Introduction Lateral elbow pain is a common disorder and affects 1-3 % of the population each year. Beside the typical characterization with pain in restricted dorsal and radial deviation of the wrist and local tenderness of the lateral epicondyle, a neurodynamic dysfunction of the radial nerve can co-exist with the tendon dysfunction.  Purpose The aim of the study was to evaluate the effects of individualized neurodynamic treatment in combination with neurodynamic self-treatment in patient with persistent lateral elbow pain with a neurodynamic dysfunction of the radial nerve on grip strength, pain, disability, and function.  Method A single subject experimental design with A-B-A design was conducted. Seven participants with lateral elbow pain and a neurodynamic dysfunction of the radial nerve were recruited for the study. Five participants completed the study which consisted of individualized neurodynamic treatment directed to the neurodynamic dysfunction in combination with home exercises which included self-mobilization with sliders and/or tensioners in combination of the strengthening- and stretching exercises. The treatment was evaluated by pain-free and maximal grip strength, the Disabilities of the Arm, Shoulder and Hand (DASH) and Patient-rated Tennis Elbow Evaluation (PRTEE) questionnaires and range of motion of the upper limb neurodynamic test (ULNT) biased n. radialis.   Results The result of this SSED shows that neurodynamic treatment with manual mobilization and self-mobilization improves the ROM of the ULNT n. radialis in all five participants. Neurodynamic treatment also improved outcomes of DASH and PRTEE in 3 of the 5 participants.  Conclusion Neurodynamic treatment including manual mobilization and self-mobilization in combination with individual strength exercises tends to improve self-rated pain and disability, function and mechanosenstivity of the radial nerve in patients with persistent lateral elbow pain.

Abstract  Background: Body composition is an important health parameter in several disease conditions, e.g., the inflammatory back disease spondylarthritis (SpA). Body mass index (BMI) is the most common anthropometric body composition assessment but has several limitations. As a result, several studies have been carried out to improve its validity by combining different body parameters. Nickerson equation (NE) is one of the equations developed to address the limitation of BMI. However, the knowledge is lacking on the preference of the NE which includes BMI (body weight and height), hand grip strength, and sex to estimate body fat percent over BMI alone among individuals with spondylarthritis. Aim: This study aims to assess the association between BMI and the Nickerson equation (NE) -estimate body fat percentage- with body composition measured with bioelectrical impedance assessment (BIA) and in individuals with spondylarthritis. Methods: Thirty-two individuals with SpA 17 women and 15 men with a median (range) age of 47 (30-66) years were included. The weight (kg), length (cm), hand grip strength (kg), and sex were registered to estimate values of body composition by the NE. BIA was equally used to assess total body fat %, visceral fat (cm2), and skeletal muscle mass (kg). Associations between the NE, or body mass index (BMI), and BIA were analyzed by Spearman’s correlations (rs). Results: The result shows that the NE has a rs of 0.6 to BIA total body fat higher than the BMI correlation coefficient of 0.3 but NE has a lower coefficient of 0.3 to visceral fat than the BMI which is 0.6, NE also has a negative correlation coefficient of 0.6 to skeletal muscles.  Conclusion: This study suggested that the Nickerson Equation which combines BMI, hand grip strength, and sex is a better assessment of body composition in individuals with spondylarthritis and encourages clinicians to consider using the Nickerson equation in clinical setting instead of BMI where access to precise assessment tools is unavailable.

Background  Maximum voluntary bite force (BF) and hand grip strength (HS) serve as muscle strength markers from the jaw motor system and hand motor system.   Aim  To investigate i) differences in maximum BF and HS between dominant and non-dominant sides, ii) differences between repeated tests in the same session and iii) correlation between BF and HS.     Methods Fifteen resistance trained adults (n=6 women, mean age 24 (SD 1.04) years and n=9 men, mean age 27 (SD 4.06) years) were tested with electronic BF and HS devices, with three repeated tests per side. Paired sample T-test was used to detect differences in BF and HS between sides and whether there was a difference between repeated tests. Pearson test was used to determine correlation between BF and HS. P-value <0.05 was considered statistically significant.    Results HS showed differences between dominant and non-dominant sides in three tests (T1 P=<0.0001, T2 P=0.0002 and T3 P=0.0011). BF showed differences between repeated tests in the same session for T1-T2 (P=0.007), T1-T3 (P<0.0001) and T2-T3 (P=0.028) on dominant side and between T1-T2 (P=0.014), T1-T3 (P=0.010) on non-dominant side. Correlation between BF and HS showed r=0.41 for merged data (dominant + non-dominant side) (P=0.02).   Conclusions  In the context of resistance trained adults, the findings showed that BF did not alter between sides while HS did, with higher force production for the dominant hand. Repeated tests showed differences between tests for BF, but not for HS. A weak to moderate correlation could be observed when comparing BF to HS.

