BazValle, E., FontesVillalba, M., SantosConcejero, J. (2021). Total Number of Sets as a Training Volume Quantification Method for Muscle Hypertrophy: A Systematic Review. Journal of Strength Conditioning Research, 35(3), 870878.2.3. Brigatto, F. A., Lima, L. E. M., Germano, M. D., Aoki, M. S., Braz, T. V., Lopez, C. R. (2019). High Resistance Training Volume Enhances Muscle Thickness in ResistanceTrained Men. Journal of Strength Conditioning Research.4. Duchateau, J., Semmler, J. G., Enoka, R. M. (2006). Training Adaptations in the Behaviour of Human Motor Units. Journal of Applied Physiology, 101(6), 17661775.
CREATED BY FLOW HIGH PERFORMANCE 2ND EDITION HYPERTROPHY TRAINING MANUAL AN EVIDENCE-BASED GUIDE TO MAXIMISE MUSCLE GROWTH HYPERTROPHY TRAINING MANUAL (2ND EDITION) CONTENTS PROXIMITY TO FAILURE - - QUANTIFYING PROXIMITY TO FAILURE - - - - - - - - - - - - ACCURACY - - - - - - - - - TECHNIQUE - - - - - - - - - SET BY SET - - - - - - - - - - - - - - - - ‘ALL OR NOTHING’ PRINCIPLE - - - - - - - SIZE PRINCIPLE - - - - - - - - - - - MOTOR UNIT RECRUITMENT - - PROXIMITY TO FAILURE & HYPERTROPHY FAILURE VS NON-FAILURE - - - - - - - 10 REP RANGES & LOAD - - - - - - - - 10 EXERCISE SELECTION - - - - - - - - 11 - - - - - - - 13 MOTOR UNIT RECRUITMENT - - - - - - - 14 TOO LIGHT & TOO HEAVY - - - - - - - - 15 COMPOUND VS ISOLATION LIFTS - - - - - - - 15 JOINT HEALTH REP RANGES & LOAD - - - - - - - - - - - 16 - - - - - - - - - 17 - - - - - - - - 18 VOLUME LOAD - - - - - - - - 18 NUMBER OF SETS - - - - - - - - 18 VOLUME & HYPERTROPHY - - - - - - - - 18 INDIVIDUAL RESPONSE - - - - - - - 20 - - - - - - - - 21 JOINT TOLERANCE - - - - - - - - 21 SYSTEMIC FATIGUE - - - - - - - - 22 PRACTICALITY - - - - - - - - - 22 - - - - - - - - 22 - - - - - - - - 24 VOLUME - - QUANTIFYING VOLUME LIMITING FACTORS - VOLUME ALLOCATION FREQUENCY 2|Page - - FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) FREQUENCY & VOLUME - - - - - - - 25 DIRECT VS INDIRECT TRAINING - - - - - - - 25 FREQUENCY & HYPERTROPHY - - - - - - - 25 INDIRECT INFLUENCE - - - - - - - - 26 VOLUME - - - - - - - - 26 LIFTING PERFORMANCE - - - - - - - 27 INJURY RISK - - - - - - - - - 28 EXERCISE SELECTION - - - - - - - - - 29 ANATOMY & BIOMECHANICS - - - - - - - 30 COMPOUND VS ISOLATION LIFTS - - - - - - - 30 - - COMPOUND LIFTS - - - - - - - - 30 ISOLATION LIFTS - - - - - - - - 30 - - - - - - - 31 STIMULUS-TO-FATIGUE RATIO STIMULUS - - - - - - - - - 32 FATIGUE - - - - - - - - - 32 MUSCLE RANGE OF MOTION - - - - - - - 32 MUSCLE LENGTH - - - - - - - - 33 - - - - - - - - 34 - - - - - - - - 34 - - - - - - - - - 36 - - - - - - - - - 37 EXERCISE ORDER & HYPERTROPHY - - - - - - 37 COMPOUND VS ISOLATION LIFTS - - - - - - 37 LARGE VS SMALL MUSCLES - - - - - - - 37 PRE-EXHAUSTION - - - - - - - - 38 - - - - - - - - 39 LIFTING PERFORMANCE - - - - - - - 39 JOINT STRESS - - - - - - - - - 40 STRENGTH GAINS - - - - - - - - 40 - - - - - - - - - 41 - - - - - - - - - 42 TENSION CURVES - PERSONAL PREFERENCE EXERCISE ORDER ACUTE EFFECTS INDIRECT EFFECTS - INTERSET REST - ACUTE EFFECTS 3|Page FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) INTERSET REST & HYPERTROPHY - - - - - - - 42 LIFTING PERFORMANCE - - - - - - - 42 METABOLIC STRESS - - - - - - - - 43 ANABOLIC HORMONES - - - - - - - 45 PRACTICAL CONSIDERATIONS - - - - - - - 45 TIME EFFICIENCY - - - - - - - - 45 JOINT STRESS - - - - - - - - - 46 EXERCISE SELECTION - - - - - - - - 46 - - - - - - - 48 REFERENCES 4|Page - - - FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) PROXIMITY TO FAILURE 5|Page FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) QUANTIFYING PROXIMITY TO FAILURE Proximity to failure in the simplest sense refers to how close a set is taken to failure This can be quantified using the Reps in Reserve (RIR) or Rate of Perceived Exertion (RPE) scales (Table 1.1) These are subjective scales that require trainees to judge how many reps they could have performed before failure Therefore, it is a subjective estimation of proximity to failure and may be influenced by many individual factors Both scales quantify proximity to failure in the same way, they are just different numerical systems RATE OF PERCEIVED EXERTION (RPE) REPS IN RESERVE (RIR) MEANING 10 NO MORE REPS COULD HAVE BEEN PERFORMED 1 MORE REP COULD HAVE BEEN PERFORMED 2 MORE REP COULD HAVE BEEN PERFORMED 3 MORE REP COULD HAVE BEEN PERFORMED 4 MORE REP COULD HAVE BEEN PERFORMED 5 MORE REP COULD HAVE BEEN PERFORMED 6 MORE REP COULD HAVE BEEN PERFORMED 7 MORE REP COULD HAVE BEEN PERFORMED 8 MORE REP COULD HAVE BEEN PERFORMED 9 MORE REP COULD HAVE BEEN PERFORMED TABLE 1.1: RPE & RIR SCALES ACCURACY Several studies have investigated the validity of these scales with all studies finding positive results This study (Zourdos et al., 