Tag: Hypertrophy

How Long To Rest Between Sets?

How long to rest between sets?  It’s a question every new lifter asks, and an issue that experienced lifters are constantly trying to manipulate to maximize their results.  If you walk into a gym that houses serious strength athletes you might see them take 5-10 minutes between their peak training sets.  Once you start doing the math and realize how long you will be in the gym if you are taking five or more minutes between sets it creates a long enough workout that it becomes demotivating.  Most people just don’t have two hours to spend on their daily workout.

In the average commercial gym where most people are concerned with how they look in addition to getting stronger we see rest times that vary from less than a minutes to a few minutes.  Often the driving factor is if someone is working out alone or socializing with others.

There is a general gym belief that when you are training for hypertrophy (increased muscle size) then rest periods of around a minute are optimal.  If you are training for peak strength development then approximately 3 minutes tends to be the most common advice.  Those trying to maximize calorie burn are keeping their rest periods to below a minute.

So what is the right answer?  Should you be jumping right to your next set or sitting back and watching the minutes go by?  In a 2016 study Schoenfeld et al. attempted to help answer this question by looking at changes in strength and size when subjects used either a 1 minute or a 3 minute rest period.  Test subjects were broken into two groups and with the exception of their rest period did the exact same workout, 3 times a week for 8 weeks.  Each workout consisted of 7 exercises, each done for 3 sets of 8-12 repetitions.  The subjects were tested for maximum strength with their 1 repetition maximum for the bench press and back squat.  Muscle endurance was tested with a bench press done at 50% of the 1RM done to failure.  Muscle growth was measured utilizing ultrasound at the elbow flexors (biceps and brachialis), triceps and quadriceps.

All of the subjects were injury and drug free men ages 18-35 with at least 6 months experience lifting weights.  This ensured that any gains were not the result of early neurologic adaptations to beginning a training program.  The subjects were pair matched to ensure that there were similar subjects in each experimental group.

The training programs consisted of barbell back squats, plate loaded leg press, leg extension, flat barbell bench press, seated barbell military press, wide grip pulldowns and seated cable rows.  During each set of 8-12 repetitions the subjects trained to momentary muscular failure and the weight was adjusted between sets to keep the subjects achieving failure in the designated repetition range.  There was an attempt to consistently raise the weight as subjects were able to.  This selection of exercises and approach towards managing loads is very similar to what is commonly seen in many fitness settings.

The Results

There was clearly a winner when it came to strength improvements.  In the back squat both the long rest period (3 min) subjects and the short rest period (1 min) subjects saw statistically significant improvements, however the long group had a 15.2% improvement and the short group had a 7.6% change.  For the bench press the long group increased 12.7% while the short group only improved 4.1%.

When it came to the the 50% bench press test for muscular endurance both groups saw significant improvements though we again see the long group outpacing the short group with a 23.2% change as opposed to a 13% improvement.

While the existing common recommendations for muscle growth are around the 1 minute period, the results of this study suggest just the opposite.  For the elbow flexors the long group had a 5.4% improvement and the short group had a 2.8% change.  When it came to the triceps the difference between groups was even more notable.  The long group improved by 7% while the short group only saw changes of 0.5%.  In the anterior quadriceps the pattern continued with the long group seeing a 13.3% change while the short group had a 6.9% improvement.  For the vastus lateralis the long group changed 11.5% and the short group 10%.

While it was expected that we would see strength improvements that clearly favored the longer rest periods it was surprising to see that muscle growth also favored the longer rest.

One notable aspect of the research design that has also popped up in other studies is that the subjects performed their exercises to momentary muscular failure on all of their working sets.  There seems to be a trend within the research that when sets are taken to failure, more significant outcomes are seen.  Now don’t go rushing back to the gym and swear that every set needs to be done this way.  This isn’t a topic that has been closely studied, it is just an observation that some researchers and I have made.  In studies where the volume of work is more closely controlled to match up different experimental groups it often means certain subjects are not training to failure and when those studies are compared to ones where subjects are training to failure often differences are seen.

This dovetails with the question of training volumes.  In this study the subjects in the longer rest group recovered more and as a result were able to lift with more total volume then the shorter rest subjects.  To what extent this extra volume that the longer group was able to lift drove their greater levels of improvement is an important question to ask.  Other studies have also raised similar questions, if variables such as training to failure or more sets which produced more volume lifted drove the results or if there was another factor responsible for the differences seen.

This study was done in younger men, aged 18-35.  We cannot say for sure if the same results would be seen in women or what differences we would encounter with older subjects.  Often younger men respond differently then 40 or 50+ individuals.

