Sammanfattning Fotboll är världens mest utövad idrott och korsbandsskador är vanliga inom fotboll där kvinnor har en markant ökad risk jämfört med män att skada sig. Dessa skador medför ofta lång tids frånvaro från idrottande och är kostsamma för både individ och samhälle. Det är därför viktigt att undersöka hur dessa skador kan förhindras. Syfte och frågeställningar: Denna studie har utförts med syftet att kritiskt granska och jämföra träningsprogram för prevention av främre korsbandsskada för kvinnliga fotbollsspelare. Studien har två frågeställningar: Ger ett preventivt träningsprogram för kvinnliga fotbollsspelare en minskad incidens av främre korsbandsskador? Finns det evidens för vilket av träningsprogrammen är bäst? Studiens hypotes är att preventionsträning minskar incidensen av främre korsbandsskador hos kvinnliga fotbollsspelare. Metod: Det är en litteraturstudie. Litteratursökning genomfördes på PubMed februari-maj 2016. Nio original studier som kvalificerades utifrån inklusions- och exklusionskriterierna hittades. Information blev hämtad från varje enskild studie för att jämföra studierna, räkna fram den totala effekten av preventionsprogrammen samt riskreduction ration (RRR) och number needed to treat (NNT). Resultat: Resultatet stämmer överens med studiens hypotes. Den sammanlagda riskreduceringen av preventionsträningen mättes 69,3%. Tre av nio studier visade signifikant minskad incidens av främre korsbandsskador. Skillnaden i studiernas design, kvalitet och styrka gör det svårt att avgöra vilket av programmen är bäst. Slutsats: Det finns evidens för att preventiva träningsprogram kan ge minskad incidens av främre korsbandsskador. Fler studier av bra kvalitet behövs för att studera riskfaktorer samt vilka övningar som kan påverka dessa för att kunna skapa optimala träningsprogram. / <p>Kurs Idrott III vt 2016</p>

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The anterior cruciate ligament (ACL) is a major ligament within the knee joint. Its role is to provide stability and maintain the physiological kinetics and kinematics of the joint. ACL injuries are common as a result of sporting and traffic accidents and current therapeutic options do not fully restore the joint kinetics and kinematics. As such, patients often suffer from increased joint laxity and joint pain following an ACL reconstruction and this can lead to secondary problems such as osteoarthritis. It is believed that improving the ACL graft could help restore the normal kinetics and kinematics of the knee joint and hence postpone or prevent the onset of primary and secondary problems. Tissue engineering has the potential to provide functional tissue to repair or replace injured or diseased tissues in the patient. The ACL is a tissue which could benefit from such developments and thus improve the success of the reconstruction. However, the ACl is a complex structure made up of a highly orientated collagen hierarchy which experiences three dimensional loading in vivo. For an engineered tissue to be functional it is necessary for this orientated structure to be replicated. The appropriate structure is achieved by replication of the in vivo ACL strain pattern which requires combined tensile and torsional loading. Current custommade and commercially available bioreactors have not been able to fully replicate this motion with the necessary feedback and monitoring of mechanical parameters. The aim of this project was to develop a novel bioreactor with physiological mechanical conditioning for the tissue engineering of an anterior cruciate ligament. A bioreactor capable of applying complex tensile and torsional loading to a developing ACL was designed, manufactured and validated. The bioreactor which has been developed is a novel research tool which allows the effect of a number of parameters to be investigated in a 3D loading environment. It can be used for the engineering of connective tissues such as ligaments and tendons and has the potential to be adapted for use with other musculoskeletal tissues such as bone. It could also be used for research to understand the processes involved in the growth and development of tissues.

