Bakgrund: Löpning är en populär motionsform i Sverige idag, dock är det vanligt med överbelastningsskador bland löpare och nästan 80% skadar sig på något vis varje år. Diskussion har uppstått bland löpare och forskare kring om barfotalöpning kan förändra biomekaniken och därmed ändra belastningen och minska risken för skador, samt om barfotalöpning kan leda till en förbättrad löpekonomi och påverka löparens prestationer. Syfte: Att undersöka vilken effekt barfotalöpning (inkl. minimalistskor) har på biomekanik mätt med ground reaction force (GRF) och löpekonomi mätt med syreupptagning jämfört med löpning med konventionella skor.  Metod: Systematisk narrativ litteraturöversikt. Litteratursökningen genomfördes i databaserna Pubmed och Cochrane. Studier som var randomiserade kontrollerade studier (RCT) alternativt cross-over studier inkluderades. Kvalitetsgranskning av studierna genomfördes med PEDro och tillförlitligheten av resultatet bedömdes med GRADEstud. Resultat: Åtta artiklar inkluderades, tre om biomekanik och fem om löpekonomi. Inga samstämmiga resultat sågs gällande barfotalöpningens effekter på GRF, en studie påvisade en signifikant minskning medan två studier visade på en signifikant ökning av GRF. Positiva tendenser sågs i studierna om löpekonomi, varav två påvisade signifikanta förbättringar. Kvaliteten på artiklarna bedömdes som måttlig och tillförlitligheten till resultaten bedömdes vara mycket låg.  Konklusion: Barfotalöpning påvisar vissa positiva effekter på löpekonomi medan effekterna på GRF är motstridiga. Tillförlitligheten av evidensen bedömdes vara mycket låg. Det behövs fler högkvalitativa studier som undersöker de långvariga och akuta effekterna av barfotalöpning på löpekonomi och biomekanik för att kunna dra slutsatser och implementera kunskapen bland fysioterapeuter som arbetar med löparskador. / Background: Running is a popular activity in Sweden today. However, injuries are common and almost 80% of runners get injured each year. Discussions about whether barefoot running could alter the biomechanics and decrease the risk of injury, and improve the running economy and increase a runner's performance, has risen amongst runners and researchers. Purpose: To examine the effects of barefoot running (minimalist footwear) on biomechanics measured with ground reaction force (GRF) and running economy measured with oxygen consumption compared to shod running.  Method: A systematic review. Articles were found using the Pubmed and Chochrane database. Randomised controlled trials (RCT) or Cross-over studies were included. Assessment of study quality was measured with the PEDro-scale and the reliability of the result assessed with GRADEstud. Result: Eight articles were included, three about biomechanics and five about running economy. Inconclusive results were found on the effects of barefoot running on GRF, one study showed a significant reduction in GRF and the other two showed increase in GRF. Positive tendencies were found concerning running economy, two studies showed a significant increase. The quality of the studies were moderate and the reliability of the result were very low. Conclusion: Barefoot running showed positive findings on running economy, while the effects on GRF were inconclusive. The evidence was considered very low. There is a need for more high-quality studies examining the long-lasting and acute effects of barefoot running on running economy and biomechanics to be able to draw conclusions and implement the knowledge in clinical physiotherapy.

