Table of Contents
In Lesson 4 we discussed definitions of various terms and concepts related to resistance training. This covered how to describe individual repetitions, sets, repetition tempo, exercise range of motion, training to failure, rest periods between sets, and training frequency, among other aspects of training. Now that we understand these concepts we will discuss them in greater detail. In this lesson we will look at how the research suggests to apply these concepts for effective resistance training program design. I have compiled these recommendations in an infographic at the bottom of this lesson.
Note: There have been some overarching reviews published that attempt to compile much of this literature into general recommendations.
A 2021 systematic review and meta-analysis (SR/MA) of 119 studies including ≥6 week resistance training trials in adults evaluated the impact of different moderators of strength gains and hypertrophy in resistance training.(Polito, 2021) Most of these trials included relatively untrained individuals. Findings include:
- When considering load, repetitions, failure vs non-failure, sets per exercise, weeks of training, training frequency, rest intervals, and periodization, the only variables that were significant were:
- Young adults: non-periodized training yielded better strength outcomes than periodized training.
- Older adults: non-failure training, >12 week programs, ≥3 days per week frequency, and non-periodized training yielded better strength outcomes while ≥3 days per week frequency also yielded better hypertrophy outcomes.
- The table below includes their recommendations for best outcomes:
A 2021 position statement regarding how to maximize hypertrophy in athletic populations provides the following recommendations(Schoenfeld, 2021a):
- Load: A wide spectrum of rep ranges can yield comparable results and employing a variety may yield optimal outcomes. Moderate rep ranges (ie, 6-15) may be most practical as higher rep ranges can increase sensation of discomfort and lower rep ranges can prove more taxing on one’s joints.
- Volume: 10 sets per muscle group per week is a general minimum with potential benefits to higher amounts. One can consider increasing the number of sets per muscle group ~20% over a 4 week training cycle.
- Frequency: If weekly sets are equivalent then training frequency seems less relevant. However, one should likely limit each session to 10 sets per muscle group and thus ≥2 sessions per muscle group per week are needed if one intends to include >10 sets per muscle group per week.
- Rest intervals: One should rest at least 2 minutes between sets with multi-joint exercises while 60-90 seconds rest between sets is appropriate for single-joint and less taxing machine-based exercises.
- Exercise selection: One should include multiple exercises per muscle that utilize different planes/angles of pull and utilize the muscle in different ways. One should include a combination of multi- and single-joint exercises and when applicable preferentially work muscles at longer lengths. Free weight exercises that require complex movement patterns should be performed regularly while less complex exercises (ie, single-joint or machine exercises) can be rotated in one’s training program more frequently. Of note, I discuss exercises in Lessons 9-12.
- Set end point: Novice lifters can avoid failure while more experienced lifters will likely benefit from occasionally training to failure, potentially in a periodized fashion. Older lifters, however, should train to failure less frequently due to greater difficulty recovering from exercise sessions. Additionally, failure is better utilized on single-joint and machine-based exercises.
The above recommendations are a great starting point and one can make a lot of progress following them. The first set of recommendations doesn’t really tease apart differences between beginners and people with more resistance training experience, while the second set is tailored towards hypertrophy increases in athletic populations, not strength gains or complete beginners. Thus, I will evaluate all of the literature more comprehensively below.
Effective rep ranges for hypertrophy and strength adaptations
Historically many people believed that lower rep ranges were better suited for strength, medium rep ranges were better suited for hypertrophy, and higher rep ranges were better suited for muscular endurance. This is likely still the most prevalent view in the general public; additionally, many people also believe higher rep ranges “tone” the muscles. However, more recent research no longer supports these viewpoints.
Note: I placed the word “tone” in quotes because in reality the concept of toning a muscle is largely a myth. On a technical level there is some nuance here but practically speaking to change the appearance of a muscle you can either:
- make the muscle bigger (via skeletal muscle hypertrophy)
- lose the fat covering the muscle to make it more visible
- alter the amount of glycogen within the muscle
- “pump” up the muscle with repetitive contractions to induce temporary fluid accretion
- alter the skin overlying the muscle (ie, get a tan)
- alter the lighting in the room
Actual “toning” boils down to building up the muscle and losing the fat that covers it.
