Many position stands and review papers have refuted the myths associated with resistance training (RT) in children and adolescents. With proper training methods, RT for children and adolescents can be relatively safe and improve overall health. The objective of this position paper and review is to highlight research and provide recommendations in aspects of RT that have not been extensively reported in the pediatric literature. In addition to the well-documented increases in muscular strength and endurance, RT has been used to improve function in pediatric patients with cystic fibrosis and cerebral palsy, as well as pediatric burn victims. Increases in children's muscular strength have been attributed primarily to neurological adaptations due to the disproportionately higher increase in muscle strength than in muscle size. Although most studies using anthropometric measures have not shown significant muscle hypertrophy in children, more sensitive measures such as magnetic resonance imaging and ultrasound have suggested hypertrophy may occur. There is no minimum age for RT for children. However, the training and instruction must be appropriate for children and adolescents, involving a proper warm-up, cool-down, and appropriate choice of exercises. It is recommended that low- to moderate-intensity resistance exercise should be done 2-3 times/week on non-consecutive days, with 1-2 sets initially, progressing to 4 sets of 8-15 repetitions for 8-12 exercises. These exercises can include more advanced movements such as Olympic-style lifting, plyometrics, and balance training, which can enhance strength, power, co-ordination, and balance. However, specific guidelines for these more advanced techniques need to be established for youth. In conclusion, an RT program that is within a child's or adolescent's capacity and involves gradual progression under qualified instruction and supervision with appropriately sized equipment can involve more advanced or intense RT exercises, which can lead to functional (i.e., muscular strength, endurance, power, balance, and co-ordination) and health benefits.

The evaluation of training load and effectiveness in elite athletes is difficult. We determined the effect of a four-week training camp on changes in self-assessment physical conditioning scores, fitness and circulating IGF-I in elite Israeli handball players during their preparation for the 1999 World Junior Handball Championship. Training consisted of two weeks of intense training followed by two weeks of relative tapering. Fitness was assessed by field test measurements of 1000-m run, 4 x 10-m shuttle run and vertical jump. Serum IGF-I levels were measured by immunoradiometric assay. Measurements were performed before, after two weeks, and at the end of training. Training resulted in a significant (p < 0.05) improvement in the results of the 4 x 10-m run, 1000-m run and vertical jump. Changes in the self-assessment physical conditioning score showed a bi-directional pattern. After two weeks of training the players reported decreased physical conditioning scores, with return to basal levels after four weeks. Similarly, circulating IGF-I decreased significantly after two weeks, and returned to basal levels after four weeks of training. We found a significant correlation between changes in circulating IGF-I, and self-assessments of physical conditioning scores (r = 0.71, p < 0.001). Intensive training resulted in a decrease, while tapering was associated with an increase in IGF-I levels. These changes were accompanied by parallel changes in subjective physical conditioning self-assessments.

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