Should runners change their foot strike pattern?

NewsBot · Apr 5, 2022

Differences in Peak Impact Accelerations Among Foot Strike Patterns in Recreational Runners
Christopher Napier et al
Front. Sports Act. Living, 04 March 2022

Introduction: Running-related injuries (RRIs) occur from a combination of training load errors and aberrant biomechanics. Impact loading, measured by peak acceleration, is an important measure of running biomechanics that is related to RRI. Foot strike patterns may moderate the magnitude of impact load in runners. The effect of foot strike pattern on peak acceleration has been measured using tibia-mounted inertial measurement units (IMUs), but not commercially available insole-embedded IMUs. The aim of this study was to compare the peak acceleration signal associated with rearfoot (RFS), midfoot (MFS), and forefoot (FFS) strike patterns when measured with an insole-embedded IMU.

Materials and Methods: Healthy runners ran on a treadmill for 1 min at three different speeds with their habitual foot strike pattern. An insole-embedded IMU was placed inside standardized neutral cushioned shoes to measure the peak resultant, vertical, and anteroposterior accelerations at impact. The Foot strike pattern was determined by two experienced observers and evaluated using high-speed video. Linear effect mixed-effect models were used to quantify the relationship between foot strike pattern and peak resultant, vertical, and anteroposterior acceleration.

Results: A total of 81% of the 187 participants exhibited an RFS pattern. An RFS pattern was associated with a higher peak resultant (0.29 SDs; p = 0.029) and vertical (1.19 SD; p < 0.001) acceleration when compared with an FFS running pattern, when controlling for speed and limb, respectively. However, an MFS was associated with the highest peak accelerations in the resultant direction (0.91 SD vs. FFS; p = 0.002 and 0.17 SD vs. RFS; p = 0.091). An FFS pattern was associated with the lowest peak accelerations in both the resultant and vertical directions. An RFS was also associated with a significantly greater peak acceleration in the anteroposterior direction (0.28 SD; p = 0.033) than an FFS pattern, while there was no difference between MFS and FFS patterns.

Conclusion: Our findings indicate that runners should be grouped by RFS, MFS, and FFS when comparing peak acceleration, rather than the common practice of grouping MFS and FFS together as non-RFS runners. Future studies should aim to determine the risk of RRI associated with peak accelerations from an insole-embedded IMU to understand whether the small observed differences in this study are clinically meaningful.
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NewsBot · May 2, 2022

The Coupling of Stride Length and Foot Strike in Running
Missy Thompson et al
Front Sports Act Living. 2022 Apr 12

Modifying stride length and/or foot strike in running results in mechanical alterations associated with injury risk. Stride length and foot strike have often been treated as independent factors that affect running mechanics, but there is evidence to suggest that they may be coupled. The purpose of this study was to determine if foot strike and stride length are coupled in running, and if so, can these variables be independently manipulated? Additionally, we sought to determine how independently and simultaneously manipulating stride length and foot strike influenced running kinematics and kinetics. Fifteen individuals ran over ground with stride lengths +/- 10 % of their preferred stride length while adopting both a fore/mid foot strike and rear foot strike pattern, as well as running with their self-selected stride length and foot strike when the opposite variable was controlled. Three-dimensional motion capture and force plate data were captured synchronously during the manipulated stride length x foot strike trials. The results indicate that foot strike and stride length are coupled, with shorter stride lengths being associated with a F/MFS and longer stride lengths being associated with a RFS pattern. Impact peak magnitude was primarily dependent on foot strike, with a F/MFS pattern reducing the magnitude of the impact peak force regardless of stride length. Peak vertical and horizontal ground reaction forces were found to be primarily dependent on stride length, with longer stride lengths resulting in increased vertical and horizontal ground reaction forces, regardless of foot strike. It is difficult, but possible, to independently manipulate stride length and foot strike. Clinicians should be aware of the coupled changes in stride length and foot strike.
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NewsBot · May 12, 2022

Relationship Between Ground Reaction Force Characteristics and Bone Mineral
Density of the Hip and Spine in Male Runners
MICHELE LEBLANC et al
International Journal of Exercise Science 15(1): 655-666, 2022.