What the research suggests
A 2020 meta-analysis (MA) including 5 studies found no difference in results for skeletal muscle hypertrophy when comparing protocols including training between 30-90% of one’s one-rep maximum (1RM) or up to a 30 rep max.(Grgic, 2020) However, only one of these studies included participants with prior resistance training experience; additionally, the only study including women did actually find a benefit to using a higher load. A slightly older systematic review (SR) and meta-analysis (SR/MA) examined the impact of high vs low load resistance training on both hypertrophy and strength adaptations. This included 21 studies and found no evidence indicating differences with the exception of 1RM testing (higher loads benefited 1RM testing).(Schoenfeld, 2017a) Of the 21 studies, only 3 included previously resistance-trained subjects and only 7 included women. All studies had subjects train to failure.
A 2021 SR and network MA also examined studies where sets were taken to failure.(Lopez, 2021) Here 7 of 28 studies included people with prior training experience. There was no difference in hypertrophy with high (≥80% 1RM), moderate (60-79% 1RM), or low (<60% 1RM) loads. There was a benefit for strength with high and moderate loads compared to low, and a trend of benefit with high loads compared to moderate. A separate 2021 SR/MA included studies with and without training to failure; most studies included untrained participants.(Refalo, 2021) Similar to the prior research, high vs low load training did not make a difference for hypertrophy while higher load training was beneficial for maximum strength development.
In a 2021 SR including 14 studies of subjects with prior resistance training experience, the authors found the number of sets close to failure correlated with hypertrophy while the rep ranges and training frequency were less consequential (assuming the same total number of sets per week were done when training at different frequencies).(Baz-Valle, 2021) However, they did find overall more hypertrophy with rep ranges in the 6-20 range compared to <6 reps per set. A 2020 review on the topic of rep ranges found no correlation between the rep range and the observed outcome regarding strength, hypertrophy, and muscular endurance adaptations.(Fisher, 2020) An 2021 review draws similar conclusions, summarizing the findings of the literature in the following infographic(Schoenfeld, 2021b):
Thus, it seems a wide variety of rep ranges, likely anywhere between 6-30, can yield similar adaptations for hypertrophy, general strength, and potentially even muscular endurance, assuming sets are taken at least close to failure. Lower rep ranges below 6 are likely beneficial for building up one’s 1RM due to the more specific neurological adaptations that occur with heavier training loads.
Tip: This rep range of 6-30 allows a lot of leeway when designing a program. There are several considerations when choosing a desired rep range within this window:
- higher rep sets will take longer
- people with limited access to heavy equipment can perform higher rep sets close to failure with lighter resistance
- for people with injuries or medical conditions who would otherwise feel unsafe utilizing heavy loads, using lighter loads with higher reps is still effective
- with exercises where it is difficult to increase the load in small increments:
- you can use a given load until you are close to the 30 rep limit
- at this point add weight and move down to the 6-10 rep range
- continue to work with the same weight until you again progress close to the 30 rep limit
- individuals who prefer to stay in the lower or higher rep range can do so without hindering their progress
- alternatively, for people who want to mix things up you can include lower and higher rep ranges
Sets needed per muscle group per week for continued progress
When discussing sets with respect to overall training volume this does not include warm-up sets. Here we are only talking about “working” sets, which are the sets we perform to induce beneficial adaptations. If one does too few sets the training stimulus may be insufficient to induce change. If one does too many sets this may negatively impact recovery too significantly such that one does not recuperate sufficiently prior to their next training session.
What the research suggests
A 2020 SR/MA of studies evaluating men with a resistance training background found that doing a single set of 6-12 reps with 70-85% 1RM 2-3x/wk (“wk” = “week”) to failure with the squat and bench press elicits strength increases.(Androulakis-Korakakis, 2020) A 2017 SR/MA similarly found doing 1 set 3x/wk is effective but higher volumes (generally 2-3 sets 3x/wk) leads to greater strength progress.(Ralston, 2017) In a 2019 review describing an evidence-based approach to strength and hypertrophy training the authors note that >15 sets per muscle per week may be too much for hypertrophy and strength purposes, potentially due to impeding recovery.(Morton, 2019) However, one of the studies used to conclude this upper threshold has since been retracted.
