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This research explores the red light running phenomena and offer a better understanding of the factors associated with it. The red light running is a type of traffic violation that can lead to angle crash and the most common counter measure is installing a red light running cameras. Red light running cameras some time can reduce the rates of red light running but because of the increased worry of the public towards crossing the intersection it can cause an increase in rear end crashes. Also the public opinion of the red light running cameras is that they are a revenue generator for the local counties and not a concern of public safety. Further more, they consider this type of enforcement as violation of privacy. There was two ways to collect the data needed for the research. One way is through a tripod cameras setup temporarily placed at the intersection. This setup can collect individual vehicles caught in the change phase with specific information about their reactions and conditions. This required extensive manual analysis for the recorded videos plus data could not be collected during adverse weather conditions. The second way was using traffic monitoring cameras permanently located at the site to collect red light running information and the simultaneous traffic conditions. This system offered more extensive information since the cameras monitor the traffic 24/7 collecting data directly. On the other hand this system lacked the ability to identify the circumstances associated with individual red light running incidents. The research team finally decided to use the two methods to study the red light running phenomena aiming to combine the benefits of the two systems. During the research the team conducted an experiment to test a red light running countermeasure in the field and evaluate the public reaction and usage of this countermeasure. The marking was previously tested in a driving simulator and proved to be successful in helping the drivers make better stop/go decisions thus reducing red light running rates without increasing the rear-end crashes. The experiment was divided into three phases; before marking installation called "before", after marking installation called "after", and following a media campaign designed to inform the public about the use of the marking the third phase called "after media" The behavior study that aimed at analyzing the motorist reactions toward the signal change interval identified factors which contributed to red light running. There important factors were: distance from the stop bar, speed of traffic, leading or following in the traffic, vehicle type. It was found that a driver is more likely to run red light following another vehicle in the intersection. Also the speeding vehicles can clear the intersection faster thus got less involved in red light running violations. The proposed "Signal Ahead" marking was found to have a very good potential as a red light running counter measure. The red light running rates in the test intersection dropped from 53 RLR/hr/1000veh for the "before" phase, to 24 RLR/hr/1000veh for the "after media" phase. The marking after media analysis period found that the marking can help the driver make stop/go decision as the dilemma zone decreased by 50 ft between the "before" and the "after media" periods. Analysis of the traffic condition associated with the red light running it revealed that relation between the traffic conditions and the red light running is non-linear, with some interactions between factors. The most important factors included in the model were: traffic volume, average speed of traffic, the percentage of green time, the percentage of heavy vehicles, the interaction between traffic volume and percentage of heavy vehicles. The most interesting finding was the interaction between the volume and the percent of heavy vehicles. As the volume increased the effect of the heavy vehicles reversed from reducing the red light running to increasing the red light. This finding may be attributed to the sight blocking that happens when a driver of a passenger car follows a larger heavy vehicle, and can be also explained by the potential frustration experienced by the motorist resulting from driving behind a bigger vehicle.

Marathon runners are prone to femoral stress fractures due to the high magnitudes and frequencies of lower extremity loads during training. Female runners tend to have a greater incidence of stress fracture compared to male runners. Sex-specific differences in body structure, joint pressure, and muscle activation patterns that influence bone remodeling may cause this observed difference in stress fracture occurrence. The goal of this thesis was to develop a finite element model of the femur during marathon training, then determine if marathon training affected bone properties of male and female runners differently. To achieve this goal, a finite element femur model was integrated with a bone remodeling algorithm. Sex-specific muscle and joint pressure loads corresponding to baseline activity and marathon training were applied to the finite element femur model. Axial strain, density, damage, and remodeling activity were quantified at regions predicted to be at high risk of stress fracture. The major results of this analysis predicted that marathon training increased bone damage at all regions of interest in both males and females, especially at the inferior neck. The model predicted that the superior neck, trochanter, and proximal diaphysis were more severely weakened in females than males after marathon training. While this model cannot directly quantify femoral stress fracture risk, it may be used to predict regions of bone weakness in male and female marathon runners. Future work may be done to improve accuracy of this model by using sex-specific femur geometry and bone remodeling parameters specific to male and female marathon runners. This model may be useful in future applications to study effectiveness of injury preventive methods, such as gait retraining, in reducing bone damage.

