Effects Of Footwear Research Articles

Effect of increased bending stiffness on running economy and joint biomechanics in uphill running and running on unstable terrain: is there any evidence for embedding carbon plate in trail running footwear?

The emergence of carbon-plated trail running footwear has spurred a re-evaluation of their effects on metabolic power and joint biomechanics. This study investigates the influence of increased longitudinal bending stiffness (LBS) on these parameters during uphill running and on irregular terrain. Ten amateur trail runners wore two conditions of footwear: with and without carbon plates. For each condition, metabolic power was assessed on level and uphill treadmill running (11.6 ± 1.2 km/h and 7.8 ± 0.6 km/h, respectively), while 3D kinematics and kinetics of lower limb joints were evaluated in a laboratory setting on unstable terrain. Subjective assessment of plantar feedback during running on irregular terrain was collected. Regarding biomechanics, discrete variables were extracted as surrogates for joint control on unstable terrains (e.g. normalised jerks, frontal peak angles, and ranges of motion). Because there is no consensus on the quantification of joint stability, the biomechanical analysis was completed with Bayesian statistical parametric mapping to depict differences in-between shoe conditions over the entire signals. Results revealed no footwear effect on metabolic power on level terrain but showed an increase in uphill running metabolic power with the plated condition (2 ± 2%, p = .04). No differences were observed in biomechanical parameters or plantar feedback between conditions. These findings suggest that while increasing LBS does not affect metabolic power during level running, it leads to performance degradation during uphill running. Therefore, the benefits of increased LBS may not be applicable to technical trail running scenarios where running paces are very low. Embedding carbon plates in trail running footwear may lack physiological or biomechanical advantage, underscoring the necessity of considering contextual factors in footwear design for specific activities.

Unlocking the multidimensionality of plantar pressure measurements for the evaluation of footwear in people with diabetes.

The offloading effectiveness of custom-made footwear for people with diabetes is assessed using plantar pressure measurements. While such pressure data is multidimensional, it is mostly analyzed using a scalar - maximum peak plantar pressure (PMax). We aimed to investigate the associations between multiple peak plantar pressure parameters for footwear assessment and determine whether this assessment depends on the chosen parameter. In-shoe plantar pressure was measured in 77 participants with diabetes, peripheral neuropathy, and a recent ulcer or amputation history, while walking in their own custom-made footwear. Six peak plantar pressure parameters were extracted, both scalar (i.e. Pmax, time integral and gradient) and multidimensional (i.e. time curve, map and time map). Footwear was ranked from highest to lowest outcome for each parameter and associations with Pmax were compared using Spearman's rank correlation coefficient. A footwear comparison within subjects using Fleiss' Kappa analysis determined the agreement between parameters using two pairs of footwear of each participant. The rank correlation coefficient was moderate to strong between PMax and the other scalar parameters (ρ=0.46-0.70), and negligible to weak between PMax and the multidimensional parameters (ρ=0.03-0.25). Percentage agreement between parameters for the within-subject footwear comparison was poor (47.5%, κ=0.0652). We conclude that the association and agreement between in-shoe peak pressure parameters is low and the assessment of offloading effectiveness depends on the chosen parameter. This is the first step in unlocking the potential of a multidimensional approach in plantar pressure analysis, possibly changing how we evaluate footwear offloading effectiveness.

Effect of Foot Orthoses and Footwear in People with Rheumatoid Arthritis: An Updated Systematic Review.

