Cristiano Queiroz Guimarães

Electromyographic activity during active prone hip extension did not discriminate individuals with and without low back pain

BACKGROUND Changes in activation of the trunk and hip extensor muscles can result in excessive stress on the lumbar spinal structures, predisposing them to lesions and pain. OBJECTIVES To compare electromyographic activity of the gluteus maximus, semitendinosus and the erector spinae muscles between asymptomatic and individuals with low back pain during active prone hip extension exercises. METHODS Fifty individuals were recruited and divided into two groups: 30 asymptomatic (24.5 ± 3.47 years) and 20 with mechanical low back pain (28.75 ± 5.52 years). They performed active prone hip extension exercises, while the activation parameters (latency, duration and quantity of activation) of the investigated muscles were recorded by electromyography. The beginnings of the movements were detected by a motion capture system. Differences between the groups were investigated employing Student t-tests or Mann-Whitney-U tests, according to the data distribution. RESULTS No significant differences were found between the groups for any of the investigated muscles. Muscular activation patterns were similar for both groups, starting with the semitendinosus, followed by the erector spinae, and then, by the gluteus maximus. For both groups, significant delays in the onset of the gluteus maximus were observed. CONCLUSIONS The assessment of the electromyographic activity was not capable of discriminating individuals with and without low back pain, suggesting an overlap in the studied populations.

Gluteus maximus and semitendinosus activation during active prone hip extension exercises

Background: Gluteus maximus strengthening exercises are employed in clinical practice as options for the treatment of low back and sacroiliac disorders. However, no studies were found that investigated which were the best exercises to activate this muscle and justify its employment in physical therapy practice. Objective: To quantify the electromyographic (EMG) activity of the gluteus maximus and semitendinosus muscles during four modalities of therapeutic exercises. Methods: Thirty-one participants (16 men, 15 women) were selected. The EMG activities of the gluteus maximus and semitendinosus was recorded and quantified while the participants performed four modalities of therapeutic exercises, involving active prone hip extension in four positions: knee extension (KE), knee flexion (KF), lateral hip rotation and knee extension (LHRKE), and lateral hip rotation and knee flexion (LHR-KF). Results: Repeated-measures ANOVAs showed that the addition of KF or LHR increased gluteus maximus activity, whereas, KE decreased the activation of this muscle. In contrast, the exercises performed with KE increased semitendinosus activity. Conclusions: Exercises performed with KF or LHR, or a combination of the two, may be effective choices for gluteus maximus strengthening, however both KF and LHR decreased semitendinosus activity. The exercises performed with KE appeared to be an acceptable choice for semitendinosus activation.

Fatores associados à adesão ao uso de palmilhas biomecânicas

Factors Related to Compliance with Biomechanical Insole Use Background: The benefits of biomechanical insoles for treating lower limb impairment have been reported. However, in clinical practice, low compliance with the use of such orthoses has been observed, which detracts from the possible benefits. Objective: To investigate the factors related to compliance with biomechanical insole use. Method: Thirty-three subjects (aged 44 ± 14.7 years) for whom biomechanical insoles had been molded took part in this study. A questionnaire asking about the insoles and their use was applied through interviews. The study variables were established from these questions. Based on the results obtained, the participants were divided into four groups according to their compliance level: full compliance, partial compliance, irregular compliance and non-compliance. The Kruskal-Wallis test was utilized to assess differences between these groups regarding the variables investigated. Spearman correlation coefficients were utilized to investigate possible relationships between these variables and the compliance. Results: Among the 33 participants, 15.2% were fully compliant, while 42.4% abandoned the insoles. Comparing the four compliance groups in relation to the variables investigated, significant differences were observed regarding insole comfort (p=0.003), improvement attributed to the insoles (p=0.006), and degree of knowledge of the problem (p<0.002). Significant correlations (r s =0.58; p<0.001; and r s =0.50; p<0.01) were observed between compliance and the comfort and improvement attributed to the insoles, respectively. Conclusion: The findings from this study revealed that the comfort and degree of improvement attributed to the insoles may influence the compliance with the use of these orthoses. These factors are important for the success of the treatment.

Validity analysis of one-repetition maximum strength test for determining the hamstrings-to-quadriceps ratio

One of the approaches to evaluate injury prediction is the hamstrings-to-quadriceps peak torque conventional ratio (H:Q ratio). The gold standard for assessment of muscle strength in vivo is by isokinetic dynamometry; however, the one-repetition maximum strength test (1-RM) presents high correlation with isokinetic data. This study aimed to compare measures of H:Q ratio in young adults obtained by dynamometry and 1-RM testing. No significant differences were observed in the H:Q ratio when comparing 1-RM and dynamometry testing. However, there was a significant and strong correlation between the measurements obtained in the two tests. Despite this correlation, data from both tests are not equal as the H:Q ratio obtained from 1-RM test presents a systematic error. Nonetheless, the results can enhance the applicability of 1-RM test in clinical settings.