The forefoot (FF) running pattern has been recently advocated to improve running economy and prevent overuse injuries compared to the rearfoot (RF) pattern. However, these claims have not been supported by empirical evidence. The purpose of this dissertation was to investigate the potential advantages of RF and FF patterns to improve running economy and reduce injury risk in 20 natural RF and 20 natural FF runners. The first study found that the RF group was more economical when performing the RF pattern at a slow, medium, and fast speed vs. FF running. Only running at the fast speed resulted in a difference in economy between footfall patterns in the FF group in which RF running was more economical. Therefore, there is no advantage of FF running for improving running economy. The results of the second study indicated that there was a weak to moderate relationship between Achilles tendon (AT) moment arm length and running with either RF or FF patterns. AT force was greater during FF running, which may increase the risk of developing tendon injury. The third study used a modeling approach to find that FF running resulted in greater elastic energy recoil in the gastrocnemius (GA) and the soleus (SO). However, greater mechanical work overall with FF running resulted in no difference in metabolic cost of the GA between footfall patterns but greater metabolic cost of the SO compared to RF running. The fourth study found that shock attenuation was greater during RF running compared to FF running. Greater shock attenuation during RF running was a result of an increased load imposed on the system. Decomposing the vertical ground reaction force in the frequency domain revealed that RF running may have a greater reliance on passive shock attenuation mechanism whereas the FF pattern may have a greater reliance on active shock attenuation mechanisms. These results suggest that previous speculation that the FF running pattern is more economical was not substantiated. It is likely that each footfall pattern exposes a runner to different types of injuries, rather than one footfall pattern being more injurious than another.

Carbody tilting is today a mature and inexpensive technology allowing higher speeds in curves and thus reduced travel time. The technology is accepted by most train operators, but a limited set of issues still holding back the full potential of tilting trains. The present study identifies and report on these issues in the first of two parts in this thesis. The second part is dedicated to analysis of some of the identified issues. The first part contains Chapters 2 to 5 and the second Chapters 6 to 12 where also the conclusions of the present study are given. Chapters 2 and 3 are related to the tilting train and the interaction between track and vehicle. Cross-wind stability is identified as critical for high-speed tilting trains. Limitation of the permissible speed in curves at high speed may be needed, reducing the benefit of tilting trains at very high speed. Track shift forces can also be safety critical for tilting vehicles at high speed. An improved track standard must be considered for high speed curving. Chapters 4 and 5 cover motion sickness knowledge, which may be important for the competitiveness of tilting trains. However, reduced risk of motion sickness may be contradictory to comfort in a traditional sense, one aspect can not be considered without also considering the other. One pure motion is not the likely cause to the motion sickness experienced in motion trains. A combination of motions is much more provocative and much more likely the cause. It is also likely that head rotations contribute as these may be performed at much higher motion amplitudes than performed by the train. Chapter 6 deals with services suitable for tilting trains. An analysis shows relations between cant deficiency, top speed, tractive performance and running times for a tilting train. About 9% running time may be gained on the Swedish line Stockholm – Gothenburg (457 km) if cant deficiency, top speed and tractive performance are improved compared with existing tilting trains. One interesting conclusion is that a non-tilting very high-speed train (280 km/h) will have longer running times than a tilting train with today’s maximum speed and tractive power. This statement is independent of top speed and tractive power of the non-tilting vehicle. Chapters 7 to 9 describe motion sickness tests made on-track within the EU-funded research project Fast And Comfortable Trains (FACT). An analysis is made showing correlation between vertical acceleration and motion sickness. However, vertical acceleration could not be pointed out as the cause to motion sickness as the correlation between vertical acceleration and several other motions are strong. Chapter 10 reports on design of track geometry. Guidelines for design of track cant are given optimising the counteracting requirements on comfort in non-tilting trains and risk of motion sickness in tilting trains. The guidelines are finally compared with the applied track cant on the Swedish line Stockholm – Gothenburg. Also transition curves and vertical track geometry are shortly discussed. Chapters 11 and 12 discusses the analysis, draws conclusions on the findings and gives proposals of further research within the present area. / QC 20101119

There has been a prevalence of long-distance running footwear incorporating carbon-fiber plates within their midsoles, effectively increasing their longitudinal bending stiffness (LBS). This modification of modern racing footwear has occurred concurrently with large improvements in running times (Bermon et al., 2021), putting into question how these footwear components affect performance (Muniz-Pardos et al., 2021). The current literature has investigated this at level running, but with the increasing popularity of trail running, it is of interest to investigate whether the benefits found during level running translate to graded running. Therefore, the overall aim of this study was to investigate the effects of increased footwear midsole longitudinal bending stiffness (i.e. carbon-fiber plates) on running energetics and biomechanics at various inclines. The effects of high LBS (Nike Vaporfly 4% with midsole intact) and low LBS (Nike Vaporfly 4% with mediolateral cuts made at the forefoot of the midsole through the carbon-fiber plate) footwear conditions were compared for running at 0°, 6°, and 12° inclines. Running energetics and biomechanics data were quantified by measuring metabolic rate and lower leg joint mechanics (from motion capture and ground reaction force measurements). Results from this study suggest that increasing longitudinal bending stiffness within the footwear midsoles has limited influence on running energetics (small non-significant improvements of metabolic power at all inclines), but has considerable effects on the biomechanics of the ankle and MTP joints. However, the most important between shoe differences were independent of grade, suggesting that the benefits of modern racing shoe observed for level running can be expected to translate to steep uphill running. Nevertheless, it should be noted that this study was only able to collect and use data for analysis from a limited number of participants (n=7), and therefore is underpowered, so there may be significant differences that go undetected