As indicated above, in a 2021 SR including 14 studies of subjects with prior resistance training experience the authors found that the number of sets close to failure correlated with hypertrophy while the rep ranges and training frequency were less consequential.(Baz-Valle, 2021) In a 2017 SR/MA of 15 studies (only 2 included individuals with prior resistance training experience) ≥10 sets/muscle/wk yielded greater hypertrophy than fewer sets; however, using ≤4 sets/muscle/wk still induced significant progress.(Schoenfeld, 2017b)
It is clear that pushing close to failure with only 2-4 sets a week elicits progress. Performing ≥10 sets/muscle/wk induces greater progress. At this point there is no well-defined upper limit above which further sets seems to be counterproductive. This is due in part to varying protocols; an upper limit likely depends on training frequency, set proximity to failure, and other aspects of recovery such as sleep and nutrition.. However, there do seem to be diminishing returns for extra volume once one reaches >10-15 sets/muscle/wk. Thus, aiming for 10-15 set/muscle/wk should provide the majority of potential beneficial training adaptations for most trainees, though people can do less than this and still make progress.
Note: When performing a single-joint exercise such as a bicep curl it is clear this should count as 1 set for the biceps. When performing a multi-joint exercise, such as the chin-up, this is less clear. Should this count as 1 set for the latissimus dorsi (“lats”) and 1 set for the biceps, or should we assign a fraction of a set to each major muscle group? In general most practitioners count this as 1 full set for each main agonist (the biceps and lats in this example); this same logic applies to all of the main agonists in all of the various multi-joint exercises.(Schoenfeld, 2019b; Nunes, 2021)
Tip: For beginners who worry about developing consistency with resistance training, it is completely appropriate to begin with 2-4 sets/muscle/wk. This allows short workouts and consistent progress, albeit more slowly than with higher training volumes. During this time you should focus on building the necessary habits to fully incorporate resistance training into your lifestyle. Additionally, this is an excellent option to help minimize soreness.
At any point in time if progress begins to plateau you can consider increasing training volume by incorporating more sets. When you hit another plateau you can add additional sets. Eventually you will reach the 10-15 set/muscle/wk metric; at this point there are several methods you can use to make further progress when you reach a plateau. I will discuss some of these methods in Lesson 13.
Optimal tempo for each repetition
Tip: Whether to pause or not is largely based on personal preference. Some considerations:
- For people who have issues maintaining good form throughout a set, a brief pause can help decrease momentum and make it easier to ensure proper positioning throughout the movement.
- Along with the above consideration, by aiding good form pausing can decrease the risk of injury.
- For individuals pursuing athletic endeavors part of athletic training generally includes maximizing the stretch reflex. You can specifically develop this with exercises such as plyometrics. Traditional strength training is also effective if you do not pause between the eccentric and concentric phases and perform the concentric phase as rapidly as possible.
- As the stretch reflex primarily assists the beginning of the concentric phase, pausing specifically makes the beginning portion more difficult (though the latter portion can also be more difficult due to the beginning portion generating less momentum to carry the weight through the latter portion). Thus, specific exercises “feel” different when pausing or not pausing. For this reason you may find that it seems better to pause on some exercises than others.
Ultimately you can try incorporating pauses on various exercises and decide if you want to continue including them or not. For the purpose of improving form and helping decrease the risk of injury a brief pause (~0.5 seconds) is sufficient. This will eliminate any excess momentum or “jerking” that you may otherwise experience. To minimize the stretch reflex, pausing at least 1 second is beneficial.
Note: At one extreme of tempo we can simply pause for an indefinite period of time; if we keep tension on our muscles during this then we are performing an isometric contraction. I generally do not advise beginners or even intermediate-to-advanced lifters incorporate these over the more traditional methods of performing repetitions. Isometrics are more of an advanced technique with specific applications. That said, for completeness, a 2019 review summarized much of the literature regarding isometric contractions and came to the following conclusions(Lum, 2019):
- hypertrophy: perform isometric contractions at 70-75% of maximum voluntary contraction (“MVC”) for 3-30 seconds per repetition for a total of 80-150 seconds per session
- maximum strength: perform isometric contractions at 80-100% MVC for 1-5 seconds per repetition for a total of 30-90 seconds per session
- explosive strength: perform isometric contractions where you generate force as quickly as possible to near 100% MVC
The average individual will likely never need to incorporate prolonged isometric contractions.
