Acute Responses of Postural Alignment, Kinematic Synergy, and Intermuscular Coherence to Postural Muscle Facilitation

Study Overview
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Brief Summary
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Clinicians frequently assess and intervene on postural alignment. However, research demonstrating the effects of exercise interventions in moving postural alignment toward an evidence-based standard is lacking. Part of the difficulty in establishing such evidence has been a lack of theory-motivated conceptions of what good posture is. In other words, the prevailing understanding of postural alignment is based on the negation of what has been observed to associate with bad outcomes. This study will build upon preliminary findings from our laboratory that define good postural alignment on theoretical grounds. The investigators will measure motion capture and muscle activation patterns during simple postural alignment tasks before and after 1) a corrective exercise intervention, or 2) a control intervention based designed to inhibit superficial muscle tension. The corrective exercise intervention is designed to counteract the natural patterns in which the human skeleton tends to collapse from a standing position under the influence of gravity. The control intervention consists of passive, partner-assisted stretching. Regardless of initial assignment, all participants will crossover (i.e. switch interventions) and repeat the study procedures after a 1-week washout period. Behavioral indicators of movement and nervous system coordination will be used to quantify alignment before and after exercise, as well as the consistency of those alignment patterns with theoretically-defined standards. The knowledge gained from this study will contribute to evidence-based definitions of healthy postural alignment and help identify effective interventions by which clinicians can promote good posture.

Official Title
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Acute Responses of Postural Alignment, Kinematic Synergy, and Intermuscular Coherence to Postural Muscle Facilitation

Conditions
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Posture, Musculoskeletal Equilibrium, Electromyography, Kinematics

Intervention / Treatment
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* Other: Exercise Then Stretch
* Other: Stretch Then Exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy adult 18 - 40 years of age Exclusion Criteria: Recent (< 6 months) history of lower extremity injury Recent (< 6 months) history of other musculoskeletal or neurological disorder affecting balance Contraindications to participation in physical activity

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Exercise Then Stretch<br>Participants in AB will perform the experimental (exercise) intervention first and the control (stretch) intervention second | Other: Exercise Then Stretch<br>* This arm (sequence) will perform an anti-gravity kinetic chain intervention and then a passive, partner-assisted stretching intervention, separated by a one-week washout period.<br>Other: Stretch Then Exercise<br>* This arm (sequence) will perform a passive, partner-assisted stretching intervention and then an anti-gravity kinetic chain intervention , separated by a one-week washout period.<br>|
| Other: Stretch Then Exercise<br>Participants in BA will perform the experimental (exercise) intervention second and the control (stretch) intervention first | Other: Exercise Then Stretch<br>* This arm (sequence) will perform an anti-gravity kinetic chain intervention and then a passive, partner-assisted stretching intervention, separated by a one-week washout period.<br>Other: Stretch Then Exercise<br>* This arm (sequence) will perform a passive, partner-assisted stretching intervention and then an anti-gravity kinetic chain intervention , separated by a one-week washout period.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Euclidean distance from the vector describing subject-specific, simulated gravitational collapse | This outcome is a cumulative descriptor of segment angle distance from the pattern in which an individual's posture would collapse. The reference point for each individual is calculated using both pre and post-intervention data for a given day. | Immediately before Intervention (Day 1) | 
| Euclidean distance from the vector describing subject-specific, simulated gravitational collapse | This outcome is a cumulative descriptor of segment angle distance from the pattern in which an individual's posture would collapse. The reference point for each individual is calculated using both pre and post-intervention data for a given day. | Immediately after Intervention (Day 1) | 
| Euclidean distance from the vector describing subject-specific, simulated gravitational collapse | This outcome is a cumulative descriptor of segment angle distance from the pattern in which an individual's posture would collapse. The reference point for each individual is calculated using both pre and post-intervention data for a given day. | Immediately before Intervention (Day 7) | 
| Euclidean distance from the vector describing subject-specific, simulated gravitational collapse | This outcome is a cumulative descriptor of segment angle distance from the pattern in which an individual's posture would collapse. The reference point for each individual is calculated using both pre and post-intervention data for a given day. | Immediately after Intervention (Day 7) | 
| Pooled intermuscular coherence | Weighted average of frequency-domain correlations between muscle pairs belonging to anterior, posterior, and trunk muscle groups. | Immediately before Intervention (Day 1) | 
| Pooled intermuscular coherence | Weighted average of frequency-domain correlations between muscle pairs belonging to anterior, posterior, and trunk muscle groups. | Immediately after Intervention (Day 1) | 
| Pooled intermuscular coherence | Weighted average of frequency-domain correlations between muscle pairs belonging to anterior, posterior, and trunk muscle groups. | Immediately before Intervention (Day 7) | 
| Pooled intermuscular coherence | Weighted average of frequency-domain correlations between muscle pairs belonging to anterior, posterior, and trunk muscle groups. | Immediately after Intervention (Day 7) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Top-down kinetic chain continuity | The purpose of this outcome is to quantify the communication of motion from the upper body to the lower body. In a test involving placing hands-on-head and pulling the elbows back as far as possible, the response in the lower body is quantified by posterior rotation of the tibial segment. | Immediately before Intervention (Day 1) | 
| Top-down kinetic chain continuity | The purpose of this outcome is to quantify the communication of motion from the upper body to the lower body. In a test involving placing hands-on-head and pulling the elbows back as far as possible, the response in the lower body is quantified by posterior rotation of the tibial segment. | Immediately after Intervention (Day 1) | 
| Top-down kinetic chain continuity | The purpose of this outcome is to quantify the communication of motion from the upper body to the lower body. In a test involving placing hands-on-head and pulling the elbows back as far as possible, the response in the lower body is quantified by posterior rotation of the tibial segment. | Immediately before Intervention (Day 7) | 
| Top-down kinetic chain continuity | The purpose of this outcome is to quantify the communication of motion from the upper body to the lower body. In a test involving placing hands-on-head and pulling the elbows back as far as possible, the response in the lower body is quantified by posterior rotation of the tibial segment. | Immediately after Intervention (Day 7) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Alignment, Posture, Motor control, Intervention