Background: In recent years, sudden improvements in long-distance running performance have been suggested to be due to the latest technological innovations in running footwear. However, inter-individual differences appear to be large in the performance enhancing effect these shoes elicit where some runners experience a decline in performance while others improve substantially. The reason for this is not yet fully understood but may be due to differences in anthropometric and neuromuscular characteristics between runners. Aim: The aim of this thesis was to investigate the association between individual anthropometrical and neuromuscular characteristics of runners with changes in running mechanics while wearing these new generation shoes. Method: Eight male endurance runners performed four different testing protocols during one single visit. These consisted of an anthropometrical protocol where measurements of height, weight, leg length and Achilles tendon moment arm length were determined; a jumping protocol where vertical stiffness and eccentric utilization ratio (EUR) were recorded using a force platform; a running protocol where contact time, step length, ankle propulsive power and knee absorption power were measured using a force platform and a 12-camera motion analysis system; and finally a force-velocity protocol where each participant performed calf raises and back squats with incremental loads in a smith machine while barbell velocity was simultaneously recorded. The collected data were then statistically analyzed using Wilcoxon Signed-Rank Test and Spearman’s Rank Correlation Coefficient. Results: Greater peak power in the back squat was associated with a greater reduction in peak knee absorption power (r = -0,905, p = 0,005) and less vertical stiffness during jumping was associated with longer step lengths with the advanced footwear technology (AFT) shoes (r = -0,738, p = 0,046). No associations were found between vertical stiffness during jumping and contact time, EUR with step length and contact time, peak power in the calf raise and Achilles tendon moment arm with peak ankle propulsive power. Conclusion: Runners with less vertical stiffness in the lower limb during jumping exhibited greater step length increase with AFT shoes. This may be due to the spring-like behavior the shoes possess. However, the larger step length increases the demands on lower limb strength and runners with less power in the lower limb may increase their knee absorption power during ground contact, leading to potentially less efficient running mechanics. Those with greater power in the lower limb may, on the other hand, run more efficiently by decreasing their knee absorption power leading to less muscular effort. / Bakgrund: De senaste årens förbättringar inom långdistanslöpning har föreslagits bero på de teknologiska framstegen som gjorts inom löparskokonstruktion. Det verkar emellertid finnas en skillnad i den prestationshöjande effekt som dessa skor framkallar, där vissa löpare upplever en försämring medan andra förbättras avsevärt. Orsaken till detta är fortsatt okänt men kan ha att göra med skillnader i antropometriska och neuromuskulära egenskaper mellan löpare. Syfte: Syftet med denna uppsats var att undersöka sambandet mellan individuella antropometriska och neuromuskulära egenskaper hos löpare med förändringar i löpmekanik som dessa nya generationens skor framkallar.Metod: Åtta manliga långdistanslöpare utförde fyra olika testprotokoll under ett enda besök. Dessa bestod av ett antropometriskt protokoll där längd, vikt, benlängd och momentarmslängd av Akillessenan mättes; ett hopprotokoll där vertikal styvhet och EUR registrerades med hjälp av en kraftplatta; ett löpprotokoll där kontakttid, steglängd, fotledskraft och knäledskraft mättes med hjälp av kraftplattor och ett rörelseanalyssystem med 12 kameror; och slutligen ett kraft-hastighetsprotokoll där varje deltagare utförde tåhävningar och knäböj med stigande belastning i en smith-maskin medan skivstångshastighet samtidigt registrerades. Den insamlade data analyserades därefter med Wilcoxon Signed-Rank Test och Spearman’s Rank Correlation Coefficient. Resultat: Högre peak power i benböj var associerat med en större minskning av maximal knäabsorptions power (r = -0,905, p = 0,005) och mindre vertikal styvhet under vertikalhopp var associerad med längre steglängd med AFT-skorna (r = -0,738, p = 0,046). Inget samband hittades mellan vertikal styvhet under vertikalhopp och kontakttid, EUR med steglängd och kontakttid, maximal power i tåhävningar och hälsenans momentarm med maximal propulsionspower i fotleden. Konklusion: Löpare med mindre vertikal styvhet i de nedre extremiteten under vertikalhopp uppvisade större steglängdsökning med AFT-skor. Detta kan bero på det fjäderliknande beteende skorna har. Den längre steglängden ökar dock kraven på styrkan i den nedre extremiteten och löpare med mindre kraft, har potentiell ökad knäabsorptions power under markkontakt vilket kan resultera i en mindre effektiv löpmekanik. De med bättre kraftutveckling i de nedre extremiteten kan däremot potentiellt springa mer effektivt med dessa nya generationens skor genom en minskning i knäabsorptions power vilket i sin tur leder till mindre muskulär ansträngning.

