Rodrigo Ribeiro de Oliveira

Experimental Diabetes Induces Structural, Inflammatory and Vascular Changes of Achilles Tendons

This study aims to demonstrate how the state of chronic hyperglycemia from experimental Diabetes Mellitus can influence the homeostatic imbalance of tendons and, consequently, lead to the characteristics of tendinopathy. Twenty animals were randomly divided into two experimental groups: control group, consisting of healthy rats and diabetic group constituted by rats induced to Diabetes Mellitus I. After twenty-four days of the induction of Diabetes type I, the Achilles tendon were removed for morphological evaluation, cellularity, number and cross-sectional area of blood vessel, immunohistochemistry for Collagen type I, VEGF and NF-κB nuclear localization sequence (NLS) and nitrate and nitrite level. The Achilles tendon thickness (µm/100g) of diabetic animals was significantly increased and, similarly, an increase was observed in the density of fibrocytes and mast cells in the tendons of the diabetic group. The average number of blood vessels per field, in peritendinous tissue, was statistically higher in the diabetic group 3.39 (2.98) vessels/field when compared to the control group 0.89 (1.68) vessels/field p = 0.001 and in the intratendinous region, it was observed that blood vessels were extremely rare in the control group 0.035 (0.18) vessels/field and were often present in the tendons of the diabetic group 0.89 (0.99) vessels/field. The immunohistochemistry analysis identified higher density of type 1 collagen and increased expression of VEGF as well as increased immunostaining for NFκB p50 NLS in the nucleus in Achilles tendon of the diabetic group when compared to the control group. Higher levels of nitrite/nitrate were observed in the experimental group induced to diabetes. We conclude that experimental DM induces notable structural, inflammatory and vascular changes in the Achilles tendon which are compatible with the process of chronic tendinopathy.

Concurrent validity of the pressure biofeedback unit and surface electromyography in measuring transversus abdominis muscle activity in patients with chronic nonspecific low back pain

BACKGROUND The Pressure biofeedback unit (PBU) is an assessment tool used in clinical practice and research aimed to indirectly analyze the transversus abdominis (TrA) muscle activity. The concurrent validity of the PBU in a clinically relevant sample is still unclear. OBJECTIVE The purpose of this study was to evaluate the concurrent validity and diagnostic accuracy of the PBU in measuring TrA muscle activity in patients with chronic nonspecific low back pain. METHOD This study was performed using a validation, cross-sectional design. Fifty patients with chronic nonspecific low back pain were recruited for this study. To test the concurrent validity both PBU measures (index test) and superficial electromyographic measures (reference-standard test) were compared and collected by a physical therapist in a series of voluntary contraction maneuvers of TrA muscle. RESULTS Participants were on average 22 years old, weighed 63.7 kilos, 1.70 meters height and mean low back pain duration was 1.9 years. It was observed a weak and non-significant Phi coefficient (r=0.2, p<0.20). With regards to diagnostic accuracy tests, our results suggest a low sensitivity (60%) and specificity (60%) of the PBU. The positive predictive value was high (0.8) and negative predictive value was low (0.2). CONCLUSIONS Concurrent validity of the PBU in measuring TrA muscle activity in patients with chronic nonspecific low back pain is poor given the low correlation and diagnostic accuracy with superficial EMG.

The association of ankle dorsiflexion and dynamic knee valgus: A systematic review and meta-analysis

OBJECTIVE The objective of this systematic review was to evaluate the association between ankle dorsiflexion (ADF) and dynamic knee valgus (DKV). METHODS Electronic searches were conducted in MEDLINE, EMBASE, CINAHL and SPORTDiscus. A modified Downs and Black checklist was used for quality assessment and meta-analysis was performed to compare standardised mean differences (SMD) of ADF. RESULTS Seventeen studies met the inclusion criteria. Meta-analysis showed that reduced ADF is associated with participants presenting with DKV compared to controls (SMD -0.65, 95% CI -0.88 to -0.41). Subgroup analysis showed consistent results regarding different forms of ADF measurement; restriction in ADF measured in weight-bearing position (SMD -1.25, 95% CI -2.24 to -0.25), non-weight-bearing with knee flexed (SMD -0.56, 95% CI -0.97 to -0.16) or non-weight-bearing with knee extended (SMD -0.54, 95% CI -0.80 to -0.28) was significantly associated with DKV. CONCLUSION The meta-analysis results provide evidence that reduced ADF is correlated with DKV. The assessment of ADF in the clinical setting is important, as it may be related to harmful movement patterns of the lower limbs.

Experimental Diabetes Alters the Morphology and Nano-Structure of the Achilles Tendon

Although of several studies that associate chronic hyperglycemia with tendinopathy, the connection between morphometric changes as witnessed by magnetic resonance (MR) images, nanostructural changes, and inflammatory markers have not yet been fully established. Therefore, the present study has as a hypothesis that the Achilles tendons of rats with diabetes mellitus (DM) exhibit structural changes. The animals were randomly divided into two experimental groups: Control Group (n = 06) injected with a vehicle (sodium citrate buffer solution) and Diabetic Group (n = 06) consisting of rats submitted to intraperitoneal administration of streptozotocin. MR was performed 24 days after the induction of diabetes and images were used for morphometry using ImageJ software. Morphology of the collagen fibers within tendons was examined using Atomic Force microscopy (AFM). An increase in the dimension of the coronal plane area was observed in the diabetic group (8.583 ± 0.646 mm2/100g) when compared to the control group (4.823 ± 0.267 mm2/100g) resulting in a significant difference (p = 0.003) upon evaluating the Achilles tendons. Similarly, our analysis found an increase in the size of the transverse section area in the diabetic group (1.328 ± 0.103 mm2/100g) in comparison to the control group (0.940 ± 0.01 mm2/100g) p = 0.021. The tendons of the diabetic group showed great irregularity in fiber bundles, including modified grain direction and jagged junctions and deformities in the form of collagen fibrils bulges. Despite the morphological changes observed in the Achilles tendon of diabetic animals, IL1 and TNF-α did not change. Our results suggest that DM promotes changes to the Achilles tendon with important structural modifications as seen by MR and AFM, excluding major inflammatory changes.

