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-term survivors of childhood malignancies relative to age and sex-matched controls, and to relate the muscle strength observations to the therapeutic agents used and possible hormonal disturbances.


METHODS
Age and sex-matched cohort study.


METHODS
Referral center in the northern part of Finland.


METHODS
Forty-six long-term survivors of childhood cancer. Mean age at examination 19.1 years and median off-therapy time 9.4 years.


METHODS
Isokinetic dynamometer testing.


METHODS
Measurements of trunk muscle peak torque (PT) and total work done (TWD) were performed at angle speeds of 50 degrees/sec and 200 degrees/sec. The results were normalized relative to body fat-free weight (FFW).


RESULTS
PT in the trunk muscles was lower in the patients at both angle speeds (mean normalized PT = 5.7Nm/kgFFW vs 7.6Nm/kgFFW for controls at 50 degrees/sec), as also was TWD except for extension TWD at the higher angle speed (mean normalized TWD = 59.9J/kgFFW vs 84.6J/kgFFW for controls at 200 degrees/sec). The normalized PT at 50 degrees/sec and TWD at 200 degrees/sec were lower in the males with testicular damage; also, low age at diagnosis correlated positively with muscle strength and performance. There were no differences in normalized 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 secretion still had lower normalized PTs and TWDs than the controls.


CONCLUSIONS
Survivors of childhood malignancies have decreased maximal trunk muscle strength and performance. The etiology of this effect remains unclear, but young age at diagnosis, as well as serum testosterone levels in male survivors, evidently influence muscle strength and performance.
D000293:Adolescent; D000328:Adult; D000886:Anthropometry; D016022:Case-Control Studies; D002648:Child; D015331:Cohort Studies; D005260:Female; D005387:Finland; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D018908:Muscle Weakness / Q000175:diagnosis / Q000209:etiology*; D009369:Neoplasms / Q000150:complications* / Q000628:therapy; D011897:Random Allocation; D012737:Sex Factors; D017741:Survivors; D013739:Testosterone / Q000097:blood; D013997:Time Factors
D013739:Testosterone