Weightlifting, also known as resistance training, has been practiced for centuries as a way to build muscle strength. Research shows that resistance training, whether done via bodyweight, resistance bands or machines, dumbbells or free weights, not only helps us build strengthbut also improves muscle size and can help counter age-related muscle loss.
More recently it has become popular among those looking to lose weight. While exercises like running and cycling are indeed effective for reduce body fatthese activities can simultaneously decrease muscle size, resulting in weaker muscles and greater perceived weight loss, as muscle is denser than fat. But unlike endurance exercises, evidence shows resistance training not only has beneficial effects on reduce body fatthis too increases muscle size and strength.
The “afterburn effect”
When we exercise, our muscles need more energy than when we are resting. This energy comes from our muscles’ ability to break down fats and carbohydrates (stored in muscle, liver and adipose tissue) using oxygen. So during exercise we breathe faster and our heart works harder to pump more oxygen, fats and carbohydrates to our muscles.
What is less obvious, however, is that once exercise is over, oxygen consumption actually remains high in order to restore muscle to their resting state by breaking down stored fats and carbohydrates. This phenomenon is called excessive post-exercise oxygen consumption (EPOC) – although more commonly referred to as the “afterburn effect”. It describes how long oxygen consumption remains elevated after exercise to help muscles recover.
The extent and duration Afterburn effect is determined by the type, duration and intensity of exercise, as well as fitness level and diet. Longer duration exercise that uses multiple large muscles, performed until or near fatigue, results in a higher and longer lasting afterburn.
High Intensity Interval Training (HIIT) and High Intensity Resistance Training are the most efficient to raise the afterburner in the short and long term. The reason HIIT-type exercises are considered more effective than steady-state endurance exercises is because of the increased fatigue associated with HIIT. This fatigue results in a greater amount of oxygen and energy needed during a extended period to repair damaged muscles and replenish depleted energy stores. As such, resistance exercise is an effective way to lose excess fat due to the high calorie cost of the actual workout and the “afterburn effect”.
Long term fat loss
Resistance training can also be effective for long-term weight control. This is because muscle size plays a major role in determining resting metabolic rate (RMR), which is the number of calories your body needs to function at rest. The resting metabolic rate represents 60-75% of total energy expenditure in people who do not exercise, and fat is the favorite energy source at rest.
Increasing muscle size through resistance training increases RMR, thus increasing or maintaining fat loss over time. A review of 18 studies found that resistance training was effective at increased resting metabolic ratewhile aerobic exercise and combined aerobic and resistance exercise were not as efficient. However, it is also important to control calorie intake in order to lose fat and maintain fat loss.
Resistance training exercises should involve the largest muscle groups, use full-body exercises performed while standing, and should involve two or more joints. All of these forces the body to work harder, thus increasing the amount of muscle and therefore the RMR. An effective resistance training program should combine intensity, volume (number of exercises and sets), and progression (increasing both as you get stronger). The intensity should be high enough that you feel challenged during your workout.
The most effective way to do this is to use the rep maximum method. For the purpose of fat loss, this should be done between six and ten repetitions of an exercise with resistance that causes fatigue, so you can’t comfortably do another full rep after the last one. Three to four sets, two or three times a week for each muscle group is recommended.
The rep-max method also ensures progression, because the stronger you get, the more resistance or load you’ll need to increase to induce fatigue by the tenth rep. Progression can be achieved by increasing resistance or intensity so that fatigue occurs after performing fewer reps, say eight or six.
Resistance training aids in excess fat loss by both increasing post-exercise afterburn and increasing muscle size, thereby increasing the number of calories we burn at rest. Combining it with a healthy diet will only further increase the loss of excess body fat – and may bring other positive health benefits as well.
