Bench Press - The Truth About the Effects of Bench Angle on Pec Activity Varies Depending on the Phase of the Lift

Bench Press - The Truth About the Effects of Bench Angle on Pec Activity Varies Depending on the Phase of the Lift

bench press build muscle chest emg incline press muscle activity pectoralis major

The bench press, in one form or another, is part of almost everyone's workout, but what's the best way to do it?

You may have seen Brad Schoenfeld's post about the just accepted study of his that confirms the well-known link between muscle activity and poundage (higher weight = higher activity | see EMG Series). Well, another recent study provides additional intricate insights into the link between muscle activity and the way you perform the bench press.

Just like Schoenfeld et al.'s study, the study compared the muscular activation during bench presses - albeit in this case that of the pectoralis major, anterior deltoid and triceps brachii during a freeweight barbell bench press performed at different angles: 0°, 30°, 45° & -15° angles, to be specific.

Want to become stronger, bigger, faster and leaner? Periodize appropriately!

30% More on the Big Three: Squat, DL, BP!

Block Periodization Done Right

Linear vs. Undulating Periodizationt

12% Body Fat in 12 Weeks W/ Periodizatoin

Detraining + Periodization - How to?

Tapering 101 - Learn How It's Done!

As the authors from the Department of Kinesiology, Cardiopulmonary and Metabolic Research Laboratory at the University of Toledo point out, this is not as "boring" as you may think it is,, as previous investigations may have systematically examined muscle activation during various bench press conditions only throughout the complete lift. Needless to say that "[d]uring any resistance exercise a complete ROM is important", but Jakob D. Lauver et al. are right to point out that there may be potentially relevant differences in the level of muscle activation over the course of the full range of motion (ROM). The latter could be significant enough to...

"[...] have the potential to attenuate any difference in muscle activation observed during the complete lift between bench angle conditions as differences in activation may have been evident throughout different time points of contractions" (Lauver. 2016). 

Accordingly, the primary purpose of the present investigation was, as Lauver et al write "to compare the changes in muscle activation at various time points across contraction phases (concentric, eccentric) during free-weight barbell bench press at varying bench angles (–15°, 0°, 30°, 45°) while maintaining the same absolute resistance load" (Lauver. 2016). The scientists hoped that the results of their study would lead to a better understanding of the effect of bench angle on muscle activation during bench press exercise and "aid in selection of variations in bench press exercise to develop upper extremity strength and musculature" (Lauver. 2016).

So, 80% = maximum activity - Why did the scientists use 65% 1RM? If Schoenfeld et al. found that you need 80% of the 1RM it may initially appear to be a methodological shortcoming to use only 65% of the 1RM. On the other hand, the fact that high loads, alone, maximize the muscle activity may nullify the significance of angle- or phase dependent differences... I cannot tell you, however, whether that's what the scientists had in mind when they decided to go for "only" 65% of the 1RM or whether they simply wanted to avoid fatigue having an effect on subsequent sets.

For their study, Lauver et al. recruited 14 healthy resistance trained men (age 21.4 ± 0.4 years) who performed one set of six repetitions for each bench press conditions at 65% one repetition maximum. As in previous studies, Lauver et al. used surface electromyography (sEMG) to quantify the muscular contraction. In contrast to previous studies, however, they analyzed the corresponding data during four parts of the lift individually - not just for the whole lift.

Figure 1: Upper and lower (U- / L-) pectoralis major activity during eccentric (UA / LA) and concentric (UB / LB) quarts of the bench press at different angles (-15°, 0°, 30° and 45° | Lauver. 2016).