Rheumatoid arthritis is a chronic, systemic, inflammatory disease of an autoimmune nature that causes pain and disability in affected patients. Foot pain has become a challenge due to its negative impact on physical function. The objective of this updated systematic review is to describe the effect of foot orthoses and/or footwear in patients with rheumatoid arthritis and foot problems. Scopus, PubMed, CINALH, WOS, and Dialnet were searched for all articles published from January 2013 to September 2024. Inclusion criteria included randomised clinical trials and crossover trials (level of evidence I), published within the last 10 years, involving adults with a diagnosis of rheumatoid arthritis, with no restrictions on gender, race, or ethnicity. All studies that addressed the use of foot orthoses and/or shoe therapy in any type of comparison between these interventions were considered relevant. Review Manager was used to carry out the bias analysis of the selected studies. The reporting was based on the new PRISMA guidelines. A total of 9 relevant articles were selected from an initial sample of 438. These articles analyse and compare the effectiveness of various types of foot orthoses in reducing pain, functional limitation, and disability, as well as improving balance and kinetic and kinematic parameters affected by rheumatoid arthritis. Foot orthoses reduce pain and disability in rheumatoid arthritis, improving balance and kinematic parameters. However, no significant improvements in the patients' functionality and walking ability have been demonstrated. Customised ones with good arch control, heel reinforcement, and metatarsal pad are more effective. No results on the impact of footwear on patients with rheumatoid arthritis have been found in the last 10 years. This systematic review was registered in PROSPERO (CRD42023405645).

The effects of minimal shoes in combination with textured and supportive insoles on spatiotemporal walking gait parameters in healthy young adults

Spatiotemporal parameters, such as speed, cadence, stride length are often adjusted to enhance stability during walking. Minimal shoes and insoles are known to impact dynamic stability, however their combined effect on such gait parameters in healthy young adults remains unexplored. This cross-sectional study assessed the effects of a minimal shoes, the combination of a minimal shoes with a textured insoles, a minimal shoes with a supportive insoles, barefoot walking and habitual shoes on stability-related spatiotemporal walking gait parameters. Sixty-two healthy young adults (41 males and 21 females, age: 24.6 ± 5.5 years, height: 1.73 ± 0.01 m, weight: 73.8 ± 14.2 kg) were assessed using a 2-minute walk test (2-MWT), and a Timed up and Go (TUG) test in a randomized order of five different footwear conditions. Measurements were made using Kinesis GaitTM and QTUGTM sensors. Repeated measures analyses of covariance were conducted to examine the effect of footwear with gender and BMI as covariates. Results revealed improvement in observed gait parameters during the 2-MWT in minimal shoes, minimal shoes with a textured insoles and minimal shoes with a supportive insoles compared to barefoot and habitual footwear. Participants covered a significantly greater distance (p < 0.05) during the 2-MWT at a self-selected speed in all three minimal shoes conditions with larger stride length and improved cadence. Significant variations (p < 0.05) were found between barefoot walking and minimal shoes conditions while participants being least stable during the barefoot walking. The use of textured or supportive insoles within the minimal shoes did not provide any additional benefits nor did it have any detrimental effect on the spatiotemporal parameters. Nevertheless, minimal shoes with or without insoles have the potential to enhance stability during walking as speed, cadence, and stride length are improved.

Performance Effects Of Footwear And Bar Type During The Deadlift

Performance Effects Of Footwear And Bar Type During The Deadlift

The Effect of Footwear on Balance and Stability among Older Adults.

The Effect of Footwear on Balance and Stability among Older Adults.

Identifying the Number of Steps Required for Familiarisation to Athletic Footwear in Healthy Older Adults

Introduction: Research on athletic footwear familiarisation within an older population is sparse. This is problematic because unfamiliar footwear may act as a new perturbation and modify older adults’ walking gait and stability. In addition, while athletic footwear has been suggested to enhance older adults’ comfort and support during activities of daily living, the necessary period for familiarisation with athletic footwear is unknown. Therefore, this study aimed to identify the number of steps required for older adults to be familiarised with athletic footwear of different midsole thicknesses. Methods: Twenty-six healthy and physically active community-dwelling older adults, 21 females (71.1 ± 4.5 years; 164.5 ± 5.3 cm; 68.4 ± 11.4 kg) and five males (70.6 ± 2.3 years; 175.2 ± 7.8 cm; 72.8 ± 9.7 kg), completed a walking-based protocol. Participants walked two trials of 200 steps at their habitual speed on a 10-m track of an optical measurement system in three footwear conditions: (1) New Balance® REVlite 890v6 (thick midsole); (2) New Balance® REVlite 1400v5 (moderate midsole); and (3) New Balance® Minimus 20v7 (thin midsole). Gait speed (m.s-1) and walking time (min) were analysed for each participant over the 400 steps. Number of required familiarisation steps were established over three analysis phases, consisting of steady-state gait assessment, averaging and analysis of blocks of 40 steps, and sequentially comparing these steps with a predetermined threshold. Footwear familiarisation was assumed when the mean gait speed fell within an acceptable level (±2 SD from 320 to 360 step values) and subsequently maintained. Results: Most participants were familiarised with all three footwear conditions (thick n = 18; moderate and thin n = 20) after walking 80 steps. For all participants, the moderate midsole had the shortest familiarisation period (160 steps). The highest number of familiarisation steps was found in the thick (320 steps) and thin midsoles (240 steps) for some participants. Conclusion: A minimum of 320 familiarisation steps is recommended to account for both individual differences and midsole thicknesses. Implementing this walking-based footwear familiarisation protocol would improve validity of future studies, ensuring they analyse footwear effects rather than familiarisation with the footwear.