Despite the higher incidence of anterior cruciate ligament injuries in pediatric female populations, limited research has investigated sex-differences in youth biomechanics. Furthermore, research involving jump mechanics typically requires participant to follow a set protocol, such as sticking the landing. To reduce variability and improve reliability, trails where participants fail to meet the required protocol are discarded; however, significant clinical findings may be elucidated from these trials. The purpose of this thesis was to provide a complete biomechanical analysis of unanticipated single-leg drop-jump landings in youth athletes. Thirty-two healthy youth athletes completed unanticipated single-leg drop-jump landings on their dominant limb. Trials where participants shifted foot position or touched the ground with the contralateral leg were categorized as failed. Drop-jump landings were time-normalized using landmarks within the drop-jump task. Statistical parametric mapping (SPM) determined time-varying sex-differences in muscle onset time, co-activation, kinematics and kinetics. Wilcoxon signed-rank tests and paired sample t-tests compared lower-limb kinematics, centre-of-mass excursion and muscle activation amplitudes during the successful and failed landings. A logistic regression model was also fit to predict the likelihood of a successful landing. SPM identified significantly greater trunk flexion angle in males during the deceleration, flight, and landing phase of the drop-jump. Greater quadriceps-gastrocnemius co-activation was identified during the flight phase in female participants and independent sample t-test identified longer muscle onset time in the vastus lateralis of male participants. When comparing failed and successful landings greater hip abduction and less external rotation angles were observed during the successful trials. In addition, greater preparatory muscle activation was observed in the rectus femoris and semitendinosus during the flight phase of the failed landings. A logistic regression model, which included eight kinematic and neuromuscular variables, offered a training classification accuracy of 70% and a leave-one-out cross-validation accuracy of 65%. In conclusion, females land in a more erect posture and may be less effective at dissipating landing forces. In addition, greater co-activation and shorter pre-activations of the lower limb musculature may indicate a less effective muscle activation strategy in females. Furthermore, hip kinematics and the surrounding musculature play an important role in controlling successful and failed unanticipated landings. The variables included in the logistic regression model indicate which key factors are linked to landing a jump successfully. Training modalities aimed at improving landing mechanics should therefore focus on modifying these variables.

Background: Epidemiological studies have demonstrated higher ACL injury rates in female athletes when compared to males involved in the same sport. A recent meta-analysis of ACL injury prevention programs found that technique training was a common component of programs that were successful in reducing ACL injury. Purpose: The primary purpose was to determine the immediate and long-term effects of technique training aimed at minimizing medial knee displacement during jump-landings in female recreational athletes. The secondary purpose was to determine if any transfer of skill occurred as a result of our technique training. Study Design: Controlled laboratory study. Methods: A total of 26 participants who presented with medial knee displacement during a basketball rebound screening task completed the study protocol. Participants were randomly assigned to two groups (experimental and control groups, 13 each). The experimental groups received jump landing instructions aimed at minimizing medial knee displacement. The control group received "sham" training consisting of jump training for maximum height. Baseline motion analyses of participants performing a basketball rebound task were performed prior to participants receiving technique training. Immediate and delayed retentions tests were performed after the initial instructional session and after home-based training. Additionally, motion analyses were also performed on a stop-jump task during the baseline assessment and the delayed retention test to help in determining if any transfer occurred. Results: The initial instructional session resulted in increased knee excursion and reduced peak knee adduction moments in the experimental group. Following home-based training, the experimental group continued to exhibit increased knee excursion along with decreased landing forces. No evidence of transfer was present following the initial training session or after home-based training. Conclusion: Our jump training instructions led to temporary changes, most notably increased knee excursion about the sagittal plane. No transfer of skill occurred as a result of our training. Clinical Relevance: Technique training instructions aimed at reducing medial knee displacement resulted in increased sagittal plane motion, but were unable to minimize medial knee displacement. ACL injury prevention programs may need to include a variety of drills, tasks, and sport-specific movements.