The purpose of this study was to
determine the relationship between running ground reaction force (GRF) characteristics and hip and lumbar spine
bone mineral density (BMD) values in male runners. Individuals who ran at least 48.3 km per week and were injuryfree were recruited. Kistler force plates collected running vertical and anteroposterior GRF data. A Hologic
Discovery W bone densitometer measured lumbar spine and five regional hip BMD values. Only runners who
consistently used a rear foot strike pattern were included (n = 32). Pearson correlation coefficients were calculated
between BMD values and various GRF values and step-wise multiple regression was run to predict BMD values
from the various GRF values. The vertical impact force was significantly correlated with the lumbar spine and four
of the five hip BMD values (r > 0.374, p < 0.035). Both the peak early loading rate (ELR) and average ELR were
significantly correlated with the lumbar spine and Ward’s triangle BMD (r > 0.430, p < 0.014), while the average
active loading rate was correlated only with the Ward’s triangle BMD (r = 0.438, p = 0.012). Multiple regression
revealed the peak impact force was the predictor for every hip region BMD other than the trochanter and the
average ELR as a predictor for the lumbar spine BMD. The peak braking force was negatively correlated with the
Ward’s triangle BMD (r = - 0.414, p = 0.019). It appears that the large forces and loading rates associated with rear
foot striking may be advantageous and predictive for BMD at the hip and spine.
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NewsBot · May 15, 2022

A Re-examination of the Measurement of Foot Strike Mechanics During Running: The Immediate Effect of Footwear Midsole Thickness
Zhenyuan Zhang, Mark Lake
Front Sports Act Living. 2022 Apr 26;4:824183

Purpose: Midsole cushioning thickness (MT) is a key component of running footwear that may influence the stiffness setting of the joints, performance enhancement, and injury prevention. Most studies that have investigated the influence of manipulating shoe midsole characteristics on foot strike patterns and vertical force loading rates have not considered the dynamic conditions of initial landing and the associated initial lower limb joint stiffness. In this study, we examined the effect of running in shoes with large changes in MT on both the posture and dynamics associated with foot strike.

Methods: 12 injury-free runners with habitual rearfoot strike patterns ran at 4.5 m/s along a 40-m runway in shoe conditions with MT of 30, 42, and 54 mm, respectively. Ground reaction force and the right leg kinematic data were collected. One-way repeated measures ANOVA was conducted to statistically analyze the effect of MT on key variables linked to foot strike.

Results: Increased midsole thickness resulted in a slightly flatter foot strike posture (p < 0.05), a decreased shank retraction velocity (p < 0.05), and an increase in forward horizontal foot velocity (p < 0.05), all at initial ground contact. Vertical force loading rates were reduced with increasing MT (p < 0.05), but this was associated with large increases in the initial ankle and knee joint stiffness (p < 0.05).

Conclusion: Adjustments in the initial conditions of contact with the ground during running were seen in both the posture and dynamics of the lower limbs. To help to mitigate the impact severity from foot-ground collision with the thinnest shoe condition, there was an increased shank retraction velocity and decreased forward velocity of the foot at landing. These active impact-moderating adaptations likely served to reduce the changes in impact severity expected due to midsole material properties alone and should be considered in relation to altering the risk of running-related injuries.
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NewsBot · May 16, 2022

Strike index estimation using a convolutional neural network with a single, shoe-mounted inertial sensor
TianTan et al
Journal of Biomechanics; 15 May 2022, 111145
Strike index is a measurement of the center of pressure position relative to the foot length, and it is regarded as a gold standard in classifying strike pattern in runners. However, strike index requires sophisticated laboratory equipment, e.g., force plates and optical motion capture. We present a method of estimating strike index using data from a shoe-mounted inertial measurement unit (IMU) analyzed by a participant-independent convolutional neural network (CNN), which consists of convolutional, max-pooling, and fully-connected layers. To promote data variability, 16 participants were required to land with three strike patterns (rearfoot, midfoot, and forefoot strike) while running on an instrumented treadmill in four conditions i.e., two footwear types and two running speeds. Using the proposed approach, strike index was estimated with a root mean square error of 6.9% and a R2 of 0.89. Training and testing the model with different variations of the data collected showed that the model was robust to changes in speed. The proposed approach enables accurate estimation of strike index outside of traditional gait laboratories. This solution potentially improves running performance and reduces injury risk in distance runners.

NewsBot · May 27, 2022

Reversing the Mismatch With Forefoot Striking to Reduce Running Injuries
Irene S. Davis et al
Front. Sports Act. Living, 19 May 2022

Recent studies have suggested that 95% of modern runners land with a rearfoot strike (RFS) pattern. However, we hypothesize that running with an RFS pattern is indicative of an evolutionary mismatch that can lead to musculoskeletal injury. This perspective is predicated on the notion that our ancestors evolved to run barefoot and primarily with a forefoot strike (FFS) pattern. We contend that structures of the foot and ankle are optimized for forefoot striking which likely led to this pattern in our barefoot state. We propose that the evolutionary mismatch today has been driven by modern footwear that has altered our footstrike pattern. In this paper, we review the differences in foot and ankle function during both a RFS and FFS running pattern. This is followed by a discussion of the interaction of footstrike and footwear on running mechanics. We present evidence supporting the benefits of forefoot striking with respect to common running injuries such as anterior compartment syndrome and patellofemoral pain syndrome. We review the importance of a gradual shift to FFS running to reduce transition-related injuries. In sum, we will make an evidence-based argument for the use of minimal footwear with a FFS pattern to optimize foot strength and function, minimize ground reaction force impacts and reduce injury risk.
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NewsBot · Jun 5, 2022