Effectiveness of footwear and foot orthoses in reducing medial metatarsophalangeal joint pressure in women with hallux valgus

BackgroundHallux valgus is a common condition where the subluxation of the first metatarsophalangeal joint and lateral deviation of the hallux at the interphalangeal joint creates difficulty with footwear fit. Footwear and foot orthoses are commonly prescribed nonsurgical treatments for hallux valgus. Research questionDo extra-width footwear and foot orthoses influence peak pressure at the medial aspect of the metatarsophalangeal and interphalangeal joints in women with hallux valgus? MethodsCommunity-dwelling women with symptomatic hallux valgus underwent gait testing when wearing their own shoes and when wearing extra-width footwear fitted with three-quarter length, arch-contouring prefabricated foot orthoses. Peak pressure (kPa) on the medial aspect of the metatarsophalangeal and medial interphalangeal joints and on the plantar surface of the foot (hallux, lesser toes, metatarsophalangeal joint 1, metatarsophalangeal joints 2–5, midfoot and heel) were measured using the novel pedar®-X system with the pedar® pad and pedar® insole, respectively (Novel, GmbH, Munich, Germany). Paired samples t-tests were used to calculate the differences between the two conditions, and the magnitude of observed differences was calculated using Cohen’s d. ResultsWe tested 28 participants (aged 44–80 years, mean 60.7, standard deviation 10.7). Compared to their own footwear, wearing the intervention footwear and orthoses was associated with a statistically significant decrease in pressure on the medial aspect of the metatarsophalangeal joint (58.3 ± 32.8 versus 42.6 ± 32.8, p=0.026, d=0.49), increased pressure under the midfoot (70.7 ± 25.7 versus 78.7 ± 23.6, p=0.029, d=0.33) and decreased pressure underneath the heel (137.3 ± 39.0 versus 121.3 ± 34.8, p=0.019, d=0.45). SignificanceThe intervention footwear and orthoses significantly decreased peak pressure on the medial aspect of the first metatarsophalangeal joint but had no significant effect on the interphalangeal joint. Further studies are required to determine whether these changes are associated with improvements in symptoms associated with hallux valgus.

An exploration of footwear preferences, attitudes and beliefs in people with knee osteoarthritis: A qualitative study

BackgroundAlthough footwear can improve pain and function in individuals with knee osteoarthritis (OA), perspectives about footwear in this population have not been explored. ObjectivesThis qualitative study explored preferences, attitudes and beliefs about footwear in adults with knee OA. MethodsTwenty individuals with a clinical diagnosis of knee OA (aged 45–79 years, 65% women) participated in semi-structured interviews about factors which influence footwear selection, the effect of footwear on knee symptoms, and footwear modifications. Data were analysed thematically. ResultsFour themes, with sub-themes, were identified: i) there are specific footwear characteristics people look for, with comfort as their top priority; ii) shoe appearance is important; iii) footwear can aggravate or ease symptoms; and iv) people with knee OA find footwear in a variety of ways. Participants related built-in arch support, a cushioned insole and low/no heel, without addition of foot orthoses, to comfort, and were willing to pay more for comfort and quality. Appearance was also a consideration, and participants indicated they would tolerate short periods of symptom aggravation for aesthetic shoes. Participants felt that footwear choice affected their knee symptoms and risk of slipping/twisting. Participants reported that their footwear choices were determined through trial-and-error, and sometimes on advice from health professionals or shoe store salespersons. ConclusionsThere are specific footwear features important to individuals with knee OA. Knowledge of these features can be used by health professionals to inform footwear discussions with knee OA patients and serve as considerations when developing footwear targeted for this population.

