Traditional strength training with 80% of one-repetition maximum (1RM) utilizes 2- to 5-minute rest periods between sets. These long rest periods minimize decreases in volume and intensity, but result in long workouts. Performing upper-body exercises during lower-body rest intervals may decrease workout duration, but may affect workout performance. Therefore, the purpose of this study was to compare the effects of traditional vs. alternating whole body strength training on squat performance. Twenty male (24 +/- 2 y) volunteers performed two workouts. The traditional set workout (TS) consisted of four sets of squats at 80% of 1RM on a force plate with 3-minutes rest between sets. The alternating set workout (AS) also consisted of four sets of squats at 80% of 1RM but with bench press, and bench pull exercises performed between squat sets 1, 2 & 3 with between-exercise rest of 50 seconds, resulting in approximately 3-minutes rest between squat sets. Sets 1-3 were performed for four repetitions, while set four was performed to concentric failure. Total number of completed repetitions of the fourth squat set to failure was recorded. Peak ground reaction force (GRF), peak power, (PP), and average power (AP) of every squat repetition were recorded and averaged for each set. There was no significant interaction for GRF, PP, or AP. However, volume-equated AP was greater during the TS condition (989 +/- 183) than the AS condition (937 +/- 176). During the fourth squat set, the TS condition resulted in more reps to failure (7.5 +/- 2.2) than the AS condition (6.5 +/- 2.2). Therefore, individuals who aim to optimize squat AP should refrain from performing more than three AS sets per exercise. Likewise, those who aim to maximize squat repetitions to failure should refrain from performing upper body multi-joint exercises during squat rest intervals.
Alex’s Notes: Time is a major barrier to engaging in exercise. Even in those of us who are dedicated physical culturists, time gets in the way every so often. Traditional strength training workouts utilize multiple sets with sometimes quite long rest periods that can make a workout take up a good chunk of the day. To get around this, most people (myself included) utilize supersets or circuit training to get through more exercises with less time spent standing around. Although the workout time may be significantly shortened, research suggests that exercise performance is unaffected. However, this and other studies either used single-joint exercises or multiple-joint exercises that didn’t recruit a large amount of muscle mass. Thus, the current study sought to compare alternating (AS) the three most common lifts – the back squat, the bench press, and a row – with traditional strength (TS) training.
The subjects recruited had all participated in a minimal average of three resistance training workouts per week over the past year and could back squat 1.5 times their body weight. Not advanced by any means, but definitely representative of the average intermediate trainee. They all completed two workouts in a week that were separated by at least 48 hours and performed at the same time of day. The TS protocol consisted of four sets of squats at 80% 1RM (correlates to about an 8RM) with 3-minute rest intervals between sets. The AS protocol was the same, except that the bench press and bench pull were performed (also at 80% 1RM) between squat sets in an alternating manner with about 50 seconds of rest between sets so that the rest between squats was still roughly three minutes. Importantly, all exercises were performed for four reps for sets 1-3 and taken to failure for the fourth set.
This is actually a large flaw in my opinion. It is very unlikely that people would use their 8RM weight for only four repetitions during their workouts. The amount of generated fatigue likely wasn’t as great as it would have been if the subjects had stopped 1-2 reps short of failure like most lifters do. This likely also explains why the TS was only able to perform one additional repetition during the fourth set to failure compared to the AS group (7 vs 6 reps, respectively). There was also considerable inter-subject variability with only 60% of the subjects exhibiting fewer repetitions during the AS protocol, suggesting that individual differences in metabolite buffering capacity and recovery ability influence performance during AS training. Regardless, even with the inferior set-up of stopping at 4 reps with an 8RM weight, alternating upperbody exercises with the squat reduces squat performance, and this likely would have been more pronounced if the subjects went 1-2 reps short of failure on sets 1-3.
Accordingly, both an accumulation of central and peripheral fatigue was likely the reason. Doing a bench press or row may have decreased blood flow to the leg muscles, and thus reduced metabolite clearance. However, since cardiac output probably also increased in that group, more blood would have been delivered to all muscles of the body anyways. But the upperbody work must have still generated more metabolites whereas the TS protocol gave time for their clearance. So basically, you aren’t giving your cardiorespiratory system a break and generating more metabolites. Peripheral fatigue seems reasonable. As for central fatigue, studies have demonstrated that fatigue to exercised muscle impairs their neural drive, but no studies have noted how neural drive changes for the non-exercised muscles. Thus it seems unlikely that upperbody work impairs neural drive to the squats, but the increased peripheral fatigue may have fatigued the legs more and thus reduced their own neural drive.
On a final note, the squat isn’t really just a leg exercise. It works the core musculature, the shoulders, and pretty much the entire body. The degree of which would depend on the absolute load used on the squat, with more experienced lifters using heavier loads and thus using more of their body. For these individuals, it appears prudent that if you squat you should focus on the squat. This may even extend to the intermediate lifters that wish to maximize squat performance. However, if you don’t need to maximize squat performance and are short on time, or using a relatively lighter load on the squat, then alternating with an upperbody exercise may shave a rep off the last set, but nothing too concerning.