Long-term effects of school barefoot running program on sprinting biomechanics in children: A case-control study

BackgroundThe acute changes of running biomechanics in habitually shod children when running barefoot have been demonstrated. However, the long-term effects of barefoot running on sprinting biomechanics in children is not well understood.Research questionHow does four years of participation in a daily school barefoot running program influence sprint biomechanics and stretch-shortening cycle jump ability in children?MethodsOne hundred and one children from barefoot education school (age, 11.2 ± 0.7 years-old) and 93 children from a control school (age, 11.1 ± 0.7 years-old) performed 50 m maximal shod and barefoot sprints and counter movement jump and five repeated-rebound jumping. To analyse sprint kinematics, a high-speed camera (240 fps) was used. In addition, foot strike patterns were evaluated by using three high-speed cameras (300 fps). Jump heights for both jump types and the contact times for the rebound jump were measured using a contact mat system. Two-way mixed ANOVA was used to examine the effect of school factor (barefoot education school vs control school) and footwear factor (barefoot vs shod) on the sprinting biomechanics.ResultsSprinting biomechanics in barefoot education school children was characterised by significantly shorter contact times (p = 0.003) and longer flight times (p = 0.005) compared to control school children regardless of footwear condition. In shod sprinting, a greater proportion of barefoot education school children sprinted with a fore-foot or mid-foot strike compared to control school children (p < 0.001). Barefoot education school children also had a significantly higher rebound jump height (p = 0.002) and shorter contact time than control school children (p = 0.001).SignificanceThe results suggest that school-based barefoot running programs may improve aspects of sprint biomechanics and develop the fast stretch-shortening cycle ability in children. In order to confirm this viewpoint, adequately powered randomised controlled trials should be conducted.     

A comparison of the kinematics and kinetics of barefoot and shod running in children with cerebral palsy

BackgroundThe biomechanics of barefoot and shod running are different for typically developing children but unknown for children with cerebral palsy (CP). Such differences may have implications for injury and performance.AimsThe primary aims of this study were to compare the lower limb biomechanics of barefoot and shod running in children with CP, and to determine whether any differences were the same in GMFCS levels I and II.MethodsThis cross-sectional study examined 38 children with CP (n = 24 (GMFCS) level I; n = 14 GMFCS II), running overground at 3 speeds (jog, run, sprint) in barefoot and shod conditions. Marker trajectories and force plate data were recorded, and lower limb kinematics, kinetics and spatiotemporal variables were derived. Differences between barefoot and shod running were analysed using linear mixed models.ResultsFor both GMFCS levels, barefoot running resulted in higher loading rates, but smaller impact peaks at all speeds. Barefoot running was associated with greater hip and knee power; less ankle dorsiflexion and hip flexion at initial contact, and less ankle and knee range of motion during stance, compared to shod running, at all speeds. Barefoot stride length was shortened, and cadence increased compared to shod during jogging and running but not sprinting. For GMFCS level I only, barefoot running involved a higher incidence of forefoot strike, greater ankle power generation and less hip range of motion during stance.SignificanceRunning barefoot may facilitate running performance by increasing power generation at the ankle in children with CP, GMFCS level I. Higher barefoot loading rates may have implications for performance and injury.     

Center of pressure trajectory differences between shod and barefoot running

This study examined differences in center of pressure (COP) trajectories between shod and barefoot running. Ten habitually shod runners ran continuous laps under both shod and barefoot conditions. The COP trajectory was calculated in the global coordinate system but then transformed to the anatomic coordinate system of the foot. The anterior–posterior and medio-lateral positions and excursions of the COP, as well as the most medial location and percent stand at which it occurred were examined. Additionally, external eversion moments and ground reaction forces were assessed. Compared to the shod condition, in the barefoot condition the COP was located more anteriorly early in stance and the COP was located significantly more medially at most time points across stance. There were no differences in external eversion moments during early stance or peak ground reaction forces between conditions. Future studies on mechanical or epidemiological differences between shod and barefoot running may find the COP trajectory an informative parameter to examine.     

