Minimum Effective Dose Training For Strength & Size

Evidence is clear that strength training increases muscle strength and size, and provides numerous other positive health benefits, including improved functional ability, cardio-metabolic risk profile and well-being.

Therefore, strength training is highly recommended as an interventional strategy for the general population.

Despite this clear evidence, the majority of people do not perform strength training and other forms of exercise, and many people in the world are at risk for developing health-related problems and diseases linked to inactivity.¹

It is absolutely imperative to find ways to engage more people in both daily-life physical activities and regimented forms of exercise such as strength training.

Probably the most common self-reported barrier to engaging in structured exercise is lack of time.² 

This means that gaining a clear understanding on how strength training programs can be designed in ways that reduce training time without meaningfully compromising results could inspire more people to participate in this crucial form of exercise.

Below I will synthesize the evidence as to how strength training can be programmed for optimum time-efficiency.

This review is geared towards the general public that have limited time for exercise and not athletes who are seeking to optimize training adaptations without too much concern for the time commitment. 

Training frequency and volume

Training frequency and training volume are arguably the most important variables related to training time. Emerging evidence indicates that it’s possible to achieve similar training effects by training once a week compared to higher frequency when total weekly volume is equal.³ 

As long as training volume is matched (i.e., total number of repetitions (sets x repetitions) or as total volume loading (sets x repetitions x loads), no significant effect of training frequency was observed for strength or muscle size gains. 

Therefore, working a muscle 1 day per week appears to induce similar strength gains as training ≥ 3 times per week if total training volume is the same. 

One feasible alternative for individuals reluctant to schedule longer training sessions is “micro dosing” which are frequent training sessions of very short duration (e.g. 15 min). Research shows that these micro workouts are similar to the adaptations attained from traditional programs since total weekly volume is the primary factor.⁴

As far as looking at the minimal effective dose, there are studies that show performing only a single set three times per week is effective for increasing strength and muscle size.⁵ 

This can especially be beneficial for novice trainees and older individuals.

Although the effect was suboptimal in resistance-trained individuals, performing a single set of 6–12 repetitions, using 70–85% of 1 repetition maximum (RM) loading, for two to three times per week was identified as the minimum effective training dose to increase 1-RM strength.⁶

Although a high training volume appears superior to maximize muscular adaptations, it is possible to improve both strength and muscle size when training with a relatively low number of weekly sets (less than  5 sets).

However,  less than  5 weekly sets can refer to anything from 1 to 4 sets and considering that there still is a lack of consensus regarding this metric, it’s recommended to perform at least 4 weekly sets per muscle.⁷ 

Higher training volumes should be determined based on individual response, taking into account whether the additional time expenditure is worth the potential additive increases in muscular adaptations. 

Training Load and Repetitions

Previous research suggests that training load, typically defined as target repetition number to muscular failure (e.g., 12 RM) or as a percentage of the one repetition maximum (% of 1 RM)—is the most important variable in strength training.⁸ 

Guidelines from the American College of Sports Medicine (ACSM) recommend people in general train within a 1–12 RM loading range with emphasis on the 6–12 RM range to improve muscle strength and size, with lighter loads (15–25 RM) suggested for increasing muscular endurance.⁹ 

However, emerging evidence indicates that similar muscle growth responses occur across a wide spectrum of repetition ranges (even when using very light weights) as long as the training is performed with a high level of effort and the number of sets is equal.¹⁰ 

One important note is that in resistance-trained individuals, heavy loads appear to be more important for strength gains.¹¹ 

With limited training time heavier loads may be preferable, and it seems reasonable to emphasize the 6–12 RM range as recommended by the ACSM as a vast body of evidence indicates that this loading zone is very effective for increasing both maximal strength and hypertrophy.

However, low-load training provides a time-efficient alternative for home-based training and also represents a viable alternative to heavy-load training for those with joint-related issues (e.g., osteoarthritis, etc.).⁷

Exercise selection

If seeking time-efficiency in your workouts, one should prioritize multi-joint exercises as the greater amount of muscle mass trained allows for shorter training sessions despite the somewhat longer recovery needed between sets to accommodate the higher levels of exertion.

Essentially, training with a barbell allows for a higher total muscle activation and an ability to lift heavier weights compared to dumbbells.

While dumbbell exercises can be good for targeting specific muscles, and provide a freer range of motion which in some cases can be desirable, it would seem that training with a barbell is the more time-efficient option.

When deciding as to whether barbells should be prioritized over machines one would need to take several factors into account (e.g. available equipment, lifting experience or the availability of competent instructors).  

It's recommended that bilateral exercises (training both sides of the body at the same time, e.g., squat or barbell curl) are more time-efficient and thus should be prioritized unless core-activation is central to a person’s training goal.

Unilateral training (training one side of the body at a time, such as a split squat or dumbbell curl) is a viable option to increase the difficulty of an exercise in situations where less weight is available, such as during home-based training.

Consideration of other training variables

Muscle action

Muscle actions can be categorized into concentric (shortening of the muscle), eccentric (lengthening of the muscle), and isometric (no change in muscle length). There are some advantages of isolating each of the muscle actions, however, most strength training exercises, and human motion in general is comprised of both concentric and eccentric muscle actions, and optimal training responses rely on training both.¹² 

Therefore, dynamic muscle actions combining concentric-eccentric movements should be utilized for time-efficiency.

