Muscles don't grow while you're training. They grow while you recover from it. Rest isn't skipping. It's half the job.
The short version
- Give each set of muscles about 48 hours before working them hard again.
- Do a little more over time. That's called progressive overload.
- Aim for 7 to 9 hours' sleep. It's the best recovery tool there is, and it's free.
Training asks. Rest answers.
Training puts your body under a bit of stress. Recovery is when it adapts and comes back a little stronger. Skip recovery and you're just asking the same question louder. For beginners training the whole body, the American College of Sports Medicine suggests leaving around 48 hours between hard sessions for the same muscles.1 Monday, Wednesday and Friday works. Monday, Tuesday and Wednesday doesn't.
Progressive overload, in English
It means doing a little more over time, so your body keeps having a reason to change.1 One more rep. The next step up the press-up ladder. Five more seconds on the wall sit. A slightly heavier bag of shopping. Not all at once, and not every session.
Sleep
Adults need 7 to 9 hours.2 If you're getting five, no supplement on earth makes up for it. Same bedtime most nights, a dark room, phone out of reach, caffeine before lunchtime (chapter 13), and go easy on the late pints (chapter 12).
Mike Mentzer: right about some things
Mike Mentzer was a top American bodybuilder in the 1970s with a big idea he called Heavy Duty. His argument was that most people train far too much. Do very few sets, push every one as hard as humanly possible, then rest for days.3 He was clever, persuasive, and quite cross about it.
So was he right? Partly. Here's a fair verdict.
Where he was right
- Effort matters. You have to work hard enough to give your body a reason to change.
- Doing more over time matters.
- Rest matters more than most people think.
- Low volume works, especially for beginners. A set or two per exercise builds strength when you're new.1
Where his rules go too far
- Every set to total failure, where you can't do one more rep. It isn't needed. Stopping a rep or two short works about as well for most people,4 and for beginners it keeps your form tidy.
- Very long gaps between sessions leave progress on the table.
- More weekly work generally builds more muscle, up to a point.5
The verdict: his principles hold up better than his rules. Train hard, rest properly, keep adding a little. Just don't treat every set as a fight to the death.
Your rep for this chapter
Check your week: no two strength sessions on back-to-back days. Then set a bedtime alarm, not just a wake-up one.
All 18 chapters of Basic Training
Sources
1. Ratamess NA et al. Progression models in resistance training for healthy adults. American College of Sports Medicine position stand. Medicine and Science in Sports and Exercise. 2009;41(3):687-708.
2. NHS. Insomnia ("adults need 7 to 9 hours").
3. Mentzer M, Little J. High-Intensity Training the Mike Mentzer Way. McGraw-Hill; 2003.
4. Grgic J, Schoenfeld BJ, Orazem J, Sabol F. Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy: a systematic review and meta-analysis. Journal of Sport and Health Science. 2022;11(2):202-211.
5. Schoenfeld BJ, Ogborn D, Krieger JW. Dose-response relationship between weekly resistance training volume and increases in muscle mass: a systematic review and meta-analysis. Journal of Sports Sciences. 2017;35(11):1073-1082.