Workout Intensity – How Many Reps Should You Do?

What is Workout Intensity?

“Workout Intensity” refers to the amount of physical effort you put into your workout.

Four Components of Workout Intensity

There are many different definitions of Workout Intensity, but it can be broken down into four main factors:

1. Number of Reps per Set
2. Load (How much weight to lift)
3. Failure
4. Rest Intervals

1. Number of Reps per Set

One of the most common questions in weightlifting is: how many “reps” (repetitions) of an exercise should I do?

A “Rep” is defined as the action of moving a weight from point A to point B once.
A “Set” is the consecutive execution of a number of reps.

Here’s an example to help you understand the meaning of “Rep” and “Set”: when you lift a dumbbell for your bicep curl once, it’s considered as one “rep”. When you perform 10 reps in a row and rest for a short while, that is considered to be one “set” of 10 reps. The number of reps to perform depends on your training goals. See below:

1-5 reps per set = Strength
6-8 reps per set = Mass gain with some strength
9-12 reps per set = Slightly less mass gain with some endurance
12-15 reps per set = Endurance with some mass gain
15-20 reps per set = Largely endurance

However, it is important to note that each rep range will improve all three aspects of strength, size and endurance respectively to some degree. For example, even though the 1-5 rep is ideal for “strength”, it does produce size gains as well (Olympic lifters train in this range and they are pretty big!). Similarly, even though the 15-20 range states “largely endurance”, it will also result in some mass gain due to the muscle’s reaction to muscular fatigue (more on that in another article).

The aim here is to choose the rep range that is MOST IDEAL for your training goal. For example, if you want to build muscles, the 6-8 and 9-12 ranges are most suitable. If you are mainly training to increase strength, the best rep range is 1-5.

2. Load (How much weight to lift)

How much weight should I use? This is a common question that people ask when they first start working out. Advanced lifters know this instinctively but it may be a little trickier for people who are new to weightlifting. To figure this out, just follow the two simple steps below:

– Step 1. Determine the rep range based on your workout goal (Strength, Mass gain or Endurance).
Refer to the above section on rep ranges. For example, if your workout goal is to increase muscle mass, your ideal rep range would be 6-8.

– Step 2. Based on the rep range, determine your Load.
Let’s assume you are going to perform 3 sets of 8 repetitions because your workout goal is mass gain.

Now, choose a LIGHT weight that allows you to perform these 3 sets. Always start with a light weight to prevent injury.

  • If you manage to reach 8 reps easily for all 3 sets and can probably go on to 10 or more reps, increase the weight used.
  • If you fail to reach 8 reps for all 3 sets (maybe hitting 6 or 7 each), you should use a lighter weight.
  • If you just manage to reach 8 reps for all 3 sets, this is the correct weight. Use it!
  • However, this is probably the most common scenario: you manage to reach 8 reps for the first two sets, but in the third set you get to 1-2 reps shy of 8 reps. This weight is fine too. Use it!

3. Failure

In weightlifting, training to failure means performing a set to the point where another rep cannot be completed. For example, say you were attempting 3 sets of 8 reps on the bench press, and you have completed 7 reps on the third set. On the 8th rep, you push yourself REALLY hard and give it your ALL but you are unable to complete the rep. This is training to failure.

This method of training was popularized by Arthur Jones. His High Intensity Training (HIT) method advocated that lifters consistently trained to failure (he termed it “Momentary Muscular Failure/Fatigue”) in order to maximize muscle growth. Below, I elaborate on the advantages/ disadvantages of Failure and conclude on whether you should train to failure.

– May result in greater Mass and Strength gains
Some studies have suggested that training to failure results in greater mass and strength gains. The argument is that by pushing yourself to the limit, you get full recruitment of all your muscle fibers. However, this finding is controversial and has not been fully proven yet.

– Progression
Training to failure means you are forcing yourself to lift a heavier weight or an extra rep. This is known as Progressive Overload. As I will explain in a later section, progressive overload is the key factor to achieving workout results. However, not everyone may be able to physically/mentally withstand the stress on the body caused by training to failure – see below!

– May cause Physical Injury
Training to failure consistently may cause long-term injuries to your body. By constantly over-pushing yourself in your workouts, you may tear/wear-out/damage your muscles and joints.

