Overload and intensity: why more isn’t always better

Andrew Hamilton explains the concept of overload and intensity for strength training, and presents recent evidence demonstrating that often, less is more…

As a young twenty-something, I remember the bodybuilder who came to train at Nautilus-equipped gym where I was working as a fitness trainer. He mocked the notion that the Nautilus machines were efficient enough to produce a really intense workout with just one set of repetitions per body part, so my colleague cruelly offered this gentleman a complimentary supervised workout on the house as his ‘warm up’, and duly proceeded to work him flat out. Within less than ten minutes, this hulk of a man was reduced to a quivering mass of jelly - which just goes to show that while it’s part of the human condition to assume that if some is good, more isn’t always better!

Achieving resistance goals

Different athletes have different goals when resistance training. Some seek to build general strength and resilience, while others want specific strength gains to help with a sport or activity, or to prevent/recover from injury. But whatever the goal, you can’t escape the basic laws of exercise physiology; specifically, if you want to improve muscle function, you need to generate an ‘overload’ stimulus in that muscle⁽¹⁾, and then allow the process of rest and recovery to take place.

The term ‘overload’ in this context doesn’t mean subjecting to the muscle to harmful and damaging amounts of physical abuse, but it does mean challenging the muscle by asking it to do significantly more work than its current level of conditioning allows for, which then creates a training adaptation⁽²⁾.

For example, if an athlete can habitually and easily perform 8 x repetitions of bench press using a weight of 50kg, going to the gym and performing 8 or 9 repetitions at the same weight to will not produce any real overload stimulus because the athlete’s muscles are already sufficiently conditioned to perform at that level. However, set the same athlete a challenge of performing 12 reps at 50kgs, or maybe 8 reps at 60kgs, and they will generate an overload stimulus in those pectoral muscles, because they’ll be performing significantly more work than they’re used to.

Generating overload

Given that producing overload is the key to producing strength and muscle mass adaptations, the next question is what’s the best way to generate overload? This is where things begin to get interesting because generating overload is not necessarily related to the volume of work performed, or the time spent performing it! Back in the 1950s, a pioneer of resistance training called Arthur Jones – the father of the Nautilus training technique - began asking the same question⁽³⁾. When he delved more deeply into the subject, he soon began to realise that when it comes to resistance training, overload is generated by intensity.

Many athletes remain confused by the concept of intensity in the context of strength training. Intensity is not a measure of how much resistance is used, or even the number of sets/reps that are performed. Intensity is all about packing a lot of high-quality muscular work into a small volume of time. This doesn’t mean running around the gym like a headless chicken, throwing weights around at high speed! What it does mean is that for each muscle group, strength exercises should be performed with enough high quality repetitions and resistance performing in order to properly challenge the target muscle fibers – and that athletes move swiftly between different exercises with minimal rest.

Arthur Jones’ training recipe pioneered a revolutionary new training approach, which emphasized intensity and quality over volume and time. This routine consisted of just one set of strictly executed reps for each major muscle group in the body, performed to ‘failure’ – ie until exhaustion makes it physically impossible to complete another rep without losing form. Trainees would move from one machine to another without resting or pausing, with a complete resistance circuit taking just 12-15 minutes! While Arthur’s superb Nautilus machines played their role in producing great results back in the 1970s and 80s, the principle of intensity is just as valid today as it was then. Unfortunately, many athletes and strength trainers seem to be unaware of its importance, and fewer still put it into practice in the gym

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The three set approach

Let’s analyse a couple of typical resistance protocols employing a typical three sets per body part. A common strategy is to perform three sets of reps using increasing resistance on each set. Although a good approach for injury prevention/rehab (because it allows muscles and tendons to undergo a kind of warm up, it’s more questionable in terms of generating intensity. For example, if you can perform three sets of 8 reps using gradually increasing weights, then by definition, there’s no way you could have reached failure point, or probably even approached it until the final set. Since working to near to or at failure is important for generating intensity, the first two sets (ie two thirds of the volume performed) will have been relatively ineffective.

Another common strategy is to perform three sets at the same weight, but here the same logic applies also. Even if you perform three sets of 8 reps at the same weight, the first and most likely the second set are still relatively ineffective; if you had worked to failure on the earlier sets, there’s no way you’d reach the same number of reps using the same weight in the following set. After you reach failure, or get very close to it, a repeat set demands you reduce the weight or reduce the reps!

But there’s another way the 3 sets of ‘x’ reps approach can lose you intensity. Very up to date research has shown that the neural stimulation that occurs when you train one set of muscle fibers carries over to adjacent fibers in nearby muscle groups⁽⁴⁾. This explains the common ‘cross-talk’ observation that in injured athletes, training the non-injured limb while the injured limb is rested and rehabilitated results in less strength loss in the injured limb than would have otherwise occurred⁽⁵⁾.

Working just one set to failure then moving straight on to an adjacent muscle group means that the secondary stimulus produced in an adjacent muscle group by the first exercise is added to that produced then the muscle group is targeted directly, which produces a greater neural stimulation and intensity overall. Contrast this to the 3-set approach, where any secondary stimulus is limited to the final set (the one before moving to the next exercise), with no secondary stimulus produced by the first two sets.

