Best Exercise for Overweight Teens

JAMA Pediatrics published a research study on The Healthy Eating Aerobic and Resistance Training in Youth (HEARTY) that included 304 overweight teens between the ages of 14 to 18. All were given the same four weeks of diet counseling to promote healthy eating and weight loss before being randomly placed into four groups: 1) resistance training involving weight machines and some free weights; 2) only aerobic exercise on treadmills, elliptical machines and stationary bikes; 3) combined aerobic and resistance training; and 4) no exercise training.

The following results were recorded:
1. each type of exercise reduced body fat significantly and similarly.
2. all three exercise programs caused significantly more fat loss than in the diet-only control group.
3. the teens who completed at least 70 per cent of the study's exercise sessions (4x/week for 22 weeks), the percentage of body fat decreased significantly more in those who did combined aerobic and resistance exercise than in those who only did aerobic exercise. In addition, waist circumference decreased close to seven centimeters in the combined aerobic plus resistance exercise group, versus about four centimeters in the groups with only one type of exercise, with no change in those randomized to diet only.

Reference: University of Calgary. Research study analyzes best exercise for obese youths. Retrieved from the web on 9/27/14 at http://www.ucalgary.ca/utoday/issue/2014-09-23/research-study-analyzes-best-exercise-obese-youths

Strength Training in Maturing Female Athletes

Pediatric Physical Therapy published research on the longitudinal trajectories of lower extremity strength across maturational stages for a group of female student athletes. Recent studies have indicated growth during adolescences without strengthening the muscles may results in the development of risk factors for patellofemoral pain and anterior cruciate ligament injuries. The study looked at knee flexion, knee extension, and hip abduction strength in 39 female athletes over three years. 

The results indicated that knee extension strength increased while hip abduction and hamstrings-to-quadriceps ratio strength decreased from prepubertal to pubertal stages. 

The researchers concluded that preadolescence is an optimal time to institute strength training programs aimed toward injury prevention. 

Reference: Quatman-Yates, Catherine C et al. A Longitudinal Evaluation of Maturational Effects on Lower Extremity Strength in Female Adolescent Athletes. Pediatric Physical Therapy. Fall 2013 - Volume 25 - Issue 3.

Strength Training and GMFCS IV

Developmental Neurorehabilitation published a case study to evaluate functional strength training (4x/wee x 10 weeks) for a 9 year old child classified as a level IV according to the Gross Motor Function Classification System (GMFCS).  Data was collected using an isokinetic dynomometer, the Gross Motor Function Measure and the Timed Up and Go test at baseline, 5 weeks and 10 week post intervention.  The results indicated the following:

• improvements were found in hip, knee and ankle muscles strength
• increase in GMFM-88 score
• decrease in time for TUG test performance.

Reference:   Dos Santos AN, da Costa CS, Golineleo MT, Rocha NA. Functional strength training in child with cerebral palsy GMFCS IV: Case report. Dev Neurorehabil. 2013 Apr 25. [Epub ahead of print]

Resistance Training in Children

Pediatrics published a review of the research on resistance training in children and adolescents. The researchers concluded that the ability to improve muscle strength increases with age and maturation without noticeable advancement noted during puberty. The duration of the study and the frequency of performed sets had a positive outcome on improving muscle strength.

Reference: Behringer, Michael, vom Heede, Andreas, Yue, Zengyuan, Mester, Joachim
Effects of Resistance Training in Children and Adolescents: A Meta-analysis
Pediatrics 2010 126: e1199-e1210