Study Reviewed: Effect of Different Training Frequencies on Maximal Strength Performance and Muscle Hypertrophy in Trained Individuals – A Within-Subject Design. Neves et al. (2022)

Key Points

1. Researchers split 24 trained men into two groups of 12. All subjects trained the unilateral leg press three times per week on one leg and once per week on the other. In one group, volume load was equated between training frequencies in one group. In the other group, subjects performed more volume in the higher frequency condition.
2. Leg press 1RM and quadriceps cross-sectional area significantly increased from pre- to post-study in all four conditions. Further, even when comparing conditions within the non-volume-equated group, there were no significant differences between groups and only trivial effect sizes (strength: d = 0.17, +5.2%; cross-sectional area: d = 0.14, +2.6%) favoring higher frequency training.
3. Higher frequency training did not lead to significantly greater strength and muscle growth, even when more volume was performed. However, since increasing frequency is likely to increase training volume, lifters should be cautious about when and how much to add frequency, if taking this approach.

Over the years, we’ve postulated in MASS that increasing training frequency primarily serves as a vehicle to add more volume. The literature supports this, as meta-analyses have reported that higher frequencies only lead to significantly greater hypertrophy (2, 3) and strength gains (4) than lower frequencies when the higher frequency is coupled with greater training volume. Although the most recent meta-analysis on the topic (3) found significantly greater muscle growth when higher frequencies led to more volume, that comparison barely reached significance (p = 0.04). Nonetheless, one factor holding back the training frequency literature is that almost all research on the topic has made between-subjects comparisons. In other words, one group of individuals performed a high frequency protocol while another group completed a low frequency protocol. Then, researchers compared the mean changes between groups. While this is a common and acceptable design, it does not allow the researchers to evaluate each participant’s response to each protocol. A within-subjects design, in which each limb performs a different protocol, can assess how individuals respond to higher and lower frequency training, independent of what happens at the group level.

The reviewed study from Neves et al (1) was a within-subjects nine-week study in 24 trained men. The researchers split the men into volume-equated and non-volume-equated training groups. In both groups, one leg trained the unilateral leg press three times per week, and the other leg trained the unilateral leg press once per week. The only difference between groups was that one group trained each limb with volume load equated between the once and three times week frequencies, and the other group performed more volume in the three times per week frequency. Leg press 1RM and rectus femoris cross-sectional were tested before and after the study. The researchers compared the changes between conditions (one versus three times per week) within each group. Subjects in all conditions significantly increased leg press 1RM and cross-sectional area from pre- to post-study, but there were no significant differences between conditions within either group. Between-condition effect sizes were trivial within both the volume-equated and non-volume-equated groups (strength: d = 0.17; cross-sectional area: d = 0.14). However, subjects did gain 5.2% more strength and 2.6% more muscle in the higher frequency condition within the non-volume-equated group. These findings suggest that greater training frequency does not unequivocally lead to greater hypertrophy and strength gains when volume is equated. Further, when greater frequency is coupled with higher volume, strength gains and hypertrophy only lean slightly in the direction of higher frequencies. Therefore, if lifters are using frequency as a vehicle to add volume, they should be cautious about when and how much frequency to add to manage volume progressions and fatigue. This article will aim to:

1. Discuss the benefits of a within-subjects study design.
2. Review the present findings.
3. Compare the present findings to previous frequency research.
4. Discuss frequency as a vehicle to increase volume.
5. Provide examples of how to appropriately increase training frequency.

Purpose and Hypotheses

Purpose

The purpose of the reviewed study was to make within-subjects comparisons for changes in leg press 1RM and quadriceps cross-sectional area between high (3 days per week) and low (1 day per week) frequency training. The researchers made comparisons within a group that had volume load equated between training frequencies and within another group that performed more volume during higher frequency training.

Hypotheses  

The researchers hypothesized that higher frequency training would increase muscle growth and strength in both the volume-equated and non-volume-equated groups. 

Subjects and Methods

Subjects

24 men who could squat at least 1.5 times their body mass completed the study. Additional subject characteristics can be seen in Table 1.  

