RPE vs VBT?

The question everyone has been dying to know: RPE VS VBT

Autoregulating subjectively (via RPE) and objectively (via VBT) have been supported to be superior to PBT. However, how do they compare head-to-head? Join me as I dive into the first ever study to compare these two methods of autoregulation.

Key Points

1. This study was the first ever to compare RPE vs velocity-based load prescription on 1RM strength improvements in the squat and bench press
2. Velocity-based load prescription resulted in more than twice the improvements in squat and bench press 1RM compared to RPE-based load prescription
3. Although this is the only study comparing these two methods of autoregulation, there is strong evidence to suggest that integrating velocity with RPE may be the optimal method for individualized load prescription in order to elicit the greatest improvements in 1RM.

Introduction

Wow! This was my first impression of the results of this study. They truly are astounding. Despite its limitations, this study has evidence supporting that velocity-based training (VBT) elicited more than twice the one-repetition maximum (1RM) improvements on the squat and bench press in comparison to rating of perceived exertion (RPE)-based training over the course of a 6-week training block (1). Now, some of you may be thinking, “VBT is better than RPE!” Or, some of you may be thinking, “this is only one study. RPE is better than VBT!” I’ll start this blog post by explicitly stating that I personally think a conceptual framework integrating both VBT and RPE is the optimal model for an individualized and autoregulated model of resistance training programming. However, I must also state that optimal is unattainable. Why? We can always improve. There will always be more research, more discussion, more learning. If you ask me, this is incredibly cool. It means that as science improves, coaches and athletes can concomitantly improve. In science, we typically compare one concept to another concept. Why? As scientists, we must ensure that the dependent variables under investigation are solely due to manipulations in the independent variable and not due to extraneous variables. In simplest terms, researchers typically compare one concept to another concept and everything else is the same (or at least controlled as much as possible). In practice, this often leads some coaches and athletes into thinking that “A” is superior to “B”, or vice versa. However, in practice, this black-and-white thinking process that concepts from the scientific literature are mutually exclusive is particularly troublesome. Why? The scientific literature provides us as coaches and athletes with concepts. That’s it. Well, mostly it. Now that us coaches and athletes have these concepts from the literature, we must identify which components of the concepts are beneficial, we must integrate those beneficial concepts, and then apply those concepts into practice. This concept, that we must think conceptually (whoa… some inception going on here) is what I’d like you to keep in mind as you read this article, as well as future articles and watch the webinars. Okay, now back to the VBT vs RPE debate. To date, there have only been 4 longitudinal studies comparing autoregulation to fixed loading on strength adaptations: two studies on RPE vs percentage-based training (PBT; 2, 3), and two studies on VBT vs PBT (4, 5). One of the two studies on RPE vs PBT demonstrated significantly greater strength adaptations for the RPE group (3), while the other study demonstrated no difference between groups (2). Similarly, one of the two studies on VBT vs PBT demonstrated significantly greater strength adaptations for the VBT group (4), while the other study demonstrated no difference between groups as well (5). Surprisingly, the presently reviewed study is the first ever to compare these two methods of load autoregulation.

Methods

Purpose

The primary purpose of this study was to compare RPE- versus velocity-based load prescription on strength adaptations and performance metrics following 6 weeks of resistance training.

Hypothesis

No direct hypothesis was provided, and the authors seemed unbiased towards either method of load autoregulation.

Research Question

Which method of load autoregulation is more effective at eliciting strength and performances outcomes over the course of a 6-week training block: RPE or VBT?

Subjects

A total of 20 semi-professional rugby players from the United Kingdom with a minimum of 2 years of resistance training experience participated in this study (Table 1). A major advantage of the subjects used in this study is evident: all subjects were familiar with RIR-based RPE as this was the predominant load prescription method used by the team’s Strength and Conditioning Coach.

Table 1: Subject Characteristics

Experimental Design

This study spanned 12 weeks in length and was comprised of two 6-week training blocks: a maximal strength block followed by a strength speed block. In other words, one group performed VBT for the initial 6-week training block followed by RPE-based training for the latter 6-week training block, whereas the other group performed the opposite (Figure 1).

