Your Post-Workout Testosterone Levels Can Predict Your Gains - Study Takes Novel Approach to the T ↔ Muscle Link

Your Post-Workout Testosterone Levels Can Predict Your Gains - Study Takes Novel Approach to the T ↔ Muscle Link

build muscle gains gainz GH hormones IGF-1 insulin muscle gains testosterone

GainZ - Are they all about T and we just didn't do the right statistical tests in previous studies to realize that?

Only recently one of the longstanding "truths" of protein anabolism has been busted (learn why the acute muscle protein synthesis response matters more than prev. thought). And now, a new paper in the Journal of Strength and Conditioning Research (Mangine. 2016), appears to suggest that the lack of effect of exercise induced hormone elevations may have been misunderstood, too.

In the conclusion of their study, Mangine et al. point out that the previously used "[t]raditional statistical measures do not adequately assess the relationships between multiple variables that exist across time" (Mangine. 2016).

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In order to overcome this problem, their study used what the scientists call a "unique method for analyzing these types of relationships without the need for transforming data"; and - first things first - their the PLS-SEM analysis (details below) shows: "baseline muscle size and the hormonal response to resistance exercise are related to muscle hypertrophy following 8 wks of training  (Mangine. 2016).

Figure 1: The scientists ,odel for the relationship between changes in muscle size and the endocrine response to resistance exercise predicts influence of all hormones on muscle size and vice versa(!); RF_CSA = Rectus femoris cross-sectional area; RF_MT = Rectus femoris muscle thickness; VL_CSA = Vastus lateralis cross-sectional area; VL_MT = Vastus lateralis muscle thickness; WK1 = Week 1; WK8 = Week 8 (Mangine. 2016).

Moreover, the data from the Kennesaw State University, the University of Central Florida and the College of New Years appears to suggest that the often derided exercise-induced post-workout (PWO) increases in testosterone concentrations may be the most important agent in the hormone quintet of testosterone, cortisol, growth hormone, IGF-1, and insulin that is going to react to every intense resistance training study.

Figure 2: Sign. associations between PWO hormone levels and lean mass, as well as fiber size increases (West. 2012).

That's surprising in two ways: (A) the majority of previous studies refuted the existence of a practically relevant link between the amount of muscle you will gain and the change in hormone levels, altogether. And (B) you will remember that my hitherto favorite study on the "[a]sociations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training" by West and Phillips (2012) showed in a large cohort that - if there is any link between the PWO hormone response to resistance training and the changes in muscle size it would be a link to growth hormone (GH) and cortisol (see Figure 2).

Free testosterone (upper line) and cortisol (lower line) levels before and after exhaustive endurance exercise in trained young men (Anderson. 2016).

Excess cardio cannot, it will ruin your testosterone levels and (surprise) 24h post also your cortisol levels: The data in the figure on the left hand side was recorded in a recent study by Anderson et al. (2016) who observed that the full recovery of free testosterone and cortisol after an exhaustive endurance exercise session (prolonged exercise run on the treadmill until volitional fatigue, running at 100 % of ventilatory threshold (VT), within 3 % - 75 minutes) will take 48h - even in endurance trained fit, young men such as the 12 subjects (VO2max 66.3±4.8 ml/kg/min, age 22.8 ± 3.1 years, body fat 11.0 ± 1.4 %, training 7.1y) Anderson et al recruited.

That's obviously significantly different from what we see in the Magine study, at hand, where the likewise previously trained subjects completed at least 28 resistance training sessions (~90%) of an 8-wk resistance-training program (4 sessions/wk) that included six upper- and lower-body exercises during each session, under supervision of certified strength & conditioning specialists.

With the inclusion of potential influence of the initial muscle mass on the hormonal response to exercise Magine's study does now suggest what many trainees still believed, anyways: "When it comes to making gainz, the testosterone response to workouts counts." Furthermore, the scientists argue that the reason studies like McCall et al. (1999), Ahtianinen et al. (2003), and Walker et al. (2015), which used Pearson’s product moment correlation coefficients or Spearman’s rank correlation coefficients (Walker. 2014) were conflicting and not really reliable, because...

"significant amount of information [that] is lost when using either of these statistical procedures for assessing the relationships between concepts that exist across time (i.e. hypertrophy, multiple endocrine responses) because the statistics can only assess the relationship between two sets of values" (Mangine. 2016). 