Simple foot strike angle calculation from three-dimensional kinematics: A methodological comparison
Stephanie R. Moore et al
Journal of Sports Sciences

A simple and accurate method of determining foot strike angle (FSA) during running can simplify data collections and validations of wearable sensors. The purpose of this study was to determine the validity of two simplified methods for estimating FSA and foot angle (throughout the ground contact) from three-dimensional kinematics. Markers were placed on the heel and head of the second metatarsal (HEEL-TOE) or on the lateral side of the head of the fifth metatarsal (HEEL-MET5). When compared to the reference foot segment, the HEEL-TOE method performed similarly with a minimal mean difference (0.28° [0.19°,0.36°], p < 0.001), a high Pearson’s r (r = 0.994; p < 0.001), and low bias (−0.20°±1.05°). Alternatively, the HEEL-MET5 method underestimated FSA: mean difference = 4.28° [4.07°,4.91°] (p < 0.001), Pearson’s r = 0.968 (p < 0.001), and bias = −4.58°±2.61°. Throughout the contact phase, significant SPM cluster regions were identified, indicating that the HEEL-MET5 method underestimated the angle of the foot for all foot strike patterns in the first 23–34% of the stance (p < 0.025). This study supports the idea that the HEEL-TOE method can be used as a simplified method for determining FSA from 3D kinematics. Researchers should proceed with caution when employing the HEEL-MET5 method, as it is likely underestimating FSA due to foot inversion in the early stance phase.
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NewsBot · Jun 6, 2022

Plantar loads characteristics of male non-rearfoot strikers running on different overground surfaces at preferred speed
Zhangqi Lai et al
J. Mens. Health 2022 , 18(5), 105; https://doi.org/10.31083/j.jomh1805105

Background: This study aimed to investigate the plantar loads of male non-rearfoot strike runners running on different overground surfaces at their preferred speeds. Methods: A total of 32 male runners with non-rearfoot strike were required to run for 15 m on concrete, synthetic rubber and grass surfaces at their preferred speeds. An insole sensor system was used to determine the runners’ foot strike pattern and measure peak pressure, pressure-time integral, maximum force, force-time integral and contact area of the total foot and nine selected foot regions. Results: No significant differences on their preferred speeds were observed running on concrete, synthetic rubber and grass surfaces. No significant differences on plantar loads parameters of the total foot were found when running on the three overground surfaces. Running on concrete showed higher peak pressure in the lateral forefoot compared with grass and synthetic rubber (283.49 kPa vs. 264.31 kPa, P
<
0.023; 283.49 kPa vs. 263.18 kPa, P
<
0.019, respectively). Maximum force in the medial forefoot was lower when running on concrete compared with grass and synthetic rubber (40.16 %BW vs. 42.52 %BW, P
<
0.042; 40.16 %BW vs. 43.21 %BW, P
<
0.022, respectively). Conclusions: Repetitive and excessive plantar loads during long-distance running may result in loads-related injury in lower extremity skeletal tissues for non-rearfoot runners at preferred speeds. Therefore, male non-rearfoot strikers should choose the appropriate overground surface to reduce the risk of lower extremity musculoskeletal injuries.
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NewsBot · Jun 13, 2022

What differentiates rearfoot strike runners with low and high vertical load rates?
Caleb D.JohnsonIrene S.Davis
Gait & Posture; Volume 96, July 2022, Pages 149-153

Highlights
•Rearfoot strike runners who land softer displayed differences in gait mechanics.
•They had lower early stance knee stiffness, due to higher knee flexion excursion.
•They had higher initial contact ankle/foot flexion and hip extension.
•These may be viable gait retraining targets to reduce loading in rearfoot strikers.
•No differences were found in cadence or initial contact knee flexion.
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Background
Runners 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.

Methods
42 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.

Findings
Knee 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.

Interpretation
These results provide potential targets, related to gait kinematics and kinetics, for gait retraining aimed at reducing LRs in rearfoot strike runners.
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NewsBot · Jun 21, 2022

Current perception and practice of athletics coaches about the modification of footstrike pattern in endurance runners: A survey
Guillaume Abran, François Delvaux, Cédric Schwartz, ...
International Journal of Sports Science & Coaching June 14, 2022

Purpose
To date, the relationship between footstrike pattern and performance, as well as with injury incidence in endurance running remains unclear. For these reasons, it is currently not recommended to modify footstrike pattern in an uninjured long-distance runner. The purpose of this study was to analyse whether athletic coaches apply these current scientific recommendations with their endurance runners on the field.

