Full ROM = More Growth, More Strength, More Structural Changes & More Sustainable Gains & Fat Loss - Insights from Realistic 8 Weeks Leg Training + 4 Weeks Detraining

"That's not 90°, yet. Do deeper!"

I guess you will be remembering last week's post on the superior growth effects of full vs. partial squats, hah? Now, the results of the Bloomquist study certainly raise the question, whether the same or similar effects must be observe with different exercises or even different body parts, as well. After all, it would be bro-science at its best to generalize the result "full squat = full quad development" to "partial ROM  = partial strength and hypertrophy response" without the least hint of evidence that this hypothesis is more than just the "proposition or principle put forth or stated (without any reference to its correspondence with fact) merely as a basis for reasoning or argument" ("hypothesis, n.". OED) the word "hypothesis" implies - right?

The good news is that it appears as someone has heard my lamentations about the scarcity of respective research, or - what's in this case more probably - feel the same about the necessity to generate data that would be necessary to base our workout protocols on more than just "hearsay", hypothesis and "N=1 experiences" and a single study.

Ok, enough kiddin' around let's get to the facts

Table 1: McMahon's interpretation of an "ecologically valid resistance training program"; * denotes static holds for time in s, DL = double, SL = single legged (McMahon. 2013)

Despite the fact that the study I tried to make tempting to you in the introduction is again build around a leg training routine, it has two major advantages compared to the Bloomquist study: (1) The participants performed a complex, multi-exercise leg-training protocol, (2) the study used the vastus lateralis as yardstick for the size gains, (3) the effect of full vs. short ROM (range of motion) on strength, muscle structure and body fat were also measured and (4) the study had an active training part (8 weeks on the protocol outlined in table 1) and - and this is pretty unique - a subsequent 4-week follow-up in which the subjects did not train (detraining) that allow us to determine whether the persistency of the gains will also depend on whether you achieved the training with a limited 50° vs. a "full" 90° specific angle of knee flexion (McMahon. 2013).

With the the specified angle being defined as the "position at which the training load is held isometrically for two seconds",

• the 50° regimen involved a shorter ROM (SR) in the dynamic phase of the exercise and thus a shorter ‘average muscle length’, whereas
• the 90° regimen involved a longer ROM (LR) in the dynamic phase of the exercise and thus a longer ‘average muscle length’
  *you will learn more about the importance of muscle lengthening later this week, so stay tuned!

McMahon & Onambélé-Pearson hypothesized that the group training "at longer muscle length" (90°) would undergo a greater amount of skeletal muscle hypertrophy and concomittant strength development and that these differences would be "due to increased physiological stress and stretch on sarcomeres compared to the group training at 50°" (McMahon. 2013) and that these effects would be evident even during / after the deloading phase.

Figure 1: Cross sectional area (CSA) of the vastus lateralis measured at 25, 50 and 75% of the femur length for the full range (LR), partial range (SR) and a non-exercised control group (McMahon. 2013)

If we take a peak at changes in muscle cross sectional area (CSA) in figure 1 this hypothesis appears to be roughly accurate. There are however significant differences in the growth response the scientists measured at 25%, 50% and 75% of total femur length (VL25-75), with a statistically non significant advantage for the high(er) load, short-ROM approach (the higher load is a natural consequence of the RM prescription) and a highly significant advantage for the low(er) load, full-ROM approach, when it comes to that part of the muscle you want to shine, as it contributes to that massive "tear-drop look".

"CSA increased significantly (p<0.05) relative to baseline following training at all sites in both training groups. The significant training effect remained during the whole detraining period in both training groups at both 50% and 75%, but was not evident at 25% of femur length after week 10. There was a trend for LR to exhibit greater relative gains in a CSA compared to SR at all sites, which was significant at week 8 at 75% of femur length. It was found that there was not only a main training effect (p<0.05) but a main group effect after week 8 (p<0.05) with LR exhibiting a 59±15% compared to SR showing 16±10% increment in VL CSA." (McMohan. 2013)

To the surprise of the researchers, the "following the first two weeks of detraining the group effect was no longer evident (p=0.07)" (McMohan. 2012). In the end, the existing advantage of training over the full-ROM, as pronounced as it may be at the CSA75 site, is thus short lived in this group of previously non-resistance-traind 26 volunteers (14 males and 12 females). The fasicle length, which increased by
23±5%, 19±4%, 16±4% at weeks 8, 10 and 12 in the LR and by only 10±2%, 6±2% and 2±2% in the SR group (data not shown), on the other hand, were persistent - yet only in the full range (LR) group.

