Resistance-Trained Individuals Can Underestimate the Intensity of the Resistance Training Session: An Analysis Among Sexes, Training Experience, and Exercises

Abstract

Dos Santos, WM, Tavares Junior, AC, Braz, TV, Lopes, CR, Brigatto, FA, and Dos Santos, JW. Resistance-trained individuals can underestimate the intensity of the resistance training session: An analysis among genders, training experience, and exercises. J Strength Cond Res 36(6): 1506–1510, 2022—Resistance training (RT) promotes improvements in healthy parameters for young to elderly adults and athletes' performance. Strength and muscle mass improvements are dependent on exercise intensity. This study verifies whether 53 healthy young adults underestimate exercise intensity in 3 different exercises, such as bench press (BP), biceps curl (BC), and leg press 45° (LP). Researchers asked the subjects “How much load do you use to perform 10 repetitions in this exercise usually in workout routines?” in each exercise. Individuals warmed up and then performed as many repetitions as possible until they reached the concentric failure. Deviations from data normality were found by using Levene's test; the number of repetitions per exercise within sex was tested by using Friedman's test and Conover's post hoc and Kruskal–Wallis tests to compare the number of repetitions between sex and RT experience. We correlated the number of repetitions and training experience using the Spearman test. The number of repetitions for both groups (male and female) is greater than 8–12 repetitions for BC and LP and BP of the female group, except for men who perform around 8–12 repetitions on BP. Frequency of maximal repetitions reached for 8–12 repetitions for women was 12% for BP, 28% for BC, and 28% for LP. The frequency men reached was 46.5% for BP, 14.3% for BC, and 14.3% for LP. Training experience did not influence the number of repetitions reached. Resistance training practitioners underestimate exercise load (56% of total sample) to be independent of experience. Women underestimate exercise load more than men. Based on the present results, it is possible to state that RT should not be prescribed considering a predefined number of repetitions and a linked percentage of loads, without the guidance for frequent adjustments of loads, according to the exercise performed.

Narrative Review of Sex Differences in Muscle Strength, Endurance, Activation, Size, Fiber Type, and Strength Training Participation Rates, Preferences, Motivations, Injuries, and Neuromuscular Adaptations

“…However, on all 5 exercises, men, on average, selected higher relative intensities than women. Dos Santos et al (121) also observed small sex differences in their study. They asked men and women, who had experience with strength training, to select loads that they use in their bench press, biceps curl, and leg press routines for 10 repetitions (121).…”

“…Both men and women tend to select loads between 40 and 60% 1RM. Nevertheless, sex differences are somewhat uncertain because only 2 studies have included both men and women (121,164). Glass and Stanton (164) found that when men and women, who had not participated in strength training experience in the past 6 months, were asked to choose loads sufficient to improve muscle strength for the seated chest press, seated back row, military press, biceps curl, and knee extension, both sexes selected loads equal to 40-60% 1RM across the 5 exercises.…”

Impact of Training Protocols on Lifting Velocity Recovery in Resistance Trained Males and Females

“…Thus, whether the observed differences are due to differences in biological sex or training status is unknown. As a result of the stigmatization of strength training for women, the participation in strength sports and the execution thereof in terms of volume, intensity, and effort may differ between the sexes [32][33][34], leaving training history as an unconsidered variable. This distinction is important as stronger individuals have been observed to be more fatigable [9], and, if individuals possess different abilities at expressing their maximal strength, it will lead to training at differing relative intensities when training is expressed relative to the maximum [11].…”

Toward a New Paradigm in Resistance Training by Means of Velocity Monitoring: A Critical and Challenging Narrative

“…However, different studies have shown that not all subjects can perform the same number of repetitions against a certain relative load [ 7 , 59 , 60 ]. In a recent study [ 61 ] most of the individuals (56.6% of the sample) performed repetitions above those supposedly achievable (e.g., 12RM, 10RM, 8RM), underestimating the prescribed or intended load in all exercises. It thus seems that the prescription of RT should not be based on a predefined number of repetitions since subjects who exercise using the same maximum number of repetitions per set could be training with quite different relative loads.…”

“…If all subjects train with an individually determined absolute load (kg) that allows them to perform the same number of repetitions (e.g., 8RM), it is highly unlikely that they are training with the same relative load (%1RM). This results from the fact that the number of maximum repetitions that can be completed against a certain relative load (%1RM) presents a high inter-subject variability [ 7 , 59 , 61 ]. This problem is not unique to the NPT model, but it is also applicable to any other periodized training model in which the load is applied and quantified using the n RM method.…”