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3/1/2023 Literature Review

The Effect of Load and Volume Autoregulation on Muscular Strength and Hypertrophy


This study suggested what most people already thought through practical application, RPE, RIR and objective velocity appeared to have similar impact on strength gains overall. Velocity thresholds from 20-25% seemed to be the best for improvements overall in strength, and was equal to velocity loss >25% showed improvements in hypertrophy. However, velocity loss of 25% or more was superior for hypertrophy than those under 20% but was likely related to volume performed in the >25% loss groups.

The idea here with autoregulation we want to match fitness and fatigue on a given day so we are not under dosing a fitness generating stimulus on some days, but on days we don’t perform well we could be overdosing creating more fatigue than necessary. This might be overall most important when it comes to strength programming.

Velocity is often used either as an average concentric velocity within a range during sets, or is based on the first rep average. This is how it is most often used practically. So termination of a set or sets happens when you cannot achieve a velocity within a certain range, or your first rep is not within that range. Velocities seem to be accurate for many lifts from 20-90% 1RM for that day.

It seems that lower velocity loss protocols are useful because it helps with fatigue mitigation and allows athletes to perform the task in a manner that maximizes high threshold motor unit recruitment.

This study also mentions that training to failure shows up a lot in prior research, we now know this isn’t necessary, and in a lot of cases might impact recovery and ability to perform more volume within a session or training week. Especially when volume is equal it doesn’t seem to make differences if we train to failure or not. Also alternative set structures like cluster sets appear to have a potential to improve hypertrophy and strength with less generation of fatigue. And that we can likely train further from failure than previously thought to stimulate hypertrophy based on newer data. Especially because mechanical tension or loads within 60-90% of 1RM help stimulate high threshold motor units from the onset of a working set which appears to be a prerequisite.

When autoregulation is applied it seems there are greater gains in strength overall relating to enhanced neuromuscular learning, as well as reduction of fatigue that doesn’t hinder performance. Especially because muscular damage causes down regulation of high threshold motor units, and motor learning, and may impact skill acquisition. So alternative set structures are an interesting in regards to our main coaching goals.

Also accuracy of RPE/RIR etc needs practice but the closer we are to failure the more accurate RPE tends to be, and seems to drop off under RPE 6.

Again when volume is equated hypertrophy seems to be similar between traditional training and cluster sets, however cluster sets are usually less fatiguing which may benefit strength gains, or help when deep in prep, or dealing with injuries.

It seems also that high threshold motor units are primarily activated maximally at 70% 1RM which means we may see significant increase in mechanical tension which is the main driver of hypertrophy on top of volume. But having higher RPE or velocity losses also help with metabolite accumulation which could aid hypertrophy over time as well.

However some of these differences may be negligible as we will be accounting for volume in programming, because usually we are trying to build a program based on sets per week, accumulation of volume, within time constraints. If someone has no time constraints we may see maximal strength using alternate set structures, because they can perform more volume, and recover from that volume better.

Hickmott LM, Chilibeck PD, Shaw KA, Butcher SJ. The Effect of Load and Volume Autoregulation on Muscular Strength and Hypertrophy: A Systematic Review and Meta-Analysis. Sports Med Open. 2022 Jan 15;8(1):9. doi: 10.1186/s40798-021-00404-9. PMID: 35038063; PMCID: PMC8762534.

Concurrent Aerobic and Strength Training for Skeletal Muscle Size and Function


Cardio doesn’t seem to interfere with long term strength and hypertrophy, but does seem to impact power output in most cases. For example, it seems to limit explosiveness like with jumping.

It seems to remain good practice to split up resistance training and higher levels of cardio to maximize recovery and reduce interference. The mode of cardio seems to make a difference, IE if you perform leg based cardio it will impact your legs more if you have a resistance training session within 24 hours and the same with upper body.

The main thing that can limit our progress would be performing intense cardio within 24 hours of lifting, and spreading ourselves too thin with general recovery. Since the interference effect does happen but is often based on the dose of the cardio being performed. Doses of cardio significantly exceeding 30 minutes seem to have a larger impact on strength and muscle growth due to recovery.

Also the mode of cardio matters, for example running and sprinting will have a higher recovery cost than biking due to the significant eccentric contractions when running.

If you are seeking to push certain adaptations to their maximal it may be beneficial to focus on those for a while and reduce the volume of the other modality to a level where you are maintaining progress. You can push both at the same time but unless they are split up by 3-24 hours and recovery is managed really well you will probably at some point see diminishing returns.

Schumann M, Feuerbacher JF, Sünkeler M, Freitag N, Rønnestad BR, Doma K, Lundberg TR. Compatibility of Concurrent Aerobic and Strength Training for Skeletal Muscle Size and Function: An Updated Systematic Review and Meta-Analysis. Sports Med. 2022 Mar;52(3):601-612. doi: 10.1007/s40279-021-01587-7. Epub 2021 Nov 10. PMID: 34757594; PMCID: PMC8891239.