With their approach, on the other hand, Mangine et al. (2016) transformed the correlation between hypertrophy and the endocrine response from baseline and post-testing into a single value (i.e. change score, average score). The method to do this is called "partial least squares structural equation modeling" (PLS-SEM) and it allows estimating complex cause-effect relationship models with latent variables. Since it is a component-based estimation approach, it differs from the covariance-based structural equation modeling you'd usually expect to be used and constitutes, as the scientists summarize

"[...] a variance based procedure that utilizes bootstrapping to statistically assess the relationships between multiple latent variables that are developed from several collected indicator variables [which has] been used to assess relationships within the biomedical sciences [already... even though] it has not yet been used to assess the relationships between the post-exercise endocrine response and muscle hypertrophy" (Mangine. 2016).

For it to work, the authors obviously have to assume that "the related variables were collected without systematic or random error" in their experiment that included pre-tests (PRE) of measures of muscle size (thickness and cross-sectional area) of the vastus lateralis and rectus femoris in 26 resistance-trained men who were randomly selected to complete a high-volume (VOL, n=13, 10–12RM, 1-min rest) or high-intensity (INT, n = 13, 3–5RM, 3-min rest) resistance training program while following a food-log controlled diet that was supplemented with a standardized supplement containing ~235 mL of chocolate milk (170 calories; 2.5g Fat; 29g Carbohydrate; 9g protein) or Lactaid® (150 calories; 2.5g Fat; 24g Carbohydrate; 8g protein) to each participant immediately following each workout.

A pre- vs post-workout salivary testosterone test could hold the clue to the perfect workout | more

Another argument that "testosterone may count" comes from a previously discussed, but in my humble opinion largely overlooked study by Beaven et al. (2008) whose study into the correlation between the individual testosterone response to a certain workout style and the subsequent gains subjects in a randomized cross-over design study made also suggests that "testosterone counts". Sounds intruiging? I know, but the corresponding SuppVersityarticle from 2013 went almost as unrecognized as the original paper that was published 5 years before in the Journal of Strength and Conditioning Research - the same journal in which Mangine et al. have now published the results of their study.

Blood samples were collected at baseline, immediately post-exercise, 30-min, and 60-min post-exercise during weeks 1 (WK1) and 8 (WK8) of training and testosterone, growth hormone [22 kD], insulin-like growth factor-1, cortisol, and insulin levels were evaluated using area-under-the-curve (AUC) analyses of the blood values, based on which the scientists were able to identify the relationships between muscle size (PRE), AUC values (WK1 + WK8) for each hormone, and muscle size (POST) "using a consistent PLS-SEM algorithm and tested for statistical significance (p<0.05) using a 1000 samples consistent bootstrapping analysis" (Mangine. 2016).

Figure 3: Actually significant was only the link between the effect of the muscle mass before the study and the testosterone response and the testosterone response on the muscle mass after the 8-wk study (Mangine. 2016).

The model the scientists developed was capable of explaining 73.4% (p<0.001) of variance in muscle size at POST and revealed "[s]ignificant pathways between testosterone and muscle size PRE (p=0.043) and muscle size at POST (p=0.032) were observed.

Table 1: In contrast to what you may have expected, there was no sign difference in the way the hormones effected the outcomes of the 8-wk resistance training study between the high intensity and volume arm (Magine. 2016).

And while the ability to explain muscle size at POST improved when the model was analyzed by group (INT: VOL: p<0.001), the data in Table 1 goes to show you that the researchers found no group differences between the intense low volume and the moderate intensity high volume training. This in turn suggests that the link between muscle size and post-exercise increases in hormone levels - especially the effects on testosterone - are universal and do not dependent on the training type (volume vs. high intensity), as previous studies that argued in favor of volume training based on its more pronounced effects on the hormone response to exercise suggested.

In view of the conflicting evidence and hitherto relatively conclusive evidence that endogenous T & co elevations do not matter, I would not begin to train "for testosterone elevations", now... you may after all still be barking up the wrong tree. Correlations and links are after all no causations | learn more

Bottom line: I would like to point out that the study at hand does not provide sufficiently reliable evidence to say that Mangine, et al. had 'proven that the post-workout testosterone increase had a mechanistic effect on your muscle gains'. What it does show, however, is, just as the scientists say, that "[e]xercise-induced testosterone elevations, independent of the training programs used in this study, appear to be related to muscle growth" (Magine. 2016, my emphasis in the quote).

This is in contrast to previous studies, where the pre-tfiraining correlation between muscle mass and thus testosterone levels had not been accounted for. The scientists' partial least squares regression structural equation modeling (PLS-SEM), however, is eventually just "statistical shenanigan". Therefore, its impressive explanatory power of 73.4% of the variance in muscle size following 8 wks of resistance training is a neat figure, but no proof of a mechanistic link.

