Change in foot strike patterns and performance in recreational runners during a road race: A cross-sectional study

ObjectivesTo characterise foot strike and observe change in foot strike patterns with increasing distance during a 15 km recreational running road race. To assess the impact of foot strike on running performance.DesignObservational cross-sectional study.MethodsFoot strike patterns were determined at the 3 km and 13 km checkpoints for 459 participants during the 2017 Melbourne City to Sea recreational running event. Foot strike patterns were categorised as either rearfoot strike (RFS) or non-rearfoot strike (NRFS) at both checkpoints and analyses were conducted on intra-individual change in foot strike as well as relationship to finishing time.ResultsThe most prevalent foot strike pattern at 3 km and 13 km was RFS with 76.9% (95% CI: 73.2%–80.5%) and 91.0% (95% CI: 88.7%–93.1%) using this pattern, respectively. Of the 105 participants who ran with a NRFS at 3 km, 61% changed to RFS at 13 km. Race completion time differed by foot strike pattern, where mean time for consistent NRFS (62.64 ± 11.20 min) was significantly faster than consistent RFS (72.58 ± 10.84 min; p < 0.001) and those who changed from NRFS to RFS between checkpoints (67.93 ± 10.60 min; p = 0.040).ConclusionsWhile the majority of recreational distance runners RFS within race settings, the fastest runners were those who consistently ran with a NRFS. In runners that use a NRFS early, a large proportion change to RFS as distance increases. Further research is warranted to determine whether interventions aimed at reducing muscular fatigue can attenuate this change and enhance running performance.     

Plantar loading changes with alterations in foot strike patterns during a single session in habitual rear foot strike female runners

ObjectivesCharacterize plantar loading parameters when habitually rear foot strike (RFS) runners change their pattern to a non-rear foot strike (NRFS).DesignExperimental.SettingUniversity biomechanics laboratory.ParticipantsTwenty three healthy female runners (Age: 22.17 ± 1.64 yrs; Height: 168.91 ± 5.46 cm; Mass: 64.29 ± 7.11 kg).Main outcome measuresPlantar loading was measured using an in-sole pressure sensor while running down a 20-m runway restricted to a range of 3.52–3.89 m/s under two conditions, using the runner's typical RFS, and an adapted NRFS pattern. Repeated measures multivariate analysis of variance was performed to detect differences in loading between these two conditions.ResultsForce and pressure variables were greater in the forefoot and phalanx in NRFS and greater in the heel and mid foot in RFS pattern, but the total force imposed upon the whole foot and contact time remained similar between conditions. Total peak pressure was higher and contact area was lower during NRFS running.ConclusionsThe primary finding of this investigation is that there are distinctly different plantar loads when changing from a RFS to NRFS during running. So, during a transition from RFS to a NRFS pattern; a period of acclimation should be considered to allow for adaptations to these novel loads incurred on plantar regions of the foot.     

Spatiotemporal characteristics of habitually shod runners change when performing barefoot running

Introduction

Habitually shod rear-foot strike (RFS) runners demonstrate changes in spatiotemporal variables when running barefoot; however, it is unknown whether these changes are a function of running barefoot and/or adopting different foot-strike patterns. Therefore, the purpose of this study was to examine changes in spatiotemporal variables when habitually shod RFS runners transition to barefoot running.

Methods

Inverse dynamic methodology was used to examine 22 habitually shod RFS runners who performed overground running, shod and barefoot. Runners were grouped according to their novice barefoot foot-strike pattern: RFS, mid-foot strike (MFS) and forefoot strike (FFS). Runners were also grouped to examine differences between shod and barefoot running.

Results

Of the 22 RFS shod runners, 5 adopted a FFS, 9 adopted a MFS, and 8 maintained a RFS during novice barefoot running. We report a significant main effect of running barefoot for spatiotemporal variables, but not for foot-strike pattern. Relative to when shod, all groups of runners took shorter strides and steps. RFS and MFS runners also exhibited higher step frequency and exhibited shorter step and cycle times, while RFS and FFS runners both exhibited shorter stance times. These findings indicate that barefoot running has a significant influence on spatiotemporal measures, regardless of utilized foot-strike pattern.