"And body fat? What about the body fat"

Crossfit doesn't fit well with everyone. In  fact, you have to be pretty fit already if you intend to benefit - specifically if you don't have someone who tailors the workouts to your specific needs. If you the shed 8% of your already low 16% body fat in 10 weeks workout routine I wrote about in February, chance is you'll just get injured or burned out (learn more)

The local reduction in subcutaneous fat that was likewise assessed based on the ultra-sound images the scientists used to evaluate the structural changes and CSA increases did not show significant group effects at 25%. The relative changes of 5% in the partial (SR) and 22% at the 50% measuring mark in the full ROM (LR) groups, clearly suggest that "going all the way" would still be the way to go if you don't want to look hypermuscular, but lean (ladies?). The latter is particularly true in view of the facts that the ...

"[...] main effect of group remained during weeks 10 and 12, as SR regressed toward baseline by week 12, whereas LR still possessed significant losses at this phase (-10±6%)" (McMahon. 2013)

and that there was a similar trend seen at 75% where a main effect of both group and training existed at week 8 (p<0.05) - even if the latter vanished in the course of the 4-week detraining period 7±3% SL and 9±1% LR).

Regional growth and angle-specific strength gains

Contrary to all previously reported values, which were - if they were group specific at all - regionally different, the changes in strength showed - as you would expect it - an angular specificity. While both groups did increase their strength, there were more than just minute differences between the partial (SR) an the full ROM (LR) groups:

• at the end-ranges, the maximal volunary contractive force increased 5±10 for SR at 50° and 30±5% for LR at 90°, respectively
• there was evidence of angular specificity of training in both groups with SR significantly (p>0.05) increasing MVCs at 50, 60, 65, and 70° , only, wheres the participants in the LR increased their MVCs values over the entire angular range.

What's remarkable, yet non necessarily beneficial, is the fact that the angle of peak torque which had been 75° at the beginning of the training intervention decreased to 70° within 8 weeks of training over the short ROM (SR) and remained there for the duration of the detraining (i.e. the change was at least persistent, if not permanent). No such effect was observed in the LR group.

"By week 10, both groups displayed an average 6±2% strength reduction (relative to the post-training strength values), with SR not significantly above baseline (0±2%) in contrast to LR remaining significantly above both baseline (p<0.05) and SR (p=0.027) at weeks 10 and 12."

Overall, the changes in contractile force and the angle at which they were elicited reflect the structural changes that were brought about by the more pronounced muscle lengthening that's a prerogative of training over the full range of motion (ROM).

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To ensure that all participants conducted the complex exercises at the correct knee angle a goniometer was attached to their knees (photo velamed.com)

Bottom line: As far as the practical implications of his findings are concerned McMahon and Onambélé-Pearson reemphasizes that the specific muscle mechanics are of paramount importance, "when choosing a range of motion for a resistance training protocol." (McMahon. 2013)

With resistance training protocols that enforce a full range of motion having the ability to influence force and power production to a greater extent than protocols where the range of motion is not as extensive, he is therefore right to point out that it would be a mistake to allow your ROM to be compromised "in order to accommodate a greater absolute external load, in an attempt to increase the stress of mechanical loading" and advises coaches to "reinforce a more complete ROM, even when absolute load maybe reduced, in order to provide a greater internal stress and more potent stimulus for adaptation" (McMahon. 2013).

Aside from the fact that  this advice is obviously as relevant for trainees, like yourself. The one thing I would like to add to McMahon's "bottom line" is a reference to the structural changes and their importance in view of maintaining the strength gains you achieved. Moreover, it is, as you will be learning in an article I am still working on, likely that the extend of the observed and accompanying, but not evaluated changes in muscle structure facilitate future muscle gains. Therefore, you would in fact be ill-advised not to "leave your ego at the door" if you want persistent size gains and increases in strength over the full range of motion that do not vanish, when you are taking 2 weeks off.

Handpicked suggested reads:

• The Jack-of-All-Traits Leg Workout from the Sáez de Villarreal study I discussed on July 15, 2012, would also be something you may want to look into if you need some inspiration for your own routine.

  You Want Maximal Performance & Size Gains + Complete Thigh Development? Then Full Squats are For You! (read more)
• SuppVersity EMG Series - Gluteus maximus, Quadriceps femoris, Gastrocnemius, Soleus & More: The Very Best Exercises for Tree-Trunk Legs and Herculean Calves (read more)
• The Step-By-Step to Your Own Workout Routine Guide (read it)
• All posts leg training at the SuppVersity (read them)

References:

•  "hypothesis, n.". OED Online. March 2013. Oxford University Press. 6 May 2013 <http://www.oed.com/view/Entry/90588?redirectedFrom=hypothesis>.
• Eugene McMahon G, Onambélé-Pearson G. Impact of range-of-motion during ecologically valid resistance training protocols, on muscle size, subcutaneous fat and strength. J Strength Cond Res. 2013 Apr 26.[Epub ahead of print]