Center of pressure trajectory differences between shod and barefoot running

This study examined differences in center of pressure (COP) trajectories between shod and barefoot running. Ten habitually shod runners ran continuous laps under both shod and barefoot conditions. The COP trajectory was calculated in the global coordinate system but then transformed to the anatomic coordinate system of the foot. The anterior–posterior and medio-lateral positions and excursions of the COP, as well as the most medial location and percent stand at which it occurred were examined. Additionally, external eversion moments and ground reaction forces were assessed. Compared to the shod condition, in the barefoot condition the COP was located more anteriorly early in stance and the COP was located significantly more medially at most time points across stance. There were no differences in external eversion moments during early stance or peak ground reaction forces between conditions. Future studies on mechanical or epidemiological differences between shod and barefoot running may find the COP trajectory an informative parameter to examine.     

The effect of body weight reduction using a lower body positive pressure treadmill on plantar pressure measures while running

ObjectiveTo evaluate the effects of body weight reduction at 10% intervals on pressure distribution variables across regions of the foot while running.Study designCrossover Study Design.SettingLaboratory.Participants12 recreational runners.Main outcome measuresPressure-time integral, peak pressure, instance of peak pressure, contact area, contact time and center of pressure (COP) location at initial contact across four foot regions were measured while participants ran at self-selected speed on the Lower Body Positive Pressure Treadmill (LBPPT) at 100%, 90%, 80%, 70% and 60% of their body weight (%BW).ResultsAs the %BW decreased, there were corresponding significant decreases in the pressure-time integral and peak pressures in all four regions of the foot. Significant differences within foot region and %BW for the other variables were infrequent. There was a significant anterior shift of the COP location at initial contact as the %BW decreased.ConclusionLBPPT is useful for reducing the pressure across the entire foot. Additionally, the anterior translation of the COP location at initial contact with reduced %BW may provide an additional gait retraining tool for prevention and treatment of running injuries as reducing %BW moves the runner away from a rearfoot strike pattern.     

The influence of shoe aging on children running biomechanics

Athletic children are prone to overuse injuries, especially at the heel and knee. Since footwear is an extrinsic factor of lower limb injury risk, the aim of this study was to assess the influence of shoe aging on children running biomechanics. Fourteen children active in sports participated in a laboratory biomechanical evaluation. A new pair of shoes was provided to each participant at an inclusion visit. Four months later, the participants performed a running task and their kinematics and kinetics were assessed both with their used shoes and with a new pair of shoes identical to the first. Furthermore, mechanical cushioning properties of shoes were evaluated before and after in-vivo aging. After 4 months of use, the sole stiffness increased by 16% and the energy loss capacity decreased by 18% (p < 0.001). No ankle or knee kinematic adjustment was found at foot strike in used shoes but changes were observed later during stance. Running with used shoes produced a higher loading rate of the vertical ground reaction force (+23%, p = 0.016), suggesting higher compressive forces under the heel and placing children at risk to experience impact-related injuries. Nevertheless, the decreased peak ankle and knee power absorption in used shoes (−11%, p = 0.010 and −12%, p = 0.029, respectively) suggests a lower ankle and knee joints loading during the absorption phase that may be beneficial regarding stretch-related injuries.     

The balance control of young children under different shod conditions in a naturalistic environment

BackgroundA primary function of footwear is to protect the feet from environmental conditions and possibly, to reduce the risk of injury. In addition, the use of footwear may be critical to improve the balance control of young children at their early years. Therefore, the objective of this study was to evaluate the performance of different balance tasks in young children under barefoot (unshod) and own covered footwear (shod) conditions.Research questionDoes footwear affect the balance control of young children?MethodsTwenty-three young children (n = 23, M age = 6.32 ± 0.27 years, age range: 5–6 years) participated in this study. Three balance tasks, 1) One-leg stand, 2) Walking heels raised and 3) Jumping on mats were used to determine the balance proficiency of young children.ResultsThe mean scores of the young children were significantly higher with a lower standard deviation under shod condition for the task of walking heels raised.SignificanceThese results suggest that own covered footwear could aid in providing increased postural stability for complex and novel balance tasks which are highly unstable.     

