The science of training: overload, adaptation and specificity
Your body adapts to the stress you give it.
What to do
- Progressive overload: gradually increase demands.
- Specificity: you get better at what you practice.
- Recovery: adaptation happens during rest.
- Reversibility: fitness fades without training.
- Aerobic training improves heart and muscle ability to use oxygen; strength training increases muscle strength and size.
Copy this prompt
Explain [principle] in plain English with one example from my plan [paste], and how to apply it safely.Check the bot's work
Sources below.
Questions
Can I trust the bot on training science?
Use it to plan and explain, then verify. Sources below.
Which bot works best?
Grok Bot, ChatGPT, Claude and Gemini all handle this prompt. Paste the same prompt into two and compare; disagreements show where to check a source.
Where these facts come from
- HHS: Physical Activity Guidelines for Americans, 2nd edition
- CDC: Adult activity, an overview
- CDC: Measuring physical activity intensity
- ACSM: Physical activity guidelines
- NIH National Institute on Aging: Exercise and physical activity
- NIH NHLBI: Physical activity and your heart
- ACOG: Exercise during pregnancy
- CDC: About sleep
This is general information, not medical advice. Talk with a doctor before starting or changing exercise if you have a health condition, are pregnant, take medication, or have symptoms. Stop and call 911 for chest pain, fainting or severe shortness of breath. Checked Oct 30, 2026.
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