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Dr. Hamilton's Replies to Questions on the Youtube Channel

Last updated: June 6, 2023

Video Title: Dr. Marc Hamilton, Developer of SPUs (Soleus Push Ups), teaches how to do them

Video Description: This is the first introductory lesson for how to do the soleus push up (SPU) technique properly. It is part of a conference series in 2023 for physicians and their patients. However this is freely available, and everyone may use it to choose to improve metabolism anytime they are ordinarily sitting. Everyone is highly encouraged to frequently visit the associated website for much more information that will be updated weekly.

Reply to Steve's comment "Am still not clear on how many pushups to do in a single sitting...or for how many receive benefit.":

"Thanks for sharing your concern to work towards the goal of developing a solution for the massive amount of sluggish muscle metabolism throughout the day. As to how many minutes in a single sitting, the short answer is that you finally get to choose. One simple but certain fact is that the fuel burned during elevated muscle metabolism is much like the gas burned in your car; when it is working it is guaranteed to use fuel, but when it stops working the fuel demand quickly drops back to low levels. Ordinarily, people sit with inactive muscles for about 70 hours per week; giving you LOTS of opportunities to benefit as much as you choose! So instead of thinking that there is a minimal or maximal prescription, I hope well meaning people like you encourage others in need that you care for to choose how much to keep your muscle metabolism humming at a healthy rate. We are recording a series of on-line lessons as part of a seminar to answer questions like this in more detail. In the iScience publication (that you can access freely from the website), notice in Table 3 that as soon as blood glucose is starting to rise in the first half hour after ingesting carbohydrate it is already quickly improved by the SPU activity. So the effects are evident quickly for glucose, and even quicker for some things like blood flow and the burning of fat and glucose by oxidative metabolism."


Reply to John asking "Are you going to do studies on these with people who have Metabolic Syndrome?":

"Great question. Metabolic syndrome is caused by insulin resistance (a condition where the normal rise in plasma insulin is not able to help remove enough blood glucose in part because muscles have problems using blood glucose). Look at Table 4 in the iScience publication (that you can access freely from the website). Notice that in people who had impaired fasting glucose (a criterion of the metabolic syndrome), and in the people with obesity (a criterion of the of the metabolic syndrome) even the lowest intensity of SPU contractions we studied (SPU1) caused a large 40% reduction in the glucose excursion in the OGTT (oral glucose tolerance test). We also found that regardless of gender, age, habitual sitting time, or habitual walking steps per day, each subgroup improved significantly as a result of doing the SPU activity."


Reply to a user who asked "This is basically a seated calf raise that can be done on a seated calf raise machine at the gym? Does adding weight to the exercise enhance the effect?":

"I hope everyone can read your comment. And I will even extend your question to the related issue about the nomenclature. The short answer is no; this is not “basically a seated calf raise that can be done on a seated calf raise machine at the gym” and adding weights is not advisable. SPUs provide a metabolic solution for the larger part of time of the day when not doing your current exercise routine. The calf raise is a type of resistance training performed for seconds-minutes that does not rely on oxidative metabolism to fuel the muscle. Calf raises have another purpose than SPUs. When taught correctly, SPUs sustain a remarkably high oxidative muscle metabolism in the soleus for as long as you need to sit and choose to keep your metabolism at a healthy level. After much research in developing SPUs, this specific biomechanical movement without any more weight than the load of the legs (~25% body weight) was found to be effective at sustaining (for hours during normal sitting) a higher rate of local oxidative metabolism by the soleus than fatiguing treadmill exercise (or the fatiguing calf raise and low energy demanding fidgeting (AKA, leg bouncing or fluttering the leg). SPUs do not cause the soreness or fatigue like with resistance training or when using other muscles. Watch our recent 16 min video on fatigue to get to experience a fatigue test for yourself and learn more. We have a note about the nomenclature in the FAQ page of the website. In the iScience publication, we used the SPU terminology because the relatively high soleus electromyography (EMG) on-time (i.e. soleus activation) coincided specifically with upward angular motion of the ankle. This is different than what happens when doing other kinds of calf exercise. Because of this, when we teach it to research subjects, we do not tell them to visualize “raising the calf”, but instead to push forward and down on the ball of the foot and that in turn will cause the leg to rise up. You can also watch a 3 min video where I was interviewed in September of 2022 by the University of Houston communications department to help avoid potential misperceptions about the unique methods of the SPU movement."

Reply to a person who is now doing SPUs, "I actually enjoy this pushup. The first few times I experienced a rush of energy and I felt fantastic. My metabolism can use the boost. Thank you!"

 Dear “Search4Answers” (a thought provoking name), your kind of comment is insightful to learn more. Please do either share with me by email and/or here some details if you don’t mind. The “rush of energy” and feelings of soleus activity that some people feel is worthy of studying. We live in a time where lethargy is seemingly intractable. It’s hard to study feelings. But maybe with millions of different kinds of people now doing SPUs all over the world, we and other researchers can start to learn the connections between elevated muscle metabolism and feeling better.