Autoregulation in Resistance Training


There seems to be a lack of a framework in research on the implementation of autoregulation techniques. The lack of consistent definitions and interchanging of terms can make research and then application to practice challenging.

The main idea as we know is that the fitness and fatigue model of training doesn’t exist in a vacuum. We understand that sleep, nutrition, illness, and other factors that exist on a day to day basis can impact our overall recovery and readiness for a given session.

Autoregulation continues to rise in popularity and is sometimes seen as being more beneficial than pre-planned percentage based programs.

Especially because many training blocks and programs have been traditionally developed off of older singular baseline measurements (powerlifting training).

This can create a mismatch between the training stimulus and ability on that day. Meaning some days we may be overdosing and some days under dosing. Thus either generating more fatigue than necessary or not maximally stimulating generation of fitness.

The fitness fatigue model would say that we develop from a single bout of training two effects, fitness which is a low magnitude positive effect, and negative high magnitude fitness effect. Therefore our performance on a given day can be seen as the sum of these counteracting effects.

Newer fitness fatigue model

In session measures

RIR - exertion scale of how many repetitions away from momentary failure someone is. This measure seems to have a good relationship as well with bar velocity. This is in both experienced and novice lifters.

Again this needs practice as many individuals will overshoot RPE and rate them as lower even when they reach failure. But this is based on the traditional BORG RPE scale which doesn’t make a lot of sense for lifting

This is where you see multiple ways of utilizing autoregulation as well, as in literature they will use RIR/RPE stops as to working up towards achieving a particular RIR/RPE, or someone can perform sets until they go over that RIR/RPE, or just have fixed sets and adjust loads to match performance on that day.

Velocity based training- there is a correlation across UE and LE exercises that velocity matches certain percentages. Also velocity profiles might change day to day with fluctuations in readiness. This also allows for an objective outside measure of performance, for some people to accurately gauge readiness.

For example 80% correlates well with .45-.55 m/s so we could prescribe this range versus a fixed percent.

Velocities also seem to relate well with relationship to failure and we can implement stopping velocities, like perform sets until you cannot perform x velocity to also auto regulate volume.

This can also be used via RPE and RIR

This is how I am programming for myself using a combination of RPE and AMRAP sets to help gauge where my 1RM likely is. This then impacts % that I use going into the next block and make adjustments within block based on new performances with AMRAP sets to go up or down for the next week.

Remember autoregulation is going to be context specific, meaning our clients goals, current training age, distance from a comp prep etc will all play into how we use some of these strategies.

Greig L, Stephens Hemingway BH, Aspe RR, Cooper K, Comfort P, Swinton PA. Autoregulation in Resistance Training: Addressing the Inconsistencies. Sports Med. 2020 Nov;50(11):1873-1887. doi: 10.1007/s40279-020-01330-8. PMID: 32813181; PMCID: PMC7575491.

The cardinal exercise stopper: Muscle fatigue, muscle pain or perception of effort?


What is the limiting factor with aerobic exercise? The researchers questions what would be the main thing that lead to stopping exercise or the “cardinal exercise stopper”

Time to exhaustion (TTE) is impacted by many things. It’s normally thought that this is impacts by maximal voluntary power of a muscle require to perform the movement, the power required, and the rate of fatigue

Some think that muscle fatigue is the main reason for the cessation of exercise but newer studies might not agree

Others would say that the conscious decision to stop is made before reaching actual fatigue, and others suggest pain from exertion is the main reason people stop

Also in theory it is thought that these conscious decisions are made when the effort made by TTE tests is perceived to exceed maximum effort a person is willing to exert to succeed in the test. So motivation might also play a role here

But it seems fatigue nor muscle pain are the cardinal exercise stopper. Perception of effort appears to be the primary factor for how long someone who is motivated can sustain high intensity exercise.

So those who have a slower increase in perception of effort may have better endurance performance and take longer to reach a higher level of muscle pain at a fixed RPE

It is also likely that the motor cortex plays a role here as these areas have to adjust to muscle fatigue and this causes a greater adjustment and perception of fatigue.

So the negative effect of fatigue is mediated by the perception of effort. So any factors physiologically or psychologically that might change the perception of effort can impact endurance performance even if true fatigue is not inspired. Ie mental fatigue.

Again, it appears that this is a conscious decision making process in which perception of effort plays an important role.

Don’t be bitch *in Ukrainian accent*

Walter Staiano, Andrea Bosio, Helma M. de Morree, Ermanno Rampinini, Samuele Marcora, Chapter 11 - The cardinal exercise stopper: Muscle fatigue, muscle pain or perception of effort?, Editor(s): Samuele Marcora, Mustafa Sarkar, Progress in Brain Research, Elsevier, Volume 240, 2018, Pages 175-200, ISSN 0079-6123, ISBN 9780444641878, PMID 30390830

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