People who are battling with their weight but are unable to do aerobic exercise can still see results at the gym, with new research finding that resistance training - or lifting weights - can promote weight loss.
Despite the commonly held belief that aerobic exercise is essential for weight loss, a recent study led by researchers at Edith Cowan University (ECU) - and conducted at the Exercise Medicine Research Institute (EMRI) - found resistance training can also have positive results, in conjunction with reducing calorie intake.
Strength training, or resistance training, involves physical exercises that are designed to improve strength and endurance. The style of training is often associated with lifting weights, but can also incorporate a variety of techniques such as callisthenics, isometrics and plyometrics. For example, resistance training could include free weights such as dumbbells, barbells and kettlebells; medicine balls or sandbags; or weight machines - adjustable devices with handles or pads attached either to weights or hydraulics.
Lead researcher and PhD student Pedro Lopez said the findings demonstrate that resistance training can have a significant effect on fat mass, muscle mass and weight loss.
"Usually when we talk about obesity, body composition or weight loss, we only hear about aerobic exercise," he said.
"This paper shows we can use resistance training and achieve meaningful effects with a diet based on caloric reduction. We can reduce body fat percentage, whole-body fat mass, body weight and BMI.
"If you're comparing the literature, these effects are similar to aerobic exercise with caloric restriction in adults who are overweight or obese."
The study found that interventions involving resistance training and caloric restriction were the most effective for reducing body fat percentage and whole-body fat mass, compared to groups without any intervention. Significant results and reductions in body weight were also observed in those who completed programmes that combined resistance training and aerobic exercise.
An exercise programme based solely around resistance training was found to be the most effective for increasing lean mass compared with no training controls, the researchers said, with the results consistently observed across different age groups and sexes.
The study, which was first published in the journal Obesity Reviews earlier this year, concluded there is evidence that resistance-based exercise is effective and should be considered as part of multi-component programmes for overweight or obese adults - in conjuction with caloric restriction.
"Considering the similar effect on fat and weight loss and unique effect on lean mass, resistance training rather than aerobic exercise alone should be considered within any multicomponent fat loss prescription for individuals with overweight/obesity," the researchers said.
"Resistance-based training is an effective option… for targeting fat and weight loss while maintaining lean mass in individuals who are overweight/obese."
Lopez said it's important that people battling obesity have options beyond aerobic exercise in their journey to losing weight.
"This group may be uncomfortable by the prospect of 30 or 40 minutes on a treadmill or a bicycle," he noted.
"They can injure knees, joints, ligaments and more because they have to carry their whole body weight during a lot of aerobic exercises."
Resistance training also caters to other factors that are important for weight loss, Lopez added - such as building and preserving muscle mass.
"The study also showed resistance training was effective in avoiding losing muscle mass when lowering the number of calories being consumed," he said.
However, Lopez stressed the study was not a comparison between aerobic and resistance exercise. Regardless of which people chose to perform, they would also have to cut down on the calories to see positive results.
"If you want to lose weight, you have to reduce your calorie intake," he reiterated.
According to the US National Academy of Sports Medicine, weight training is an excellent way to burn calories. Certain exercises require the whole body to engage, torching calories and building muscle simultaneously. Maintaining and building muscle mass is a benefit to someone trying to lose weight because muscle tissue burns more calories than fat.
As reported by the New York Times, muscle is metabolically active and burns calories - so adding muscle mass by lifting weights should increase the person's energy expenditure and resting metabolic rates. After six months of heavy lifting, for example, muscles will burn more calories simply because they are larger.