     

Effect of training volume on footstrike patterns over an exhaustive run

BackgroundAlthough footstrike pattern (FP) may not be a factor influencing running performance, 11–75% of world-class distance runners use a non-rearfoot FP. However, little attention has been paid to describe the effect of running volume on FP changes when a runner is fatigued.Research questionDoes the training volume provide an adequate stimulus to mitigate FP changes during an exhaustive run in non-rearfoot, habitual minimalist footwear runners?MethodsThe objective of this study was to compare FP between non-rearfoot, habitual minimalist footwear runners with a moderate training volume (MT) and a high training volume (HT) during an exhaustive run on a motorized treadmill. Based on their weekly training volume (distance), twenty-eight runners were arranged into two groups paired by height and age. At the first visit, runners underwent a VO2max test to acquire their velocity for the exhaustive run. During the second visit, biomechanical and physiological analysis of the beginning and the end phase of the exhaustive run was done.ResultsThe frontal plane foot angle, the sagittal plane ankle angle at the initial contact (IC), and the foot eversion ROM showed a significant interaction effect (P < 0.05). Additionally, the sagittal plane footstrike angle, the frontal plane foot angle, the sagittal plane ankle angle, knee flexion angle at IC and foot eversion ROM showed a significant effect of fatigue (P < 0.05). Finally, the frontal plane foot angle, the sagittal plane footstrike angle, the sagittal plane ankle angle, and the knee flexion angle showed significant group effects (P < 0.05).SignificanceThe training volume affects the footstrike pattern of non-rearfoot, habitual minimalist footwear runners when they are fatigued. The highly trained runners maintained their ankle angle throughout the exhaustive running protocol, whereas the moderately trained group changed the frontal and sagittal plane characteristics of their footstrike pattern.     

Is the foot striking pattern more important than barefoot or shod conditions in running?

People have advocated barefoot running, claiming that it is better suited to human nature. Humans usually run barefoot using a forefoot strike and run shod using a heel strike. The striking pattern was thought to be a key factor that contributes to the benefit of barefoot running. The purpose of this study is to use scientific data to prove that the striking pattern is more important than barefoot or shod conditions for runners on running injuries prevention. Twelve habitually male shod runners were recruited to run under four varying conditions: barefoot running with a forefoot strike, barefoot running with a heel strike, shod running with a forefoot strike, and shod running with a heel strike. Kinetic and kinematic data and electromyography signals were recorded during the experiments. The results showed that the lower extremity can gain more compliance when running with a forefoot strike. Habitually shod runners can gain more shock absorption by changing the striking pattern to a forefoot strike when running with shoes and barefoot conditions. Habitually shod runners may be subject to injuries more easily when they run barefoot while maintaining their heel strike pattern. Higher muscle activity in the gastrocnemius was observed when running with a forefoot strike, which may imply a greater training load on the muscle and a tendency for injury.     

Effects of the foot strike pattern on muscle activity and neuromuscular fatigue in downhill trail running

Minimizing musculo‐skeletal damage and fatigue is considered paramount for performance in trail running. Our purposes were to investigate the effects of the foot strike pattern and its variability on (a) muscle activity during a downhill trail run and (b) immediate and delayed neuromuscular fatigue. Twenty‐three runners performed a 6.5‐km run (1264 m of negative elevation change). Electromyographic activity of lower‐limb muscles was recorded continuously. Heel and metatarsal accelerations were recorded to identify the running technique. Peripheral and central fatigue was assessed in knee extensors (KE) and plantar flexors (PF) at Pre‐, Post‐, and 2 days post downhill run (Post2d). Anterior patterns were associated with (a) higher gastrocnemius lateralis activity and lower tibialis anterior and vastus lateralis activity during the run and (b) larger decreases in KE high‐frequency stimulus‐evoked torque Post and larger decrements in KE MVC Post2d. High patterns variability during the run was associated with (a) smaller decreases in KE Db100 Post and MVC Post2d and (b) smaller decreases in PF MVC Post and Post2d. Anterior patterns increase the severity of KE peripheral fatigue. However, high foot strike pattern variability during the run reduced acute and delayed neuromuscular fatigue in KE and PF.     

What differentiates rearfoot strike runners with low and high vertical load rates?

