Contractile Properties Changes of the Erector Spinae Muscle During a Labour Week

Abstract

Purpose: To describe the contractile properties evolution of the erector spinae muscle during a labour week in workers who stay more than 50% of the working schedule in sedestation position. Material and method: An observational prospective study was carried out. A sample of 44 healthy subjects (age 37.1 ± 7.7 years, height 173 ± 9.1 cm, weight 72.36 ± 15.1 kg) were daily measured during 5 days. Tensiomyography (TMG) was used to measure the contractile properties of the erector spinae muscle. Result: Statistically significant increment were found in the contraction time (Tc) for Monday, Tuesday and Wednesday respect to Thursday and Friday (p<0.05). The rest of parameters (maximum radial displacement Dm), delay time (Td), sustained time (Ts) and half-relaxation time (Tr) did not show statistically significant differences. The effect size between Monday and Friday measurements was moderate (d>0.5). Conclusion: The muscle time contraction response is slowed down with the progress of a labour week. Nevertheless, the stiffness and relaxation process were not modified.