"HIIT-ing it After Arm Workouts Will Ruin Your Gains", Study Says and Confuses Statistical and Practical Significance

"HIIT-ing it After Arm Workouts Will Ruin Your Gains", Study Says and Confuses Statistical and Practical Significance

arms build muscle build strength cardio concurrent concurrent training exercise order HIIT strength training

Does this look as if sprinting would impair muscular development of arms or any other muscle? I mean, come on - look at the average sprinter: Many gymrats dream of the arms and overall muscular physique they have; no wonder that the data from the full-text shows a different picture than the abstract would suggest.

I have repeatedly written about combining strength and classic endurance training. With endurance first, endurance last and even endurance in-between the studies yielded often very different results in terms of what would be the optimal way to combine both. With a few exceptions in which resistance training was combined with crazy endurance training sessions, however, I've yet never written about nor seen compelling evidence for the often-heard claim that "cardio ruins your gains".

For HIIT, i.e. high-intensity interval training, a recent study from the Nippon Sport Science University does now claim, though, that my that combining HIIT and weight training may be a very bad idea, ... an idea that may in fact, just as the broscientific nightmare suggests "ruin your gains, bro!" Upon closer scrutiny, however, things appear less unambiguous than the abstract would have it...

You can learn more about the optimal exercise order at the SuppVersity

Before, After or In-Between?

Exercise Order and Leptin Levels

Cardio First for Anabolism?

Large Muscle Groups First?

Combine Cardio & Strength, Right

Cardio or Weights First? What the...

The purpose of the study was to examine whether or not lower limb sprint interval training following arm resistance training influences training response of arm muscle strength and hypertrophy. Or in short: Will doing HIIT sprints immediately after an arm workout ruin the strength and strength gains you've primed before? 

Figure 1: According to the study, you better don't do HIIT sprint training after an intense arm workout if you don't want to ruin the strength and size gains you "primed" with curls and co (photo from Kikuchi. 2015)

The subjects, twenty previously only lightly trained men, were divided into resistance a training group (RT, n=6) and concurrent training group (CT, n=6).

• The RT program was designed to induce muscular hypertrophy (3 sets x 10 repetitions (reps) at 80% 1 repetition maximum [1RM] of arm curl exercise), and was performed in an 8-week training schedule carried out 3 times per week on nonconsecutive days. 
• Subjects assigned to the CT group performed identical protocols as strength training (ST) and modified sprint interval training (4 sets of 30-s maximal effort, separated in 4m 30-s rest intervals) on the same day. 

The relevant study outcomes the researchers evaluated were the changes in maximal oxygen consumption (VO2max), muscle cross-sectional area (CSA), and 1RM that were measured before and after the 6-week study.

Figure 1: Relative changes in VO2max (conditioning), muscle size (CSA) and strength (1-RM) over 6 wks (Kikuchi. 2015).

As the data in Figure 1 reveals, significant increases in VO2max from pre- to post-test were observed only in the CT group (p=0.010, ES=1.84), but not in the RT group (p= 0.559, ES= 0.35). The rest of the results in Figure 1, however should be kind of surprising to anyone who has read the researchers conclusion that "our data indicate that concurrent lower limb sprint interval training interfere with arm muscle hypertrophy and strength" (Kikuchi. 2015).

No, you are not mistaken. The average muscle size and strength gain in the combined training group was larger. The reason the scientist still claim that their study would show that HIIT impedes strength adaptation is a statistical one. While the changes in the CT group had p-values p > 0.05 and were thus not statistically significant. The (albeit smaller) mean increase in the RT group was significant. Accordingly, the corresponding "effect size" in the RT group is larger than the one in the CT group and thus HIIT training must be bad, right? Well,... I don't think so.

If you take a closer look at the individual muscle  size and strength development, you should notice that being afraid that sprints would ruin your arm development is unwarranted and the statistical significance and effect sizes of the changes practically irrelevant.

Beware of bling faith in abstracts! If you look at my plot of the individual data the scientists luckily published with their full-text, it is yet obvious that this study does not prove and if we are honest, not even really suggest that there practically relevant negative effects of doing HIIT in this workout. If you just read the conclusion to the abstract, which reads "our data indicate that con-current lower limb sprint interval training interfere with arm muscle hypertrophy and strength" (Kiku-chi. 2015), you may be inclined to make unne-cessary changes to your workout that are neither necessary or productive. After all, the objective result of the study is that in some individuals it is possible that the addition of HIIT to an arm workout may have a minor impact on their gains.

In view of the facts that there's (a) one person with a roughly ~41% increase in sleeve sizes in each group and that (b) the average increase in sleeve size would be 23% in the CT and only 21% in the RT group if the two outlayers who lost muscle (one in each group) were excluded, though, I would suggest you ignore this possibility unless you realize that you're making no gains at all with concurrent training. This doesn't falsify the scientists' conclusion, which is based on scientific standard procedure, i.e. look for statistical significant results, use those to make your conclusion, but I felt I needed to write this article to put the theoretically correct interpretation of results of an unquestionably under-powered study into perspective | Comment!