BackgroundRunners with a rearfoot strike pattern typically show high vertical ground reaction force loading rates (LRs), that are associated with injuries, compared with forefoot strikers. However, some runners with a rearfoot strike pattern run in a way that reduces LRs. Our purpose was to identify differences in running mechanics between rearfoot strike runners with high and low vertical LRs.Methods42 healthy runners, 21 with high (≥ 80.5 BW/s) and 21 with low (≤ 46.3 BW/s) LRs, were included in the current study. Lower extremity kinematic and kinetic data were then collected while participants ran along a 30 m runway. Running mechanics were calculated, including sagittal plane knee stiffness during early stance, the components of knee stiffness (Δ knee flexion and flexion moment), sagittal joint angles at initial contact, as well as cadence. The two LR groups were compared for differences in outcome variables using independent t-tests or Mann Whitney U tests.FindingsKnee stiffness was significantly lower in the low LR group (p < 0.01, d = 0.87), due to higher knee flexion excursion (p < 0.01, d = 1.38). At initial contact, the low LR group showed lower hip and knee flexion, but greater ankle and foot dorsiflexion (p = 0.01–0.04, d = 0.64–0.93). No differences were found in cadence.InterpretationThese results provide potential targets, related to gait kinematics and kinetics, for gait retraining aimed at reducing LRs in rearfoot strike runners.     

Subclassification of recreational runners with a running-related injury based on running kinematics evaluated with marker-based two-dimensional video analysis

ObjectivesTo explore whether homogeneous subgroups could be discriminated within a population of recreational runners with a running-related injury based on running kinematics evaluated with marker-based two-dimensional video analysis.DesignCross-sectional.SettingResearch laboratory.ParticipantsFifty-three recreational runners (15 males, 38 females) with a running-related injury.Main outcome measuresFoot and tibia inclination at initial contact, and hip adduction and knee flexion at midstance were measured in the frontal and sagittal plane with marker-based two-dimensional video analysis during shod running on a treadmill at preferred speed. The four outcome measures were clustered using K-means cluster analysis (n = 2–10). Silhouette coefficients were used to detect optimal clustering.ResultsThe cluster analysis led to the classification of two distinct subgroups (mean silhouette coefficient = 0.53). Subgroup 1 (n = 39) was characterized by significantly greater foot inclination and tibia inclination at initial contact compared to subgroup 2 (n = 14).ConclusionThe existence of different subgroups demonstrate that the same running-related injury can be represented by different kinematic presentations. A subclassification based on the kinematic presentation may help clinicians in their clinical reasoning process when evaluating runners with a running-related injury and could inform targeted intervention strategy development.     

There is no difference in footstrike pattern distribution in recreational runners with or without anterior knee pain

BackgroundThere are no studies comparing footstrike pattern distribution between recreational runners with or without anterior knee pain.ObjectiveThe aim of this study was to investigate if there was any difference in footstrike pattern between recreational runners with or without anterior knee pain.MethodsThis cross-sectional study involved 62 runners without anterior knee pain and 60 runners with anterior knee pain. We recruited runners in public parks and amateur road running competitions. A 2D record was made using a high-speed camera with an acquisition frequency of 300 Hz and shutter speed of 300^s−1. Also, demographic information, running characteristics, knee pain characteristics, and running biomechanics variables were collected. Besides the footstrike pattern, running step length, mean velocity, footstrike angle, and ankle push-off were evaluated.ResultsThe distribution of rearfoot strike pattern was similar between groups, observed in 96.6 % of the subjects with anterior knee pain and in 93.5 % of the subjects without it. In the secondary analysis, a logistic regression was conducted, and none of the demographic information, running training characteristics, and running biomechanics variables evaluated in this study were associated with runners presenting knee pain.ConclusionRunners with or without anterior knee pain do not differ in regard to footstrike pattern. Both groups had predominantly rearfoot strike patterns, and none of the collected variables were associated with anterior knee pain on runners.     

