Limb immobilization is a commonly used therapeutic intervention during periods of recovery from injury. To improve rehabilitation outcomes, interventions that curtail the severe decrements in muscular size and strength that occur during immobilization are critically needed. The purpose of this study was to assess the effects of two distinct interventions during one week of knee-joint immobilization on muscular size, strength, and neuromuscular function. Thirty-nine healthy, college-aged adults (21 males and 18 females) participated in this study. Participants were randomized into one of four groups: immobilization only (n = 9) , immobilization + action observation/mental imagery (AOMI) (n = 10), immobilization + neuromuscular electrical stimulation (NMES) (n = 12), or a control group (n =8). The AOMI group performed daily video observation and mental imagery training of leg extensions. The NMES group performed twice daily sessions of vastus lateralis (VL) and rectus femoris (RF) stimulation at increasing intensities. Muscular size, muscular strength, and neuromuscular function were measured before and after the immobilization period. The results of multiple analyses of covariance (ANCOVAs) indicated that neither AOMI nor NMES significantly mitigated disuse-induced deficits. However, based on percent differences in outcomes between groups, AOMI may hold promise as an effective method of maintaining greater levels of strength during periods of immobilization, as ANCOVA adjusted posttest means indicated 10.7% greater MVC peak torque for the AOMI group versus the immobilization group, as well as 18.2% and 9.6% greater concentric isokinetic peak torque at 30°/s and 180°/s, respectively. Additionally, when examining within group changes, AOMI resulted in increased concentric isokinetic peak torque at 30°/s by 7.2%. Given the daily video/imagery content of the AOMI group, successful AOMI interventions are likely highly specific, and may be modulated by increased corticospinal excitability. These findings may have clinically significant implications for those undergoing periods of prescribed immobilization.


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Graduation Date





Stock, Matt


Doctor of Philosophy (Ph.D.)


College of Community Innovation and Education


Learning Sciences and Educational Research

Degree Program

Education; Exercise Physiology


CFE0009184; DP0026780





Release Date

August 2022

Length of Campus-only Access


Access Status

Doctoral Dissertation (Open Access)