In legged terrestrial locomotion, the duration of stance phase, i.e., when limbs are in contact with the substrate, is positively correlated with limb length, and negatively correlated with the metabolic cost of transport. These relationships are well documented at the interspecific level, across a broad range of body sizes and travel speeds. However, such relationships are harder to evaluate within species (i.e., where natural selection operates), largely for practical reasons, including low population variance in limb length, and the presence of confounding factors such as body mass, or training. Here, we compared spatiotemporal kinematics of gait in Longshanks, a long-legged mouse line created through artificial selection, and in random-bred, mass-matched Control mice raised under identical conditions. We used a gait treadmill to test the hypothesis that Longshanks have longer stance phases and stride lengths, and decreased stride frequencies in both fore- and hind limbs, compared with Controls. Our results indicate that gait differs significantly between the two groups. Specifically, and as hypothesized, stance duration and stride length are 8–10% greater in Longshanks, while stride frequency is 8% lower than in Controls. However, there was no difference in the touch-down timing and sequence of the paws between the two lines. Taken together, these data suggest that, for a given speed, Longshanks mice take significantly fewer, longer steps to cover the same distance or running time compared to Controls, with important implications for other measures of variation among individuals in whole-organism performance, such as the metabolic cost of transport.

abstract: Multiple Sclerosis, an autoimmune disease, is one of the most common neurological disorder in which demyelinating of the axon occurs. The main symptoms of MS disease are fatigue, vision problems, stability issue, balance problems. Unfortunately, currently available treatments for this disease do not always guarantee the improvement of the condition of the MS patient and there has not been an accurate mechanism to measure the effectiveness of the treatment due to inter-patient heterogeneity. The factors that count for varying the performance of MS patients include environmental setting, weather, psychological status, dressing style and more. Also, patients may react differently while examined at specially arranged setting and this may not be the same while he/she is at home. Hence, it becomes a major problem for MS patients that how effectively a treatment slows down the progress of the disease and gives a relief for the patient. This thesis is trying to build a reliable system to estimate how good a treatment is for MS patients. Here I study the kinematic variables such as velocity of walking, stride length, variability and so on to find and compare the variations of the patient after a treatment given by the doctor, and trace these parameters for some patients after the treatment effect subdued. / Dissertation/Thesis / M.S. Bioengineering 2012

Title: Evaluation of post-activation potentiation effect on performance indicators of sprint following crouch start Objectives: The main objective of this thesis is to evaluate the influence of post- activation potentiation phenomenon on sprinter step performance indicators following crouch start by using Optojump system. Secondary objectives are firstly - to complile systematic up-to-date review based on recently published evidence, and secondly - to compare acquired results with current trends described in this review. Methods: Fifteen (n = 15) moderate to well trained male athletes completed the experimental procol of controlled sprints (20 m), activation of post-activation potentiation / post-activation performance enhancement elicited by series of squats (3 series, 5 repetition, load of 75 % of 1RM, resting interval 2 mins). Following the activation, all participants completed 1x20 m of sprinting performance from crouch start at 5 min, 10 min, 20 min and 40 min. All measurments were made by using the Optojump system. Acquired measurments were further analyzed and statistically evaluated. Results: Evaluation of acquired data did not result in significant positive effect of activation protocol on measured variables. Furthemore, series of squats were associated with decreased peak velocity and...

A wearable system that can be used in different settings to collect gait parameters on subjects with a mild traumatic brain injury (mTBI) would allow clinicians to collect needed data of subjects outside of the laboratory setting. Mild traumatic brain injuries stem from a number of causes such as illnesses, strokes, accidents or battlefield traumas. These injuries can cause issues with everyday tasks, such as gait, and are linked with vestibular dysfunction [1]. Different wearable sensor systems were analyzed prior to starting this study along with relevant gait parameters associated with mild traumatic brain injury. To monitor gait parameters relevant to mild traumatic brain injury (cadence, torso rate of rotation, head rate of rotation and stride length) a wearable sensor system was selected (APDM Opal Movement Monitor [13]) and compared against the gold standard optical tracking system (Vicon) [2]. A group of ten, 20-27 year old, healthy subjects were used to validate the APDM Movement Monitor system using the Pearson's R correlation value [35]. Subjects were asked to wear the APDM movement monitors in conjunction with the reflective markers of the Vicon system while performing three sessions of gait trials: a normal gait speed, a fast gait speed and a slow gait speed. Using the Pearson's R correlation values, cadence, torso rate of rotation, and head rate of rotation were found to be highly correlated between both systems. The Pearson's R correlations for cadence, torso rate of rotation, head rate of rotation and stride length were 0.967, 0.907, 0.942, and 0.861, respectively. These correlation values suggest the gait parameters relevant to mild traumatic brain injury are highly correlated between both the APDM Movement Monitor system and the Vicon system, and APDM's wearable sensor system was lightweight, portable and less costly than the Vicon system.