Methods
A Delphi method study was used to develop an online survey that was administered to French-speaking athletic coaches in Belgium. The survey comprised three sections: 1) coaches’ profile, 2) coaches’ perception of footstrike patterns, 3) practices pertaining to footstrike patterns.

Results
One hundred and fourteen respondents completed the entire questionnaire. Ninety-six (84%) athletic coaches reported modifying the footstrike pattern of their endurance runners. They reported that they modify their runners’ rearfoot and forefoot strike more often than a midfoot strike (P < 0.0001) to prevent injury (83%) and to improve performance (66%). According to them, midfoot strike is considered as the best landing pattern for endurance performance (47%) and injury prevention (36%) whereas rearfoot strike is considered as the worst (respectively, 50% and 52%).

Summary and conclusion
This study highlights the disparities between scientific recommendations and athletic coaches’ field practices for modifying footstrike patterns in endurance runners. Contrary to current scientific literature recommendations, a large proportion of coaches modify the natural footstrike pattern of their endurance runners towards a midfoot strike pattern to improve performance and prevent injury.
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NewsBot · Jun 21, 2022

Temporal differences in the myoelectric activity of lower limb muscles during rearfoot and forefoot running: A statistical parametric mapping approach
Oscar Valencia et al
European Journal of Sport Science

The aim of this study was to apply statistical parametric mapping (SPM) to compare temporal changes in EMG amplitude between rearfoot (RF) and forefoot (FF) running techniques. Eleven recreational runners ran on a treadmill at a self-selected speed, once using a RF strike pattern and once using a FF strike pattern (randomized order). The myoelectric activity of five lower limb muscles [rectus femoris (RFe), biceps femoris (BF), tibialis anterior (TA), medial and lateral gastrocnemius (MG and LG)] was evaluated, using bipolar electromyography (EMG). EMG data from the RF and FF running techniques was then processed and posteriorly compared with SPM, dividing the analysis of the running cycle into stance and swing phases. The MG and LG muscles showed higher activation during FF running at the beginning of the stance phase and at the end of the swing phase. During the end of the swing phase the TA muscle’s EMG amplitude was higher, when the RF running technique was used. A higher level of co-activation between the gastrocnemius and TA muscles was observed at the end of the swing phase during RF running. The myoelectric behaviour of the RFe and BF muscles was similar during both running techniques. These findings highlight the importance of SPM for the accurate assessment of differences in muscle activity during running and strongly suggest that these two running techniques predominately reflect adjustments of the leg and not the thigh muscles.
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NewsBot · Jul 12, 2022

Exerted running results in altered impact mechanics and footstrike patterns following gait retraining
Erin E. Futrell,K. Douglas Gross,David R. Mullineaux&Irene S. Davis
17 Feb 2021

Exertion may alter running mechanics and increase injury risk. Effects of exertion following gait-retraining are unknown. Objectives: To determine how exertion effects load rates, footstrike, and cadence in runners following a transition to forefoot strike (FFS) or increased cadence (CAD) gait-retraining. Methods: 33 (9 M, 24 F) healthy rearfoot strike runners were randomized into CAD or FFS groups. All runners received strengthening exercises and gait-retraining. 3D kinetic and kinematic motion analysis with instrumented treadmill at self-selected speed was performed at baseline & 1-week post-intervention, including an exerted run. Exertion was ≥17 on Borg’s Rating of Perceived Exertion scale or voluntary termination of running. Results: Within group comparisons between fresh and exerted running: Cadence not affected in either group. Foot angle at contact became less plantarflexed in FFS (−2.2°, ±0.4) and was unchanged in CAD. Both groups increased vertical average load rate (FFS +16.9%, CAD +13.6%). CAD increased vertical stiffness (+8.6 kN/m). FFS reduced ankle excursion (1.8°). (p ≤ 0.05 for all values listed). Conclusion: Both FFS and CAD exhibited increased load rates with exertion. Variables that may have increased load rates were different for each group. CAD runners had increased vertical stiffness while FFS runners had reduced plantarflexion at contact and reduced ankle dorsiflexion excursion.
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NewsBot · Jul 15, 2022

The Automatic Strike-Change Phenomenon: When Running Barefoot Patients Change from a Heel
Strike to a Forefoot Strike Without Any Instruction.
Wes Zimmermann, Naomi van Valderen.
International Journal of Sports Science and Physical Education. Vol. 6, No. 1, 2021, pp. 1-7.