Study Protocol

The presently reviewed study was a longitudinal within-subjects design. The researchers split 24 trained men into volume-equated and non-volume-equated groups. Both groups trained the unilateral leg press three times per week on non-consecutive days with one leg, while the other leg performed the leg press only once per week. In the volume-equated group, subjects performed the same volume load (sets × reps × weight lifted) on both legs; however, in the non-volume-equated condition, subjects performed more volume load with higher frequency training. The researchers assessed leg press 1RM and rectus femoris cross-sectional area before and after the study. 

Non-Volume-Equated Group

In the non-volume-equated group, subjects performed 12RM sets in weeks 1-3, 10RM sets in weeks 4-6, and 8RM sets in weeks 7-8 on both legs. The leg assigned to the once-per-week frequency performed nine sets in the single training session. The leg assigned to train three times per week performed three sets in each session (nine total sets per week). Subjects completed all sets to failure on both legs. Thus, the three-time-per-week frequency limb could potentially achieve a higher total training volume load by maintaining a higher load over their sets since that leg should be fresher from set to set due to fewer sets per session.

Volume-Equated Group

Subjects always performed training on the once-per-week limb first and performed nine sets during their weekly training session using the same loading scheme as the non-volume-equated group. After subjects completed the nine sets with the once-per-week limb, the researchers calculated the average load lifted across all sets, and the volume load, to determine how to equate volume on the other limb. For example, if a lifter performed 99 reps over nine sets (11 reps per set) using an average load of 120kg, then the volume load would be 11,880kg. In this case, subjects would be assigned to perform nine total sets for the week (three sets each session) in the three times a week frequency limb with 120kg for the same number of repetitions. The training protocols for both groups can be seen in Table 2. 

Findings

Volume Load

As expected, volume load was not significantly different (p = 0.999) between training frequency conditions within the volume-equated group (1x/wk: 167,582 ± 13,673kg; 3x/wk: 167,586 ± 13,661). Also, as expected, within the non-volume-equated group, subjects performed a significantly greater volume load (p < 0.001) on the limb training three times per week (164,894 ± 12,885kg) than on the limb training once per week (137,986 ± 8,126kg). 

Strength and Cross-Sectional Area

Subjects significantly increased leg press 1RM and cross-sectional area in all four training conditions (p < 0.001), but there were no statistically significant differences (p > 0.05) in the magnitude of change between conditions. Between-condition (between frequencies) effect sizes were trivial within the volume-equated group (strength: d = 0.15 and cross-sectional area d = 0.02) and the non-volume equated group (strength: d = 0.17 and cross-sectional area: d = 0.14). However, within the non-volume-equated group, subjects did gain 5.2% more strength and 2.6% more cross-sectional area in the three times per week condition than in the once per week condition. All findings can be seen in Table 3, the individual response for strength and cross-sectional area in the volume-equated group is in Figure 2AB, and the individual responses for the non-volume-equated group are in Figure 3AB. 

Criticisms and Statistical Musings

If you read the full text from Neves et al (1), you’ll notice different between-condition effect sizes for both strength gains and cross-sectional area changes in the non-volume-equated group than reported in this article. Specifically, the authors reported moderate effect sizes of 0.51 for strength and 0.63 for cross-sectional area in favor of the three times per week frequency condition within the non-volume-equated group. That is quite the difference from the trivial effect sizes of 0.17 (strength) and 0.14 (cross-sectional area) reported in the Findings section of this article.

The discrepancy is because Neves and colleagues reported their effect sizes as Cohen’s dz scores. A dz score is calculated as [(mean of 3x/wk frequency change score – mean of 1x/wk frequency change score) / pooled standard deviation of the change scores]. In this article, I calculated the effect sizes as a d-value (not a dz) with the equation: [(mean of 3x/wk frequency change score – mean of 1x/wk frequency change score) / pooled standard deviation of the baseline values]. You’ll notice that the difference in these equations is the divisor (baseline standard deviation versus change score standard deviation). If the divisor is larger, then the quotient will be smaller. The baseline (pre-test) standard deviation is almost always larger than the standard deviation of the change score, so using the change score standard deviation will typically inflate the effect size. In this study, the inflated effect size suggests a moderate difference in strength gains and muscle growth between conditions when, in fact, the effect was trivial.

