Most people are aware that resistance training provides an increase in muscle tissue and strength. This type of training also provides other benefits including weight loss, improved mobility and balance, increased bone density, and decreased risk of disease and injury. While much of this is common knowledge, how do we know that much of this is true? The study discussed below sought to prove that one short bout of resistance exercise is beneficial to lipolysis within fat tissue. Can just 40 – 45 minutes of moderate intensity resistance training burn fat?
Eight young males who were physically active and free of disease participated in this study. Participants attended the lab on three separate occasions, one to gain baseline information, one to act as the control day or, the day on which exercise was not performed, and another to perform an acute bout of exercise. The pre-qualifications and time spent in the lab were identical on both the exercise and control days, however, on the day on which exercise was not performed, the subject remained sedentary. Exercises performed included three sets of ten of each: chest press, lateral pull down, leg press, shoulder press, leg extension, and leg curl.
The methods explained
So the first visit was dedicated to baseline measures including collection of height, weight, and body composition. On the other two visits, participants were inserted with a microdialysis probe. This probe was used to collect measurements on blood flow and lipolysis, or the rate of fat oxidation. Other measures taken included energy expenditure and respiratory exchange ratio, both measured before and after exercise. Energy expenditure is the amount of calories burned per hour and the respiratory exchange ratio is a ratio based on oxygen intake and carbon dioxide output and determines if fat or carbohydrates are being used as fuel. Measurements were collected prior to and 45 minutes after the trial.
Following resistance training, the rate of fat oxidation was significantly increased. Energy expenditure was also significantly higher, possibly indicating that the enlarged rate of fat oxidation provided fuel for the increase in energy expenditure. The respiratory exchange ratio was significantly lower following exercise. This indicates that fat was the primary source of fuel, also confirming an increase in fat oxidation.
Following the study outlined above, we can assume that an acute bout of resistance exercise is sufficient enough to burn fat in the 40 – 45 minutes following training. Knowing this, it is safe to anticipate an overall significant loss of fat with continued training and we can assume that resistance exercise is beneficial for weight loss.