Running mechanics during 1600 meter track runs in young adults with and without chronic ankle instability

ObjectiveTo evaluate biomechanical measures in runners with and without chronic ankle instability (CAI) using wearable sensors during two 1600 m track runs at a slow- and fast-pace.DesignObservational case-control.SettingField.Participants18 recreational runners (CAI: n = 9; Healthy: n = 9) with rearfoot strike patterns.Main outcome measuresPronation excursion, maximum pronation velocity, peak braking g, peak impact g, contact time, cycle time, and stride length of every step of two 1600 m runs were collected using RunScribe™ sensors and binned to each 400 m lap (Lap 1 to Lap 4).ResultsSignificant group-by-lap interactions were identified for contact time (p = .05) during the slow-intensity run. The CAI group had greater contact time (p = 0.05) that progressively increased with distance completed. CAI group also had higher impact g than the control group throughout the slow-intensity run (p = .03). During the fast-intensity run, significant group by lap interaction was observed for pronation excursion with the CAI group exhibiting less pronation excursion than the healthy group as the run progressed (p = .002).ConclusionsRegardless of speed, runners with CAI demonstrated altered gait mechanics compared to healthy controls. During the higher intensity run, decreased pronation excursion was observed in the CAI group and differences became more prominent as the distance increased.     

Association of previous injury and speed with running style and stride‐to‐stride fluctuations

Running‐related injuries remain problematic among recreational runners. We evaluated the association between having sustained a recent running‐related injury and speed, and the strike index (a measure of footstrike pattern, SI) and spatiotemporal parameters of running. Forty‐four previously injured and 46 previously uninjured runners underwent treadmill running at 80%, 90%, 100%, 110%, and 120% of their preferred running speed. Participants wore a pressure insole device to measure SI, temporal parameters, and stride length (S_length) and stride frequency (S_frequency) over 2‐min intervals. Coefficient of variation and detrended fluctuation analysis provided information on stride‐to‐stride variability and correlative patterns. Linear mixed models were used to compare differences between groups and changes with speed. Previously injured runners displayed significantly higher stride‐to‐stride correlations of SI than controls (P = 0.046). As speed increased, SI, contact time (T_contact), stride time (T_stride), and duty factor (DF) decreased (P < 0.001), whereas flight time (T_flight), S_length, and S_frequency increased (P < 0.001). Stride‐to‐stride variability decreased significantly for SI, T_contact, T_flight, and DF (P ≤ 0.005), as did correlative patterns for T_contact, T_stride, DF, S_length, and S_frequency (P ≤ 0.044). Previous running‐related injury was associated with less stride‐to‐stride randomness of footstrike pattern. Overall, runners became more pronounced rearfoot strikers as running speed increased.     

Variability and fluctuation in running gait cycle of trained runners and non-runners

The current study examined variability and fluctuation in the running gait cycle, focusing on differences between trained distance runners and non-runners. The two groups of participants performed treadmill running at 80%, 100%, and 120% of their preferred speed for 10 min. Stride-interval time-series were recorded during running using footswitches. The average preferred speed was significantly higher for the trained runners than for the non-runners. The trained runners showed significantly smaller variability of stride interval than did the non-runners, and at the same time the scaling exponent α evaluated by detrended fluctuation analysis tended to be smaller for the trained runners. These results suggest that expert runners can reduce variability in the trained movement without loosing dynamical degrees of freedom for spatiotemporal organization of the gait pattern.     

Loading rate increases during barefoot running in habitually shod runners: Individual responses to an unfamiliar condition

The purpose of this study was to examine the effect of barefoot running on initial loading rate (LR), lower extremity joint kinematics and kinetics, and neuromuscular control in habitually shod runners with an emphasis on the individual response to this unfamiliar condition.Kinematics and ground reaction force data were collected from 51 habitually shod runners during overground running in a barefoot and shod condition. Joint kinetics and stiffness were calculated with inverse dynamics. Inter-individual initial LR variability was explored by separating individuals by a barefoot/shod ratio to determine acute responders/non-responders.Mean initial LR was 54.1% greater in the barefoot when compared to the shod condition. Differences between acute responders/non-responders were found at peak and initial contact sagittal ankle angle and at initial ground contact. Correlations were found between barefoot sagittal ankle angle at initial ground contact and barefoot initial LR.A large variability in biomechanical responses to an acute exposure to barefoot running was found. A large intra-individual variability was found in initial LR but not ankle plantar–dorsiflexion between footwear conditions. A majority of habitually shod runners do not exhibit previously reported benefits in terms of reduced initial LRs when barefoot. Lastly, runners who increased LR when barefoot reduced LRs when wearing shoes to levels similar seen in habitually barefoot runners who do adopt a forefoot-landing pattern, despite increased dorsiflexion.     