The anatomy and biomechanics of running

To understand the normal series of biomechanical events of running, a comparative assessment to walking is helpful. Closed kinetic chain through the lower extremities, control of the lumbopelvic mechanism, and overall symmetry of movement has been described well enough that deviations from normal movement can now be associated with specific overuse injuries experienced by runners. This information in combination with a history of the runner's errors in their training program will lead to a more comprehensive treatment and prevention plan for related injuries.     

Foot strike pattern in children during shod-unshod running

The purpose of this study was to determine the foot strike patterns (FSPs) and neutral support (no INV/EVE and no foot rotation) in children, as well as to determine the influence of shod/unshod conditions and sex. A total of 713 children, aged 6 to 16 years, participated in this study (Age = 10.28 ± 2.71 years, body mass index [BMI] = 19.70 ± 3.91 kg/m², 302 girls and 411 boys). A sagittal and frontal-plane video (240 Hz) was recorded using a high-speed camcorder, to record the following variables: rearfoot strike (RFS), midfoot strike (MFS), forefoot strike (FFS), inversion/eversion (INV/EVE) and foot rotation on initial contact. RFS prevalence was similar between boys and girls in both shod and unshod conditions. In the unshod condition there was a significant reduction (p < 0.001) of RFS prevalence both in boys (shod condition = 83.95% vs. 62.65% unshod condition) and in girls (shod condition = 87.85% vs. 62.70% unshod condition). No significant differences were found in INV/EVE and foot rotation between sex groups. In the unshod condition there was a significant increase (p < 0.001) of neutral support (no INV/EVE) both in boys (shod condition = 12.55% vs. 22.22% unshod condition) and in girls (shod condition = 17.9% vs. 28.15% unshod condition). In addition, in the unshod condition there is a significant reduction (p < 0.001) of neutral support (no foot rotation) both in boys (shod condition = 21.55% vs. 11.10% unshod condition) and in girls (shod condition = 21.05% vs. 11.95% unshod condition). In children, RFS prevalence is lower than adult’s population. Additionally, barefoot running reduced the prevalence of RFS and INV/EVE, however increased foot rotation.     

The immediate effects of Kinesio Taping on running biomechanics,muscle activity,and perceived changes in comfort,stability and running performance in healthy runners,and the implications to the management of Iliotibial band syndrome

BackgroundKinesio Taping is frequently used in the management of lower limb injuries, and has been shown to improve pain, function, and running performance. However, little is known about the effects of Kinesio Taping on running biomechanics, muscle activity, and perceived benefits.Research questionThis study aimed to explore the immediate effects of Kinesio Taping on lower limb kinematics, joint moments, and muscle activity, as well as perceived comfort, knee joint stability, and running performance in healthy runners.MethodsTwenty healthy participants ran at a self-selected pace along a 20-metre runway under three conditions; no tape (NT), Kinesio Tape with tension (KTT), and Kinesio tape without tension (KTNT). Comparisons of peak hip, knee angles and moments, and EMG were analysed during the stance phase of running.ResultsKTT exhibited significant increases in peak hip flexion, peak hip abduction and hip external rotation compared to NT. Moreover, the KTT condition showed a trend towards a decrease in peak hip internal rotation and adduction angle compared to the NT condition. EMG results showed that Tensor Fascia Latae activity decreased with KTT compared with NT, and Gluteus Maximus activity reduced with KTNT when compared with NT. Ten of the 20 participants indicated important improvements in the comfort score, six participants in the knee stability score, and seven participants in the running performance score when using KTT.SignificanceThese results suggest that changes in running biomechanics previously associated with ITBS can be improved with the application of kinesio tape, with the greatest effect seen with the application of kinesio tape with tension. Perceived improvements were seen in comfort, stability and running performance, however these benefits were only seen in half the participants. Further work is required to explore the biomechanical effects and perceived benefits in different patient groups.     

