Relationship Between Advanced Footwear Technology Longitudinal Bending Stiffness and Energy Cost of Running.

INTRODUCTION/PURPOSE: Shoe longitudinal bending stiffness (LBS) is often considered to influence running economy (RE) and thus, running performance. However, previous results are mixed and LBS levels have not been studied in advanced footwear technology (AFT). The purpose of this study was to evaluate the effects of increased LBS from curved carbon fiber plates embedded within an AFT midsole compared to a traditional running shoe on RE and spatiotemporal parameters. METHODS: Twenty-one male trained runners completed three times 4 min at 13 km/h with two experimental shoe models with a curved carbon fiber plate embedded in an AFT midsole with different LBS values (Stiff: 35.5 N/mm and Stiffest: 43.1 N/mm), and a Control condition (no carbon fiber plate: 20.1 N/mm). We measured energy cost of running (W/kg) and spatiotemporal parameters in one visit. RESULTS: RE improved for the Stiff shoe condition (15.71 ± 0.95 W/kg; p < 0.001; n2 = 0.374) compared to the Control condition (16.13 ± 1.08 W/kg; 2.56%) and Stiffest condition (16.03 ± 1.19 W/kg; 1.98%). However, we found no significant differences between the Stiffest and Control conditions. Moreover, there were no spatiotemporal differences between shoe conditions. CONCLUSION: Changes in LBS in AFT influences RE suggesting that moderately stiff shoes have the most effective LBS to improve RE in AFT compared to very stiff shoes and traditional, flexible shoe conditions while running at 13 km/h.

Acute physiological, biomechanical, and perceptual responses of runners wearing downward-curved carbon fiber insoles.

In a randomized controlled cross-over study ten male runners (26.7 ± 4.9 years; recent 5-km time: 18:37 ± 1:07 min:s) performed an incremental treadmill test (ITT) and a 3-km time trial (3-km TT) on a treadmill while wearing either carbon fiber insoles with downwards curvature or insoles made of butyl rubber (control condition) in light road racing shoes (Saucony Fastwitch 9). Oxygen uptake, respiratory exchange ratio, heart rate, blood lactate concentration, stride frequency, stride length and time to exhaustion were assessed during ITT. After ITT, all runners rated their perceived exertion, perceived shoe comfort and perceived shoe performance. Running time, heart rate, blood lactate levels, stride frequency and stride length were recorded during, and shoe comfort and shoe performance after, the 3-km TT. All parameters obtained during or after the ITT did not differ between the two conditions [range: p = 0.188 to 0.948 (alpha value: 0.05); Cohen's d = 0.021 to 0.479] despite the rating of shoe comfort showing better scores for the control insoles (p = 0.001; d = -1.646). All parameters during and after the 3-km TT showed no differences (p = 0.200 to 1.000; d = 0.000 to 0.501) between both conditions except for shoe comfort showing better scores for control insoles (p = 0.017; d = -0.919). Running with carbon fiber insoles with downwards curvature did not change running performance or any submaximal or maximal physiological or biomechanical parameter and perceived exertion compared to control condition. Shoe comfort is impaired while running with carbon fiber insoles. Wearing carbon fiber insoles with downwards curvature during treadmill running is not beneficial when compared to running with control insoles.

Influence of different midsole foam in advanced footwear technology use on running economy and biomechanics in trained runners.