This is important, because their data showed no difference during any of the bench conditions, when the scientists examining the complete contraction and/or only the concentric part (pushing the bar up) of the contraction. A different picture emerged, however, when Lauver et al. analyzed the four phases of the eccentric and concentric phase individually:

• Differences were found for 26–50% contraction for both the 30° [122.5 ± 10.1% maximal voluntary isometric contraction (MVIC)] and for 45° (124 ± 9.1% MVIC) bench condition, resulting in greater sEMG compared to horizontal (98.2 ± 5.4% MVIC) and –15 (96.1 ± 5.5% MVIC). 
• The sEMG of lower pectoralis was greater during –15° (100.4 ± 5.7% MVIC), 30° (86.6 ± 4.8% MVIC) and horizontal (100.1 ± 5.2% MVIC) bench conditions compared to the 45° (71.9 ± 4.5% MVIC) for the whole concentric contraction. 

Overall, the study results obviously still confirm what you've read previously at the SuppVersity: "[T]he use of a horizontal bench to achieve muscular activation of both the upper and lower heads of the pectoralis" (Lauver. 2016).

This doesn't mean that adding an incline press to your regimen would be useless. As Lauver et al. point out, there's still use for the incline bench press - specifically at 30°!, because it "resulted in greater muscular activation during certain time points", so that the overall results of the study suggest "that it is important to consider how muscular activation is affected at various time points when selecting bench press exercises" (Lauver. 2016).

Shoulder Presses Ain't for Delts, Only! Standing, Seated w/ BB or DB, They Also Hammer the Core, Biceps & Triceps. That's at least what a previously discussed study shows | learn more

Bottom line: The implications of the study are not 100% straight forward. But overall it appears as if there were two take home messages: (1) If you're doing just one exercise, you should stick to the flat bench (or vary cyclically). (2) If there's room for another bench press you should favor the 30° over the 45° degree bench press, because it achieves the same upper pectoralis activation as the 45° incline bench press, but a great lower pectoralis activation.

What is a bit surprising, but may be due to the differences in methodology compared to the previously cited study in the SuppVersity EMG Series is that there were no measurable advantages of the decline bench press, which may have benefited from the subjects' ability to lift more weight in previous studies. If that's the same for you, I personally wouldn't discount the decline press yet - you will, after all, probably not lift with 65% of your 1RM, right? | Comment!

References:

• Lauver, Jakob D., Trent E. Cayot, and Barry W. Scheuermann. "Influence of bench angle on upper extremity muscular activation during bench press exercise." European journal of sport science (2015): 1-8.
• Schoenfeld, Brad J; Contreras, Bret, Vigotsky, Andrew D.; et al. "Upper body muscle activation during low- versus high-load resistance exercise in the bench press." Not yet published; private communication on Facebook (2016).

Two Hours of Extra-Sleep Before Sleep Deprivation Minimize the Performance Decrements Due to 24h Sleep Deprivation

Two Hours of Extra-Sleep Before Sleep Deprivation Minimize the Performance Decrements Due to 24h Sleep Deprivation

health performance sleep sleep deficit sleep deprivation vorschlafen

If you want to practice "vorschlafen" you may have to set your alarm-clock to tell you when to go to bed.

"Vorschlafen" is the German term for getting extra sleep the nights before an event of which you know that it will leave you sleep deprived. Sounds stupid? Well, there are studies which show that increasing sleep duration for around one week may influence cognitive performance during a subsequent sleep loss period, but aside from a study on the accuracy of tennis serves (Schwartz. 2015), their practical significance for athletes is obviously limited. Why? Since your ability to focus during cognitive tasks is - as important as it is - not a reliable marker of exercise performance... or at least a very unreliable one.

Against that background it's good that in a new study from the Université de Lyon, Instead of testing cognitive performance markers such as the attention span of an individual, the researchers set out to "assess the effect of 6 nights of sleep extension on neuromuscular function and motor performance before and after [total sleep deprivation] TSD" (Arnal. 2016).