To fully understand the importance of the distinction between a d-value and a dz score, it’s crucial to understand what an effect size is supposed to tell you. An effect size should convey how many standard deviations a group changed or, in the present context, how many more standard deviations strength and cross-sectional area changed in one condition than the other. To determine how many standard deviations a group changed, or one group or condition changed more than the other, an effect size must be calculated using the baseline variability of the characteristic (in this case, strength and cross-sectional area) within the population. The metric of the variability of strength and cross-sectional area is indeed the pre-test standard deviation. However, calculating a dz score with the change score standard deviation rescales the calculation based on the consistency of change scores rather than the baseline variability of the measurement. Therefore, a dz score primarily conveys information about the variability or consistency of the change, not the magnitude of the change. 

This distinction is important because a reader seeing effect sizes of 0.51 (strength) and 0.63 (cross-sectional area) may conclude they are likely to increase strength and muscle growth by over half a standard deviation more by training three times per week compared to once per week if using more volume. However, that conclusion would be misleading, because the dz effect size metric primarily pertains to the consistency of the effect. Therefore, if reading an original study on your own, I would encourage you to recalculate the listed effect sizes before you place too much confidence in them. If your calculations are off by a couple hundredths or so, that’s likely a rounding error (no big deal). However, if your calculations are off by much more (as they were in this article), it’s possible that the authors reported dz scores. Ideally, the researchers would have explained this in the statistical analysis section of their paper and interpreted their effect sizes accordingly. 

To make your calculations simple, use this link. Once you enter the necessary values, the calculator will spit out three different effect sizes. The values of interest are usually Cohen’s d and Hedges’ g. The only difference between those two values is that Hedges’ g considers sample size when making between-group or between-condition comparisons. Therefore, if you make a between-group comparison and one group has 15 subjects, and the other has 12, then be sure to enter those values in the sample size cells and use the computed g value.

Interpretation

The presently reviewed study from Neves et al (1) found that increases in leg press 1RM and cross-sectional area were not significantly different between training three times or one time per week in both volume-equated and non-volume-equated comparisons. Training frequency has been well-researched over the past decade, so this article is an opportunity to dive into it. Therefore, this interpretation will review the present findings, compare these findings to the existing literature, discuss the interaction between frequency and other variables (volume and load), and provide examples of how to increase training frequency. However, the most important aspect of this study is that it made within-subjects comparisons, which is rare in the frequency literature. 

The typical comparison in the frequency literature is between-subjects. This comparison means that subjects are split into higher (e.g., three days per week) and lower frequency (e.g., one day per week) training groups. Researchers then compare the magnitude of change in strength and muscle size. Although that type of study design is the overwhelmingly predominant method, it is also limiting. As MASS has discussed, there are large interindividual responses to training protocols. For example, the percentage increase in leg extension strength ranges from 0 – 250% in untrained women and 0 – 150% in untrained men over 12 weeks of training (5). Additionally, even in trained individuals, researchers have reported a wide range of changes in quadriceps muscle thickness (-9.1% to +48.1%) following 12 weeks of training (6). Consequently, if a research study reports a statistically significant difference in outcome measures between groups, some individuals in the “statistically superior” group may not have gained any strength or size. Knowing that training response is individual, this lack of response by some within the “superior” group begs the question, “would the individual have responded better in the other group?”

In fact, our previous video, “Evidence for Individualization in Training Theory,” illustrates the concept of comparing individuals to themselves. This video discussed two key studies, Peltonen et al. (7) and Angleri et al. (8), demonstrating that individuals responded differently to specific protocols. Peltonen et al. (7 – MASS Review) conducted a 20-week crossover design study in which trained men performed strength-focused training for 10 weeks, followed by power-focused training for the next 10 weeks. Peltonen and colleagues reported that for changes in leg extension rate of force development, six individuals were “maximum strength responders,” four were “power responders,” and four were “non-responders.” Specifically, the maximum strength responders improved their rate of force development by 100% in the strength-focused block but by only 3% in the power-focused block. On the other hand, the power responders increased their rate of force development by 53% in the power block, but only 11% in the strength block. If Peltonen and colleagues had concluded this study after only the strength block, then eight subjects (the 4 non-responders and 4 power responders) would have been classified as non-responders. Thus, as a crossover design study, the subjects served as their own control in Peltonen et al, and researchers made within-subjects comparisons to test how an individual responded to both protocols.

