What causes newbie gains? The science behind rapid strength growth
Dr. Bruno Rodriguez, DPT, CSCS: Strength, Recovery, and Physical Therapy Expert
Dec 23, 2025 · 10 min read
Newbie gains are caused primarily by rapid nervous-system adaptation—especially improved motor learning and motor-unit recruitment—so most strength increases in the first 4–8 weeks occur before substantial new muscle is built, and untrained lifters can gain more than 5× as much strength over 21 weeks as trained lifters. Here’s how this short 6–12 month “hyper-responsive” window ...