The Take Away

So what lessons can we take away from this study?  First, if you are looking for a very straight forward strength training plan that can produce results the workout used in this research is a great model to follow.  The researchers did a nice job of choosing a program that is similar to what you would see in today’s gym settings for the average person looking to gain strength and size.  Yes we can change a few things around, I would.  It’s not perfect but it is a good model to think about.

Secondly, if you want to maximize the development of strength or size it may be time to stop following the high intensity model of high volume/low rest metabolic workouts that have become popular over the past few years.  Those workouts are still great and have a place in many programs but you have to think about what your training objective is.  If it is to improve anerobic work capacity and maximize calorie burn they may be the perfect choice.  If you are focused on maximizing strength or size gains you might want to slow down and take more rest between sets.

Should you take a full three minutes rest between all of your sets from now on?  Possibly but that creates a long workout and the reality is most people don’t have that much time to spend in the gym.  It is perfectly fine to shorten the rest time during your warm up sets.  Researchers have not reached any conclusion on the ideal rest period and other studies have found positive results at 2 minutes.  If you want to maximize your results but speed things up 2 minutes is probably fine for the average person.  Those at more elite levels should consider going a little longer.  And remember there were still positive improvements with subjects who utilized the 1 minute rest period.  The results may not be as great within an 8 week period but when you balance time demands into the equation it may be perfectly fine to stick with the shorter rest periods.  I would rather have someone come into the gym and rest for a minute or less between sets and get a good workout in then have them not workout at all because they didn’t have the time available to maximize their rest periods.

You can also consider utilizing the rest periods in a productive way.  No one says you have to sit around for 2-3 minutes between sets.  The trick is to make sure you are not loading the muscle groups that you are training.  While most people tend to not think about it, you also need to consider the impact on your nervous system of what you are doing.  If you are training legs that day, yes doing some sets of arms in-between does allow your legs muscles to rest but the nervous system is still being loaded and contributing to the buildup of fatigue. Don’t just think that training an unrelated body part means you are getting your optimal rest.  The nervous system is a key component to your training and any fatigue you put into it has to be considered.

If you are doing some sort of training split where you are not training your entire body that day you can consider doing some mobility exercises in-between sets that focus on the body parts you are not training that day.  Most of us can benefit from more flexibility and this approach ensures this important aspect of self care is not ignored as it often is.  Let’s face it, mobility work is the most commonly skipped part of a workout program and if you plan for it to be done during the workout between lifting sets you are far more likely to consistently get it done.

If you are doing a full body workout I suggest you focus on a specific movement pattern/body part first so as you move on through the workout you can then utilize the rest periods to do your stretching for the parts of the body you focused on in the prior training block.

There you go.  Time to rethink how long you are resting between sets and how you are utilizing those seconds.  There is no perfect answer yet but there are better answers.  Let your training objectives drive your decisions and most importantly, keep lifting.

Schoenfeld, B., Pope, Z., Benik, F., Hester, G., Sellers, J., Nooner, J., Schnaiter, J., Bond-Williams, K., Carter, A., Ross, C., Just, B., Henselmans, M. and Krieger, J.  (2016) Longer Interset Rest Periods Enhance Muscle Strength and Hypertrophy In Resistance-Trained Men. Journal of Strength and Conditioning Research. 30:7: 1805-1812.

Lift Lighter to Get Bigger

There are generally a few main objectives that individuals have when they start working out.  Some want to get strong, some improve their endurance and conditioning, some want to focus on improving their athletic performance and others want to lose weight or tone up.  Then there are those who are focused on gaining muscle.  Downing protein shakes and searching for that perfect combination of exercises and intensity techniques to squeeze every bit of muscle growth out that they can.  Traditionally we have believed that higher loads (heavier weights) stimulate more muscle fiber and the related biochemical factors that do the best job of coaxing out precious muscle growth.  Certainly if you follow the bodybuilding literature and half of what is written on the internet the notion of harder and heavier is pushed over and over, but what if it is wrong?  What if the path to developing more muscle growth is actually…lighter weights?

Over the past few years a body of research literature has been growing showing that training at lighter loads may be an equal if not more effective way to stimulate hypertrophy (muscle growth).

Ogasawara et al. (2013) compared the effect of high-load bench presses at 75% of 1 repetition maximum (1RM) to low-load presses performed with 30% 1RM.  When performing the high-load exercises the subjects did 3 sets of 10 reps, 3 times a week for 6 weeks.  The low-load protocol was 4 sets to failure also performed 3 times per week for 6 weeks.  MRI images of the triceps and pectoralis major (chest) showed similar increases for both groups.  Additionally both groups showed increases in strength though the high-load group did see a larger increase.  One of the interesting aspects of this study was that it used a within-subject design.  The subjects trained for 6 weeks using 75% of 1RM, took twelve months off from training then performed the 30% 1RM program.  This addresses some of the biological issues involved with using different subjects though the authors theorized that some of smaller strength level improvements seen in the low-load portion of the study could be the result of residual strength improvements from the high-load training done the previous year.

