An Exemplar Frontal Plane Visual Kinematic Stimulus Elicits Sex-Specific Learned Behavior: An Exploratory Report

Abstract

An exemplar frontal plane visual kinematic stimulus elicits sex-specific learned behavior: An exploratory report. J Strength Cond Res 36(3): 857-861, 2022-The purpose of this exploratory study was to determine if a visually delivered kinematic stimulus designed to promote injuryresistant biomechanics would induce sex-specific motor learning effects. Six female subjects and 6 male subjects participated in 2 consecutive day sessions in which they mimicked an avatar performing 5 sets of 8 repetitions of exemplar frontal plane mechanics during single-leg squats. Acute (;10 minutes) and delayed (;24 hours) transfer testing under single-task (single-leg balance) and dual-task conditions (single-leg balance plus cognitive task) were referenced to baseline measurements. Center of pressure (CoP) mean velocity (Vel), SD, and detrended fluctuation analysis (DFA) in the anterior posterior (AP) and medial-lateral (ML) directions were quantified, with dual-task costs defined as the percentage difference from single-task to dual-task. Separate 2 3 3 repeatedmeasures analysis of variance was conducted for each dual-task cost variable. Main effects and interactions with large effect sizes considered as h 2 p $ 0.14 were further explored with pairwise post hoc comparisons. Sex by time interactions were observed for medial-lateral standard deviation cost (h 2 p 5 0.29; p 5 0.04), anterior-posterior standard deviation cost (h 2 p 5 0.27; p 5 0.06), and AP DFA cost (h 2 p 5 0.41; p 5 0.007), in which female subjects displayed lower dual task cost at acute transfer testing compared with male subjects (Cohen's d 5 1.52, 1.64, 0.97; p 5 0.03, 0.02, and 0.13 respectively). This report provides preliminary evidence that female subjects may be more responsive than male subjects to a prescribed frontal plane kinematic visual stimulus. Based on these sex-specific effects, future visually driven stimuli may require alternative strategies to optimize efficacy in male subjects.

Either Autonomy Support or Enhanced Expectancies Delivered Via Virtual-Reality Benefits Frontal-Plane Single-Leg Squatting Kinematics

“…Our primary analysis consisted of three 3x2 repeated measures ANOVAs (between factor: Group [control, AS, EE]; within factor: Time [baseline, post-test]), for measures of peak knee abduction, peak hip adduction, and peak trunk ipsilateral lean. Given the preliminary pilot and proof of concept nature of this study and consistent with similar prior work (Hogg et al, 2022;Williams et al, 2022), we used effect sizes (η p 2 and Cohen's d) to interpret the magnitude of main effects and interactions. We interpreted η p 2 effect sizes as small (.01), moderate (.06), and large (.14) and Cohen's d effect sizes as small (0.2), moderate (0.5) and large (0.8) as according to Cohen (Cohen, 1988).…”

“…We engaged 45 participants (21 male and 24 female) in a single 90-minute research session (Table 1) (Hogg et al, 2022; Williams et al, 2022). Of these, 41 reported prior engagement in moderate-to-vigorous exercise for 30 minutes, three times a week.…”

“…The instrumentation we used for kinematic biofeedback delivery has been reported in detail elsewhere (Hogg et al, 2022; Williams et al, 2022). Briefly, kinematic data for biofeedback delivery were collected using the Microsoft Azure Kinect DK (https://azure.microsoft.com/en-us/services/kinect-dk/).…”

“…We employed a one-day intervention consisting of single leg squats while participants viewed a digital avatar displayed in real-time through a virtual reality headset (Hogg et al, 2022; Williams et al, 2022). The same investigator delivered all interventions in a standardized manner but could not be made unaware of the participant’s allocation to an experimental group and so was not tasked with data reduction or analysis.…”