Learn more about the health effects of correct / messed up circadian rhythms

Sunlight, Bluelight, Backlight and Your Clock

Sunlight a La Carte: "Hack" Your Rhythm

Breaking the Fast to Synchronize the Clock

Fasting (Re-)Sets the Peripheral Clock

Vitamin A & Caffeine Set the Clock

Pre-Workout Supps Could Ruin Your Sleep

So what did the scientists do? Well, the subjects, twelve healthy men (age: 32.2 ± 3.9 years, weight: 75.2 ± 6.2 kg, height: 176.9 ± 6.2 cm, body mass index: 23.7 ± 1.7 kg/m², physical activity: < 4 h per week) participated in two counterbalanced experimental conditions (cross-over design):

• extended sleep aka EXT - mean (SE) h = 9.8 (0.1) time in bed and
• habitual sleep aka HAB - mean (SE) h = 8.2 (0.1) time in bed.

The two conditions were seperated by a 6-week washout period. In each condition, subjects performed six nights of either EXT or HAB followed by two days in-laboratory.

Sleep Science Update: New Insights into the Effect of a Lack of Quality Sleep on Glucose Control and Diabesity Risk | more

"Two weeks before the first phase, a familiarization night was spent in the laboratory to avoid any first-night laboratory effects. Moreover, a control week where subjects spent 8 h in bed each night was realized before the first phase to avoid starting the experiment with the subjects in sleep debt. Time in bed during the control week was checked with actigraphy (Actiwatch TM, Cambridge Neurotechnology, Cambridgeshire, UK). The first phase consisted in 5 nights at home (N1 to N5) with sleep recorded by polysomnography. In HAB, subjects were instructed to maintain their habitual sleep time and spend at least 8 h in bed (bedtime between 22:30 and 23:00 and wake up at 07:00).

In EXT, they spent 10 h in bed between 21:00 and 07:00. In both conditions, volunteers maintained a wake time of 07:00 to accustom themselves to the waking time of 07:00 used during the second laboratory phase. Volunteers were allowed to maintain their usual lifestyles but needed to return the polysomnography equipment to the laboratory every morning" (Arnal. 2016).

The second phase was conducted in the laboratory and started at 17:00 after the 5th night at home
(standardized to be on Saturday for everyone for each condition). Subjects were familiarized
with the experimental protocol between 17:00 and 20:00. The day after was considered as the
baseline day during which neuromuscular testing was performed between 17:00 and 20:00 (D0).
Neuromuscular testing was repeated at the same time of day the following day, i.e. after 34-37 h
of continuous wakefulness (D1).

Figure 1: Overview of the two phases of the experimental protocol (Arnal. 2016).

With temperature and light control, abstinence exercise, caffeine, tobacco, alcohol and other psychoactive substances 48 hours before and during the laboratory phase and standardized meals and caloric intakes (2600 kcal/day), the scientists sought to limit confounding factors.

Figure 2: The fact that the effect size was individual should not surprise you and could be due to the fact that the extra 2h in bed may not have been spent sleeping in all subjects (Arnal. 2016).

Accordingly, they are quite confident to conclude that the small, but for some of the subjects highly significant inter-treatment difference they observed, namely...

• a longer time to exhaustion in EXT compared to HAB (+3.9 ± 7.7% and +8.1 ± 12.3% at D0 and D1, respectively), as well as 
• a lower rating of perceived exertion during exercise at D2 in the EXT compared to HAB (-7.2 ± 7.5%) group 

triggered these performance benefits, of which the scientists say that it was no induced by blunted central fatigue in response to total sleep deprivation (TSD), but rather a consequence of the beneficial effect the subjects' ratings of perceived exertion in the sleep deprived state.

Figure 3: Rates of perceived exertion before and after total sleep deprivation (Arnal. 2016).

Bottom line: "Vorschlafen" works - at least in some individuals. If you scrutinize the data in Figure 2 and take a look at the average rates of perceived exertion and their large error bars in Figure 3, you will have to admit, though, that a significant effect of sleeping 2h extra before being sleep deprived cannot be guaranteed.

Speaking of sleeping: Since the subjects simply spent 2h extra in bed, we don't know whether those who didn't respond (a) even got 2h extra sleep and whether (b) this extra sleep was quality sleep. Next to potentially existing inter-individual difference in the response to "vorschlafen", methodological shortcomings of the study may thus also explain the heterogeneity of the results | Comment on Facebook!

