Testing to Identify Submaximal Effort: Lifting to a Perceived 50% Effort vs. an Assigned Submaximal Load

Area of Science:

• Biomechanics
• Occupational Health
• Rehabilitation Science

Background:

• Accurate measurement of effort is crucial for validating physical limitations in post-injury functional testing.
• The Cross-Reference Testing System (XRTS) utilizes distraction-based dynamic material handling to identify submaximal efforts.
• XRTS assesses material handling through crate lifts and lever arm device lifts.

Purpose of the Study:

• To compare the influence of lifting to a perceived 50% effort versus an assigned submaximal load on test results.
• To determine if perceived effort is a valid alternative to assigned loads in functional testing.

Main Methods:

• Two groups performed dynamic material handling tests (crate lift, lever arm lift) at three heights.
• Group A lifted assigned submaximal loads; Group B lifted to a perceived 50% effort (37.5 lb).
• Reproducibility of effort was measured, and a 2x3 ANOVA analyzed differences between groups and lifting heights.

Main Results:

• The mean percent change between comparative lifts was 31.13% for the assigned load group and 29.26% for the perceived effort group.
• A 2x3 ANOVA showed no significant difference (p = 0.751) between the two testing conditions.
• Both methods demonstrated similar reproducibility of effort.

Conclusions:

• Attempting to lift to a perceived 50% effort is not significantly different from attempting to lift to an assigned submaximal load.
• Perceived effort can be a valid method for functional testing in post-injury assessments.
• These findings support the use of perceived effort in distraction-based material handling tests to identify submaximal efforts.