What the research suggests
In a 2017 SR/MA including 15 studies, both faster and slower concentric phases yielded similar strength results; however, there was a trend towards better results with a faster concentric phase when working at 60-79% 1RM.(Davies, 2017) In a 2020 SR/MA of 54 studies, resistance training with a fast bar speed (at <60% 1RM loads) or with the concentric portion of the rep performed as fast as possible yielded greater improvements in rate of force development than intentionally slower bar speeds.(Blazevich, 2020)
Similarly, a 2019 review of studies with elderly participants also found that resistance training with the concentric portion of reps performed as fast as possible yielded the greatest benefits for force and power production.(Orssatto, 2019) This same author published a 2020 SR/MA evaluating power training compared to moderate-velocity training for hypertrophy in the elderly and found similar results with both methods.(Orssatto, 2020) A 2020 review found a slight benefit to faster lifting speeds for strength & power production; however, the authors found similar results otherwise and noted that purposefully doing reps slowly is a good strategy when working on technique for beginners.(Lyons, 2020)
Additionally, regarding hypertrophy, a 2018 SR of 6 studies found conflicting results.(Hackett, 2018) All 6 studies used untrained subjects, small sample sizes (135 total participants within all 6 studies), and a relatively low load (<60% 1RM). Additionally, the methodology in several of the studies was questionable since some groups did not experience any hypertrophy; this is unusual in studies including beginners. In 3 of the 5 studies involving the legs slower repetition speed was advantageous while both studies involving the biceps found an advantage to faster repetition speed.
Note: In the last review all of the studies used loads <60% of 1RM. This makes it easier to study the influence of repetition speed as we can lift lighter loads more quickly. For example:
- With 50% of our 1RM we can easily perform either 1 or 5 second eccentric and concentric phases.
- With 90% of our 1RM it is much more difficult to perform very slow reps as our muscles will fatigue too quickly. On the other hand, we also cannot perform very fast reps since it takes longer to generate the required force required; recall the force-velocity curve from Lesson 1.
Several studies in the other reviews listed above did use heavier loads and then compared a controlled concentric phase (ie, a 3 second concentric) with an as-fast-as-possible concentric phase, even if this was not that much faster than the controlled concentric phase.
In a 2021 review, the authors considered differences in tempo of the concentric and eccentric portions.(Wilk, 2021) Most of the examined studies were in beginners to resistance training. The authors recommend that for hypertrophy the tempo does not matter much for either portion of the rep. For strength gains the total time of each rep should be <5 seconds with a faster concentric than eccentric portion. They note it is unclear whether the set’s duration matters and we need more research on this subject.
A separate 2021 SR of 24 articles (14 in untrained and 10 in previously trained individuals) evaluated the impact of repetition tempo on strength, hypertrophy, and power outcomes, concluding(Moreno-Villanueva, 2021):
- an optimal tempo for strength may be 2-4/0/1/0 for untrained and trained individuals
- an optimal tempo for hypertrophy includes keeping the repetition duration at <8 seconds – the importance of the length of the eccentric vs concentric phase is unclear but the eccentric phase should likely be longer than the concentric phase
- an optimal tempo for power includes keeping the repetition at <4 seconds for beginners and <8 seconds for previously trained individuals with the concentric phase done as explosively as possible (potentially with light enough resistance such that the concentric phase is <2 seconds)
While the research is less conclusive for hypertrophy, regarding strength and power there is a benefit to performing the concentric portion of repetitions as quickly as possible. Strength and hypertrophy correlate to a degree, and thus it seems likely that performing the concentric phase as quickly as possible will benefit, or at least not hinder, hypertrophy adaptations. However, this only applies if we do not compromise good form to perform the reps more quickly.
Tip: When performing the concentric phase as quickly as possible it is still important to control the weight to decrease the risk of injury and ensure you maintain good form. For the eccentric phase there are some exercises where we can perform this very quickly; for example, people who perform many pushups generally descend in <1 second while maintaining good form. However, with most exercises aiming for a 1-2 second eccentric phase promotes safety while avoiding wasting excess energy.
