Lumbar stabilization exercises (LSE) lead to high levels of erector spinae muscle (ESM) activation, which has a positive effect on improving physical function. The purpose of this study is to identify factors explaining changes in muscle strength after 7 weeks of LSE and to evaluate changes in stiffness and contraction of the ESM. All participants (male: n = 42, age = 28.26 ± 10.97) were assessed for 60°/s isokinetic extensor muscle strength and tension using a tensiomyography (TMG) and isokinetic device before and after LSE. Maximum displacement (Dm) and average velocity up to 90% Dm (Vc 90) were significantly different before and after LSE. Additionally, participants’ 60°/s isokinetic extensor strength was significantly higher after exercise. A regression analysis was conducted to test the explanatory power of the variables, and positive results were obtained in the increase in extensor strength before and after Vc 90 and LSE. Furthermore, statistical significance was set at p < 0.05. After LSE, the increase in 60°/s isokinetic extensor strength and ESM’s Dm and Vc 90 can be interpreted as positive changes post-exercise in endurance muscles with a higher percentage of type I fibers. Our results can contribute to predicting the long-term exercise effect in sedentary workers and developing an individualized strategic exercise program.

Purpose: The purpose of this study was to examine the effects of a combined core stabilization exercise program on the static contractile properties of the erector spinae and the isokinetic muscle function of trunk flexion and extension in office workers aged twenty years and older. Methods: All participants performed a combined core stabilization exercise program, for seven weeks. And all participants were assessed using tensiomyography to evaluate the contractile properties of the erector spinae, and also assessed for isokinetic trunk strength. Results: As a result of tensiomyography, we found that significant main effect of sex on contraction time (p ≤ 0.001), and maximum radial displacement, velocity of contraction demonstrated significant main effects for sex and time (p ≤ 0.001). Regarding isokinetic trunk muscle function, significant main effects of sex and time were observed for trunk flexion, extension, and the flexion/extension ratio at 60 °/sec (p ≤ 0.001) and 90 °/sec (p ≤ 0.001). In addition, trunk extension at 90 °/sec demonstrated a significant sex-by-time interaction (p = 0.010). Conclusions: These findings suggest that overall, the 7-week combined core stabilization exercise program was effective in enhancing the static contractile properties of the erector spinae and improving trunk isokinetic muscle function.