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Work-related repetitive strain injury (RSI), one of the work-related musculoskeletal disorders, is the most commonly reported occupational illness, yet the pathophysiological mechanisms are not yet clear. Using our unique RSI animal model, pathophysiological tissue responses can be examined simultaneously with behavioral responses that serve as indicators of sensorimotor function. Studies in humans and with this animal model have shown that prolonged performance of repetitive tasks leads to declines in grip strength and increased of serum pro-inflammatory cytokines, both valuable biomarkers of underlying tissue injuries. Identification of biomarkers would help to elucidate the time course of the inflammatory stage of these disorders and disease progression. Sickness responses/behaviors, normal responses and behaviors occurring as a consequence of infection or illness, are responsible for re-organizing perceptions and actions to enable individuals to respond appropriately to the infection, injury and other illnesses. These behaviors can include malaise, fatigue, increased irritability and social withdrawal, behaviors that can be beneficial when ill for avoiding others and enhancing wellness. However, sickness behaviors can also include depression, sleep disorders and an enhanced perception of illness. Although recent studies have shown that circulating pro-inflammatory cytokines in serum may trigger sickness behaviors, only a few studies have examined if there is an association between work-related musculoskeletal disorders and subsets of sickness behavior; no one to date has elucidated any plausible biological cause of this association. Also, the combined effects of both aging and performance of repetitive tasks needs more evaluation since several epidemiological studies have shown a relationship between advancing age and susceptibility to musculoskeletal disorders. Therefore, using female Sprague-Dawley rats, the aims of this dissertation project are to: 1) To determine if a systemic inflammatory response is maintained long-term in rats exposed to a moderate demand lever-pulling task with high repetition, low force (HRLF) requirements; if aging enhances this systemic inflammatory response and if this response correlates with functional motor declines; 2) To determine if performance of repetitive upper extremity tasks leads to the development of sickness behaviors (weight loss, decreased social interaction and increased aggression); 3) To determine if a relationship between repetitive upper extremity tasks lead to the development of dose- and age-dependent sickness behaviors, and, to determine if increased serum or brain inflammatory cytokines are plausible mechanisms for the induction of sickness behaviors in this model; and, lastly, 4) To determine if prophylactic or secondary systemic treatments with anti-inflammatory drugs (anti--tumor necrosis factor alpha or ibuprofen) reduces sickness behaviors in rats performing a high demand high repetition high force (HRHF) reaching and handle pulling task. This finding would be in further support of an underlying task-induced inflammatory mechanism contributing to these sickness behaviors. In the first study, the relationship between serum and grip strength was examined in aged and young adult rats performing a HRLF task. Serum levels of interleukin 1-alpha (IL-1α), interferon-gamma (IFNγ) and IL-6 were higher in aged rats in general, compared to young adult rats. Each increased more in aged trained-only and 12-week HRLF rats than in young adult trained-only and 12-week HRLF rats. Serum IL-6 showed the greatest increases, with the highest levels observed in aged 12-week HRLF rats. Grip strength declined with task performance in both age groups; however, this decline correlated negatively and only moderately with serum IL-6 levels in aged rats. Thus, aging enhanced a serum cytokine response in general, a response that was even greater with repetitive task performance. Grip strength was adversely affected by task performance in both age groups, but was apparently influenced by factors other than serum cytokine levels in young rats. In the second study, the relationship between sickness behaviors (weight loss, duration of social interaction and aggression towards novel juvenile rats), serum cytokines and brain cytokines were examined in aged and young adult rats that trained to one of two task levels before performing a HRLF task. Decreased duration of social interaction and increased aggression was greater in both young adult and aged rats that trained for 10 min/day for 4-5 weeks to learn a high force (TRHF) task, compared to young adult and aged rats that learned a low force (TRLF) task. TRHF and TRLF rats of both age groups then performed a HRLF task for 6 to 24 weeks, rats termed TRHF-HRLF and TRLF-HRLF, respectively. Declines in social interaction resolved by week 3 in young adult TRHF-HRLF rats, but were still evident in 6-week aged TRHF-HRLF rats (the final endpoint for TRHF-HRLF rats). Significant increases in aggression were observed only in TRHF-HRLF rats, in both age groups. Declines in social interaction were also observed in aged rats performing a TRLF-HRLF task through week 9, but not in young adult TRLF-HRLF rats, even those performing the HRLF task for 24 weeks. These behaviors correlated moderately