How do daily push-ups (as in army bootcamp) lead to muscle growth

Question

Accepted knowledge in these communities and with most trainers is recovery days are when the body grows. And that sans recovery days you're only breaking down muscle fibers without letting them grow back, eventually leading to negative results.

Yet, military bootcamps make recruits do a large number of push-ups everyday. And all recruits end up with much bigger muscles by the end of it.

How does that work?

Answer 1

Accepted knowledge in these communities and with most trainers is recovery days are when the body grows.

Yes, but not by necessity. The days following a bout of resistance training are when muscular growth occurs. Most people don't train the same muscle group multiple days in a row, so as a result of their scheduling, the growth is happening when the muscle is being rested. But that doesn't mean that muscle growth can only occur at rest.

While there is evidence that excessive training volumes are detrimental to muscle growth, there is no evidence to suggest that training during the muscle growth period interrupts muscle growth. So, consider the following three training programs:

1. You do pushups twice per week, doing seven sets to failure per session, for a total of 14 sets per week.
2. You do pushups every day, doing two sets to failure per session, for a total of 14 sets per week.
3. You do pushups every day, doing seven sets to failure per session, for a total of 49 sets per week.

Training programs 1 and 2 have the same volume, so there's no reason to believe that program 2 would give worse results, even though it has no rest days. Training program 3 also has no rest days, but it has drastically excessive volume, and so could result in reduced performance and increased injury risk.

And that sans recovery days you're only breaking down muscle fibers without letting them grow back, eventually leading to negative results.

You don't damage all of your muscle fibers in a training session, and you don't use 100% of your muscle fibers when a muscle contracts, so the body still has plenty to work with and isn't likely to re-damage the same muscle fibers again.

Answer 2

Don't forget that the people in question are young, healthy and their goal is not optimal muscle gain.

• Young bodies repair damage faster. Presumably that's the most relevant reason.
• Their goal is to survive the bootcamp, not to optimize growth. The goal of their superiors probably is not to have them develop thick arms, but to train discipline and the ability to suffer through hard times. So even though they end up with thick arms, doing it differently might get the same result quicker.
• One part why we (normal, non-military bootcamp people) care about recovery is that it just feels awful to be always in a non-recovered state, even if it's not so bad that the body is breaking down. This presumably is also not high on the scale of motivation in the army setting.
• Training and recovery works on a scale, it's not an "on/off" thing. Assume your body is like a battery - it has a capability going from 0% to 100%, with 0% being where you fall over in a coma, and 100% where you are bristling with energy. All activities either increase or decrease the capacity. As a normal human, it feels great to be in the upper parts - regular folks, even avid weight practicioners, would probably structure their load to always be more energetic than not. Again, in an army setting, this just does not apply - bootcamps are amongst others designed to weed out the unfit; people who cannot stomach weeks of existing in the lower ranges of capacity are not the best to send into a war...
• With load, the risk of injury increases. For someone training with a goal of muscle gain, getting injured is by far the worst that can happen, as it forces you to take a break for weeks or even months, in which your body will slowly lose those precious gains. Again, in a selective bootcamp setting, running the load very high spits out those folks who are prone to injury, or oppositely confirms those that are "tough" and likely to not get a simple muscle strain when on the battlefield...

I am not saying that all of this is great, but I can pretty well imagine that it is the thinking that leads to the practice. I do not know whether there is actual, publicly available army doctrine which formalizes this in regards to training their soldiers to be stronger. But you easily do find doctrine on using this as punishment, so it just seems to go with the territory...

Answer 3

As I see it there are two separate issues in your question:

High frequency

Is doing 2 sets 5 x a week better or worse than 5 set 2 x a week?

The answer seems to be: for advanced trainees higher frequency is better. For beginners to intermediate trainees it does not matter. Only total volume matters. However doing 10 sets 1 x a week is probably not as good as doing 5 sets 2 x a week since there seems to be a limit on how many useful set you can do per workout. (1)

High repetition

Is doing 25 push-ups as efficient as doing 5 reps of bench press?

A study has found that if both are taken to failure they should be equal. However that fails to take into account that higher repetitions leads to more cortisol produced. "Excessive volume is the #1 enemy of the natural trainee." (2)

In conclusion I think that doing push-ups 5 x a week may work if you take each set close to failure and especially if you add weight or use harder variations of push-ups and do not do too many sets each day. However I still think this style of training is less effective than heavy barbell training.

For a program that uses this style of training: 3).

(1) Full Body 5x Per Week: Why High Frequency Training Is So Effective

(2) Why high volume is not the answer for hypertrophy

(3) My Foolproof Calisthenics Template