BACKGROUND: Ethylene and vinyl acetate (EVA) and polyether block amide (PEBA) are recently the most widely used materials for advanced footwear technology (AFT) that has been shown to improve running economy (RE). This study investigated the effects of these midsole materials on RE and biomechanics, in both fresh and worn state (after 450 km). METHODS: Twenty-two male trained runners participated in this study. Subjects ran four 4-min trials at 13 km‧h-1 with both fresh EVA and PEBA AFT and with the same models with 450 km of wear using a randomized crossover experimental design. We measured energy cost of running (W/kg), spatiotemporal, and neuromuscular parameters. RESULTS: There were significant differences in RE between conditions (p = 0.01; n2 = 0.17). There was a significant increase in energy cost in the worn PEBA condition compared with new (15.21 ± 1.01 and 14.87 ± 0.99 W/kg; p < 0.05; ES = 0.54), without differences between worn EVA (15.13 ± 1.14 W/kg; p > 0.05), and new EVA (15.15 ± 1.13 w/kg; ES = 0.02). The increase in energy cost between new and worn was significantly higher for the PEBA shoes (0.32 ± 0.38 W/kg) but without significant increase for the EVA shoes (0.06 ± 0.58 W/kg) (p < 0.01; ES = 0.51) with changes in step frequency and step length. The new PEBA shoes had lower energy cost than the new EVA shoes (p < 0.05; ES = 0.27) with significant differences between conditions in contact time. CONCLUSION: There is a clear RE advantage of incorporating PEBA versus EVA in an AFT when the models are new. However, after 450 km of use, the PEBA and EVA shoes had similar RE.

The Role of Footwear, Foot Orthosis, and Training-Related Strategies in the Prevention of Bone Stress Injuries: A Systematic Review and Meta-Analysis.

Objective: To evaluate the effectiveness of footwear, foot orthoses and training-related strategies to prevent lower extremity bone stress injury (BSI). Design: Systematic review and meta-analysis. Data sources: Four bibliographic databases (from inception until November 2021): Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and CINAHL. Eligibility criteria: Randomised controlled trials (RCTs) that assessed the risk of developing a BSI when using particular footwear, foot orthoses or training-related strategies such as muscle strengthening, stretching, and mechanical loading exercises. Results: Eleven studies were included in this systematic review. When wearing foot orthoses, the risk ratio of developing a BSI on any lower extremity bone is 0.47 (95% CI 0.26 to 0.87; p = 0.02). When doing pre-exercise dynamic stretching, the risk ratio of suffering a tibial BSI is 1.06 (95% CI 0.67 to 1.68; p = 0.79). No meta-analyses could be performed for footwear or training-related strategies. The quality of evidence for all these results is low considering the high risk of bias in each study, the low number of studies and the low number of cases in each study. Conclusion: This systematic review reveals the lack of high-quality studies in BSI prevention. Based on studies at high risk of bias, foot orthoses could potentially help prevent BSIs in the military setting. It is still unknown whether footwear and training-related strategies have any benefits. It is crucial to further investigate potential BSI prevention strategies in women and athletes. Research is also needed to assess the influence of running shoes and loading management on BSI incidence.

Simulation of Lower Limb Muscle Activation Using Running Shoes with Different Heel-to-Toe Drops Using Opensim.

BACKGROUND: Although numerous studies have been conducted to investigate the acute effects of shoe drops on running kinematics and kinetic variables, their effects on muscle forces remain unknown. Thus, the primary aim of this study was to compare the muscle force, kinematics, and kinetic variables of habitually rearfoot runners with heel-to-toe drops of negative 8 mm shoes (minimalist shoes) and positive 9 mm shoes (normal shoes) during the running stance phase by using musculoskeletal modeling and simulation techniques. METHODS: Experimental data of lower limb kinematics, ground reaction force, and muscle activation from 16 healthy runners with rearfoot strike patterns were collected and analyzed in OpenSim. Using Matlab, the statistical parameter mapping paired t-test was used to compare the joint angle, moment, and muscle force waveform. RESULTS: The results revealed differences in the sagittal ankle and hip angles and sagittal knee moments between the different heel-to-toe drops of running shoes. Specifically, it showed that the negative 8 mm running shoes led to significantly smaller values than the positive 9 mm running shoes in terms of the angle of ankle dorsiflexion, ankle eversion, knee flexion, hip flexion, and hip internal and hip external rotation. The peak ankle dorsiflexion moment, ankle plantarflexion moment, ankle eversion moment, knee flexion moment, knee abduction moment, and knee internal rotation also decreased obviously with the minimalist running shoes, while the lateral gastrocnemius, Achilleas tendon, and extensor hallucis longus muscles were obviously greater in the minimalist shoes compared to normal shoes. The vastus medialis, vastus lateralis and extensor digitorum longus muscles force were smaller in the minimalist shoes. CONCLUSIONS: Runners may shift to a midfoot strike pattern when wearing negative running shoes. High muscle forces in the gastrocnemius lateral, Achilleas tendon, and flexor hallucis longus muscles may also indicate an increased risk of Achilleas tendonitis and ankle flexor injuries.

