DECREASED ISOKINETIC TRUNK MUSCLE STRENGTH AND PERFORMANCE IN LONG-TERM SURVIVORS OF CHILDHOOD MALIGNANCIES - CORRELATION WITH HORMONAL DEFECTS

Objective: To evaluate trunk muscle strength and performance in long-t erm survivors of childhood malignancies relative to age and sex-matche d controls, and to relate the muscle strength observations to the ther apeutic agents used and possible hormonal disturbances. Design: Age an d sex-matched cohort study. Setting: Referral center in the northern p art of Finland. Patients: Forty-six long-term survivors of childhood c ancer. Mean age at examination 19.1 years and median off-therapy time 9.4 years. Intervention: Isokinetic dynamometer testing. Main Outcome Measures: Measurements of trunk muscle peak torque (PT) and total work done (TWD) were performed at angle speeds of 50 degrees/sec and 200 d egrees/sec. The results were normalized relative to body fat-free weig ht (FFW). Results: PT in the trunk muscles was lower in the patients a t both angle speeds (mean normalized PT = 5.7Nm/kg(FFW) vs 7.6Nm/kg(FF W) for controls at 50 degrees/sec), as also was TWD except for extensi on TWD at the higher angle speed (mean normalized TWD = 59.9J/kg(FFW) vs 84.6/kg(FFW) for controls at 200 degrees/sec). The normalized PT at 50 degrees/sec and TWD at 200 degrees/sec were lower in the males wit h testicular damage; also, low age at diagnosis correlated positively with muscle strength and performance. There were no differences in nor malized PTs or TWDs between cranial radiation and non-radiation cases, or between growth-hormone-deficient and non-deficient cases, and the patients without cranial radiation or with normal growth hormone secre tion still had lower normalized PTs and TWDs than the controls. Conclu sions: Survivors of childhood malignancies have decreased maximal trun k muscle strength and performance. The etiology of this effect remains unclear, but young age at diagnosis, as well as serum testosterone le vels in male survivors, evidently influence muscle strength and perfor mance. (C) 1995 by the American Congress of Rehabilitation Medicine an d the American Academy of Physical Medicine and Rehabilitation.