Effect ofencouragement onwalking test performance

ABSTRACr Walking tests, frequently usedtodocument effects oftreatment on exercise capacity, haveneverbeenstandardised. We studied theeffects ofencouragement on walking testperformance inarandomised study that controlled forthenatureoftheunderlying disease, timeofday, andorder effects. We randomised 43patients withchronic airflow limitation orchronic heart failure or bothtoreceive or notreceive encouragement astheyperformed serial twoandsix minute walks everyfortnight for10weeks. Simple encouragement improved performance (p< 0*02forthesixminute walk), andthemagnitude oftheeffect was similar tothatreported for patients instudies purporting toshowbeneficial effects oftherapeutic manoeuvres.Ageandtest repetition also affected performance. Theseresults demonstrate theneedforcareful standardisationoftheperformance ofwalking tests, andsuggest caution ininterpreting studies inwhich standardisation isnota majorfeature ofthestudy design. In1976McGavinetalintroduced the12minute walking test asameasure ofexercise capacity for patients withchronic lungdisease.' Since thattime walking tests, whicharesimple, easytoadminister, anduseanexercise moderelevant toeveryday activities havebeenwidely usedasmeasures ofoutcomeinclinical trials. Interventions whichhave beeninvestigated withwalking tests inpatients with chronic lungdisease include exercise rehabilitation programmes,2-4 ventilatory muscle training,5-7 and theeffects ofoxygen8 9andofvarious drugs, includingcarbimazole,'0 prednisone," naftidrofuryl,'2 bronchodilators,'3 andsedatives.'4 Although most