A simple, groundbreaking exercise developed by researchers at the University at Houston can help boost metabolism in the sedentary office-based lifestyle that causes so many health problems. By using the soleus muscle in the calf, though accounting for only 1% of the body’s weight, the metabolic health of the rest of the body can be boosted – if this muscle activated in a very specific way.
Marc Hamilton, professor of Health and Human Performance at the University of Houston, has discovered such an approach for optimal activation: the “soleus pushup” (SPU) which effectively elevates muscle metabolism for hours, even while sitting. The soleus, one of the human body’s 600 muscles, is a posterior leg muscle that runs from just below the knee to the heel.
Prof Hamilton’s research, published in the journal iScience, suggests the soleus pushup’s ability to sustain an elevated oxidative metabolism to improve the regulation of blood glucose is more effective than any popular methods currently touted as a solution including exercise, weight loss and intermittent fasting. Oxidative metabolism burns metabolites like blood glucose or fats, but it partly depends on the immediate energy needs of the muscle when it’s working.
“We never dreamed that this muscle has this type of capacity. It’s been inside our bodies all along, but no one ever investigated how to use it to optimise our health, until now,” said Prof Hamilton. “When activated correctly, the soleus muscle can raise local oxidative metabolism to high levels for hours, not just minutes, and does so by using a different fuel mixture.”
Muscle biopsies had revealed that the soleus used minimal glycogen – the predominant carbohydrate for fuelling muscular exercise. Instead of breaking down glycogen, the soleus can use blood glucose and fats.
“The soleus’s lower-than-normal reliance on glycogen helps it work for hours effortlessly without fatiguing during this type of muscle activity, because there is a definite limit to muscular endurance caused by glycogen depletion,” he added. “As far as we know, this is the first concerted effort to develop a specialised type of contractile activity centred around optimising human metabolic processes.”
When the SPU was tested, the whole-body effects on blood chemistry included a 52% improvement in the excursion of blood glucose and 60% less insulin requirement over three hours after ingesting a glucose drink.
This new approach of keeping the soleus muscle metabolism going also doubles the normal rate of fat metabolism in the fasting period, reducing levels of VLDL triglyceride.
The soleus pushup
Building on years of research, Hamilton and his colleagues developed the soleus pushup, which activates the soleus muscle in a different way than standing or walking does. The SPU targets the soleus to increase oxygen consumption more than what’s possible with these other types of soleus activities, while also being resistant to fatigue.
While seated with feet flat on the floor and muscles relaxed, a soleus pushup is performed by the heel rising while the front of the foot stays put. When the heel gets to the top of its range of motion, the foot is passively released to come back down. The aim is to simultaneously shorten the calf muscle while the soleus is naturally activated by its motor neurons.
While the SPU movement might look like walking (though performed while seated) it is the exact opposite, the researchers say. The body is designed to minimise the amount of energy used in walking, because of how the soleus moves. Prof Hamilton’s method reverses that and makes the soleus use as much energy as possible for a long duration.
However, the method is very specific, and if you are trying this while seated at your desk right now, you may not be doing it in the right way.
“The soleus pushup looks simple from the outside, but sometimes what we see with our naked eye isn’t the whole story. It’s a very specific movement that right now requires wearable technology and experience to optimise the health benefits,” said Prof Hamilton.
Additional publications are in the works focused on how to instruct people to properly learn this singular movement, but without the sophisticated laboratory equipment used in this latest study.
The researchers are quick to point out that this is not some new fitness tip or diet of the month. It’s a potent physiological movement that capitalises on the unique features of the soleus.
Potential first step toward a health care breakthrough
Prof Hamilton said it is the “most important study” ever completed at his lab, and could be a solution to a variety of health problems caused by spending hours each day living with insufficient muscle metabolism caused by inactivity. The average American sits about 10 hours a day.
Inactivity is a major health risk, and a low low metabolic rate while seated is especially troublesome for people who are at high risk for age-associated metabolic diseases such as metabolic syndrome and type 2 diabetes.
Prof Hamilton said inactive muscles require less energy than most people seem to understand, saying it’s “one of the most fundamental, yet overlooked issues” guiding the way toward discovering metabolic solutions to assist in preventing some age associated chronic diseases.
“All of the 600 muscles combined normally contribute only about 15% of the whole-body oxidative metabolism in the three hours after ingesting carbohydrate. Despite the fact that the soleus is only 1% the body weight, it is capable of raising its metabolic rate during SPU contractions to easily double, even sometimes triple, the whole-body carbohydrate oxidation.
“We are unaware of any existing or promising pharmaceuticals that come close to raising and sustaining whole-body oxidative metabolism at this magnitude.”
Source: University of Houston
