Monday 1 December 2014

How to Personalize Your Rest Intervals for Optimal Results

When people think training variables, they often think about sets, reps and weight. However, what about the time between sets? Whether you want to burn fat, build muscle or improve athletic performance, rest intervals are another important training variable. Get this wrong you and you will fail to give your body the correct training effect and you can kiss your results goodbye. Finding your optimal rest intervals goes far beyond just following a generic chart from a book. Here is how to you can personalize your rest intervals and get the best results possible. 

Rest Interval Guidelines
Before we get into the important principles that allow you to personalize your rest intervals, let’s start with some general guidelines. When giving program design lectures to trainers or my university students, I often start with these basic guidelines:

Maximal strength: 3-5 min
Hypertrophy: 2-3 min
Endurance: <60 sec

However, while guidelines are a good starting point, your optimal rest interval times can depend on the following factors: 

Your goal should always dictate your training program. Before you go any farther, have a clear understanding of exactly why you are training.

Complete vs. incomplete rest
If you want to get faster, you need to fully recover
between sets of sprints
The purpose of a rest interval, is to (along with the other training variables: reps, load, sets and rep speed) give your body a specific type of stress. If your goal is strength, speed or power, you want complete rest. You want to leave enough time between sets so the next set can be just as heavy fast or  powerful as the previous one. Many people miss this. I have had athletes do a set of sprints for speed training, jog back to the start and then go again. This is not speed training, but simply fancy cardio. Many people new to strength, speed or power training rush their rest times thinking they have to be tired, keep their heart rates up and leave feeling tired. This is a misconception from mainstream fitness (that has its roots in bodybuilding and endurance training) and does not apply to strength, speed or power training. For more info on this, check out my post on What Training Should Really Feel Like.

If you are trying to build endurance or improve your conditioning, you want incomplete rest. You want to start your next set/round before you have fully recovered. In this case, you are trying to induce fatigue because you want your body to adapt by becoming more fatigue resistant. 

If you are trying to build muscle, you want (as suggested in the table above) to have a rest interval somewhere between the two extremes I have just described. Rest too short and you will not be able to lift enough weight to create sufficient mechanical tension on the muscles. Rest too long and you will not be able to create enough metabolic stress (which is also needed to stimulate muscle hypertrophy).

If you are training to burn fat, you should do some work with incomplete rest intervals (as with endurance/conditioning work) for increasing the metabolic demands and some with slightly more rest times (as is done with hypertrophy training) so you can move a little more weight and build some fat-burning muscle. 

Systematic stress
When writing programs, I not only look at the goal and what training effect I’m trying to create, but I also look at the systematic stress of the exercise. For example, a heavy set of deadlifts beats up your whole body and will take longer to recover from than an intense set of incline dumbbell curls. The more an exercise taxes the body as a whole, the longer your rest times will need to be and vice versa.

Current conditioning level
Someone with a high level of conditioning will be able to recover faster. This is in part because the aerobic system is used to recover between bouts of intense anaerobic (without oxygen) work. This is also because there tends to be an inverse relationship between strength and aerobic fitness. The more you focus on aerobic fitness and conditioning, the more your strength will suffer and this (as you will see next) also effects your rest intervals. 

Current strength level
The stronger you are, the more you take out of your body and the longer you need to rest. I see this all the time when doing team training with my athletes. The younger, weaker athletes are in and out significantly quicker than our strong veterans even if they do the exact same number of sets. As you get stronger, be prepared to give your body the longer rest intervals it needs. 

Fiber dominance
While most people are fairly balanced in their ratios of fast-to-slow twitch muscle fibers, some people have noticeable fast or slow-twitch dominance. If you are more fast-twitch dominant, you will need a little more rest between sets and the opposite would be true if you are more of a slow-twitch person.  

Exercise order
How you order your exercises also impacts the amount of rest needed. For example, if you are alternating sets (a fantastic method made famous by Charles Poliquin), you can significantly improve your time efficiency while keeping adequate rest intervals. For example:

Standard training example:
1) Incline Bench Press: 5x5, 2 min rest
2) Prone Dumbbell Row: 5x5, 2 min rest

Alternating sets example:
1a) Incline Bench Press: 5x5, 1 min rest
1b) Prone Dumbbell Row: 5x5, 1 min rest

In the standard training example, you would do 5 sets of incline bench with 2 min rest between sets. Then, you go to rows and do the same thing. In the second example, you alternate sets. You do a set of incline press, rest a minute to catch your breath, do a set of rows, rest a minute to catch your breath and then repeat the process 4 more times. In almost half the time, you could the same amount of work done while still giving adequate rest for strength/hypertrophy training.  

Also, if you arrange your exercises in a circuit, you can increase training efficiency even further. However, when using alternating sets or circuits, you still want enough rest before the next exercise so that you are not completely gassed from the previous one. I often prescribe 30-45 sec rest between exercises when writing programs with circuits. 

Do I need to be a slave to a stop watch?
Sometimes you see those people in gyms using a stop watch to meticulously time every rest interval. Do you have to be one those people? Most of the time, the answer is “no”. I do not time my rest intervals, but simply go by feel and principles listed above. I do however pay attention to how long my sessions take to ensure I’m not significantly altering my rest intervals from one session to the next as makes it difficult to monitor progression.

Sometimes you should meticulously monitor rest intervals. This is very important if you are using rest intervals as a method of progression. For example, if I was to run repeat 100m sprints for conditioning, I could progressively decrease the rest intervals (while maintaining distance, speed and sprint times) to progressively overload. This could also be helpful when using certain training methods such as contrast training or rest-pause training. 

Get the right amount of rest that you need to create your desired training effect and enjoy the results you get. 

Happy training! 

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