The purpose of this study was to determine the acute effects of heavy resistance exercise on agility performance in court-sport athletes. Five men (age: 20.6 ± 1.9 years; body mass: 79.36 ± 11.74 kg; body height: 1.93 ± 0.09 m) and five women (age 21.2 ± 2.7 years; body mass: 65.8 ± 10.18 kg; body height 1.77 ± 0.08 m) volunteered to participate in the present study. All subjects were NCAA Division II athletes who currently participated in tennis or basketball and all had previous resistance training experience of at least one year. In a counterbalanced design, agility performance during a 10 m shuttle test was assessed following either a dynamic warm-up (DW) or heavy resistance warm-up (HRW) protocol. The HRW protocol consisted of three sets of squats at 50, 60, and 90% of 1-RM. Agility performance was captured using an eight camera motion analysis system and the mechanical variables of stride length, stride frequency, stance time, flight time, average ground reaction force, as well as agility time were recorded. No significant differences were reported for the HRW and DW protocols for any of the mechanical variables (p>0.05), although there was a trend towards the HRW protocol producing faster agility times compared to the control protocol (p = 0.074). Based on the trend towards a significant effect, as well as individual results it is possible that HRW protocols could be used as an acute method to improve agility performance in some court-sport athletes.

The purpose of this study was to determine the acute effects of heavy resistance exercise on agility performance in court-sport athletes. Five men (age: 20.6 ± 1.9 years; body mass: 79.36 ± 11.74 kg; body height: 1.93 ± 0.09 m) and five women (age 21.2 ± 2.7 years; body mass: 65.8 ± 10.18 kg; body height 1.77 ± 0.08 m) volunteered to participate in the present study. All subjects were NCAA Division II athletes who currently participated in tennis or basketball and all had previous resistance training experience of at least one year. In a counterbalanced design, agility performance during a 10 m shuttle test was assessed following either a dynamic warm-up (DW) or heavy resistance warm-up (HRW) protocol. The HRW protocol consisted of three sets of squats at 50, 60, and 90% of 1-RM. Agility performance was captured using an eight camera motion analysis system and the mechanical variables of stride length, stride frequency, stance time, flight time, average ground reaction force, as well as agility time were recorded. No significant differences were reported for the HRW and DW protocols for any of the mechanical variables (p>0.05), although there was a trend towards the HRW protocol producing faster agility times compared to the control protocol (p = 0.074). Based on the trend towards a significant effect, as well as individual results it is possible that HRW protocols could be used as an acute method to improve agility performance in some court-sport athletes.