Behavioural biometrics are unique non-physical human characteristics that can be used to distinguish one person from another. One such characteristic, which belongs to the Gait Biometric, is the footstep Ground Reaction Force (GRF), the temporal signature of the force exerted by the ground back on the foot through the course of a footstep. This is a biometric for which the computational power required for practical applications in a security setting has only recently become available. In spite of this, there are still barriers to deployment in a practical setting, including large research gaps concerning the effect of footwear and stepping speed on footstep GRF-based person recognition. In this thesis we devised an experiment to address these research gaps, while also expanding upon the biometric system research presented in previous GRF recognition studies. To assess the effect of footwear on recognition performance we proposed the analysis of a dataset containing samples for two different types of running shoes. While, with regards to stepping speed, we set out to demonstrate that normalizing for step duration will mitigate speed variation biases and improve GRF recognition performance; this included the development of two novel machine learning-based temporal normalization techniques: Localized Least Squares Regression (LLSR) and Localized Least Squares Regression with Dynamic Time Warping (LLSRDTW). Moreover, building upon previous research, biometric system analysis was done over four feature extractors, seven normalizers, and five different classifiers, allowing us to indirectly compare the GRF recognition results for biometric system configurations that had never before been directly compared. The results achieved for the aforementioned experiment were generally in line with our initial assumptions. Comparing biometrics systems trained and tested with the same footwear against those trained and tested with different footwear, we found an average decrease in recognition performance of about 50%. While, performing LLSRDTW step duration normalization on the data led to a 14-15% improvement in recognition performance over its non-normalized equivalent in our two most stable feature spaces. Examining our biometric system configurations we found that a Wavelet Packet Decomposition-based feature extractor produced our best feature space results with an EER average of about 2.6%, while the Linear Discriminant Analysis (LDA) classifier performed best of the classifiers, about 19% better than any of the others. Finally, while not the intended purpose of our research, the work in this thesis was presented such that it may form a foundation upon which future classification problems could be approached in a wide range of alternative domains. / Graduate / 0800 / 0544 / jericmason@gmail.com

A dissertação tem por objetivo central caracterizar, através de parâmetros biomecânicos e fisiológicos, a corrida de intensidade supramáxima intermitente em situação de fadiga, e o possível efeito da suplementação com creatina sobre esses parâmetros. Para a indução da fadiga, 8 atletas voluntários (16,3 ± 0,5 anos de idade; 1,78 ± 0,059 m de altura, 70,7 ± 4,16 kg de massa) realizaram teste intermitente (i.e. 5 séries de corrida) com carga constante (i.e. 120% da vVo2max -10% de inclinação da esteira) até a exaustão. Logo ao início da primeira série de corrida realizaram-se coletas da Força de Reação do Solo, do sinal eletromiográfico, da frequência cardíaca e da percepção de esforço. Nas séries 2, 3, 4 e 5 tais parâmetros foram novamente coletados em condição de iminente impossibilidade em manter o exercício. Foram realizadas coletas da concentração de lactato antes das 5 séries de corrida, imediatamente após, e depois de 3 e 5min de descanso. Os voluntários realizaram o protocolo de indução de fadiga em três ocasiões distintas: sem suplementação, com placebo, com suplementação de monoidrato de creatina, seguindo o modelo cross-over, uni-cego. Os resultados apontam para uma clara tendência de aumento da carga externa na situação de fadiga, associada a um consistente aumento da pré-atividade muscular. Provavelmente em função das características do protocolo, observou-se que a maioria dos músculos estudados evidenciou uma tendência de redução na intensidade recrutamento muscular durante a fase de apoio em resposta à fadiga. Observou-se, ainda, uma clara tendência de redução da freqüência mediana para os músculos extensores e flexores da coxa em decorrência da fadiga. Ainda que o efeito da suplementação de creatina sobre os parâmetros eletromiográficos não tenha sido claro, observou-se uma significativa redução da sobrecarga mecânica induzida pelas forças externas em resposta a esta suplementação / The main purposes of this study were to provide a biomechanical and physiological characterization of supramaximal intermittent running during fatigue, and also, to investigate the possible effects of creatine supplementation on the running characterization parameters. To induce fatigue, 8 athletes (years of age=16,3 ± 0,5; height=1,78 ± 0,059 m; weight=70,7 ± 4,16 kg) underwent an intermittent running protocol (i.e. 5 running bouts to exhaustion, interspersed by a 90 s interval) at a fixed load (i.e. 120% of the vVO2max 10% treadmill slope). Ground reaction