Background Knee osteoarthritis is a degenerative joint disease characterized by damaged cartilage, tendons, ligaments, synovium, and bone. Knee osteoarthritis causes joint pain, reduced joint function, and decreased quality of life and is the leading cause of chronic disability in older adults. Two of the major risk factors for knee osteoarthritis are increasing age and obesity. To decrease the occurrence of knee osteoarthritis in our aging population, it is important that we identify exercises that are safe for people with or at risk of knee osteoarthritis. Purpose The main purpose of this thesis was to compare the acute response of knee cartilage composition to two common aerobic activities, running and bicycling, of equal total load. To address the primary purpose, we first sought to determine the reliability and validity of measuring loading repetition during running (steps) and bicycling (pedal-revolutions) using accelerometry. Methods 1) Twenty-two healthy adults completed running and bicycling activity bouts (five-minutes) while wearing six accelerometers: two at each the waist, thigh and shank. Accelerometer and video data were collected during each activity. 2) Fifteen healthy men completed running and bicycling activities of equal cumulative load that were preceded and followed by a series of magnetic resonance images. Results 1) Excellent reliability (ICC≥.99; SEM≤1.0) and validity (Pearson≥.99) were found for step and pedal revolution measurements taken by an accelerometer placed at the shank. 2) Bicycling did not cause significant changes in cartilage composition (p=0.274); however, running did cause a change in cartilage composition (p=0.002). Conclusion Findings from this thesis suggest that to acquire reliable and valid step and pedal revolution measurement, accelerometers should be placed on the shank. Furthermore, bicycling causes no statistical changes in knee cartilage, while running does. Bicycling may therefore be used to combat obesity and maintain cardiovascular health in individuals with compromised joint health. / Thesis / Master of Science (MSc) / Knee osteoarthritis is a degenerative joint disease that affects all knee tissues, particularly articular cartilage. This “wear and tear” condition reduces mobility and creates pain, collectively decreasing quality of life. Two important risk factors for knee osteoarthritis are age and obesity. While we cannot stop aging, exercise can have a positive impact on weight, particularly among adults with knee osteoarthritis. This thesis provides foundational information on how running and bicycling affects knee cartilage. First, we identified a useful method of measuring steps during running and pedal revolutions during bicycling. Second, we compared the effect of running and bicycling of equal cumulative load on knee cartilage, using MRI. The running activity was 1/3 the length of the bicycling activity but despite shorter exposure, running caused changes in cartilage shape and composition, while bicycling did not. These findings suggest that bicycling is a suitable aerobic activity that reduces loading at the knee.

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The popularity of running barefoot or in minimalist shoes has notably increased in the last decade due to claims of injury prevention, enhanced running efficiency, and improved performance when compared to running in shoes (shod). A systematic review of the literature was performed using the Downs and Black checklist to assess the methodological quality of studies proposing risks or benefits between running barefoot, shod, or in minimalist shoes. The databases Ovid MEDLINE, SPORTDiscus, and CINAHL were searched using keywords or "Booleans" including: "Barefoot", "Running" and "Minimalist," exclusively. All included articles were obtained from peer reviewed journals in the English language with a link to full text and no limit for year of publication. The final selection was made based on inclusion of at least one of the following outcome variables: pain, injury rate, running economy, joint forces, running velocity, electromyography, muscle performance, or edema. Significant results were gathered from identified articles and compared using "Levels of Evidence" by Furlan et al. Twenty-three publications were identified and rated for quality assessment in September 2013. Out of 27 possible points on the Downs and Black checklist, all articles scored between 13 and 19 points with a mean of 17.4. Evidence from the articles ranged from very limited to moderate. Moderate evidence suggested overall less maximum vertical ground reaction forces, less extension moment and power absorption at the knee, less foot and ankle dorsiflexion at ground contact, less ground contact time, shorter stride length, increased stride frequency (cadence), as well as increased knee flexion at ground contact in barefoot running compared to shod. The low scores from the quality assessment using the Downs and Black checklist indicates that improved methodological quality is necessary to provide strong evidence comparing the risks and benefits of running barefoot, shod, and in minimalist shoes. The literature between shod, minimalist, and barefoot running is inconclusive. There is limited evidence showing differences in kinematics, kinetics, electromyography, and economy results in minimalist shoes. Thus, an alternative and suitable method to effectively replicate barefoot running has not yet been determined.