References:

• Arnal, et al. "Sleep Extension before Sleep Loss: Effects on Performance and Neuromuscular Function." Medicine & Science in Sports & Exercise (2016): Publish Ahead of Print - DOI: 10.1249/MSS.0000000000000925
• Schwartz, Jennifer, and Richard D. Simon. "Sleep extension improves serving accuracy: A study with college varsity tennis players." Physiology & behavior 151 (2015): 541-544.

Full-Body vs. Split Workouts: Body Composition Changes Favor Volume-Equated FB Workouts in Trained Athletes

Full-Body vs. Split Workouts: Body Composition Changes Favor Volume-Equated FB Workouts in Trained Athletes

1rm bench build muscle build strength full body lose fat performance split routines split training squat training volume volume

I guess that most of you will be training according to a split workout, right? You can do so many great bench press and biceps curl variations on "International Chest + Biceps"-Monday... awesome, right? Ok, enough of the sarcasm and back to the science. In this case, a recent study by scientists from the National Research Institute in Warsaw, the Sports Performance Research Institute New Zealand, the Bond University in Australia and the University of the Sunshine Coast.

Said study was conducted by Crewther et al. and published recently in the Biology of Sport. It examined the effects of two equal-volume resistance-training protocols upon strength, body composition and salivary hormones in male rugby union players.

You can also incorporate full body training into your periodization schemes.

30% More on the Big Three: Squat, DL, BP!

Mix Things Up to Make Extra-Gains

Linear vs. Undulating Periodizationt

12% Body Fat in 12 Weeks W/ Periodizatoin

Detraining + Periodization - How to?

Tapering 101 - Learn How It's Done!

The scientists used a crossover design, involving 24 male rugby players (mean age 29.8 ± 6.8 years; height 179.5 ± 7.9 cm; body mass 92.9 ± 12.2 kg) with at least 2 years of resistance-training experience (3-4 times per week) who completed a 4-week full-body (FB) and split-body (SB) training protocol of equal volume during the competitive season.

"Both training approaches involved 3 weekly sessions (Monday, Wednesday and Friday) completed between 1600 to 1800 hours. Training involved 8 repetition maximum lifts for selected exercises, performed for 3-6 sets with rest periods of 60-90 seconds between sets and exercises. In the FB protocol, all muscle groups were ex ercised during each of the 3 weekly training sessions, while in the SB protocol only a sub-set of the muscle groups was exercised dur ing each session. The prescribed exercises included; back squats, leg curls, leg press, bench press, bent-over row, pull downs, shoulder press, bicep curls and calf raises. To equate for training volume, the total number of repetitions prescribed each week were identical (i.e. FB training = 21 exercises, 2-3 sets × 8 repetitions; SB training = 13 exercises, 3-6 sets × 8 repetitions). The 2 protocols are commonly used in research and practice and these were incorporated into the weekly schedule of the study population to improve the ecological validity of our findings. A standard warm-up was performed before all training sessions comprising of basic exercises performed with increasing intensities and stretching of the major muscle groups [18], with the athletes self-selecting the inten sity and duration of stretching" (Crewther. 2016).

One repetition maximum (1RM) strength, body composition via skinfold measurements and salivary testosterone (T) and cortisol (C) concentrations were assessed pre and post training.

Figure 1: Rel. changes in strength (1RM in bench presses and squats) and body composition (body mass, body fat (%), fat mass and fat free mass) during the FB and SB training phases (Crewther. 2016).

As you can see in Figure 1, the FB and SB protocols improved upper (7.3% and 7.4%) and lower body 1RM strength (7.4% and 5.4%) to a similar extend. The data in Figure 1 does yet also reveal that the full body workout had a slight edge in terms of its effects on the body fat percentage and total fat mass of the subjects and reduced the latter by 0.5% and 3.6% more than the split training.

