Resistance Training And The Effect Of Load Blinding In Multiple Repetition Maximum Tests

Purpose: To compare performance in successive 1-repetition maximum (1RM) tests with the load known or unknown. Methods: Thirty-two resistance-trained men were randomly divided into 2 groups: load blinding (BLI; n =16; age 28.1 [6.9] y, body mass 83.1 [11.5] kg, height 175.3 [5.8] cm) and load nonblinding (nBLI; n= 16; age 27.7 [4.1] y, body mass 83.2 [12.8] kg, height 178.7 [7.3] cm). The groups performed a 1RM test during 4 days (with an interval of 24-48 h) in the horizontal bench press with free weight. Results: In the BLI, there were no significant changes throughout the tests, with a difference of 1.6% between the first and fourth 1RM tests. In the nBLI, there was a significant interaction with time, and the values of the second (P= .03), third (P= .02), and fourth (P = .01) tests were higher than the first test; in addition, the fourth test was significantly higher than the second test (P = .02). The percentage difference between the last and first 1RM tests was 7.1%. The comparison between the groups demonstrated differences in the third (P= .04) and fourth (P= .02) tests with higher values in the nBLI. The intraclass correlation coefficient between the first and fourth 1RM tests was .93 for the BLI and .91 for the nBLI. Conclusion: BLI does not influence 1RM testing in the bench press exercise.