The department of Military Sports Medicine of the Royal Netherlands Army has an ongoing research line
‘Exercise-Related Leg Pain’ since 2011. This study investigated which immediate changes occur in running technique while
running barefoot or in minimalist running shoes on a treadmill, which proportion of service members automatically changed
from a heel strike landing to a forefoot strike landing without any instruction to do so, and whether these patients experienced a
subsequent gait retraining program as easier and completed it faster or with a better clinical outcome. In total, data from 53
patients with exercise-related leg pain were used to answer the research questions. Running barefoot, 24.5% of patients
automatically changed from a heel strike landing to a forefoot strike landing (16.7% of the men, 54.5% of the women), in
minimalist shoes the percentage of automatic strike-changers was 5.7% (2,4% of men, 16.2% of women). Running barefoot, the
patients used shorter strides and a higher cadence than in traditional running shoes and the vertical ground reaction forces under
the midfoot and heel were lower. Automatic strike-changers were not better candidates for the treatment program, in terms of
subjective ease of the gait retraining sessions and duration or outcome of the treatment program. Running barefoot is a helpful
methodology to facilitate gait retraining.
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NewsBot · Jul 28, 2022

Does the Achilles Tendon Influence Foot Strike Patterns During an Exhaustive Run?
Jan Urbaczka et al
J Appl Biomech. 2022 Jul 14;1-8

The study purpose was to investigate whether there is a relationship between the Achilles tendon (AT) length, moment arm length, and the foot strike pattern (FP) change during an exhaustive run (EXR) in nonrearfoot FP runners. Twenty-eight runners were recruited and divided into 2 groups (highly trained/moderately trained) according to their weekly training volume. Participants underwent the graded exercise test, the EXR with biomechanical analysis at the beginning, and at the end, and the magnetic resonance imaging scan of the AT. Correlations were used to assess associations between FP change (value of the difference between end and beginning) and the selected performance and AT variables. AT length significantly correlated with the FP change according to foot strike angle (r = -.265, P = .049). The AT moment arm length significantly correlated with the FP change according to strike index during EXR (r = -.536, P = .003). Multiple regression showed that AT length was a significant predictor for the FP change according to foot strike angle if the second predictor was the graded exercise test duration and the third predictor was training group association. These results suggest that a runner's training volume, along with a longer AT and AT moment arm appear to be associated with the ability to maintain a consistent FP during EXR by nonrearfoot FP runners.
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NewsBot · Sep 19, 2022

Adaptive locomotion: Foot strike pattern and limb mechanical stiffness while running over an obstacle
Roxanne J Larsen et al
J Biomech. 2022 Sep 6

Previous studies of level running suggest runners adjust foot strike to control leg stiffness. This study aimed to determine how runners adjusted mechanical stiffness and foot strike prior to, during, and after a drop in surface height. Ten healthy subjects (5 male, 5 female; 24.32 ± 5.0 years) were video recorded as they ran on an outdoor path with a single drop in surface height (12.5 cm). Foot strike was recorded, while subject velocity, duty factor (DF), normalized maximum ground reaction force (GRFbw), vertical hip displacement (Δy), leg compression (ΔL), vertical (Kvert) and leg stiffness (Kleg), touchdown (TD) and takeoff angle (TO), and flight (Tf) and contact time (Tc) were calculated. Compared to the step before the drop, Tf, GRFbw, Kvert, Kleg, and TO increased, while Tc, DF, Δy, ΔL, and TD decreased in the step after the drop. Across trials, runners had either consistent or variable foot strike patterns. Runners using a consistent pattern most often shifted from rear to fore-foot strike in the steps before and after the drop, while those with a variable pattern showed less dramatic shifts. All parameters, except TD, were significantly different (p < 0.04) based on foot strike pattern, and comparisons between steps before and after the drop (except TD) were significantly different (p < 0.004). Runners with a variable foot strike pattern experienced smaller shifts within mechanical parameters when traveling over the drop, suggesting these runners may be able to stabilize limb mechanics on interrupted surfaces.
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NewsBot · Oct 10, 2022

Isolated effects of footwear structure and cushioning on running mechanics in habitual mid/forefoot runners
A H Gruber et al
Sports Biomech. 2022 Oct 6;1-20