Marathon shoes vs. track spikes: a crossover pilot study on metabolic demand at different speeds in experienced runners.

The aim of this study was to assess the metabolic cost (Cr) with marathon shoes (Adidas Adizero 3 [AA]) vs. track spikes (Nike Zoom Matumbo 3 [NZM]) on track. For this, five experienced runners were randomly assessed (NZM/AA) on a running track at 73% and 85% of best performance speed on 1500-m race. At first, speed (4.39 ± 0.53 m·s-1), Crs with AA and NZM resulted 3.63 ± 0.29 and 3.64 ± 0.43 J·kg-1·m-1 (+0.3% with NZM, effect size [ES] small and p = 0.951), respectively. Besides, at second speed (5.20 ± 0.18 m·s-1), Crs were 4.09 ± 0.28 and 4.07 ± 0.22 J·kg-1·m-1 (-0.5% with NZM, ES small and p = 0.919) with AA and NZM, respectively. It resulted in an increased Cr (+12.2%) between s1 and s2 with both shoe conditions (ES large and p = 0.009 and 0.011 with AA and NZM, respectively). There is a pattern yet to be confirmed for track spikes to become more beneficial at higher speeds (when duty factor becomes lower and therefore grip on track is crucial).

A systematic review of the effect of running shoes on running economy, performance and biomechanics: analysis by brand and model.

This systematic review aims to synthesise the effects of current shoe models in each shoe category and their specific features on running economy, performance and biomechanics. Electronic databases such as Web of Science, SPORTDiscuss, PubMed and Scopus were used to identify studies from 2015 to date. Due to the existing lack of consensus to define running shoes, only studies that specified the shoe brand and models used to assess their effect over runners with a certain level of fitness and training routine were included. Quality assessment of cross-sectional and intervention studies was conducted by three independent raters using a modified version of the Quality Index and the PEDro scale, respectively. A total of 36 articles were finally included, involving the analysis of 61 different shoe models over 10 different topics (i.e., running economy, running performance, spatiotemporal parameters, ground reaction forces, joint stiffness, achilles tendon, plantar pressure, tibiofemoral load, foot strike pattern and joint coordination). With this review, runners and practitioners in the field that are concerned about selecting a suitable shoe for performance, training, or injury prevention functionality have clear information about the effects of the current shoe models and their specific features.

Acute effects of footwear on running impact loading in the preschool years.

The aim of this study was to assess acute effects of footwear conditions (barefoot, minimalist and standard running shoes) on running impact loading in the preschool years. Fourty-eight habitually shod preschool children (26 males and 22 females) were divided into four age groups (3-, 4-, 5- and 6-year-old). Children performed a simple running game in three different conditions. Three-dimensional biomechanical analysis was carried out during overground running. Statistical parametric mapping was performed on the vertical ground reaction force profiles during the stance phase and one-way repeated measures ANOVA on the vertical instantaneous loading rate. Three-year-old children displayed significantly lower vertical ground reaction force values in the barefoot condition compared to minimalist (3-7% stance) and standard running shoes (7-11% stance). There were also differences in vertical instantaneous loading rate, where 3-year-olds had lower loading when barefoot than in minimalist (p = 0.010, d = 1.19) or running shoes (p = 0.045, d = 0.98), despite no differences in the footstrike pattern (mostly rearfoot-midfoot strike). No differences were found for the older children. Running in minimalist shoes did not imitate barefoot running in 3-year-old children. On the contrary, increased loading was observed in minimalist shoes in early running developmental stages.

The Implications of Sports Biomechanics Studies on the Research and Development of Running Shoes: A Systematic Review.