Measureable growth in muscle mass is challenging to quantify and takes a long time. In the research setting various measures of muscle protein synthesis are used to determine if muscle growth is being stimulated and to what extent.  Increased muscle protein synthesis (MPS) does not magically mean that someone will be walking around looking like Arnold Schwarzenegger circa 1980 but a consistent program that is followed for an extended period of time coupled with proper supportive nutrition and recovery should result in someone increasing their muscle mass within their natural genetic capacity.

Burd et al. (2010) examined the effect of different loads and volumes by utilizing three different training conditions.  The first group utilized a resistance that was 90% of 1RM and performed 4 sets to failure.  The second group used 30% of 1RM and preformed 4 sets to a volume that was work matched with the 90% group so they stopped before failure.  The third group also used 30% of 1RM but performed their 4 four sets to failure.  Myofibrillar muscle protein synthesis, sarcoplasmic protein synthesis and a mixture of the two were measured at 4 hours and 24 hours after exercise.

In the mixed protein synthesis at 4 hours all 3 groups were elevated but the 90% and 30% failure groups were significantly more so then the work matched group.  At 24 hours all three conditions continued to be elevated with the 30% failure group clearly showing the highest values.  With myofibrillar protein synthesis we again see increases in all 3 conditions while the two failure groups show significantly higher rates of synthesis.  At 24 hours only the 30% to failure group still shows significant increases.  Similar changes were seen in sarcoplasmic protein synthesis where there failure groups showed increases at 4 hours though the work matched group did not.  Again at 24 hours only the 30% failure group showed elevated levels.

This study shows low-load high volume training (30% failure) to be more effective at increasing muscle protein synthesis then high-load low volume training.  How high-load high volume training would measure as compared to low-load high volume and high-load low volume training would be an interesting follow up study.

Regarding myofibrillar protein synthesis, when the impact of the 90% failure group and 30% work match group are considered, it appears that contraction intensity has a greater impact on synthesis rates at 4 hours while volume of exercise which is more related to the degree of muscle fiber activation affects the duration of muscle protein synthesis.  The real question that is then raised is what the impact of 24 hour as opposed to 4 hour myofibrillar protein synthesis values are when it comes to actual hypertrophy. Regarding sarcoplasmic and mixed protein synthesis, the similar results also support the notion of the benefit of low-load high volume to failure training.  We’ll save the discussion of what the meaning of different types of muscle protein synthesis mean for another day.

It is generally believed that early strength gains which occur in new lifters are the result of neural adaptations that occur in the first few weeks of training and are not related to muscle hypertrophy.  Jenkins et al. (2016) set out to examine the impact of resistance training on untrained men.  Both strength and muscle growth were measured at 2 and 4 weeks.  The subjects trained 3 times per week using either 80% of their 1RM or 30% of 1RM, performing 3 sets to failure.  Despite the previously untrained status of the subjects, similar increases in muscle thickness were seen in both groups.  Ultrasound imaging was used for this measure.  While total training volume was the same for both groups the 30% subjects experienced significantly more time under tension (181%) then the 80% group.  The authors theorized that the increased time under tension was possibly the factor responsible for the stimulus of muscle growth in the 30% group.  The 80% group also demonstrated significant increases in strength that were not seen in the 30% group, further supporting the both the use of heaver resistance for strength gains and the separation of strength and hypertrophy training objectives.

Kumar et al. (2009) had one of the most interesting findings.  They had subjects perform at 20%, 40%, 60%, 75% and 90% of 1RM.  Volume was adjusted so that it was work matched.  The 20% group did 3 sets of 27 reps.  The 40% group did 3 sets of 14 reps.  The 60% group did 3 sets of 9 reps.  The 75% group did 3 sets of 8 reps and the 90% group did 6 sets of 3 reps.   When myofibrillar protein synthesis was measured there was minimal change between 20% and 40% but a significant rise at 60%.  What stands out is that there was no appreciable change between 60%, 75% and 90% suggesting that to maximize protein synthesis it might not be necessary to use heavier and heavier levels of resistance.  Again differentiating maximal strength development from hypertrophy, the evidence suggests higher loads aren’t always the optimal path towards muscle growth.  The replication of this study with subjects training to failure at the higher loads would further delineate if there is a difference between 60%, 75% and 90% or if individuals can achieve optimal results with more moderate loads.  This study clearly shows 60% 1RM is preferable to the lower percentages seen in other studies but you have to take note that the loads are work matched where the studies that show more significant hypertrophy or muscle protein synthesis at lower loads use training protocols that have subjects going to failure.  That one aspect seems to be the key element.