Figure 1: Experimental design

This study employed a randomized cross-over design; however, it was not a true randomized crossover design. Although randomized cross-over designs are advantageous, the manner conducted in this study exposes two primary limitations. First, there was no washout period between the two training blocks. Secondly, the two training blocks were not identical. These two points are important in order to mitigate second order effects and ensure that the effects observed are attributable to the condition under investigation and not due to previous exposure to a stimulus.

Figure 2. True Randomized Crossover Study Design

Figure 3. Longitudinal Study Design

Training Protocol

The RPE and velocity-based training protocols were identical; differing solely in their method of load autoregulation. Nonetheless, both groups were prescribed loads designed to correspond to the same percentage of 1RM. Specifically, the authors adopted a table for normative values based on previous research to establish the relationship between percentage of 1RM, RPE, and VBT (Table 2). A major limitation to this approach, is that it has been well-established that velocity must be individualized (6); however, in a team setting using universal load-velocity profiles is typically more feasible. The maximal strength block was comprised of 4 sessions per week with 3 exercises per session, whereas the strength speed block was comprised of 3 sessions per week with 4 exercises per sessions. Furthermore, on each exercise, the maximal strength block consisted of 8 sets of 3 reps at 85 – 90% of 1RM with 90 – 120 second rest intervals, whereas the strength speed block consisted of 6 sets of 4 reps at 70 – 80% of 1RM with 120 second rest intervals. The specific training protocol for the maximal strength and strength speed block are illustrated in Table 3 and Table 4, respectively.

Table 2. Intensity Prescriptions

Table 3. Block 1: Maximal Strength

Table 4. Block 2: Strength Speed

Throughout week 1 of each training block subjects self-selected the appropriate loads for the first set on each exercise that corresponded to the prescribed intensity. On subsequent sets, if the velocity or RPE corresponded to the prescribed intensity, no load adjustments were made. However, if the velocity of any two reps was outside the prescribed velocity range or if the recorded RPE was outside the prescribed RPE range, load was increased or decreased accordingly. Regardless of the number of reps that were outside the prescribed velocity range or how far off the recorded RPE was from the prescribed RPE, the load was adjusted 5 kg and 1 kg on barbell and dumbbell exercises, respectively. The load used for the initial set of each subsequent week’s training session was the load used for the final set of the prior week’s training session. A limitation of load prescription for the VBT group is that the PUSH band accelerometer was used; however, it has been demonstrated to have significantly lower validity (accuracy) and reliability (consistency) than the Speed4Lifts linear position transducer at monitoring barbell velocity.

Statistical Analysis

This study analyzed the data with magnitude-based inferences (MBI); a method of data analysis that has gained some popularity in exercise science studies in recent years. Without diving into excessive detail, minimal researchers are proponents of this statistical method, while most statisticians are not. In short, in exercise science studies comprised of small-to-moderate sample sizes, magnitude based-inferences substantially reduce type II error rates; however, they substantially inflate type I error rates. An illustration of type I and type II errors is illustrated in Figure 4.

Figure 4. Type I and Type II Errors

Results

Strength on the squat and bench press was assessed prior to the training protocol, after the initial 6-week maximal strength block, and after the latter 6-week strength speed block. The results are presented as the average strength change from each autoregulation method. The overall change in squat 1RM for the VBT group was 7.5%; thus, to provide an example, the VBT group may have increased squat 1RM by 6.5% during the first 6-week training block, and the VBT group may have increased squat 1RM by 8.5% during the latter 6-week training block. Of course, based on the presentation of the findings it is unfortunately impossible to determine the strength change after each particular 6-week training block. Preferably, I would have appreciated if the authors reported 1RM strength changes following the 6-week maximal strength block and the 6-week strength speed block alone to discern second order effects. However, let’s pull back the curtain and look at the specific results of this study (Figure 5). The 1RM strength improvements in the VBT group were significantly greater and more than twice as much as the RPE group in both the squat (p = 0.00001) and the bench press (p = 0.003). Squat 1RM improved 7.5 ± 1.5 and 3.5 ± 0.8% in the VBT group and RPE group, respectively. Bench press 1RM improved 7.7 ± 2.1 and 3.8 ± 0.9% in the VBT and RPE group, respectively. Moreover, the effect sizes were 1.37 and 0.98 in favor of the VBT group for the squat and bench press, respectively.