Repetition velocity

Repetition velocity (or repetition tempo) is operationally defined as the time it takes to perform the concentric and eccentric muscle actions. 

It has been suggested that increasing time under tension by utilizing very slow (10 sec concentric: 4 sec eccentric) movements can result in higher muscle growth responses when training with submaximal loadings,¹³ and several popular science articles and internet forums advocate training with increased time under tension for muscle growth.

A 2015 meta-analysis found that when training is performed to failure, it is unlikely that one particular repetition velocity will result in greater muscle gains than another, as it was found that repetition durations (combined concentric and eccentric) ranging from 0.5 to 8 seconds resulted in similar muscle growth.¹⁴

In summary, a wide range of repetition velocities can be utilized to induce muscular adaptations, and manipulation of this variable is unlikely to markedly influence changes in muscle growth.

As a general rule, a somewhat faster repetition cadence should be employed when time is of the essence since faster velocities tend to be more time-efficient than slower velocities.

Moreover, volitional fast velocities may be preferable for improving strength and power, and super-slow velocities (≥ 10 sec) should generally be avoided for strength, power or hypertrophy.

Rest periods

The need to rest between sets is often a frustrating requirement for people with limited time to train. However, adequate rest between sets is considered a crucial program variable for optimizing gains in strength and muscle size.

The interset rest period allows the body to remove lactic acid, and replenish adenosine triphosphate and phosphocreatine—i.e. organic chemicals important for muscular contraction. Insufficient rest can result in a reduced capacity to maintain high muscular force throughout multiple sets and a lowered training volume load (load × repetitions × sets), which is considered important for improving both muscle growth and strength.¹⁵ 

Recommendations are that untrained individuals schedule 1–2 min rest intervals and trained individuals ≥ 2 min rest intervals.

Advanced Time-saving training methods

Superset training

Superset training has grown in popularity despite limited supporting scientific evidence on the topic. Superset training (also known as paired-sets training or compound sets) is when two or more exercises are performed in succession with limited or no rest between them/  A 2010 review suggested supersetting exercises for agonist and antagonist muscles is a time-efficient alternative to traditional strength training.¹⁶ 

Other research supports the idea that, when training to failure at an 8-12 RM loading scheme, superset training can be performed in approximately half the time as traditional training without compromising training volume.¹⁷ 

All these studies involved supersets that paired exercises for agonists and antagonist muscles.

Drop set training

In drop-set training, training time is reduced by minimizing rest between sets. The strategy involves performing a traditional set, reducing the load, and then immediately performing another set (or multiple sets).

Typically, 1–3 drops are used with a 20–25% reduction in weight, with all sets performed to muscular failure. 

A proposed rationale behind this method is that drop-sets elicit a larger metabolic stress and potentially heightened muscle damage, which in turn could increase the muscle growth response.¹⁸

Despite the limited evidence, drop-set training seems to allow for shorter duration workouts with little or no reductions in training volume or training responses (especially muscle size increase), thus making it a viable training method for those who are time-pressed to train.

It should also be noted that most of the studies on the topic were carried out using single joint, upper-body exercises. While drop sets can be used for both single-joint and multi-joint exercises, the strategy is most suited to single-joint training from a practical perspective.¹⁹ 

Due to safety concerns, it might not be advisable to include drop-sets in certain compound, free-weight exercises such as squats.

Rest-Pause Training

Rest-pause training is a method of structuring sets where normal interset rest periods are accompanied by preplanned rest within the training sets.²⁰

During rest-pause training, sets are segmented into smaller sets with short breaks in between.

These are commonly performed in one of two ways:

1. The first approach involves performing 4–6 sets of single repetitions using a load close to 1RM.
2. The second approach involves performing one set to failure interset rest (often 20 sec), new set to failure interset rest, etc., until the preplanned number of repetitions are performed.²⁰

The level of evidence for the rest-pause method remains equivocal, and more research is needed to draw firm conclusions as to its effects on muscular adaptations. Still, when time is a barrier to training, rest-pause training appears to be an efficient method for improving both strength and especially muscle size increases.

It’s important to note that the rest-pause method of training is very intense, and some training experience is probably required to train this way in a safe manner, especially when performing complex multi-joint, free-weight exercises.

See table below for a summary of practical applications for time-efficient strength- and hypertrophy programs (adapted from Iversen et al, 2021 ⁷)

Summary

Understanding how training variables such as time, frequency, and intensity can be manipulated and how specific training techniques can be used to optimize the training response is important, especially for people with limited time to train.

Individuals with very limited time for resistance training should aim to train with  more than 4 weekly sets per muscle group using a 6–15 RM loading range.

If training is performed to volitional failure, a 15–40 repetitions range can also be employed. 

By performing bilateral, multi-joint exercises, all major muscle-groups can be targeted with as few as three exercises (i.e., a leg pressing exercise, an upper-body pushing exercise, and an upper-body pulling exercise: e.g., leg press, bench press and seated rows). 

You can train in one, or several shorter sessions—whatever suits the individual. Additionally, advanced training techniques such as drop-sets, rest-pause training and supersets can be used to increase training volume in a more time-efficient fashion.

To further reduce training time, individuals could abstain from stretching and a general warm-up, and limit the specific warm-up to the first exercise for each muscle group.

References

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