Figure 2: Post training period (not immediately post-workout) changes in hormone concentration (Crewther. 2016).

Whether or not this is related to the hormonal changes in Figure 2 is questionable, but it is at least worth mentioning that the testosterone to cotrisol (T/C) increased only (+28%) after the FB training. As the scientists point out,

"slope testing on the individual responses identified positive associations (p ≤ 0.05) between T and C concentrations and absolute 1RM strength in stronger (squat 1RM = 150.5 kg), but not weaker (squat 1RM = 117.4 kg), men" (Crewther. 2016),

a result that does not exactly make it easier to decide whether the hormonal differences were corollary or causative for the differential effect on the body composition of the athletes. What is quite clear, though, is that even within a short window of training, both, FB and SB protocols, can improve strength and body composition in rugby players.

In that, the scientists rightly point out that "[t]he similar strength gains highlight training volume as a key adaptive stimulus" - a result we've encountered in numerous previous studies, as well. What is "news", though is that the program structure (i.e. FB or SB) had a measurable influence on the the body composition and hormonal outcomes, of which the latter were only partly (namely in the strong athletes) related to the strength gains.

Blood flow restriction could also have a place in your periodization plan.

Bottom line: If you are asking me if you should trash your split training routine now and switch to full-body workouts, my answer may surprise you: "No!" Even though, or rather because the study population is significantly more representative of the average SuppVersity reader than in many other studies... what? Well, you will probably train at a significantly higher volume per muscle part, when splitting (in the study this didn't change), the results could thus be completely different for you than they were for the subjects in this volume-equated FB to SB comparison.

Furthermore, we cannot exclude that the subjects benefited from a novelty effects that occurred, because the full body workout was a welcome change from their own regular split routines (we can safely assume that 90% of trainees with more than 2y training experience train according to a body part split). This, in turn, could yet be a reason to answer the previously stated question in the affirmative: "Yes, switch to a full body split, but do it not once and forever, but temporary, as part of a well-planned periodiziation routine." | What do you think? Comment on Facebook!

References:

• Crewther BT, Heke TOL, Keogh JWL. The effects of two equal-volume training protocols upon strength, body composition and salivary hormones in male rugby union players. Biol Sport. 2016;33(2):111–116.

Human Study Provides New Insight into How NSAIDs Speed Up Satellite Cell Recruitment & Muscle Repair in Youngsters

Human Study Provides New Insight into How NSAIDs Speed Up Satellite Cell Recruitment & Muscle Repair in Youngsters

aspirin build muscle COX II ibuprofen NSAID NSAIDs recovery satellite cells

No, I still do not recommend the chronic (ab-)use of NSAIDs, bro.

No, this is not the first study about the effects of NSAIDs on muscle gains I discuss here at www.suppversity.com, but it is certainly one of the more interesting ones. The study which is about to be published in the FASEB Journal was designed to investigate the role of nonsteroidal anti-inflammatory drugs (NSAIDs) in human skeletal muscle regeneration.

As you may remember, previous studies have yielded conflicting evidence with respect to the ability of NSAID to accelerate muscle healing and thus accelerater and ultimately shorten the adaptational process.

Hormesis is why soothing the inflammation is not always good for athletism

Is Vitamin E Good for the Sedentary Slob, Only?

Even Ice-Baths Impair the Adapt. Process

Vit C+E Impair Muscle Gains in Older Men

C+E Useless or Detrimental for Healthy People

Vitamin C and Glucose Management?

Antiox. & Health Benefits Don't Correlate

In the study at hand, the authors did therefored recruit 32 untrained, but healthy young men and randomly assigned them to consume either NSAID [1200 mg/d ibuprofen (IBU)] or placebo (PLA) daily for 2 wk before and 4 wk after an electrical stimulation–induced injury to the leg extensor muscles of one leg.

