Foot posture alteration and recovery following a full marathon run

Adaptive Changes in Longitudinal Arch During Long-distance Running

This study investigates the biomechanical adaptations of the longitudinal arch (LA) in long-distance runners, focusing on changes in stiffness, angle, and moment during a 60-minute run. Twenty runners participated in this experiment, and were asked to run at a speed of 2.7 m·s-1 for 60 minutes. The kinematic and kinetic data collected at five-minute intervals during running were calculated, including the stiffness of LA in the loading phase (k load ) and the stiffness of LA in the unloading phase (k unload ), the maximum LA moment (M max ), the range of LA angle change (∆θ range ), and the maximum LA angle change (∆θ max ). Foot morphology was also scanned before and after running. Variations of kinematic and kinetic data were analyzed throughout the running activity, as well as variations of foot morphology pre- and post-run. Results showed that there was a significant decrease in k load (p<0.001), coupled with increases in ∆θ range (p=0.002) and ∆θ max (p<0.001), during the first 15 minutes of running, which was followed by a period of mechanical stability. No differences were found in k unload and M max throughout the running process and the foot morphology remained unchanged after running. These results highlight a critical adaptation phase that may be pivotal for improving running economy and performance.

A Short-Term Evaluation of Foot Pronation Tendency in Healthy Recreational Runners

Running is a highly physical activity, and it is related to injuries when there is an excessive pronation of the foot. This study evaluates, from a sample group of healthy recreational runners, if the foot tends to pronate after a period of running activity and when, with respect to a period of running compared to walking, evaluated during several phases: after 30, 45, and 60 min. This quasi-experimental study has been carried out on a total of 36 healthy recreational subjects. The subjects were evaluated during two different activities: running activity for a period of an hour with respect to normal walking activity. The main outcome measures were the foot posture index (FPI) and the navicular drop test (NDT), which were evaluated at p1 (the screening day), after 30 min of activity (p2), after 45 min of activity (p3), and finally after 60 min (p4) during running or walking activity. The analysis showed significant differences for the FPI and NDT variables in both groups and on both feet, comparing p1 and p4. These changes showed a significant relationship comparing p1 and p3 for the FPI variable, and for the NDT variable (p < 0.001) of the left foot and, with respect to the right foot, significance was shown to the FPI comparing the p1 and p2. A significant difference was found in the tendency to pronate the foot after a period of running compared to the same period of walking after 60 min of activity. Running produced an excessive pronation of the foot after 45 min of activity, evaluated with the FPI for both feet.

Influence of Body Mass on Running-Induced Changes in Mechanical Properties of Plantar Fascia

ABSTRACT

Shiotani, H, Mizokuchi, T, Yamashita, R, Naito, M, and Kawakami, Y. Influence of body mass on running-induced changes in mechanical properties of plantar fascia. J Strength Cond Res 37(11): e588-e592, 2023-Body mass is a major risk factor for plantar fasciopathy; however, evidence explaining the process between risk factors and injury development is limited. Long-distance running induces transient and site-specific reduction in plantar fascia (PF) stiffness, reflecting mechanical fatigue and microscopic damage within the tissue. As greater mechanical loads can induce greater reduction in tissue stiffness, we hypothesized that the degree of running-induced change in PF stiffness is associated with body mass. Ten long-distance male runners (age: 21 - 23 years, body mass: 55.5 ± 4.2 kg; mean ± SD ) and 10 untrained men (age: 20 - 24 years, body mass: 58.4 ± 5.6 kg) ran for 10 km. Before and immediately after running, the shear wave velocity (SWV) of PF at the proximal site, which is an index of tissue stiffness, was measured using ultrasound shear wave elastography. Although the PF SWV significantly decreased after running in runners (-4.0%, p = 0.010) and untrained men (-21.9%, p < 0.001), runners exhibited smaller changes ( p < 0.001). The relative changes in SWV significantly correlated with body mass in both runners ( r = -0.691, p = 0.027) and untrained individuals ( r = -0.723, p = 0.018). These results indicate that a larger body mass is associated with a greater reduction in PF stiffness. Our findings provide in vivo evidence of the biomechanical basis for body mass as a risk factor for plantar fasciopathy. Furthermore, group differences suggest possible factors that reduce the fatigue responses, such as adaptation enhancing the resilience of PF and running mechanics.