Figure 5

Discussion

In the first ever head-to-head comparison of VBT to RPE-based load prescription, it was unarguably clear that VBT was the champion. However, the real question is: why? Why did VBT come out on top? First, let’s solely focus on this study. Second, let’s compare it to the previous aforementioned studies on load prescription.

Why Does VBT Seem to Elicit Superior Gains to RPE?

The first aspect of this study that really stands out to me is my hypothesized difference in RPE or repetitions in reserve (RIR). To explain further, previous evidence has demonstrated that individuals tend to substantially underestimate their subjective RPE ratings (7). Furthermore, based on previous data from Helms et al. (2018), when set volume is equated, training at higher RPEs tends to be superior than training at lower RPEs for strength adaptations. In this study, despite one group using RPE to prescribe load and the other group using percentages of 1RM to prescribe load, subjects provided RPE values and the investigators recorded these RPE values on every set over the course of the entire 8-week training study. The average RPE values on the squat were significantly higher (p = 0.04) for the RPE group (7.2 ± 0.3) compared to the PBT group (6.5 ± 1.0). Furthermore, the average RPE values on the bench press were significantly higher (p < 0.001) for the RPE group (7.3 ± 0.3) compared to the PBT group (5.8 ± 1.0). In the presently reviewed study, why did VBT result in significantly greater 1RM strength improvements in comparison to RPE if the percentages of 1RM for both groups were intended to be matched? The RPE group was most likely training at a lower proximity from failure and at a lower relative intensity than the intended prescription; however, the VBT group most likely training near the appropriately prescribed proximity from failure and relative intensity. Be cognizant that the intended RIR for the maximal strength block and strength speed block were 1.25 and 2.5 on average. Figure 6 illustrates what I hypothesize may have been the proximity from failure in terms of repetitions in reserve (RIR) between the VBT and RPE groups. Note that the error bars are approximately the same for both the VBT and RPE group. Why is this the case? The VBT group did not utilize individualized-load velocity profiles; thus, although on average most subjects were most likely close to the intended RIR, many were most likely somewhere above or below that intended RIR. Of course, we would expect these error bars with the RPE group since RPE scores tend to be inaccurate.

Figure 6

The second primary reason why I think VBT may outweigh RPE is due to the inherent feedback component that velocity possesses. “Landyn, you take your training so seriously” or “Landyn, why do you take your warm-ups so seriously?” or “Landyn, why do you lift so explosively during every rep”. These are common questions that I receive. I’ve always purposefully trained with intent. However, I think that incorporating velocity into training makes intentional training much more prominent. Every session, every set, every repetition is a competition between you and the velocity. Sounds silly? No, we have data supporting that velocity feedback improves both competitiveness and motivation to train (8). Finally, when in a team environment, I think that a competitive atmosphere surrounding velocity is created between teammates in an attempt to lift faster than each other. In other words, whether you train alone or with others, the inherent competitive component of VBT provides an added benefit. The third primary reason why I think that VBT provides an added benefit over RPE builds upon the previous reason. Incorporating VBT ensures that every single rep is purposefully performed with maximal concentric velocity. Training with maximal concentric velocity compared to half-maximal concentric velocity has been demonstrated to produce superior improvements in 1RM for both the squat (9; ES: 0.63 vs 0.15) and the bench press (10; 18.2 vs 9.7%). I would cautiously make the argument that on average, individuals using RPE – although they won’t be at half-maximal concentric velocity – probably don’t provide full maximal concentric velocity on every rep, especially when reps per set are higher, since they have no objective feedback regarding the velocity of each rep.

