The soleus muscle has been drumming up quite a bit of attention in recent years for what researchers suggest is its unexpected and positive impact on health. A small but mighty muscle located in the lower leg near the calf, the soleus muscle contains slow twitch (Type 1) fibers adapted for long-duration endurance activities. Neighboring muscle groups tend to be dominated by Type II fibers more metabolically suited to short bursts of activity. Type 1 fibers in the soleus possess high oxidative metabolism capacity and are rich in mitochondria and myoglobin. It also contains a rare find for any muscle: a complex myo-connective structure that includes three intramuscular tendons and a robust capacity for resilience in the face of repetitive stress. Its Type 1 fibers utilize oxygen more efficiently, resulting in lower lactate production compared with nearby Type II-rich muscle groups.1
Engaging the soleus muscle more frequently may unlock hidden metabolic benefits, researchers say. Performing the soleus “pushup” (SPU) exercise is on par with a traditional calf raise movement, executed seated with knees stacked over the heels and feet rotated roughly 45 degrees to the outside. With sedentary work and lifestyles dominating the daily landscape for many, the SPU has been promoted by some as a simple, accessible, and effective way for people to improve their health, including modulating glucose and lipid metabolism.1,2 But does it work?
Research Insights
In an experimental physiological study published in Cell Press in 2022, authors evaluated 25 human volunteers in two sequential experiments, each using a randomized cross-over design so that individual participants could serve as their own internal control. Study participants consisted of a roughly equal distribution of sexes, with a moderately wide range in age, BMI, sedentary time, and free-living activity level.2
Experiment I tested the SPU contractions corresponding to ~2 METs (metabolic equivalents; helping determine the rate at which calories are burned). Experiment II tested SPU contractions at ~1.3 and ~1.7 METs. Both experiments involved testing a subtle elevation in whole body metabolic rate above resting by contractile activity while sitting, and EMG feedback with direct measurements of oxygen consumption helped guide the activity. In addition to soleus biopsies on each day, a blood sample was also obtained prior to the final biopsy for testing the effect of this small muscle mass activity on VLDL-triglyceride (VLDL-TG) concentration. The purpose of this first experiment was to study substrate metabolism over a prolonged bout of SPU contractions instead of inactive sitting. Standardized meals were provided for all three meals the day prior to testing in addition to the small breakfast on the test day. The study was timed so that a blood sample for measuring VLDL-TG and then the final biopsy were obtained about seven to eight hours after a small, controlled breakfast (7 kcal/kg, 33% carbohydrate, 14% protein, and 53% fat), which was provided 12 to 14 hours after an overnight fast.2
Impact on Glucose Metabolism
Researchers from this 2022 paper looked at the ability of the two levels of SPU activity to impact postprandial glucose and insulin, using a 13-point OGTT and collecting blood measurements from an indwelling catheter every 30 minutes throughout the entire three-hour postprandial period.
Within just 30 minutes, the SPU activity was already attenuating glucose concentration and buffering the rise. Glucose improvements continued and revealed levels significantly lower than the sedentary control measurements for up to 45 minutes. However, this effect was short-lived and present only between 30 and 45 minutes of the postprandial period, followed by greater hyperglycemia than the inactive sitting trial after exercise stopped. The authors explain that mechanisms of glucose regulation in the face of physical activity are complex, saying that they’ve focused on a method of raising slow oxidative muscle metabolism to complement—not replace—existing nutritional and pharmacological approaches for managing blood sugar concerns. Nonetheless, their conclusion from the study was that SPUs had the ability to improve systemic VLDL-TG and glucose homeostasis by a large magnitude with 52% less glucose excursion between the one- and two-hour postprandial period as well as 60% less hyperinsulinemia.2
Impact on Coronary Artery Disease
In the first of its kind to investigate the effects of SPU exercises on patients with coronary artery disease (CAD), authors of a new study published in 2025 in Medicine indicate that SPUs may have beneficial effects on the blood lipid profile, endothelial dysfunction, and associated systemic immune-inflammatory response in patients with CAD.1
A total of 43 CAD patients were enrolled and divided into two groups: 24 patients in the exercise group performed SPUs, while 19 served as the control group with no exercise recommendations. Blood lipid profiles and systemic immune-inflammatory index were measured at baseline, one month, and three months. At the one-month follow-up, the exercise group showed significantly lower total cholesterol levels and systemic immune-inflammatory index scores compared with the control group. At the three-month follow-up, the exercise group had significantly higher HDL cholesterol (HDL-C) levels and lower LDL cholesterol (LDL-C) and total cholesterol levels than the control group. The exercise group also had significantly lower systemic inflammatory index scores at three months. Researchers concluded that SPU exercises may positively influence blood lipid profiles and systemic immune-inflammatory index in CAD patients, highlighting a potential noninvasive approach for managing cardiovascular risk factors.1
The participants in this study performed the SPU exercise at least three times daily for a minimum of eight minutes each session, approximately one hour after meals, when postprandial glycemia and lipemia levels are expected to rise. Adherence to the exercise regimen was regularly monitored, and corrective feedback was provided when necessary.1
In addition to participant demographic characteristics such as age and gender, anthropometric measurements, including height, weight, and BMI, were recorded. The presence of chronic diseases such as diabetes, hypertension, heart failure, COPD, and cerebrovascular accident, along with any use of antilipidemic medications, were also considered. Among 24 patients who performed the SPU exercise, 20 were male and four were female, with a mean age of 60.67 (range: 39 to 80) years. The control group included 19 patients, 16 male and three female, with a mean age of 65.89 (range: 48 to 80) years. Authors of this study also point out that in pathologies like heart failure and COPD, the oxidative capacity and perfusion of the soleus muscle are impaired, leading to significant reductions in strength and endurance. This functional decline may limit exercise tolerance and overall physical performance. Therefore, preserving the endurance capacity of the soleus muscle could play a crucial role in enhancing the efficacy of exercise interventions for cardiovascular conditions, such as CAD.1
Takeaways for RDs
Dietitians are often caring for patients with diabetes and heart disease or those who are at risk for these conditions. They’re involved in guiding patients in dietary and lifestyle changes that may help improve outcomes and quality of life from multiple synergistic angles, including offering assistance in structuring daily meals and sharing insight on what physical activities may be appropriate. While not a substitute for nutrition intervention nor a replacement for other forms of beneficial movement, SPU exercises may provide additional support for positive change while being accessible to even those with the most sedentary lifestyles.
— Heather Davis, MS, RDN, LDN, editor
References
1. Gökaslan S, Yilmaz ÖF, Korucu C, Günlük NB, Balci A. Effects of soleus push-up exercise on systemic immune-inflammatory index and blood lipid profile in coronary artery disease. Medicine (Baltimore). 2025;104(31):e43643.
2. Hamilton MT, Hamilton DG, Zderic TW. A potent physiological method to magnify and sustain soleus oxidative metabolism improves glucose and lipid regulation. iScience. 2022;25(9):104869.