Judging time-to-contact with a target is an important criterion for avoiding harm in everyday walking and running tasks, and maximizing performance in high-velocity sporting tasks. The information-based regulation of step length and duration during target-directed locomotion was examined in relation to gait mode, approach velocity, target task, expertise, and sporting performance during a series of four experiments. The first three experiments examined novice performers (Each n=12, 6 males, 6 females), whilst the last experiment examined expert gymnasts (n=5). Two reference strips with alternating 50cm black and white intervals were placed on either side of the approach strip for all of the experiments. One 50Hz-panning video camera filmed the approach from an elevated position. In Experiment 4, two stationary 250Hz cameras filmed the post-flight performance of the gymnastic vaults and, in addition, two qualified judges provided a performance score for each vaulting trial. The panning video footage in each experiment was digitized to deduce the gait characteristics. In Experiment 4, the high-speed video footage was analyzed three-dimensionally to obtain the performance measures such as post-flight height. The utilization of visual stimulus in target-directed locomotion is affected by the observer's state of motion as characterized by the mode of locomotion and also often the speed of locomotion. In addition, experience plays an important role in the capacity of the observer to utilize visual stimulus to control the muscular action of locomotion when either maintaining or adjusting the step mechanics. The characteristics of the terrain and the target also affect the observer's movement. Visual regulation of step length decreases at higher approach speeds in novice performers, where as expert performers are capable of increasing visual regulation at higher approach speeds. Conservatism in final foot placement by female participants accounts for the observed increase in distance from the critical boundary of the obstacle relative to toe placement. Behavioural effects of gender thus affect the control of final foot placement in obstacle-directed locomotion. The visual control of braking in target-directed locomotion is described by a tau-dot of-0.54. When tau-dot is below -0.54 a hard collision with the obstacle will occur, however, when tau-dot is above -0.54, a soft collision with the target will occur. It is suggested that the tau-dot margin defining the control of braking reveals the braking capacity of the system. In the target-directed locomotion examined a tau-dot greater than -0.70 would possibly exceed the braking capacity of the system, thus, leading to injury if performed. The approach towards the take-off board and vaulting horse in gymnastics is an example of target-directed locomotion in sport. Increased visual regulation of the timing and length of each step is a requirement for a fast running approach, a fundamental building block for the execution of complex vaults in gymnastics. The successful performance of complex vaults in gymnastics leads towards a higher judge's score. Future research suggestions include an investigation of visual regulation of step length in curved target-directed locomotion.

This study wished to compare the same physiological responses of elite athletes to a typical intermediate term anaerobic capacity track running session with those of standing cycling of similar intensity and duration. Twelve well trained/elite male distance runners completed maximal running, standing cycling and strength testing sessions; and Intermediate Term Anaerobic Capacity Sessions (ITACS) in running and standing cycling; each comprising eight efforts of approximately 30 seconds duration at 90% maximal effort in each mode of activity, separated by 2 minutes rest. The experimental sessions took place from the end of November 1996 to the beginning of March 1997. The subjects were required to attend three maximal experimental sessions, which were performed on separate days and used for baseline data collection. On completing these they participated in both running and standing cycling ITACS, performed on separate days with at least 48 hours between each test protocol. There was complete randomisation of all test protocols. Descriptive statistics were determined for all the variables. Independent t-testing was used to determine if similar temperature and humidity readings were obtained during the maximal testing for each mode of activity. Paired t-testing was used to compare the differences in warmup heart rates between the maximal and ITACS, the differences in peak lactates obtained after each type of ITACS, draw comparisons between heart rate (HR) changes over time during the ITACS and determine if a difference existed between workloads for the two modes of activity. It was also used to draw a comparison between the peak BLa values and ascertain if pre-test creatine kinase (CK) levels were the same for each mode of activity. A repeated measures one way ANOVA was used to determine if workload reduced over time for each type of