Research Spotlight: Do people prefer being told what to do in the gym?

Research Spotlight articles share concise breakdowns of interesting studies. The study reviewed is "Exploring the Acute Affective Responses to Resistance Training: A Comparison of the Predetermined and the Estimated Repetitions to Failure Approaches" by Schwartz et al. (2021)

We’re pretty big fans of autoregulation generally, and autoregulation employing reps in reserve (RIR) in particular. However, RIR-based autoregulation approaches may not be appropriate for everyone. For example, if someone simply isn’t good at estimating how many reps they have in the tank near the end of a set, they probably won’t benefit from RIR-based autoregulation. Furthermore, it’s important to take preferences into account when designing a training program, which begs the question: do people actually enjoy RIR-based autoregulation?

In a recent study, 20 women with “extensive Pilates experience but without [resistance training] experience” completed a standardized workout under two conditions. In one condition, subjects completed a predetermined training prescription (3 sets of 10 reps with 70% of 1RM) for each exercise; in the other condition, subjects terminated each set when they felt they were two reps away from concentric failure (3 sets at 70% with 2 RIR). The exercises performed were leg press, knee extensions, pull-downs, and machine chest press. Before and after each set, the participants rated their affective valence using the Feeling Scale, where 5 denotes feeling “very good,” 0 denotes feeling “neutral,” and -5 denotes feeling “very bad.”

On average, participants enjoyed the predetermined training prescription slightly more than the RIR-based approach (p = 0.006). The Feeling Scale score was 3.29 ± 0.89 in the predetermined condition, and 3.01 ± 0.95 in the RIR-based condition (Figure 1). Overall, 12 subjects preferred the predetermined training prescription, and eight preferred the RIR-based training prescription.

The researchers also recorded the number of reps completed per set in the RIR-based condition. On average, subjects wound up performing 8-9 reps per set of knee extensions, chest press, and pull-downs in the RIR-based workout, and about 17 reps per set of leg press. There was considerable individual variability about those averages, as you can see in Figure 2. Finally, the subjects provided subjective descriptions of why they preferred either the predetermined training prescription or the RIR-based training prescription; you can see some examples of that feedback in Table 1.

Training prescription involves a balancing act between designing the sort of program you (or your clients) will enjoy, and designing the sort of program that will provide the training stimulus you (or your clients) need. This study suggests that people generally enjoy resistance training (which confirms my biases, so it must be true), as evidenced by nearly unanimous positive Feeling Scale ratings with both styles of training prescription. However, some individuals had clear preferences for either predetermined training prescriptions or RIR-based training prescriptions. For example, one individual had a leg press Feeling Scale rating of 4.5 with a predetermined training prescription, and a Feeling Scale rating of just 1 with an RIR-based prescription. Conversely, one individual had a knee extension Feeling Scale rating of 0 with a predetermined training prescription, and a Feeling Scale rating of 2.5 with an RIR-based prescription. For most individuals, the difference between conditions was less than 1 point on the Feeling Scale, meaning that both methods of training prescription were similarly enjoyable.

We’ve discussed the benefits of RIR-based autoregulation pretty frequently in MASS, and the data from this study strongly illustrates one of those benefits: when you’re assigning training loads using percentages of 1RM, one-size-fits-all rep targets may be unrealistic, because strength endurance can vary so widely between individuals. A rep target that’s appropriate for one individual may leave another individual 10 reps from failure. With RIR-based autoregulation, on the other hand, most folks will wind up at an appropriate proximity from failure. However, if someone isn’t good at assessing their reps in reserve (which does improve with experience), or if they simply prefer a predetermined training prescription, you can certainly make a predetermined training prescription work by either personalizing training intensities (if you want people to train in a particular rep range, you’d have people with better strength endurance train at a slightly higher intensity than people with worse strength endurance) or personalizing rep targets (if you want people to train at a particular intensity, you’d assign higher rep ranges to people with better strength endurance).

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