Although various sports footwear demonstrated marked changes in running biomechanical variables, few studies have yielded definitive findings on the underlying mechanisms of shoe constructions affecting running-related performance and injuries. Therefore, this study focused on examining the effect of basic shoe constructions on running biomechanics and assessing the current state of sports shoe production in terms of injury and efficiency. Relevant literature was searched on five databases using Boolean logic operation and then screened by eligibility criteria. A total of 1260 related articles were retrieved in this review, and 41 articles that met the requirements were finally included, mainly covering the influence of midsole, longitudinal bending stiffness, heel-toe drop, shoe mass, heel flare, and heel stabilizer on running-related performance and injuries. The results of this review study were: (1) The functional positioning of running shoe design and the target groups tend to influence running performance and injury risk; (2) Thickness of 15-20 mm, hardness of Asker C50-C55 of the midsole, the design of the medial or lateral heel flares of 15°, the curved carbon plate, and the 3D printed heel cup may be beneficial to optimize performance and reduce running-related injuries; (3) The update of research and development concepts in sports biomechanics may further contribute to the development of running shoes; (4) Footwear design and optimization should also consider the influences of runners' strike patterns.

A escolha do calçado por corredores amadores: caracterização e associação com o histórico de lesão auto reportada / La elección del calzado por los corredores aficionados: caracterización y asociación con el historial de lesiones autoinformado / Selection of running shoes by amateur runners: characterization and association with the self-reported history of injury

RESUMO O calçado é um elemento importante para a prática de corrida. As evidências sobre os impactos das características do calçado e de sua prescrição nas lesões de corredores são restritas. Dessa forma, os objetivos deste estudo foram investigar o processo de escolha do calçado por corredores e verificar se variáveis relacionadas ao calçado e seu processo de escolha estavam associadas à presença e recorrência de lesão no último ano. Foi realizado um estudo observacional com 254 corredores que responderam um questionário autoadministrado sobre características demográficas, a prática esportiva, o calçado e o processo de sua escolha, e lesões ocorridas nos últimos 12 meses. O teste qui-quadrado foi empregado para verificar se havia diferença na distribuição das respostas de cada questão, enquanto o teste de regressão logística para verificar se as variáveis relacionadas ao calçado e ao processo de escolha predizem a presença e recorrência de lesão no último ano. Os resultados indicaram que a maioria dos corredores possui tênis específico para a prática esportiva e considera algumas características ao adquiri-lo, como o amortecimento intermediário e a diferença na altura do solado entre a parte posterior e a anterior de aproximadamente 10mm. A maioria indica conhecer seu tipo de pisada, mas não a considera na escolha do calçado. Além disso, a maioria não usa palmilha e não recebeu orientação para a escolha do calçado. O modelo obtido com a regressão não foi significativo. Assim, apesar de os corredores considerarem as características do calçado ao adquiri-lo, essas características e o processo de escolha não foram associados à presença e recorrência de lesão nos últimos 12 meses.

RESUMEN El calzado es un elemento importante para la práctica deportiva de carrera. Sin embargo, es limitada la evidencia sobre los impactos de las características del calzado deportivo y su prescripción sobre las lesiones en los corredores. Por lo tanto, los objetivos de este estudio fueron investigar el proceso de elección de calzado por los corredores y verificar si las variables relacionadas con el calzado y su proceso de elección se asociaron con la presencia y recurrencia de lesiones en el último año. Se realizó un estudio observacional con 254 corredores que respondieron un cuestionario autoinformado sobre las características demográficas, la práctica deportiva, el calzado y el proceso de elección, y las lesiones que se llevaron a cabo en los últimos 12 meses. La prueba de chi-cuadrado se aplicó para verificar la existencia de diferencias en la distribución de respuestas para cada pregunta. Y se utilizó la prueba de regresión logística para determinar si las variables relacionadas con el calzado y su proceso de elección pueden predecir la presencia y recurrencia de lesiones en el último año. Los resultados indicaron que la mayoría de los corredores tienen zapatillas adecuadas para hacer deporte y consideran algunas características a la hora de adquirirlas, como una amortiguación intermedia y la diferencia de altura de la suela entre la parte delantera y la trasera de aproximadamente 10mm. La mayoría afirma conocer el tipo de paso, pero no lo considera a la hora de elegir el calzado. Además, la mayoría no utiliza plantillas y no recibe orientación sobre la elección del calzado. El modelo que se obtuvo con la regresión no fue significativo. Por lo tanto, aunque los corredores tienen en cuenta las características del calzado a la hora de adquirirlo, esas características y el proceso de elección no se asociaron con la presencia y recurrencia de lesión en los últimos 12 meses.