2021) found that when performing the squat with 70% 1RM to failure, trainees were accurately able to predict repetition in reserve using the RPE scale It was also found that as trainees got closer to failure, repetition in reserve predictions were more accurate There also seemed to be some 6|Page FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) individual variation in how accurate trainees were able to judge proximity to failure, which was not related to training experience Furthermore, this study (Helms et al., 2017) explored the accuracy of using the RPE scale in powerlifters performing the squat, bench press, and deadlift Overall, trainees could accurately self-select loads to meet a prescribed RPE It was also found that the accuracy of these predictions was increased when sets were taken closer to failure, and when trainees had been using the scale for multiple successive weeks Therefore, the RIR and RPE scales seem to be valid tools to assess proximity to failure It also seems that estimations are more accurate as sets are taken closer to failure, and as trainees accumulate experience using the scales TECHNIQUE Proximity to failure also depends on lifting technique For hypertrophy training, trainees generally want to use a technique that maximally stresses the target muscle, not necessarily the technique that allows us to lift the most weight Therefore, if technique deviates, trainees can probably perform more reps or load compared with strict technique For example, when a trainee is getting close to failure in a set of biceps curls with strict form, if they start to swing the weight using momentum, then they can probably perform more reps than if they kept the technique strict This has implications for proximity to failure as it is relative to the technique used In other words, trainees should never break their form at the expense of increasing reps performed SET BY SET Proximity to failure is also independent of each set This is because workouts are not performed in a ‘vacuum’ so to speak One set will induce fatigue, which will impact the following sets and following exercises Therefore, performance will likely decrease from set to set, and throughout the course of a workout For example, let’s say a trainee performs three sets of bench press with a load of 70kg and takes each set to a proximity to failure of two reps in reserve In their first set, 10 reps may be performed in a fresh state In the second set, reps may be performed with the same load with two reps in reserve In the third set, they may only perform reps with the same load and same proximity to failure As the trainee becomes more fatigued with each set, performance starts to decline (Table 1.2) If this trainee were to perform 10 reps on each set, they would end up training at a closer proximity to failure with each successive set 7|Page FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) TABLE 1.2: PERFORMANCE DECLINE WITH SUBSEQUENT SETS MOTOR UNIT RECRUITMENT ‘Motor unit’ is a collective term to describe a motor neuron and the muscle fibres that it innervates Each muscle generally has multiple thousand muscle fibres and hundreds of motor neurons Each motor neuron is responsible for the control and contraction of the specific muscle fibres that it innervates Some muscle fibres are larger and stronger which are often referred to as ‘fast-twitch’ or ‘type 2’ fibres Other fibres are smaller and weaker but have greater endurance capacity, which are often referred to as ‘slow-twitch’ or ‘type 1’ fibres Fast-twitch fibres and their associated motor neurons are referred to as ‘high-threshold’ motor units, while slow-twitch fibres and their associated motor neurons are referred to as ‘low-threshold’ motor units ‘ALL OR NOTHING’ PRINCIPLE Motor units are recruited based on force requirements Greater force demands require more motor units to be innervated, while lower force demands require fewer motor units to be innervated The strength of the neural impulse does not change with the magnitude of force requirements, rather the number of motor units recruited will be adjusted This is known as the ‘all or nothing’ principle of motor unit recruitment This has implications for resistance training and hypertrophy adaptations When a lighter load is used, a smaller portion of motor units will be recruited since force demands are lower When a heavier load is used, a larger portion of motor units will be recruited since force demands are greater Therefore, fewer muscle fibres are initially trained using lighter loads, while more muscle fibres are initially trained using heavier loads 8|Page FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) SIZE PRINCIPLE The order of motor unit recruitment follows what is known as ‘Henneman’s