Differences in kinetic variables between injured and noninjured novice runners: A prospective cohort study

ObjectivesThis prospective study examined differences in kinetic variables between injured and noninjured novice female and male runners and their potential contribution to RRIs.DesignA prospective cohort study.MethodsAt baseline vertical ground reaction forces were assessed with an instrumented treadmill equipped with three force measuring transducers. Female participants ran at 8 and 9 km h^?1 and male runners ran at 9 and 10 km h^?1. Primary outcome measure was a running related injury (RRI). Participants were novice female and male recreational runners and were followed during a 9-week running program with three running sessions a week.ResultsOne hundred thirty three female and seventy seven male runners participated in this study. Mean age was 37.2 years and the BMI was 23.9 kg m^?2. During the nine week running program 16.2% of the participants sustained an injury and no difference in incidence between female and male runners was seen. In injured male runners loading rate was significantly higher compared to noninjured male runners at both running speeds and contact time in the injured male group was significantly shorter at 9 km h^?1. In the group of female injured and noninjured runners no differences on kinetic or spatio-temporal variables were observed. Female runners had significantly higher loading rates compared to male runners but this did not have an effect on the incidence of RRIs.ConclusionsThis study showed that male injured runners had higher loading rates and shorter contact times than noninjured male runners. In female runners, however, no differences in kinetic or spatio-temporal variables were observed between injured and noninjured novice runners.     

Changes in gluteal muscle forces with alteration of footstrike pattern during running

Gait retraining is a common form of treatment for running related injuries. Proximal factors at the hip have been postulated as having a role in the development of running related injuries. How altering footstrike affects hip muscles forces and kinematics has not been described. Thus, we aimed to quantify differences in hip muscle forces and hip kinematics that may occur when healthy runners are instructed to alter their foot strike pattern from their habitual rear-foot strike to a forefoot strike. This may gain insight on the potential etiology and treatment methods of running related lower extremity injury. Twenty-five healthy female runners completed a minimum of 10 running trials in a controlled laboratory setting under rear-foot strike and instructed forefoot strike conditions. Kinetic and kinematic data were used in an inverse dynamic based static optimization to estimate individual muscle forces during running. Within subject differences were investigated using a repeated measures multi-variate analysis of variance. Peak gluteus medius and minimus and hamstring forces were reduced while peak gluteus maximus force was increased when running with an instructed forefoot strike pattern. Peak hip adduction, hip internal rotation, and heel-COM distance were also reduced. Therefore, instructing habitual rearfoot strike runners to run with a forefoot strike pattern resulted in changes in peak gluteal and hamstring muscle forces and hip kinematics. These changes may be beneficial to the development and treatment of running related lower extremity injury.     

Performance goals of runners are associated with the occurrence of running-related injuries

ObjectiveThe aim of this study was to evaluate the relationship between running performance goals and running-related injuries (RRIs).DesignRetrospective cross-sectional study.SettingA total of 970 recreational runners filled in an online questionnaire to collect data on personal characteristics, their running activities, RRIs, and running goals.Participants970 recreational runners, 1) without a running performance goal, who 2) trained to complete a certain distance, and who 3) trained to complete a certain distance and to participate in a specific running event.Main outcome measuresRRI, defined as any physical complaint developed during running in the previous 12 months.ResultsA statistically significant relationship was found between runners who trained for a specific running event and who also wanted to run a certain distance (OR 2.0, 95%CI 1.23–2.98) compared with runners without a running goal. (Hinder from a) Previous injury (OR 3.9, 95%CI 2.79–5.42), overweight (OR 1.6, 95%CI 1.10–2.21), and training for more than 22.5 h/year (OR 1.7, 95%CI 1.04–2.72 and OR 2.3, 95%CI 1.42–3.81) were also associated with RRIs.ConclusionRunning to achieve running goals, specifically running to complete a certain distance and to participate in an event, is associated with the occurrence of an RRI.     

