Acta kinesiologiae Universitatis Tartuensis. 16(Supplement)

http://www.ester.ee/record=b1227224*es

Muscle to bone relationship in the forearm at midlife

Larger and stronger muscles are positively associated with bone strength in the growing skeleton; however, less is known about the role of muscle properties on bone strength later in life. The primary objective of this study was to examine the relationship between muscle cross sectional area (MCSA), muscle force and rate of torque development (RTD) with bone strength indices (bone strength index (BSI) and strength strain index (SSI)) in the radius of healthy middle-aged adults. All bone and muscle measurements were determined in the non-dominant forearm in a sample of 40 healthy adults (23 men, 17 women: mean age 49.5, SD 2.3 yrs). Peripheral quantitative computer tomography (pQCT) was used to scan the distal and shaft sites of the radius bone in the forearm. MCSA was determined from the forearm shaft scan. Forearm muscle force was measured by hand grip dynamometry and RTD was obtained from isometric wrist flexion from an isokinetic dynamometry protocol. Hierarchical regression analyses were used to identify whether muscle properties (MCSA, grip force, and RTD) independently predicted radius bone strength indices (BSI and SSI), after adjusting for the confounders of sex, height and weight. Steps of the regression models that included sex, height, weight and a muscle property explained between 66% and 71% of variance in distal radius BSI and between 74% and 78% variance of estimated bone strength (SSI) at the shaft site (all steps

Dynamics, Electromyography and Vibroarthrography as Non-Invasive Diagnostic Tools: Investigation of the Patellofemoral Joint

The knee joint plays an essential role in the human musculoskeletal system. It has evolved to withstand extreme loading conditions, while providing almost frictionless joint movement. However, its performance may be disrupted by disease, anatomical deformities, soft tissue imbalance or injury. Knee disorders are often puzzling, and accurate diagnosis may be challenging. Current evaluation approach is usually limited to a detailed interview with the patient, careful physical examination and radiographic imaging. The X-ray screening may reveal bone degeneration, but does not carry sufficient information of the soft tissue conditions. More advanced imaging tools such as MRI or CT are available, but expensive, time consuming and can be used only under static conditions. Moreover, due to limited resolution the radiographic techniques cannot reveal early stage arthritis. The arthroscopy is often the only reliable option, however due to its semi-invasive nature, it cannot be considered as a practical diagnostic tool. Therefore, the motivation for this work was to combine three scientific methods to provide a comprehensive, non-invasive evaluation tool bringing insight into the in vivo, dynamic conditions of the knee joint and articular cartilage degeneration. Electromyography and inverse dynamics were employed to independently determine the forces present in several muscles spanning the knee joint. Though both methods have certain limitations, the current work demonstrates how the use of these two methods concurrently enhances the biomechanical analysis of the knee joint conditions, especially the performance of the extensor mechanism. The kinetic analysis was performed for 12 TKA, 4 healthy individuals in advanced age and 4 young subjects. Several differences in the knee biomechanics were found between the three groups, identifying age-related and post-operative decrease in the extensor mechanism efficiency, explaining the increased effort of performing everyday activities experienced by the elderly and TKA subjects. The concept of using accelerometers to assess the cartilage degeneration has been proven based on a group of 23 subjects with non-symptomatic knees and 52 patients suffering from knee arthritis. Very high success (96.2%) of pattern classification obtained in this work clearly demonstrates that vibroarthrography is a promising, non-invasive and low-cost technique offering screening capabilities