Neuromuscular efficiency of the quadriceps in women with and without patellofemoral pain

Abstract

ABSTRACT Patellofemoral pain (PFP) may contribute to less activation of the quadriceps muscle, favoring joint overload and pain. Neuromuscular efficiency (NME) is a variable that evaluates the relationship between the amount of neural stimuli and the ability to generate force of in a given muscle, with the most efficient being the one that produces greater muscle force, with less activation of muscle fibers. In this sense, this study aimed to evaluate the strength and NME of knee extensors in women with and without patellofemoral pain. A total of 24 adult women, recruited via a questionnaire, aged from 18 to 30 years, with and without patellofemoral pain, participated in this study. Anamnesis, anterior knee pain scale, and numerical visual scale were applied. Subsequently, the knee extensor strength, with a hand-held dynamometer, and the NME of vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) were assessed. For statistical analysis, appropriate tests were adopted to compare variables between groups and correlate them. In all statistical tests, a α<0.05 was adopted. Results showed that women with PFP had 61% lower NME in the VM and 52% in the VL, compared to the group without pain. No significant difference was found for knee extensor strength between groups. We conclude that pain negatively influences VM and VL recruitment but does not change quadriceps ability to generate strength.