In the sport of track and field, sprinting and distance running represent two major categories of athletes. Sprinting is associated with power and speed, whereas distance running focuses on the economy of movement. With distance running there are elements of sprint technique that overlap. With distance events, there comes a time near the end of the race where economy gives way to speed. If the distance runners knew how to alter their technique in a way to become more sprint-like, this process could possibly be more successful. PURPOSE: This study compared the differences in technique between sprinters and distance runners while running at equal and maximal speeds. METHODS: Subjects for the study consisted of 10 Division I collegiate distance runners, 10 Division I collegiate sprinters, and 10 healthy non-runners. The subjects performed two tests, with each consisting of a 60 meter run completed on the track. Test 1 was run at a pace of 5.81 m/s (4:37 min/mile), while Test 2 was completed at maximal speed. Video footage of each trial was collected at 180 Hz, monitoring hip, knee, thigh, and shank positions, as well as stride length, and contact time. RESULTS: Significant differences (p < .05) between the sprint and distance groups at maximal speed were found in the following areas: speed, minimum hip angle, knee extension at toe-off, stride length, contact time, and the position of the recovery knee at touchdown. Sprinters and distance runners exhibited a significantly lower minimum knee angle than those in the control group. Significant differences between the sprint and control group existed at the minimum hip angle, speed, stride length, contact time, and the position of the recovery knee at touchdown. Regarding the paced trial, the sprinters and distance runners showed significant difference concerning the minimum hip angle, center of mass at touchdown, and recovery knee at touchdown. Sprinters differed significantly from the control group in contact time, the center of mass at touchdown and the position of the recovery knee at touchdown. CONCLUSION: As distance runners attempt to sprint, the desired adaptations do not necessarily occur. The development of economical distance form is a fairly natural process that occurs with the miles of training. Sprinting, however, is a separate, learned technique that often requires specific feedback. When attempting maximal speed, distance runners may benefit by focusing on one characteristic of technique. If knee extension at toe-off could be trained to become more sprint-like, the other characteristics unique to sprinters may follow.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-08-23T11:00:21Z No. of bitstreams: 1 giseleoliveirasantospires.pdf: 612429 bytes, checksum: 645905e744fd2a58ac4b8da2c3ffe2b2 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-08-28T12:36:45Z (GMT) No. of bitstreams: 1 giseleoliveirasantospires.pdf: 612429 bytes, checksum: 645905e744fd2a58ac4b8da2c3ffe2b2 (MD5) / Made available in DSpace on 2018-08-28T12:36:45Z (GMT). No. of bitstreams: 1 giseleoliveirasantospires.pdf: 612429 bytes, checksum: 645905e744fd2a58ac4b8da2c3ffe2b2 (MD5) Previous issue date: 2018-07-20 / Introdução - A esteira é um instrumento apropriado para fornecer uma tarefa de desempenho padronizado e confiável. Embora por tempos, as esteiras tenham sido usadas, principalmente, para pesquisas, atualmente são muito comuns em academias de ginástica e vêm, ao longo do tempo, ganhando popularidade no treinamento de resistência. A distância percorrida por cada passo durante a caminhada ou corrida é chamada amplitude de passos e o número de passos dados em um determinado período é a frequência. Desse modo, a velocidade é determinada pelo produto da frequência pela amplitude de passos. A cinemática é uma área da biomecânica que permite o cálculo da posição, do deslocamento, da velocidade e da aceleração do corpo ou de seus segmentos, tendo como principal foco a descrição de como um corpo se move. Os parâmetros cinemáticos para análise da velocidade da corrida incluem o comprimento e a frequência do passo e da passada, bem como todas as variáveis espaço-temporais derivadas dessas. Não são recentes as investigações que pretendem tecer um paralelo entre deslocamento em piso fixo e esteira, porém seus resultados são inconsistentes. Esta inconsistência parece estar relacionada com as diferenças metodológicas, na aptidão física dos voluntários, velocidades estabelecidas nos protocolos de teste e com os métodos para determinar essas velocidades de corrida em cada estudo. Objetivo – Analisar se as variáveis frequência e amplitude de passos comportam-se de maneira pariforme ao se comparar a corrida na pista com a corrida na esteira; havendo diferenças, verificar se essas seriam imutáveis ou se o indivíduo é capaz de escolher com que combinação de frequência e amplitude quer correr e, ainda, verificar se essas seriam aleatórias ou determinadas por alguma das variáveis que caracterizaram a amostra. Métodos - 22 corredores participaram do estudo, VO2max 59,8 ± 5,53; VMA 17,4 ± 1,59; idade 33,7 ± 10,84; estatura 1,76 ± 0,07; massa corporal 69,18 ± 9,31. Foram realizados 3 testes, teste máximo, na pista e na esteira, nessa ordem para todos os voluntários. Resultados - Para os percentuais 100 e 120 da VMA foram encontrados valores reduzidos de amplitude e aumentados de frequência na esteira em relação à pista. Ainda, podemos predizer que corredores bem treinados conseguem realizar corridas com menores diferenças entre esteira e pista, sobretudo a 120% da VMA. Conclusão - As variáveis frequência e amplitude de passos comportam-se de maneira pariforme ao se comparar a corrida na pista com a esteira nos percentuais 60 e 80 da VMA, para 100 e 120% a amplitude de passos é maior e a frequência menor na esteira em comparação ao solo para uma mesma velocidade. Essas diferenças não são imutáveis, os corredores são capazes de escolher com que combinação de amplitude e frequência de passos desejam correr. Ainda, as diferençaspodem ser determinadas, principalmente nos 120% da VMA, pelo nível de condicionamento dos corredores. / Introduction - A treadmill is an appropriate instrument to provide a standardized and reliable performance task. Although it had been used mostly for research, currently it has been widely used at gyms and has gained popularity at endurance training. The distance between strides during the walk or the run is called stride length, and the number of strides during a certain period of time is the frequency. This way, the speed is determined by stride length times stride frequency. The kinematics is a biomechanics subject that allows to measure the position, displacement, speed, and acceleration of the body or its segments. The kinematic major focus is to describe how the body moves. The kinematic parameters for speed analysis include stride and pace frequency and length as well as all space-time variables and all their variations. The researches which tried to draw a comparison between track and treadmill run are inconsistent nor even recent. This inconsistency seems to be related to the differences among methodology, endurance capacity of volunteers, speed at test protocols, and methods to estimate this speed in each study. Objective - To analyse if stride length and stride frequency behave similarly by comparing a track and a treadmill run. And if there are differences, the purpose is to check if they are unchangeable or if the subject is able to choose which frequency and amplitude they want to run and also to verify if they are randomized or pre-determinate by some peculiarity of the sample. Methods - 22 runners participated of this study with VO2max 59,8 ± 5,53, MAS 17,4 ± 1,59, age 33,7 ± 10,84, body mass 69,18 ± 9,31. Three tests were conducted in this order: maximal test, treadmill and track tests for all volunteers. Results - For a 100% and 120% MAS a decreased value of stride length and an increased value of stride frequency were found at treadmill compared to track. We believe runners prefer to run this way, because they run differently when they receive verbal stimulus to change the technique. We can also predict that well-trained runners manage to run at lower differences between treadmill and track, specially at 120 % of MAS. Conclusion - For stride length and stride frequency, no difference was found at 60% and 80% of MAS, but at 100% and 120%, stride length is higher and stride frequency lower at treadmill compared to track at same speed. These differences are not unchangeable; runners are capable of choosing which combination of stride length and stride frequency they prefer to run. Besides, the differences may be determined, mostly at 120% of MAS by the fitness level of the runners.

