(8) SEX-DIFFERENCES IN COGNITIVE FUNCTION FOLLOWING HIGH-INTENSITY RESISTANCE TRAINING

Purpose: This study examined effects of high-intensity (HI) resistance training on cognitive function (CF) in males and females. Methods: 11 males (age:23.2±3.9yrs; body mass:84.3±12.3kg; height:177.6±8.6cm; upper body 1 repetition maximum(1RM):113.2±21.8kg; 1RM body mass ratio:1.32±0.76; lower body 1RM:151.4±41.6kg; 1RM body mass ratio:1.76±0.57) and 11 females(age:22.5±3.8yrs;body mass:70.1±10.6kg; height:165.1±7.1cm; upper body 1RM:50.8±10.0kg; 1RM body mass ratio:0.73±1.38: lower body 1RM:88.8±19.0kg; 1RM body mass ratio=1.27±0.79) attended two randomized testing visits to determine the impact of high intensity (6 sets of 10 repetitions at 80% 1RM) upper and lower body exercise on CF as determined by NIH Toolbox. Each NIH Toolbox task was examined by, separate 2(Sex:Men vs. Women)x2(Exercise:Upper vs. Lower)x2(Time:Pre-fatigue vs. Post-fatigue) mixed factorial ANOVAs of age-adjusted standardized scores. The maximal voluntary isometric contractions (MVICs) were examined to characterize fatiguability with separate 2(Sex)x2(Time) mixed factorial ANOVAs. Post-hoc Bonferroni pairwise comparisons were utilized with significant (p < 0.05) findings. Results: The ANOVA for the Dimensional Change Card Sort Test (DCCS) demonstrated no significant (sig) interaction (p >0.05) but a sig main effect for Sex (p=0.006, η2p=0.324). Post hoc analysis indicated that female scores (135.56±16.59) were significantly greater than male scores (113.98±16.59; p=0.006). The ANOVA for the Flanker Inhibitory Control and Attention Test (Flanker) demonstrated no sig interaction (p >0.05) but a sig main effect for Sex (p=0.016, η^2_p=0.259). Post hoc analysis indicated female scores (126.11±14.79) were significantly greater than male scores (109.91±15.7; p=0.016). The ANOVA for Pattern Comparison Processing Speed Test (PC) demonstrated a sig Time x Sex interaction (p=0.031, η2p=0.212). For males, pre-fatigue scores (110.77±8.70) were significantly lower than post-fatigue scores (115.40±6.22; p=0.003); there were no sig post hoc findings for the females (p >0.05). The ANOVA for the upper body MVIC demonstrated no sig interaction (p >0.05) but a sig main effect for Sex (p=0.001, η2p=0.449), and Time (p< 0.001, η2p=0.562). The post hoc analysis for sex demonstrated that males (70.76±22.56N·m) were significantly stronger than females (46.05±11.35N·m). The post hoc analysis for Time demonstrated that pre-fatigue values (66.36±24.29N·m) were significantly greater than post-fatigue values (50.45±15.32N·m). The ANOVA for lower body MVIC showed no sig interaction (p >0.05) but a sig main effect for Sex (p=0.039, η2p=0.197) and Time (p< 0.001, η2p=0.562). The post hoc analysis for Sex demonstrated that males (170.52±42.74N·m) were significantly stronger than females (137.76±46.29N·m). The post hoc analysis for Time demonstrated that pre-fatigue (175.3±46.93N·m) was significantly stronger than post-fatigue (132.98±37.29N·m). Conclusions: Upper and lower body exercise elicited muscular fatigue but no modality-specific impact on CF. Males exhibited a fatigue-induced performance improvement in the PC task, while females showed no sig change. Females scored higher on the DCCS and Flanker tasks but had no CF changes post-fatigue. Practical Applications: Under exercise-induced fatigue, CF remained unaffected, with males potentially exhibiting improved processing speed. Practitioners may use skill based or strategic drills with HI training to boost decision-making under fatiguing conditions. Acknowledgements: none