References:

• Kikuchi et al. "The effect of high-intensity interval cycling sprints subsequent to arm-carl exercise on muscle strength and hypertrophy in untrained men: A pilot study." Journal of Strength and Conditioning Research Publish (2015): Ahead of Print | DOI: 10.1519/JSC.0000000000001315

Cardio After Weights! Doing Resistance Before Endurance Training Has More Beneficial Effects on Leptin, Cortisol, Testosterone and Body Composition in Young Men

Cardio After Weights! Doing Resistance Before Endurance Training Has More Beneficial Effects on Leptin, Cortisol, Testosterone and Body Composition in Young Men

build muscle cardio cortisol endurance endurance training exercise order leptin lose fat resistance training testosterone weight training weights

I can almost guarantee that the results of this study are not sex-specific. Ladies, pick up the weights fater you hit the treadmill, stairmaster, elliptical or other torture instrument you like to use!

It has been a while since the last study on exercise order (cardio or weights first) has been published. Now, scientists from the University of Kurdistan have conducted another study to investigate the effects of intrasession sequencing of concurrent resistance and endurance training on the serum leptin, testosterone, cortisol responses and body composition in obese men.

And don't worry, we are not talking about useless acute-phase data that shows no correlation with either strength or muscle gains, or fat loss (West. 2012). Sheikholeslami-Vatani and colleagues conducted an eight-week study on thirty obese young male students without continuous exercise history (age: 23.2±1.4 year, BMI: 31.8±1.6 kg/m²).

You can learn more about the optimal exercise order at the SuppVersity

Before, After or In-Between?

Exercise Order and Leptin Levels

Cardio First for Anabolism?

Large Muscle Groups First?

Combine Cardio & Strength, Right

Exercise Order Reloaded

The subjects were randomly divided into three groups: concurrent resistance-endurance (CRE, n = 10) group, concurrent endurance-resistance (CER, n = 10) group and control (C, n = 10) group (no training program). The concurrent training groups (CER and CRE) trained three times a week on alternate days for 8 weeks. The training itself consisted of which consisted of ...

"running with 70—75% of maximal heart rate (HRmax) for 10 minutes which gradually increased to 80% HRmax for 21.5 minutes [plus] resistance training consisted of 3 sets of 8 repetitions at 80% of 1 repetition maximum (1RM) in 5 resistance exercises (leg extensions, lying leg curl, triceps pushdown, bench press and lateral pull down)" (Sheikholeslami-Vatani. 2015). 

In-between the endurance and resistance (or vice versa) training parts of the workouts, the subjects rested for 5 minutes. Blood sampling and skin-fold measurements to asses the body composition was conducted 48 hours before the start of the course and again 48 hours after the last training session (learn why waiting longer for the body comp test may have been better, but no study does that).

Figure 1: Relative changes in hormone levels (left) and absolute and relative changes in body fat fat free mass and body fat % (right) after 8 weeks of doing nothing (C) or doing cardio (CER) or weights (CRE) first (Sheikholeslami-Vatani. 2015).

I've plotted the most important results in Figure 1a & b. So, let's take a look: The first thing that everyone should see is that both workout regimen had relevant health and physique effects:

• 

  Similar gains w/ weights vs. cardio first in trained men | more.

  normalization of leptin levels (health)
• slight increases in testosterone (health)
• increases in cortisol (which are benign | learn why)
• significant reductions in body fat (health + physique)
• increases in fat free mass (health and physique)

In that, the resistance training first (CER) group came off slightly better in all tested study outcomes. Statistical significant inter-group differences, however, were observed only in comparison to the control group. In view of the fact that the body fat (total and %) improvement reached statistical significance compared to control only in the endurance first, group, yet not in the strength first group, one may still argue that the difference between cardio first (CER) and weights first (CRE) was "almost significant" ;-)

Weights or Cardio? What's the Best Visceral Fat Burner + How Often, Long and Intense Do You Have to Train | Learn more!

So, weights first is the way to go? Well, I assume I should write that doing both on separate days and thus doing having 5-6 workout days per week may have even more pronounced effects on the body composition of obese young men. In the end, though, I have no evidence to prove that doing the same amount of cardio on a separate day would actually have yielded greater improvements in body composition. Against that background and in view of the fact that three workouts per week is everything that fits into the busy schedules of the average trainee, we are left with the confirmation that (a) doing (intense) cardio and weights in one session feasible and effective when the goal are health and physique improvements and that (b) if you or your clients combine both, you better start with the weights, not the cardio part | Comment!

References:

• Sheikholeslami-Vatani, D., et al. "The effect of concurrent training order on hormonal responses and body composition in obese men." Science & Sports (2015).
• 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.