Advancing our ability to quantify an individual’s habitual motion path and deviation when running

The habitual motion path theory states that exhibiting kinematic differences between running and habitual movement tasks may increase the risk of running-related injury. Staying near one’s habitual motion path when running has been shown to reduce compression of the knee joint cartilage, a proxy for decreased soft tissue loading. Previous efforts to quantify one’s habitual motion path and deviation when running have utilised just one habitual movement and one time point during the stance phase of running. The methodology advancement described in this manuscript focused on advancing habitual motion path theory research by (1) increasing the number of movements for quantifying an individual’s habitual motion path; and (2) utilising the entire stance phase when running to quantify deviations as opposed to one time point. We liken the advancements in the method described in this manuscript as with the first method we were using a ruler to assess one’s habitual motion path and deviations, and now we are using calipers; providing a more accurate understanding of an individual’s unique habitual movement and deviation when running. We also discuss future potential research avenues related to understanding running biomechanics and footwear effects that this tool will allow us to explore.

Informing wobble-board training and assessment through an investigation of the effect of biological-sex, anthropometrics, footwear and dual-tasking in young adults.

Despite wobble board use being common in physiotherapy the effect of certain factors, essential to clinical reasoning, have not been investigated. To determine the effect of biological sex, anthropometrics, footwear and dual tasking (DT) on wobble board balance performance. Eighty-six healthy participants (44 females) had their wobble board performance measured during double-leg-stance (DLS) with eyes open (DLSEO), closed (DLSEC) and single-leg-stance (SLS) tasks, with and without footwear and a DT added. Anthropometrics were also measured. Females outperformed males during most tasks, with some large effect sizes (ES). Performance was moderately related to weight and shoulder, waist and hip circumference. Overall, there were no differences between footwear and no footwear, except for males during SLS. DT made little difference, except during DLSEO and SLS, where single task was better than DT, though only females had a large ES. During wobble board tasks, biological sex differences were observed and a modest correlation between anthropometrics and performance noted. DT and footwear had minimal effect.

The Influence of "Super-Shoes" and Foot Strike Pattern on Metabolic Cost and Joint Mechanics in Competitive Female Runners.

The objective of this study is to assess the influence of "super-shoes" on metabolic cost and joint mechanics in competitive female runners and to understand how foot strike pattern may influence the footwear effects. Eighteen competitive female runners ran four 5-min bouts on a force instrumented treadmill at 12.9 km·h -1 in 1) Nike Vaporfly Next% 2™ (SUPER) and 2) Nike Pegasus 38™ (CON) in a randomized and mirrored order. Metabolic power was improved by 4.2% ( P < 0.001; d = 0.43) and metatarsophalangeal (MTP) negative work ( P < 0.001; d = 1.22), ankle negative work ( P = 0.001; d = 0.67), and ankle positive work ( P < 0.001; d = 0.97) were all smaller when running in SUPER compared with CON. There was no correlation between foot strike pattern and the between-shoe (CON to SUPER) percentage change for metabolic power ( r = 0.093, P = 0.715). Metabolic power improved by 4.2% in "super-shoes" (but only by ~3.2% if controlling for shoe mass differences) in this cohort of competitive female runners, which is a smaller improvement than previously observed in men. The reduced mechanical demand at the MTP and ankle in "super-shoes" are consistent with previous literature and may explain or contribute to the metabolic improvements observed in "super-shoes"; however, foot strike pattern was not a moderating factor for the metabolic improvements of "super-shoes." Future studies should directly compare the metabolic response among different types of "super-shoes" between men and women.