To assess, whether the ingestion of ibuprofen would, as the scentists suspected alter satellite cell response and time course of regeneration in the experimentally injured skeletal muscle of young healthy men, biopsies were collected from the vastus lateralis muscles before and after stimulation (2.5 h and 2, 7, and 30 d) and were assessed for satellite cells and regeneration by immunohistochemistry and real-time RT-PCR. In conjunction with the likewise measured length of the telomeres, the scientists expected to be able to determine the actual effect of NSAIDs on the post-exercise recovery process.

Figure 1: CD68 and CCL2 are only two markers of the damage/repair process that show a clear phase-shift (meaning earlier elevation = earlier repair) with IBU. Furthermore the ibuprofen "preload" prevented the formation of collage (right) in the muscle after 30 days (Mackey. 2016).

What the researchers found was appears to be a clear advantage... initially: After injury, and compared with PLA, IBU was found to augment the proportion of ActiveNotch1+ satellite cells at 2 d [IBU, 29 +/- 3% vs. PLA, 19 +/- 2% (means +/- SEM)], satellite cell content at 7 d [IBU, 0.16 +/- 0.01 vs. PLA, 0.12 6 0.01 (Pax7+ cells/fiber)], and to expedite muscle repair at 30 d.

The bad news is that the chronic consumption of NSAIDs is nothing a healthy individual should consider - even if it prevents your muscle from collagen depositions (see Figure 1, right); and still, if we could get the benefits observed in the study at hand without the potential long-term side effects of common NSAIDs, they could be a game changer... at least for elderly individuals, in whom the recruitment of satellite cells and thus process of muscle repair appears to be impaired by aging.

The statement that NSAIDs could be particularly beneficial for elderly is more than an unsupported hypothesis. In February, I already wrote about the type-I-specific muscle-building effects of COX-inhibitors | learn more.

So what? No, this is not an endorsment of NSAIDs and I still cannot recommend the chronic ingestion of NSAIDs as muscle builders. I have to admit, though, that I am pretty impressed by the way ibuprofen helped the repair of myofibers in the later stages of regeneration and mediated a more rapid return of satellite cells and muscle extra-cellular matrix (ECM) gene expression levels to baseline values.

As Mackey et al. point out, NSAIDs (in this case IBU) is eventually shifting the entire time course of satellite cell, myofiber - and that without effects on muscle telomere length in human skeletal muscle in vivo. In view of the highly damaging electrostimlation method, it does yet remain to be seen how beneficial effect of NSAID ingestion are when the damate to the muscle is less pronounced and thus in a more physiological range  | Leave a comment and tell me what you think on Facebook!

References:

• Mackey, Abigail L., et al. "Activation of satellite cells and the regeneration of human skeletal muscle are expedited by ingestion of nonsteroidal anti-inflammatory medication." The FASEB Journal (2016): fj-201500198R.

Cardio Can BOOST Your Gains?! Do it Before Weights and be Rewarded With 28% Increased Fiber Size & VO2 Gains

Cardio Can BOOST Your Gains?! Do it Before Weights and be Rewarded With 28% Increased Fiber Size & VO2 Gains

aerobic exercise build muscle build strength cardio concomitant training resistance training VO2 vo2max

It may be important that the subjects cycled, because a recent review of the potential interference of cardio w/ strength training shows that cycling is the least likely to affect your gains (Murach. 2016).

In previous articles at the SuppVersity, I have written about the still ubiquitous concern that cardio training (or aerobic training, in general) could hamper your size and strength gains - a fear that is, unless you overdo it, unwarranted (learn more about HIIT & "regular" cardio training).

Now, a recent study from the Mid Sweden University shows that the opposite could be the case, i.e. that the hypertrophy response to exercise can actually be stimulated by combining resistance training not just with "cardio", but with "cardio" (=continuous cycling) and HIIT - at least if it's done not after, but before resistance training.

Are you looking for muscle builders for the year 2016? Find inspiration in these articles:

Tri- or Multi-Set Training for Body Recomp.?

1, 2, or 5 sets per Exercise? What's "best"?