The true differences between barefoot and shod running are difficult to directly compare because of the concomitant change to a mid/forefoot footfall pattern that typically occurs during barefoot running. The purpose of this study was to compare isolated effects of footwear structure and cushioning on running mechanics in habitual mid/forefoot runners running shod (SHOD), barefoot (BF), and barefoot on a foam surface (BF+FOAM). Ten habitually shod mid/forefoot runners were recruited (male = 8, female = 2). Repeated measures ANOVA (α = 0.05) revealed differences between conditions for only vertical peak active force, contact time, negative and total ankle joint work, and peak dorsiflexion angle. Post hoc tests revealed that BF+FOAM resulted in smaller vertical active peak magnitude and instantaneous vertical loading rate than SHOD. SHOD resulted in lower total ankle joint work than BF and BF+FOAM. BF+FOAM resulted in lower negative ankle joint work than either BF or SHOD. Contact time was shorter with BF than BF+FOAM or SHOD. Peak dorsiflexion angle was smaller in SHOD than BF. No other differences in sagittal joint kinematics, kinetics, or ground reaction forces were observed. These overall similarities in running mechanics between SHOD and BF+FOAM question the effects of footwear structure on habituated mid/forefoot running described previously.
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NewsBot · Nov 30, 2022

The impact of local muscle fatigue and foot strike techniques on kinematic features and plantar pressure distribution while walking
Aly Hazzaa Walaa Eldin, Klaus Mattes
Sportverletz Sportschaden. 2022 Dec;36(4):178-187

Although numerous studies have been performed, there are no clear findings providing a meaningful statement about how foot strike changes as a result of muscular fatigue. In studies on running fatigue, it is not possible to differentiate which kinematic or kinetic changes are a direct result of local muscle fatigue and varied speeds. This study aimed to investigate the effect of foot strike technique and localized muscle fatigue of the plantar and dorsal flexors on plantar pressure distribution and selected kinematic features of treadmill running. Twenty-six voluntary forefoot and rearfoot runners of similar age and body mass participated in the study. Each group completed two tests with a time interval of 3-7 days. The kinematic data was measured with the help of a three-dimensional measuring and analysis system while the volunteers ran on the treadmill. The fatigue protocol included an isometric maximal force test and an isokinetic endurance test. In order to check the differences, a variance analysis with repeated measurements was used. The strength values of the two groups of runners showed significant average differences in the plantar flexors in the endurance test and in the fatigue index for both the left and right legs. The results of the strength values are surprising because the plantar flexors of this group of runners should be well-trained due to the forefoot strike during regular running. In response to fatigue, the pressure maxima decreased under the exposed foot regions, i.e. under the forefoot at forefoot strike and under the heel at rearfoot strike. The two groups of runners differed in foot angle at foot-on with higher values measured in the forefoot runners. The larger foot angle of the forefoot runners improved shock absorption and can thus reduce the risk of injury.
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NewsBot · Dec 11, 2022

Kinematics Analysis of Male Runners via Forefoot and Rearfoot Strike Strategies: A Preliminary Study
Chao-Fu Chen et al
Int J Environ Res Public Health. 2022 Nov 29;19(23):15924

This study aimed to explore the kinematic characteristics of males using various foot landing strategies. The participants were fifteen male students from Physical Education College, Huaibei (non-professional runners, who did not have a fixed running landing strategy mode) (mean height = 178.20 cm; mean weight = 67.60 kg; mean age = 19.40 years). In this experiment, the running model of different foot landing strategies (forefoot strike, FFS and rearfoot strike, RFS) were analyzed using two high-speed cameras captured simultaneously at a sampling rate of 100 Hz. According to the results, the runners with better sports performance have shorter contact time, longer flight time, lower duty factor, larger stride angle, faster V COG, greater A COG, and knee and ankle angles which were crucial kinematics factors to enhance the running. Therefore, this study recommends that coaches or researchers can use photography to analyze novice runners who do not have a fixed landing pattern when running with RFS, the characteristics of running style was closely related to the flight times, and running with FFS was closely related to the stride angle.
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NewsBot · Jan 17, 2023

Validity and reliability of inertial measurement units measurements for running kinematics in different foot strike pattern runners
Ziwei Zeng et al
Front Bioeng Biotechnol. 2022 Dec 8

