The Benefit of Lifting in Different Repetition Ranges

Resistance training has been performed as an exercise intervention for muscle growth and strength for well over a century. Early in its inception as a specific and deliberate mode of exercise, it was quickly identified that they were essentially three different loading ranges or repetition zones.

If exercise was performed with loads allowing you to lift between 1 and 5 repetitions, then the primary outcome was increased muscular strength (defined as a muscle's ability to produce force).

If an exercise was performed with sets using more moderate loads, between 8 and 12, then the primary training outcome was an increase in muscle mass.

Finally, if exercises used loads that allowed repetitions to exceed 15, then the primary training outcome would be an increase in strength-endurance.

Since these discoveries over 100 years ago, these 3 repetition zones have been accepted to provide the foundation for goal specific program design, which would broadly have the training outcomes as muscular strength, muscular growth also called hypertrophy or strength endurance.

Only in the last 15 years has the second training outcome, namely hypertrophy, being expanded. Historically, muscle growth was associated with the anabolic hormones that were produced in large amounts when training with moderate loads, in the 8 to 12 repetition range. Exercise scientists, however, through a series of very intricate studies, identified that the hormones produced in exercise had little bearing on muscular adaptation and growth. Rather, studies have found that performing sets with high effort, or close to failure, with multiple sets (higher training volumes), is the primary stimulus to cause muscle growth and not the load or repetition number.

A landmark study, conducted by some of the greatest strength scientists in history, and published in 2002, provided the greatest insight to date on why we use different repetition ranges (which is another way of saying loads), to produce different training outcomes depending on your goals.

The study was conducted over eight weeks and the participants were divided into four groups. The first was a low repetition group, who performed four sets of 3 to 5 repetitions per exercise, resting 3 minutes between sets. The second group was performed exercises in an intermediate repetition range, 3 sets of 9 to 11 repetitions with two minutes rest between sets. The third group performed exercises in a high repetition range, which was 2 sets of 20 to 28 repetitions with one minute rest between sets. The final group was a non-exercising control group. The exercises performed in all three training groups was the leg press, the squat, and the leg extension. This study started with two days of lifting per week for 4 weeks and increased to three days a week for the final four weeks

The researchers investigated the effect of the different repetition ranges on maximal strength, local muscular endurance, various cardiorespiratory parameters, and muscle biopsies were taken analyzed for the muscle fiber composition and cross-sectional area.

The findings of this study showed that maximum strength improved significantly more for the low rep group. Similarly, local muscular endurance improved the most with the high repetition group. Finally, the intermediate repetition group experienced the greatest hypertrophic effect compared to the other training conditions.

This tells us that no one repetition range has the monopoly on muscular adaptations and strength response. That's why progression models have been proposed over 60 years ago to spend time in different repetition ranges, using a variety of loads, over a training year to extract the unique benefits of light, moderate, and heavy loading. 

This is consistent with the principles of training, which dictate that variety in the training stimulus, exercise selection, load, and repetition range are required to avoid stagnation and to ensure constant progression towards one’s goals. You will often hear the statement “the best repetition range for…”, when, in reality, there is no perfect or magical rep range that can do it all. As you have seen, different loads cause different training outcomes, and you will have the best chance of successfully achieve your training outcomes and goals by employing a wide variety of repetition ranges and loads over a training year in a logical and sequential manner.

References

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Folland JP, Williams AG. The adaptations to strength training : morphological and neurological contributions to increased strength. Sports Med. 2007;37(2):145-68. doi: 10.2165/00007256-200737020-00004. PMID: 17241104.

Lopez P, Radaelli R, Taaffe DR, Newton RU, Galvão DA, Trajano GS, Teodoro JL, Kraemer WJ, Häkkinen K, Pinto RS. Resistance Training Load Effects on Muscle Hypertrophy and Strength Gain: Systematic Review and Network Meta-analysis. Med Sci Sports Exerc. 2021 Jun 1;53(6):1206-1216. doi: 10.1249/MSS.0000000000002585. Erratum in: Med Sci Sports Exerc. 2022 Feb 1;54(2):370. doi: 10.1249/MSS.0000000000002838. PMID: 33433148; PMCID: PMC8126497.

Carvalho L, Junior RM, Barreira J, Schoenfeld BJ, Orazem J, Barroso R. Muscle hypertrophy and strength gains after resistance training with different volume-matched loads: a systematic review and meta-analysis. Appl Physiol Nutr Metab. 2022 Apr;47(4):357-368. doi: 10.1139/apnm-2021-0515. Epub 2022 Jan 11. PMID: 35015560.