Leg Press Strength Tracking Using the OMNI Resistance Exercise Scale in Older Men and Women

Abstract

Strength tracking uses the OMNI resistance exercise scale (OMNI-RES) as a reference value to determine changes in absolute (i.e. 1-RM) or relative (i.e. %1-RM) strength as a function of a resistance training program. PURPOSE: To determine if the OMNI-RES is valid for tracking leg press strength in older men and women. METHODS: Twenty two males (64.3 ± 3.2 yrs.) and 27 females (63.8 ± 2.8 yrs.) volunteered to participate in this investigation. Participants underwent orientation to determine a pre-training resistance associated with RPEs of 4, 6, 8 and 9 prior to a 12-week resistance training program. Leg press (LP) resistance training consisted of 8–12 repetitions with weights set at 75 % of 1 RM three days a week for twelve weeks as part of a larger investigation. Participants were instructed to perform as many repetitions as possible unless they achieved 12 repetitions. When a participant achieved three sets of 12 repetitions on LP exercise, the weight was increased to a level that allowed only eight repetitions. Linear regression using RPE as the independent variable and percent 1-RM as the dependent variable was used to calculate percent 1-RM at the criterion RPE of 4, 6 and 8. Paired sample t-tests were used to compare pre- and post-training percent 1-RMs at each criterion RPE. RESULTS: 1-RM for LP increased (p= .001) from the orientation trial (90.25 ± 29.76 kg.) to completion of the 12-week resistance exercise (121.81 ± 29.64 kg.). At the criterion RPE of 4, pre-exercise percent of 1-RM was 36.84 ± 11.23 and post training percent of 1-RM was 61.08 ± 14.91. At the criterion RPE of 6, pre-exercise percent of 1-RM was 54.72 ± 10.56 and post training percent of 1 -RM was 74.07 ± 11.14. At the criterion RPE of 8, pre-exercise percent of 1-RM was 72.58 ± 12.22 and post training percent of 1-RM was 86.56 ± 8.43. Percent 1-RM was different (p = .001) from pre- to post-training at each criterion RPE. CONCLUSIONS:To our knowledge, the OMNI-RES has not been used to track strength training responses in older men and women. In the current investigation, at the same level of effort (i.e. RPE 4, 6 and 8), there is a post-training increase in leg press strength based on the percent 1 -RM accomplished. This demonstrates that the OMNI-RES is a valid metric to track training induced changes in muscle strength.