Reply to a user who said, "Ive watched all the videos. When i practice doing it, it seems that no matter what i do i can feel other calf muscles contract too. The problem is i don't know where i should feel the soleus working, is there a way to feel it with your hand that it's contracting to create a mind body connection and isolate it?

The only way we have to instruct people outside of my laboratory is by our website newsletter ( Sign up if you haven't already.  When it is feasible, I have been asked to provide an on-line video seminar with instructional techniques for the thousands of physicians around the world that have been teaching their patients. Hopefully we can include something for people who are learning on their own. There are 3 tips suitable for here. 

1. The part of the brain controlling movement, motor neurons, and muscle cells are all very "plastic" (meaning they can be molded into becoming good at something, when you make them do something frequently). Whenever you sit, view that another opportunity to strengthen that brain-muscle connection. We definitely have the time. You likely sit 50 times a day, for 10 hours in total.  Muscles and the neurons that control them are really good at learning if you frequently practice something. The frequency that you use a muscle (times per day, cumulative times per week) and the duration (hours per day, cumulative hours per week) is directly related to how much learning takes place for something like SPUs. Like the Nike commercial use to say, "Just do it!"  
2. The soleus does have smaller helper muscles. The soleus is deeper than the lateral and medial gastrocnemius. See the graphical abstract on the front page of our iScience paper too see the anatomy.These other muscles will shorten and lengthen during the SPU movement. Even in muscle fibers that are completely passive, the SPU movement will shorten and stretch those muscles. 
3. Most likely you should not expect "feel the soleus working". It is sort of like you do not have a strong feeling that your heart is pumping, your diaphragm and other helper muscles in your chest are contracting for breathing. It depends on the muscle AND the type of contraction how much you can feel a muscle working. Related to this, there are sensory receptors in muscles to send signals back to the brain to say when the muscle is stressed, and the brain responds by raising blood pressure and heart rate.  But with SPU contractions, the soleus does not get fatigue and get stressed. That agrees with the finding from our publication that reported SPU contractions have little to no effect on raising blood pressure and heart rate like some other types of muscular activity.

Reply to Paramon, "Hi sir u think spu [with] assisted stimulation can help?"

I could say much more later, but the short answer is this. Think of either artificial electrical stimulation as possibly (at best, but not necessarily always) as a "supplement" to SPUs, because even the lightest level of SPUs that we studied is more potent (better soleus activity) than artificial stimulation (even to the point that stimulation causes uncomfortable pain). Part of the reason is that the motor neurons in the brain and spinal cord that stimulate the soleus have a wonderfully low threshold for the effort to activate the soleus when doing SPUs. Put simply, if I asked you to do light SPUs, the soleus is contracting more intensely than you can tolerate with a stimulator, and also more intensely than you can voluntarily do with other muscles for the same effort. Simply put, why choose something less effective, less practical, and that costs money when you can do something better for free anytime and anywhere you sit.

Reply to Alyssa, "Are the results different if the legs are alternated between SPUs? Either every other, or several on one, then several on the other leg. Do you have any data to show difference (if any) in benefit? Similarly is there data to suggest doing 2 legs at once is better than 1 leg?"

If everything else is identical, yes the optimal approach is to use both legs. But to either learn how to, or if sitting in a place it’s hard to use 2 legs, 1 is definitely going to raise muscle metabolism significantly more than just sitting inactive. Also, when using 2 legs, sometimes people will continually push one up while simultaneously lowering the other leg (like when walking). It’s a constant but opposite movement of the 2 legs.

Additional question from Alyssa, "How often do contractions need to be? Was the rate in the experiment 50/minute with a ROM at 30°? You say that ROM is more important than rate, but is it possible to do these too slowly? I find my natural inclination is 1 rep every 2-3s and am not sure if it's necessary to increase rate."

When learning on your own outside of a research experiment, the best advice is to get started with what is safe and comfortable for you. The motor skills will change over time. Listen to good music and have fun with it. It’s like learning to throw a ball or swing a golf club; at first you might consciously over-think it. Expert advice helps provide guidance, but that’s often best delivered one step at a time.  Eventually it automatic and so natural that the soleus can work remarkably intensely without any thought. Like I said in the video, a smooth fluid motion helps with raising the range of motion. It’s OK to learn with one leg. There is no ideal rate for everyone. Focus first on time per day. But like I said before, the optimal rate to raise soleus metabolism is definitely far less than that super fast leg fluttering some people do when fidgeting.

***I’ve provided some guidance already and will continue to try to find time and resources to direct doctors and their patients with the most trustworthy educational materials available. 
Warning: everyone should be careful when you see people who are not the research experts that spent years developing the SPU biomechanics.  My lab has forthcoming methods papers building on years of work. But unfortunately anyone can chat on a podcast or YouTube video without that research expertise, and needlessly confuse you about random leg shaking and fluttering. That’s irresponsible when by doctors people need to trust became educated before giving advice.

Video Title: Fatigue Resistance of the SPU (Soleus Push Up) demonstrated by the Developer, Dr. Marc Hamilton

Video Description: This provides people a memorable experience to quickly learn how fatigue resistant the soleus muscle is, when doing SPU contractile activity. This is a simple experiment to easily feel the contrast in how another nearby leg muscle is quickly fatigued. This is part of a seminar series provided for physicians and their patients, but also freely available to anyone else. If you want to learn about how your body works, in a truthful and clear way, then feel free to subscribe to this video series.