with increased serum IL-6 observed in the aged task rats (both TRHF-HRLF and TRLF-HRLF) and young adult TRHF-HRLF rats, although serum TNFalpha and IL-1beta also increased with task performance. Increased IL-6 and IL-6 receptor was detected immunohistochemically in brains of aged TRHF-HRLF rats, specifically in ependymal and endothelial cells, as well as glial cells and neurons of the anterior cingulate cortex and paraventricular nucleus. Thus, training to high force, even for a short time period, induced increased sickness behaviors. Aging contributed to increased sickness behaviors in repetitive task rats, and to increased expression of IL6 and IL-6 receptor in several brain regions. In the third study, the relationships between sickness behaviors (duration of social interaction and aggression towards novel juvenile rats), serum cytokines and brain cytokines were examined in young adult rats performing a high repetition high force (HRHF) task with or without anti-inflammatory medications. Rats that trained to high force (TRHF) had decreased duration of social interaction and increased aggression; these behaviors were prevented by prophylactic anti-TNFalpha or ibuprofen treatment. Untreated TRHF rats that went on to perform a HRHF task showed decreased social interaction and increased aggression through week 12; these behaviors were attenuated by secondary anti-TNFalpha and ibuprofen treatments. Untreated HRHF rats had increased serum GroKC, IFN-gamma, IL-1beta, MIP2, MIP3a and TNFalpha. These increases were attenuated after two weeks of anti-TNFalpha treatment in HRHF weeks 5-6, and after 8 weeks of ibuprofen (in HRHF weeks 5-12). The sickness behaviors correlated moderately with increased serum Gro-KC, MIP2 and TNFalpha, and were concomitant with increased IL-1beta immunoexpression in ependymal and endothelial cells in brains of untreated TRHF and HRHF rats. Both treatments reduced the increased brain IL-1beta expression. Thus, sickness behaviors induced by overuse are attenuated by anti-inflammatory interventions that reduce task-induced increases in systemic and brain inflammatory cytokines. In conclusion, both aging and task performance increased serum inflammatory cytokine responses, the latter in an exposure-dependent manner, with a greater serum cytokine response with performance of high force tasks than low force tasks. While grip strength was adversely affected by task performance in both young and aged rats, it was influenced by factors other than serum cytokine levels. In contrast, decreased duration of social interaction and increased incidence of aggression were influenced by task-induced increases in serum and brain inflammatory cytokines, responses attenuated to baseline levels with systemic anti-inflammatory treatments. Sickness behaviors were also dose- and age-dependent, with higher incidence with performance of high force tasks than with low force tasks, and higher incidence in aged rats. We postulate that the higher incidence in aged rats is due to aged-induced brain "inflamm-aging", as they also had increased immunoexpression of IL6 and IL6 receptor in blood brain barrier cells and in glial and neurons of the hypothalamic pituitary axis. / Physical Therapy

Children with unilateral spastic cerebral palsy (USCP) have impairments affecting upper limb function, particularly in grasping abilities. Specifically, children with USCP may display precision grip impairments, which can lead to activity limitations. The interplay between feedforward and feedback control is essential for successful grasping, requiring somatosensory information to be integrated with the motor output. This integration occurs through the transmission of somatosensory information through the dorsal column medial lemniscus (DCML) pathway, while independent finger movement to grasp an object is controlled by the motor cortex via the corticospinal tract (CST). While previous studies demonstrated the CST relates to anticipatory control of grasping, this may not explain all the variance of grasp impairments in children with USCP. Although studies have highlighted the importance of sensory information in grasping in typically developing (TD) adults, there are no studies examining the relationship between brain structure and function in terms of precision grip impairments in children with USCP. Additionally, sensorimotor integration plays an important role in precision grip. In some children with USCP, the lesion that occurs in the brain can cause the CST to reorganize to the contralesional hemisphere. This results in the sensory and motor tracts in different hemispheres, impacting motor impairments. When this sensory-motor dissociation occurs or when there are successive lifts of an object with each hand, it is thought that the information is transferred through the corpus callosum (CC). However, damage to the CC can restrict somatosensory processing, which can further impair grasping abilities. Previous studies have only looked at precision grip impairments in relation to the CST. Therefore, an integrative approach is necessary to fully understand the mechanisms of precision grip impairments in children with USCP. In this study our aim was to examine the neural basis of precision grip in children with USCP. Twenty-seven children participated in an MRI assessment. This included the acquisition of structural and diffusion-weighted