On the other hand, when performing the concentric phase as quickly as possible we must maintain good form. For heavier loads where the weight is not moving very fast this is not a significant issue. However, with lighter loads this is potentially problematic; I advise you to never sacrifice good form simply to move the weight more quickly.
Lastly, when performing warm-up sets I recommend you to purposefully avoid moving the first several reps as quickly as possible. When the weight is too light this places more stress on the joints and defeats the purpose of warming up the muscles. However, performing the concentric phase as quickly as possible on the last warm-up set/reps is beneficial; this helps prepare the nervous system to fire as quickly as possible when the first working set begins.
Full vs partial range of motion
A lot of people use a partial range of motion (ROM) instead of a full range of motion due to the belief this keeps the weight on the muscle instead of the joints. However, in doing this the muscle fibers are not worked through their full potential range of motion. Separately, some people find themselves stronger in a specific range of motion of a lift and thus preferentially stay within this range. This is due to ego and/or a belief that more weight yields more results (ie, performing a quarter squat instead of a full squat).
What the research suggests
Regarding range of motion, a 2020 SR of 6 studies indicated the literature is sparse but a full ROM is generally beneficial relative to a partial ROM, though 1 study did find a benefit to partial ROM with the triceps.(Schoenfeld, 2020) A separate recent review found that partial ROM is helpful to specifically target a certain portion of a muscle, but a full ROM leads to more overall growth throughout a full muscle.(Newmire, 2020)
When doing exercises a full range of motion is generally preferable. For example:
- pull-ups: start pulling upward with arms at full extension rather than with them already bent
- squats: descend as low as possible with good form instead of stopping a quarter of the way down
This also allows definitive endpoints for the range of motion; if stopping part way through the range of motion it is difficult to ensure you are stopping at the same point every time.
Note: It is important to keep in mind that the full range of motion for an exercise only applies to the joint ranges of motion that allow good form to be maintained. For example, when doing a squat you can purposely rotate your pelvis posteriorly and rock backwards to lower your glutes closer to the floor. While this increases the overall distance of the bar path (if you are doing this with a barbell on your back), this is not good form and I recommend avoiding this.
On this same note, two different individuals with different anthropometry may have significantly different full ROM. For example, longer arms leads to a longer ROM with the bench press, while shallower hip sockets may lead to a deeper squat without posterior pelvic tilt.
Below I have included simple pictures to illustrate different levels of squat depth. I discuss exercise technique in more detail in Lessons 9-12.
Tip: Be weary of shortening ROM just to use more weight. This is a common pitfall that benefits one’s ego without benefiting physiologic adaptations.
If you are ever doubtful about the ROM you are using, or of your exercise form in general, take a video of yourself and watch this directly after you perform a rep or set. This is an excellent tool to get real time feedback and allows you to immediately make adjustments. A large part of learning how to engage in exercise productively depends on developing kinesthetic awareness of how your body moves through space. Video feedback is an extremely useful tool to develop this quality.
How close to failure one should train
Training to failure involves taking a set to the point where no further reps are possible. At this point there are zero “reps in reserve” (RIR). If we stop one rep shy of failure then RIR = 1. Many people intuitively feel you have to push your body to the limit to get it to respond well and thus routinely take sets to failure. However, it is important to remember that while training provides a stimulus for growth and physiologic adaptations, these beneficial changes occur after training while we are resting & recovering. Additionally, our body generally repairs any muscle protein breakdown that occurs during a training session prior to synthesizing new muscle tissue. Thus, training to failure too frequently may lead to undesirable levels of local damage and prolonged recovery time. If so, this will yield slower progress than if one were to avoid training to failure.
What the research suggests
A 2016 SR/MA of 8 studies comparing training to failure versus training close to failure overall found no significant difference between the two approaches for improving strength.(Davies, 2016) A 2018 overview of considerations with strength training presented evidence that training to failure is not necessary and is possibly detrimental due to increased overall fatigue.(Suchomel, 2018) In an 2021 SR/MA (updated from Davies, 2016) including 15 studies (6 with subjects with prior resistance training experience) the authors found similar results when training to failure or not training to failure for strength development.(Grgic, 2021) However, they did find that when groups did not train to failure they achieved better results than groups that did train to failure if volume was not matched. This is presumably due to the non-failure group incorporating more training volume. Of note, all of the studies in the prior SR/MA evaluated young adults.
