RATIONALE: HPOT is an occupational, physical, or speech therapy treatment strategy that utilizes equine movement to improve physical, cognitive, and socioemotional functioning. HPOT has been growing in popularity in the United States, producing many claims of benefits not yet extensively investigated.

DESIGN: A systematic mapping review was conducted. Systematic mapping reviews produce a map of a broad topic, such as HPOT, to organize, categorize, and describe current knowledge. By identifying gaps and strengths in knowledge, such reviews can generate future hypotheses, theories, and practice guidelines.

PARTICIPANTS: A search of nine databases produced 1,526 peer-reviewed articles. Inclusion and exclusion coding produced 76 articles directly relevant to HPOT, which comprised the final database.

METHOD: The 76 included articles, including PDF copies of each, were imported into the software program, EndNote, for bibliographic organization and management.

ANALYSIS: A data extraction tool (DET) was developed to extract information relevant to each research question from included articles. Kappa coefficients of .74 or better indicated excellent interrater reliability in using the DET. The DET was imported into Microsoft Access, wherein all articles were coded. To address Aim 1, descriptive statistics and visual data displays relevant to each research question were completed. These findings plus key impressions of articles were used to address Aim 2.

RESULTS: Children (≤12 yr) were the most popular age served, producing 40 articles (53%); 27 articles (36%) addressed cerebral palsy exclusively, and the remaining 49 articles (64%) addressed a variety of conditions including autism, stroke, and multiple sclerosis among others. Forty articles (53%) did not specify involved disciplines, and only 3 articles (4%) specified occupational therapy.

The few theoretical explanations of why HPOT worked addressed the horse’s movement, motor learning, and sensory integration. Occupation as a mechanism of change was never addressed. Although some articles richly described interventions, most did not. Outcomes emphasized improvements in gross motor function. Most research was quantitative and used descriptive and single-subject design approaches.

DISCUSSION: The map of HPOT knowledge produced by this 35-yr systematic mapping review shows four prominent landmarks: children with cerebral palsy, gross motor outcomes, motor and sensory theories, and descriptive quantitative research approaches. Scattered or barely emerging areas of knowledge evident on the horizon pertain to other populations and ages, practitioners’ disciplinary backgrounds, intervention details and processes, and activity and participation level outcomes. Although cerebral palsy findings and more diverse emerging emphases in HPOT are promising, its state of clinical, theoretical, and empirical knowledge is in early development.

IMPACT STATEMENT: Greater attention to person–environment transactions in HPOT, its integration in skilled therapy services, and its relationship to occupation-centered theories, interventions, and outcomes is warranted by occupational therapy practitioners and researchers who wish to promote HPOT.