Firewalls are an integral part of network security. They are pervasive throughout networks and can be found in mobile phones, workstations, servers, switches, routers, and standalone network devices. Their primary responsibility is to track and discard unauthorized network traffic, and may be implemented using costly special purpose hardware to flexible inexpensive software running on commodity hardware. The most basic action of a firewall is to match packets against a set of rules in an Access Control List (ACL) to determine whether they should be allowed or denied access to a network or resource. By design, traditional firewalls must sequentially search through the ACL table, leading to increasing latencies as the number of entries in the table increase. This is particularly true for software firewalls implemented in commodity server hardware. Reducing latency in software firewalls may enable them to replace hardware firewalls in certain applications. In this thesis, we propose a software firewall architecture which removes the sequential ACL lookup from the critical path and thus decreases the latency per packet in the common case. To accomplish this we implement a Bloom filter-based, stochastic pre-classification stage, enabling the bifurcation of the predicted good and predicted bad packet code paths, greatly improving performance. Our proposed architecture improves firewall performance 67% to 92% under anonymized trace based workloads from CAIDA servers. While our approach has the possibility of incorrectly classifying a small subset of bad packets as good, we show that these holes are neither predictable nor permanent, leading to a vanishingly small probability of firewall penetration.

The knee is one of the most complex joints in the body, relying entirely on ligaments and muscles for stabilization. With the rise in people participating in sports, including a significant increase in female athletes, the prevalence of anterior cruciate ligament (ACL) injuries is very evident. With recent research showing that ACL injuries lead to osteoarthritis 10-20 years after the injury, determining the cause of these injuries to be able to prevent them is crucial. To date, both in-vivo and in-vitro techniques have been used to analyze the influences of the ACL injury including neuromuscular, anatomical, and kinematic. In-vivo techniques used to investigate knee kinematics is limited by the inability to take real ACL strain measurements while in-vitro techniques used to investigate anatomical considerations is limited by the inability to apply true muscular and kinematic forces. The purpose of the present thesis is to show the design and validation of a dynamic knee injury simulator. The simulator puts a cadaver knee, original ligaments and patellar tendon still attached, through motions which put the ACL at a high-risk of injury with realistic influence of muscles. The muscular influences are applied with actuators pulling the same force pro les as natural muscles. To get realistic muscle pro files, Anybody Software is used. Anybody Software is a modeling software which puts a skeletal system through prescribed motions and using an optimization algorithm calculates the muscle force pro file. The motion of the knee in the sagittal plane is simulated with actuators. The simulator consists of four actuators which are used in force control mode to add the muscle influence to the knee. Another two belt actuators are used for the joint motions, one each for the hip and ankle. The hip will move along the resultant Z motion and the ankle will move along the resultant Y motion. Simple gait is used for initial validation, the actuators chosen have speed and force capabilities for high-risk motions. The gait was successfully simulated and muscle force versus time profi le tracked the input well. The regression coeffcient study shows very good comparison. The hamstring muscle group is the only one which does not show very good comparison however this is only due to the jumpy nature of the hamstring profi le. The ACL strain fell within a similar range to published gait ACL strain data. The validation was successful, and with greater available force and speeds in the actuators, showing the use of this simulator during high-risk motions is possible.

The knee is one of the most complex joints in the body, relying entirely on ligaments and muscles for stabilization. With the rise in people participating in sports, including a significant increase in female athletes, the prevalence of anterior cruciate ligament (ACL) injuries is very evident. With recent research showing that ACL injuries lead to osteoarthritis 10-20 years after the injury, determining the cause of these injuries to be able to prevent them is crucial. To date, both in-vivo and in-vitro techniques have been used to analyze the influences of the ACL injury including neuromuscular, anatomical, and kinematic. In-vivo techniques used to investigate knee kinematics is limited by the inability to take real ACL strain measurements while in-vitro techniques used to investigate anatomical considerations is limited by the inability to apply true muscular and kinematic forces. The purpose of the present thesis is to show the design and validation of a dynamic knee injury simulator. The simulator puts a cadaver knee, original ligaments and patellar tendon still attached, through motions which put the ACL at a high-risk of injury with realistic influence of muscles. The muscular influences are applied with actuators pulling the same force pro les as natural muscles. To get realistic muscle pro files, Anybody Software is used. Anybody Software is a modeling software which puts a skeletal system through prescribed motions and using an optimization algorithm calculates the muscle force pro file. The motion of the knee in the sagittal plane is simulated with actuators. The simulator consists of four actuators which are used in force control mode to add the muscle influence to the knee. Another two belt actuators are used for the joint motions, one each for the hip and ankle. The hip will move along the resultant Z motion and the ankle will move along the resultant Y motion. Simple gait is used for initial validation, the actuators chosen have speed and force capabilities for high-risk motions. The gait was successfully simulated and muscle force versus time profi le tracked the input well. The regression coeffcient study shows very good comparison. The hamstring muscle group is the only one which does not show very good comparison however this is only due to the jumpy nature of the hamstring profi le. The ACL strain fell within a similar range to published gait ACL strain data. The validation was successful, and with greater available force and speeds in the actuators, showing the use of this simulator during high-risk motions is possible.

