One popular fullbody barbell strength training program prescribes 3 set (x 5 reps) 3 times a week. Another one prescribes 5 set (x 5 reps) 3 times a week.
In order to save time, thinking that volume was the important factor, I have trained 5 sets twice a week.
I was surprised to find this study that found that performing only 1 set each workout resulted in less hypertrophy but equal or greater strength than performing 3 or 5 sets. The increases in strength are large for a 8 weeks study, especially for the squat. This seem to indicate that they were not trained in the squat before the study. The change in strength does not increase with volume as one would expect. On the other hand it does not decrease with volume either. This seems to indicate that overtraining was not the cause for this curious result. One possible explanation I can come up with is this: benchpress and squat has a large component of skill. The increases we see in strength in this study is mainly due to improvement in this skill. It is limited how much the brain can improve in this skill per workout. If this is the case the whole study becomes pretty worthless with respect to strength.
Also note that 8-12 reps was used. They mention that "it seems likely that training in more of a powerlifting range (3-5 reps) would necessitate the performance of more sets to maximize strength". Sadly this was not tested.
Another possible more general explanation is that hypertrophy is dependent on total volume, whereas strength is dependent on the total number of workouts per week once a minimum effective dosage (volume) is met.
Is this correct? Are there other studies that collaborate or contradict this?
If so I am thinking I am better off doing 2-3 sets 3 times a week than doing 5 sets twice a week.
The forementioned study seem to collaborate the old notion that bodybuilders are weak but "bloated". Greg Nuckols seem to disagree with this: Powerlifters Should Train More Like Bodybuilders.
In another article he mentions that "Early on in training, there’s a very weak relationship between gains in muscle and gains in strength". This confirms what we see in the study above.
Furthermore: "For more experienced lifters, gains in muscle mass may explain up to 65%+ of the variability in strength gains, highlighting hypertrophy as a key factor for strength gains in trained lifters".