ITACS. A three way ANOVA with repeated measures on one factor (repetition) was performed on HR response. It was used to determine if there was a difference between the workload/recovery HR response; if workload/recovery HR values increased over the duration of each ITACS; and if the workload/recovery HR response over time was mode specific. A two way ANOVA with repeated measures on one factor (repetition) was performed on blood lactate (BLa) response. It was used to determine if there was a significant interaction between the mode of activity and time, if BLa increased over the duration of each ITACS and if there was an effect of mode on its own on the BLa response. A two way repeated measures ANOVA was used to ascertain whether there was a difference in CK levels between the two modes of activity, with Tukey's multiple comparison tests used in post hoc analyses to show the amount of difference. A linear regression analysis was performed to determine if BLa response was similar across the duration of each type of ITACS. The effects of temperature (22.3 ± 1.2 vs 21.1 ± 0.3 °C, run vs cycle, t = -0.94, n = 12, p = 0.36)) and humidity (57 ±4.2 vs 52 ± 1.7%, run versus cycle, t = -1.04, n = 12, p = 0.31) did not influence any of the results obtained during the ITACS. Nor did differing warmup intensities (as indicated by heart rate - HR) during the maximal (160 ± 5.7 vs 158 ± 3.1 beats per minute (bpm), run vs cycle, t = - 0.45, n = 9, p = 0.66) and ITACS (160 ± 3.6 vs 152 ± 3.1 bpm, run vs cycle, t = -2.81, n = 9, p = 0.02). An equal test preparation was confirmed by the warmup blood lactate (BLa) levels, which were not significantly different between the exercise modes for both the maximal (11.0 ±0.6 vs 11.8 ± 1.0 mmol-l1, run vs cycle, t = 2.26, ii n = 10, p =0.23) and ITACS (4.2 ± 0.7 vs 4.2 ± 0.6 mmol-1 ', run vs cycle, t = 0.27, n = 10, p = 0.796). A significantly higher workload was achieved during the running ITACS as compared to the standing cycling ITACS (105 ± 1.1 vs 89 ±2.9 %, run vs cycle, t = 10.45, n = 12, p<0.0005). The increase in workload/recovery HR response and their changes as each type of ITACS progressed was not mode specific [F(l,40) = 0.94, p > 0.05]. Those subjects who possessed high BLa concentrations performed less work on the cycle ergometer. There was a strong negative relationship for average workloads and BLa accumulation for the standing cycling exercise (Spearmans rho = -0.799, n = 11, p<0.005) suggesting that BLa accumulation was a limiting factor in work production. The increase in BLa levels was not mode specific F(l,20) = 1.36, p > 0.05]. The BLa response was comparatively similar because the rate of increase in BLa accumulation and peak BLa values (19.7 vs 16.9 mmol-l'1, cycle vs run, t = 2.1, n = 11, p = 0.06) were not significantly different between the modes of activity. Mode in conjunction with time affected standing cycling BLa response to a greater extent than running BLa levels [F(4.80) =3.929, p <. 0.05]. Standing cycling BLa concentrations were significantly negatively correlated with knee extension peak torque (Spearmans rho = - 0.771, n = 11, p < 0.01) and total work (Spearmans rho = - 0.802, n = 11, p < 0.01) measurements. In running they were negatively correlated with knee flexion total work measurements (Spearman rho = - 0.685, n = 11, p < 0.05) These findings suggest that BLa accumulation occurs from different muscle fibre recruitment patterns. Less work was performed in isokinetic knee extension following standing cycling as compared to running (2234 ± 68.4 vs 2462 ± 78.9 Nm, t = 2.23, n = 11, p < 0.05) suggesting that standing cycling is more fatiguing on the quadriceps than running. There was no difference in the knee flexion testing (1799 ± 89.6 vs 1785 ± 69.2, cycle vs run, t = 2.23, n = 11, p = 0.96). There was a significant difference in mean creatine kinase (CK) activity between the two modes 24 hours after completing the ITACS (450 ± 73.2 vs 320 ± 46.5 I/U, running vs cycle, F = 6.44, df = 1,17, p < 0.01). There was a significantly greater increase in CK activity and therefore muscle damage, following the running (mean increase of 190 I/U) as compared to the standing cycling session (mean increase of 44.0 I/U). In terms of reducing the risk of injury, achieving a similar cardiovascular response and achieving comparable BLa accumulation (even though mechanism/s of accumulation may be different) standing cycling appears to be is a satisfactory substitute for running during an ITACS. The results of this research strengthen the concept of utilising a simulated mode of activity as a substitute for the primary activity in order to maximise transfer effects, providing there is a careful balance between the specific training and the near specific training. The differing physiological responses between the exercise modes (ie- different muscle fibre recruitment patterns, different workload capacity, different CK measures) suggest that standing cycling cannot act as a total/comprehensive replacement for running. A training study is warranted to further investigate the findings of this research.

