Effect of custom-made and prefabricated insoles on plantar loading parameters during running with and without fatigue

Abstract

Controversy exists whether custom-made insoles are more effective in reducing plantar loading compared to prefabricated insoles. Forty recreational athletes ran using custom-made, prefabricated, and the original insoles of their running shoes, at rest and after a fatigue run. Contact time, stride rate, and plantar loading parameters were measured. Neither the insole conditions nor the fatigue state modified contact time and stride rate. Addressing prevention of running injuries, post-fatigue loading values are of great interest. Custom-made insoles reduced the post-fatigue loading under the hallux (92 vs. 130 kPa, P < 0.05), medial midfoot (70 vs. 105 kPa, P < 0.01), and lateral midfoot (62 vs 96 kPa, P < 0.01). Prefabricated insoles provoked reductions in post-fatigue loading under the toes (120 vs. 175 kPa, P < 0.05), medial midfoot (71 vs. 105 kPa, P < 0.01), and lateral midfoot (68 vs. 96 kPa, P < 0.01). Regarding both study insoles, custom-made insoles reduced by 31% and 54% plantar loading under the medial and lateral heel compared to the prefabricated insoles. Finally, fatigue state did not influence plantar loading regardless the insole condition. In long-distance races, even a slight reduction in plantar loading at each foot strike may suppose a significant decrease in the overall stress experienced by the foot, and therefore the use of insoles may be an important protective mechanism for plantar overloading.     

Acute effect of different minimalist shoes on foot strike pattern and kinematics in rearfoot strikers during running

Despite the growing interest in minimalist shoes, no studies have compared the efficacy of different types of minimalist shoe models in reproducing barefoot running patterns and in eliciting biomechanical changes that make them differ from standard cushioned running shoes. The aim of this study was to investigate the acute effects of different footwear models, marketed as “minimalist” by their manufacturer, on running biomechanics. Six running shoes marketed as barefoot/minimalist models, a standard cushioned shoe and the barefoot condition were tested. Foot–/shoe–ground pressure and three-dimensional lower limb kinematics were measured in experienced rearfoot strike runners while they were running at 3.33 m · s^?1 on an instrumented treadmill. Physical and mechanical characteristics of shoes (mass, heel and forefoot sole thickness, shock absorption and flexibility) were measured with laboratory tests. There were significant changes in foot strike pattern (described by the strike index and foot contact angle) and spatio-temporal stride characteristics, whereas only some among the other selected kinematic parameters (i.e. knee angles and hip vertical displacement) changed accordingly. Different types of minimalist footwear models induced different changes. It appears that minimalist footwear with lower heel heights and minimal shock absorption is more effective in replicating barefoot running.     

Primary mechanical factors contributing to foot eversion moment during the stance phase of running

Rearfoot external eversion moments due to ground reaction forces (GRF) during running have been suggested to contribute to overuse running injuries. This study aimed to identify primary factors inducing these rearfoot external eversion moments. Fourteen healthy men ran barefoot across a force plate embedded in the middle of 30-m runway with 3.30 ± 0.17 m · s^–1. Total rearfoot external eversion/inversion moments (Mtot) were broken down into the component Mxy due to medio-lateral GRF (Fxy) and the component Mz due to vertical GRF (Fz). Ankle joint centre height and medio-lateral distance from the centre of pressure to the ankle joint centre (a_cop) were calculated as the moment arm of these moments. Mxy dominated Mtot just after heel contact, with the magnitude strongly dependent on Fxy, which was most likely caused by the medio-lateral foot velocity before heel contact. Mz then became the main generator of Mtot throughout the first half of the stance phase, during which a_cop was the critical factor influencing the magnitude. Medio-lateral foot velocity before heel contact and medio-lateral distance from the centre of pressure to the ankle joint centre throughout the first half of the stance phase were identified as primary factors inducing the rearfoot external eversion moment.     