Size Principle’ According to this research review (Mendell, 2005), the size principle suggests that low-threshold motor units are always recruited first, while highthreshold motor units are only recruited when required Therefore, if a submaximal exercise is performed until exhaustion, only low-threshold motor units will be recruited initially, and high-threshold motor units will contribute more as the exercise nears exhaustion By the end of the exercise bout, all motor units will be recruited to contribute to force production (Figure 1.1) FIGURE 1.1: HENNEMAN’S SIZE PRINCIPLE Concerning resistance training, this determines the amount and type of muscle fibres that are trained According to this research review (Duchateau et al., 2006), all motor units are recruited from the first repetition with loads of approximately 85% 1RM and greater, although this varies between muscles This means that when loads are lighter than this approximate threshold, not all muscle fibres will be involved from the start of the set However, this study (Morton et al., 2019) showed similar type-2 muscle activation when performing leg extension with 30% or 80% 1RM, when sets were taken to failure This suggests that although heavier loads will recruit more muscle fibres initially, all muscle fibres will eventually be recruited and trained when sets are taken close enough to failure PROXIMITY TO FAILURE & HYPERTROPHY There is no ‘optimal’ proximity to failure trainees should aim to achieve, rather it depends on several factors 9|Page FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) FAILURE VS NON-FAILURE First, is a simple binary decision: should we take sets to complete failure, or should we leave reps in reserve? This meta-analysis (Grgic et al., 2021) found no significant difference in muscle growth when comparing training to failure versus non-failure Although these results were non-significant, there did seem to be a slight benefit in favour of training to failure on a set-by-set basis When all other variables are equated, training to failure seems to be more hypertrophic than non-failure training However, in practice, trainees generally perform an entire workout in the gym rather than a single exercise Therefore, the indirect influence of training to failure on muscle growth should also be considered Frequent or inappropriate training to failure may result in excessive fatigue For example, training to failure with exercises performed at the beginning of the session may carry fatigue into the rest of the workout This may lead to a less productive training session and may inhibit the performance of subsequent sessions REP RANGES & LOAD How close a set is taken to failure will also depend on the rep ranges and loads used According to the principles of motor unit recruitment, heavier loads will involve more muscle fibres earlier in the set, while lighter loads will only recruit slow-twitch muscle fibres initially However, to maximise hypertrophy, all muscle fibres need to be recruited and trained to induce adaption This study (Lasevicius et al., 2019) compared performing leg extensions with different loads and different proximities to failure Subjects trained one limb to failure and the other limb with approximately 3-4 repetitions in reserve One group of subjects used a load of 30% 1RM and another group used a load of 80% 1RM It was found that training to failure with either load resulted in similar hypertrophy Similar hypertrophy was also seen between the limbs using 80% 1RM despite the difference in proximity to failure However, the limb training to failure using 30% 1RM saw significantly greater muscle growth than the limb training further from failure (Figure 1.2) It therefore seems that when training with heavier loads, sets not need to be taken as close to failure to elicit significant muscle hypertrophy Alternatively, lighter loads probably need to be taken closer to failure to ensure all muscle fibres are stressed, thus maximising hypertrophy adaptations 10 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) EXERCISE ORDER 36 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) Exercise order refers to the sequence of exercises within an individual training session However, exercise order is a somewhat nuanced topic This is because there are many ways to structure a training session, which makes it difficult to directly compare different strategies In an individual training session, trainees may perform anywhere between 3-6 exercises, and train either one muscle group specifically, or train the full body in a workout Therefore, it is difficult to isolate certain variables and infer results to practice ACUTE EFFECTS The main influence exercise order will have in a training session is effects on