Diabetes Care, Vol 21, Issue 4 604-609, Copyright © 1998 by American Diabetes Association
Muscular endurance in long-term IDDM patients
H Andersen
Department of Neurology, Aarhus University Hospital, Denmark. henning@akhphd.au.dk
OBJECTIVE: To determine the short-term muscular endurance and working
capacity of leg muscles in long-term IDDM patients in relation to
neuropathic complications, muscle strength, and metabolic control. RESEARCH
DESIGN AND METHODS: The muscular endurance of extensors and flexors at the
ankle and knee was assessed in 44 IDDM patients and in 44 matched control
subjects during 30 maximal isokinetic movements. The endurance index was
the work performance of the last 5 movements relative to the first 5
movements. Total work was the summated work of all movements. All patients
underwent a neurological evaluation, nerve conduction studies, and
quantitative sensory tests. RESULTS: The combined endurance index of the
ankle extensors and flexors was 70% (51-88) (median [range]) in the
diabetic group and 65% (55-82) in the control group (P < 0.01). For knee
extensors and flexors the combined endurance index was 65% (55-103) for the
diabetic patients and 63% (48-75) in the control subjects (P < 0.01).
The endurance index related neither to the severity of neuropathy nor to
the metabolic control (blood glucose and HbA1c) for any of the muscle
groups. Diabetic patients had reduced strength of all muscle groups
(14-24%, P < 0.02) and impaired total work performance (15-20%, P <
0.01) for ankle movements. CONCLUSIONS: Long-term IDDM patients have
increased endurance but reduced strength and work performance of leg
muscles. The combined effect of the motor abnormalities is suggested to
give rise to functional impairment, including an increased risk of falls
and injuries.