The top titans of exercise—resistance exercise and cardiovascular exercise—continue to duke it out for the title of best fitness protocol. When it comes to obese girls, researchers believe they have a champion: cardio.
To determine this outcome, the researchers recruited 44 obese girls, aged 12–18, and assigned them to RE, CE or a nonexercise control group for 3 months. Measures included body weight, waist circumference, oral glucose, insulin sensitivity, body fat, cardiorespiratory fitness, muscular fitness and more.
The exercise protocols consisted of three 60-minute sessions per week. Participants in the CE group wore heart-rate monitors and were instructed to achieve 60%–75% VO2peak. No information was provided as to the type of cardiovascular activity performed. The RE group completed 1–2 sets (8–12 reps per set) of leg press, leg extension, leg flexion, chest press, latissimus pull-down, seated row, biceps curl and triceps extension—all performed at 60% of 1-repetition maximum. Single sets of push-ups and sit-ups were also performed.
The girls were asked to maintain a “weight-maintenance diet” (55%–60% carbohydrate, 15%–20% protein and 25%–30% fat) throughout the 3-month intervention.
By the end of the study, neither exercise group had lost any weight; however, the cardio group did lose fat: “Compared with control, significant reductions in visceral adipose tissue and intrahepatic lipid, and improvement in insulin sensitivity were observed in the [CE] group, but not the RE group,” explained the study authors. “In obese adolescent girls, aerobic exercise, but not resistance exercise, is effective in reducing liver fat, visceral adiposity and improving insulin sensitivity independent of weight loss or calorie restriction.”
The study was published in the American Journal of Physiology—Endocrinology and Metabolism (2013; doi:10.1152/ ajpendo.00285.2013).