PBT vs RPE Studies

In the introduction I mentioned that there are currently 5 studies investigating either method of autoregulation (VBT or RPE). Now, let’s look at the specific findings from each study. Again, one study on each type of autoregulation method (VBT or RPE) demonstrated significantly greater strength improvements over traditional PBT. Let’s compare the findings from the presently reviewed study to those previous studies, focusing on the PBT vs RPE studies first. The squat and bench press 1RM percentage changes in the presently reviewed study from the VBT group are slightly lower than the other autoregulatory group (RPE in this case) from Helms et al. (2018) which was an 8-week long training study and from Graham & Cleather (2019) which was a 12-week long training study (Table 5). However, the squat 1RM percentage change for the RPE group is approximately one-third of that reported by Helms et al. (2018) and Graham & Cleather (2019). Additionally, the bench press 1RM percentage change for the RPE group is approximately one-half of that reported by Helms et al. (2018). Why is that? Well, its most likely because in the present study the squat was only trained once per week during block 1, and the squat wasn’t even trained during block 2, the box squat was trained. Furthermore, the bench press was trained once per week and the incline bench press was trained once per week during block 1, whereas the bench press was trained twice per week and the incline bench press was trained once per week during block 2. However, in the Helms et al. (2018) study the squat and bench press were both trained 3 times per week. Additionally, in the Graham and Cleather (2019) study the squat and the front squat were trained once per week on separate days. In other words, the higher lift-specific training frequencies and training volumes on the squat and bench press, as well as the longer block of training in the Helms et al. (2018) and Graham and Cleather (2019) study may explain the discrepancy in these findings.

Table 5. PBT vs RPE Long-Term Training Studies

PBT vs VBT Studies

The two studies on PBT vs VBT are illustrated in Table 6. Overall, the squat and bench press 1RM percentage changes from the VBT group in the presently reviewed study align with the findings from Dorrell et al. (2019), which was also a 6-week training study. However, the findings from Dorrell et al. (2019) are slightly higher, which is probably largely due to the more aggressive resistance training protocol employed. However, why did Orange et al. (2017) observe no difference between PBT and VBT? Without diving into specifics, the resistance training protocol in the Orange et al. (2017) study simply wasn’t aggressive enough to observe any difference between groups. and progressive overload was minimal.

Table 6. PBT vs VBT Long-Term Training Studies

Future Directions

Now that we have a long-term training study comparing RPE to group load-velocity profiles for load prescription, the next step is to compare individualized load-velocity profiles, to individualized PBT-based training, and RPE-based training. Realistically, someone is probably conducting a study similar to this somewhere, and we just don’t know it yet. I know this presently reviewed study was one long awaited, but nobody knew when it was coming. My hypothesis of the results of an 8-week longitudinal resistance training study comparing these three methods of load autoregulation are outlined in Figure 7. To clarify, I don’t think that the subjects should train at a prescribed 8 RPE (2 RIR) for the entirety of the study, rather I’ve simply presented that here for ease of interpretation. I think that the individualized VBT group would be nearly spot on every single week with the prescribed RIR. I think that the RPE group would typically tend to underestimate their RIR on average. However, since most subjects obtained for studies are unfamiliar with the RIR-based RPE scale prior to participation, their subjective RPE ratings may improve slightly over time and they may get closer to the intended prescribed RIR towards the end of the study, but I still think that this would be very far off. Finally, I think that the individualized PBT group would be very close to their RIR at the beginning; however, as the study ensued they would most likely be at increasingly greater RIR as their predetermined 1RM exceeded their actual 1RM. Overall, I think that strength adaptations would be significantly greater for VBT over both RPE and individualized PBT. Furthermore, I think that RPE would be slightly superior to individualized PBT, but with no statistically significant difference between them.

