Development and Validation of a Movement and Activity in Physical Space Score as a Functional Outcome Measure

Herrmann SD, Snook EM, Kang M, Scott CB, Mack MG, Dompier TP, Ragan BG. Development and validation of a Movement and Activity in Physical Space score as a functional outcome measure. Arch Phys Med Rehabil 2011;92:1652-8. Objective: To develop and validate a functional measure, the Movement and Activity in Physical Space (MAPS) score, that encompasses both physical activity and environmental interaction. Design: Observational matched-pair cohort with 2-month follow-up. Setting: General community under free-living conditions. Participants: Adult participants (N=18; n=9 postsurgical, n=9 matched control; mean age +/- SD, 28.9 +/- 12.0y) were monitored by an accelerometer and global positioning system receiver for 3 days within 1 week (4.1 +/- 2.8d) after knee surgery (T=0) and 2 months later (T+2). The healthy controls were matched for age, sex, smoking, perceived physical activity level, and occupation of a postsurgical participant. Correlation, t test (with Bonferroni adjustment: alpha=.05/2), analysis of variance, and intraclass correlation coefficient were used to establish validity and reliability evidence. Interventions: Not applicable. Main Outcome Measure: MAPS scores. Results: MAPS scores were moderately correlated with the Knee Injury and Osteoarthritis Outcome Score (P<.05). There was a significant group difference at T = 0 for MAPS (t(9.9)=-3.60; P=.01). Analysis of variance results for the MAPS indicated a time and group interaction (F-1,F-12=4.60, P=.05). Reliability of 3 days of MAPS scores ranged from 0.75 to 0.81 (postsurgical and control), and 2-month test-retest reliability in the control group was 0.94. Conclusions: The results provide a foundation of convergent and known-group difference validity evidence along with reliability evidence for the use of MAPS as a functional outcome measure.