images (DWI) to extract diffusion metrics of the CST, DCML pathway, and CC. Children also participated in clinical sensory measures, including the stereognosis test, grating orientation task, and the two-point discrimination task. Additionally, children performed precision grip lifts using a custom-made object. All children were asked to grasp an object with interchangeable surfaces (i.e., sandpaper and rayon) to measure adaptation of grip force (GF) to object texture. They were also asked to grasp the same object, hold it in the air and slowly release their grip so that the object gradually slips from their fingertips. Twenty-seven children performed these tasks with their less affected hand, and 16 with their more affected hand. Additionally, 17 participants grasped an object with various weights with each lifting sequence consisting of lifting an object in succession with the same hand and then one lift with the contralateral hand. The results demonstrate the greater reduction of integrity (more damage) of the DCML pathway, the poorer the grasp task performance, as indicated through the safety margin (the difference between the minimum amount of force needed to prevent slipping and the applied grip force). Regression analyses and cluster analyses display that CST integrity and organization may also contribute to safety margin. This suggests that diffusion metrics of multiple pathways and CST organization when considered together contribute to grasping impairments in children with USCP. To assess this further, we examined the relative difference in the peak rate of force between objects with various weights during successive lifts with each hand. Children with USCP did demonstrate anticipatory control within hands and a generalization of anticipatory control between hands. However, a loss of the transfer information was shown when first grasping the object with their less affected hand and then their more affected hand, in children with an absent contralateral CST. Therefore, the results suggest precision grip impairments may not exclusively be due to sensory impairments, but instead how the sensory information is integrated with the motor output of the same hand.

Detta projekt var ett samarbete mellan Luleå tekniska universtiet och CranabSlagkraft och har behandlat ett förbättringsprojekt av befintliga inner- och yttergripklor med namnet E36 tillhörande skogsgrip CE360. Produkten hade en dåvarande konstruktionslösning som företaget länge inte har varit nöjd med. Klorna hade plåtar som svetsades fast på sidan av gripklorna för att skapa stabilitet. Utan dem skulle gripen inte ha tillräcklig hållfasthet då klorna skulle böjas och deformeras omgående vid användning. Sedan hade gripen även problem med stora nötningsproblem. Denna grip ville företaget förbättra då den var både ekonomisk kostsam och tidskrävande att bygga. Produkten var inte heller ekonomisk gynnsam för slutanvändarna då produkten hade så kort teknisk livslängd. Detta projekt har bearbetat dessa problem noggrant med grundlig analys på ett ingenjörsmässigt sätt som resulterat i en slutgiltig lösning med ett ritningsunderlag som har presenterats godkänts och byggdes till en prototyp under 2012. / This project was a collaboration between Luleå University of Technology and CranabSlagkraft and has addressed an improvement project of existing inner and outer gripc laws named E36 belonging to the forestry grip CE360. The product had a previous design solution that the company had long been dissatisfied with. The claws had plates welded to the sides of the grip claws to create stability. Without them, the grip would not have sufficient strength as the claws would bend and deform immediately during use. Furthermore, the grip also had significant wear issues. The company wanted to improve this grip as it was both economically costly and time-consuming to build. The product was also not economically beneficial for end-users as it had such a short technical lifespan. This project has meticulously addressed these problems with thorough analysis in an engineering manner, resulting in a final solution with a drawing basis that has been presented, approved, and built into a prototype in 2012.

This investigation was conducted to explore the between trial variability of the measures of the isometric peak force, time to peak force, area to peak force, area under the curve, slope (20%-80%), and the average slope of subjects assigned to perform a series of four isometric grip strength contractions and to develop a discriminant function equation that would predict group membership. Forty-nine college students were instructed to perform either a series of four maximal voluntary contractions (sincere) or a series of four submaximal (deceptive) contractions. The subjects were retested 24-48 hours after the initial test session. Data from both test sessions were recorded, displayed, and analyzed using segmental curve analysis. The coefficients of variation were computed for each test variable. The grand mean coefficient of variation for the sincere condition was .31 ± .02 compared to the grand mean coefficient of variation for the deceptive condition which was .77 ± .11 (p < .01). Coefficients of variation were used to predict group membership. The prediction equation accurately classified 92% of the sincere condition and 64% of the deceptive condition. / Master of Science