Figure 7

Practical Applications

Conceptual. There’s that word again. Remember, this study simply provides us with the concept that VBT may have an edge over RPE. With that said, based on my experience as both a student and researcher as well as a coach and athlete I think that the “optimal” model for an individualized and autoregulated approach is a conceptual framework integrating VBT, RPE, and % of 1RM. If you’re interested in how to develop this model for powerlifting and practically apply it into your own training, please check out my Original Seminar. If you enjoyed the Original Seminar and are seeking something more in depth, please check out my Seminar Series.

Summary

There’s not too much else to say; velocity podiumed on top in this study. A concluding summary of the advantages and limitations of this study can be seen in table 7 and table 8, respectively.

Table 7: Advantages

Table 8: Limitations

Key Takeaways

1. In the first-ever study to compare velocity- vs RPE-based load prescription on 1RM strength improvements, velocity was clearly the champion
2. There are several probable explanations as to why velocity beat out RPE in this study: closer proximity to failure, more intentional training, and faster average concentric velocity
3. Athletes should develop their own individualized load-velocity profiles integrating PBT, RPE, and VBT for optimal performance outcomes

References

1. Shattock, K, and Tee, JC. Autoregulation in resistance training: a comparison of subjective versus objective methods. The Journal of Strength and Conditioning Research [Epub ahead of print], 2020.
2. Helms, ER, Byrnes, RK, Cooke, DM, Haischer, MH, Carzoli, JP, Johnson, TK, Cross, MR, Cronin, JB, Storey, AG, and Zourdos, MC. RPE vs percentage 1RM loading in periodized programs matched for sets and repetitions. Frontiers in Physiology 9: 247, 2018.
3. Graham, T, and Cleather, DJ. Autoregulation by “repetitions in reserve” leads to greater improvements in strength over a 12-week training program than fixed loading. The Journal of Strength and Conditioning Research, [Epub ahead of print], 2019.
4. Dorrell, H, Gee, TI, and Smith, MF. Comparison of velocity-based and traditional percentage-based loading methods on maximal strength and power adaptations. The Journal of Strength and Conditioning Research 34(1): 46 – 53, 2020.
5. Orange, ST, Metcalfe, JW, Robinson, A, Applegarth, MJ, and Liefeith, A. Effects of in-season velocity- versus percentage-based training in academy rugby league players. International Journal of Sports Physiology and Performance Oct 30: 1 – 8, 2019.
6. Helms, ER, Storey, AG, Cross, MR, Brown, SR, Lenetsky, S, Ramsay, H, Dillen, C, and Zourdos, MC. RPE and velocity relationships for the back squat, bench press, and deadlift in powerlifters. The Journal of Strength and Conditioning Research 31(2): 292 – 297, 2017
7. Zourdos, MC, Goldsmith, JA, Helms, ER, Trepeck, C, Halle, JL Mendez, KM, Cooke, DM, Haischer, MH, Sousa, CA, Klemp, A, and Byrnes, RK. Proximity to failure and total repetitions performed in a set influences accuracy of intraset repetitions in reserve-based rating of perceived exertion. The Journal of Strength and Conditioning Research [Epub ahead of print], 2019.
8. Weakley, JJS, Wilson, KM, Till, K, Read, DB, Darrall-Jones, J, Roe, GAB, Phibbs, PJ, and Jones, B. Visual feedback attenuates mean concentric barbell velocity loss and improves motivation, competitiveness, and perceived workload in male adolescent males. The Journal of Strength and Conditioning Research, 33(9), 2019.
9. Pareja-Blanco, F, Rodriguez-Rosell, D, Sanchez-Medina, L, Gorostiaga, EM, and Gonzalez-Badillo, JJ. Effect of movement velocity during resistance training on neuromuscular performance. International Journal of Sports Medicine 35(11), 916 – 924.
10. Gonzalez-Badillo, JJ, Rodriguez-Rosell, D, Sanchez-Medina, L, Gorostiaga, EM, and Pareja-Blanco, F. Maximal intended velocity training induces greater gains in bench press performance than deliberately slower half-velocity training. European Journal of Sports Science 14(8), 772 – 781.