Past research on the acceleration phase in sprint running has concentrated on the kinematics of sprint blocks set-up and the initial steps after exiting the sprint blocks. In contrast, there has been limited research on the ground reaction forces (GRF) generated during the initial post-block foot contacts. These initial foot contacts in sprinting are important for optimising performance in the initial acceleration phase of sprinting. However, little is known about the GRF elite sprinters generate during the initial foot contacts and how these GRF characteristics relate to performance. It is the anterior-posterior (A-P) GRF that are of most importance as they indicate the sprinter’s motion from the start to the finish line. This thesis investigates the A-P GRF of the first two foot contacts of the sprint start after leaving the blocks. The participants included seventeen male and six female sprinters with a mean age of 22.6 (SD 4.4 years). Seventeen of the sprinters had competed at international/national level competitions and six at recreational/amateur level competitions. The athletes were classified as senior male elite (SME), senior female elite (SFE), junior male elite (JME) and senior male recreational (SMR). The sprinters were instructed to perform block starts at maximal effort to produce the fastest time over 5 metres on a 30 metre indoor laboratory track. Timing gates were used to record 5 metre times and two strain gauge force plates were placed in series to collect GRF data from the first two foot contacts after leaving the starting blocks. From the GRF data, braking time, maximum A-P braking force, A-P braking impulse, propulsive time, maximum A-P propulsive force, A-P propulsive impulse and A-P contact impulse were determined for each trial. The A-P propulsive phase constituted greater than 90% of the total contact time, had approximately twice the magnitude of the maximum force of the braking phase and accounted for more than 95% of the total contact impulse across the four groups of sprinters. The SME group produced a significantly larger A-P propulsive impulse on the first and second steps compared to the SFE (p less than 0.05 and p less than 0.05 respectively), JME (not significant and p less than 0.05 respectively) and SMR (p less than 0.05 and p less than 0.05 respectively) groups. The SME group’s maximum A-P propulsive force was significantly larger on the first and second steps than the SFE (p less than 0.05 and p less than 0.05 respectively), JME (p less than 0.05 and p less than 0.05 respectively) and SMR (p less than 0.05 and p less than 0.05 respectively) groups. The SME group’s propulsive time on the first and second steps was not significantly different compared to the SFE (both not significant) but was significantly shorter compared to the JME (p less than 0.05 and p less than 0.05 respectively) and SMR (p less than 0.05 and p less than 0.05 respectively) groups. The maximum A-P propulsive force correlated strongly with 5 metre time for the first step (rs = -0.670, p less than 0.01), second step (rs = -0.621, p less than 0.01) and the addition of the first and second steps (rs = -0.678, p less than 0.01) across all the sprinters. Whereas, the A-P propulsive impulse correlated strongly with 5 metre time for the first step (rs = -0.525, p less than 0.01), second step (rs = -0.592, p less than 0.01) and the addition of the first and second steps (rs = -0.584, p less than 0.01). Three A-P GRF patterns were observed during the first and second foot contacts of the sprinters examined in this study. A braking-propulsive (B-P) pattern was the most frequently observed followed by a propulsive-braking-propulsive (P-B-P) and a no braking (NB) pattern 82.7%, 15.4% and 1.9% respectively. The P-B-P and NB patterns, which have not been described previously, appeared most frequently in the least experienced sprinters. In the past, some sprinters and their coaches have tried to minimise the braking phase and maximise the propulsive phase of the first two foot contacts after exiting the blocks during sprinting. This study suggests that increasing the maximum propulsive force is the best way to increase performance over the first 5 metres of the acceleration phase. The research also suggests that there will be little benefit gained from trying to increase performance by focusing on the braking phase during these first two steps after exiting the blocks. As such, sprinters and coaches should focus their attention primarily on producing a large A-P propulsive force during the first two steps of a sprint.