Cross-Cultural Adaptation and Measurement Properties of the Brazilian Portuguese Version of the Victorian Institute of Sport Assessment-Achilles (VISA-A) Questionnaire

• BACKGROUND: Achilles tendon disorders are very common among athletes. It is important to measure symptoms and functional limitations objectively related to Achilles tendinopathy using outcome measures that have been validated in the language of the target population. • OBJECTIVES: To perform a cross‐cultural adaptation and to evaluate the measurement properties of the Brazilian version of the Victorian Institute of Sport Assessment‐Achilles (VISA‐A) questionnaire. • METHODS: This clinical measurement study adapted the VISA‐A questionnaire to Brazilian Portuguese (VISA‐A‐Br). The adapted questionnaire was then tested on 2 occasions within an interval of 5 to 14 days. This study evaluated the following measurement properties: internal consistency, test‐retest reliability, measurement error, construct validity, and ceiling and floor effects. • RESULTS: The VISA‐A‐Br showed good internal consistency (Cronbach &agr; = .79; after excluding 1 item at a time, Cronbach &agr; = .73‐.84), good testretest reliability (intraclass correlation coefficient model 2,1 = 0.84; 95% confidence interval: 0.71, 0.91), an acceptable measurement error (standard error of measurement, 3.25 points; smallest detectable change, 9.02 points), good construct validity (Spearman correlation coefficients for the Lower Extremity Functional Scale, 0.73; the Foot and Ankle Outcome Score pain subscale, 0.66; other symptoms subscale, 0.48; function in daily living subscale, 0.59; function in sport and recreation subscale, 0.67; and foot and ankle‐related quality of life subscale, 0.70), and no ceiling and floor effects. • CONCLUSION: The clinical measurement properties of the VISA‐A‐Br are equivalent to those of the original version, and the instrument has been validated and confirmed as reliable to measure pain and function among the Brazilian population with Achilles tendinopathy. This adaptation of the questionnaire may be used in clinical and scientific settings.

Index of fatigue quadriceps in soccer athletes after anterior cruciate ligament reconstruction

Objective The present study aimed to evaluate the muscle fatigue of the quadriceps muscle in high-performance soccer players undergoing (anterior cruciate ligament) ACL reconstruction. Methods We evaluated 17 high-performance soccer players from three professional soccer teams of a state in Brazil from August 2011 to July 2012. All subjects were evaluated between 5.5 and 7 months after ACL reconstruction with a Biodex® isokinetic dynamometer (System 4 Pro) with test protocol CON/CON at 60°/s and 300°/s with 5 and 15 repetitions, respectively. In the calculation of local muscle fatigue, the fatigue index was used, which is calculated by dividing the labor done in the first one-third of the repetitions by that done at the final one-third of the repetitions, and multiplying by 100 to express a unit in percentage (i.e., as a discrete quantitative variable). Results All subjects were male, with a mean age of 21.3 ± 4.4 years and mean BMI 23.4 ± 1.53 cm; left dominance was observed in 47% (n = 8) of athletes, and right dominance, in 53% (n = 9) of athletes; and the limb involved in the lesion was the dominant in 29% (n = 5) and the non-dominant in 71% (n = 12). Fatigue rates were 19.6% in the involved limb and 29.0% in the non-involved limb. Conclusion The results allow us to conclude that there was no significant difference between the limbs involved and not in ACL injuries regarding local muscle fatigue. No association was observed between the dominant side and the limb involved in the ACL injury.

Entrenamiento físico moderado causan cambios en las propiedades biomecánicas del tendón de aquiles

The effect of aerobic training has presented conflicting results regarding the bio- mechanical responses submitted by the tendon after a period of moderate aerobic training such as running. This study aims to evaluate the effect of a protocol running on a treadmill at moderate intensity on the mechanical properties of the Achilles tendons of rats. For mechanical test the tendons were pulled to the point of failure of the specimen. The moderate-intensity aerobic training in rats does not changes in the biomechanical properties of the Achilles tendon, thus, does not seem to pose a risk can be effective for not taking the Achilles tendon to mechanical stress and fatigue.

Treino moderado de corrida causa alterações nas propriedades biomecânicas do tendão do calcâneo

The effect of aerobic training has presented conflicting results regarding the bio- mechanical responses submitted by the tendon after a period of moderate aerobic training such as running. This study aims to evaluate the effect of a protocol running on a treadmill at moderate intensity on the mechanical properties of the Achilles tendons of rats. For mechanical test the tendons were pulled to the point of failure of the specimen. The moderate-intensity aerobic training in rats does not changes in the biomechanical properties of the Achilles tendon, thus, does not seem to pose a risk can be effective for not taking the Achilles tendon to mechanical stress and fatigue.

Do moderate running training changes the biomechanical properties of the achilles tendon

The effect of aerobic training has presented conflicting results regarding the bio- mechanical responses submitted by the tendon after a period of moderate aerobic training such as running. This study aims to evaluate the effect of a protocol running on a treadmill at moderate intensity on the mechanical properties of the Achilles tendons of rats. For mechanical test the tendons were pulled to the point of failure of the specimen. The moderate-intensity aerobic training in rats does not changes in the biomechanical properties of the Achilles tendon, thus, does not seem to pose a risk can be effective for not taking the Achilles tendon to mechanical stress and fatigue.