Dr. Hamilton's pinned comment: "60,000+. That’s the answer to the common question I am asked “How many combined  soleus contractions do your 2 legs always achieve in a day because of SPUs? But I also remind people it’s better to think about the “daily  contractile activity TIME” instead of  “steps/day”. 

By choosing to take advantage of SPUs, it guarantees the local energy demand in my soleus muscles during my normal sitting time stays very high. How high? Significantly greater than if I could take 100,000 walking or jogging steps/day. But there is zero competition between SPUs and any type of exercise I want to do, because SPUs don’t cause fatigue, and only reduce the time I would have to spend sitting inactive."

Reply to Linda, who thankfully commented "Dr. Hamilton!  So glad you are speaking directly on this subject.  Others try to interpret your work but you explain the concept best.  Looking very much forward to more.  Thank you!!":

"Thank you Linda. Feel free to let us know what points you want to learn more about. You are right that it is always best to go directly to the source. So feel free to ask questions and comment when we can help clear up something that others may have said that appears inaccurate or not supported by our research papers. We are glad to help clarify things with simple and accurate explanations in either the website and/or video lessons."

Reply to a thankful viewer who said "Doc you are saving so many lives incredible":

"We are doing our best. It is good to see people from remarkably diverse backgrounds around the world and from remarkably diverse cultures to live a more active healthy lifestyle. Admittedly, there is still much to teach the world about the best physiology and biochemistry so everyone knows better about how their bodies work. I encourage you and others to make it a goal to keep learning, and ask when I have not explained something enough."


Reply to Dilek asking "Hi. Should we leave our feet uncontrolled way when lowering after raising them? Or should we do it in a controlled way?":

"Yes it is a controlled smooth movement on the upstroke, and then relax so it is passive coming back down. See the short introductory instructional video that my lab recently put on YouTube to start. Expect to continually improve throughout the coming year in both your technique and lifestyle habits. Be careful listing to others that were not directly involved in the research. We explained in the article and prior videos that it is not uncontrolled fidgeting or leg shaking, etc. Somewhat like learning to ride a bicycle or throw a ball, with time it becomes an automatic habit that does not require much thought, but it is still a controlled movement. We will do our best to teach explain in much more detail both on a website and in videos."

Reply from a user who said, "Another great video. I feel no fatigue I feel warm from head to toe. This is absolutely amazing. The human body is a miraculous machine, thank you for tapping into one of its many wonders and sharing it. Thank you."

You are welcome. As this becomes a habit over a period of months, there are a series of waves for additional responses that are less common in the first week. In part because of the feasibility and safety, SPU muscular activity is designed to provide you the unique benefits of keeping your muscle metabolism elevated for more time per day than anything else. That leads to unique feelings and physical responses we are still learning much about.

Reply from Selvi, a Turkish user who said, "Vermis oldugunuz  aciklayici ve degerli bilgiler icin cok tesekkur ediyorum🙏⚘💚 gun icinde ne kadar süre bu kaslari çalistiracagiz .yeterli dediginiz belli  bir dakika yada saat varmi🙏🌹" Translation: Thank you very much for the explanatory and valuable information you have provided

You are welcome! As far as the time YOU GET TO CHOOSE to do SPUs habitually, think of it this way. The muscle metabolism is elevated IMMEDIATELY once you start doing it. So when you sit down, start doing SPUs if even for just 2 minutes. I bet that you will find it hard to stop at 2 minutes. The high soleus metabolism can be SUSTAINED at an elevated level for as many minutes AS YOU CHOOSE. How many people in the world do you think will one day say it is really odd to ask someone like me, "how LITTLE may I do something that is safe, free, and good for me?" For me personally, I want to spend as much time doing things that are good for me, so long as I don't have to stop doing something else that is good for me. But with SPUs, I do not have to give up anything else; I still exercise as much as possible. But I must spend at least 7-10 hours/day awake and sitting like everyone else. It is fascinating to witness millions of people in diverse cultures around the world who have begun to understand why and how to replace unhealthy sitting with a very healthy special kind of soleus metabolism. Here is what happens frequently. It is not uncommon for people to at first make a goal of finding just one place they know they will sit every day for 30-60 min, and decide they can and will comfortably do SPUs in much of that hour. Within just a week, they realize they can keep this up and eventually spend more time raising their metabolism with SPUs than any other exercise as they get older. They also start to realize just how many hours they needlessly were living with a low rate of muscle metabolism. They start to appreciate the undeniable scientific fact that no matter how much they exercise or manage their nutrition, muscles do not need much fuel (from either fat or glucose) to make energy when the muscle is resting with a low energy demand (like your car not needing much fuel when it is parked). Then finally, most people who over time learn how to do SPUs better and better each week, end up finding it an automatic habit that fills up 25%, 50%, or even more of the time they are sitting throughout the week.