Regarding hypertrophy, a 2019 overview of evidence-based approaches for strength and hypertrophy training concluded that training to the point of volitional fatigue (“volitional fatigue” is frequently used to mean “failure”) or close to it with lighter loads (<60% 1RM) yields similar results to heavier loads.(Morton, 2019) The authors also indicate one should likely not train to failure exclusively. A separate 2019 viewpoint specifically evaluating training to failure for hypertrophy summarized much of the evidence (primarily studies conducted in untrained individuals) and suggested(Schoenfeld, 2019a):
- training to failure is not beneficial when doing sets with a relatively high load (ie, 6-12 RM)
- training closer to failure (ie, RIR = 0-2) is theoretically more important when training with lighter loads (ie, 20-30 RM)
- however, there is not much research evaluating this latter point
The most recent SR/MA that was mentioned above included 7 studies evaluating hypertrophy (2 with subjects with prior resistance training experience) and found similar results for hypertrophy with or without training to failure.(Grgic, 2021) However, in the two studies with subjects with prior resistance training experience there were mildly significant results (p-value 0.039) favoring training to failure. Only one of these latter two studies equated training volume and the total participants between the two studies was n = 40.
Training to failure is not necessary and can be detrimental if done too frequently. It leads to increased local fatigue, which can hinder subsequent performance and prolong recovery.(Vieira, 2021) At the same time, one must push themself hard enough to actually force their body to undergo beneficial adaptations. When lifting with heavier loads (ie, a 10-15 RM or heavier), staying at an RIR of ≤4 while doing sets with at least 6 reps (as discussed above) will likely allow beneficial adaptations to take place. When training with loads lighter than this staying at an RIR = 1-2 is more appropriate for a comparable training effect. Training to failure occasionally may produce beneficial adaptations, but this may require additional recovery time prior to the next training session.
Tip: Downsides to training to failure include:
- the greater amount of fatigue this induces – this requires a lengthier recovery time prior to a subsequent training session
- a higher risk of injury as form breakdown is more likely and a greater strain is placed on the body when one reaches failure
- it is physically more uncomfortable when approaching failure (though some individuals will not find this detrimental)
Thus, for beginners, I recommend staying away from failure. This helps prevent form breakdown issues; it is crucial for beginners to focus on maintaining good form while they are developing the neural adaptations and motor patterns of the new movements they are performing. After you are comfortable with your form, lifting to failure is still not necessary, but if you want to do it I would start with isolation exercises (ie, a single-joint exercise such as a bicep curl) as this is less likely to cause form breakdown. People who perceive difficulty with recovery from training sessions, either due to excessive soreness, a physically demanding job, age-related or medical comorbidities that impact recovery, or some other reason, may find avoiding failure entirely to be the best option.
On the other hand, many people underestimate how hard they can push themselves. Someone may think they are stopping at an RIR = 3 but in reality they may be able to do 5 more reps, so they are actually at an RIR = 5. One study evaluating this in individuals with and without prior training experience found similar results regardless of prior training experience; most people were accurate within 1 rep at RIR = 0-3 for the leg press and RIR = 0-5 for the chest press, but not all were accurate.(Hackett, 2017) I discuss more of this literature in Lesson 6.
As some people are less adept at estimating RIR than others, for safer movements once you develop consistent good technique I advise you to push to actual failure simply to learn what this feels like. If you consciously think about how your body feels with each rep as you approach failure, you can use this “anchor” set to better understand what RIR = 0, 1, 2, etc actually feels like. After this understanding is acquired you can more confidently lift to a specific RIR with future sets. You can repeat this anchoring process occasionally to help ensure continued accuracy.
Effective rest periods between sets
Once we complete a set we need to rest for the phosphocreatine stores to replenish sufficiently to allow a subsequent set. As discussed in Lesson 2, it can take ~1 minute to replenish these 50% and ~5-7 minutes to replenish these close to 100%.(Kraemer, 2012) If we take a set to failure we will likely use almost all of our phosphocreatine stores and will need to recover for a longer period than if we stopped the set short of failure. Other physiologic changes that occur while we rest include recovery of our heart rate and our respiratory rate as well as removal of metabolites (ie, lactate) from muscle. With longer rest between sets we experience fuller recovery and can lift more weight or more reps in a subsequent set. However, this comes at a cost of a longer overall workout unless we employ a strategy such as supersets or circuit training.