Angleri et al. (8) conducted a 24-week within-subjects design study in which 16 men performed the unilateral leg press and leg extension, with one leg doing so in a drop set fashion and the other leg using traditional sets. Another 15 men performed the exercises with one leg using pyramid style sets and the other leg using traditional sets. There were no significant differences between conditions (drop set vs. traditional; pyramid vs. traditional). However, for the drop set vs. traditional comparison, five subjects increased leg press strength more with traditional training, two subjects responded better with drop set training, and nine responded similarly to both training styles. That means that ~44% of subjects (7 out of 16) responded better to one training style than another in the drop set versus traditional comparison. 

Further compounding the issue with between-group study designs is that many studies in applied exercise science are underpowered. For instance, suppose researchers report no significant difference between groups for strength gains in a longitudinal parallel-groups design study that has only eight subjects in each group. In that case, it’s possible some subjects in each group would have responded better to the other training protocol. Therefore, if practitioners adopt the conclusion from this theoretical study that “it doesn’t matter which protocol you use,” then that could limit the progress for some. For example, my other written review from this month reviewed a parallel-groups design study (9). In that study, one group achieved progressive overload via load and the other via reps. The range of increases for strength was +5.8 – 55.7% in the load group, and +4.0 – 33.2% in the reps group, and the authors concluded there were no clear differences for strength gains between groups. However, it’s possible that the individuals who had smaller increases with one load progression strategy could have benefited more from the other strategy and vice versa. An appropriate follow-up to that study would be a within-subjects design in which subjects performed the unilateral leg press with load progressing on one limb and reps progressing on the other. That design would allow for a within-subjects comparison and could determine if individuals responded differently to each progression scheme.

An example of a between-subjects comparison from the training frequency literature comes from Colquhoun et al (10) in 2018. Colquhoun and colleagues compared a group of trained men using a frequency of six times per week on the squat and bench press and twice per week on the deadlift to a group training the squat and bench three times per week and the deadlift once per week. Both groups performed similar volume load and set volume on each exercise. There were no significant differences between groups for changes in squat (3x/wk: +12.2%; 6x/wk: +12.0%), bench press (3x/wk: +7.7%; 6x/wk: +8.6%), or deadlift 1RM (3x/wk: +11.8%; 6x/wk: +12.6%). However, three subjects in the three-times-per-week group increased their powerlifting total (sum of squat, bench, and deadlift 1RMs) by < 5%, as did two subjects in the six-times-per-week group (one actually lost strength). Further, two subjects in each group improved their powerlifting totals by > 20%. Thus, this illustrates the case made earlier that it cannot be known from the Colquhoun et al study how the low or high responders would have responded to the other protocol. 

Despite the discussion about within- versus between-subjects comparisons, the Colquhoun et al study’s (10) findings and the presently reviewed study’s findings (1) are in pretty good agreement with the total body of literature. Two meta-analyses from Schoenfeld et al, one in 2016 (2) and the other in 2019 (3) tackled training frequency and hypertrophy, while a meta-analysis from Grgic et al 2018 (4) examined frequency and strength gains. The more recent Schoenfeld meta-analysis concluded that greater training frequency did not lead to greater hypertrophy when volume was equated. Further, Schoenfeld found that, although muscle growth was significantly greater when pooling twice and three times per week and comparing it to one session per week, this comparison barely reached the significance threshold (p = 0.04). Further, Schoenfeld and colleagues noted that this difference between higher and lower frequencies was only “modest.” In fact, for non-volume-equated studies they reported average muscle growth of 3.4% with three times per week training and 1.9% with twice per week training. That’s only a 1.5% difference between training frequencies, which is not too far off the 2.6% greater muscle growth in favor of higher frequency training, in the presently reviewed study within the non-volume equated group. One important distinction between the Schoenfeld metas and Neves et al is that the Schoenfeld meta included studies which were equated for volume by equating sets × reps, while Neves et al equated volume load (sets × reps × weight lifted). Nonetheless, the findings seem to be mostly similar.

