Program Design
The OPT model and acute variables
The OPT model has five phases: Phase 1 Stabilization Endurance (12-20 reps, 4/2/1 tempo, 0-90 s rest), Phase 2 Strength Endurance (8-12 reps, 2/0/2, 0-60 s), Phase 3 Hypertrophy (6-12 reps, 2/0/2, 0-60 s), Phase 4 Maximal Strength (1-5 reps, 4/2/1 or explosive, 3-5 min rest), and Phase 5 Power (1-10 reps, explosive tempo, 0-60 s rest, often a strength exercise superset with a power exercise).
Know the acute variables - repetitions, sets, intensity (% 1RM), tempo, rest interval, exercise selection, frequency, and duration - and how they shift across phases. Program design also rests on progressive overload, specificity, variation, and periodization, with the fitness-fatigue model explaining why training stress and recovery must be balanced. Warm-ups typically include SMR, static stretching, and cardiorespiratory work; cool-downs reverse the order.
Traps: matching a rep range to the wrong tempo or rest period; putting a beginner into Phase 4 or 5; confusing hypertrophy (Phase 3) with strength endurance (Phase 2); forgetting that power phases still include a strength exercise. Worked example: a prescription of 12-20 reps at 4/2/1 tempo with 0-90 seconds rest is Phase 1 - even if the exercise is a squat, the phase is defined by the variables, not the movement.