Sofia Brorsson

A SIX-WEEK HAND EXERCISE PROGRAMME IMPROVES STRENGTH AND HAND FUNCTION IN PATIENTS WITH RHEUMATOID ARTHRITIS

OBJECTIVE To evaluate the effects of hand exercise in patients with rheumatoid arthritis, and to compare the results with healthy controls. METHODS Forty women (20 patients with rheumatoid arthritis and 20 healthy controls) performed a hand exercise programme. The results were evaluated after 6 and 12 weeks with hand force measurements (with a finger extension force measurement device (EX-it) and finger flexion force measurement with Grippit). Hand function was evaluated with the Grip Ability Test (GAT) and with patient relevant questionnaires (Disability of the Arm, Shoulder, and Hand (DASH) and Short Form-36). Ultrasound measurements were performed on m. extensor digitorum communis for analysis of the muscle response to the exercise programme. RESULTS The extension and flexion force improved in both groups after 6 weeks (p < 0.01). Hand function (GAT) also improved in both groups (p < 0.01). The rheumatoid arthritis group showed improvement in the results of the DASH questionnaire (p < 0.05). The cross-sectional area of the extensor digitorum communis increased significantly in both groups measured with ultrasound. CONCLUSION A significant improvement in hand force and hand function in patients with rheumatoid arthritis was seen after 6 weeks of hand training; the improvement was even more pronounced after 12 weeks. Hand exercise is thus an effective intervention for rheumatoid arthritis patients, leading to better strength and function.

Ultrasound evaluation in combination with finger extension force measurements of the forearm musculus extensor digitorum communis in healthy subjects

BackgroundThe aim of this study was to evaluate the usefulness of an ultrasound-based method of examining extensor muscle architecture, especially the parameters important for force development. This paper presents the combination of two non-invasive methods for studying the extensor muscle architecture using ultrasound simultaneously with finger extension force measurements.MethodsM. extensor digitorum communis (EDC) was examined in 40 healthy subjects, 20 women and 20 men, aged 35–73 years. Ultrasound measurements were made in a relaxed position of the hand as well as in full contraction. Muscle cross-sectional area (CSA), pennation angle and contraction patterns were measured with ultrasound, and muscle volume and fascicle length were also estimated. Finger extension force was measured using a newly developed finger force measurement device.ResultsThe following muscle parameters were determined: CSA, circumference, thickness, pennation angles and changes in shape of the muscle CSA. The mean EDC volume in men was 28.3 cm3 and in women 16.6 cm3. The mean CSA was 2.54 cm2 for men and 1.84 cm2 for women. The mean pennation angle for men was 6.5° and for women 5.5°. The mean muscle thickness for men was 1.2 cm and for women 0.76 cm. The mean fascicle length for men was 7.3 cm and for women 5.0 cm. Significant differences were found between men and women regarding EDC volume (p < 0.001), CSA (p < 0.001), pennation angle (p < 0.05), muscle thickness (p < 0.001), fascicle length (p < 0.001) and finger force (p < 0.001). Changes in the shape of muscle architecture during contraction were more pronounced in men than women (p < 0.01). The mean finger extension force for men was 96.7 N and for women 39.6 N. Muscle parameters related to the extension force differed between men and women. For men the muscle volume and muscle CSA were related to extension force, while for women muscle thickness was related to the extension force.ConclusionUltrasound is a useful tool for studying muscle architectures in EDC. Muscle parameters of importance for force development were identified. Knowledge concerning the correlation between muscle dynamics and force is of importance for the development of new hand training programmes and rehabilitation after surgery.

RELATIONSHIP BETwEEN FINGER FLEXION AND EXTENSION FORCE IN HEALTHy wOMEN AND wOMEN wITH RHEUMATOID ARTHRITIS

OBJECTIVE Balance between flexor and extensor muscle activity is essential for optimal function. The purpose of this pilot study was to compare the relationship between maximum finger flexion force and maximum finger extension force in women with rheumatoid arthritis and healthy women. METHODS Twenty healthy women (median age 61 years) and 20 women with rheumatoid arthritis (median age 59.5 years, median disease duration 16.5 years) were included in the study. Finger extension force was measured with an electronic device, EX-it, and finger flexion force using Grippit. The Grip Ability Test and the score from the patient-reported outcome Disability Arm Shoulder and Hand were used to evaluate activity limitations. RESULTS Patients with rheumatoid arthritis showed significantly decreased hand function compared with healthy controls. A correlation was found between extension force and flexion force in the healthy group (r = 0.65, p = 0.002),but not in the rheumatoid arthritis group (r = 0.25, p = 0.289). CONCLUSION Impaired hand function appears to influence the relationship between maximum finger flexion and extension force. This study showed a difference in the relationship between maximum finger flexion and extension force in healthy controls and those with rheumatoid arthritis.

Sport performance and perceived musculoskeletal stress, pain and discomfort in kitesurfing

The purpose of this study was to obtain an overview of the specific movement patterns in kitesurfing, and the participants’ perceptions of musculoskeletal stress, pain and discomfort. Task analysis and survey studies were used to provide an overview of the sport, and to identify problematic issues associated with the performance of the tasks. Three different methods were complimentary used for data collection: observations (n=8), a web questionnaire (n=206) and interviews (n=17). Participants were contacted through kitesurfing events and online forums. Their ages ranged from 16-62 years. The results showed that participants experienced high musculoskeletal stress for short times during a session (jumps, tricks and strong winds), and lower, static musculoskeletal stress over a longer time (crossing). High stress was most frequently perceived in abdominal muscles. Knees and feet were the sites most frequently experienced as painful, followed by the shoulders and elbows. This study provides additional information on the performance of kitesurfing and perceived musculoskeletal stress, pain and discomfort. The results can be used as input data to develop training methods and equipment for safe and comfortable performance.

Combined use of iteration, quadratic interpolation and an extra kernel for high-resolution 2D particle tracking: A first evaluation

A novel 2D particle tracking method, that uses 1) iteration, 2) fast quadratic sub-pixel estimation (with only 28 multiplications per movement), and 3) a previous kernel, has been evaluated and compared with a full-search block-matching method. The comparison with high-frequency ultrasound data (40 MHz) was conducted in silico and on phantoms, which comprised lateral, diagonal, and ellipsoidal movement patterns with speeds of 0–15 mm/s. The mean tracking error was reduced by 68% in silico and 71% for the phantom measurements. When only sub-pixel estimation was used, the decrease in the tracking error was 61% in silico and 57% for the phantom measurements. As well as decreasing the tracking error, the new method only used 70% of the computational time needed by the full-search block-matching method. With a fast method having good tracking ability for high-frequency ultrasound data, we now have a tool to better investigate tissue movements and its dynamic functionality.