Author(s): BOTTURA, R., PANASCÌ, M., ANDINA, G., RUGGERI, P., FAELLI, E., BISIO, A., Institution: UNIVERSITA DEGLI STUDI DI VERONA, Country: ITALY, Abstract-ID: 1938

INTRODUCTION:
Motor imagery (MI) has been proposed as a strategy to enhance motor control and movement efficiency. However, evidence regarding its acute effects on running biomechanics remains limited. This study aimed to investigate the acute impact of a MI intervention on biomechanical responses during a time-to-exhaustion running test.
METHODS:
Twenty-eight active university students with previous treadmill running experience were randomly assigned to either an MI group or a control group (CONTR) and then performed an incremental cardiopulmonary exercise test (CPET) to determine the velocity at the secondary threshold (vVT2). Seventy-two hours later each participant completed a time-to-exhaustion running test (TTE) at vVT2. Prior to the TTE, the MI group performed a guided imagery protocol focused on running technique (i.e., reducing vertical oscillation and increasing stride length), whereas the CONTR group read a short scientific summary about the influence of biomechanics on running economy. Biomechanical variables were recorded using a Garmin Running Dynamics Pod on both tests. In both tests, group differences were first examined using multivariate generalized linear model (GLM) with cadence, ground contact time, stride length, vertical oscillation, and vertical ratio (obtained as vertical oscillation / stride length) as dependent variables, and speed as covariate (the latter only for the time-to-exhaustion test). Time to exhaustion in the two groups were compared by means of univariate ANOVA. Subsequently, a hierarchical linear regression model was applied to investigate factors associated with changes in vertical ratio.
RESULTS:
On both tests, the multivariate GLM revealed no significant global effects of group on the overall set of biomechanical variables (p > 0.05). However, univariate analyses on the time-to-exhaustion test showed significant group differences in vertical ratio (p=0.032), with lower values observed in the MI (7.32±1.18 %) compared to the CONTR (8.68±1.77 %) group. Time to exhaustion was longer in the MI group (14:30 ± 6:12 min:s) compared to the CONTR group (vs. 13:55 ± 4:23 min:s), although the difference did not reach statistical significance. Hierarchical regression analysis indicated that group explained approximately 18% of the variance in vertical ratio (ΔR² = 0.184, p = 0.029), while speed (p = 0.820) did not contribute significantly.
CONCLUSION:
Our results showed that, in active university students, a single session of MI induced small but significant acute changes in vertical ratio. This result suggests that MI may represent a complementary strategy to promote immediate modulation of running techniques.