Pre-Exhaustion Exhausts Your Growth Potential

Full ROM ➯ Full Gains - Form Counts!

Battle the Rope to Get Ripped & Strong

Study Indicates Cut the Volume Make the Gains!

The authors of the study, Zuzanna Kazior, Sarah J. Willis, Marcus Moberg, William Apró, José A. L. Calbet, Hans-Christer Holmberg, andn Eva Blomstrand were (just like you?) unhappy with the contradictory outcomes of existing studies on the effect of endurance exercise on the anabolic response to strength training. Accordingly, they designed a study to "re-investigated this issue, focusing on training effects on indicators of protein synthesis and degradation" (Kazior. 2016).

Figure 1: Overview of the resistance (top) and cardio training (bottom) protocols in the study at hand (Kazior. 2016).

In said study, two groups of previously not regularly trained male subjects performed 7 weeks of resistance exercise alone (R; n = 7) or in combination with preceding endurance exercise, including both continuous and interval cycling (ER; n = 9). You can see the exact protocols in Figure 1, with the resistance training part being on the top and the endurance / HIIT part on the bottom (the number of training sessions in the ER and R group were identical; importantly, the endurance training was performed before the resistance training and included an extra 5-min warm-up + cool-down before and after the E-part.

Did carbohydrates make the difference? Within 20 min after completion of a training session, subjects in the R-group received a protein supplement (Kolozzeum Pure Whey, Stockholm, Sweden), 20 g dissolved in 500 ml of water to enhance muscle recovery. The ER-group were given this same supplement, but with addition of maltodextrin (Fairing Fast Carbs, Järfälla, Sweden) in an amount corresponding to the individual´s calculated energy expenditure during the endurance training - did the maltodextrin make a difference? Based on the results of previous studies, this seems very unlikely. While carbs alone can enhance the protein synthetic response to resistance training (Børsheim. 2004), studies show no benefit of adding it to a sufficient amount of protein that is consumed right after resistance training workouts (Koopmann. 2007). 

Biopsies were taken from the lateral part of m. quadriceps, i.e., the vastus lateralis, both before and after 7 weeks of training. To ensure the results were not messed up, ...

"[t]he subjects were instructed to refrain from training for 2 days prior to the pre-training biopsies and the post-training biopsies were taken approximately 2 to 3 days after the final session in 15 subjects, but in one subject the post-training biopsy was taken 90 hours after the final session. During this period the subjects also refrained from training" (Kazior. 2016).

All data are expressed as means ± SD and were checked for normal distribution before performing parametric statistical analyses. A two-way repeated measures ANOVA (time, group) was applied to evaluate and compare the effect of training in the R and ER groups. When the ANOVA showed a significant main effect or interaction between time and group, Fisher’s LSD post hoc test was applied to identify where the differences occurred. A P-value <0.05 was considered to be statistically significant.

Figure 2: Levels of proteins in the Akt signaling pathway before and after 7 weeks of training. (A) Akt, (B) mTOR and (C) S6K1 in skeletal muscle before (Pre) and after (Post) 7 weeks of strength training only (R) or combined endurance and resistance exercise (ER). Representative immunoblots from two subjects. *P < 0.05 for Post vs. Pre (Kazior. 2016).

While similar increases in leg-press 1 repetition maximum (30%; P<0.05) were observed in both groups, irrespective of the maximal muscle gains - a discrepancy of which the scientists say that it "suggests that the improvement in maximal strength (1RM) observed following our relatively short 7-week period of training is due largely to neuromuscular adaptation" (Kazior. 2016), the scientists observed a striking and highly significant difference between the changes of the subject's maximal oxygen uptake (a marker of cardiovascular fitness) in the two groups. As you may already have expected, the latter was elevated (8%; P<0.05) only in the ER group, while the strength training only group saw no increase in this important fitness marker.

Figure 3: Pre- vs. post changes in fiber are and capillary density in both groups (Kazior. 2016).

