NASM-YES cheat sheet

Peak height velocity (PHV): the age of fastest statural growth; in boys roughly 14 years, in girls roughly 12 years, with wide individual variation of about ±2 years.

The pubertal growth spurt is driven by the GH–IGF-1 axis plus sex steroids; estrogen drives the female spurt and also promotes epiphyseal closure, while testosterone drives male growth and lean mass accrual.

During the adolescent growth spurt, bone lengthens before muscle-tendon units adapt, producing transient declines in flexibility and relative strength (the 'adolescent awkwardness' window).

Youth resistance training is safe and effective when supervised and technique-focused; injury risk in supervised programs is lower than in many popular team sports.

Strength gains in pre-PHV children are driven largely by neural adaptations (motor unit recruitment, intermuscular coordination); hypertrophy becomes a major contributor after PHV.

Aerobic fitness is trainable in youth, but children show a blunted training response versus adults in absolute VO2max; relative improvements are comparable.

Children thermoregulate less efficiently than adults (higher surface-area-to-mass ratio, lower sweating rate), so heat stress and dehydration risk rise faster during exercise.

Bone responds to impact and ground-reaction forces: plyometric and jumping activities during growth stimulate osteogenesis, provided volume is progressive and landings are controlled.

Physical literacy (competence, confidence, motivation, knowledge) underpins long-term adherence; skill competence in childhood predicts adolescent activity participation.

WHO/AAP baseline: children and adolescents aged 6–17 should accumulate at least 60 minutes of moderate-to-vigorous physical activity daily, mostly aerobic, across the week.

Vigorous-intensity aerobic activity, plus muscle- and bone-strengthening activities, should each occur at least 3 days per week in the 6–17 age group.

Resistance training guidelines: begin with light loads and high technical proficiency; 1–3 sets of 8–15 repetitions across 1–3 sessions per week is a common entry progression.

Load progression rule: increase resistance by roughly 5–10% only after the client completes the prescribed sets/reps with sound technique in consecutive sessions.

Adults' 1RM percentage-based loading is inappropriate for youth; use repetition-maximum or effort-based loading (e.g., 10–15RM) to control intensity.

Rest between sets and between training days must be sufficient for recovery; youth should not perform maximal or near-maximal lifts, and 1RM testing is generally avoided.

Aerobic prescription for youth uses moderate-to-vigorous intensity (RPE-based talk test) for 20–60 minutes, 3–7 days per week, progressed from shorter bouts.

Flexibility training is most productive after a warm-up or in a separate session; static stretches are typically held 15–30 seconds for 2–4 repetitions per muscle group.

Screen-time and sedentary behavior limits (commonly ≤2 hours recreational screen time daily) are separate from, and additive to, the 60-minute activity target.

Training-age model: classify clients by months of structured training rather than chronological age; beginner = 0–6 months, intermediate = 6–12 months, advanced = 12+ months of consistent work.

Maturation screening: use PHV timing (predicted from height measurements or maturity offset) to decide whether to prioritize movement competency (pre-PHV) or strength/power progressions (post-PHV).

Fundamental movement skills (squat, hinge, push, pull, brace, rotate, land) are the prerequisite screen; do not load a pattern the client cannot perform unloaded with control.

Program design sequence: movement competency → strength → power; plyometrics are introduced only after the client demonstrates adequate landing mechanics and lower-body strength.

Youth clients need shorter attention spans and lower training tolerances; sessions of roughly 30–60 minutes with frequent variation and game-based elements improve adherence.

Neuromuscular training warm-up programs (balance, landing, cutting, strength, plyometrics) reduce sports-related lower-extremity injury risk in adolescent athletes.

Growth-related conditions to monitor include Osgood-Schlatter and Sever's disease; manage with load modification rather than complete rest where tolerated.

Psychosocial development matters: autonomy-supportive coaching, mastery climate, and effort-based feedback support intrinsic motivation and long-term retention in adolescents.

Communication and consent: involve parents/guardians in goal setting and screening, and adapt cuing language to the client's cognitive stage (concrete vs. abstract reasoning).