short-term fatigue Trainees will be in the least fatigued state for the exercises performed first in the session, and the most fatigued for the exercises at the end of the training session Therefore, lifting performance is likely to be superior for the exercises at the start of the session, and inhibited for the exercises performed towards the end of the session However, this may only be the case if the same muscle group is trained with multiple exercises in the same session If each exercise trains different muscle groups, then fatigue of subsequent exercises will not be as significant So once again, context plays an important role when discussing exercise order EXERCISE ORDER & HYPERTROPHY Exercise order may influence fatigue and therefore impact lifting performance However, how does this influence actual muscle growth in an applied resistance training program? COMPOUND VS ISOLATION LIFTS It is commonly advised that compound lifts should be performed first in a session, and isolation lifts last However, does this order influence hypertrophy outcomes? This meta-analysis (Nunes et al., 2021), examined the research comparing the effects of performing compound versus isolation lifts first in a training session The researchers found that gains in maximal strength were superior in the exercises performed first in the session, regardless of whether this was a compound or isolation lift However, it was found that hypertrophy outcomes were similar, regardless of whether compound or isolation lifts were performed first in the session LARGE VS SMALL MUSCLES It is commonly advised that larger muscle groups should be trained first, and smaller muscle groups last However, does this order influence hypertrophy outcomes? Research on this topic is scarce, but two primary studies have investigated this topic This study (Simão et al., 2010) compared hypertrophy outcomes between training 37 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) larger muscles followed by smaller muscles, versus training smaller muscle followed by larger muscles One group performed the following exercise sequence: bench press, lat pulldown, triceps extension, and bicep curl Another group performed the same resistance training program with the opposite exercise order: bicep curls, triceps extension, lat pulldown, and bench press Once again, it was found that strength gains were superior for the exercises performed first in the session, while there were no clear trends observed for hypertrophy outcomes Another study (Spineti et al., 2010) used an almost identical training protocol One group performed the bench press, lat pulldown, triceps extension, and biceps curls in that order Another group performed the same resistance training program with the opposite exercise order: bicep curls, triceps extension, lat pulldown, and bench press Just like the rest of the research on exercise order, it was found that strength gains were superior for the exercises performed first in the session, while there was no significant difference in hypertrophy outcomes (Figure 6.1) FIGURE 6.1: CHANGE IN MUSCLE VOLUME (SPINETI ET AL., 2010) PRE-EXHAUSTION A pre-exhaust or pre-fatigue strategy is when a trainee intentionally fatigues a specific muscle group before performing another exercise involving that muscle This is usually accomplished by performing an isolation lift for a specific muscle before a compound lift, for which the fatigued muscle is a prime mover This study (Trinidade et al., 2019) compared the effects of a pre-exhaust strategy versus a traditional training protocol on strength and hypertrophy outcomes Subjects performed three sets of leg press to failure with 75% 1RM, once per week 38 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) One group performed the three sets alone, while another group pre-exhausted the quadriceps before the leg press protocol In the pre-exhaust group, subjects performed one set of leg extensions to failure with 20% 1RM immediately before the leg press protocol After nine weeks of training, both groups saw significant glute and quad hypertrophy, with no significant differences between protocols However, volume load (sets x reps x load) was much higher in the traditional protocol compared with the pre-exhaust strategy (Figure 6.2) These results suggest that pre-exhausting a muscle group may be equally effective at promoting muscle growth while allowing trainees to train with less total tonnage FIGURE 6.2: VOLUME LOAD (TRINIDADE ET AL., 2019) INDIRECT EFFECTS Current research suggests that the order of exercises within a training session does not seem to have a significant influence on muscle growth directly However, exercise order may hypothetically influence long-term hypertrophy outcomes through indirect