And what about the gains? As far as those were concerned, Kazior et al. observed significantly larger increases in the ER training group as well. More specifically, the ER group saw gains in both, the areas of both type I and type II fibers. The R protocol, on the other hand, increased only the area of the type II fibers, which is why it is not exactly surprising that the mean fiber area increased by 28% (P<0.05) in the ER group, whereas no significant increase was observed in the R group - a difference that appears to be in line with the expression of the anabolic proteins Akt and mTOR, which were both enhanced in the ER group, whereas only the level of mTOR was elevated following R training. The scientists further analyses showed that...

"[the t]raining-induced alterations in the levels of both Akt and mTOR [both anabolic] protein were correlated to changes in type I fiber area (r = 0.55–0.61, P<0.05), as well as mean fiber area (r = 0.55–0.61, P<0.05), reflecting the important role played by these proteins in connection with muscle hypertrophy. Both training regimes reduced the level of MAFbx protein (P<0.05) and tended to elevate that of MuRF-1 [both catabolic]" (Kazior. 2016).

In view of these findings, it is only logical that the authors conclude that "the present findings indicate that the larger hypertrophy observed in the ER group is due more to pronounced stimulation of anabolic rather than inhibition of catabolic processes" (Kazio. 2016) - irrespective of the fact that they cannot tell for sure what it was that triggered these practically relevant differences.

Can the increase in IGF1, GH and testosterone as it was observed W/ Cardio first by Rosa et al. (2014) explain the increased size gains?

So what's going on, here? While you may expect that the addition of carbohydrates after the workout in the ER group could have something to do with the increased size gains, the data discussed in the red box shows that this is relatively unlikely (even though it could be the reason why AKT increased only in the ER group).

As far as the reasons for the surprising differences to other studies are concerned, we are thus left with two options: (1) the cardio protocol with steady state + HIIT could be special, or (2) doing cardio before not after strength training could be special. Interestingly enough, I've written about potential anabolic benefits of doing your cardio before weights, before: In a 2014 study, Rosa et al. observed significant increases in the purportedly muscle building hormones GH, IGF1 and testosterone when cardio was done before weights.

Whether it's in fact a pro-anabolic response to reversing the more common order of resistance training > cardio to cardio > resistance training does yet seem questionable - irrespective of the fact that the acute GH response was in fact one out of two parameters of which West et al. have found that it correlates with the actual muscle gains in their seminal 2012 study (discussed here) | Maybe you've got better explanations? If so, leave them in a comment on Facebook!

References:

• Børsheim, Elisabet, et al. "Effect of carbohydrate intake on net muscle protein synthesis during recovery from resistance exercise." Journal of Applied Physiology 96.2 (2004): 674-678.
• Kazior Z, Willis SJ, Moberg M, Apró W, Calbet JAL, Holmberg H-C, et al. "Endurance Exercise Enhances the Effect of Strength Training on Muscle Fiber Size and Protein Expression of Akt and mTOR." PLoS ONE 11.2 (2016) : e0149082. doi:10.1371/journal.pone.0149082
• Koopman, René, et al. "Coingestion of carbohydrate with protein does not further augment postexercise muscle protein synthesis." American Journal of Physiology-Endocrinology and Metabolism 293.3 (2007): E833-E842.
• Murach, Kevin A., and James R. Bagley. "Skeletal Muscle Hypertrophy with Concurrent Exercise Training: Contrary Evidence for an Interference Effect." Sports Medicine (2016): 1-11.
• Rosa C, Vilaça-Alves J, Fernandes HM, Saavedra FJ, Pinto RS, Machado Dos Reis V. "Order effects of combined strength and endurance training on testosterone, cortisol, growth hormone and IGFBP-3 in concurrent-trained men". J Strength Cond Res. (2014): Jul 15 Ahead of Print. 
• West, Daniel WD, and Stuart M. Phillips. "Associations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training." European journal of applied physiology 112.7 (2012): 2693-2702.