Methodological and statistical approaches for the assessment of foot shape using three-dimensional foot scanning: a scoping review

OBJECTIVE

The objectives of this study were to: (i) review and provide a narrative synthesis of three-dimensional (3D) foot surface scanning methodological and statistical analysis protocols, and (ii) develop a set of recommendations for standardising the reporting of 3D foot scanning approaches.

METHODS

A systematic search of the SCOPUS, ProQuest, and Web of Science databases were conducted to identify papers reporting 3D foot scanning protocols and analysis techniques. To be included, studies were required to be published in English, have more than ten participants, and involve the use of static 3D surface scans of the foot. Papers were excluded if they reported two-dimensional footprints only, 3D scans that did not include the medial arch, dynamic scans, or derived foot data from a full body scan.

RESULTS

The search yielded 78 relevant studies from 17 different countries. The available evidence showed a large variation in scanning protocols. The subcategories displaying the most variation included scanner specifications (model, type, accuracy, resolution, capture duration), scanning conditions (markers, weightbearing, number of scans), foot measurements and definitions used, and statistical analysis approaches. A 16-item checklist was developed to improve the consistency of reporting of future 3D scanning studies.

CONCLUSION

3D foot scanning methodological and statistical analysis protocol consistency and reporting has been lacking in the literature to date. Improved reporting of the included subcategories could assist in data pooling and facilitate collaboration between researchers. As a result, larger sample sizes and diversification of population groups could be obtained to vastly improve the quantification of foot shape and inform the development of orthotic and footwear interventions and products.

Toward improved understanding of foot shape, foot posture, and foot biomechanics during running: A narrative review

The current narrative review has explored known associations between foot shape, foot posture, and foot conditions during running. The artificial intelligence was found to be a useful metric of foot posture but was less useful in developing and obese individuals. Care should be taken when using the foot posture index to associate pronation with injury risk, and the Achilles tendon and longitudinal arch angles are required to elucidate the risk. The statistical shape modeling (SSM) may derive learnt information from population-based inference and fill in missing data from personalized information. Bone shapes and tissue morphology have been associated with pathology, gender, age, and height and may develop rapid population-specific foot classifiers. Based on this review, future studies are suggested for 1) tracking the internal multi-segmental foot motion and mapping the biplanar 2D motion to 3D shape motion using the SSM; 2) implementing multivariate machine learning or convolutional neural network to address nonlinear correlations in foot mechanics with shape or posture; 3) standardizing wearable data for rapid prediction of instant mechanics, load accumulation, injury risks and adaptation in foot tissue and bones, and correlation with shapes; 4) analyzing dynamic shape and posture via marker-less and real-time techniques under real-life scenarios for precise evaluation of clinical foot conditions and performance-fit footwear development.

Contemporary Review: The Foot and Ankle in Long-Distance Running

Distance runners represent a unique patient population. The cyclic activity associated with distance running leads to a high incidence of injury. Gait patterns, the extrinsic and intrinsic muscles of the foot and ankle, foot strike pattern, shoe wear considerations, alignment, and orthotics are also all important considerations that must be considered by the treating provider. The purpose of this work is to review relevant functional anatomy, recent studies on gait patterns in running, orthotics, and theory on how the body moves through space during running in order to better equip the clinician to treat long distance runners.

Effect of Long-Distance Running on Inter-segment Foot Kinematics and Ground Reaction Forces: A Preliminary Study

Long-distance running has gained massive popularity in recent years, yet the intra-foot adaptations during this event remain unclear. This study aimed to examine the kinematic and ground reaction force alterations induced within the foot following a 5 and 10 km run using the Oxford Foot Model Ten marathon-experienced recreational runners participated in this study. Five-kilometer running led to more rearfoot dorsiflexion, rearfoot eversion, and rearfoot rotation while less forefoot plantarflexion during the stance phase. Increased rearfoot plantarflexion, while decreased forefoot plantarflexion, supination, adduction, and hallux plantarflexion were observed at 10 km. In addition, the forefoot space of footwear was found to play a role in hallux kinematics. Concerning GRFs, only a lesser propulsive force was presented after a 10 km run. Findings of this study showed that 5 km of running would induce excessive foot motion while 10 km of running may gradually change the foot posture and lead to reduced propulsive forces, which could potentially increase the risks of running-related injuries (RRI) due to overuse or fatigue. Nevertheless, further research is warranted, and this study could be used as a preliminary reference to evaluate and predict foot running-related injuries.

