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Effects of excess body mass on strength and fatigability of quadriceps in postmenopausal women

Paolillo, Fernanda Rossi PhD1,2; Milan, Juliana Cristina PT3; Bueno, Patrícia de Godoy MSc4; Paolillo, Alessandra Rossi MSc5; Borghi-Silva, Audrey PhD3; Parizotto, Nivaldo Antonio PhD6; Arena, Ross PhD7; Kurachi, Cristina PhD1,2; Bagnato, Vanderlei Salvador PhD1,2

Menopause:
doi: 10.1097/gme.0b013e3182364e80
Original Articles
Abstract

Objective: Obesity is a major public health problem leading to, among other things, reduced functional capacity. Moreover, obesity-related declines in functional capacity may be compounded by the detrimental consequences of menopause. The aim of this study was to understand the potential effects of excess body mass on measures of functional capacity in postmenopausal women.

Methods: Forty-five postmenopausal women aged 50 to 60 years were divided into two groups according to body mass index (BMI): obese (BMI, ≥30 kg/m2; n = 19) and nonobese (BMI, 18.5-29.9 kg/m2; n = 26). To determine clinical characteristics, body composition, bone mineral density, and maximal exercise testing was performed, and a 3-day dietary record was estimated. To assess quadriceps function, isokinetic exercise testing at 60° per second (quadriceps strength) and at 300° per second (quadriceps fatigue) was performed.

Results: The absolute value of the peak torque was not significantly different between the groups; however, when the data were normalized by body mass and lean mass, significantly lower values were observed for obese women compared with those in the nonobese group (128% ± 25% vs 155% ± 24% and 224% ± 38% vs 257% ± 47%, P < 0.05). The fatigue index did not show any significant difference for either group; however, when the data were normalized by the body mass and lean mass, significantly lower values were observed for obese women (69% ± 16% vs 93% ± 18% and 120% ± 25% vs. 135% ± 23%, P < 0.01).

Conclusions: Our results show that despite reduced muscle force, the combination of obesity and postmenopause may be associated with greater resistance to muscle fatigue.

In Brief

This study showed that despite reduced muscle force, the combination of obesity and postmenopause can be associated with greater resistance to muscle fatigue.

Author Information

From the 1Optics Group from Instituto de Física de São Carlos, University of São Paulo, São Paulo, Brazil; 2Biotechnology Program, Federal University of São Carlos, São Carlos, Brazil; 3Cardiopulmonary Physiotherapy Laboratory, Department of Physical Therapy, Federal University of São Carlos, São Carlos, Brazil; 4Department of Physiology, Federal University of São Carlos, São Carlos, Brazil; 5Bioengineer Program, University of São Paulo, São Paulo, Brazil; 6Electrothermophototherapy Laboratory, Department of Physical Therapy and Biotechnology Program, Federal University of São Carlos, São Carlos, Brazil; and 7Physical Therapy Program, Department of Orthopaedics and Rehabilitation, University of New Mexico, Albuquerque, NM.

Received June 20, 2011; revised and accepted September 6, 2011.

Funding/support: This study was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo Grants 98/14270-8 and05/59427-7, Conselho Nacional de Desenvolvimento Científico e Tecnológico, and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.

Financial disclosure/conflicts of interest: None reported.

Address correspondence to: Fernanda Rossi Paolillo, PhD, University of São Paulo (USP), Av. Trabalhador Sãocarlense, 400 Y Centro, CEP 13560-970, São Carlos, SP, Brazil. E-mail: fer.nanda.rp@hotmail.com

©2012The North American Menopause Society