force, electromyographic signal, heart rate and rate of perceived exertion were obtained at the beginning of the first running bout and at the imminence of exercise interruption due to fatigue on the remaining four bouts. Blood lactate concentration was evaluated prior the beginning of the first running bout and immediately after, 3 and 5 min after the completion of the last running bout. The participants underwent the fatigueinducing protocol under three different conditions: no supplementation, placebo, and creatine supplementation in a single-blind cross-over design. Our results suggest that the subjects experienced a higher external load during fatigue, associated to a consistent increase in muscle pre-activity. It is possible to speculate that the protocol characteristics (i.e. supramaximal running) may have influenced the observed decrease in the muscular activity during fatigue. We have also observed a trend for the decrease in the median frequency for the hip flexors and extensors, possibly influenced by fatigue. Even though no significant effects of creatine supplementation on the electromyographical parameters were observed, a significant decrease in the mechanical overload was observed in response to its supplementation

Andar na água tem sido utilizado como um método alternativo para treinamento e reabilitação. No entanto, há pouca informação sobre as características biomecânicas do andar em piscina rasa. Em se tratando de indivíduos idosos, a escassez é ainda maior. Informações sobre as características biomecânicas do andar nessa condição ambiental é importante para um melhor entendimento da tarefa. Sendo assim, características espaço-temporais, cinemáticas, da força de reação do solo (FRS) e eletromiográficas (EMG) de adultos e idosos andando em piscina rasa (ambiente aquático - AA) e fora da piscina (ambiente terrestre - AT) foram investigadas. Para tanto, dez adultos (21-38 anos) e dez idosos (60-77 anos) andaram no AT e em seguida no AA (nível do processo xifóide do esterno) com velocidades auto-selecionadas e confortáveis. Em termos gerais, a maioria das variáveis espaço-temporais da passada foi diferente entre os ambientes e entre os grupos. Porém, enquanto que a velocidade entre os adultos e idosos foi diferente no AT, os dois grupos apresentaram a mesma velocidade para andar no AA. Os ângulos articulares investigados variaram conforme o ambiente e/ou grupo. A magnitude dos picos da componente vertical da FRS foi menor no AA do que no AT e a componente horizontal ântero-posterior apresentou apenas uma fase de aceleração no AA. Por fim, o padrão de ativação EMG foi diferente entre os ambientes para a maioria dos músculos investigados e a magnitude da atividade EMG dos mesmos foi menor no AA. Os resultados encontrados neste estudo contribuem para um melhor entendimento do andar no AA no contexto de treinamento e reabilitação. / Walking in water has been used as an alternative way for both training and rehabilitation. However, there is little information about the biomechanical characteristics of shallow water walking. In terms of elderly individuals, it is even scarcer. Information about the biomechanical characteristics of walking in this environmental condition is important for a better understanding of this task. In this way, spatial-temporal, kinematics, ground reaction force (GRF), and electromyographic (EMG) characteristics of adults and elders walking in shallow water and on land were investigated. As such, ten adults (21-38 years old) and ten elders (60-77 years old) walked on land and then in shallow water (Xiphsternun water level) with self-selected comfortable walking speeds. In general, most stride spatial-temporal variables were different between both environments and groups. Although walking speed was different between adults and the elderly on land, both groups showed the same walking speed in shallow water. The investigated angle joints varied according to environment and/or group. The magnitude of the vertical GRF peaks was lower in shallow water than on land and the anterior-posterior horizontal GRF showed an acceleration phase only in shallow water. Finally, the EMG activation pattern was different for most investigated muscles and the EMG activity magnitude of those was smaller in shallow water than on land. The results in the present study contribute to a better understanding of this activity in the context of training and rehabilitation.

Esta tese objetivou investigar as características biomecânicas da corrida com mínima proteção para a planta do pé, bem como o efeito do treinamento sob estas condições sobre o aparelho locomotor. Para isso, 3 experimentos foram realizados: o experimento 1 caracterizou a realização da corrida e o efeito do treinamento com os pés descalços sobre parâmetros biomecânicos da corrida; o experimento 2 testou o efeito da transição de 4 meses do calçado tradicional para o minimalista, manipulando-se o calçado esportivo; e o experimento 3 comparou indivíduos habituados ao uso do calçado com indivíduos habituados a movimentos em condições de mínima proteção. Uma esteira equipada com plataformas de força (Sistema Gaitway) e um eletromiógrafo (EMG 1000 Sistema Lynx) foram utilizados para a aquisição dos dados biomecânicos. Agudamente, os 3 experimentos mostraram interferência negativa da proteção