Body posture and trunk muscle activity in women following treatment of breast cancer.

BACKGROUND Treatment of breast cancer can lead to abnormally shaped anteroposterior spinal curvatures, which consequently leads to functional disturbances of trunk muscles. The aim of the paper was to investigate the correlation between trunk muscle function and type of body posture in women receiving treatment for breast cancer. MATERIAL AND METHODS Fifty women following treatment of breast cancer were included in the study. The average age of the women was 61 years (± 8.67), average body height was 157.5 cm (± 5.49) and average body weight was 74 kg (± 13.10). 84% of the women underwent a modified radical mastectomy, while 16% underwent a breast-sparing procedure. The average time since surgery was 6.4 years (± 5.15). Additionally 90% of women were subjected to adjuvant treatment. The force and velocity parameters of the flexor and extensor muscles of trunk were assessed in all participants at angular velocities of 60 degrees/s and 120 degrees/s in an isokinetic examination unit. A photogrammetric evaluation of the anteroposterior curvatures of the spine was also carried out. On the basis of the value of a compensation index (μ), the participants were divided into three body posture subgroups: kyphotic (K), lordotic (L) and balanced (R. RESULTS 40% of the women (20 patients) demonstrated a balanced body posture with equal thoracic and lumbar curvatures, 30% (15 patients) demonstrated a kyphotic body posture with a dominance of the kyphotic curvature over the lordotic one, and another 30% (15 patients) demonstrated a dominance of the lordotic over kyphotic curvature. Women with a lordotic body posture had the highest correlation between the activity of trunk muscles at loads of 60 degrees/s and 120 degrees/s and body posture in the sagittal plane. Minimal correlation, in turn, was observed in the women with a balanced body posture. CONCLUSIONS 1. The most marked involvement of trunk muscles was observed in women with a lordotic body posture. 2. Women with a balanced posture did not show any correlation between muscle activity and the parameters characterizing this posture.