Evaluation of bilateral deficit in isometric contractions of the knee extensors

Ronei Silveira Pinto, Cíntia Ehlers Botton, Bruno Tomasi Kuckartz, Cláudia Silveira Lima, Antonio Carlos Moraes, Martim Bottaro


Strength training has been reported as an important tool for enhancing and maintaining health. Resistance exercises can be executed unilaterally or bilaterally. Some studies have reported lower strength and electromyography (EMG) signal values in bilateral conditions than the sum of these values in unilateral conditions. This difference in strength and EMG is called the bilateral deficit. The aim of this study was to evaluate the strength and EMG activity of the rectus femoris and vastus lateralis during unilateral and bilateral isometric knee extension. The sample consisted of 10 non-resistance trained males aged 18 to 30 years. Strength and EMG were recorded through use of a load cell and surface electrodes, respectively. A 120° knee extension was used for the isometric knee extension test. The results showed significantly higher values for strength and EMG signal (p <0.05) in unilateral conditions, as well as bilateral deficit in both strength and EMG signal. These results suggest that unilateral training promotes greater muscle stimulation, and can thus represent an important strategy to be used in the prescription of strength training exercises.


Bilateral deficit; Electromyography; Muscle strength.

DOI: https://doi.org/10.1590/1980-0037.2012v14n2p202

The abbreviated title of the journal is Rev. Bras. Cineantropom. Desempenho Hum, which should be used in bibliographies, footnotes and bibliographical references. E-ISSN 1980-0037, impressa ISSN 1415-8426, Florianópolis, Santa Catarina, Brazil. This work is licensed under a Creative Commons Attribution 4.0 International License.