Assessing the effects of foot strike patterns and shoe types on the control of leg length and orientation in running

This research investigates the stabilization of leg length and orientation during the landing phase of running, examining the effects of different footwear and foot strike patterns. Analyzing kinematic data from twenty male long-distance runners, both rearfoot and forefoot strikers, we utilized the Uncontrolled Manifold approach to assess stability. Findings reveal that both leg length and orientation are indeed stabilized during landing, challenging the hypothesis that rearfoot strikers exhibit less variance in deviations than forefoot strikers, and that increased footwear assistance would reduce these deviations. Surprisingly, footwear with a lower minimalist index enhanced post-landing stability, suggesting that cushioning contributes to both force dissipation and leg length stability. The study indicates that both foot strike patterns are capable of effectively reducing task-relevant variance, with no inherent restriction on flexibility for rearfoot strikers. However, there is an indication of potential reliance on footwear for stability. These insights advance our understanding of the biomechanics of running, highlighting the role of footwear in stabilizing leg length and orientation, which has significant implications for running efficiency and injury prevention.

Impact of High-Heeled Footwear on the health of the young female students of selected colleges of Mangalore, India

Introduction: High-heeled shoes are a leading cause of foot problems and chronic lower limbs, as well as discomfort, fatigue, and an increased risk of injury. The research aimed to analyze the influence of wearing high-heeled shoes on the foot health of young females. The study emphasizes the need to create awareness among females about the detrimental impacts of utilizing heeled footwear over the long term on discomfort, BMI, and functional capacity. A slight change in footwear choices could significantly reduce discomfort and disability experiences. Methods: Purposive sampling was used to select 50 young female students studying in Mangalore's undergraduate college for the cross-sectional study. A pre-designed and pre-tested structured Google Form questionnaire was used to examine the socio-demographic characteristics and outcome measures, including the location of pain, the intensity of the pain, and functional ability. Data was collected in the second half of 2020. Descriptive and inferential statistics were used to analyze the data. Results: According to the survey, 46% of young female students exhibited poor functional activities while wearing high heels. It was found that 12% of students had pain in their toes all of the time, 8% had pain in the arch of their foot, and 25% had discomfort in their lower back occasionally. About two-thirds (64%) felt averagely manageable discomfort. Conclusion: The study found that wearing heeled shoes has a significant influence on women's musculoskeletal systems. Young females will be better able to resist pain from the deforming effects of footwear if they condition their feet properly and choose the appropriate footwear.

Individualization of Footwear for Optimizing Running Economy: A Theoretical Framework.

Advanced footwear technologies contain thicker, lightweight, and more resilient midsoles and are associated with improved running economy (RE) compared with traditional footwear. This effect is highly variable with some individuals gaining a greater RE benefit, indicating that biomechanics plays a mediating role with respect to the total effect. Indeed, the energy generated by contractile elements and the elastic energy recovered from stretched tendons and ligaments in the legs and feet are likely to change with footwear. Therefore, if RE is to be maximized according to individual characteristics, an individualized approach to footwear selection is required. However, current theoretical frameworks hinder this approach. Here, we introduce a framework that describes causal relationships between footwear properties, biomechanics, and RE. The framework proposes that RE changes with footwear due to (1) a direct effect of footwear properties-for example, increased or decreased energy return-and (2) a mediating effect of footwear on ankle and foot biomechanics and the spring-mass system. By describing the total effect as 2 complementary pathways, the framework facilitates research that aims to separately quantify direct and mediating effects of footwear. This may permit the development of footwear materials that can separately target the direct and individual mediating effects.

Footwear, Orthoses, and Insoles and Their Effects on Balance in Older Adults: A Scoping Review.

