Comparative assessment of back extensor muscles’ endurance between nulliparous and parous women

Abstract

Background and objective:

Poor endurance of the back extensor muscles has been reported among more women than men. There are several reported reasons for its predilection but the influence of parity has not been investigated. The objective of this study was to investigate the influence of parity on back extensor muscles’ endurance between nulliparous and parous women.

Methods and Results:

146 women whose ages ranged between 21 to 60 years were recruited into the study using sampling of convenience. This consisted of 77 nulliparous women group (21–42 years) with a mean age of 32.7 ± 5.7 years and the parous women group (26–60 years) with a mean age of 41.2 ± 9.9 years. The participants performed the Biering-Sørenson test of Static Muscular Endurance (BSME) and their height, weight and percentage body fat were measured using standard procedures. Body Mass Index (BMI) and lean body mass (LBM) and body fat mass (BFM) were calculated. Data were summarized using the descriptive statistics of mean and standard deviation, Pearson’s Chi-square, Independent t-test, and Analysis of Variance were used as applicable. The α level was set at 0.05. The finding of this study showed that parous women were significantly older, heavier and had greater level of adiposity than their nulliparous counterparts. The result indicated a significant association between parity and endurance time (X² = 88.05; P=0.020), nulliparous women have significantly greater back extensor muscles’ endurance (t=4.902; P=0.000) when compared to parous women. The results suggested that the significant age and anthropometric difference between the nulliparous and parous women could contribute to the endurance differences. Number of parity is much related to back extensor muscle endurance (F= 22.32; P=0.000). Back extensor muscles’ endurance decreases as the number of parity increases.

Conclusion:

Our results suggest that parity is an important factor in the aetiology of low back extensor muscles endurance among women.