ABSTRACT Running shoes are an essential element for sports practice. Evidence on the effect of the shoe characteristics and prescription in running injuries are scarce. Thus, this study aimed to investigate runners's process of choosing running shoes and to verify whether the variables related to running shoes and their selection process are associated with the presence and recurrence of injuries in the previous year. An observational study was conducted with 254 runners who answered a self-reported questionnaire about demographics, sports practice, shoe characteristics and selection criteria, and injuries in the last 12 months. The chi-square test evaluated whether there was a difference in the distribution of answers to each question. The logistic regression evaluated whether the variables related to shoes and selection criteria predicted injury's presence and recurrence in the previous year. The results showed that most runners had specific shoes for sports practice and considered some characteristics of the shoes to choose them, including intermediate cushioning and a difference in the heel-to-toe drop of approximately 10mm. Most respondents indicated knowing their foot type but not considering it when choosing shoes. Besides, most individuals did not use foot orthotics and did not receive guidance to select their shoes. The model obtained with the regression was not significant. Therefore, despite considering shoe characteristics when choosing it, these features and the selection criteria were not associated with the presence and recurrence of injuries in the previous 12 months.

Effects of footwear with different longitudinal bending stiffness on biomechanical characteristics and muscular mechanics of lower limbs in adolescent runners.

Background: Running shoes with carbon plates have been identified to have positive effects on improving running performance from a biomechanical perspective. However, the specific difference between the effects of carbon plates with different longitudinal bending stiffness (LBS)on biomechanical characteristics and muscular mechanics of lower limbs in adolescent runners remains unclear. This study aimed to identify the difference in biomechanical characteristics and muscular mechanics in lower limbs during running stance phases between wearing shoes with low longitudinal bending stiffness (Llbs) and high longitudinal bending stiffness (Hlbs) carbon plates in adolescent runners. Methods: 10 male adolescent runners with a habit of daily running exercise (age: 13.5 ± 0.6 years; height: 166.3 ± 1.9 cm; bodyweight: 50.8 ± 3.1 kg; foot length: 25.4 ± 0.2 cm) were recruited and asked to conduct two times of tests by wearing shoes with Llbs and Hlbs carbon plates in a randomized order. Paired t-test and statistical parametric mapping (SPM) analysis were used to identify the difference in biomechanical characteristics and muscular mechanics in lower limbs during running stance phases. Result: Under the condition of wearing shoes with Hlbs, the time of foot contact significantly increased, whereas the range of motion (ROM) of hip and metatarsophalangeal (MTP) in the sagittal plane significantly reduced as well as the peak moment of ankle joint in the sagittal plane. The activations of vastus medialis, vastus lateralis, flexor digitorum brevis (flex dig brevis), and flexor hallucis longus (flex hall long) significantly increased under the condition of wearing shoes with Hlbs. According to the results of the SPM analysis, the joint angles (hip, ankle, and MTP), the net joint moments (knee, ankle, and MTP), and the muscle forces (gluteus maximus and tibialis anterior) were significant difference during the running stance phase between conditions of wearing shoes with Hlbs and Llbs. Conclusion: Running shoes with Llb carbon plates are appropriate for adolescent runners due to the advantages of biomechanical characteristics and muscular mechanics.

Systematic reduction of leg muscle activity throughout a standard assessment of running footwear.