The strength meta-analysis from Grgic et al (3) also found that greater training frequency on a muscle group tended to lead to greater strength gains, but only when studies did not equate volume between higher and lower frequency groups. In other words, strength increases favored higher frequency when subjects in the higher frequency group performed more volume. Further, Grgic et al reported that the magnitude of the effect tended to be frequency-dependent up to four days per week, when higher frequency was coupled with more volume. So, the Colquhoun study (10), which equated for volume, did not observe differences in strength gains between training frequencies, and neither did the volume-equated within-subjects comparison in the presently reviewed study. However, even though the comparison was not statistically significant, subjects did gain 5.2% more strength, on average, with higher frequency in the presently reviewed study within the non-volume-equated group. Further, in a subgroup analysis Grgic et al (3) found that young adults (p = 0.024), but not old adults (p = 0.093) experienced a significant benefit of greater frequency training when performing more volume, possibly due to impaired recovery ability in older adults. Therefore, when considering there is some evidence to suggest an effect for frequency on strength when more volume is performed, but no effect when volume is equated between frequencies, this suggests to me that you should let frequency do its thing to reap the benefits.

What does it mean to let frequency do its thing? It means, as everyone’s second favorite member of the MASS video department, Eric Helms, once said to me, “frequency is a vehicle to increase volume.” In other words, if a lifter is performing squats for 3 × 8 at 100kg twice per week (6 weekly sets and 48 weekly reps) and instead splits up those six sets into three sessions of 2 × 8 at 100kg, that’s not letting the frequency do its job. In this context, the “job” of additional frequency is to add more volume, or to allow for more quality sets by spreading out volume if too many sets are performed in one session. However, in the example above, performing three sets twice per week, especially if the sets are shy of failure, is hardly enough to necessitate splitting up the three sets over more than one session. 

The presently reviewed study (1) does present an instance where splitting the same number of sets over more sessions makes sense. Specifically, subjects performed many sets (nine) of leg press in a single session with once-per-week training in the non-volume-equated group; thus, splitting up the sets into multiple sessions made sense. Additionally, all sets were performed to failure, which means that set-to-set fatigue was likely high. Therefore, by splitting sets up into three per session, subjects were fresher from set-to-set than when nine sets were performed per session and maintained a greater load lifted which increased volume load. Importantly, as I wrote about extensively, hypertrophy occurs independently of the load lifted; thus, it would have been nice to see the higher frequency condition within the non-volume-equated group perform more sets. That scenario would be more likely to reveal a benefit of higher frequency for hypertrophy. Moreover, since load was the component driving volume, this is possibly why strength benefits (+5.2%) with greater frequency outpaced hypertrophy benefits (+2.6%). However, it is, of course, questionable if greater frequency had any beneficial effect at all in this study. 

One other note on the presently reviewed study is that the individual responses for the non-volume-equated group (Figure 2AB) reveal that subjects either had similar responses between conditions or increased strength and cross-sectional area markedly more in the three times per week condition. In fact, only one subject (Figure 2A) seemed to have markedly worse strength gains on the three time per week frequency leg. This may be the case because of how the researchers achieved the volume difference in this study. As noted earlier, since the number of sets and the repetition target was the same between conditions, subjects achieved more volume with three times per week training by using a greater load. Lifting a heavier load was achieved by subjects feeling more recovered from set-to-set when performing three sets per session (3x/wk. condition) as opposed to packing nine sets into one session. However, since not everyone fatigues at the same rate, some may have maintained load (or have a minimal decline) over the nine sets with once per week training. In that case, those individuals may have wound up performing a similar volume load in both conditions, negating the frequency benefits. To address this, the researchers could have calculated the differences in individual volume load between conditions and the individual differences in both muscle growth and strength gains between conditions. Then, the researchers could have conducted a correlation between this difference in volume load with the difference in muscle growth and the difference in strength. The researchers also could have isolated just load and conducted those correlations with only the difference in load between conditions instead of volume load. 