Tibial stress fractures are common in runners. However, it is unclear what factors are associated with tibial stress fractures. This study aimed to investigate 1) magnitudes of bone contact forces occurring while running 2) whether or not repeated application of running loads is sufficient to explain tibial stress fractures and 3) whether or not muscle fatigue alters the potential of tibial stress fractures. Tibial stress fractures were predicted through an estimation of the minimum number of cycles to failure (Nfail) using an integrated experimental and mathematical modeling approach. Short running trials within a speed range of 3.5-4 m/s of ten male runners were evaluated with a coupled force plate and 3 dimensional motion analysis system. The collected data were used to estimate joint reaction forces (JRF) and joint moments. Using these JRF and muscle forces predicted from optimization, 2-D bone contact forces at the distal end of the tibia were determined. Next, tibial stresses were estimated by applying these bone contact forces to a tibial model, which were then used to predict the Nfail. All procedures were repeated after plantarflexors fatigued from prolonged running. This study found that peaks of compressive and posterior shear forces occurred during mid stance, and these peaks equaled 8.91 ± 1.14 BW and -0.53 ± 0.16 BW, respectively. These bone contact forces led to a backward bending of the tibia during most of the stance phase and resulted in the maximum stresses of - 43.4 ± 10.3 MPa on the posterior face of the tibia. These maximum stresses predicted the group mean of Nfail as being 5.28*10⁶ cycles. However, 2.5% to 56% of population of runners have a chance of getting tibial stress fractures within 1 million cycles of a repeated foot impact. Within the context of muscle force and stress estimation procedures used in this study, Nfail appeared to increase after fatigue, not decrease as we hypothesized. / Graduation date: 2005

Carbody tilting is today a mature and inexpensive technology that allows higher train speeds in horizontal curves, thus shortening travel time. This doctoral thesis considers several subjects important for improving the competitiveness of tilting trains compared to non-tilting ones. A technology review is provided as an introduction to tilting trains and the thesis then focuses on enhancing the benefits and strategies for less motion sickness. A tilting train may run about 15% faster in curves than a non-tilting one but the corresponding simulated running time benefit on two Swedish lines is about 10%. The main reason for the difference is that speeds are set on other grounds than cant deficiency at straight track, stations, bridges, etc. The possibility to further enhance tilting trains’ running speed is studied under identified speed limitations due to vehicle-track interaction such as crosswind requirements at high speed curving. About 9% running time may be gained on the Stockholm–Gothenburg (457 km) mainline in Sweden if cant deficiency, top speed, and tractive performance are improved compared with existing tilting trains. Non-tilting high-speed trains are not an option on this line due to the large number of 1,000 m curves. Tilting trains run a greater risk of causing motion sickness than non-tilting trains. Roll velocity and vertical acceleration are the two motion components that show the largest increase, but the amplitudes are lower than those used in laboratory tests that caused motion sickness. Scientists have tried to find models that can describe motion sickness based on one or more motion quantities. The vertical acceleration model shows the highest correlation to motion sickness on trains with active tilt. However, vertical acceleration has a strong correlation to several other motions, which precludes vertical acceleration being pointed out as the principal cause of motion sickness in tilting trains. Further enhanced speeds tend to increase carbody motions even more, which may result in a higher risk of motion sickness. However, means to counteract the increased risk of motion sickness are identified in the present work that can be combined for best effect. Improved tilt control can prevent unnecessary fluctuations in motion sickness related quantities perceived by the passengers. The improved tilt control can also manage the new proposed tilt algorithms for less risk of motion sickness, which constitute one of the main achievements in the present study. Local speed restrictions are another means of avoiding increased peak levels of motion sickness when increasing the overall speed. The improved tilt control and the proposed tilt algorithms have proven to be effective in on-track tests involving more than 100 test subjects. The new tilt algorithms gave carbody motions closer to non-tilting trains. Rather unexpectedly, however, the test case with the largest decrease in tilt gave a greater risk of motion sickness than the two test cases with less reduction in tilt. It is likely that even better results can be achieved by further optimization of the tilt algorithms; the non-linear relation between motions and motion sickness is of particular interest for further study. / QC 20110429

