Abstract Introduction: The prevalence of anterior cruciate ligament tear is around 7000 every year within the swedish population and 95% of reconstructive surgery was with a hamstring tendon graft. Six months post surgery a 13% decrease in knee flexion strength compared to non injured side. The need for a study that determine the role of gastrocnemius and foot position in knee flexion is lacking in the litterature and could benefit Physiotheraphy ACL rehabilitation. Purpose: of his study was to investigate M gastrocnemius medialis (MGM) activation in the ipsilateral knee after removal of hamstring tendon for ACLR, and se if ankle position alter knee flexion outcomes. Method: 3 women, mean age 24 years who underwent ACL reconstruction with hamstring graft on one leg was tested. The time since injury was 3, 6 and 7 years respectively with an mean ,5 years wait until surgery. Isokinetic knee flexion and extension testing was done in the Biodex system 3 pro. EMG electrodes measured medial gastrocnemius activation with and without ankle in dorsiflexion. Results: Knee flexion peak strength was higher by a mean of 3 Nm (3,5%) with dorsiflexed foot. Mean (MGM) activation remained the same with or without dorsiflexion. Overall knee flexion strength was higher by a mean of 5 Nm compared to the injured side. Conclusion: Knee flexion in the biodex with foot in dorsiflexion could allow for isometric plantarflexion and increas power output. Certain changes in inclusion criteria and methodology as well more studies is needed to come to a given conclusion. / nej

Det finns idag ingen konsensus om den optimala rehabiliteringen efter en främre korsbandsrekonstruktion, vi vet heller inte idag huruvida rehabiliteringen ska specificeras efter parametrar som kön och ålder. Studien var en korrelerande tvärsnittsstudie med syfte att ta reda på om det förelåg någon skillnad i postoperativ lårmuskelstyrka 4-7 månader efter en korsbandsrekonstruktion med avseende på kön, ålder, skada och typ av operativt ingrepp. Av de 330 aktuella försökspersonerna var det endast 74 personer som godkänt deltagande och uppfyllde kraven för inklusionskriterierna. Försökspersonerna testades i en isokinetisk dynamometer(Biodex) för maximal styrka(60gr/s) och uthållig styrka(180gr/s). Resultaten presenterades genom ett Limb Symmetry Index. Studien fann inga signifikanta skillnader i de undersökta parametrarna mellan försökspersonerna i uppmätt lårmuskelstyrka mellan opererade och icke opererade benet. Detta tyder på att ålder och kön inte är avgörande vid initial rehabilitering avseende post operativ lårmuskelstyrka.

Bakgrund: I dagens längdskidåkning har stakningen utvecklats till att bli en avgörande komponent till att prestera framgångsrikt, framförallt inom sprintåkningen där de höga hastigheterna ställer stora krav på överkroppsstyrka. Bålens styrka bör därför testas för att planera och utvärdera träning vilket endast sker genom statiska och uthållighetbaserade övningar som inte är speciellt idrottsspecifika. Ett isokinetiskt bålstyrkettest för elitskidåkare saknas i dagsläget men med Biodex System 3 är det möjligt att utveckla. Syftet med studien var att ta fram ett testprotokoll för isokinetisk bålstyrka i Biodex och analysera sambandet mellan isokinetisk, isometrisk och explosiv bålstyrka samt ställa resultatet mot FIS-punkter i sprint. Metod: Elva elitskidåkare deltog i studien där de efter ett testbatteri med explosiva och statiska styrketester genomförde ett isokinetiskt bålstyrketest i Biodex. I testet skulle forskningspersonerna fastspända i sittande position producera maximal koncentrisk kraft i 50-90° höftflexion under sex repetitioner under en standardiserad hastighet på 60° per sekund. Datat analyserades med Spearmans korrelationskoefficient (r) och signifikansvärdet var: p <0,05.  Resultat: Ett starkt positivt samband (r=0,79, p <0,05) fanns mellan det isokinetiska bålstyrketestet (Biodexₘₐₓ) och det isometriska bålstyrketestet (Isobålₘₐₓ). För de manliga åkarna påvisades ett starkt positivt samband mellan Biodexₘₐₓ och FIS-punkter i sprint (r=0.89, p<0.05) samt Biodexₘₐₓ och vikt (r=0,92 p <0,05). Inga fler statistiskt signifikanta samband kunde påvisas. Konklusion: Studien visar att det finns ett tydligt samband mellan Biodexₘₐₓ och Isobålₘₐₓ samt Biodexₘₐₓ och vikt bland män. Ingen signifikant koppling mellan Biodexₘₐₓ och bollkastet samt Biodexₘₐₓ och längd bland män kunde hittas. Sambandet mellan Biodexₘₐₓ och FIS-punkter i sprint bland män visar att högt resultat i biodextestet tyder på sämre prestationsförmåga i sprint. Inga stora slutsatser kan dras från resultatet på grund av för lågt deltagarantal. Däremot kan isokinetisk bålstyrka nu testas i Biodex och bidra till framtida forskning. / Backgrund: Double poling has developed into a crucial component for cross country skiing performance, especially in sprint where high velocities place great demands on upper body strength. Core strength should therefore be tested to evaluate training which only occurs through static and endurance-based exercises that are not particularly sports-specific. An isokinetic core strength test for elite skiers is currently not available but the Biodex System 3 makes it possible to develop. The purpose of the present study was to develop a protocol for isokinetic core strength and analyze the relationship between isokinetic, isometric and explosive core strength and also compare the result to FIS-points in sprint.  Method: Eleven cross country skiers participated in the study where they after a set of explosive and static tests completed an isokinetic core strength test in the Biodex. The subjects were strapped to the Biodex into a sitting position where they produced maximum concentric force in 50-90° hip flexion during six repetitions at a standardized speed of 60° per second. The data was analysed with Spearman korrelationskoeffizient (r) och the level of significance was: p <0,05. Result: A strong positive relationship (r=0,79, p <0,05) was found between the isokinetic core strength test (Biodexₘₐₓ) and the isometric core strength test (Isobålₘₐₓ). For male skiers a strong positive relationship was found between Biodexₘₐₓ and FIS-point in sprint (r=0.89, p<0.05) and Biodexₘₐₓ and weight (r=0,92 p <0,05). No more statistically significant results were observed. Conclusion: This study shows a strong relationship between Biodexₘₐₓ against Isobålₘₐₓ and Biodexₘₐₓ and weight among men. No statistically significant connection was found between Biodexₘₐₓ and the ball throw and Biodexₘₐₓ and length among men. The relationship between Biodexₘₐₓ and FIS-points in sprint among men indicates that high values in the Biodex means a decreased performance in sprint. No major conclusions can be made from the results due to the low numbers of participants. However, isokinetic core strength can now be tested in the Biodex and contribute to future recherch.