mechanisms LIFTING PERFORMANCE As was established in some of these studies, volume load was influenced by exercise order Generally, if larger muscle groups are trained with compound lifts earlier in the session, more total volume load will be performed in that session This is because if a smaller isolation lift is performed before a compound lift involving that muscle group, that specific muscle will be more fatigued and limit performance of the compound exercise 39 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) While lifting performance didn’t seem to impact hypertrophy outcomes with different exercise orders, limiting volume load could potentially limit long-term hypertrophy outcomes While this is speculative, training with greater volume load over time may result in more favourable muscle growth compared with training with lower volume loads JOINT STRESS As mentioned, exercise order can influence volume load If trainees can achieve similar hypertrophy outcomes with less volume load, this may alleviate joint stress to some extent If trainees can lift with lighter loads or fewer repetitions, it will likely reduce the risk of joint pain or irritation This may be favourable for those who have particularly irritable joints or connective tissue due to current or past injury In this case, trainees may want to pre-fatigue a muscle using an isolation lift before a compound lift to limit volume load and therefore limit joint stress This can alleviate pain at times when joints are particularly irritable, while still resulting in equivalent hypertrophy outcomes, at least in the short-to-moderate term STRENGTH GAINS While this book is specifically focussing on the effects of training to maximise muscle hypertrophy, it should be noted that exercise order has a significant effect on strength gains The exercises performed earlier in a training session experience the greatest strength gains Greater strength gains may result in greater muscle growth over a long-term perspective, although this is highly speculative More importantly, many trainees have simultaneous strength goals in addition to their hypertrophy training Therefore, to maximise strength, trainees should perform specific strength lifts first in the training session PRACTICAL GUIDELINES • It is difficult to draw strong conclusions regarding the effect of exercise order on muscle hypertrophy from the current research • It seems that exercise order doesn’t have a significantly influence on muscle growth in the short-to-moderate term • Exercises performed first in a training session clearly experience the greatest strength gains • Pre-fatiguing a muscle may result in similar hypertrophy outcomes while alleviating joint stress 40 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) INTERSET REST 41 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) Rest periods are simply the time taken between each set This is usually passive rest, where no deliberate activity is performed The trainee usually sits down somewhere and waits until it is time for them to perform their next set Therefore, this can be more accurately defined as interset rest ACUTE EFFECTS Interset rest influences acute fatigue, which impacts lifting performance of subsequent sets The amount of rest allowed between each set determines how much time a trainee has to dissipate fatigue before the following set Naturally, shorter rest periods limit how much weight or reps we can lift in the next set, while longer rest periods allow us to lift heavier loads or perform more reps However, it is unclear if these influences on lifting performance translate to a difference in muscle growth INTERSET REST & HYPERTROPHY The best current evidence on this topic is this systematic review (Grgic et al., 2017) This review analysed the current research comparing interset rest periods of less than 60 seconds versus rest periods of greater than 60 seconds The researchers concluded that both short and long rest periods are similarly effective and promoting muscle growth, although there is potentially a slight advantage for longer rest periods Looking at the entire body of research, there seems to be a slight trend in favour of longer rest periods, although it is unclear why this is the case LIFTING PERFORMANCE The first and most probable reason that longer rest periods seem to be slightly superior is due to its influence on lifting performance As discussed, longer rest periods allow greater fatigue dissipation and therefore superior lifting performance This study (Schoenfeld et al., 2016) compared the effects of training with short versus long rest periods on hypertrophy outcomes Subjects performed a full-body resistance training program three times per week for eight weeks Trainees performed