Footwear, orthoses, and insoles have been shown to influence balance in older adults; however, it remains unclear which features, singular or in combination, are considered optimal. The aim of this scoping review was to identify and synthesise the current evidence regarding how footwear, orthoses, and insoles influence balance in older adults. Four electronic databases (MEDLINE, CINAHL, Embase, and AMED) were searched from inception to October 2023. Key terms such as "shoe*," "orthoses," "postural balance" and "older people" were employed in the search strategy. Studies meeting the following criteria were included: (i) participants had a minimum age ≥60 years, and were free of any neurological, musculoskeletal, and cardiovascular diseases; (ii) an active intervention consisting of footwear, foot orthoses, or insoles was evaluated; and (iii) at least one objective outcome measure of balance was reported. A total of 56 studies from 17 different countries were included. Three study designs were utilised (cross-sectional study, n = 44; randomised parallel group, n = 6; cohort study n = 6). The duration of studies varied considerably, with 41 studies evaluating immediate effects, 14 evaluating effects from 3 days to 12 weeks, and 1 study having a duration of 6 months. Seventeen different interventions were evaluated, including/consisting of textured insoles (n = 12), heel elevation (n = 8), non-specific standardised footwear and changes in sole thickness or hardness (n = 7 each), sole geometry or rocker soles, contoured or custom insoles and high collar height (n = 6 each), insole thickness or hardness and vibrating insoles (n = 5 each), outsole tread (n = 4), minimalist footwear and slippers (n = 3 each), balance-enhancing shoes, footwear fit, socks, and ankle-foot orthoses (n = 2 each), and eversion insoles, heel cups, and unstable footwear (n = 1 each). Twenty-three different outcomes were assessed, and postural sway was the most common (n = 20), followed by temporo-spatial gait parameters (n = 17). There was uncertainty regarding intervention effectiveness. Overall, features such as secure fixation, a textured insole, a medium-to-hard density midsole and a higher ankle collar, in isolation, were able to positively impact balance. Conversely, footwear with an elevated heel height and the use of socks and slippers impaired balance. There is a substantial body of literature exploring the effects of footwear, orthoses, and insoles on balance in older adults. However, considerable uncertainty exists regarding the efficacy of these interventions due to variability in methodological approaches. Further high-quality research is necessary to determine whether a singular intervention or a combination of interventions is most effective for enhancing balance in older adults.

Human‐in‐the‐loop optimized rocker profile of running shoes to enhance ankle work and running economy

AbstractIncreasing the efficiency at which muscles generate mechanical power could improve running economy. A potential way to reduce muscle fiber shortening velocities and enhance energy storing of the Triceps Surae is changing their gear ratio at the ankle via optimization of shoe rollover profile. The aim of the current study was to individually optimize rollover profile of rocker shoes via human‐in‐the‐loop optimization to maximize positive ankle work to redistribute joint work from the hip and knee to the ankle and improve running economy. A total of 10 runners ran on a treadmill with experimental rocker shoes in which apex position and angle were optimized using an evolution algorithm to maximize positive ankle work. We compared experimental shoes with optimal settings, standard settings, and control shoes in terms of biomechanics and running economy. Optimal apex parameters differed considerably between participants. The optimal condition resulted in higher positive ankle work and a higher proportional share of the ankle in the total positive lower limb work compared to the standard condition. A difference in running economy between these conditions was not found. Human‐in‐the‐loop optimization can redistribute joint work from the hip and knee to the ankle by individually optimizing apex parameters. Although this did not improve running economy, the study showed that human‐in‐the‐loop optimization could improve the effectiveness of footwear with respect to the selected optimization parameter on an individual level.

Investigation of the relationship between plantar pressure and calf muscle tone. development and testing of the new test bench

Plantar pressure is the most important biomechanical parameter for evaluating and modeling postoperative treatment conditions for patients with deformity of the first ray of the foot. Modern foot surgery involves early activation of the patient after surgery. The universality and reliability of this approach after surgical correction of valgus deformity of the first toe is questionable. In this regard, studies are being conducted to determine the quantitative parameters of plantar pressure under normal conditions and with the use of postoperative footwear used to reduce it in the forefoot. The relationship between calf muscle tone and plantar pressure in the forefoot has been established. There have been no studies determining the influence of calf muscle tone on the effectiveness of unloading the forefoot using postoperative footwear. The plantar pressure has been studied experimentally, including the influence of the calf muscle tone. An experimental stand was developed and tested: it was used to study the distribution of pressure under the foot in 26 healthy individuals in the standing position on a platform and in postoperative shoes. Quantitative assessment of the tone of the calf muscle in the same subjects was carried out. The plantar pressure in subjects wearing postoperative shoes and the amplitude of dorsal flexion of the ankle joint with the knee joint straightened and flexed at 90 degrees were compared. The mean load reduction in postoperative shoes was 57 %, median 60 %. Measurement of calf muscle tone (extensibility) can be used to predict whether forefoot loading will be reduced with the use of special shoes. The dorsiflexion angle of the foot should be used as a criterion: if it is greater than 10 degrees, there is a high probability that forefoot loading will be reduced. For dorsiflexion measured at the straightened knee joint, the probability of predicting the effectiveness of postoperative footwear is 79 %. A similar probability when using the amplitude of dorsiflexion of the foot measured with the knee joint flexed at 90 degrees as a prediction criterion was 66 %.