This project investigated the effects of Kinesio® Tape on pain, kinesiophobia, and proprioception in participants with patellar tendonitis. Thirty participants with patellar tendonitis were divided into three groups, the first received a supportive Kinesio® Tape application at the knee, the second received a facilitative application at the hip, and the third received both. A Visual Analog Score, Tampa Scale for Kinesiophobia score, and a proprioceptive score quantified through the Biodex Balance System were obtained both immediately after application, and 24 to 36 hours following. Statistically significant improvement in VAS scores and in proprioceptive ability with eyes closed 24 to 36 hours following Kinesio® Tape application was observed under all interventions. Kinesio® Tape application for pain, cause of pain and proprioception may assist patients with patellar tendonitis.

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The shoulder is one of the most complex joints in the body. It has a large range of motion and has active, as well as passive, components to its stabilization. Many injuries occur every year due to overexertion and strain on the shoulder. Musculoskeletal models can be used as a proactive ergonomics tool for shoulder specific job task design, and to help prevent these injuries before they occur. The purpose of this thesis was to critically evaluate the performance of four optimization criteria (sum of squared activation, sum of cubed activation, sum of quartic activation, and entropy assisted) using the open source modeling platform OpenSIM. Experimental torque, kinematic, and EMG data were collected using ten participants for a variety of dynamic arm movements, and static arm postures, in different planes of action. The kinematic and torque data were processed and used as inputs to OpenSIM to calculate predicted muscle activations and joint reaction forces. Experimental EMG was cross correlated with the predicted muscle activity of 8 muscles, and RMSD was calculated between experimental and predicted muscle activity for evaluation. A co-contraction index was also used to assess the model’s ability to predict co-activation between muscle pairs. Overall, the sum of cubed activation and sum of quartic activation model predictions explained significantly more variance (38 ±2.5%, p<0.01) than the sum of squares and entropy models, when compared with experimental EMG. In conclusion, the type of optimization criterion chosen had an effect on the accuracy of the model predictions. Future research, in the development of optimization criterions for the shoulder, will create better model predictions of muscle forces and joint reaction forces, enabling musculoskeletal models to be more useful as a tool to the clinical and ergonomic populations. / Thesis / Master of Science (MSc) / The shoulder is one of the most complex joints in the body. It has a large range of motion and has muscles and ligaments to support the stability of the complex. Many injuries occur every year due to overexertion and strain on the shoulder. Proactively modelling can help reduce these injuries by evaluating a job's likelihood to injure a worker before the worker does the job. The purpose of this thesis was to evaluate the performance of several different shoulder models. Experimental torque, kinematic, and EMG data were collected using ten participants for a variety of dynamic arm movements, and static arm postures, in different planes of action. The kinematic and torque data were used by the model to predict muscle activations and joint reaction forces. Experimental EMG was cross correlated with the predicted muscle activity of 8 muscles, and RMSD was calculated between experimental and predicted muscle activity for evaluation. A co-contraction index was also used to assess the model’s ability to predict co-activation between muscle pairs. Overall, the sum of cubed activation and sum of quartic activation model predictions explained significantly more variance (38 ±2.5%, p<0.01) than the sum of squares and entropy models, when compared with experimental EMG. In conclusion, the type of model chosen had an effect on the accuracy of the model predictions. Future research, in the development of optimization criterions for shoulder models, will create better model predictions of muscle forces and joint reaction forces, enabling musculoskeletal models to be more useful as a tool to the clinical and ergonomic populations.

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