Reply to an earlier commenter who said, "Merhabalar🙂vidyodaki konusmalarinizi anlayamadigim icin aoruyorum.dizimizle ayak ucu  ayni hizadami olacak bide her saniyede birmi yapacagiz.tesekkurler iyiki varsiniz🙏💙💚⚘" Translation: Hello, I'm sorry because I can't understand your speech on the video. Will our knees and toes be in line with our knees, we will do one every second. Thank you very much⚘

The SPU is most effective to improve your health AND fortunately also most comfortable when done correctly. One tip I was giving was to place the toes below the knee, rather than putting the toes in front of the knee. Sometimes this is easier to do when you slide your hips forward, and sometimes this is easier if you pull your feed backwards (depending on what you are sitting on). The reason for this optimal position is that it makes your soleus muscle strongly positioned for pushing up your legs to a higher level, while also elevating your metabolic demand much greater than in other positions. The research study shows you can increase your metabolic demand (energy for muscle work) more than twice as much by this little tip. If I missed giving you a complete answer, I am sorry because I may not understand your comment because I am still learning your language. Please ask a follow up question if you want more help.

Reply to a user who asked, "Is there any risk of overuse injury by doing SPU's. A lot of people have problems from doing repetitive tasks daily even if they don't feel demanding."

There have not been overuse injuries in research my lab has supervised. Your question is good and raises several issues we haven’t had time to comment enough about.  Even elderly people in their mid-90s or people who have never done any previous exercise have not had side effects. Part of this is hopefully that they get good expert supervision. Part is good technique (more videos to come). A big part is also fortunately the human anatomy itself! We documented some of this in the published article. SPUs move the ankle in the normal range of motion as in walking but without holes or uneven ground to cause twisting. The weight lifted during an SPU is only 25% of body weight. The soleus is naturally built stronger than other muscles, and the Achilles tendon is also remarkable. Ankles don’t get arthritis or need replacement as much with age like knees, hips, vertebrae, shoulders, wrists, etc. So yes, “it’s the right movement for the right muscle” for prolonged contractile activity. 

Important general point: anything done incorrectly can cause problems. So keep learning and I’ll try to offer explanations of what we learn through research. If pain occurs, then stop, get advice, and evaluate how to safely do it best. As with many things, people have to be their own life coach and become educated by only genuine experts. This YouTube channel and the website are largely in RESPONSE TO observing for the past 8 months millions of people trying it on their own. 

So what about the high dose of muscle metabolism we emphasize in our studies?  Is it “fanciful” to think there would be any practicality to it, as one respectable PhD once described this line of research? The recent public enthusiasm after the first SPU paper from my lab was unexpected.  We set out on this research path decades ago simply because we took a physiological perspective to learn how the body works. SPUs are obviously unique from other popular types of muscular activity. This surely isn’t about taking short-cuts or a quick fix. Benefiting from muscular activity over the whole day takes commitment. Gimmicks aren’t focused on physiological methods as much as they are lowering the bar to the point of ineffectiveness. We all know the popularity of watches giving people a reminder to stand up at the end of each hour, even though it’s proven impotent. There have always been a lot of public health messages focused on “how little time each week can we advise people to be active”.  That kind of attitude is not driven by human physiology as much as it is marketing.

Reply to a question from Asad Mahmood, "Hello Doctor. May i ask do we have to do both legs at same time or can we just do one leg in session? Is it as effective as lets say doing soleus pushup of both legs together? Waiting for your kind reply. Thanks in advance and keep up the good work you are doing to humanity. I salute you, sir."

Thank you for your polite question. Sometimes 1 leg alone is all you can do depending on where you are sitting. In that case, know that 1 leg doing SPUs well can be impressive. In theory, if you were doing a highly controlled experiment and measuring fuel used for working muscle, then 2 legs would use 2X more fuel than 1 leg. But I’ve seen that when sitting where the floor or chair/sofa are not like I like it, the 1-leg kind is better. The rule of thumb is to keep moving because no one can have a very high muscle metabolism when muscle isn’t active.  But like I said in the video, you can be guaranteed that when soleus is working for you, it must use a lot of fuel. Compared to the energetics of all 600 of your resting muscles combined (one-third body weight), most people can learn how to keep muscle metabolism at a level 4X higher each minute they choose to do so with 2 leg SPUs, or to double the body’s muscle metabolic rate by high quality 1-leg SPUs.

Reply to Alyssa, who asked "Hi Dr. Hamilton, I have several questions so I'll post them all separately to be easier to respond to. In reading all the other comments I understand you like to frame the question as "how much can we do" as opposed to "what is the minimum effective dose". Are we to assume since glucose lower benefits kicked in at the 30 minute mark that ANY amount is better than 0 amount and it is worth accumulating time in 10-15 minute increments if that is all we are able or willing to do?

I’m not sure of your question but suspect it’s a general statement about “what’s a good tip for a starting point” as to how long to do SPUs. For everyone just getting started, it’s ok to start with as little OR as much as is right for you personally. My lab team has a lot of experience and expertise from working with all kinds of people. One general rule of thumb is most people end up surprising themselves. I sometimes tell people, just make the small goal of 2 minutes of SPUs each time you sit down. That’s easy of course. But once they go 2 minutes, they do more. People often realize “since I have to sit throughout the day anyway as part of normal life, I might as well also include SPUs as a habit and raise my metabolism for more time than I am already doing with my other exercise habits”.  So for example if you sit down for 15 minutes to talk on the phone, make the goal of learning the habit to start doing SPUs for the first 2 min. That may turn into the whole 15 min phone call. Then later in the day you may sit to watch the TV news, now you may get another 15 min. Before you know it, you will be doing SPUs more time than you’ve done any other muscular activity.