Furthermore, one has to be careful to falsely single out testosterone among the five hormones that were assessed. After all, restricting the model to T, which was the only significant hormonal correlate of muscle gains, reduced the explanatory power of the model by only 30.8%. This leaves the rest of the hormones with an explanatory power of 42.6% (all statistics, obviously ;-). To say that GH, IGF-1, insulin and cortisol had 'no say' in skeletal muscle hypertrophy is thus just as unwarranted as the previously hinted at (false) conclusion that the study at hand would provide the long-sought definitive evidence of the muscle building effects of exercise-induced, natural testosterone surges, i.e. the temporary elevation of T-levels after a workout | Comment!

References:

• Ahtiainen, Juha P., et al. "Muscle hypertrophy, hormonal adaptations and strength development during strength training in strength-trained and untrained men." European journal of applied physiology 89.6 (2003): 555-563.
• Beaven CM, Cook CJ, Gill ND. Significant strength gains observed in rugby players after specific resistance exercise protocols based on individual salivary testosterone responses. J Strength Cond Res. 2008 Mar;22(2):419-25.
• Mangine, Gerald T., et al. "Exercise-Induced Hormone Elevations Are Related To Muscle Growth." The Journal of Strength & Conditioning Research (2016).
• McCall, Gary E., et al. "Acute and chronic hormonal responses to resistance training designed to promote muscle hypertrophy." Canadian Journal of Applied Physiology 24.1 (1999): 96-107.
• Walker, Simon, et al. "Effects of prolonged hypertrophic resistance training on acute endocrine responses in young and older men." Journal of Aging & Physical Activity 23.2 (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.

Hormonal Response to Exercise, Revisited: A Consequence, not a Determinant of Your Mood, Effort & Performance

Hormonal Response to Exercise, Revisited: A Consequence, not a Determinant of Your Mood, Effort & Performance

build muscle DHT female GH growth hormone HIIT hormones performance resistance training testosterone women women strength

Studies in men suggest no effect of the hormonal response on training outcome - What about women? A news study provides insights that may be relevant for both female and male gymrats.

It has been a few years that I last wrote about the "hormonal ghost". Back in the day, Stuart M. Phillips published an excellent paper that debunked the myth of a mechanistic link of post-exercise increases in testosterone, growth hormone, IGF-1 and co., on the one hand, and exercise-induced strength and size gains, on the other hand. And for those for whom Phillip's review of the literature was not convincing enough, Daniel WD West's 2012, which showed none of the expected associations between exercise-induced hormone profiles (first and foremost higher post-workout testosterone levels) and the rate or significance of muscle strength and size gains in a large cohort of young men after weight training, should have been evidence enough to stop believing in "hormonal ghosts", but alas... you will probably know that "training for testosterone increases" is still en vogue.

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That's stupid stubbornness, nothing else, right? Well, even though I don't believe in ghosts, I have to admit that a closer look at West's data will have you reject the hypothesis that the post-workout testosterone response would augment size gains, it does yet also show other hormonal changes do correlate with the changes in the study's subjects' lean mass (Figure 1, left) as well as type I (middle) and type II fiber size increases (Figure 1, middle & right).

Figure 1: Sign. associations between PWO hormone levels and lean mass, as well as fiber size increases (West. 2012).

As you can see in Figure 1, this was the case for the cortisol response and the lean mass gains and the growth hormone (GH) response and the increases in type I ('endurance') and type II ('strength') fiber size. Even though I don't believe that more than 1% of the gymrats world-wide who still believe that maximizing the post-workout "anabolic response" would help them to maximize their gains even know about these results, you could argue that these correlations fuel their beliefs - even if that's paradoxical, because - in bro-scientific terms - you'd have to maximize the catabolic response, i.e. the increase in cortisol (which could by the way simply be a measure of training intensity) in order to maximize the overall gains in muscle size, but alas...

Figure 2: Changes in anabolic and catabolic hormones in response to AM and PM HIIT and RT training (Toon. 2015).

In a series of experiments Rebecca Toone conducted for her thesis, she re-addressed the issue of the acute hormonal effects on performance with female study participants (yes, a long-term study was not part of her thesis, but I promise, the results are still noteworthy).

Higher sprint cadence (RPM) during HIIT, higher increase in DHT in the female study participants (Toon. 2015).