Evidence

When it comes to maximizing muscle strength and mass in highly motivated athletes with the time and facilities to train, there’s good evidence for performing MORE than one set. In a comprehensive systematic review study published earlier this year, Spanish researchers examined total number of weekly resistance training sets on mass and strength gains in younger trained men⁽⁶⁾. The researchers screened over 2,000 studies and pooled the data from those that met the following criteria:

• Studies that were randomized controlled trials (with the number of sets explicitly reported).
• Studies where interventions lasted at least six weeks.
• Studies where the participants had a minimum of one year of resistance training experience.

They found that 12-20 weekly sets (for the whole body in total) were more effective than 11 or less weekly sets. However, performing more than 20 sets per week resulted in zero additional benefits but did increase fatigue and delayed recovery. Interestingly though, 12-20 sets per week across the whole body (ie shoulders, chest, back, legs, arms) performed over two workouts per week actually amounts to between one and two sets per body part per workout – ie around half of the normally recommended ‘three sets per body part’.

The notion that less can be more is partially backed by bodies such as the American College of Sports Medicine(ACSM). In its guidelines on resistance training, which are based on years of extensive research, the ACSM recommends ‘2-3 sets of 8-12 exercises for each of the main muscle groups in the body’⁽⁷⁾. It also cautions that while additional sets may elicit some additional strength gains, these gains are relatively small magnitude. In plain English, unless you’re already well acclimatized to resistance training or training at a high level, performing more than two sets may be an inefficient use of time.

However, even the ACSM’s 2-3 set guidelines have been questioned by other researchers. In a 2011 paper, researchers proposed a set of scientifically rigorous resistance training guidelines based on a review of the relevant research with the aim of producing more logical, evidence-based training advice⁽⁸⁾. They concluded that: ‘appreciably the same muscular strength and endurance adaptations can be attained by performing a single set of around 8-12 repetitions to momentary muscular failure, at a repetition duration that maintains muscular tension throughout the entire range of motion, for most major muscle groups once or twice each week’ (note the similarity to Arthur Jones’ recommendations!). And a more recent (2020) study also found that a 1-set protocol was as effective as three sets in untrained individuals undergoing a 12-week strength program⁽⁹⁾.

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Does less volume improve adherence?

From the above evidence, it may be possible that performing multiple sets per muscle group could give you the worst of all worlds; not only is someone performing multiple sets is likely to spread out his or her effort across all three sets (which means that the all important intensity generated by reaching or approaching failure is never achieved), but it may also result in poorer adherence to a strength program. This might not be surprising – at the end of a long day at work, the thought of an hour or more strength training at the gym is far less appealing than a quick 20-minute blast! And it turns out that research seems to confirm this notion too.

In a study carried out earlier this year by a team of Aussie scientists, researchers sought to identify the minimal-dose resistance training for improving muscle mass, strength, and function⁽¹⁰⁾. The researchers concluded that ‘there is accumulating evidence suggesting that minimal doses of resistance training characterised by lower session volumes than in traditional recommendations can improve strength and functional ability in younger and older adults’. They also concluded that ‘compared to traditional approaches, minimal-dose RT may also limit negative affective responses, such as increased discomfort and lowered enjoyment, both of which are associated with higher training volumes and may negatively influence exercise adherence’.

Lower vs. upper body

A final point to add is that the number of sets required to generate intensity and produce a good training adaptation may depend on the muscle group being trained. In particular, there appears to be a different response to training in the upper and lower body. A study by Norwegian researchers on this topic found that 1-set training over six weeks was equally effective as 3-set training for the upper body (eg bench press for chest, pull ups for back etc) but that 3-set training was more effective in producing strength gains for the lower body (eg leg press, squats etc.)⁽¹¹⁾. These findings were duplicated in a later study that compared 1 and 3-set training over a period of 11 weeks So it may be that upper body muscles have a lower ‘stimulus threshold’ than those of the lower body⁽¹²⁾.

Conclusions and practical advice for athletes

Let’s pull all these strands together, and put together some guidelines for athletes seeking maximum strength bang for their training buck:

• Where maximum strength is the goal, and where the athlete is already highly strength trained with ample time to train and recover, a multi-set approach is still likely to produce the best results. However, this assumes that no more than three sets per body part are performed per workout and that all the sets are of high quality of movement and intensity.
• Bearing in mind the above, there’s little evidence to suggest performing more than 20 sets per week in total generates significant extra gains.
• Novice athletes and those who are tight for time may derive most of the benefits of strength training by performing just one, or at most two sets per muscle group – providing those sets are performed to near or actual muscle failure, have a full range of motion and maintain muscle tension throughout the movement.
• In circumstances where there is very limited time for strength training, performing just one set of reps to near or actual failure can still produce excellent results in those who are not already highly strength trained.
• When considering how to allocate sets, the evidence suggests that the upper body is most amenable to 1-set training, whereas the legs may require more than one set. Athletes with limited time resources could therefore adopt a mixed approach – ie 1-set training for chest, back and shoulders but 2-set training for the legs.

References

1. Am J Physiol Med. 1979; 58: 115-130
2. J Strength Cond Res. 2017; 31: 1362-1370
3. en.wikipedia.org/wiki/Arthur_Jones_(inventor)
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7. 'ACSM Guidelines for Strength Training' download resource; Jul 31, 2019. Fiataraone Singh, Maria; Hackett, Daniel; Schoenfeld, Brad; Vincent, Heather K.; Wescott, Wayne
8. Medicina Sportiva September 2011. 15:147-162
9. Clin Exp Hypertens. 2021 Feb 17;43(2):164-168
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11. J Strength Cond Res. 2003 Feb;17(1):115-20
12. J Strength Cond Res. 2007 Feb;21(1):157-63