1. Experience accelerated physical development marked by increases in weight, height, heart size, lung capacity, and muscular strength;
2. Mature at varying rates of speed. Girls tend to be taller than boys for the first two years of early adolescence and are ordinarily more physically developed than boys;
3. Experience bone growth faster than muscle development; uneven muscle/bone development results in lack of coordination and awkwardness; bones may lack protection of covering muscles and supporting tendons;
4. Reflect a wide range of individual differences which begin to appear in prepubertal and pubertal stages of development. Boys tend to lag behind girls. There are marked individual differences in physical development for boys and girls. The
greatest variability in physiological development and size occurs at about age 13;
5. Experience biological development five years sooner than adolescents of the last century; the average age of menarche has dropped from 17 to 12 years of age;
6. Face responsibility for sexual behaviour before full emotional and social maturity has occurred;
7. Show changes in body contour including temporarily large noses, protruding ears, long arms; have posture problems;
8. Are often disturbed by body changes:
• Girls are anxious about physical changes that accompany sexual maturation;
• Boys are anxious about receding chins, cowlicks, dimples, and changes in their voices.
9. Experience fluctuations in basal metabolism which can cause extreme restlessness at times and equally extreme listlessness at other moments;
10. Have ravenous appetites and peculiar tastes; may overtax digestive system with large quantities of improper foods; and
11. Lack physical health; have poor levels of endurance, strength, and flexibility; as a group are fatter and unhealthier.

Young adolescence is a pivotal time of physical, intellectual, social and emotional development. Middle school learners experience more development at this age than any other stage in their lives with the exception of infancy.

Middle school learners experience a wealth of physical changes. Although girls are often more physically advanced than boys, both boys and girls experience disproportionate bone and muscle growth that results in feelings of discomfort, awkwardness and restlessness. Students also experience frequent hormonal imbalances that lead to hunger, excitement or lethargy.

Physical development refers to bodily changes including growth, improved gross and fine motor skills, and biological maturity. In early adolescence, the young adolescent body undergoes more developmental change than at any other time except from birth to two years old. Developmental growth includes significant increases in height, weight, and internal organ size as well aschanges in skeletal and muscular systems with growth spurts occurring about two years earlier in girls than boys. Because bones are growing faster than muscles, young adolescents often experience coordination issues. Actual growing pains result when muscles and tendons do not adequately protect bones. Fluctuations in basal metabolism cause these youth to experience periods of restlessness and lassitude. Young adolescents, particularly European-American youth, are often physically vulnerable due to improper nutrition, poor physical fitness, and health habits as well as high-risk behaviours
such as alcohol or drug use and sexual activity.

Puberty, a phase of physiological change triggered by the release of hormones, begins in early adolescence. The onset of puberty is an intense developmental period with hormones signaling the development of primary sex characteristics (genitalia) and secondary sex characteristics (e.g., breast development in girls; facial hair in boys). Girls tend to mature one to two
years earlier than boys. The increased adrenal hormone production affects skeletal growth, hair production, and skin changes. These highly visible changes and disparate rates of maturity cause many young adolescents to feel uncomfortable about differences in their physical development.

The young adolescent brain undergoes remarkable physical development. While brain size remains relatively unchanged, researchers report significant changes within the brain. During early adolescence, synaptic pruning is actively restructuring the brain’s neural circuitry. The prefrontal cortex an area of the brain that handles executive functions such as planning, reasoning, anticipating consequences, sustaining attention, and making decisions continues to develop. Additionally, gender-specific differences are evident in young adolescent brains.

Physical development often affects young adolescents’ emotional/psychological and social development. Practitioners (eg, teachers or guidance counsellors) and parents can alleviate young adolescents’ concerns about physical development by explaining that these changes are natural and common. Adults can provide accurate information, respond to questions, and encourage young adolescents to consult credible resources.