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Is high frequency better than low frequency to improve muscle and strength in trained lifters?

December 14 2018

Here is a recent study that compared 6 days/week to a 3 days/week workout program on muscle mass and strength in trained lifters.

Why did they do the study?

  • Lack of studies: There is lack of studies looking at the effects of frequency on muscle growth and strength.
  • Anecdotal Evidence: High-level weightlifters split their training volume into two training sessions in an effort to maintain the intensity.
  • Untrained subjects: Most of the studies on frequency used untrained subjects.

Photo Credit: Muscle & Strength, LLC

So the question is whether high frequency is better than low frequency in trained subjects in improving strength, muscle mass for a duration of 6 weeks.

What were the methods?

  • Population: Trained college-aged men (18-30 years) who were actively participating in resistance training for a minimum duration of 6 months (minimum of 3 days per week). That is, 1RM of 125% of their bodyweight, a bench press 1RM of 100% of their bodyweight, and a deadlift 1RM of 150%. So I would say intermediate lifters.
  • Exercise Program: The exercise program is shown in table below. The volume was equated and 6/week sessions lasted an hour, while the 3/week sessions lasted approximately 2 hours. The training focused on the main lifts as shown in table, but the subjects also performed exercises for biceps, triceps, lats, shoulders and such.
  • Outcomes: Strength using 1RM testing for the major lifts and body composition using an A-model ultrasound.
  • Sample size: They randomized 43 men into two groups.

What were the results?

  • Strength: There was no significant difference in strength between the groups for bench, deadlift and squats.
  • Body composition: Fat-free mass and fat mass also showed no significant difference between the groups.

What was the conclusion?

High-frequency (6/week) resistance training does not seem to offer additional strength and hypertrophy benefits over lower frequency (3/week) when volume and intensity are equated.

My Comments

Here are some of the aspects of the study that I thought was worth mentioning:

Hypothesis: The hypothesis of the study according to the authors is ” .. an increased training frequency would not lead to further improvements in strength and body composition when compared with a lower training frequency…”. That means, there will be no difference between the groups. 

  • First, you cannot prove the null hypothesis; you can only disprove it. I have seen this error in a number of studies during peer review. If you do want to show equivalence, you have to use a non-inferiority or equivalence study design. 
  • Second, a study is conducted when an intervention is hypothesized to be superior than the comparison group. Or the intervention is cheaper/practical/ less side effects compared to the comparator even though it may not be superior.  Why conduct a study when you know the 6/wk takes more time and is more burdensome but still not better than a 3/wk frequency?

 
Drop-Outs: In the high frequency group, out of 23 assigned, 11 dropped out.That’s a 50% drop-out rate in 6 weeks!  And it is very surprising that the authors thought this was not important to discuss in the paper, let alone report it. If I had to peer review, that would be my first question in a high frequency study.

  • Do drop outs matter? Imagine a weight loss supplement study that randomized 5 subjects to a control group and 5 into the diet pill group. At the end of 12 weeks, the diet pill group lost 5 lbs while the control group lost 2 lbs, and the difference was statistically significant. So the diet pill works! Now imagine, if I say 3 dropped from the weight loss drug group because they didn’t lose any weight. So if we had somehow tested them and included them in the analysis, the weight loss in the weight loss group would be 2-3 lbs and not 5lbs. That means, the weight loss drug is clearly not effective and is the truth! So drop-outs do matter a lot.
  • Intention-to-Treat: The technical term for including all the participants in your analysis is called Intention-to-treat (ITT). If you only include the participants, for example, that showed up for at least 75% of the sessions or adhered to the exercise protocol, then the analysis is called ‘per protocol analysis’.  ITT is the preferred analysis for all the leading medical journals. I would say 98% of exercise studies ignore the ITT principle. In my previous study, I report my results both in ITT and per protocol formats.
  •  
  • Anecdotal evidence: In fact, one large reason why we cannot trust anecdotal evidence is because they don’t count the negative hits. All the glowing testimonials are only coming from people who are alive and doing well. But the people who are dead or struggling in bed do not come back to say ‘thank you’ and hence forgotten. A scientific study, on the other hand, takes into (or should take into) account both positive and negative results.