three sets of 8-12 reps to failure of the following exercises: back squat, leg press, leg extension, bench press, military press, lat pulldown, and seated cable row One group trained with one-minute rest between sets, while another group trained with three minutes rest between sets At the end of the training protocol, the long-rest group saw superior hypertrophy of all muscles measured compared with the short-rest group This is potentially due to the differences in lifting performance because of the different interest rest periods Naturally, the long-rest group trained with greater volume-loads throughout the training program (Figure 42 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) 7.1) This suggests that longer rest periods may have a slight hypertrophic advantage by allowing lifters to perform more repetitions or lift more weight per set FIGURE 7.1: VOLUME LOAD (SCHOENFELD ET AL., 2016) METABOLIC STRESS Another potential mechanism influencing the hypertrophic effects of inteset rest is metabolic stress Shorter rest periods result in a greater accumulation of metabolic by-products in the working muscles The aforementioned systematic review (Grgic et al., 2017) prosed this theoretical graph exploring the interplay of the hypertrophy mechanisms, and how they change with varying rest periods (Figure 7.2) This graph suggests that metabolic stress is greater with shorter rest periods, while mechanical tension and muscle damage are maximised with longer rest periods 43 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) FIGURE 7.2: INFLUENCE OF INTERSET REST ON HYPERTROPHY MECHANISMS (GRGIC ET AL., 2017) There is some evidence suggesting that hypertrophy outcomes may be superior when metabolic stress is maximised via limiting interset rest This study (Fink et al., 2018) compared the effects of arm training with a traditional versus a metabolite style technique Trainees performed three sets of three bicep exercises – barbell curl, preacher curl, and hammer curl – and three triceps exercises – close grip bench press, French press, and dumbbell triceps extensions One group of subjects trained with an 8RM load with three minutes rest between sets, while another group trained with a 20RM load with 30 seconds rest After the 8-week training protocol, the group training with short rest periods and lighter loads saw superior increases in cross-sectional area of the upper arms This may potentially be due to differences in metabolic stress between conditions The short-rest, light-load training group experienced greater acute increases in muscle thickness post-training In simple terms, the group training with lighter loads and shorter rest periods experienced a greater arm pump While post-exercise muscle thickness is not a direct measure of metabolic stress, it indicates that there was a greater accumulation of fluids in the trained muscles, which is likely due to metabolic by-products to some extent Another study (Fink et al., 2018) compared the effects of traditional training versus drop-sets on triceps hypertrophy Trainees performed three sets of triceps pushdowns 2x per week for weeks, with all sets taken to failure One group trained with a more traditional protocol consisting of three sets with a 12RM load, with 90 seconds interset rest The other group performed the first set with a 12RM load, and two subsequent sets with a progressive 20% drop in load in immediate succession It was found that the drop-set protocol resulted in superior triceps 44 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) growth compared with the traditional training routine This also suggests that these results may be due to differences in metabolic stress between training protocols Once again, muscle thickness – an indicator of swelling and metabolic stress – was significantly greater immediately post-training with the drop-sets protocol ANABOLIC HORMONES Another potential hypertrophy mechanism that may be influenced by interset rest is the anabolic hormone response This study (Buresh et al., 2009) compared the hormonal response to resistance training with different interset rest periods Subjects performed the same 10-week resistance training protocol, following an upper-lower split 2x per week One group trained with 2.5 minutes rest between sets, while another group trained with oneminute rest The short-rest group experienced greater elevations in the anabolic hormones of testosterone and growth hormone immediately post-training in the initial stages of the training program However, by the fifth week of training, these hormonal differences diminished (Figure 7.3) Furthermore, there was no correlation found between post-exercise hormone levels and muscle growth It was found that the longer-rest protocol resulted