Många främre korsbandsskadade idrottare upplever efter operation en nedsatt tillit till knäet och är rädda för nya skador. Detta kan resultera i försämrad rehabilitering. Det är därför viktigt att kunna identifiera dessa patienter. Syfte: Syftet med den här studien var att klargöra i vilken utsträckning trippelhoppet, cross over-hoppet och sidohoppet avspeglar vilken tillit till knäet den korsbandsopererade patienten upplever 6-12 månader efter operation i samband med återgång till idrott. Metod: Urvalet bestod av 9 kvinnor och 9 män patienter som genomgått främre korsbandsrekonstruktion och som 6-12 månader efter det var på väg tillbaka till idrott. Deltagarna genomförde tre funktionella tester, trippelhoppet, cross over-hoppet och sidohoppet på sitt ickeopererat respektive på sitt opererade ben. Före varje hopptest skattades på en visuell analog skala ( VAS-skala) graden av tillit till knäet inför hoppet och graden av förmåga att ta i efter hoppet. Deltagarna fyllde även i självskattningsformuläret Knee Self-Efficacy Scale (K-SES). Resultat: Signifikanta skillnader mellan opererat och ickeopererat ben sågs framför allt i tilliten till knäet inför trippelhoppet och cross over-hoppet. Mindre, men dock signifikanta sidoskillnader sågs även i tilliten till knäet inför sidohoppet och i skattad förmåga att ta i efter alla tre hoppen. Signifikanta sidoskillnader i hoppresultat sågs endast i trippelhoppet och cross over-hoppet. De enda limb symmetri index ( LSI)-värden som var onormala (&lt;90%), var dem vid skattad tillit till knäet i trippelhoppet och cross over-hoppet. Det fanns en korrelation mellan LSI för skattad tillit till knäet inför trippelhoppet och cross over-hoppet och K-SESPresent och K-SESFuture. I trippelhoppet fanns även en korrelation mellan LSI för hoppresultat och skattad förmåga att ta i och K-SESPresent. Slutsats: I trippelhoppet och cross over-hoppet är sidoskillnaden i skattad tillit till knäet betydligt större än vad sidoskillnaden i hoppresultat och skattad förmåga att ta i vid hoppen är. LSI vid skattad tillit i dessa hopp korrelerar väl med tilltron till sin förmåga i K-SES båda delskalor. Trippelhoppet och cross over-hoppet i kombination med VAS-skattning av tillit till knäet inför hoppet samt skattning av förmågan att ta i efter hoppet skulle kunna lämpa sig väl vid utvärdering av vilken tillit till det korsbandsopererade knäet patienten upplever under rehabiliteringstiden. / Abstract Many ACL-injured athletes experience after surgery a reduced reliance on the knee and are afraid of new lesions. It is therefore important to identify those patients. Aim: The aim with this study was was to establish whether the triple hop, the cross over hop and the side hop really shows the ACL reconstructed patient´s confidence in the knee 6-12 months post operatively when returning to sport. Method: 9 women and 9 men who had undergone ACL reconstruction 6-12 months previously and were about to return to sports, were included in this study. The participants conducted three functional single leg hop tests in both legs; the triple hop, the cross over hop and the side hop test. Before each specific hop test, the confidence in the knee was estimated and directly efter the hop test, the degree of ability to use their strength was estimated on a visual analog scale. The subjects were also asked to fill out the Knee Self- Efficacy Scale (K-SES) form. Results: Significant differences were found in the ACL reconstructed knee compared to the other knee, when estimating amount of confidence the patient had to his knee before performing the triple hop and the cross over hop. Some significance was also found regarding the reliance on the knee estimated before the side hop and also when estimating the ability use their strength in all three hop tests. Only the triple hop and cross over hop, showed significant result. The only abnormal limb symmetri index (LSI)-value found (&lt;90%), was that of estimated confidence before the triple hop and the cross over hop. A correlation was found for LSI when estimated confidence in the knee before the triple hop and the cross over hop and the K-SESPresent and K-SESFuture. The triple hop also correlated with LSI hop result and estimated ability to use their strength and for the K-SESPresent. Conclusion: The triple hop and the cross over hop show a greater difference in estimated confidence in the knee than does the difference in hop results and estimated ability to use their strength when jumping. The LSI-value of estimated confidence in these two hop tests, correlates well with self efficacy for both the K-SES scales. The triple hop and the cross over hop, in combination with estimated confidence and ability to use their strength while jumping using a visual analog scale, could be well suited for evaluating the confidence in the ACL knee surgery patient experience during the rehabilitation period.

