By rest, we are talking about the time between sets, not recovery per se.
What actually happens while you rest?
The human body is one big bad complex bag of hormones, so I’m just going to give a basic overview of energy systems that is vastly over-simplified, if you want more info on this, use google.
Each muscle has a store of ATP it can break down for energy, and a store of CP it can break down to create more ATP quickly. These two energy stores last for about 8 seconds of near-maximal effort. This is the energy system that tends to be most important to consider for strength and power training. This system is quick to be depleted but it doesn’t take very long to recover; your peak power output will return to >90% after 3 minutes rest.
As the ATP-CP system is kicking in, the lactate energy system starts kicking in to begin restoring the ATP and provide energy for slightly longer term exercise. This is the energy system commonly associated with lactic acid and anaerobic training. It is thought to be the phase in which you start to feel the burn, and which fatigue is derived from acidosis of the muscles.
Lastly you have the aerobic energy system kicking up a notch, using oxygen to assist in restoring ATP. It lasts the longest but is hella slow.
How long is traditionally recommended for your goal?
Maximal Strength or Power – 2-5 minutes, to allow for maximum recovery to maintain intensity and volume.
Hypertrophy Training – 30-90seconds, to increase the expression of anabolic hormones.
Endurance Training – <30 seconds, maintain the physiological stress on the body to create adaptation
How does rest actually affect each set?
Besides all the physiological effects above, fatigue is also a mental phenomenon, so how you feel is very important.
When both sorts of fatigue are considered, shorter rests will decrease the number of subsequent reps you can perform, increase the potential for form breakdown, decrease the speed of reps, increase the amount of growth hormone and increase the pump to the muscles. It will also place greater demands on the system as a whole, challenging your conditioning.
When the rests are longer, you can maintain intensity better with reps closer to your max, maintain form better, maintain speed of reps (i.e force production), but it may decrease the hormone response beneficial for muscle growth.
For strength and power training, what tends to be most important is the volume of practice you get at high intensities, with good form. Longer rest lets you keep the number of reps you can perform at a given intensity higher, and perform them with greater speed and form. You should rest not only until your energy systems have restored your ability to perform the exercises, but also long enough so that you aren’t mentally fatigued such that your intensity or form will suffer. Get into the right mindset and then kill it.
For hypertrophy training, the overall volume * intensity is what matters, so even if your intensity and number of reps is dropping from set to set, if you get in lots of reps at medium-heavy weights, the body will tend to respond. Thus you can get away with shorter rests to make for a more efficient workout. That’s not to say that longer rests won’t give you hypertrophy, and a mix of heavy, long-rest volume and medium short rest volume is often recommended.
Rest and Paired/Grouped Sets
As long as your paired/grouped sets are complimentary and use different motor patterns/muscle groups, each exercise’s recovery won’t interfere with the other’s to a great degree. Take long enough between each exercise to make sure you aren’t gassed and have the mental focus to perform each exercise well. With the rest between exercises and the exercises themselves, it should add up to enough rest for full recovery between sets of the same exercise.
Even circuit training, with short rests between exercises (30-60 seconds) and intelligent spacing of the exercises can be an effective way to train as a beginner. It won’t be as efficient for your effort, but is a good way to save time. This method may lose a lot of its effectiveness as you become more advanced (or even more acclimatised than 3 sessions…)
Rest and Conditioning
LISS conditioning or traditional forms of cardiovascular exercise aren’t the only way to cause adaptations in the cardiovascular system and the majority of specific adaptations to that style of training are in the peripheral systems (mainly the musculoskeletal system). Heavy resistance training with some non-trivial training density will causes plenty of adaptations to your cardiovascular system. Keeping your workouts intense and dense will challenge your conditioning and increase your conditioning to meet that challenge. These adaptations are quickly come upon, but also quickly lost, if you don’t maintain intensity, you will lose your level of conditioning.
How short a rest you have (and how much it affects your ability to do the sets) will depend on how conditioned you really want or need to be. It doesn’t take very long to be conditioned for a specific event, so killing yourself into a sweating heaving puddle to “feel” like you’ve worked out, isn’t necessarily making you more fit.