Acute responses to barefoot 5 km treadmill running involve changes in landing kinematics and delayed onset muscle soreness

BackgroundBarefoot running has gained popularity among physical activity practitioners, but there is a lack of information regarding the acute adaptations to this running technique without supervision. Information about acute adaptations can help to define the best way to insert barefoot running in the routine of runners willing to, and also provide orientation for those people who want to experience this technique.Research questionWhat acute adaptations can be observed among recreational runners exposed to barefoot running?MethodsSagittal 2D kinematics, plantar pressure, foot sensitivity and delayed onset muscle soreness were compared between conditions of shod and barefoot running in 13 recreational runners who performed two trials of 5 km treadmill running.ResultsWe found an acute effect of barefoot running on foot landing that changes from a rearfoot strike to a forefoot strike pattern. This change most likely contributed to the increase in neuromuscular recruitment of calf muscles (i.e. gastrocnemius and soleus) resulting in higher perception of delayed onset muscle soreness. Barefoot running also elicited higher stride cadence. Plantar pressure before and after running revealed higher pressure in the different foot regions after barefoot running. Foot sensitivity increased after running regardless of the footwear condition.ConclusionBarefoot running has acute effects on running technique including higher perception of delayed onset muscle soreness in the 48 h following the exercise.SignificanceOur results highlight the importance of following participants for days after a first session of barefoot running in order to properly manage the acute adaptation periods as well provide precise advices for those trying the barefoot technique.     

Biomechanical running gait assessments across prevalent adolescent musculoskeletal injuries

BackgroundWhile there is substantial information available regarding expected biomechanical adaptations associated with adult running-related injuries, less is known about adolescent gait profiles that may influence injury development.Research questionsWhich biomechanical profiles are associated with prevalent musculoskeletal lower extremity injuries among adolescent runners, and how do these profiles compare across injury types and body regions?MethodsWe conducted a cross-sectional study of 149 injured adolescents (110 F; 39 M) seen at a hospital-affiliated injured runner’s clinic between the years 2016–2021. Biomechanical data were obtained from 2-dimensional video analyses and an instrumented treadmill system. Multivariate analyses of variance covarying for gender and body mass index were used to compare continuous biomechanical measures, and Chi-square analyses were used to compare categorical biomechanical variables across injury types and body regions. Spearman’s rho correlation analyses were conducted to assess the relationship of significant outcomes.ResultsPatients with bony injuries had significantly higher maximum vertical ground reaction forces (bony: 1.87 body weight [BW] vs. soft tissue: 1.79BW, p = 0.05), and a higher proportion of runners with contralateral pelvic drop at midstance (χ² =5.3, p = 0.02). Maximum vertical ground reaction forces and pelvic drop were significantly yet weakly correlated (ρ = 0.20, p = 0.01). Foot strike patterns differed across injured body regions, with a higher proportion of hip and knee injury patients presenting with forefoot strike patterns (χ² =22.0, p = 0.01).SignificanceThese biomechanical factors may represent risk factors for injuries sustained by young runners. Clinicians may consider assessing these gait adaptations when treating injured adolescent patients.     

Footwear characteristics are related to running mechanics in runners with patellofemoral pain

Running footwear is known to influence step rate, foot inclination at foot strike, average vertical loading rate (VLR) and peak patellofemoral joint (PFJ) force. However, the association between the level of minimalism of running shoes and running mechanics, especially with regards to these relevant variables for runners with patellofemoral pain (PFP), has yet to be investigated. The objective of this study was to explore the relationship between the level of minimalism of running shoes and habitual running kinematics and kinetics in runners with PFP. Running shoes of 69 runners with PFP (46 females, 23 males, 30.7 ± 6.4 years) were evaluated using the Minimalist Index (MI). Kinematic and kinetic data were collected during running on an instrumented treadmill. Principal component and correlation analyses were performed between the MI and its subscales and step rate, foot inclination at foot strike, average VLR, peak PFJ force and peak Achilles tendon force. Higher MI scores were moderately correlated with lower foot inclination (r = −0.410, P < 0.001) and lower peak PFJ force (r = −0.412, P < 0.001). Moderate correlations also showed that lower shoe mass is indicative of greater step rate (ρ = 0.531, P < 0.001) and lower peak PFJ force (ρ = −0.481, P < 0.001). Greater shoe flexibility was moderately associated with lower foot inclination (ρ = −0.447, P < 0.001). Results suggest that greater levels of minimalism are associated with lower inclination angle and lower peak PFJ force in runners with PFP. Thus, this population may potentially benefit from changes in running mechanics associated with the use of shoes with a higher level of minimalism.