Effects of aerobic training, resistance training, or both on cardiorespiratory and musculoskeletal fitness in adolescents with obesity: the HEARTY trial

March 7, 2017

Angela S. Alberga, Denis Prud’homme, Ronald J. Sigal, Gary S. Goldfield, Stasia Hadjiyannakis, Penny Phillips, Janine Malcolm, Jinhui Ma, Steve Doucette, Rejeanne Gougeon, George A. Wells, and Glen P. Kenny.

Appl. Physiol. Nutr. Metab. 41: 255–265, 2016

Physical activity levels typically decline from childhood to adolescence. Adolescence is a critical period to prevent fitness declines associated with physical inactivity. Despite the well-known benefits of both aerobic and resistance exercise training on cardiorespiratory and musculoskeletal fitness in adults, the effects are less known in adolescents with obesity. This paper examines the effects of aerobic, resistance, and combined exercise training on cardiorespiratory and musculoskeletal fitness in adolescents with obesity.

Participants in the HEARTY trial (Healthy Eating Aerobic and Resistance Training in Youth) were post-pubertal (Tanner Stage 4-5) adolescents (N=304) aged 14-18 years with obesity (body mass index >95th percentile for age and sex or ≥85th percentile plus an additional diabetes risk factor). They participated in a 6-month intervention. All participants began in a 4-week supervised combined aerobic and resistance exercise training run-in program four times per week to familiarize themselves with the exercise program. If they attended 80% or more of exercise sessions, they were randomized to one of four groups for an additional 22 weeks: 1) Aerobic training alone, 2) Resistance training alone, 3) Combined training or 4) a non-exercise Control group. All four groups received guidance by a dietitian to reduce dietary intake by ~250kcal/day. Cardiorespiratory fitness was assessed by peak oxygen consumption and treadmill time in a graded maximal exercise test. Muscular fitness included the measurement of muscular strength on the leg press, bench press and vertical row using an 8-repetition maximum test and the use of the 2003 CPAFLA tests to perform additional measurements of muscular strength (hand-grip), endurance (push-ups), power (vertical jump) and flexibility (sit and reach).

Our key findings were: (1) Aerobic exercise training alone increased cardiorespiratory fitness by 9.2% and the number of partial curl-ups (abdominal muscular endurance) increased by 21.0%. (2) Resistance exercise training alone increased upper body muscular strength (bench press) by 37.9% and seated row by 21.4%. Lower body muscular strength (leg press) also increased by 73% and muscular endurance (push-ups) by 77.8%. (3) Combined aerobic and resistance exercise training showed improvements in cardiorespiratory fitness by 5.2% and muscular strength (leg press increased by 58.0%, bench press by 41.4%, seated row by 34.1%) and muscular endurance (push-ups increased by 70.0%). More marked improvements were seen in participants with higher exercise adherence.

This study showed that adolescents who attended the combined aerobic and resistance exercise sessions over a 6-month period improved their cardiorespiratory and muscular fitness more than aerobic training alone. Body weight did not change, although there were small decreases in percent body fat in all exercise training groups. This paper has the potential to influence how exercise is promoted for teenagers living with obesity. Our results suggest that teenagers with obesity can improve their fitness most with combined aerobic and resistance training even without changes in body weight. Thus, we recommend that combined exercise training should be promoted as a gateway for improving overall fitness rather than focusing on changing body weight in youth.

Reference
Angela S. Alberga, Denis Prud’homme, Ronald J. Sigal, Gary S. Goldfield, Stasia Hadjiyannakis, Penny Phillips, Janine Malcolm, Jinhui Ma, Steve Doucette, Rejeanne Gougeon, George A. Wells, and Glen P. Kenny. Effects of aerobic training, resistance training, or both on cardiorespiratory and musculoskeletal fitness in adolescents with obesity: the HEARTY trial. Appl. Physiol. Nutr. Metab. 41: 255–265, 2016

This article is a summary of an article published in Applied Physiology, Nutrition & Metabolism. If you intend citing any information in this article, please consult the original article and cite that source. This summary was written by Dr. Angela S. Alberga for the Canadian Society for Exercise Physiology and it has been reviewed by the CSEP Knowledge Translation Committee.