In short, a study should analyze all the participants that were randomized in the beginning. If there are drop-outs, they should tell us why they dropped out. Here the participants dropped out either because the they couldn’t workout 6 days/ week or had adverse effects or their results were not as expected. If the latter, then the high frequency could be worse than a traditional 3 day/week program. So considering the large drop-out from the high frequency group, there is a high risk of bias in this study. 

Muscle Mass: One of the rationales for high frequency workouts for muscle growth is that protein synthesis comes down quickly in trained compared to untrained. In theory, at least, that suggests a higher frequency could be better in trained lifters. Fat-free mass showed 0.9 kg (2.5, 0.7) difference in favor of the high frequency group: A 2lb improvement in fat-free mass in 6 weeks is indeed a large improvement. But mind you, this improvement could be as high as 1.7lbs in the 3 days/wk group too if we repeat this study! Also, they used an A-Ultrasound for measuring muscle mass which is a cheaper version of the B-mode ultrasound and has questionable validity.

High-level weight lifters: In the introduction, the authors mention elite level weightlifters splitting their workout to support a high frequency workout. And it is true many weight lifters train a lift 6-8 times per week. Unfortunately, elite level lifters are a classic example of selection bias.  What you see are those 1% of athletes who survived the brutal training and competition in their lifetime, especially the ones on a high frequency training program. That means, the rest of them either got injured/plateaued/quit the sport. And this is exactly why you shouldn’t copy elite level athlete’s program or use them as a rationale for a scientific study on average lifters.

Also,  elite lifters have their nutrition, recovery, coaching, and rest almost close to perfect. Most of these lifters are professionals that means they only train and sleep. And unlike the participants here, these lifters might have taken years to slowly raise their frequency to their current level. This is just staggeringly different from college going students who participate in studies because they can earn a few dollars or a class credit. So be wary of elite level lifting programs.

Adverse effects: Any adverse effects like injuries or fatigue from training 6 days/wk? We have no clue since the authors did not bother to report them. What about attendance in each group?. Did they show up for the 6 day/wk workouts to actually claim high frequency? Again none reported. Any limitations reported? I thought they would certainly have a few limitations to talk about. I was wrong. None mentioned.

What if you want to try high frequency workouts?

Here are some practical tips so that you don’t kill yourself:

  • Pick one body part or a lift and try it;not every lift or muscle group as in this study.
  • Or have medium effort or light effort days like many programs than going at 100% intensity every day.
  •      
  • Do not go to failure on high frequency programs. Did they do in this study? I have no idea since they did not report it.
  • You can use high frequency to either spread your weekly volume or get more volume depending on your current program.
  • Just so you know, most of the gains made during a high frequency cycle may not stick when you climb down to a regular routine.


As a final note, critical thinking shouldn’t stop when you stumble upon a scientific study (as many do). In fact, critical analysis only begins and happens to be one of the fundamental steps to interpreting a study. And this is true even for my ‘impeccable’ studies.

Conclusion

  • The study showed that a 6 days/wk program is NOT better than 3 days/wk program to increase muscle mass and strength in intermediate lifters in 6 weeks. And considering the large drop-outs in the high frequency group, it is highly likely that high frequency could be worse.
  • Learning Tip: Next time when you read a study, check how many dropped out from each group and how it could have affected the results. Also, next time you hear a glowing positive review of a program or diet, think about how many negative reviews that were missed.

Reference

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Anatoly | Sun December 16, 2018  

Christmas comes early this year…
😊

Anoop | Sun December 16, 2018  

Thank you Anatoly! 😊 We have discussed this a lot in the forum years back!

What do you think?

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