The only other within-subjects frequency study is from Damas et al. (11). That study did not show a significant difference in strength gains or hypertrophy in untrained men performing the unilateral leg press five times per week versus two or three times per week, despite the men performing more volume with five sessions per week. However, the researchers did observe a highly individual response. Specifically, 31.6% and 26.3% of subjects experienced greater muscle growth and strength gains, respectively, with five days per week of leg extension training than with the other frequencies. Additionally, 36.8% and 15.8% of subjects experienced greater muscle growth and strength increases with the lower frequencies compared to training five days per week. The Damas study highlights that not all individuals require the same volume to progress. Further, the point of diminishing returns of volume for hypertrophy and strength may be much lower for some than for others. Moreover, the Damas study emphasizes that lifters and coaches shouldn’t take the present study’s results and conclude that “greater frequency leading to more volume is the better approach for everyone.” That statement may be true for some, but, as Damas and colleagues observed, a lower volume may be more beneficial for others. To be clear, there’s nothing wrong with applying the mean findings from a study. If a study shows a significant difference between groups or conditions, the protocol that researchers found to be superior will probably be a net positive for the majority. But the question is: how do lifters and coaches know if they will respond better to one protocol or another? I have some thoughts and opinions on this question, but they are unsubstantiated and will have to wait for another day. Ultimately, the answer to this question is one of the great resistance training mysteries of our time. 

As I said above, mean data doesn’t apply to everyone. Yet, I also noted that there’s nothing wrong with discussing how to implement findings that apply to the majority, because it is helpful to provide general training recommendations. Therefore, if someone is looking to add volume, adding frequency is a vehicle to do that. For example, if someone is currently progressing on two sets of squats per week, they can likely add a third or even a fourth set without increasing frequency. However, set quality will begin to decline at a certain point; thus, if aiming to complete six squat sets per week, it makes sense to split the sets into two days per week. However, it doesn’t make sense to triple your volume and frequency from three sets in one day to nine sets over three days. Similarly, doubling training volume from eight sets of squats over two days to 16 sets over four sessions is not advisable. The main point is that frequency and volume should progress gradually under most circumstances.

As usual with programming, it is important to consider the downstream effects of adjusting training variables such as frequency and volume. For example, if squats are increased from two to three days per week, should assistance work volume increase as well? Of course, it could, but I probably wouldn’t change it too much until you adapt to the new squat volume. Further, I would spread out the assistance work over the three squat days, and make sure to position the exercises that result in the most fatigue (i.e., long ROM movements such as RDLs) farther away from the heaviest squat day to minimize the chance of sore hamstrings during heavy training. I’d also advise staying shy of failure, at least early in the week, when training with higher frequencies, since training to failure tends to exacerbate fatigue compared to non-failure training (12 – MASS Review). An example of increasing training frequency for certain muscle groups (legs, back, and biceps) while accounting for other factors, such as proximity to failure and positioning of specific exercises within the week, can be seen in Tables 4 and 5.

To illustrate what I was trying to accomplish with Tables 4 and 5, let’s focus on the squat and deadlift prescriptions. In Table 4, the back squat was performed for 10 sets over two sessions and progressed to 12 sets over three sessions (four sets per session) in Table 5. Further, the proximity to failure in Table 5 is of a greater RIR (farther from failure) to manage fatigue, since there are more total sessions that leave less time for recovery. As a consequence of the increased per-set RIR, the projected load lifted has decreased on the 8-rep and 6-rep days compared to Table 4. However, spreading training over three sessions allows for day three (i.e., Friday) to be of lower reps and higher relative intensity (percentage of 1RM); thus, the peak load lifted is higher in Table 5 than in Table 4. Further, the squat on Friday is closer to failure since there is more recovery between Friday and Monday (72 hours) than between any other squat training days.

The deadlift is prescribed once per week in Table 4, but twice per week in Table 5. With the additional volume in Table 5, the deadlift is now trained farther from failure earlier in the week to ensure appropriate recovery for the other squat and deadlift sessions. Another important note is that RDLs were on Monday for four sets to a 1-3 RIR in Table 4, which was feasible because there were 72 hours until the next training day. However, with only 48 hours between training days in Table 5, I moved RDLs to after the heavy squats on Friday. All of the “downstream” changes aim to disseminate volume appropriately to manage fatigue from session to session to accommodate the additional frequency and volume. Therefore, if a coach or lifter is aiming to increase frequency as a vehicle to increase volume, be sure to be mindful of these downstream effects and to make nuanced changes. Lastly, there are other changes to the assistance work between the tables. These changes include spreading the volume over more sessions and training farther from failure.