Reply to a forward-thinking question from Alyssa,"Can you tell us what research questions you are currently investigating that have spawned from this article's findings?"

Lots. The article you’ve seen was just the tip of a much bigger iceberg. It will take forward thinking people of all types, to provide funding, and to assist in other ways.  There are many various metabolic health issues that must be addressed.  But research can address how a high dose of low stress soleus activity impacts brain health, cardiovascular health for multiple disease conditions, aging well, movement disorders of several kinds, fatigue disorders and inflammatory issues often related to autoimmune problems. 

SPUs have opened up the door to researching many questions related to the general issue of “what happens in our human bodies” now that we have a way for very intense soleus muscular activity to be sustained for many HOURS per DAY (not just 75-150 minutes/week like most public health goals have been for traditional exercises). Think about that. 

We reported in the first article only on some of the glucose and lipid metabolism effects in a single day of doing SPUs. But there are long term adaptive benefits to muscular activity that aren’t evident in just one day.

Reply to a viewer who asked, "When can [we] do this exercise to lower [our] blood sugar level?"

The best approach is to habitually use this to keep muscle metabolism elevated throughout the times of day whenever sitting. That will improve not only glucose but other important things such as doubling fat oxidation. But the more limited acute option you you may have inferred was to do this instead of sitting when either blood glucose or insulin are too high  after carbohydrate ingestion (typically 30-150 min in the postprandial period).

Video Title: Soleus Push Ups (SPUs) cause a rapid and sustained improvement in glucose metabolism (Part I)

Video Description: This video lesson is in response to a common request by doctors and their patients after enthusiastically starting to do SPU muscle contractions. They ask good questions about glucose regulation that they want answered within a brief video discussion.  Make sure to watch and re-watch the final 2 minutes for the key message  to remember each time you sit down (regardless how much you already exercise).

Reply to Raven, "Thank you Dr. Hamilton! I have seen many posts from doctors demonstrating this movement incorrcetly, and of course posts on FB. I think a video series for the "layman" would be helpful."

You are right. Misinformation is a problem in general. Here are some interesting observations and practical ways everyone can help other people. 
- It’s not that there is any controversy about SPUs. Everyone knows people will benefit from a transition from sitting inactive 70 hours/week to instead using a lot more of that time to benefit from muscular activity! 
- Misinformation spreads rapidly, but so can truthfulness. When polite about it, people should sometimes speak up. 
-My sense is that many of the doctors who are teaching about SPUs and metabolism generally mean well. But none bother to “fact check”. That’s the process journalists from the past used to do in previewing their work with the experts who did the original study. Mistakes left unchecked spread. People tend to think doctors would be more careful to become educated before giving commentary to their patients or the public. 
- Creating an international network through the website newsletter is key. So anyone who wants to continue learning about muscle and metabolism in general should take part in that free service from the website. Videos like you requested will be included.

Reply to a user who asked, "Hi Doc, I was reviewing your paper this morning and sorry for the stupid question but what's the difference between SPU1 and SPU2? I tried a search on it and I can't find it stated on the document what differences are between the two?"

2 different levels of soleus energy demand and carbohydrate oxidation (glucose burning).  **Glad you asked because Fig 4B is perhaps the most important figure for everyone to print on paper, and study so frequently, that it is imprinted in your brain forever. (I won’t editorialize about Fig4B more here. Just think deeply about it.)

SPU1 = when the soleus caused a 50% greater whole body energy expenditure than sitting inactive. SPU2 = 100% increase total energy expenditure.  

Remember this: In Experiment 2, subjects were tested 3 times while drinking the exact same glucose tolerance test.  This allowed us to test glucose regulation at 3 metabolic rates (in random order on different days): once sitting inactive after drinking the glucose (sedentary control test day), once while doing SPUs at the lowest metabolic rise of soleus metabolism we studied (SPU1, 50% greater whole body energy expenditure than sitting inactive) and once with double the metabolic rate (SPU2, 100% greater energy expenditure than sitting inactive).  

The tables and figures (and the text of the paper) give additional explanations about SPU1 vs SPU2. A

You may want to listen again at about 9-10 minutes of this video, when the difference between SPU1 and SPU2 was also explained.

Reply to a user who asked a follow-up question, "Hello Dr Hamilton, Thank you for this additional information!  I’d like to make sure I understand the SPU1/SPU2 difference.  Did you create the 1.3 METs/1.7 METs difference by simply raising the angle of motion from 15% to 30%?  You make it clear that doubling the frequency of the SPUs didn’t have the same effect, I think?  The opportunity to hear all this explained by you is really wonderful; there are many people out there clearly excited by the promise of what you’ve discovered, who are trying to explain through youtube segments their understanding of the muscle and the method (some describing the “jiggling” and “fidgeting”) but I don’t find they mostly do justice to the concept.  I was introduced to your work by Dr Javier Gonzalez, Prof. of Nutrition and Metabolism, Univ. of Bath in England, speaking about it on a Zoe Project podcast, on youtube.  He’s a serious researcher but although he sounded intrigued and enthusiastic, his information was a bit incomplete.  Thank you again for your work!  These videos of yours need to be seen by a lot more people!"

