The Reliability of an Aerobic and an Anaerobic Exercise Tolerance Test in Patients with Juvenile Onset Dermatomyositis

TIM TAKKEN, JANJAAP van der NET, and PAUL J.M. HELDERS

ABSTRACT.

Objective. To investigate the reliability of an aerobic and an anaerobic exercise test in patients with juvenile dermatomyositis (JDM).

Methods. Sixteen patients with JDM (mean age 13.85 ± 6.4 yrs, range 6.7–27.2) participated. Anaerobic exercise capacity was measured using the Wingate Anaerobic Exercise Test (WAnT). Aerobic exercise test was performed using a graded exercise test to volitional exhaustion on an electronically braked cycle ergometer. Patients were tested and retested within 12.8 ± 5.7 days.

Results. Correlation coefficients and other reliability statistics indicated that peak power and mean power on the WAnT and peak oxygen uptake (VO_2peak) and maximal workload (W_max) on the aerobic exercise test could be reliably assessed in patients with JDM. Pearson (R) and intraclass correlation coefficients (ICC) were > 0.85, and typical error was < 20% for the peak power and mean power on the WAnT. On the aerobic exercise test the R and ICC were > 0.95, and typical error was < 6% for the VO_2peak and W_max.

Conclusion. We found acceptable reliability for the WAnT and very good reliability for the aerobic exercise test. This indicated that these exercise tests could be performed reliably in patients with JDM. (J Rheumatol 2005;32:734-9)

Key Indexing Terms:

SHORT-TERM MUSCLE POWER
EXERCISE TOLERANCE
EXERCISE TEST METHODS
CHILDREN
ADOLESCENTS
JUVENILE DERMATOMYOSITIS

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From the Department of Pediatric Physical Therapy and Exercise Physiology, University Hospital for Children and Youth, Het Wilhelmina Kinderziekenhuis, University Medical Center Utrecht, Utrecht, The Netherlands.

Supported by the Dutch Arthritis Association (NR 02-2-102).

T. Takken, MSc, PhD; J. van der Net, PT, PhD; P.J.M. Helders, PT, MSc, PhD.

Address reprint requests to Dr. T. Takken, Department of Pediatric Physical Therapy and Exercise Physiology, University Hospital for Children and Youth, Het Wilhelmina Kinderziekenhuis, University Medical Center Utrecht, Room KB.02.056, PO Box 85090, 3508 AB Utrecht, The Netherlands. E-mail: t.takken@wkz.azu.nl

Accepted for publication December 20, 2004.

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