Time-Based VS Rep-Based Sets: Which Is Best for Your Goals?

Looking to enhance muscle growth or muscular endurance? Whether you use time-based versus rep-based sets can make a huge difference. Leveraging these two types of sets can boost the efficacy of strength training and resistance exercise for your personal training clients.

The Purpose of Time-Based Sets and Rep-Based Sets

Both strength and resistance training techniques can be performed via time- or repetition-based sets. How you structure muscular training with sets can greatly impact the results.

What Is the Difference between Time-Based Sets versus Rep-Based Sets?

Strength training with rep-based sets uses a specific repetition number or rep range as the goal for each set.

Time-based sets don't require specific repetitions such as five reps. Instead, time-based sets are counted by the time lapsed, such as 30 seconds per set.

Although interval training has been around in various guises for a while, it wasn't until the popularity of high-intensity interval training (HIIT) that time-based repetitions became more common in weight training.

Both timed and rep-based sets work on muscle fibers to increase muscle mass, strength, and endurance, but each type has its pros and cons.

How Can Time-Based Sets Help You Reach Your Fitness Goals?

When are time-based sets optimal in fitness training? A timed set can help add an element of cardio to a strength training routine. But you don't have to move fast to do a time-based set. Timed sets can simply be a way to work out without having to focus on counting repetitions.

Timed sets may more naturally fit with certain types of exercises such as push-ups as opposed to handling heavy weights on the bench press. But they can be structured in any number of ways.

Personal trainers can also consider implementing time under tension, which is a way to evaluate training intensity by how long a muscle is engaged with a weight. This is not the same as a time-based set but still uses time as the basis for planning a fitness regime.

How Do Rep-Based Sets Help You Reach Your Fitness Goals?

Rep-based sets are quite flexible and can be tailored to individual fitness needs. The specific rep range and training volume will depend on the goals, such as muscle hypertrophy, increased muscle strength, or simply improved overall fitness. In general, the lower the repetitions, the more strength is built, and the higher the reps, the more endurance.

How Do Time-Based and Rep-Based Sets Create a Challenge for Your Workouts?

The most effective workouts are the ones that are tailored to the client. Workouts can be easily customized and changed up utilizing both time- and rep-based sets. Using these tools appropriately takes a workout beyond just a stale routine of the same old push-ups.

You can adjust training volume, number of reps or length of sets, and targeted muscle groups to create the entire training picture.

The Primary Benefits of Time-Based Sets versus Rep-Based Sets

Both time-based sets and rep-based sets offer benefits but deliver different results. Interval training, for example, can provide more cardio benefits than resistance training. If you want to focus on modest muscle growth, consistent resistance training may be just the thing.

What Do You Build When You Do Rep-Based Sets?

Repetition-based sets can build both muscular strength and endurance. Generally, low reps (two to six) will build muscle strength. If you want more muscle growth, 6 to 12 repetitions build muscle mass. More than 12 reps build muscular endurance.

What Do You Build When You Do Time-Based Reps?

Building muscle endurance should also be an important part of your training strategy, and time-based sets can do just that. (Of course, you'll need to set a time that will provide an endurance challenge.) Timed sets are also great for cardio.

What Is Meant by Hypertrophy versus Strength Training?

Muscle hypertrophy is all about growing muscle size and mass. This is accomplished by training with less intensity and a moderate number of reps. Both strength and resistance training can increase muscle hypertrophy. Rest periods should last between one and three minutes.

Strength training to build strength can be accomplished by increasing intensity with heavier weights but fewer reps. Take extra time to rest, approximately three to five minutes between sets.

What Is the Principle of Progressive Overload?

Progressive overload is a way to promote maximal strength by gradually and methodically increasing workout intensity. Muscle fibers need to undergo some metabolic stress in order to break down and grow back stronger. Thus, working out consistently with periodic increases in intensity can create the progressive overload that builds strength, muscle, and endurance. Don't forget to plan in some time for strength training recovery!

How to Set Limits for Time-Based and Rep-Based Sets for Your Fitness Training Plan

First, determine the end goal. Do you want increased strength or more muscle mass or both? What about muscular endurance? If you are designing a loaded carry program, then you'll also need to calculate other factors based on the weight being carried.

Why Is It Important to Set Limits for Time-Based and Rep-Based Sets?

Setting the right limits for time-based and rep-based sets is critical for success. Muscle strength and growth may not happen with a haphazard training plan. The right limits help achieve the desired results.

What Factors Determine a Safe Limit for Time-Based or Rep-Based Sets in Your Workout?

Age, fitness level, and overall strength should be considered when determining safe limits for time- or rep-based sets. First, your client should fill out a Physical Activity Readiness Questionnaire (PAR-Q) to identify any counterindications to exercise. Once you have assessed your client's fitness level, you can determine not only the type of workout but the number of repetitions and sets.

For example, an older client with a knee injury may not be up for circuit training or even a slow jump rope workout. However, they might be able to do 10 reps of light weights in various strength training sets targeting specific muscle groups as part of their workout routine.

Each set should challenge the client just enough but not so much that they fail in doing their repetitions.

As noted above, general guidelines for rep-based sets are that fewer reps (two to six) build strength, 6 to 12 reps enhance muscle growth (hypertrophy), and 12 to 15 or more enhance endurance.

How Do You Build Up to Doing More Time-Based or Rep-Based Sets in Your Workout?

Using the principle of progressive overload, you can slowly build up muscular endurance and strength. For example, you might start with six reps at a certain weight and then increase to seven reps at the same weight or six reps at a higher weight. For time-based sets, simply add on to the time in small increments, say 10 seconds.

How Often Should You Change Your Limits for Time-Based and Rep-Based Sets?

The typical time frame for increasing weights or intensity in training is one to three weeks. The key is to maintain a consistent form even when the reps, time, or weights are increased. Thus, if you attempt to increase intensity, but the muscle starts to fail halfway through, back off and return to the previous limit. The RPE scale (rate of perceived exertion) can also be helpful in determining when to increase time, weight, and/or repetitions.

When to Change between Time-Based and Rep-Based Sets in Your Fitness Training

Is it important to change between time-based and rep-based sets in fitness training? Not necessarily. But it depends on what you are trying to accomplish with the workout.

Who Should Consider Changing between Time-Based and Rep-Based Sets in Fitness Training?

It depends. If the main focus is strength training for a specific muscle group, say, with a bench press, time-based sets may not be appropriate at all. But you can mix and match time-based and rep-based sets at any time. Do some rep-based sets with resistance training and then add in a few time-based sets with a jump rope for a cardio workout, for example.

When Is It Time to Change between Time-Based and Rep-Based Sets?

If a client is getting bored with their workout routine, it might be a good time to switch things up from a rep-based workout to timed sets or vice versa. It might also be time to change when results are plateauing, or a new fitness goal is set.

How Often Should You Change between Rep-Based and Time-Based Sets in Fitness Training?

To get the best workout results, be consistent. A regular frequency of workouts will garner the optimal results. And if variety helps the client stay engaged, don't be afraid to mix things up.

Want to Become a Top Personal Trainer?

If you want to get the best results with your clients, the International Sports Science Association (ISSA) can help. We offer best-in-class accredited fitness training programs with convenient online learning to fit your schedule.

Contact ISSA at (800) 545-4772 to learn more about what we offer, and check out our certified personal trainer programs.