Joint movements are essential for the function of human body during the activities of daily living and sports. The movement of human joints varies from normal to those which have an increased range of joint movement (gymnasts) to those with extreme disabling laxity in patients with a connective tissue disorder (Ehlers Danlos Syndrome). “Hypermobility" is most commonly used to describe excessive movement. Hypermobility was assessed by using the current criteria of the Beighton score for signs and the Brighton criteria for symptoms of hypermobility in a group of orthopaedic patients attending the specialist knee and shoulder injury clinics. The Beighton score was found to be higher in patients attending for primary ACL reconstruction (mean 2.9, p = 0.002) and revision ACL reconstruction (mean 4, p < 0.001) when compared with the control group. Hypermobility was a risk factor for the failure of ACL reconstruction (30% vs 0%). The mean Beighton score was higher in both the primary shoulder dislocation group (mean difference 1.8, p=0.001) and the recurrent shoulder dislocation group (mean difference 1.4, p=0.004). Bone defects were studied on the CT scan following shoulder dislocations. There was no correlation between hypermobility and the bone defects. The bone defect was a risk factor for recurrent shoulder instability (48% vs 16%). A material testing system was used to assess the tissue laxity of discarded hamstring tendon and shoulder capsule obtained during stabilisation procedures. The mean gradient of slope for both tendon and capsule graphs was 23.8 (range 3.08-52.63). The tissue laxity was compared to the Beighton score, however no correlation was detected between the Beighton score and the gradient of the tissue laxity. An electronic goniometer was used to measure the angle of the MCP joint of the little finger, whilst a force plate system simultaneously measured the force required to hyperextend the MCP joint. The little finger MCP joints of each hand were assessed in this manner in a group of patients undergoing primary ACL reconstruction or open shoulder stabilization. The mean force required to produce the 40 degrees angle at the little finger MCP joint was 0.04 kg with a range from 0-0.11 kg. There was a positive correlation between the gradient of tissue laxity and the force required to produce 40 degrees angle at the little finger of the dominant hand. The expression of Collagen V and Small leucine rich proteoglycans (Decorin and Biglycan) was studied in the skin, hamstring tendon and shoulder capsule of the patients described above attending with shoulder or knee instability. These patients had different levels of hypermobility (as assessed by the Beighton score) and symptoms of hypermobility (as assessed by the Brighton criteria to diagnose Benign Joint Hypermobility Syndrome). The weaker tendon group was found to have a lower mean Beighton score, while the weaker skin group had a higher mean Beighton score. Collagen V expression was higher in the skin dermal papillae of the weaker group. The Beighton Scores were higher in patients with ACL and shoulder injuries. Hypermobility was a risk factor for the failure of ACL reconstruction. There was no correlation between hypermobility and the bone defects on the CT scan following shoulder dislocation. Bone defects were a risk factor for recurrence. There was no correlation between the Beighton Score and the tissue laxity. There was a correlation between the tissue laxity and the clinical assessment of laxity at the little finger MCPJ by using a force- goniometer system. There was a correlation between the collagen V expression in the dermal papillae of the skin and the Beighton score.