Do You Need to Lift Until Failure?

There seems to be some controversy about if you should lift till failure during every set.  Some people say that you always have to lift until you can’t push out another rep, while others say that it is not necessary to go to failure every set in order to gain muscle.  So who is right?

Well first off, let’s make sure that you are going to the gym for the right reason…

When you go to the gym, your goal for that lifting session should be to either:

  1. Gain more rock solid muscle mass or increase your strength
  2. Preserve your muscle mass (assuming you are on a calorie restricted diet)

Your goal when lifting should not be to lose fat.  This is done through dieting and cardio, not lifting.  A lot of the time the people who advocate not going till failure are thinking of lifting as a way to lose fat.

So now that we’ve established that you are basically looking to gain muscle and/or strength, should you go until failure to achieve this?  Moreover, should you go until failure for each and every set?

To determine this, let’s take a look at what actually happens to your muscle during a set:

When you first start your set, you feel pretty strong. Hopefully you have warmed up and your muscles are ready to start firing.  When you start lifting the weight, your body starts using your slow-twitch muscle fibers (ST) to do the work.  This is because they can last the longest and have the most amount of “energy” because they rely more on your aerobic metabolism, which gets constant energy from the air you breathe and your fat cells.  However, your slow twitch muscle fibers are not very powerful and don’t grow very large, so you do not want to focus on these fibers.  If you stopped lifting after just a few reps, you would be targeting mostly slow twitch fibers and never really see much growth.

When your body realizes that you need more power than the slow twitch muscle fibers can provide, it starts to turn to the fast twitch fibers (FT-A and FT-B, or Type IIa and Type IIb).  FT-A starts to get used first, and the power output of FT-A is in between ST and FT-B.  FT-A can also last longer than FT-B, but not as long as ST.  FT-A are used for the majority of your set, until the very end (unless your reps are very low, like 1-5).  FT-A fibers can grow quite a bit, but a lot of the growth is from increased capillary density and mitochondrial density; basically, a lot of the growth you’ll see isn’t from the actual muscle fibers increasing, it’s from a lot of the “other stuff” inside the muscle getting larger and denser.

Finally, when you are towards the end of your set, and you have to really push yourself to keep going, your FT-B kicks in. FT-B have the most power, but last for a very short period of time, which is the reason why you might be able to get your 7th rep with just a little bit of struggling, but then you are unable to get your 8th rep at all.  FT-B have low mitochondrial and capillary density, so most of the growth from these fibers will be the actual muscle fibers increasing, unlike FT-A. When people talk about getting “stronger” it is the FT-B that grew (or it was a neural adaptation, but that’s outside the scope of this article).

Alright, now that we got all that covered, let’s get back to our question:  Do you need to go to failure?

Well, you should probably be able to see by now that if you do not go till failure, your FT-B fiber will not be used as much as it could be, but your FT-A fibers will still be mostly exhausted.  So if you stop 1-2 reps short of failure, your FT-A fibers might still grow, but probably not FT-B.

If you were to do this, then you would still notice a size increase, however as I said before it will be a lot of capillary growth and increases in the number of mitochondria (called sarcoplasmic hypertrophy), which does not create a lot of increase in force production.  Therefore, you will be getting bigger, but not much stronger.

This is a problem because if you continue to do this then you will eventually reach a plateau and stop growing.  There is a limit to how much increase in size you can have without an increase in strength and vice-versa.

A lot of people might actually do this unconsciously, not pushing themselves as hard as they really can.

If you go till failure then most of the growth will be myofibrillar hypertrophy which is an increase in the number of myosin/actin filaments (sarcomeres) inside the cell.  Essentially, you are getting stronger.

Getting stronger will allow you to use heavier weights and, by doing so, further increase the damage and growth of both FT-A and FT-B.

However, targeting your FT-A fibers still has its benefits.  After sarcoplasmic hypertrophy, your body is able to store more ATP in your muscles, which gives you more energy when lifting (not strength, but energy) and plays a big role in protein synthesis.  Though, I would recommend that you target your FT-A fibers by doing longer sets (about 9-15) rather than just stop short of failure as this will allow for maximum hypertrophy.

So in the end, should you go till failure? Yes, you should.  Each set you do should be aimed at gaining more muscle or strength.  You should not even perform any more sets than ones going to failure because it will just breakdown the muscle more (read: recovery will take longer) without stimulating much of a growth response.

As a last note: if you are performing sets in the rep range of 1-5, then going to failure does sort of become optional at this point. This is because, since the weight is so heavy, the fast-twitch muscle fibers come into play right from the beginning. Also, since the weight is so heavy, going to failure on the first set of these might take such a large blow to your nervous system that you can hardly lift anything on your subsequent sets. In this case, it would probably be to your advantage to stop just short of failure so that you are able to, in the end, perform more total reps with that heavy weight and do more total Work.