What the research suggests
A 2018 SR looking at the impact of rest periods on strength adaptations included 23 studies (10 with individuals with prior resistance training experience) and found that(Grgic, 2018b):
- individuals with prior training experience need to rest at least 2 minutes to maximize strength gains
- individuals new to resistance training can obtain similar adaptations with shorter rest periods (even <1 minute)
The authors did find some variability; multi-joint exercises done with higher reps seem to require longer rest periods.
A 2017 SR looking at the impact of rest periods on hypertrophy adaptations included 6 studies (1 with individuals with prior resistance training experience) and found no significant difference when comparing <60 seconds to 80-240 seconds between sets.(Grgic, 2017)
Within rest periods themselves many different strategies to aid recovery and improve results have been studied, including interset stretching, warming, cooling, aerobic activity, among others. Collectively, there is little consistent research showing a significant benefit of any of these modalities and any impact they have is likely much smaller than the duration of the rest period itself.(Latella, 2019)
People new to resistance training can keep rest periods short (ie, ~1 minute), though there is no harm in resting longer if desired. For people with resistance training experience resting longer is more beneficial; aiming for ≥120 seconds of rest between sets likely allows more productive sets and thus better progress long term.
Tip: For people who are doing supersets or circuit training there does not seem to be any concern of resting too long between sets; this would only be a concern if one were to essentially “cool down”. For example, if an 8 exercise circuit is done 3 times and each circuit takes 10 minutes, you will essentially rest 10 minutes between sets. This is not too long if the quality of the second circuit is similar to the first. In fact, a 2021 SR/MA found that circuit training can yield very good outcomes for body composition and strength gains.(Ramos-Campo, 2021) However, if you perform a set, take a 10 minute phone call, and then attempt a second set and the quality suffers due to needing to warm up again this is suboptimal.
As you become more advanced longer rest periods become more useful to ensure the quality of each set remains high. More advanced lifters may find themselves needing to rest 4-5 minutes between sets or potentially even longer depending on how fatiguing the individual sets are. For beginners this is generally not required.
When trying to determine an optimal rest time you can consider your heart rate and respiratory rate. If you feel out of breath and your heart rate is really fast after a set, waiting for this to come down to a degree and for breathing to normalize is one method to help determine you are ready for the next set. This does not apply to supersets or circuits training as different muscle groups are used in successive sets. While resting exactly 60 or 90 seconds between sets may work at times, incorporating considerations of your heart rate and respiratory rate as a form of auto-regulation helps ensure adequate recovery when different sets induce different degrees of fatigue.
Training frequency throughout the week
Training frequency typically refers to how many times a muscle group is trained throughout the week. If we train legs on Tuesday, chest/shoulders/triceps on Thursday, and back/biceps on Saturday, this is considered a training frequency of once per week for each muscle group even though there are 3 workouts during the week. Training more frequently allows more opportunities to impart a stimulus for further growth and adaptations while also working on technique. On the other hand, training too frequently may make it difficult to recover adequately between sessions if the total volume and intensity in any specific session is too high. Thus, one must strike a balance between training frequency and total workload per session.
What the research suggests
In a 2018 SR/MA evaluating the impact of training frequency on strength adaptations, 22 studies were included (3 of which had subjects with prior resistance training experience).(Grgic, 2018a) Overall, no impact of training frequency was seen. However, when splitting up studies between elderly and non-elderly subjects the elderly found similar benefits with 1 or ≥2 training days weekly. Younger individuals had greater adaptations when training ≥2 days weekly compared to 1 day weekly. Of note, in studies where weekly sets were matched training more days each week was not beneficial.
