Lifting with spotters isn’t just a good idea for safety. Spotters can also improve performance.
In a 2017 study by Sheridan and colleagues, recreationally trained lifters completed two sessions consisting of three sets of Smith machine bench press to failure at 60% of 1RM. In one of the sessions, subjects could see that they had spotters. In the other session, spotters were obscured behind opaque barriers (a Smith machine was used so that a perfectly linear bar path would allow for the use of the barriers, and so lifters could easily re-rack the bar themselves if they couldn’t complete a rep). The subjects were told that the point of the barriers was to see if people would perform better with fewer distractions. When the spotters were present, they were silent.
Subjects completed an average of ~1.5 additional reps per set when the spotters were visible. This observation was very consistent; one subject completed the same number of reps in both conditions, and all other subjects completed more total reps when the spotters were visible. The subjects also reported higher self-efficacy when the spotters were visible. Additionally, even though the subjects completed more reps, effort-based ratings of perceived exertion were a bit lower when spotters were visible.
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The authors propose that the presence of spotters improved performance via social facilitation effects. In practice, the presence of spotters may have an even larger effect than was observed in this study. The spotters in the Sheridan study were silent; in the real world, spotters are generally vocally encouraging, which has independently been shown to improve force output in other research.
In general, I think it’s a good idea to have a training partner (or several partners) for spotting and encouragement when training. However, even if you prefer training without a partner, asking for a spot when you’re lifting has the potential to not only increase safety, but also improve your training performance.
This study was reviewed in more depth in Volume 1, Issue 9 of MASS.