We will provide MUCH more instruction in the continuing series of videos.  I will post more specific replies about the SPU1 and SPU2 in the study later.  First make sure and see (and re-watch occasionally) this channel’s introductory videos   already available.  You are correct that there have been many millions of people commenting about why and how to do SPUs. But second hand information is NOT a good clear way to spread trustworthy knowledge!  I can not control what others say. So it’s best for you and others to keep returning to this recent video channel and the website. My lab members and I will do our best to provide the most trustworthy education. 

For example, you asked for technical help how to obtain a good metabolic response by the soleus muscle with the SPU movement. In the instructional video notice I explained that “leg shaking/fidget ring” etc is NOT what we teach research subjects! SPUs are significantly more effective.

User response, "Yes!  Your explanations are very clear and you make your important discovery about the special qualities of the soleus muscle quite understandable.  I wish you the quickest way forward in getting this information to as many medical practitioners and their patients, as soon as possible.  Otherwise, the folks other than you, who try to explain by calling for “fidgeting”, will continue to unwittingly misinform.  I’ve added my address to the mailing list on the website and I’ll continue to watch for new videos.  Thank you so much!"

Reply to a commenter who asked, "Is this as efficient as blood glucose lowering drugs like metformin? Since these drugs have side effects, a safe alternative would be great"

The answer is yes, but even more important is HOW (the mechanistic process) it is different than drugs or nutritional weight loss methods. I was recorded recently answering similar questions so I’ll paste that below. Not sure what day it will be posted so I will paste a couple parts of the transcript.  

But also for everyone interested in these kinds of Q&A, if you subscribe to the YouTube channel and sign up for the free newsletter in the website, we can provide more than here. I’m not sure when those will be posted in the next couple weeks.  

Here is part of that answer, which is easy to remember if you have it in writing to review over the coming weeks. Plus knowing this will help motivate people to keep doing SPUs often when sitting. 

1. When sitting at rest to do SPUs, the Soleus (1% body wt) can steadily (for hours that you sit, not minutes like most exercise) burn more (2.9X more) carbohydrate by oxidative metabolism than all other muscles combined, plus also all other body tissues combined. In fact, my laboratory published results showing SPUs could raise and SUSTAIN oxidative metabolism of glucose steadily high for 180 minutes after ingesting 75 g glucose. How high? High enough to steadily burn 71 g of the total carbohydrate over the 180 min testing time. 
2. Drugs (and weight loss) work by different mechanisms than how SPUs work. Most help the body store the calories of glucose in the body as something called glycogen or fat.  That’s important to remember. 
Obviously drugs aren’t made by the body naturally and thus will have side effects like you mentioned. But also because glucose lowering drugs do not work by raising muscle metabolism, it means some drugs can add to the glucose lowering of SPUs.        

I’m also often asked if pharmaceuticals may one day replace physical activity. My answer is not likely, at least not with near the same potency for raising oxidative metabolism of glucose and fat as much as SPUs.  The follow up question is always about the public health recommendations for physical activity.  My work differs from the opposite trend by others that emphasize “how low can you go” (how little time per day can have some effect).  My lab work has been unique in having mostly focused on prolonged contractile activity since the 1990s. This is different than the way most researchers prefer to focus on questions like “how little activity time can we recommend”.  Or “can we find a way with drugs, without raising muscle metabolism”. 

I’d prefer to offer something different for people who are hungry to stimulate health by raising muscle metabolism optimally by asking  “how much time can anyone safely raise muscle metabolism, to optimize health as much as possible”. Doctors and experts should just be honest with people and explain staying active (for hours, not minutes) is best for raising and sustaining oxidative metabolism. Our first article about SPUs explained twice, with references from published studies by other labs to also look up, that exercise only raises glucose oxidation in the minutes the muscles are active.    In summary, remember this! If the body isn’t given something like SPUs to burn glucose (and fat) as a fuel for oxidative metabolism, then that sugar and fat is stored inside the body.

Reply to Weekend Warrior, "How is it different from doing a standing or sitting free weight calf raise done in any good strength program?"

Glad you asked it so clearly because I’ve seen things like this asked to other scientists and doctors who haven’t studied it like my lab does. I’m assuming someone with the “weekend warrior” nickname loves to lift weights. Great, it’s one of my favorite things to do every day too. I bet when you lift, including doing a seated or calf raise or standing one leg heel lifts you do go to failure with as high of load as it takes to fatigue quickly. Maybe 10 reps, maybe 30 reps per set? If you go hog wild you might do a total of 200 reps. And you might give your soleus and other leg muscles 2-3 days per week of that heavy training, knowing that any more and you won’t adapt and over time risk serious injury. Now consider this. I do at minimum 60,000+ daily (7 days/week) soleus contractions. No need to take a day off. Which is a good thing because I want optimal metabolism every day. I also don’t take a day off from drinking water! In fact I try to drink water more than one time a day, because I know the human body thrives on staying well hydrated all day, every day. The cardiac muscle and diaphragm are 2 muscles that also don’t take a day off. Soleus muscle metabolism is sort of the same way! The human body thrives on some kinds of muscular activity, done frequently. SPUs are the only kind of muscular activity that I’ve seen to be developed specifically to raise soleus metabolism to very high levels, for inducing benefits of very prolonged contractile activity, specifically to optimize the health and metabolism of the rest of your body.