This study aimed to assess the validity and reliability of the three-dimensional joint kinematic outcomes obtained by the inertial measurement units (IMUs) for runners with rearfoot strike pattern (RFS) and non-rearfoot strike pattern (NRFS). The IMUs system and optical motion capture system were used to simultaneous collect 3D kinematic of lower extremity joint data from participants running at 12 km/h. The joint angle waveforms showed a high correlation between the two systems after the offset correction in the sagittal plane (NRFS: coefficient of multiple correlation (CMC) = 0.924-0.968, root mean square error (RMSE) = 4.6°-13.7°; RFS: CMC = 0.930-0.965, RMSE = 3.1°-7.7°), but revealed high variability in the frontal and transverse planes (NRFS: CMC = 0.924-0.968, RMSE = 4.6°-13.7°; RFS: CMC = 0.930-0.965, RMSE = 3.1°-7.7°). The between-rater and between-day reliability were shown to be very good to excellent in the sagittal plane (between-rater: NRFS: CMC = 0.967-0.975, RMSE = 1.9°-2.9°, RFS: CMC = 0.922-0.989, RMSE = 1.0°-2.5°; between-day: NRFS: CMC = 0.950-0.978, RMSE = 1.6°-2.7°, RFS: CMC = 0.920-0.989, RMSE = 1.7°-2.2°), whereas the reliability was weak to very good (between-rater: NRFS: CMC = 0.480-0.947, RMSE = 1.1°-2.7°, RFS: CMC = 0.646-0.873, RMSE = 0.7°-2.4°; between-day: NRFS: CMC = 0.666-0.867, RMSE = 0.7°-2.8°, RFS: CMC = 0.321-0.805, RMSE = 0.9°-5.0°) in the frontal and transverse planes across all joints in both types of runners. The IMUs system was a feasible tool for measuring lower extremity joint kinematics in the sagittal plane during running, especially for RFS runners. However, the joint kinematics data in frontal and transverse planes derived by the IMUs system need to be used with caution.
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NewsBot · Jan 24, 2023

Influences of altering footstrike pattern and cadence on lower extremity joint coordination and variability among runners with patellofemoral pain
Yue Liu,Yujie Qi,Yanliqing Song,Li Feng,Lin Wang
January 23, 2023

Background
Patellofemoral pain (PFP) is a common overuse injury among runners. It is not only a hindrance to the runner’s training, but also to the runner’s quality of life. PFP runners may strategize different running strategies to reduce patellofemoral joint stress, release pain, and improve function.

Purpose
This study aimed to determine the changes in joint coordination and variability under combinations of foot strike pattern and cadence for runners with patellofemoral pain.

Methods
Twenty male runners with PFP performed six running strategies which were two strike patterns named forefoot (FFS) and rearfoot (RFS) accompanied by three running cadences named slow10%, normal, and fast10%. A modified vector coding technique and circular statistics were respectively used to identify the coordination pattern and variability between hip sagittal-knee frontal (HsKf), hip sagittal-knee sagittal (HsKs) and knee transverse-ankle frontal (KtAf) during stance phase. Coordination patterns which were conformed with anatomical motion pattern was classified as mechanically sound, and the distribution frequency of each coordination pattern was quantified.

Results
Switching to FFS, the HsKf couples (p < 0.001, ES = 1.34) and the HsKs couples (p = 0.001, ES = 0.82) displayed significantly greater frequency in mechanically unsound coordination pattern during the initial stance phase. The effect of increasing running cadence on RFS displayed significantly greater frequency in mechanically unsound hip dominancy (p = 0.042, ES = 0.65) and knee dominancy (p = 0.05, ES = 0.70) coordination patterns for HsKf couples as well as for HsKs couples (p = 0.023, ES = 0.86) during the initial stance phase. Combined with FFS and fast10% cadence, HsKs couples showed more hip-dominated mechanical sound coordination pattern (p = 0.002, ES = 1.25). Further, altering footstrike pattern and cadence failed to change the coordination variability.

Conclusions
Changing running cadence (± 10%) combined with transfer strike pattern from RFS to FFS could not increase the distribution frequency in mechanically sound coordination patterns and change coordination variability for PFP runners.
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NewsBot · Jan 31, 2023

Biomechanical Analysis of Foot–Ankle Complex during Jogging with Rearfoot Strike versus Forefoot Strike
Yaoyong Zhang1and Dan Zhang
Source

Background and Aim. In order to reduce foot and ankle injuries induced by jogging, two-foot strike patterns, rearfoot strike (RFS), and forefoot strike (FFS), were adopted and compared. First, RFS jogging and FFS jogging were experimentally studied, so as to acquire kinematic and kinetic data, including foot strike angle, knee flexion angle, and ground reaction force (GRF). Then, a 3D finite element model of foot–ankle complex was reconstructed from the scanned 2D-stacked images. Biomechanical characteristics, including plantar pressure, stress of metatarsals, midfoot bone, calcaneus and cartilage, and tensile force of plantar fascia and ligaments, were obtained. The results showed that RFS jogging and FFS jogging had a similar change trend and a close peak value of GRF. Since possessing more momentum in the push stage and less momentum in the brake stage, FFS jogging could be in favor of a higher jogging speed. However, FFS jogging produced larger metatarsal stress in the 5th metatarsal and much larger tensile force of plantar fascia, which might cause metatarsal fracture and heel pain. While RFS jogging produced larger plantar pressure in the hindfoot area, larger calcaneus stress, and much larger tarsal navicular stress, which might cause heel tissue injury, calcaneus damage, and stress fracture of naviculocuneiform joint. In addition, talocrural and talocalcaneal joint cartilage could bear jogging loads, as the peak contact pressure were both small in RFS jogging and FFS jogging. Therefore, jogging with rearfoot or FFS pattern should be chosen according to the health condition of foot–ankle parts.
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NewsBot · Feb 27, 2023