Effects of treadmill cushion and running speed on plantar force and metabolic energy consumption in running

BackgroundRepetitive loading with high impact forces are considered as a primary risk factor for overuse injuries. Cushion was proposed in running surface and shoe manufacturing to reduce impact forces and prevent injuries in running.Research questionTo investigate the effects of treadmill cushion and running speed on plantar force and metabolic energy consumption in treadmill running.MethodsPlantar force data and metabolic data were collected for 20 men during running at 8 km/h and 10 km/h on the treadmill with and without cushion. Two-way ANOVAs with repeated measures were performed to determine the treadmill effects and the speed effects.ResultsParticipants significantly decreased peak plantar force on the fore foot at both 10 km/h (P = 0.001) and 8 km/h (P = 0.001) and peak plantar force on the mid foot only at 10 km/h (P = 0.011) while running on the treadmill with cushion compared to the treadmill without cushion. The reduction of peak plantar force at 10 km/h was greater than that at 8 km/h while running on the treadmill with cushion. Participants significantly increased metabolic energy consumption while running on the treadmill with cushion compared to the treadmill without cushion (P = 0.007).SignificanceRunning on the treadmill with cushion significantly decreased plantar force on the fore foot and mid foot, and increased metabolic energy consumption. Running on the treadmill with cushion may be a useful method in the prevention of fore foot injuries and increasing exercise effects.     

Investigation of treadmill and overground running: Implications for the measurement of oxygen cost in children with developmental coordination disorder

Differences in the kinematics and kinetics of overground running have been reported between boys with and without developmental coordination disorder (DCD). This study compared the kinematics of overground and treadmill running in children with and without DCD to determine whether any differences in technique are maintained, as this may influence the outcome of laboratory treadmill studies of running economy in this population. Nine boys with DCD (10.3 ± 1.1 year) and 10 typically developing (TD) controls (9.7 ± 1 year) ran on a treadmill and overground at a matched velocity (8.8 ± 0.9 km/h). Kinematic data of the trunk and lower limb were obtained for both conditions using a 12-camera Vicon MX system. Both groups displayed an increase in stance time (p < 0.001), shorter stride length (p < 0.001), higher cadence (p < 0.001) and reduced ankle plantar flexion immediately after toe-off (p < 0.05) when running on the treadmill compared with overground. The DCD group had longer stance time (p < 0.009) and decreased knee flexion at mid-swing (p = 0.04) while running overground compared to their peers, but these differences were maintained when running on the treadmill. Treadmill running improved ankle joint symmetry in the DCD group compared with running overground (p = 0.019). Overall, these findings suggest that there are limited differences in joint kinematics and lower limb symmetry between overground and treadmill running in this population. Accordingly, laboratory studies of treadmill running in children with DCD are likely representative of the energy demands of running.     

A comparison of the spatiotemporal parameters, kinematics, and biomechanics between shod, unshod, and minimally supported running as compared to walking

Recreational running has many proven benefits which include increased cardiovascular, physical and mental health. It is no surprise that Running USA reported over 10 million individuals completed running road races in 2009 not to mention recreational joggers who do not wish to compete in organized events. Unfortunately there are numerous risks associated with running, the most common being musculoskeletal injuries attributed to incorrect shoe choice, training errors and excessive shoe wear or other biomechanical factors associated with ground reaction forces. Approximately 65% of chronic injuries in distance runners are related to routine high mileage, rapid increases in mileage, increased intensity, hills or irregular surface running, and surface firmness. Humans have been running barefooted or wearing minimally supportive footwear such as moccasins or sandals since the beginning of time while modernized running shoes were not invented until the 1970s. However, the current trend is that many runners are moving back to barefoot running or running in “minimal” shoes. The goal of this masterclass article is to examine the similarities and differences between shod and unshod (barefoot or minimally supportive running shoes) runners by examining spatiotemporal parameters, energetics, and biomechanics. These running parameters will be compared and contrasted with walking. The most obvious difference between the walking and running gait cycle is the elimination of the double limb support phase of walking gait in exchange for a float (no limb support) phase. The biggest difference between barefoot and shod runners is at the initial contact phase of gait where the barefoot and minimally supported runner initiates contact with their forefoot or midfoot instead of the rearfoot. As movement science experts, physical therapists are often called upon to assess the gait of a running athlete, their choice of footwear, and training regime. With a clearer understanding of running and its complexities, the physical therapist will be able to better identify faults and create informed treatment plans while rehabilitating patients who are experiencing musculoskeletal injuries due to running.     