Also see the first video we published about fatigue resistance. We explain why the unfit research subjects tested over the critical 180 min postprandial period after ingesting carbohydrate were able to comfortably maintain SPU activity each of those 180 minutes. We also tested other even more unfit volunteers in a 270 min test. In the video we demonstrate how you can try a simple experiment to see how the soleus feels much less fatigue than another neighboring muscle used while sitting.

Reply to Alyssa's Question, "How long does the glucose lowering benefit last once the exercise is stopped and is it dose dependent? For example, if I did 4hrs of SPUs would the prolonged benefit be greater than if I did it for only 1hr? It would be interesting to see graphs like figure S10 that continue for a few hours after SPUs have stopped to see the glucose/insulin response."

"Additionally, table 3 shows the numbers and statistical significance for glucose concentration but there is there an equivalent table for the insulin information (other than just S10). Is insulin statistical significance beginning at 1hr?"

Yes insulin concentration is significantly less in the first hour.

First let me encourage you and all readers to read the Introduction and Discussion again. Your questions raise broader general concepts that are discussed in more detail in that text. Everyone is welcome to also comment on the text of the published article. 
Yes this SPU study clearly showed a statistically significant dose response. The same people were tested 3 days each with the identical 75 g glucose challenge over 3 hours.  The 3 tests compared different level of muscle energy demand (2 levels of SPU intensity, and in a sedentary control trial).  SPU2 was at twice the soleus metabolic rate as SPU1, and on average it reduced glucose and insulin more than SPU1. 

As for your other question about the timing, there are several things to consider. One is the time course of hyperglycemia after ingesting the glucose. SPUs performed during the glucose tolerance test reduced glucose throughout the entire 3 hour period. We tested that duration because that is how long these kind of people are hyperglycemic (high blood glucose) after ingesting glucose.  The Discussion of the article explained in more detail than I can here some of the reasons for the failures of more heavy “whole body” types of treadmill or cycling exercise to improve glucose tolerance. Acute exercise performed before ingesting the glucose generally does not improve glucose tolerance, and sometimes makes it worse than just being sedentary. 
Finally, in other studies we and others have done, it is clear that the more time you work muscle, the more you will benefit all of the processes improved by oxidative metabolism (glucose, insulin, blood lipids, blood flow, etc.). 
**It doesn’t matter what kind of exercise you do, muscle has a low rate of oxidative metabolism when it is not working! (That’s why my lab has had the goal of developing a way anybody can keep muscle metabolism high for hours, not minutes each day). THAT POINT IS A GOOD TAKE HOME MESSAGE!

Reply to the question, "Perhaps showing my ignorance, but in figure 4A and B, why does one graph say carb oxidation and the other glucose oxidation? Are they the same thing? Are those two graphs basically showing similar results (that SPUs burn more energy) but over different units/time scales (mg/min vs total g)?"

The data from the 2 graphs in Figure 4 are the most fascinating results to some people. I’ll explain it more in an upcoming article where we go into more depth. But here are some easy helpful tips to use when studying 4A and 4B. 4A is showing individual results. See how there is a wide variation between individual people at the start when fasted overnight. Then when ingesting the 75 gram glucose load, when sitting INACTIVE some people are unable to raise carbohydrate oxidation much, and no one raised it nearly as much as could be done when sitting the same 3 hours but doing SPUs. In fact, everyone could quickly and profoundly raise carbohydrate oxidation with SPUs. This means the soleus metabolism is “flexible” (burn fat when it’s the right time while fasted, then switch to burning carbs after ingesting carbs). Cool huh!  
Notice in 4a also that SPU2 was a higher SPU metabolic rate than SPU1, and you see there was an expected dose-response. SPU2 burned more of the sugar than did SPU1 because it needed more fuel to do more work. 
Fig 4B was calculated from the data in 4A and shows a mathematical model of what is happening. Knowing that SPUs didn’t use glycogen, the carb oxidation was assumed to be almost entirely from blood glucose. Now remember that the video (and article) explained a hugely important background fact everyone should know (but often don’t); there is not very much glucose in the blood, even during diabetic hyperglycemia, if you compare that blood glucose to the amount that can be burned to fuel the Soleus metabolism during SPUs!  
In summary, SPUs are a potent physiological method to burn up (ie oxidative metabolism) whatever the rise in glucose happens to be during hyperglycemia after ingesting a moderately large glucose load. 
Simplified, this means the soleus may only be 1% of the whole body weight, but it can easily burn down blood sugar to reduce hyperglycemia. It can do this DESPITE at the same time reducing the body’s dependency on insulin by more than half normal. Lower insulin is healthier for many reasons, but only when the muscle can extract lots of glucose despite lower insulin concentration.

