Tuesday, July 5, 2016

When "No Load Training" Builds Muscle and Classic Biceps Curls Diminish Your Triceps Size, Science Must be Involved

Do not misunderstand the results of the study at hand. It does not "proof that you don't have to use weights to make size gains" and it does not even suggest that "training without load works as effectively as training with loads for every muscle".
I suspect you will remember that I have previously written about the potential muscle building effects of posing. Now, the isometric contractions you perform when you "pose", are not exactly the same, but at least related to the "maximal contractions through a full range of motion" Counts et al. investigated in their latest study. Accordingly, it doesn't seem to be totally far-fetched to assume that (1) increases in muscle size would be similar with this type of NO LOAD compared to HIGH LOAD training and that (2) HIGH LOAD training would still result in a greater strength increases compared to NO LOAD due to the principle of specificity.

To elucidate whether these hypotheses are accurate, Counts et al. recruited fifteen (6 men, 9 women) participants for a 6-week study (see Figure 1) ... untrained subjects.
It could be a good idea to use NO LOAD training as part of your periodization schemes.

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Untrained? I know what you're thinking, but you got to start somewhere and to measure significant muscle gains in only 6 weeks, your subjects almost have to be untrained; even if this means that it is neither necessarily nor likely possible to transfer your results to trained individuals. It is thus well possible, that the NO LOAD conditions, the authors describe as follows, ...
"[t]he NO LOAD training condition is defined as voluntarily maximally contracting the muscle through the full range of motion without the use of an external load. During each NO LOAD training session, surface electromyography (EMG) electrodes were applied to the biceps to provide feedback to the participant and to help encourage greater activation during each repetition. The participants completed 4 sets of 20 repetitions with 30 seconds of rest between sets. This protocol was based off of pilot work performed in our laboratory which suggested that 4 sets of 20 repetitions should result in increases in both fatigue and muscle activation" (Counts. 2016).
... will have smaller or even no effect at all on the muscle size of already trained individuals - and that would obviously be much in contrast to the tried-and-proven HIGH LOAD training in which the authors completed 4 sets of 8–12 repetitions with 90 s of rest between sets at 70% of their 1RM (weight was increased if more than 12 reps could be done).
Figure 1: Study design outline. 1RM – one repetition maximum (Counts. 2016).
But enough of the "could"s and "might"s. Let's take a look at what we can says for sure: In the study at hand, where both conditions exercised to a metronome at a cadence of 1.5 s for the concentric and eccentric portion of the lift, totaling a 3 s contraction, the subjects were assigned to the NO or HIGH load condition according to a counterbalanced design and the results were quite intriguing:
  • Contracting muscle through a full range of motion with no external load increases muscle size similar to high load training.
  • High load training produced larger increases in 1RM strength & muscle endurance compared to contracting with no external load.
  • Muscle growth can occur independent of the external load provided sufficient tension is produced by the muscle.
  • Muscle strength is proportional to the load being used and the modality of exercise being performed (specificity)
More specifically, the study results show that anterior muscle thickness increased similarly from Pre to Post, with no differences between conditions for the 50% [Pre: 2.7 (0.8) vs. Post: 2.9 (0.7)], 60% [Pre: 2.9 (0.7) vs. Post: 3.1 (0.7)] or 70% [Pre: 3.2 (0.7) vs. Post: 3.5 (0.7)] sites, that there is a significant condition × time interaction for one repetition maximum (p = 0.017), with HIGH LOAD (+2.3 kg) increasing it more than the NO LOAD condition (+1 kg) and thus that it is, as Counts et al. write "generally possible to make gains [at least in untrained individuals] across a vast range of external loads and muscle actions" - even independent of external load "provided there are enough muscle fibers undergoing mechanotransduction" (Counts. 2016).
Figure 2: Mean muscle thickness from pre to post training at 50%,60% and 70% sites of the anterior (biceps) & posterior (triceps) upper arm (left) and individual differences in anterior muscle thickness (right | Counts. 2016).
Before you drop the weights altogether, though, you should know that there are a few other limitations of the study (next to the previously hinted at lack of training experience in the subjects) the scientists discuss: They range from the lack of quantitative data on the volume of work completed in the NO LOAD condition (workload is distance times weight - with no weight, you cannot calculate it), of which the scientists say that it "may explain some of the variability in the growth response following NO LOAD training" to the choice of tests which are "more specific to the HIGH LOAD condition and less specific to the NO LOAD condition[. Consequently] it stands to reason that NO LOAD training's effect on strength may be underestimated" (Counts. 2016).

Eventually, the results of the study at hand, as intriguing as they may be, must thus be considered preliminary evidence in support of the mechanotransduction theory of muscle building and its implications, namely that no external load is necessary to stimulate the transcription factors that will eventually initiate the adaptive response to "no-weight lifting" (see Figure below)
Overview of the main events during signal transduction and gene regulation leading to muscle hypertrophy (my orange emphasis in a figure from Rennie, et al. 2004)
So, yes further research is war-ranted to evaluate whether training w/out load could make sense for trained individuals as well.  I have to admit, though, that the existing evidence on the underlying mechanisms of muscle growth supports the notion that training for size does not necessarily involve high weights or muscle damage. After all, the hypertrophy driving trans-criptional factors (see Figure on the right) can be induced by Ca2+ increa-ses, stretch and hypoxia, which can all be achieved in the absence of high loads or sign. muscle damage (Rennie. 2004)... and still, I have my doubts about the effects on trained individuals.

What? Oh, yes... the hint at the reduced posterior muscle (=tripecs) size from the headline. I almost forgot that. Well, the scientists were probably not less surprised than you were when you looked at Figure 2 and realized that the tried and proven "HIGH LOAD condition decreased posterior upper arm muscle thickness following 6 weeks of bicep curl training" (Counts. 2016). Just like me Counts et al. are "not aware of any studies that investigated HIGH LOAD resistance training that targeted only the biceps and measured muscle size of both the biceps and triceps"; and in contrast to what I previously suggested, this cannot be a methodological artifice, because the ultrasound measures the scientists used could distinguish between muscle and fat. What exactly the reason for the ostensible 'atrophy' of the triceps muscle is, may thus still be called a 'mystery' - one that needs to be addressed in future studies, though... (thx Jeremy for spotting this mistake) | What do you think, any ideas on the mechanism? Comment on Facebook!
  • Counts, Brittany R., et al. "The acute and chronic effects of “NO LOAD” resistance training." Physiology & Behavior (2016).
  • Rennie, Michael J., et al. "Control of the size of the human muscle mass." Annu. Rev. Physiol. 66 (2004): 799-828.