plantar reduzida sobre parâmetros da força de reação do solo (FRS). Contudo, no experimento 1 observou-se possibilidade de menor ocorrência de primeiro pico da FRS em indivíduos habituados a movimentos com mínima proteção, significando sobrecarga externa reduzida. Os experimentos 1 e 2 evidenciam melhora do controle de sobrecarga externa em função de 4 meses de treinamento com mínima proteção, diminuindo em até 54,4% o choque mecânico. Conclui-se que, forma aguda e em indivíduos não adaptados, as condições de mínima proteção podem interferir negativamente no movimento e no controle das cargas externas, aumentando a sobrecarga imposta ao aparelho locomotor durante a corrida. Contudo, a experiência em mínima proteção, principalmente adotada de forma crônica e específica, influencia positivamente o gerenciamento das cargas mecânicas, melhorando o controle de choque e rendimento / This thesis aimed to investigate the biomechanical characteristics of running with minimal protection for the foot, as well as the training effects upon the human body under this condition. For that, three experiments were performed: experiment 1 compared individuals accustomed to the use of footwear with individuals accustomed to motor tasks in conditions of minimal protection; the second experiment characterized the running barefoot and the effects of 4-month training barefoot upon its biomechanical parameters; and experiment 3 tested the effects of 4-month transition from traditional running shoe to the minimalist shoe, only manipulating the footwear. A treadmill equipped with force platforms (System Gaitway) and an electromyography (EMG 1000 - Lynx System) were used to measure the biomechanical variables. Acutely, the 3 experiments showed negative interference of minimal protection upon parameters of the ground reaction force (GRF). However, the experiment 1 presented the possibility of lower first peak of GRF occurrence in the participants who are adapted to minimal protection condition, what means decreased external load. The experiments 2 and 3 showed improvements in the external forces control as a response to 4 months of adaptation in minimal protection running, what could decrease about 54,4% of mechanical stress. In conclusion, the minimal protection condition can negatively influence the movement and stress control in a acute way and in individuals who are not adapted to minimal protection condition, increasing the overload imposed to human body during running. However, the adaptation to minimal protection condition, mainly in a chronicle and specific way, exert a positive influence upon the management of mechanical loads, improving impact control and performance

O objetivo desse estudo é: (a) verificar o efeito do desgaste do calçado na Força de Reação do Solo (FRS) e na distribuição de pressão plantar e (b) verificar a influência do desgaste em calçados de diferentes destinações de uso. Três sujeitos participaram desse estudo, usando cada um quatro calçados de corrida, sendo dois de treinamento (T1 e T2) e dois de competição (C1 e C2). Os calçados foram submetidos ao uso correspondente a 300km. As coletas de dados foram feitas, com o calçado novo e após 100, 200 e 300km de uso, utilizando o sistema Gaitway e o sistema F-Scan. Nos calçados novos, na FRS, a Taxa de Crescimento1 (TC1) foi significativamente maior no calçado C2, do que nos calçados C1 e T2. Na distribuição de pressão plantar, pequena diferença foi observada na Área total (AT) e nos picos de pressão, entre os calçados. Na influência do desgaste nos resultados de grupo, na FRS, o TC1 apresentou valores semelhantes entre as condições Novo e 300km, portanto o choque mecânico não se alterou. Na fase ativa da FRS, oscilações pequenas foram observadas e atribuídas a possíveis variações naturais do movimento, conforme descrito por SERRÃO (1999) e WINTER (1991). Na distribuição de pressão, a AT apresentou um aumento significativo da condição Novo, para as demais condições de uso. O aumento da área foi atribuído à possível compactação do calçado, sendo que essa alteração justificaria a crença de que o calçado novo precise ser amaciado. Entre os picos de pressão analisados, apenas o Pico de Pressão do Antepé (PPA) apresentou diminuição significativa nos valores, da condição Novo para os 300km. Observou-se que após o desgaste imposto, o estresse mecânico se manteve ou se apresentou menor que nas condições iniciais. Na análise da influência do desgaste nos diferentes calçados, para TC1, as diferenças que inicialmente eram significativas tornaram-se não significativas, a partir dos 200km, entre os calçados C1, C2 e T2. Os parâmetros da fase ativa foram pouco influenciados, porém influenciados de forma distinta pelo desgaste, nos calçados analisados. Na distribuição de pressão plantar, a área de contato foi influenciada de forma distinta em cada calçado. Nos picos de pressão plantar, grandes variações foram observadas, porém não atribuíveis ao desgaste promovido no calçado. Conclui-se que o desgaste, correspondente a 300km, pouco alterou o choque mecânico e o estresse mecânico nos calçados analisados. Por meio da destinação de uso, não é possível prever a resposta de calçados de treinamento e de competição ao indivíduo, nem supor que a durabilidade do calçado de competição seja menor do que a do calçado de