Conclusions are misleading
EDITOR--We welcome the article by Harland et al on promoting physical activity in primary care but dispute the conclusion that these schemes are of questionable effectiveness. The title for the paragraph for This week in the BMJ that "exercise on prescription" is a waste of scarce resources is also misleading and not justified by evidence to date.
Our response stems from concerns about their intervention approach and our experience in two research endeavours: implementing a physical activity prescription scheme in New Zealand and a recently published randomised controlled trial resulting in long term improvement in physical activity for older people.
Firstly, we question whether the level of intervention with the control group (information and recommendations about activity) resulted in a comparison with a lesser intervention, rather than a true control group, perhaps underestimating the efficacy of exercise counselling.
Secondly, is lengthy motivational interviewing appropriate and replicable in a general practice setting? This approach is time intensive for general practitioners and practice nurses and perhaps limits effective long term follow up. In New Zealand 51% of general practitioners are prescribing physical activity through the Hillary commission's "green prescriptions" scheme. One of the barriers to exercise prescription is lack of time during the consultation.[4 5] We contend that interventions that are quick and simple to implement with regular practice based reinforcement offer more potential for sustainability and long term effectiveness.
Individualised assessment and programme design benefit outcome in health promotion trials. The judgment of the general practitioner is key in this area. The intervention design of a recent successful randomised controlled trial, set in Melbourne, Australia, raised the consciousness of the general practitioner through an effective educational programme, but it left the details of whom to target and the exact content of advice to the professional judgment of the general practitioners. In Newcastle the general practitioners seemed to be virtual bystanders to the design and delivery of the intervention. We contend that the skills of the general practitioners should play a central part in physical activity interventions.
We recognise the need for outcome based evaluations in this area of health promotion. A three year study has begun in New Zealand, which evaluates the long term effectiveness of green prescriptions in increasing physical activity and improving cardiovascular risk index and quality of life of middle aged and older people at risk from physical inactivity, by comparing the intervention with a true control group that receives no advice.
Exercise on prescription a waste of scarce resources? We await the evidence to answer this question.
Ngaire Kerse senior lecturer Department of General Practice and Primary Health Care, Auckland, New Zealand firstname.lastname@example.org
Sue Walker research and information manager Hillary Commission for Sport Fitness and Leisure, Wellington, New Zealand
 Harland J, White M, Drinkwater C, Chinn D, Farr L, Howel D. The Newcastle exercise project: a randomised controlled trial of methods to promote physical activity in primary care. BMJ 1999;319:828-32. (25 September.)
 Kerse NM, Jolley D, Arroll B, Flicker L, Young D. Improving health...