It appears time and again that the studies using training to failure show different results than those that work match.  The issue of time under tension being a major factor for this has been theorized by multiple researchers.  Burd et at. (2012) looked at this specific question, measuring the effect of time under tension with low load training on muscle protein synthesis.  They compared a slow movement with a 6 second lifting and 6 second lowering phase on one leg to a rapid movement using a 1 second up and 1 second down pace on the other.  Both trials used 30% of 1 RM.  The slow leg performed the exercise to failure and the fast side performed an equivalent number of repetitions, not going to failure.  This created a large difference in time under tension for the slow leg as compared to the fast.

Myofibrillar protein synthesis was higher in slow training at the 24-30 hour recovery window.  In the first 6 hours of recovery only the slower group saw elevated mitochondrial and sarcoplasmic protein synthesis (114% and 77%).  These findings along with previous research by the authors lead to the speculation that “maximal fibre activation, and not percentage of maximal muscle strength, is fundamental to induce maximal rates of muscle protein synthesis and we would hypothesize other purportedly important variables that are thought to dictate hypertrophy are largely redundant in their ability to elicit an anabolic response to exercise so long as high levels of muscle fibre recruitment are attained”.

While this is just a sampling of the research on this topic it does begin to present a strong argument for altering some of our closely held beliefs about building muscle.  This doesn’t mean we should stop heavy training.  The research did not say heavy lifting does not produce quality muscle growth.  It does.  And the research clearly shows that heavier loads do a better job of building more strength which is certainly an important objective.  Even if hypertrophy is the primary goal, if more strength is developed in the heavy cycles, when lighter loads are used, they will be heavier when you consider what percentage of 1 repetition max is being used and in theory that should stimulate even more muscle fiber recruitment.

So how should you proceed and put this knowledge to use?  If your main objective is muscle growth, or even if you are just doing a hypertrophy cycle in your training you may want to consider occasionally mixing in a 4-8 week block of lighter loads to failure, then proceeding to a heavier hypertrophy block or a heavier strength block.

If you are the average person who doesn’t want to lift really heavy, an older adult or working with one of those groups and trying to help them add some muscle mass but keep injury risk low then this approach may be beneficial.  Working with more moderate loads can give you some much desired muscle growth in a safer and far more comfortable approach.

If you are a strength or performance athlete you already know you cannot train at your maximum loads year round.  Your joints and muscles need a break from that constant intense stress but you don’t want to just stop training and improving.  Taking a few weeks to train at lighter loads will allow you to stay in the gym and making valuable progress.  If you can increase your muscle mass you increase your potential to develop more strength and power when you return to heavier lifting.  And if your joints are feeling a bit refreshed from facing lower loads and getting to fully recover then all the better for your upcoming training.

Now that you are armed with the knowledge don’t be afraid to get out there and put less weight on the bar.  Just remember to take your sets to failure and slow the repetition pace down.

Burd, N., Andrews, R., West, D., Little, J., Cochran, A., Hector, A., Cashaback, J., Gibala, M., Potvin, J., Baker, S., and Phillips, S. (2012) Muscle Time Under Tension During Resistance Exercise Stimulates Differential Muscle Protein Sub-Fractional Synthetic Responses in Men, J Physiology, Jan 15; 590 (Pt 2): 351-362.

Burd, N., West, D., Staples, A., Atherton, P., Baker, J., Moore, D., Holwerda, A., Parise, G., Rennie, M., Baker, S., and Phillips, S. (2010) Low-Load High Volume Resistance Exercise Stimulates Muscle Protein Synthesis More Than High-Load Low Volume Resistance Exercise in Young Men, PLoS One, Aug 9;5(8):e12033.

Jenkins, N., Housh, T., Buckner, S., Bergstrom, H., Cochrane, K., Hill, E., Smith, C., Schmidt, R., Johnson, G. and Cramer, J. (2016) Neuromuscular Adaptations After 2 and 4 Weeks of 80% Versus 30% 1 Repetition Maximum Resistance Training to Failure. Journal of Strength & Conditioning Research, Aug: 30(8):2174-85.

Kumar, V., Selby, A., Rankin, D., Patel, R., Atherton, P., Hildebrandt, W., Williams, J., Smith, K., Seynnes, O., Hiscock, N. and Rennie, MJ. (2009) Age-Related Differences in the Dose-Response relationship of Muscle Protein Synthesis to Resistance Exercise in You and Old Men.  The Journal of Physiology Jan 1; 587(Pt 1): 211-217.

Ogasawara, R., Loenneke, J., Thiebaud, R. and Abe, T. (2013) Low-Load Bench Press Training to Fatigue Results in Muscle Hypertrophy Similar to High-Load Bench Press Training. International Journal of Clinical Medicine 4: 114-121.