The Effects of Habitual Foot Strike Patterns on the Morphology and Mechanical Function of the Medial Gastrocnemius-Achilles Tendon Unit
Lu Li et al
Bioengineering (Basel). 2023 Feb 17;10(2):264

As a crucial and vulnerable component of the lower extremities, the medial gastrocnemius-Achilles tendon unit (gMTU) plays a significant role in sport performance and injury prevention during long-distance running. However, how habitual foot strike patterns influence the morphology of the gMTU remains unclear. Therefore, this study aimed to explore the effects of two main foot strike patterns on the morphological and mechanical characteristics of the gMTU. Long-distance male runners with habitual forefoot (FFS group, n = 10) and rearfoot strike patterns (RFS group, n = 10) and male non-runners (NR group, n = 10) were recruited. A Terason uSmart 3300 ultrasonography system was used to image the medial gastrocnemius (MG) and Achilles tendon, Image J software to analyze the morphology, and a dynamometer to determine plantar flexion torque during maximal voluntary isometric contractions. The participants first performed a 5-minute warm up; then, the morphological measurements of MG and AT were recorded in a static condition; finally, the MVICs test was conducted to investigate the mechanical function of the gMTU. One-way ANOVA and nonparametric tests were used for data analysis. The significance level was set at a p value of <0.05. The muscle fascicle length (FL) (FFS: 67.3 ± 12.7, RFS: 62.5 ± 7.6, NRs: 55.9 ± 2.0, η2 = 0.187), normalized FL (FFS: 0.36 ± 0.48, RFS: 0.18 ± 0.03, NRs: 0.16 ± 0.01, η2 = 0.237), and pennation angle (PA) (FFS: 16.2 ± 1.9, RFS: 18.9 ± 2.8, NRs: 19.3 ± 2.4, η2 = 0.280) significantly differed between the groups. Specifically, the FL and normalized FL were longer in the FFS group than in the NR group (p < 0.05), while the PA was smaller in the FFS group than in the NR group (p < 0.05). Conclusion: Long-term running with a forefoot strike pattern could significantly affect the FL and PA of the MG. A forefoot strike pattern could lead to a longer FL and a smaller PA, indicating an FFS pattern could protect the MG from strain under repetitive high loads.
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NewsBot · Mar 10, 2023

Footstrike angle cut-off values to classify footstrike pattern in runners
Shiwei Mo et al
Research in Sports Medicine

Footstrike angle (FSA) has been widely used to classify footstrike pattern (FSP). However, inconsistent FSA cut-off values were adopted in previous studies. This study aimed to validate the FSA cut-off values in runners. Stride index, the gold standard to determine FSP, and FSA were obtained when 15 experienced runners, 14 novice runners and 14 untrained individuals performed 3-min run on an instrumented treadmill at their preferred running speeds in habitual, rearfoot, midfoot and forefoot strike patterns. According to the receiver operating characteristic curve associated with the Youden index, the optimal FSA cut-off values were −0.8° (i.e., cut-off angle for forefoot strike) –7.4° (i.e., cut-off angle for rearfoot strike) for runners. We observed minor differences in the FSA cut-off values across runners with various running experience and a wider cut-off range for midfoot strikers when a modified strike index was utilized. This validation study established cut-off footstrike angles for runners’ FSP classification.
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Should runners change their foot strike pattern?

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Should runners alternate their running shoes .

Should We Retrain the Gait of Asymptomatic Runners?

Arch Supports should NOT be used in treating a Flexible Flatfoot

Do we all have feet half as strong as they should be ?

Should Adolescents Run Marathons?

Should We Abandon The Concept Of The Subtalar Neutral Joint Position?

Should existing forefoot injuries be addressed with HAV surgery?

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Should runners change their foot strike pattern?

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Should runners alternate their running shoes .

Should We Retrain the Gait of Asymptomatic Runners?

Arch Supports should NOT be used in treating a Flexible Flatfoot

Do we all have feet half as strong as they should be ?

Should Adolescents Run Marathons?

Should We Abandon The Concept Of The Subtalar Neutral Joint Position?

Should existing forefoot injuries be addressed with HAV surgery?

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