treinamento / The objective of this study is: (a) to verify the effect of footwear usage on the Ground Reaction Force (GRF) and on the Plantar Pressure Distribution and (b) to verify the influence of usage in footwear of different destinations of use. Three subjects had participated of this study, each one received four running shoes, two of them are designated for training regimen (T1 and T2) and two of them for competition (C1 and C2). The footwears were used for 300km. The data collections were made in four different moments, with new footwear and after 100, 200 and 300km of use, using the Gaitway system and the F-Scan system. When footwear was new, the Loading Rate1 (LR1) was significantly higher in footwear C2, than in the footwears C1 and T2. Analyzing plantar pressure distribution, small differences were observed in the Total Contact Area (TCA) and in the peak of pressure, between the footwears. In the analysis of the different usage stages, the LR1 presented similar values between the conditions New and 300km, therefore the mechanical shock did not enhanced. In the active phase of the GRF, small oscillations were observed and attributed to the possible natural variations of the movement itself, as described before by SERRÃO (1999) and WINTER (1991). In pressure distribution, the TCA showed a significant increase from the New condition, for the other conditions of use. The increase of contact area was attributed to the possible compactation of the footwear?s material, if so this would justify the belief that the new footwear needs to be softened. Considering all peak pressure variables, only Forefoot Peak Pressure (FPP) presented significant reduction in its values, from the New condition for 300km. Therefore it could be assumed that after corresponding usage of 300km, the mechanical stress remained the same or decreased compared with the earlier conditions of use. The shoes of different destinations when analyzed through the conditions, showed that the differences for LR1 that initially were significant had become not significant, from 200km, between the footwear C1, C2 and T2. In the pressure peaks plantar, great variations had been observed, however not attributable to the usage. The conclusion is that usage, correspondent 300km, has little effect on mechanical shock and on mechanical stress on the footwear analyzed in this study. By means of the use destination, it is not possible to foresee the answer of footwear to the individual, nor to assume that the durability of the footwear are worse in competition shoes than in training shoes

O objetivo deste estudo foi determinar a influência das características de três tipos de mochila através de parâmetros biomecânicos e fisiológicos selecionados. Foram voluntários 49 carteiros (30±7 anos, 1,74±0,62 m e 72,6±11,8 kg), que utilizaram 3 tipos de mochilas: mochila lateral simples (MLS), mochila lateral com cinto pélvico (MLCP) e mochila dupla com cinto pélvico (MDCP). Os sujeitos andaram durante 10 minutos sobre esteira rolante Trotter instrumentada com duas plataformas de força de reação do solo Kistler, utilizando um analisador de gases que analisou os gases expirados. As variáveis cinéticas da locomoção apresentaram diferenças significativas entre as mochilas. As variáveis cinemáticas não mostraram diferenças significativas. A ventilação apresentou diferenças entre MLCP (23,2±5,4 L · min-1) e MLS (22,5±5,0 L · min-1) e MDCP (22,3±4,8 L · min-1) e o consumo de oxigênio apresentou diferenças entre MDCP (14,6±4,1 mL · kg-1 · min-1) e MLS (15,1±3,6 mL · kg-1 · min-1) e MLCP (15,2±4,3 mL · kg-1 · min-1). Os dados dinâmicos apontaram para benefícios do uso da MLS, e os dados fisiológicos apontaram para benefícios do uso da MDCP. Embora os dados tenham apresentado diferenças estatísticas, estas não foram de magnitudes representativas, assim, a MDCP parece induzir maior demanda metabólica e a MLS menor estresse físico. / The aim of this study was to determine the influence of the satchel construction characteristics in selected biomechanical and physiological parameters during the accomplishment of the locomotion of mailmen pedestrians. 49 mailmen had been voluntary (30±7 years, 1.74±0.62 m and 72.6±11.8 kg), which had used 3 types of satchels, simple lateral satchel (MLS), lateral satchel with pelvic belt (MLCP) and double satchel with pelvic belt (MDCP). The subjects had walked 10 minutes on Trotter treadmill instrumented with two Kistler force platforms, using a gas analyzer that made analyzes of the exhaled gases. Fy1 presented differences between MLS (1.35±0.10) and MLCP (1.37±0.11) and MDCP (1.37±0.10), like others FRS parameters. The step and strike lengths had not been sensible to the different satchels. The VE presented differences between MLCP (23.2±5.4 L · min-1) and MLS (22.5± 5.0 L · min-1) and MDCP (22.7±4.8 L · min-1) and the VO2, presented differences between MDCP (14.6± .1 mL · kg-1 · min-1) and MLS (15.1±3. 6 mL · kg-1 · min-1) and MLCP (15.2±4.3 mL · kg-1 · min-1). The dynamic data had pointed to benefits using MLS, but the physiological data had indicated to benefits using MDCP. Although the data have presented statistical differences, but these had not been representative magnitudes, thus, the MDCP seems to induce bigger metabolic demand and MLS the lesser physical stress.