In a 2019 review of 28 studies examining the impact of frequency on hypertrophy there seemed to be a potential slight benefit to training ≥2 times weekly; however, overall results were similar when training a muscle group between 1-4 times weekly if total weekly sets were equal.(Grgic, 2019)
In a 2021 meta-regression of 15 studies examining the impact of training frequency on strength and hypertrophy in individuals ≥60 years old there did seem to be a small advantage to training 2 days weekly compared to 1 for strength adaptations without a significant influence on hypertrophy adaptations.(Kneffel, 2021)
A 2021 SR/MA evaluated the impact of training frequency on strength in individuals with prior training experience, included10 studies, and found no significant influence of training frequency when training volume was equated.(Cuthbert, 2021) The authors acknowledge most of the studies were not well-designed to increase maximal strength and the typical study duration of 6-12 weeks may not have been long enough for differences to become evident.
Overall there seems to be a benefit when training ≥2 days weekly compared to training 1 day weekly as this allows greater weekly volume, though substantial progress is possible when only training 1 day a week. Additionally, increased training frequency allows increased opportunities to practice the more complex movements. The benefit of training more frequently seems related to total weekly volume; when training more frequently we can perform more productive sets per week and thus accumulate higher total training volume. As indicated above, 10-15 sets per muscle per week is a great starting point for most individuals; you can split this up into 5-8 sets per muscle group when working each muscle group twice per week. For people with a more significant time crunch, training each muscle group twice weekly with 2-3 sets per session or training once weekly with up to 10 sets per session can still yield significant progress.
Tip: For people who want to train muscle groups more frequently there is no indication that training 4x a week is detrimental, and while there is not much research evaluating ≥5 days per week there is no conceptual reason to think this is counterproductive with a well-designed program. A benefit of training each muscle group more frequently is that individual sessions can include fewer sets, making workouts faster. Many people advocate resting a full day between training sessions for the same muscle group; this would make training ≥4 days weekly impossible. However, this is not a hard rule that you must follow. It simply becomes more important to appropriately manage training volume and monitor fatigue to ensure training on consecutive days is not detrimental.
On that note, there are two primary considerations:
- Does training a muscle group lead to some sort of systemic fatigue that affects non-trained muscle groups? If so training several muscle groups frequently throughout the week may contribute to excess fatigue.. A 2021 SR/MA indicates this is not a concern for muscular strength or power while this may be a concern specifically for muscular endurance, though it’s unclear if this latter effect is due to an impact on the muscles themselves or the fact that it can be difficult/uncomfortable to train for muscular endurance repeatedly with little rest.(Behm, 2021)
- Does training different body parts frequently lead to excess strain on one’s joints and other connective tissue? For example, depending one’s form various exercises such as dips, pull-ups, and squats can all be hard on the elbows. Perhaps the muscles can handle frequent training but the joints will not be able to without suffering inflammation, leading to pain.
Thus, one can train very frequently if desired, but it is important to consider all aspect of one’s program to ensure the overall stress does not lead to difficulty with recovery.
I have compiled the above recommendations into the infographic below. If you skimmed or skipped over the above and anything in the infographic seems surprising, please refer to the relevant section(s) above for further details.
Note: For individuals short on time who want to workout effectively as quickly as possible, knowing this may not yield optimal progress but will still yield steady progress, click here for a nice review discussing this topic.(Iversen, 2021) I have included their summary table below. I discuss some of the time-saving strategies in Lesson 13 and considerations regarding a warm-up in Lesson 15. A quick workout can be done once weekly to good effect for beginners. Remember, track your progress over time and as long as you are improving then what you are doing is working. I discuss considerations for changing a workout program when progress stalls in Lesson 13.
We’ve now looked through what the research suggests when considering how to create a resistance training program. Clearly there are several variables that are not set in stone, rather there are multiple options that can be considered. Additionally, while the reviews above compile results from many studies, they do not necessarily capture the individual variability inherent within studies. Different people may develop better results with different program designs. Thus, the above should be considered to help develop a starting point, but once progress begins to slow down varying things in some capacity is worthwhile to see if your own body responds better to different parameters.
So with the above information we can create an effective resistance training program, and with linear progression this can prove useful for an extended period of time. However, eventually linear progression comes to an end and it can become more helpful to employ an autoregulation strategy. This can be done with or without a periodization approach, which allows for greater variety in one’s program as well as training multiple fitness attributes simultaneously or sequentially. We will discuss these topics in the next lesson.
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