Concrete masonry is a multi-component structural system. In the case of reinforced concrete masonry, the system includes the concrete units, the mortar, the reinforcing steel and the grout fill. Placing vertical steel reinforcing bars in the cores of the concrete units enhances the flexural strength of the wall. The vertical steel, when subjected to compression at moderate strain levels, must be confined to improve its resistance to buckling and to improve the effectiveness of the grout around the reinforcing bar. Based on the well established behaviour of reinforced concrete systems, it seems reasonable to presume that the primary means of enhancing ductility is to provide lateral confining steel at closely-spaced intervals to effectively increase the ultimate compressive strain in the grout. It may be assumed that transverse reinforcement in concrete masonry provides lateral confinement to the core so that the axial compressive strength of the grout is enhanced and the ductility improved. <p>The focus of this study was to investigate the effect of vertical reinforcement and lateral confinement on the axial capacity of short partially grouted concrete masonry walls built in running bond. In order to better understand the structural behaviour of both confined and unconfined concrete masonry, it is important to have some knowledge of the load-displacement behaviour, stress-strain behaviour and failure modes of the masonry walls with different configurations of vertical and lateral reinforcement. <p>An experimental study was performed to investigate the behaviour of partially grouted concrete masonry block walls under axial loading. Three types of test specimens of partially grouted concrete block masonry walls were tested: <p>(1) specimens with a grouted core only; <p>(2) specimens with a grouted core and vertical reinforcement (i.e. no confinement); and <p>(3) specimens with a grouted core, vertical reinforcement and spiral confinement in the grouted cores. In total, thirty short wall specimens were tested to failure. <p>The structural behaviour of vertically reinforced, laterally confined walls was compared to vertically reinforced, unconfined walls, as well as to unreinforced, unconfined masonry walls. The test results indicated that vertical reinforcement of the grouted core did not have a significant positive effect on the failure modes and strength of the short masonry walls. Due to problems with adequate compaction, the lateral confinement provided by the spiral reinforcement had a slightly negative effect on the compressive strength of concrete masonry walls built in running bond. Vertical reinforcement and lateral confinement of the grouted core had some positive effect on the ductility. From a comparison of the ductility for all three types of specimens it was found that both the vertical reinforcement and lateral confinement of the core had a beneficial influence on the post-peak ductility. <p>In general, similar crack patterns and failure modes were observed in all three types of specimens. Vertical cracks that progressed through the end faces of the concrete blocks and mortar joints, suggesting that the lateral expansion of the grouted core contributed to tensile splitting stresses in walls. All walls failed in a compression-tension stress state, which featured spalling away of the block shells and vertical tensile splitting on the end faces.

Graduation date: 1991

Over the course of American history, the vice presidency has evolved into a meaningful and influential part of the executive branch, and running mates have become an important part of presidential elections. But scholars, pundits, and political professionals continue to discuss and evaluate vice presidential selection in an outdated framework that now borders on superstition. Now that presidential nominees have sole authority to choose their running mates and the resources to take care in the process, voters demand that they do so. The modern presidential nominee should undertake a serious and methodical research and decision-making process, and should choose a running mate who 1) demonstrates unassailable competence, and 2) bolsters the ticket – not balances it – by extending presidential nominee’s narrative into uncovered territory.