DHT another acute phase reactant? Even though the overall results of the study suggest that increased pre- vs. post workout changes in DHT as Toone observed the with higher RPM-numbers during HIIT sprints are not the reason, but rather the consequences of training at higher intensities, it is worth mentioning that this is the first study to observe the existence of an association between DHT and HIIT performance in women and that the results are in line with the results of previous research suggesting that DHT, not its precursor, testosterone, has a direct influence on skeletal muscle force production in vitro. 

After some preliminary testing, Toone began with another of the infamous "AM vs. PM" workout studies in which she unsurprisingly confirmed that...

"[...] it could be beneficial to perform resistance training in the afternoon preceded by interval exercise in the morning in order to stimulate a hormonal milieu that may be more conducive to stimulating muscle protein turnover" (Toon. 2015). 

If you scrutinize the data in Figure 2, you can see that this hypothesis is warranted, because of the differential response of the anabolic hormones, testosterone and IGF-1, and the stress / catabolic hormones, cortisol and prolactin, she observed in her young female subjects. Against that background it is quite interesting that Toone's last and most important experiment, in which she investigating the potential acute effects of hormones on performance, failed to demonstrate a direct correlation between changes in testosterone or other "anabolic" hormones and her subjects' performance.

"The trial consisted of a 20 min effort at a target power of 80% of the average power obtained during the maximal 20 min TT, followed by a 5 min break, before completion of a bout of repeated sprint interval cycle exercise consisting of 10 x 30 s sprinting, with 90 s recovery. The session was self-paced with real-time numerical feedback provided on elapsed time, cadence and power. Participants were given verbal encouragement at specific time-points throughout the trial. The same protocol was repeated for the second main trial one week later. Participants were permitted to drink water ad libitum throughout the trials. Trials were completed in a group setting as a group of six and a group of eight. A trial timeline schematic is displayed [in Figure 3]" (Toon. 2015).

Instead, the results of the previously described exercise test point towards affective variables, i.e. mood and effort, as the factors that mediate any link between hormonal changes and performance markers during an acute bout of high intensity cycling.

Figure 3: Design of the last and most important experiment of the study (Toone. 2015).

And guess what, the effort Toone's subjects invested into their workouts was not just a predictor of their performance, it was also positively associated with the percent change in testosterone concentration from post-sprint 4 to post-exercise (r = 0.449; P < 0.01).

Note: We are till talking about associations and correlations. That one of these, e.g. the one between the effort we put into our workouts and the preformance and hormonal response exists because of a causal link is thus in view of the results of the study at hand logical, but still hypothetical. As I am about to point out in the bottom line, future studies will have to investigate that - even though I have to admit that it will be difficult to develop an effective design for these studies.

In conjunction with the subjects' affect, which was inversely correlated with the rate of perceived exertion, which in turn showed positive correlations with cortisol, the results highlight a previously overlooked role of effort and affect when it comes to both, exercise performance and its effect on certain hormones.

Figure 4: The hormonal response is rather the consequence than the trigger of acute performance.

Or as Toone has it in her interpretation of these somewhat surprising results: The acute short-term effects of hormone concentrations on performance may be more related to mood and behaviour" than the actual type / time of exercise in the context of her study.

What does that mean? Practically speaking this would confirm what I have said about the initially cited West study in several previous SuppVersity articles. In said study, cortisol probably has no mechanistic effect on muscle size. Rather than that, the increase in cortisol could serve as a measure of how much effort the subjects put into their workouts; and this, in turn, determined their muscle gains (more effort = bigger growth stimulus = greater gains).

The meager and transient increase in testosterone after your workouts has none of the muscle building and fat shedding effects of exogenous testosterone. The latter however, can turn back the time and an aging pouch into a true best-ager | learn more.

In the study at hand, the situation appears to be similar. Mood and effort determine performance and hormonal response of the female study participants. Accordingly, there may be associations between exercise performance and certain hormones, but those are of corollary, not causative nature. In the absence of an additional experiment that would investigate the correlations and associations between mood, effort, RPE, hormones and the exercise-induced adaptation in the long run, we can still only speculate that making the workouts more fun and stimulating maximal effort would promote both, the adaptive response and the hormonal response and thus confirm that mood and effort are in fact the most relevant determinants of the outcome of your workouts | Comment!

References:

• Phillips, Stuart M. "Strength and hypertrophy with resistance training: chasing a hormonal ghost." European journal of applied physiology 112.5 (2012): 1981-1983.
• Toone, Rebecca. Assessing the Hormone Response to High Intensity Exercise and Identifying Associations with Performance. Diss. University of Bath, 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.