If you can complete your workouts in a reasonable amount of time, you are conditioned enough for bodyweight resistance training.
If you need to rest for ages between sets because you’re gassed and your workouts end up taking forever, maybe it’s time to HTFU and work hard for once.
Bigger compound exercises are going to take longer to systemically recover from than smaller exercises, and pairing sets (thus reducing overall rest time) will get you breathing heavier than straight sets.
What about splitting up the set throughout the day?
Splitting up your workout throughout the day (i.e taking really long rest breaks) is obviously going to let your energy systems fully recover between sets, which would seemingly mean you could workout at the maximum intensity. Consider how well you could get into the mindset of performing intensely for a very short block multiple times a day, and how much warm-up and prep work you’d need to do each time to effectively and safely do the exercise.
Some people and some exercises will be more suited to this sort of training than others, consider this style of training carefully. It is a very accessible tool for a lot of bodyweight movements, as most moves require no to very little equipment or set up, so the opportunity to train is much more plentiful.
For strength training, doing individual sets for one or two exercises spread throughout may be a good way of busting a plateau, if you can perform it with a short warm-up and do it intensely and mindfully.
For hypertrophy, I wouldn’t recommend doing lots of spread sets throughout the day as an early option, but splitting a session into two chunks may be a good way to keep intensity in the second half.
We will cover this topic in more depth in a discussion about training and exercise frequency (including GtG).
Using intra-set rest
Often called “Cluster Sets” or “Rest Pause Training” is taking a very short break, usually 5-30 seconds, between repetitions or small groups of repetitions to make up one set. For example, performing a single rep, pausing for 5-10 seconds before performing the next rep, and so on until you have completed the desired number of reps. Or performing 3 reps, pausing for 5 seconds, 2 reps, pausing for 5 seconds, 2 reps; you end up performing 7 reps, where you may have only been able to perform 5 reps in a straight set.
This is an interesting way to boost the volume in your sets while maintaining a high intensity (and efficiently too, as you aren’t adding much extra time to your overall workout), which can be particularly useful for bodyweight training, where you may lack the granular control over intensity like lifting weights, making hitting that sweet spot of intensity and volume difficult.
Other than boosting the overall volume, training like this has some interesting effects. Going to or near failure is often cited as being a very powerful contributor to the factors that boost hypertrophy; with this style of training, you may end up going near failure 2-4+ times in quick succession, a powerful metabolic and hormonal trigger for hypertrophy. The short breaks also can give you a mental edge, allowing you to reset and refocus, potentially boosting form and intensity. Performing an exercise you can’t perform for 2 reps in a row with can be difficult to build the volume if you’re resting for maximum recovery every set, rest pause can help you double or triple the size of these sets.
How can I incorporate this into my training?
- Forever increasing the rest between sets to keep on progressing doesn’t necessarily mean you are still improving. If you can’t perform more reps in your subsequent sets than you could a few weeks ago with the same rest, you probably haven’t improved.
- Decreasing the rest between sets (increasing training density) can increase the intensity and is an alternative to moving on to another progression to progress, make sure to take advantage of this practice by, in later workouts, extending your rest but increasing your volume and/or intensity.
- If you’re advanced enough that playing with your rest is an important factor in your training, start tracking it and being consistent with how you approach it.
- Pick an exercise where your form breaks down quickly and try doing some rest pause sets, refocussing in the rest to being super strict with your form.
I’m a beginner, how do I use this info?
As a beginner, you will gain muscle by thinking about exercise hard enough. Don’t worry about the hormonal effect and all that crap. Your main goals during your initial training is to learn the moves and get stronger at them, so when you exercise, you’re having a bigger effect on your muscles (and metabolism). Take longer breaks than shorter, and long enough that you’re mentally prepared for the exercises.
If you feel gassed doing all the exercises, don’t just keep on extending your breaks, learn that it may suck the first few sessions, but it will improve quickly. Take 2-4 minutes max.