Eight men were studied before and after an endurance training program to assess changes in the lipid metabolism of skeletal muscle. Training consisted of eight weeks of outdoor running with daily mileage increasing from one-half mile at the onset to four miles at the eighth veekof training. In vitro analyses of palmityl-CoA oxidation and the activities of carnitine palmityltransferase (CPT) and succinate dehydrogenase (SDH) were observed in muscle samples obtained by needle biopsy from the gastrocnemius before and after training.The subjects' maximal oxygen uptake increased from 3.47 1/min (± 0.26) to 3.82 1/min (± 0.21) as a result of the training. At the same time, muscle CPT and SDH increased (P <.01) 23% and 36%, respectively. The muscle's capacity to oxidize palmityl-CoA increased from 6.36 nmoles/min/g to 13.32 nmoles/min/g, a significant increase of 116% (P <.01).This investigation supports earlier findings with rats and emphasizes the influence of chronic endurance exercise on lipid metabolism in the skeletal muscle of man.Ball State UniversityMuncie, IN 47306

Concrete masonry is a multi-component structural system. In the case of reinforced concrete masonry, the system includes the concrete units, the mortar, the reinforcing steel and the grout fill. Placing vertical steel reinforcing bars in the cores of the concrete units enhances the flexural strength of the wall. The vertical steel, when subjected to compression at moderate strain levels, must be confined to improve its resistance to buckling and to improve the effectiveness of the grout around the reinforcing bar. Based on the well established behaviour of reinforced concrete systems, it seems reasonable to presume that the primary means of enhancing ductility is to provide lateral confining steel at closely-spaced intervals to effectively increase the ultimate compressive strain in the grout. It may be assumed that transverse reinforcement in concrete masonry provides lateral confinement to the core so that the axial compressive strength of the grout is enhanced and the ductility improved. <p>The focus of this study was to investigate the effect of vertical reinforcement and lateral confinement on the axial capacity of short partially grouted concrete masonry walls built in running bond. In order to better understand the structural behaviour of both confined and unconfined concrete masonry, it is important to have some knowledge of the load-displacement behaviour, stress-strain behaviour and failure modes of the masonry walls with different configurations of vertical and lateral reinforcement. <p>An experimental study was performed to investigate the behaviour of partially grouted concrete masonry block walls under axial loading. Three types of test specimens of partially grouted concrete block masonry walls were tested: <p>(1) specimens with a grouted core only; <p>(2) specimens with a grouted core and vertical reinforcement (i.e. no confinement); and <p>(3) specimens with a grouted core, vertical reinforcement and spiral confinement in the grouted cores. In total, thirty short wall specimens were tested to failure. <p>The structural behaviour of vertically reinforced, laterally confined walls was compared to vertically reinforced, unconfined walls, as well as to unreinforced, unconfined masonry walls. The test results indicated that vertical reinforcement of the grouted core did not have a significant positive effect on the failure modes and strength of the short masonry walls. Due to problems with adequate compaction, the lateral confinement provided by the spiral reinforcement had a slightly negative effect on the compressive strength of concrete masonry walls built in running bond. Vertical reinforcement and lateral confinement of the grouted core had some positive effect on the ductility. From a comparison of the ductility for all three types of specimens it was found that both the vertical reinforcement and lateral confinement of the core had a beneficial influence on the post-peak ductility. <p>In general, similar crack patterns and failure modes were observed in all three types of specimens. Vertical cracks that progressed through the end faces of the concrete blocks and mortar joints, suggesting that the lateral expansion of the grouted core contributed to tensile splitting stresses in walls. All walls failed in a compression-tension stress state, which featured spalling away of the block shells and vertical tensile splitting on the end faces.