Propulsion strategy in running in children and adolescents with cerebral palsy

BackgroundRunning is a fundamental movement skill important for participation in physical activity. Children with cerebral palsy (CP) who are classified at Gross Motor Function Classification Scale (GMFCS) level I and II are able to run but may be limited by neuromuscular impairments.Research questionTo describe the propulsion strategy (PS) during running of children and adolescents with CP.MethodsThis cross-sectional study used kinematic and kinetic data collected during running from 40 children and adolescents with unilateral or bilateral CP and 21 typically developing (TD) children. Maximum speed, peak ankle power generation (A2), peak hip flexor power generation in swing (H3) and PS (PS = A2/(A2 + H3)) were calculated. Linear mixed models were developed to analyze differences between groups.ResultsMaximum speed, A2 and PS were significantly less in children with CP GMFCS level I than in TD children and significantly less in children in GMFCS level II than level I. For children with CP, A2 and PS were significantly smaller in affected legs than non-affected legs. In affected legs, H3 was significantly larger in children in GMFCS level II than GMFCS level I but not different between TD children and children in GFMCS level II.SignificanceThe contribution of ankle plantarflexor power to forward propulsion in running is reduced in young people with CP and is related to GMFCS level. This deficit appears to be compensated in part by increased hip flexor power generation but limits maximum sprinting speed.     

Biomechanics of running with rocker shoes

Objectives

Load reduction is an important consideration in conservative management of tendon overuse injuries such as Achilles tendinopathy. Previous research has shown that the use of rocker shoes can reduce the positive ankle power and plantar flexion moment which might help in unloading the Achilles tendon. Despite this promising implication of rocker shoes, the effects on hip and knee biomechanics remain unclear. Moreover, the effect of wearing rocker shoes on different running strike types is unexplored. The aim of this study was to investigate biomechanics of the ankle, knee and hip joints and the role of strike type on these outcomes.

Leg stiffness during running in highly cushioned shoes with a carbon-fiber plate and traditional shoes

BackgroundNike ZoomX Vaporfly (NVF) improves running economy and performance. The biomechanical mechanisms of these shoes are not fully understood, although thicker midsoles and carbon fiber plates are considered to play an important role in the spring-like leg characteristics during running. Leg stiffness (k_leg) in the spring-mass model has been commonly used to investigate spring-like running mechanics during running.Research questionDoes k_leg during running differ between NVF and traditional (TRAD) shoes?MethodsEighteen male habitual forefoot and/or midfoot strike runners ran on a treadmill at 20 km/h with NVF and TRAD shoes, respectively. k_leg, vertical oscillation of the center of mass (∆CoM), spatiotemporal parameters, and mechanical loading were determined.Resultsk_leg was 4.8% lower in the NVF shoe condition than in the TRAD condition, although no significant difference was observed. ∆CoM was not significantly different between shoe conditions. Spatiotemporal parameters and mechanical loading were also not significantly different between shoe conditions.SignificanceThe NVF shoe is well known as improving the running economy and running performance for the cause by characteristics of better spring function. Contrary to expectation, k_leg and other parameters were not significantly different during running in the NVF compared to TRAD shoe at 20 km/h. These findings indicate that well-trained runners’ spring-like running mechanics would not alter even if wearing the NVF shoes.     

In‐field gait retraining and mobile monitoring to address running biomechanics associated with tibial stress fracture

We sought to determine if an in‐field gait retraining program can reduce excessive impact forces and peak hip adduction without adverse changes in knee joint work during running. Thirty healthy at‐risk runners who exhibited high‐impact forces were randomized to retraining [21.1 (±1.9) years, 22.1 (±10.8) km/week] or control groups [21.0 (±1.3) years, 23.2 (±8.7) km/week]. Retrainers were cued, via a wireless accelerometer, to increase preferred step rate by 7.5% during eight training sessions performed in‐field. Adherence with the prescribed step rate was assessed via mobile monitoring. Three‐dimensional gait analysis was performed at baseline, after retraining, and at 1‐month post‐retraining. Retrainers increased step rate by 8.6% (P < 0.0001), reducing instantaneous vertical load rate (?17.9%, P = 0.003), average vertical load rate (?18.9%, P < 0.0001), peak hip adduction (2.9° ± 4.2 reduction, P = 0.005), eccentric knee joint work per stance phase (?26.9%, P < 0.0001), and per kilometer of running (?21.1%, P < 0.0001). Alterations in gait were maintained at 30 days. In the absence of any feedback, controls maintained their baseline gait parameters. The majority of retrainers were adherent with the prescribed step rate during in‐field runs. Thus, in‐field gait retraining, cueing a modest increase in step rate, was effective at reducing impact forces, peak hip adduction and eccentric knee joint work.     

