Type of Encouragement Influences Peak Muscle Force in College-Age Women

Abstract

To investigate if the type of encouragement during a maximal voluntary isometric contraction (MVIC) had an influence on peak muscle force in strength-trained versus untrained collegiate women. Eleven strength-trained (20±1 y) and twelve untrained (21±1 y) women participated in three, five-second MVICs of seated knee extension. The three trials consisted of verbal only encouragement, verbal + visual encouragement, and verbal + pain avoidance encouragement. In all three trials, the participants received the same verbal encouragement. Trials were counterbalanced to minimize any possible order effects. A repeated measure ANOVA was used to analyze data. Any significant main effects were further analyzed using Tukey post hoc tests. There was no interaction between training status and encouragement type for all subjects F(2,42) = 1.5474, p = 0.22). For all subjects, a main effect for encouragement type was detected (F(2,42) = 6.616, p <0.05) with significant differences found in MVIC between the verbal encouragement and verbal + visual feedback (99.5±29 ft-lbs and 115.6±29 ft-lbs, p<0.01). No significant differences were found between the verbal only and the addition of pain avoidance (99.5±29 ft-lbs and 109.9±26.3 ft-lbs, p=0.069) or the visual and pain avoidance trials (115.6±29 ft-lbs and 109.9±26 ft-lbs, p=0.43). In this study, training status did not significantly influence the response to type of encouragement. Individuals produced the most force during a MVIC with verbal and visual encouragement. The incorporation of verbal encouragement and visual feedback is an important factor in eliciting peak force in college-aged women. This may have important implications in training and rehabilitation models that incorporate resistive loading of the skeletal muscles.

Keywords: Central Activation Ratio; Electrical Stimulation; Resistance Training.

Figure 1

Maximal voluntary isometric contraction (MVIC) force output during knee extension for all participants (n=23). Verbal, verbal encouragement only, Verbal + Visual, verbal and visual encouragement, Verbal + PA, verbal and pain avoidance (PA) encouragement. *Significantly different from Verbal, P<0.05.