Thursday, September 8, 2011

Is it better to workout with heavy weight / low reps or light weight / high reps?

That depends.

Let's start by looking at low weights and high reps. Occasionally, I come across publications and individuals who are now suggesting that light weight and high repetitions will result in the best muscle gain, or better yet, suggest that this type of workout protocol will actually result in "toning". I think that some reasons for this are due to problems interpreting a recently published study.

Released last year, the following study has been taken out of context and misinterpreted in the media: Burd NA, West DWD, Staples AW, Atherton PJ, Baker JM, et al. (2010) Low-Load High Volume Resistance Exercise Stimulates Muscle Protein Synthesis More Than High-Load Low Volume Resistance Exercise in Young Men. One reason for this post is that I recently came across a reporter looking for additional supporting evidence that this methodology would be a better way to workout.

Take this study at face value. If you read into it too much, there are some problems that come up:

  • The study demonstrates increased muscle protein synthesis. Key point: protein synthesis. Hypertrophy (muscle development) is the result of protein synthesis after protein degradation has been considered (it's not in this study). Take the study at face value - it shows increased protein synthesis. It does not say "hypertrophy".
  • The study clearly states "high volume". This can not be understated. The protocols are vastly different in work load, and the low weight, high volume workout is dramatically different. By using leg extension, we are subjecting the quadriceps to a unique workout situation of constant load. After many repetitions, we achieve an occlusive effect that dramatically increases the work load. Also, the design leaves the "low volume" group with much less volume (as stated). Part of the issue is an unrealistic program design leaving the heavy weight / low repetition group with a very low work volume. Is this the work load that we want? Simple exercise versus complex? Open chain? Leg extensions serve a great purpose in a rehabilitative and sometimes a corrective setting, but do they really fit in with a workout where we are trying to get the most bang for our buck?

Since the study is pretty much saying, "a bigger (higher volume) workout will lead to part of the equation of more muscle development (you'll kind of increase muscle mass, unless you break down too much muscle)", I don't really find a lot of inherent value in it. On the other hand, discussion from this study may actually lead towards prescribing higher volume work for those who only have access to resistance machines. It does say that there is definitely some value for this type of workout. For high-school team athletes with less supervision, or special populations, or endurance athletes, this is essentially prescribing an extensive or intensive interval program. I've trained individuals with these programs with great success, as it is a very effective method of improving muscle endurance and increasing lean muscle mass. For people with less training history or those who may have a hard time with perceived exertion, this is often a preferred workout. However, it is NOT the best way to achieve hypertrophy. Not by a long shot.

Without getting into the fallacy of "toning" through this type of workout (low weight / high reps), we need to workout with sufficient intensity to release sufficient growth hormone and IGF-1 for protein synthesis as well as the metabolic benefits to favorably affect body composition. Heavy weight and lower reps are found to be the best combination for this in the vast majority of research literature.

ACE actually cites the study as evidence for an equal or similar benefit from program design using high reps and low weight on their main blog. What? We have to be careful to read studies with a critical eye. In this case, that's not what the study shows. While this study has some components of good design, it serves mostly as a catalyst for discussion. It's very healthy to consider this concept with special populations and deconditioned individuals. It also serves as a reminder to consider alternative methods of reaching a sufficient work volume on days with high DOMS, fatigue, intensive or extensive interval training, or an additional light workout. But to consider the findings of this study evidence that we can workout like this and get the most bang for the buck? Try again. To suggest that is to misread the title of the study and then continue to misinterpret the findings throughout the study.

Even ignoring this study altogether, many people cite anecdotal evidence that this type of workout does the trick. I have no doubt that their approach works. But I would argue that most people that see more value in the low weight / high repetition workout have no idea what their current 1RM is. They are definitely achieving much higher total workload through the low weight / high reps design. It's because they can't achieve the same workload through a heavier weight / lower rep regime, since they are aiming too low in weight or PE. These folks might be getting some results, but they are doing it the slow way, and are likely missing out on their most profound lean muscle mass and body composition results. Working with a intelligent trainer or coach who could more accurately determine a %1RM, they would definitely achieve their goals with a heavier weight / lower repetition workout, in significantly less time.


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