Reply to the question, "You responded to a question about applicability to those with MetSyn in your "how-to" video comments, referencing table 4. I'm curious about a friend of mine who has MetSyn [Metabolic Syndrome], but also has problematically LOW blood glucose levels. Do you this exercise is advisable for people like this, or is more information needed?"

Metabolic syndrome is in large part related to insulin resistance. That’s why one of the criteria for it is higher glucose and triglycerides. Subjects that improved those variables included some people with Metabolic Syndrome. You mentioned the friend had lower than normal blood glucose, which obviously is the opposite of the more common diagnostic criteria for that condition. Regardless, notice the other 2 recent questions where I answered that SPUs switch to using fat oxidation when glucose is not at high levels. That helps to explain the lowering in triglyceride we reported on. In fact, the isolated soleus under the low stress conditions of doing prolonged contractile activity (SPUs) is the perfect biochemical situation for fueling muscle by fat instead of glucose.

One other related thing to notice. SPUs reduce insulin by a large amount. This lower than normal insulin helps to reduce blood glucose uptake by various body tissues. This also helps to promote less fat storage and more fat use. These actions together help to avoid hypoglycemia when doing SPUs.

Answer to a question with a critical misunderstanding, "Can you achieve the same goals with standing SPUs compared to sitting SPUs?"

No. First of all, most people sit inactive with a low metabolic rate for 70 hours a week. That’s a great time to use productively to raise muscle metabolism by also doing SPUs. Secondly, even if you did stand a bunch more than most people, the weight on your feet (and this load lifted by the Soleus) is 4X greater when standing than when sitting. That high load does at least 3 things that DEcreases the optimization of Soleus energetics. 1) a high load decreases the shortening velocity and range of motion, which we showed was a key to how high the soleus energy demand is for SPUs, 2) there is much eccentric stress on the Soleus in the standing variety to lower body weight that doesn’t happen in the seated kind (eccentric contractions don’t use much energy but damage muscle), 3) even athletes fatigue within minutes of the standing kind but our research showed that even unfit people can sustain >4-5 hours of a high local energy demand above walking or running by doing SPUs when done correctly.

Reply to an insightful question from Alyssa, "If soleus pushups are performed in a fasted state and blood glucose is already low (let's say 80 or so), what will be the response of continuous SPUs? Will they still use glucose from the blood as a fuel source (causing the pancreas to release glucagon) or start burning through more glycogen?"

Great question. Notice in the published research article that the soleus uses fat to fuel SPUs, not muscle glycogen, when not challenged with high blood glucose. There was negligible soleus glycogen use (2% of the activity energy expenditure to be exact!) in between the two biopsies when people were relatively fasted between meals. ***everyone can remember this easily as follows: “the soleus is opportunistic when doing SPUs!” 1) it will burn blood glucose when the blood glucose delivery is high; 2) it will use fat when it’s best to burn fat.   BTW- here is a careful caveat; this is true about the soleus when doing SPUs. In contrast, we also know the soleus will burn lots of muscle glycogen when walking because it’s a large muscle mass exercise and metabolic control isn’t the same as when targeting only the soleus by SPUs (1% of body weight).

Series of comments from a user who posed the question,

"I wonder if there are other muscles like the soleus? I've wondered about the muscles used to raise the shoulders. As with shrugging. As the shoulders spend a great deal of time in a semi-raised position when one is tense, but don't seem to fatigue, either. But I can't think of a corresponding natural activation of the soleus muscle although, I was one of those kids who unconsciously bounced my legs when I was forced to sit still but it wasn't in the form of bouncing my heel off the floor. It was all "up in the air", with the heel off the floor. Up around the highest point of a soleus pushup...and very fast. It was so strong that it would create a sort of frequency with which other things would resonate. And I could do it all day long."

No. The molecular machinery and the anatomy of the soleus is known from decades of research to be unique from other muscles. Secondly, the specific type of muscle contraction developed for the SPU uses MUCH more energy and thus fuels like glucose and VLDL triglyceride (fat transported in the blood that causes heart disease). Some muscles can’t use blood glucose or VLDL well even when they are working. And the soleus doesn’t use much energy and these fuels when at rest. The soleus is special because it is the main muscle in the body for balance when standing and walking. Our study reported that the SPU done properly as we developed it likely uses 5x more energy than brisk walking and 2X more than running to exhaustion in a minute or two. The examples you give of shrugging the shoulders and fluttering are also not as effective, because they are use significantly less fuel.

"Interesting - I wonder if the soleus could be the "newest" muscle, evolutionarily-speaking, as for walking's all fascinating. Thank you for posting these corrections and clarifications regarding your study."

The soleus is uniquely well suited for fatigue resistant activity in all animals it has been studied. But there is a major anatomical difference in that humans have a soleus mass 10X bigger than in most animals (after normalizing to either body weight or total body muscle mass). One likely reason for this is it is more important for humans to stand and walk on just 2 legs while other  mammals walk differently.

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