Influence of Footwear Selection on Youth Running Biomechanics: A Pilot Study.

The relationship of running biomechanics, footwear, and injury has been studied extensively in adults. There has been little research on the effects of footwear on running biomechanics in youth. Running biomechanics of youth will be significantly affected by changes in footwear. Minimal shoe running will demonstrate similarities to barefoot. Crossover study design: randomized trial. Level 2. A total of 14 active male youth (8-12 years old) participants with no previous exposure to minimalist shoes or barefoot running had running biomechanics (lower extremity sagittal plane kinematics and vertical ground reaction forces [vGRFs]) collected and analyzed in 3 footwear conditions (barefoot, traditional, and minimal shoe). The average vertical loading rate (AVLR) was significantly greater running barefoot (173.86 bodyweights per second [BW/s]) and in the minimal shoe (138.71 BW/s) compared with the traditional shoe (78.06 BW/s), (P < 0.01). There were significant differences between shoe conditions for knee flexion at initial contact (P < 0.01), knee sagittal plane excursion (P < 0.01), peak dorsiflexion (P < 0.01), and dorsiflexion at initial contact (P = 0.03). No participants displayed a forefoot-strike during this study. The introduction of barefoot and minimalist running in habitually shod youth significantly affected the running biomechanics of youth and caused immediate alterations in both lower extremity kinematics and vGRFs. Running barefoot or in minimal shoes dramatically increased the AVLR, which has been associated with injury, compared with a traditional shoe. This study evaluated the effects of footwear on overground running biomechanics, including AVLR, in pre- and early-adolescent youth males. Based on our findings, clinicians should exercise caution in barefoot or minimal shoe transition among young, habitually shod, runners due to the immediate and dramatic increases in AVLRs.

Influence of the World Athletics Stack Height Regulation on Track Running Performance.

Ruiz-Alias, SA, Pérez-Castilla, A, Soto-Hermoso, VM, and García-Pinillos, F. Influence of the world athletics stack height regulation on track running performance. J Strength Cond Res 37(11): 2260-2266, 2023-A new footwear regulation based on limiting the stack height (i.e., amount of material between the feet and the ground) has been established by World Athletics to ensure that performance is achieved through the primacy of human effort over technology in running shoes. Analyzing the effect of legal and illegal shoes on running performance is therefore needed to determine its effectiveness. Thus, this study aimed (a) to compare the effect of 2 footwear models categorized as legal and illegal by the World Athletics regulation on track running performance and (b) to analyze the derived metrics of the athletes' biomechanics when using each footwear model at racing paces. Within 1 week, 14 highly trained athletes performed 2 testing sessions composed of 2 time trials of 9- and 3-minute duration with 30 minutes of recovery between them. The athletes wore the "Nike ZoomX Dragonfly" track spikes model and the "Nike ZoomX Vaporfly Next % 2" marathon shoe model in a counterbalanced randomized order. The results revealed that (a) there was only a small worthwhile improvement in the 3-minute time trial when using the marathon shoes of 0.97% (-0.04 to 1.98%) and (b) there was a main effect of footwear in 7 of the 9 biomechanical variables analyzed (p ≤ 0.050). The ground contact time was the unique performance predictor (p = 0.005, adjusted R2 = 0.476). Altogether, the use of legal and illegal running shoes altered the runners form, which only influenced the mid-distance performance.