Three dimensional (3D) ground reaction force (GRF) are an essential component for gait analysis. Current methods for measuring 3D GRF involve using a stationary force plate embedded in the ground, which captures the forces as subjects walk across the platform. This approach has several limitations, a few being: it can only capture a few steps at a time, it is expensive to purchase and maintain, it can't reflect forces caused by natural uneven surfaces, etc. Previous research has attempted to develop wearable force sensors to overcome these problems; however, these endeavors have resulted in devices that are expensive, bulky, and fail to accurately measure forces when compared to static force plates. This thesis presents the implementation and validation of novel nanocomposite piezoresponsive foam (NCPF) sensors for measuring 3D GRF. Four NCPF sensors were embedded in a shoe sole at four locations: heel, arch, ball, and toe. The signals from each sensor were used in a functional data analysis (FDA) to develop a statistical model for estimating 3D GRF. The process of calibrating the sensors to model GRF was validated through a study where 9 subjects (4 females, 5 males) walked on a force-sensing treadmill for two minutes. Two approaches were used to model the GRF response. The first approach was based on functional decomposition of the data. Using a tenfold cross validation process a statistical model was developed for each subject with the ability to predict walking 3D GRF with less than 7% error. The second approach used machine learning to model 3D GRF. Using the same walking data for the statistical models, an artificial neural network (ANN) was used to create subject-specific models that could predict walking 3D GRF with less than 11% error. The predictive capabilities of ANN were tested using a pilot study where a single subject performed a calibration procedure by running at seven different speeds for thirty seconds each on the force-sensing treadmill. This calibration data was used to train a model, which was then used to estimate vertical GRF (VGRF) for three additional running trials at randomly selected speeds from within the calibration range. The ANN model was able to predict VGRF for three running speeds after calibration with less than 4% error. The use of NCPF sensors to estimate 3D GRF was shown to be a viable alternative to static force plates. It is recommended, in future work, that 3D GRF and subsequent sensor data be collected from a large sample of subjects to create a baseline of 3D GRF characteristics for a population that will enable a robust cross-subject model capable of performing real-time ground reaction force analysis across the general population, which will greatly benefit our understanding of human gait.

Examining a countermovement jump (CMJ) force-time curve related to net impulse might be useful in monitoring athletes' performance. This study aimed to investigate the reliability of alternative net impulse calculation and net impulse characteristics (height, width, rate of force development, shape factor, and proportion) and validate against the traditional calculation in the CMJ. Twelve participants performed the CMJ in two sessions (48 hours apart) for test–retest reliability. Twenty participants were involved for the validity assessment. Results indicated intra-class correlation coefficient (ICC) of ≥ 0.89 and coefficient of variation (CV) of ≤ 5.1% for all of the variables except for rate of force development (ICC = 0.78 and CV = 22.3%). The relationship between the criterion and alternative calculations was r = 1.00. While the difference between them was statistically significant (245.96 ± 63.83 vs. 247.14 ± 64.08 N s, p < 0.0001), the effect size was trivial and deemed practically minimal (d = 0.02). In conclusion, variability of rate of force development will pose a greater challenge in detecting performance changes. Also, the alternative calculation can be used practically in place of the traditional calculation to identify net impulse characteristics and monitor and study athletes' performance in greater depth.

Objectives: The purpose of this study was to identify the relationship between isometric force production symmetry and jumping performance in weighted and un-weighted static and countermovement jumps (SJ and CMJ). Design: Bivariate correlation between isometric force production symmetry and vertical jump performance variables. Methods: Collegiate athletes were evaluated for this study (n=36). Subjects performed SJ, CMJ, and isometric mid-thigh pulls (IMTP). Jumps were analyzed for jump height (JH) and peak power (PP). IMTP was analyzed for peak force (PF) for left and right sides, and values were calculated to produce a peak force symmetry index (PF-SI) score. Correlational statistics were performed examining the relationship between PF-SI and jump variables. Results: Moderate statistically significant negative correlations were observed between PF-SI and all jump variables, indicating that as asymmetry increases jump performance decreases. SJ correlations weakened in weighted conditions (JH r=-0.52 @ 0 kg/r=-0.39 @ 20 kg, PP r=-0.43 @ 0 kg/r=-0.34 @ 20 kg), but CMJ produced similar correlations for both conditions (JH r=-0.47 @ 0 kg/r=-0.49 @ 20 kg, PP r=-0.28 @ 0 kg/r=-0.34 @ 20 kg). Unlike the SJ, which only contains the propulsive or concentric portion of the jump, the CMJ also contains the eccentric portion and performance contributions of the stretch-shortening cycle (SSC). The addition of the SSC may play a role in the maintaining the magnitude of asymmetry in the CMJ weighted condition. Conclusions: The results indicate that force production asymmetry may be detrimental to bilateral vertical jumping performance. The findings should be considered for further investigation on sport-specific tasks.