– May burn-out your Nervous System:
Going to failure can be very damaging to the body’s central nervous system (CNS). In other words, it may burn you out mentally. Some people who over-push themselves at the start of a workout find that they become unusually exhausted after a short while. They are unable to finish their entire workout, even though they do not feel any physical/muscular fatigue. This is due to their CNS breaking down!

So Should You Train to Failure?
People have achieved results from BOTH training to failure and not training to failure. My advice is that unless you are extremely confident your body is able to handle both the physical/ mental stress of reaching failure, it is best not to push yourself to the limit during your workout. In most cases, you should stop 1 or 2 reps short of failure.

4. Rest Interval

Last but not least, you need to determine your Rest Interval! This is a very important step because the amount of rest between sets/ exercises can directly influence the effectiveness of your workout routine.

a) How long should you rest between each SET?

The amount of rest between sets depend on your workout goal. See below:

Strength Gain: 3 to 5 minutes.
Endurance: 20 to 30 seconds.
Muscle Gain: 90 to 120 seconds.

Strength Gain: 3 to 5 minutes
– Full recovery of Phosphagens
Phosphagens are energy storage compounds found in your muscles, and are required for powerful and explosive muscle movements. When training for strength gain, the load is usually very heavy because you only do a few reps (see above: Number of Reps per Set). Hence, the workout will be relatively intense, and your body will require phosphagens to produce the large amount of energy needed. The rest interval of 3-5 minutes allows for full recovery of phosphagens between sets so that you can produce the greatest amount of energy/force possible and achieve maximum results!

– Higher Testosterone Levels
Research has shown that this rest interval allows for the highest testosterone level production/ recovery. Testosterone is an essential hormone needed for strength and mass gains.

– Full recovery of Central Nervous System (CNS)
This rest period allows for complete recovery of your CNS and prevents it from breaking down, allowing you to achieve the most out of your workout.

Endurance: 20 to 30 seconds
Optimal Metabolic Accumulation
Metabolism refers to the set of chemical reactions required for sustaining your body functions. When you work out, your metabolism increases to produce the energy you need. Metabolites are the by-products of metabolism. Hence, since your metabolism increases, higher amounts of metabolites will be produced. One of these metabolites is Lactic Acid. Yes, this is the “bad” chemical that gives your muscles that feeling of fatigue and soreness! Resting for a short period of 20-30 seconds allows for higher lactic acid accumulation in the muscles, forcing your body to improve its capability to deal with lactic acid. Consequently, this improves your muscular endurance, and allows you to sustain performance for a longer period of time!

Muscle Gain: 90 to 120 seconds
– Higher Growth Hormone Levels
Studies have shown that Human Growth Hormones are produced in the greatest amounts when you rest within this time range, as compared to resting for longer periods. Higher growth hormone levels will naturally lead to greater muscular hypertrophy and size gains.

b) How long should you rest between each EXERCISE?

This is much less complicated than determining the rest interval between sets. As a rule of thumb, your rest period between exercises should be as long as the rest period between each set of the previous exercise. For example, let’s say you are doing three sets of Bench Press followed by three sets of Pull-Ups. If you rested 90 seconds between each set of bench press, you should rest about 90 seconds as well after finishing your third set of bench press before going on to your first set of Pull-Up.

Congratulations! You should now have a clearer idea of workout intensity. You just need to finish this workout guide to become a full-fledged expert! Now that you have learned how to determine your workout intensity, the next step is to figure out your workout volume.

This article is part of a completely FREE and FANTASTIC workout guide to teach YOU how to gain muscles and lose fat. See below:

The Ultimate Guide to Working Out

1. Five Steps to Achieving Your Workout Goal
2. The Ultimate Diet to Build Muscle and Lose Fat
3. How to do a Proper Warm Up
4. Workout Frequency/ Split – How Many Times Per Week Should You Work Out?
5. Workout Intensity – How Many Reps Should You Do?
6. Workout Volume – How Many Sets Should You Do?
7. How to Build The Best Workout Routine
8. Progressive Overload – The Secret to Getting Workout Gains!
9. Workout Routines to Build Muscles and Lose Fat Fast

4 Responses to Workout Intensity – How Many Reps Should You Do?

  1. Hey so i wanna gain strength an muscle so would 3 sets of 8 reps for each xersise be fine

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