The purpose of this study was to examine the differences in technique between sprinters and baseball players while running at maximal speeds. 20 male NCAA Division I athletes participated; ten members of the track and field team specializing in the 100 m or 200 m sprint or the 100 m hurdles and ten members of the baseball team. Each subject performed a maximal effort 80 m sprint while their sprint times were recorded every 10 m starting at the 20 m mark. Each subject was filmed at they ran through a set10 m marking that included where they reached their top speed allowing the camera to capture at least one complete stride. By using the Peak Motus System, each subject's minimum knee flexion, minimum hip angle, knee extension at toe off, contact time, stride length, center of mass at touchdown and shank angle were measured. ANOVA with repeated measures found that sprinters and baseball players display significant differences in their sprinting technique in all variables except shank angle with the sprinters displaying a shorter 10 m split time. It was concluded that proper sprint training during baseball practice could prove to be beneficial to baseball players, however, further research would need to be conducted to support this claim.

Previous studies have used accelerometers with various operating ranges (ORs) when measuring biomechanical parameters. However, it is still unclear whether ORs influence the accuracy of running parameters, and whether the different stiffnesses of footwear midsoles influence this accuracy. The purpose of the present study was to systematically investigate the influence of OR on the accuracy of stride length, running velocity, and on peak tibial acceleration. Twenty-one recreational heel strike runners ran on a 15-m indoor track at self-selected running speeds in three footwear conditions (low to high midsole stiffness). Runners were equipped with an inertial measurement unit (IMU) affixed to the heel cup of the right shoe and with a uniaxial accelerometer at the right tibia. Accelerometers (at the tibia and included in the IMU) with a high OR of ±70 g were used as the reference and the data were cut at ±32, ±16, and at ±8 g in post-processing, before calculating parameters. The results show that the OR influenced the outcomes of all investigated parameters, which were not influenced by tested footwear conditions. The lower ORs were associated with an underestimation error for all biomechanical parameters, which increased noticeably with a decreasing OR. It can be concluded that accelerometers with a minimum OR of ±32 g should be used to avoid inaccurate measurements.