PURPOSE: This study aimed to investigate whether there is a systematic change of leg muscle activity, as quantified by surface electromyography (EMG), throughout a standard running footwear assessment protocol at a predetermined running speed. METHODS: Thirty-one physically active adults (15 females and 16 males) completed 5 testing rounds consisting of overground running trials at a speed of 3.5 m/s. The level of muscle activity from 6 major leg muscles was recorded using surface EMG. The variables assessed were the EMG total intensity as a function of time and the cumulative EMG overall intensity. Systematic effects of the chronological testing round (independent variable) on the normalized EMG overall intensity (dependent variable) were examined using Friedman analysis of variates and post hoc pairwise Wilcoxon signed-rank tests (α = 0.05). RESULTS: There was a systematic reduction in overall EMG intensity for all 6 muscles over the time course of the running protocol (p < 0.001) until the fourth testing round when EMG intensities reached a steady state. The one exception was the biceps femoris muscle, which showed a significant reduction of EMG intensity during the stance phase (p < 0.001) but not the swing phase (p = 0.16). CONCLUSION: While running at a predetermined speed, the neuromuscular system undergoes an adaptation process characterized by a progressive reduction in the activity level of major leg muscles. This process may represent an optimization strategy of the neuromuscular system towards a more energetically efficient running style. Future running protocols should include a familiarization period of at least 7 min or 600 strides of running at the predetermined speed.

Age differences in running biomechanics during footstrike between preschool children and adults.

This study aimed to compare impact loading between two age groups of preschool children (3-4 and 5-6 years old) and one group of young adults representing mature level of running skill (n = 15 per group). Three-dimensional biomechanical data were collected during running barefoot, in minimalist and running shoes. A two-way mixed ANOVA was performed to assess age and footwear differences in vertical instantaneous loading rate (VILR). An interaction was found in VILR. Older (5-6) preschoolers had 30-31% lower VILR than younger (3-4) (p = 0.012, d = 1.02; p = 0.001, d = 1.18) and adults had 51-77% lower VILR than younger preschoolers (p = 0.001, d = 1.85; p = 0.001, d = 2.82) in minimalist and running shoes, respectively. Additionally, adults had lower VILR than older preschoolers in running shoes (p = 0.001, d = 2.68). No differences were found between older children and adults in barefoot and minimalist shoes. Loading decreased with increasing age, particularly in minimalist and running shoes. Unchanged cadence and running speed did not explain the decrease of VILR during preschool age. The explanation likely underlies in lower limb alignment during footstrike and developmental ontogenetic changes.

Effect of the Construction of Carbon Fiber Plate Insert to Midsole on Running Performance.

In this paper, to investigate the independent effect of the construction of the forefoot carbon-fiber plate inserted to the midsole on running biomechanics and finite element simulation, fifteen male marathon runners were arranged to run across a runway with embedded force plates at two specific running speeds (fast-speed: 4.81 ± 0.32 m/s, slow-speed: 3.97 ± 0.19 m/s) with two different experimental shoes (a segmented forefoot plate construction (SFC), and a full forefoot plate construction (FFC)), simulating the different pressure distributions, energy return, and stiffness during bending in the forefoot region between the SFC and FFC inserted to midsole. Kinetics and joint mechanics were analyzed. The results showed that the footwear with SFC significantly increased the peak metatarsophalangeal joint (MTPJ) plantarflexion velocity and positive work at the knee joint compared to the footwear with FFC. The results about finite element simulation showed a reduced maximum pressure on the midsole; meanwhile, not significantly affected was the longitudinal bending stiffness and energy return with the SFC compared to the FFC. The results can be used for the design of marathon running shoes, because changing the full carbon fiber plate to segment carbon fiber plate induced some biomechanical transformation but did not significantly affect the running performance, what is more, reducing the peak pressure of the carbon plate to the midsole by cutting the forefoot area of the carbon fiber plate could be beneficial from a long-distance running perspective for manufacturers.

Biomechanical analysis of two runners who developed leg injuries during a six-week transition to maximal running shoes: A case series.

Achilles tendinopathy (AT) and medial tibial stress syndrome (MTSS) are two of the most common running-related injuries. In a previous study investigating running biomechanics before and after a six-week transition to maximal running shoes, two runners dropped out of this study due to Achilles pain and shin pain, respectively. The purpose of this case series was to investigate running biomechanics in those two runners, identifying potential causes for injury in relation to maximal shoe use. Running biomechanics were collected in a laboratory setting for these two runners wearing both a maximal running shoe and traditional running shoe before the six-week transition using an 8-camera motion capture system and two embedded force plates. Both runners displayed prolonged eversion in the maximal shoe, which has been previously cited as a potential risk factor for developing Achilles tendinopathy and medial tibial stress syndrome. Relatively high loading rates and impact forces were also observed in the runner with shin pain in the maximal shoe, which may have contributed to their pain. More prospective research on injury rates in individuals running in maximal shoes is needed.

