Anchoring and Postural Stability

Summary

This study will compare standing balance in adults ages 18 to 50 during normal standing, inward anchoring, and outward anchoring. Anchoring involves standing with the feet wider than shoulder width and trying to pull the legs together or push them apart without moving the feet. Participants will complete all three conditions in a randomly assigned order. A researcher will use a handheld force-measuring instrument at six points on the pelvis to measure how much pressure participants can resist before a foot lifts from the floor. Participants will also rate how stable they feel after each anchoring condition. The first 18 participants will repeat assessments to evaluate measurement consistency. Participation is expected to last 60 minutes, or 90 minutes for those completing repeat assessments.

Detailed Description

The study will enroll 72 adults from the University of Central Florida community. Participants will be randomized with equal probability to one of six counterbalanced orders of normal stance, inward anchoring, and outward anchoring. Every participant will complete all three conditions. Inward anchoring involves attempting to draw the legs toward one another without moving the feet. Outward anchoring involves attempting to press the legs away from one another without moving the feet. Both anchoring conditions use a stance wider than shoulder width. Participants will wear their usual athletic footwear. The same tester will apply a microFET2 handheld dynamometer at the right and left anterior superior iliac spines, iliac crests, and posterior superior iliac spines. Applied pressure will increase until the sole of the foot closest to the tester leaves the floor, at which point force will be recorded in newtons. Each site will be tested three times in each stance. Rest periods will be one minute between sets within a stance and two minutes between stances. Instructions for the next stance will be given during the final minute of the between-stance rest period. After each anchoring condition, participants will rate perceived stability. The first 18 participants will complete additional repeat assessments for intrarater reliability analysis. The protocol plans repeated-measures analyses for stance/order comparisons and intraclass correlation coefficients for reliability.

Eligibility Criteria

Interventions