in superior increases in arm and thigh muscle growth Therefore, the initial differences in anabolic hormones had no impact on hypertrophy outcomes anyway FIGURE 7.3: POST-EXERCISE TESTOSTERONE & GROWTH HORMONE (BURESH ET AL., 2009) 45 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) PRACTICAL CONSIDERATIONS It seems that the research is somewhat nuanced regarding the effects of rest periods on hypertrophy The mechanisms responsible for the influence of rest periods on hypertrophy are not fully understood However, there are also other practical considerations which will determine how long trainees rest between sets TIME EFFICIENCY Trainees may be limited in time available to train, or they simply don’t want to spend all day in the gym Therefore, it is relevant to discuss how trainees can make their training sessions as time-efficient as possible Shorter rest periods are a much more efficient way to train Despite the evidence showing that shorter rest periods may be slightly less hypertrophic per set compared with longer rest periods, it is a disproportionate amount This means that even if rest periods are significantly reduced, the hypertrophy response may only be inhibited by a small percentage Therefore, trainees can drastically reduce training time in the gym, with only a small compromise in muscle growth Furthermore, if trainees want to maximise hypertrophy, an additional 1-2 sets for each exercise can be performed to make up for the inhibited response Ultimately, shorter rest periods allow more volume to be performed in the same amount of time, or the same volume to be performed in a shorter time JOINT STRESS As discussed, longer rest periods allow trainees to lift more weight or perform more reps in subsequent sets While this may be slightly more hypertrophic in most cases, it is also likely to result in greater joint stress Since each set is slightly more stressful on the joints involved, it may limit the overall amount of volume that can be tolerated for any specific joint Pushing beyond this volume threshold with heavier loads may result in joint pain or irritation over time Training with shorter interset rest will limit relative loads lifted, which will likely induce less joint stress per set This will allow trainees to perform more volume across the week before experiencing a pain response EXERCISE SELECTION It may be more suitable to implement longer or shorter rest periods, based on the specific nature of the exercise To maximise hypertrophy, the target muscle should be the limiting factor for the performance of each set This is to maximise stress of the target muscle, for adaptations to take place in that tissue Rest periods play a role in what system is the limiting factor since they influence fatigue of other systems 46 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) in addition to the target muscle More specifically, rest periods will influence fatigue of the cardiovascular system, and other accessory muscles involved in the lift Therefore, some exercises may be limited by these systems before the target muscle if rest periods are too short Generally, compound lifts with high stability demands require longer interset rest to ensure other systems recover in addition to the target muscle Isolation lifts with low stability demands can usually get away with shorter rest periods because performance will only be limited by the target muscle, not any other systems PRACTICAL GUIDELINES • Longer interset rest periods seem to be slightly more hypertrophic in most contexts • Shorter interset rest periods are more time-efficient and likely less stressful on the joints and connective tissue • Free-weight, compound lifts generally require longer interset rest to ensure the cardiovascular system and accessory muscles won’t limit performance before the target muscle • Isolation lifts can involve shorter rest periods because the target muscle will almost always be the limiting factor regardless of how short rest periods are (Table 7.1) TABLE 7.1: RECOMMENDED INTERSET REST PERIODS 47 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) REFERENCES Baz-Valle, E., 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PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) PROXIMITY TO FAILURE 5|Page FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) QUANTIFYING PROXIMITY TO FAILURE Proximity to failure... PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) EXERCISE SELECTION 29 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) Resistance training is simply a means to stress... HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) FREQUENCY 24 | P a g e FLOW HIGH PERFORMANCE HYPERTROPHY TRAINING MANUAL (2ND EDITION) Training frequency refers to how often a muscle is