The influence of lower limbs muscle strength and power on the functional performance of women with back pain syndromes

Introduction
The purpose of the study was to assess the occurrence of deficits in strength and power of lower limb muscles and functional performance of patients with back pain syndromes and to identify the factors that affect them.

Material and methods
The clinical material consisted of 43 patients (28 women with back pain syndrome, the control group - 15 people). Up & go test, Barthel Index, five - time standing up test, Tinetti test, assessment of power (Pmax), strength and optimal shortening velocity (Vopt), Geriatric Depression Scale (GDS), pain assessment were performed in all patients.

Results
The patients from the control group achieved better results in the five - time standing - up test (p = 0,006), in the Tinetti test (p = 0,04) and had higher knee extensors muscle strength (p = 0,005). Functional performance in patients with lumbosacral spine pain syndromes was determined by the strength of the knee extensors muscles (Up & go test Rho = 0,54; p = 0,005; five - time standing up test Rho = 0,39; p = 0,04; Tinetti for gait Rho = 0,4; p = 0,04). Age and height influenced the parameters of muscle function.

Conclusions
Patients with back pain syndromes are characterized by reduced functional performance and have knee extensors muscle deficit in relation to people without back pain. Knee extensors muscle strength has the greatest impact on functional performance in patients with back pain. Younger and taller people have better results in muscle function tests.