One of the longest running arguments in the history of weight training has to be between those who favour single sets (HIT) and those who advocate multiple sets per exercise. Traditionally the HIT school say that by training a set to failure you end up stimulating all the muscle fibres and once done you should allow your body to recuperate from this stress. So long as strength goes up workout by workout then the HIT school of thought says you will gain muscle at the maximum rate by not over stressing the body’s adaptive capabilities by needlessly performing extra sets.
By contrast the school of thought which advocates multiple sets points out that training is neuromuscular in nature and a single set cannot possibly cause enough muscle breakdown to stimulate an optimal level of muscle gain. By increasing training volume, the body is forced to adapt to the stress of multiple sets by building enough muscle and strength to compensate for the increased workload. The multiple set school argues as well that in no other sport does anyone reach excellence by performing such a low amount of work as the HIT camp advocate. This gives some empirical support to the notion that in elite sport, multiple sets would be superior.
In the past a few studies have attempted to tackle this question with mixed results. Some research shows that single sets can be as effective as performing three sets while others show the benefits being in favour of multiple sets. However, methodological issues with some of these studies makes it difficult to use them to argue in favour of multiple sets as sometimes the multiple set group will be tested on a movement such as a free weight bench press while the single set group had previously trained on a machine version of the exercise. Similarly, examples where the subjects are tested on 1RM allows those performing multiple sets more practice with low reps in some instances as many comparisons of single versus multiple sets are also comparisons of single sets versus a periodised training program that leads into the testing week with workouts gradually reducing in reps which enables the multiple set group to garner more practice on the test.
One thing lacking from the research is an examination of single sets versus more than three sets in a program. Coming from an athletic background three sets would be considered on the low side in terms of volume most athletes practise.
A recent study (1) helps address this issue as it compares those performing 1, 4, and 8 sets of high intensity exercise. The study group assigned 32 individuals randomly to either a one, four or eight set group and were prescribed a routine of training at 80% of their squat 1RM twice a week for six weeks. Following this six week block, the subjects performed a peaking routine for four weeks designed to maximise their strength. At the start, during and at the conclusion of the ten week program, subjects were tested on their squat 1RM, quadriceps muscle activation, and rate of force development (RFD).
The results showed a stark contrast between the groups.
Squat 1RM increased significantly in all groups after 6 and 10 weeks respectively. The 8 set group was significantly stronger than the single set group after three weeks (7.9% difference) and remained stronger through week 6 and 10. Muscle activation did not change through the study while RFD declined over the study in all groups. The study authors concluded that their research shows that more than four sets, eight in this case, leads to greater strength and muscle gains compared to single set training.
This was a very interesting study which, unlike many comparing single and multiple set protocols, used subjects with training experience behind them (6.6 years on average) and a minimum squat of 130kg. This is good because we all know that gains for beginners come much quicker than they do for experienced athletes.
In fact, the training program given was very tough and would be considered quite demanding by most people and in addition to the strength changes the study also looked at body fat readings. These showed that the eight set group gained the most weight while all three groups gained a slight amount of body fat. When we look at the difference between the groups in terms of their strength gains below, we can see the difference between the groups more clearly.
At the outset the 1 set group was weaker than the 4 and 8 set groups. This would normally mean that they had greater room to develop strength and muscle mass than the other two groups so the fact that the 4 and 8 set groups gained more strength from the post washout period lends weight to the notion that high sets are superior. Note that the two week washout where no squats were performed before the study started was designed to ensure all subjects came into the study from a similar training history, eliminating the residual effects of their past training history.
One interesting point was that none of the trainees noticed an increase in muscle activation rates which suggests they were already recruiting the maximum amount of muscle fibres. In addition, a reduction in rate of force development seen during this training suggests this type of strength training is not suitable for promoting power development in athletes. In effect, explosiveness declined during the study which is no surprise given the fact subjects were training to failure which tends to cause CNS fatigue thus limiting explosiveness.
We at Predator have, by and large, advocated multiple set programs for some time and this research certainly supports that view. Having said that, for a program designed for athletic performance there are some problems with the way the exercises were performed, primarily the reliance on training to failure, which if this was modified could likely lead to a more well rounded program that can develop other bio-motor qualities such as speed and explosive strength. Unless trainees have an issue with time which makes single sets superior, we advise that even those who believe themselves to be hard gainers should endeavour to slowly build up their work volume over time.
1. Marshall PW, McEwen M, Robbins DW: Strength and neuromuscular adaptation following one, four, and eight sets of high intensity resistance exercise in trained males.