How does frequency affect recovery, controlling for intensity and volume?

Question

What exactly is the body's mechanism to recover from the stress of strength training and to adapt to greater loads, and how does frequency of training affect this mechanism?

For illustration, consider two people not on drugs:

• Person A squats 6x5, once every 3 days, with a weight that takes the last rep close to failure.

• Person B squats 2x5, every day, with a weight that takes the last rep close to failure.

Who gets stronger faster? Three possibilities are:

1. Person A gets stronger faster. After being stressed by tension and activation near maximal effort, muscles and the nervous system need a minimum amount of time (I've heard 48-72 hours) to recover fully. Stressing them again in that time interrupts the recovery process and voids it.
2. It makes no difference. Person B's muscles and nervous system take one third the time to recover from one third the stress of person A's workout. Both people are getting enough rest.
3. Person B gets stronger faster. Not only are both people getting enough rest, but:
   • he releases testosterone more often and therefore spends more time in an anabolic state.
   • his reps are higher quality, with better form and more explosiveness, because he's not fatiguing himself with so many sets in one session. Therefore, his average rep recruits muscle fibers more efficiently than person A's average rep, and he is less likely to injure himself.

Answer 1

The short answer is that Person A gets stronger faster.

The long answer is that it depends, because recovery is defined by different factors, mainly: gender, weight and muscle group. A 54 kg female athlete could squat 4 times a week and not be overtrained, but if a 200 kg male athlete deadlifts 4 times per week, his recovery will be greatly affected.

If you are looking to distribute your volume through the week, you must take care to perform a minimum number of sets to elicit a growth stimulus in each day. 2 sets of 5 may not be enough.

This is Prilepin's Chart, which gives you a minimum number of reps/sets to perform every training session to provoke a stimulus, and a maximum number to prevent overtraining. These numbers might seem low, but they are designed to avoid technical failure and, thus, preventing injuries.

There's a lot more to fatigue management than this. You need to take into account the phase in your training cycle (deloading or overreaching, etc), your gender, genetics, your age and many other factors.

I recommend you to google about Hristo Hristov's INOL index. Also, this is quite an informative read if you are interested in the subject of fatigue management: http://www.jtsstrength.com/articles/2016/02/29/47634/

Although, If you are a beginner or intermediate lifter, you can pick any cookie cutter program like 5/3/1 and go with it.