Additional Thoughts

I have three additional thoughts. First, continuing on the frequency-volume relationship, a lifter may add frequency when cycling through periods of really high volume or overreaching. However, I wish to stress the “cycling” aspect of this, as there are times when high frequency is appropriate and times when it is not. In other words, very high-volume high-frequency programs should not be prescribed long term. This video shows how to progress to a frequency of five times per week, while this video demonstrates how to cycle back to a lower frequency.

Secondly, although frequency can be a vehicle for higher volume, it can also be a vehicle to increase other aspects of programming. For example, if someone interested in maximal strength is aiming for more high-quality heavy singles each week, adding frequency, but minimizing volume, may be advisable. Specifically, if a competitive powerlifter aims to perform three near max singles (e.g., single at 0-1 RIR) on the squat each week to peak 1RM strength, it is probably preferable to spread these out over three days rather than on one day. Further, if a lifter wished to perform daily 1RM training, then training with a high frequency (every day) would be required to accomplish this program. With any configuration of frequent 1RM (or near 1RM) training, keeping volume fairly low is advisable. Therefore, in contrast to this interpretation’s discussion of the frequency-volume relationship, increasing frequency for heavy training should not also come with a large volume increase.

Lastly, increasing frequency could also be used to achieve more practice on the main lifts. For example, if someone is new to training a skilled movement like the squat, bench press, deadlift, clean and jerk, or snatch, then they may add additional sessions to practice technique. Therefore, a lifter could perform one session per week to increase muscle growth and strength, but add a couple of additional days where they perform the lift with a lighter load to practice technique. Further, previous data (13 – MASS Review) has suggested that training with as little as 10% of 1RM could accelerate recovery on the same muscle group. Thus, performing “practice” squats might also be beneficial for recovery.

Next Steps

I’d like to see a within-subjects design study comparing a frequency of once per week, three times per week, and five times per week with exercises targeting a few different muscle groups. In this study, I would scale the set volume with frequency. However, I would also have the subjects train close to failure (0-1 RIR) in the once per week condition, with moderate proximity to failure in the three times per week condition (2-3 RIR), and far from failure (4-6 RIR) in the five times per week condition. This design would allow frequency to “do its thing” and facilitate more volume. It would also allow subjects to train closer to failure in the lower frequency conditions, since managing recovery is less of an issue. Researchers could accomplish a within-subjects design by recruiting 30 people: 10 subjects could train one limb once per week and the other limb three times per week, 10 subjects could train one limb once per week and the other limb six times per week, and 10 subjects could train one limb three times per week and the other limb six times per week. 

Application and Takeaways

1. Neves et al (1) found, in a within-subjects design, that gains in 1RM leg press and rectus femoris cross-sectional area were not statistically different following nine weeks of training whether volume was equated or not between conditions. However, subjects did gain 5.2% and 2.6% more strength when training three times per week than once per week when completing greater volume load in the three times per week condition.
2. The totality of the literature suggests that higher training frequencies only enhance muscle growth and strength when frequency is used as a vehicle to increase volume, and the benefit for muscle growth tends to be modest.
3. Overall, training with greater frequencies is an appropriate way to increase volume. However, each individual should consider if this approach is suitable. When aiming to add volume via increased frequency, be mindful not to increase either variable too much (or too quickly), and remember to make the other nuanced changes within a training week to manage fatigue and recovery. 

References

1. Neves RP, Vechin FC, Teixeira EL, da Silva DD, Ugrinowitsch C, Roschel H, Aihara AY, Tricoli V. Effect of different training frequencies on maximal strength performance and muscle hypertrophy in trained individuals—a within-subject design. Plos one. 2022 Oct 13;17(10):e0276154.
2. Schoenfeld BJ, Ogborn D, Krieger JW. Effects of resistance training frequency on measures of muscle hypertrophy: a systematic review and meta-analysis. Sports medicine. 2016 Nov;46(11):1689-97.
3. Schoenfeld BJ, Grgic J, Krieger J. How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of studies examining the effects of resistance training frequency. Journal of sports sciences. 2019 Jun 3;37(11):1286-95.
4. Grgic J, Schoenfeld BJ, Davies TB, Lazinica B, Krieger JW, Pedisic Z. Effect of resistance training frequency on gains in muscular strength: a systematic review and meta-analysis. Sports Medicine. 2018 May;48(5):1207-20.
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