Increase in foot arch asymmetry after full marathon completion

Long-distance running results in lowering of the foot medial longitudinal arch, but it is unknown whether the left and right arches decrease equally. This study aimed to determine whether foot arch asymmetry increases upon completion of a full marathon and to identify factors capable of explaining the degree of asymmetry of navicular height and navicular height displacement. The three-dimensional foot posture data of 74 collegiate runners were obtained using an optical foot scanner system before (PRE) and immediately after (POST) a full marathon. The navicular height and arch height ratio (normalised navicular height by foot length) of both feet significantly decreased from PRE to POST full marathon completion (44.3 ± 6.3 mm versus 40.8 ± 6.5 mm, 17.8 ± 2.5 versus 16.6 ± 2.7, respectively; p < 0.001, both). The asymmetry of the arch height ratio was significantly greater POST than PRE marathon. Multiple linear regression analysis indicated that the POST-race Asymmetry Index (AI) of navicular height was significantly predicted by the PRE-race AI of navicular height; navicular height displacement was predicted by PRE-race navicular height and the marathon time. Full marathon running induced increasing asymmetry and lowering of the medial longitudinal arch in runners.

Acute effects of long-distance running on mechanical and morphological properties of the human plantar fascia

Long‐distance running (LDR) can induce transient lowering of the foot arch, which may be associated with mechanical fatigue of the plantar fascia (PF). However, this has not been experimentally tested in vivo. The purpose of this study was to test our hypothesis that LDR induces transient and site‐specific changes in PF stiffness and morphology and that those changes are related to the lowering of the foot arch. Ten male recreational long‐distance runners and 10 untrained men were requested to run overground for 10 km. Before and after running, shear wave velocity (SWV: an index of soft tissue stiffness) and thickness of PF at three different sites from its proximal to distal end were measured using supersonic shear imaging and B‐mode ultrasonography. Foot dimensions including the navicular height were measured using a three‐dimensional foot scanner. SWV at the proximal site of PF and navicular height was significantly decreased in both groups after running, with a higher degree in untrained men (−21.9% and −14.1%, respectively) than in runners (−4.0% and −6.3%, respectively). The relative change (%Δ) in SWV was positively correlated with %Δnavicular height in both groups (r = .69 and r = .65, respectively). Multiple regression analysis revealed that %ΔSWV at the proximal site solely explained 72.7% of the total variance in %Δnavicular height. It is concluded that LDR induces transient and site‐specific decreases in PF stiffness. These results suggest that the majority of running‐induced lowering of the foot arch is attributable to the reduction of PF stiffness at the proximal site.

Foot Pronation Contributes to Altered Lower Extremity Loading After Long Distance Running

This study presents an investigation of the changes in foot posture, joint kinematics, joint moments and joint contact forces in the lower extremity following a 5 k treadmill run. A relationship between knee and ankle joint loading and foot posture index (FPI) is developed. Twenty recreational male heel-strike runners participated in this study. All participants had a history of running exercise and were free from lower extremity injuries and foot deformities. Foot posture was assessed from a six-item FPI to quantitatively classify high supination to high pronation foot poses. The FPI is scored using a combination of observations and foot palpations. The three-dimensional marker trajectories, ground reaction force and surface electromyography (EMG) were recorded at pre and post-gait sessions conducted over-ground and 5 k running was conducted on a treadmill. Joint kinematics, joint moments and joint contact forces were computed in OpenSim. Simulated EMG activations were compared against experimental EMG to validate the model. A paired sample t-test was conducted using a 1D statistical parametric mapping method computed temporally. Hip joint moments and contact forces increased during initial foot contact following 5 k running. Knee abduction moment and superior-inferior knee contact force increased, whereas the knee extension moment decreased. Ankle plantarflexion moment and ankle contact forces increased during stance. FPI was found to be moderately correlated with peak knee and ankle moments. Recreational male runners presented increased static foot pronation after 5 k treadmill running. These findings suggest that following mid distance running foot pronation may be an early indicator of increased lower limb joint loading. Furthermore, the FPI may be used to quantify the changes in knee and ankle joint moments.