Open Access Research article

Assessment of functional impairment after knee anterior cruciate ligament reconstruction using cardiorespiratory parameters: a cross-sectional study

Marília Santos Andrade1*, Claudio Andre Barbosa de Lira2, Rodrigo Luiz Vancini3, Fernanda Patti Nakamoto1, Moisés Cohen4 and Antonio Carlos da Silva1

Author Affiliations

1 Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, Brazil

2 Setor de Fisiologia Humana e do Exercício, Faculdade de Educação Física, Universidade Federal de Goiás, Goiânia, Brazil

3 Centro de Educação Física e Desporto, Universidade Federal do Espírito Santos, Vitória, Brazil

4 Departamento de Ortopedia e Traumatologia, Universidade Federal de São Paulo, São Paulo, Brazil

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BMC Musculoskeletal Disorders 2014, 15:163  doi:10.1186/1471-2474-15-163

Published: 20 May 2014



A dynamic sub-maximum exercise with the same absolute intensity, performed with different muscle groups, may present exacerbated cardiorespiratory responses. Therefore, cardiorespiratory responses to unilateral exercise may identify bilateral differences. The purpose of this study was to verify whether the cardiorespiratory responses to lower limb exercise display counter-lateral differences, and if they could be used to assist athletes and health professionals involved in rehabilitation.


Nine individuals participated in this cross-sectional study. They had been treated in a private rehabilitation clinic and submitted to intra-articular reconstruction of the anterior cruciate ligament. The cycling exercise with the same sub-maximal intensity and with one lower limb was used to gather data. Cardiorespiratory responses to exercise were compared between exercises performed with the involved and uninvolved limb after five minutes of exercise.


Cardiorespiratory responses to exercise performed with the involved limb presented higher values after five minutes of cycling: oxygen uptake (+7%), carbon dioxide production (+10%), minute ventilation (+20%), breathing frequency (+19%), ventilatory equivalent for oxygen (+14%), end-tidal pressure of O2 oxygen (+4%), end-tidal pressure of O2 carbon dioxide (-9%) and heart rate (+9%).


The exacerbated responses, including increase of the ventilatory equivalent and decrease of end-tidal pressure of carbon dioxide, indicate that this exercise protocol may be useful in the characterization of the functional deficit of the surgical limb during rehabilitation.

Knee injury rehabilitation; Physiological responses; Heart rate; Oxygen uptake