Effect of slope and footwear on running economy and kinematics

Lower energy cost of running (Cr) has been reported when wearing minimal (MS) vs traditional shoes (TS) on level terrain, but the effect of slope on this difference is unknown. The aim of this study was to compare Cr, physiological, and kinematic variables from running in MS and TS on different slope conditions. Fourteen men (23.4 ± 4.4 years; 177.5 ± 5.2 cm; 69.5 ± 5.3 kg) ran 14 5‐min trials in a randomized sequence at 10 km/h on a treadmill. Subjects ran once wearing MS and once wearing TS on seven slopes, from ?8% to +8%. We found that Cr increased with slope gradient (P < 0.01) and was on average 1.3% lower in MS than TS (P < 0.01). However, slope did not influence the Cr difference between MS and TS. In MS, contact times were lower (P < 0.01), flight times (P = 0.01) and step frequencies (P = 0.02) were greater at most slope gradients, and plantar‐foot angles – and often ankle plantar‐flexion (P = 0.01) – were greater (P < 0.01). The 1.3% difference between footwear identified here most likely stemmed from the difference in shoe mass considering that the Cr difference was independent of slope gradient and that the between‐footwear kinematic alterations with slope provided limited explanations.     

Effects of load carriage and footwear on lower extremity kinetics and kinematics during overground walking

Kinetic and kinematic responses during walking vary by footwear condition. Load carriage also influences gait patterns, but it is unclear how an external load influences barefoot walking. Twelve healthy adults (5 women, 7 men) with no known gait abnormalities participated in this study (age = 23 ± 3 years, height = 1.73 ± 0.11 m, and mass = 70.90 ± 12.67 kg). Ground reaction forces and 3D motion were simultaneously collected during overground walking at 1.5 m s⁻¹ in four conditions: Barefoot Unloaded, Shod Unloaded, Barefoot Loaded, and Shod Loaded. Barefoot walking reduced knee and hip joint ranges of motion, as well as stride length, stance time, swing time, and double support time. Load carriage increased stance and double support times. The 15% body weight load increased GRFs ∼15%. Walking barefoot reduced peak anteroposterior GRFs but not peak vertical GRFs. Load carriage increased hip, knee, and ankle joint moments and powers, while walking barefoot increased knee and hip moments and powers. Thus, spatiotemporal and kinematic adjustments to walking barefoot decrease GRFs but increase knee and hip kinetic measures during overground walking. The ankle seems to be less affected by these footwear conditions. Regardless of footwear, loading requires larger GRFs, joint loads, and joint powers.     

A treadmill test of sprint running

Anaerobic power is characterized by a high degree of specificity regarding both the recruited muscles as well as the recruitment pattern. The popular Wingate Anaerobic Test (WAnT) is a cycling test that does not satisfy the need for a running-specific anaerobic test. We describe such a test, using a novel type of a commercially available treadmill (BRL 1800, Gymrol, France). The ergometer is equipped with a torque motor to neutralize the frictional resistance of the treadmill belt, and a hip-belt harness connected to a horizontal rod. Force applied to the harness is monitored by a strain gauge mounted on the rod, while vertical movement is monitored by a potentiometer at the posterior fixed end of the rod. These, in conjunction with the treadmill belt speed, enable the computation of horizontal and vertical power as well as the combined total output. Power is calculated both as 'peak' power (highest 2.5 s segment) and 'mean' power (20 s duration). Preliminary results of young athletes were generally consistent with the expected age-related changes in anaerobic power. Values obtained on the anaerobic treadmill were always higher than the corresponding WAnT values previously obtained in comparable age groups. The higher values were probably due to the larger muscle mass involved and the shorter peak and mean power durations (2.5 and 20 s versus 5 and 30 s in the WAnT, respectively). This test should enable not only running-specific anaerobic power monitoring but also the characterization of the relationship between the horizontal and vertical components of that power.