|How many exercise sets are best for strength training? © Don Matesz|
Borde et al set out to determine "evidence-based, dose–response relationships regarding specific RT variables (e.g., training period, frequency, intensity, volume) are unclear in healthy old adults."
Their initial literature search identified 506 potentially relevant studies, but their exclusion criteria resulted in a final yield of 25 studies. They included only RCTs that examined the effects of RT in adults with a mean age of 65 and older.
Through meta-analysis of these 25 studies Borde et al found:
"A training period of 50–53 weeks, a training frequency of three sessions per week, a training volume of two to three sets per exercise, seven to nine repetitions per set, a training intensity from 51 to 69 % of the 1RM, a total time under tension [per repetition] of 6.0 s, a rest of 120 s between sets, and a rest of 2.5 s between repetitions turned out to be most effective."The authors however do note:
"Our analyses revealed little or no effect of the training variables “number of sets per exercise” and “number of repetitions per set” on strength gains. The additional analyses of dose–response relationships of the number of sets per exercise revealed an inverse U-shape, with the largest effect (mean SMDbs = 2.99) being prevalent in RT protocols that applied two to three sets. However, it seems that there is no difference between single versus multiple sets in short-term RT (6 weeks) in old adults . Moreover, these results suggested that during the early phase of RT, number of sets was not the primary variable responsible for increases in muscle strength and thickness in old adults ."Thus they suggest that when subjects have no previous training experience, single set training routines produce results substantially equivalent to multi-set routines. However, multi-set routines may be more beneficial in experienced individuals.
This was a meta-analysis so it does not shed light on any mechanisms which might account for their observed dose-response effect of multiple sets in resistance training programs.
Gotshalk et al. reported finding that in comparison to a single-set training program, a multi-set program produced greater post-training increases in lactate, growth hormone (GH), testosterone, and cortisol. Since GH and testosterone both stimulate muscle growth, it may well be that multi-set routines produce greater strength and muscle mass gains on average because they result in greater post-exercise anabolic hormone levels.
The authors suggest that the take home message is that you can make gains with a time-saving single-set training routine, but if you want to maximize results, you may need to utilize a multi-set training routine.
Drew Baye has some important comments to make about these studies claiming superiority of multiple sets. Here are some of Drew's comments:
Most if not all of these studies fail to standardize repetition performance and time under load. With proper repetition performance, a single set training routine can actually involve similar or more time under load and metabolic work stress than a multiple set routine, as Drew explains here:
A slower repetition cadence increases the force generating ability of muscles (due to the force/velocity curve) while increasing the safety of movement. Using a slower repetition cadence a trainee will be able to use a higher training load (resistance) than with a faster cadence. The trained muscles are thus exposed to a higher degree of tension for a similar or greater total time under load when properly performing single-set high intensity training.
Since this meta-analysis is based on studies that did not compare properly performed single-set high intensity training to conventional multi-set training, it does not provide support for the claim that older adults must use multiple set routines to maximize results.