Footwear designed to enhance energy return improves running economy compared to a minimalist footwear: does it matter for running performance?

The present study compared the effects of a footwear designed to enhance energy return (thermoplastic polyurethane, TPU) vs minimalist shoes on running economy (RE) and endurance performance. In this counterbalanced and crossover design study, 11 recreational male runners performed two submaximal constant-speed running tests and two 3-km time-trials with the two shoe models. Oxygen uptake was measured during submaximal constant-speed running tests in order to determine the RE at 12 km/h and oxygen cost of running (CTO2) at individual average speed sustained during the 3-km running time-trials wearing either of the two shoes. Our results revealed that RE was improved (2.4%) with TPU shoes compared with minimalist shoes (P=0.01). However, there was no significant difference for CTO2 (P=0.61) and running performance (P=0.52) comparing the TPU (710±60 s) and the minimalist (718±63 s) shoe models. These novel findings demonstrate that shoes with enhanced mechanical energy return (i.e. TPU) produced a lower energy cost of running at low (i.e., 12 km/h) but not at high speeds (i.e., average speed sustained during the 3-km running time-trial, ∼15 km/h), ultimately resulting in similar running performance compared to the minimalist shoe.

Can the "Appropriate" Footwear Prevent Injury in Leisure-Time Running? Evidence Versus Beliefs.

Leisure-time running is one of the most popular forms of physical activity around the world. It can be practiced almost everywhere and requires mainly a pair of "appropriate" running shoes. However, the term appropriate is ambiguous, and the properties of running footwear have always generated hot debates among clinicians, coaches, and athletes, whatever the level of practice. As the main interface between the runner's foot and the ground, the shoe potentially plays an important role in managing repetitive external mechanical loads applied to the musculoskeletal system and, thus, in injury prevention. Consequently, over the last decades, running shoes have been prescribed based on matching shoe features to foot morphology. This strategy aligns with the popular belief that footwear is one of the main extrinsic factors influencing running-related injury risk. Despite a seemingly sound strategy for shoe prescription and constant progress in running-footwear technology, the injury rate remains high. Therefore, our aim in this narrative literature review is to clarify whether the prescription of appropriate footwear to prevent injury in running is evidence based, the result of logical fallacy, or just a myth. The literature presented in this review is based on a nonsystematic search of the MEDLINE database and focuses on work investigating the effect of shoe features on injury risk in runners. In addition, key elements for a proper understanding of the literature on running footwear and injury risk are addressed. In this literature review, we outline (1) the main risk factors and the mechanisms underlying the occurrence of running-related injury, (2) important methodologic considerations for generating high-level evidence, (3) the evidence regarding the influence of running-shoe features on injury risk, (4) future directions for research, and (5) final general recommendations.

Standardized Lab Shoes Do Not Decrease Loading Rate Variability in Recreational Runners.

Studies of running mechanics often use a standardized lab shoe, ostensibly to reduce variance between subjects; however, this may induce unnatural running mechanics. The purpose of this study was to compare the step rate, vertical average loading rate, and ground contact time when running in standardized lab shoes versus participants' normal running shoes. Ground reaction forces were measured while the participants ran overground in both shoe conditions at a self-selected speed. The Student's t-test revealed that the vertical average loading rate magnitude was smaller in lab shoes versus normal shoes (42.09 [11.08] vs 47.35 [10.81] body weight/s, P = .013), while the step rate (170.92 [9.43] vs 168.98 [9.63] steps/min, P = .053) and ground contact time were similar (253 [25] vs 251 [20] ms, P = .5227) and the variance of all outcomes was similar in lab shoes versus normal shoes. Our results indicate that using standardized lab shoes during testing may underestimate the loads runners actually experience during their typical mileage.