Development and validation of a movement and activity in physical space score as a functional outcome measure.

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: α=.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(1,12)=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.