(17) HOW MUCH DOES COACHING LIFTERS FOR MAXIMAL INTENT MATTER? FORCE AND RPE COMPARISONS.

Coaching for maximal force has been understudied and could help support velocity-based training practice. Perception of exertion (RPE) could also be important when comparing intentional coaching instructions. Purpose: To compare intent to exert maximally to uninstructed effort. Also, RPE comparisons between two different isometric strength indices were measured. Demographic characteristics that impact intention were also examined. Methods: Sixty-four college students were recruited for the current study. Two counterbalanced, randomly ordered sessions (4 sessions total) were performed. These included mid-thigh pull and handgrip isometric assessments. After a brief exercise warm-up, one session instructed participants to “pull or grip hard” the mid-thigh isometric dynamometer with force to get an initial reading (Crane Strain Gauge Scale). Then participants were instructed to intentionally give a maximal force “as hard as possible”. These same instructions were given for the isometric handgrip (Jamar handgrip) and two sessions were performed. Counterbalanced, the sessions were randomly assigned based on the participant’s entry into the lab. Performance measures were recorded in pounds for both hand grip and mid-thigh pull and RPE was measured using a category ratio scale of 0-10. Results: When comparing intention versus regular instructions (see Table 1) on mid-thigh pull, a 33.5% difference was observed, and it was statistically significant (p< 0.01) with intention scoring much higher. To a lesser degree, this trend was observed for hand grip, a 27% difference (p< 0.01) again in favor of intention. Related to RPE during the mid-thigh pull, a 21% difference was observed in favor of intention (p < 0.01). This same trend was observed with hand grip, a 37% difference (p< 0.01). A linear regression analysis revealed that sex (men), age, and exercise status (more frequent exercise) accounted for a large portion of variance for the intention mid-thigh pull condition (r²=0.65, F(3, 59)=36.24, p < 0.001) (see Table 2). Conclusions: Intention to exert maximally had a significant effect on isometric strength parameters and perceptions of effort. Intention enhanced strength by 21 to 37%. Moreover, sex and exercise status were the most predictive factors for mid-thigh pull readings during intention of maximal force. These results suggest that men and individuals who exercise regularly demonstrated an enhanced effect of intention to exert maximally. However, perception of effort was less impacted by intent to exert maximally. Practical Applications:  Intention to exert maximal force positively impacted performance from 21-37%. Also, measures on intention to lift maximally were modified by sex and exercise frequency. Perception of effort did not differentiate to forced changes. Coaching to lift with maximal intent could be beneficial to increase force output even if perceptions of exertion are not sensitive enough to detect the magnitude of change in force.

    

Acknowledgements: None