Assessment of isokinetic muscle strength in women who are obese.
METHODS
Cross-sectional study of isokinetic trunk and knee muscle strength in women who are obese.


OBJECTIVE
To provide reference values, to identify variables that affect peripheral muscle strength, and to provide recommendations for isokinetic testing of trunk and knee muscles in women who are obese and morbidly obese.


BACKGROUND
The assessment of peripheral muscle strength is useful for the quantification of possible loss of strength, for exercise prescription, and for the evaluation of the effect of training programs in obese individuals.


METHODS
Isokinetic trunk and leg muscle strength was assessed in 241 women who were obese (18-65 years, body mass index (BMI) > or = 30 kg/m2). Trunk flexion and extension peak torque (PT) was measured using the Cybex TEF dynamometer; trunk rotation (TR) PT was measured using the Cybex TORSO dynamometer; and knee flexion/extension (KFE) PT was measured using the Cybex 350 dynamometer. Body composition was assessed using the bioelectrical impedance method; physical activity was assessed using the Baecke questionnaire; and peak VO2 was assessed using an incremental exercise capacity test on a bicycle ergometer. To identify variables related to muscle strength, Pearson correlations were computed and a stepwise multiple regression analysis was performed.


RESULTS
Pearson correlation coefficients of all strength measurements at 60 degrees/s revealed low-to-moderate negative associations with age and positive associations with mass, height, fat free mass (FFM), and peak VO2 (P < 0.05), except for gravity-uncorrected trunk extension strength, which was not related to mass. The sports index of the Baecke questionnaire was associated with TR PT (r = 0.20, P < 0.01) and KFE PT (r = 0.18, P < 0.05).


CONCLUSIONS
The weight of the trunk accounts largely for the measured trunk extensor and flexor strength in women who are obese. Contributing variables of isokinetic trunk flexion and extension strength in women who are obese are age, height, and FFM; whereas sports activities and aerobic fitness are contributing factors for trunk rotational and knee extension strength. Recommendations for measuring isokinetic muscle strength in individuals who are obese are provided.
Hulens
Maria
M
Department of Rehabilitation Sciences, Faculty of Physical Education and Physiotherapy, Katholieke Universiteit, Leuven, Belgium. maria.hulens@flok.kuleuven.ac.be
Vansant
Greet
G
Lysens
Roeland
R
Claessens
Albrecht L
AL
Muls
Erik
E
D000328:Adult; D000368:Aged; D001823:Body Composition; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D006801:Humans; D007717:Knee / Q000502:physiology; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D009765:Obesity / Q000503:physiopathology*; D010101:Oxygen Consumption; D012016:Reference Values; D012044:Regression Analysis; D012307:Risk Factors; D012399:Rotation; D011795:Surveys and Questionnaires; D013909:Thorax / Q000502:physiology; D019415:Torque