I also didn't realize that that our muscles frequently operate at a disadvantage mechanically???
So cool with 2nd class levers like the ankle that the calves and soleus can lift our whole bodies due to the mechanical advantage, even though they are relatively smaller muscles.
I thought the difference between the different classes of the lever classes were really interesting, and definitely something that I had not learned before.
Great video Great workout Great channel Great content Great athlete Great motivation and inspiration keep doing what your doing and I Will always support you and your channel and thanks for the upload
Thank you so much. Will do!
Pronator teres is also a flexor of the elbow joint. I would argue that pronator teres is best described as an agonist during elbow flexion. If one focused on supination during elbow flexion, either dynamically or isometrically, then I would argue pronator teres is best described as a synergist. There is definitely some inherent ambiguity in muscle classification depending on the details of any given movement.
I found it super interesting that most of the skeletal muscles in the body operate at considerable mechanical disadvantages. I don't know why, but I kind of assumed that most muscles were working in advantageous conditions.
I don't know who would give a dislike for such an informative video for free. Must have been the bicep joke.
These videos are absolutely brilliant!! Very informative and immersive😀. They are really helping my studying, thank you😀.
Do you do any audio blogs?
Thanks Lee! Working on getting a podcast going sometime this year. I'll announce it here when I do
I had never heard of a first class lever but now the next time I go to a gym and do tricep extensions I will understand what is happening.
A one to eight mechanical disadvantage for triceps is crazy! I never thought about the physics of different joints. Give me a long enough lever and a fulcrum which I can place it and I can move the world I guess :p
I thought the comparison between the second class leaver and a wheel barrier made much more sense on the reason for there being a mechanics advantage behind the muscle movement. The reading was difficult for me to follow, this video helped clarify things for me.
Hi Dr. Jacob. Congratulations, this video was amazing. Please, could you inform the reference (book or article) from the pitcures?
The three different levers were very interesting, but got a little confused when comparing a 2nd class to a 3rd class lever. In addition, I found the mechanical disadvantage slide very interesting and was comparing what we learned to movements we see commonly in sports such as jumping and running.
Can you make a video on how muscles change shape and lever arms when moved over other joints?
Little interesting tidbit in practice: If your family tends to have muscles that attach further out on the skeleton than is considered quote on quote normal, everyone in said family is an absolute monster in terms of strength
Are there any other ways to directly test to amount of mechanical stress put on muscles and tendons besides a force plate? It is weird to think your muscles are for the most part at a constant disadvantage but are still able to overcome that and recover during sports.
hi dr.goodin nice shirt like the check mark lol. But I didn't though there was so many different levers in the body although it would makes sense because every body part is different lengths.
I have messed up with the angle of pull , they say when the angle 90° there is rotatory force, >90 dislocation ... could you plz explain that point ? Thank you
Just a question: If you looked at where the tendon of the Triceps inserts, would that not make it a third class lever?
Thank you for the video. As far as I understand, triceps extension is the 1st class level because the triceps is located on the opposite side of the fulcrum relatively to the resistance. However, leg extension is the 3rd class level because the rectus femoris insertion is anterior side of the tibia which is in between the fulcrum and the resistance. Why for triceps extension, we look at where the triceps is located (posterior to the humerus) not on its insertion (posterior to the ulna, which on the same side as the resistance relatively to the fulcrum in triceps extension) but for leg extension we look at the rectus femoris insertion which is the tibia? Thank you
When looking at force production and also programming in general. How do you use this concept in exercise selection? Isometric, eccentrics for example and when to use them?
Yeah good question George. Sometimes it might affect your selection based on muscle contraction type like you say. More often in my coaching though I'm thinking about the force requirements of the sport and then doing my best to overload or at least match those demands in the training. Would love to go more in depth in future videos on that topic
@@DrJacobGoodin A future video covering some applications would be great! Thank you for your response, that actually makes perfect sense when applying specificity of training. Thanks!
Regarding the gastrocnemius and soleus acting at the ankle joint, this does not constitute a second class lever. I know variations of this diagram are in virtually every biomechanics and physical therapy book, but they are wrong. The axis about which there is a tug of war between body weight and the gastrocnemius is the ankle joint, not the fulcrum between the ball of the foot and body weight. If the overall line of gravity of body weight was centered over the ankle, the person would be falling over backward. If the person is balanced, the line of gravity must line through the base of support, in this example, the heads of the metatarsals and the toes. You can in fact analyze the movement about the axis between the ball of the foot and the floor, but you need to use the total of forces pushing down through the ankle. This includes the compressive force from body weight (minus the foot, which would need to be addressed separately) and the compressive force from the gastrocnemius and soleus. This will show there is not really a mechanical advantage. Through analysis at the ankle, you can see the that gastrocnemius and ankle are part of a first class lever system. This results in mechanical disadvantage through most of standing plantar flexion, but the gastrocnemius may reach a slight mechanical advantage at full plantar flexion.
This is not a personal critique of Dr. Goodin. I just started watch his videos and I am very impressed.