Energy cost and kinematics of level,uphill and downhill running: fatigue-induced changes after a mountain ultramarathon

This study aimed to determine whether the fatigue induced by a mountain ultramarathon (MUM) led to changes in energy cost and kinematic during level and graded running. Pre- and post-race, 14 ultratrail runners ran on a level, uphill (5%) and downhill (5%) treadmill at 10 km · h^?1. Kinematic data were acquired using a photocell system. Post-race, the downhill energy cost increased by 13.1% (P < 0.001). No change was noted in level and uphill running. Duty factor and stride frequency were increased, whereas swing time, cycle time and stride length were decreased in all conditions (P < 0.05). Contact time was increased and the rate of force generation was decreased only in the uphill and downhill conditions (P < 0.05). Positive correlations were observed between performance time and the pre- to post-changes in the energy cost of level (r = 0.52, P = 0.04) and uphill running (r = 0.50, P = 0.04). MUM-induced fatigue resulted in physiological and spatiotemporal changes, though the response to fatigue varied considerably between running conditions. These changes resulted in a significant increment only in the downhill energy cost. Incorporating downhill locomotion in the training programmes of ultratrailers may help to improve performance-related physiological and biomechanical parameters.     

Differential effects of speed on two-dimensional foot strike pattern during barefoot and shod running in recreationally active men

ABSTRACT

The majority of barefoot running studies have not considered speed as an influential factor on foot strike pattern. The aim of this study was to investigate differences in foot strike pattern and spatiotemporal characteristics between barefoot and shod overground running at varying speeds. We first determined maximal running speed (Vm) over 50 m in 15 recreationally active men who self-reported as habitual rearfoot strikers. Participants then completed shod and barefoot running trials at different speeds equivalent to approximately 90%, 80%, 70% and 60% of Vm. Sagittal plane two-dimensional (2D) foot-ground contact angle, ankle plantar-dorsi flexion angle, contact time, flight time, step length and step rate variables for each trial were recorded. A significant interaction effect of running speed and footwear condition (p < 0.05) on foot-ground contact angle, ankle plantar-dorsi flexion angle and contact time was observed. There was a main effect of running speed (p < 0.01) on flight time, step length and step rate. There was a main effect of footwear condition on step length (p < 0.01). Participants were more inclined to plantarflex the ankle and contact the ground with the forefoot at higher percentages of Vm, especially when running barefoot.     

Validity of a trunk-mounted accelerometer to assess peak accelerations during walking,jogging and running

Abstract

The purpose of this study was to validate peak acceleration data from an accelerometer contained within a wearable tracking device while walking, jogging and running. Thirty-nine participants walked, jogged and ran on a treadmill while 10 peak accelerations per movement were obtained (n = 390). A single triaxial accelerometer measured resultant acceleration during all movements. To provide a criterion measure of acceleration, a 12-camera motion analysis (MA) system tracked the position of a retro-reflective marker affixed to the wearable tracking device. Peak raw acceleration recorded by the accelerometer significantly overestimated peak MA acceleration (P < 0.01). Filtering accelerometer data improved the relationship with the MA system (P < 0.01). However, only the 10 Hz and 8 Hz cut-off frequencies significantly reduced the errors found. The walk movement demonstrated the highest accuracy, agreement and precision and the lowest relative errors. Linear increases in error were observed for jog compared with walk and for run compared to both other movements. As the magnitude of acceleration increased, the strength of the relationship between the accelerometer and the criterion measure decreased. These results indicate that filtered accelerometer data provide an acceptable means of assessing peak accelerations, in particular for walking and jogging.     

Between-limb differences in running technique induces asymmetric negative joint work during running

Negative work, which is mainly generated by eccentric muscle contraction, has an important influence on the associated muscle damage. Generally, mechanical parameters are determined for one side of a lower extremity on the assumption of negligible between-limb differences. However, between-limb differences in the negative work of lower extremity joints during running remain unclear. This study examines between-limb differences in negative work and associated mechanical parameters during the contact phase of running. Twenty-five young adult males voluntarily participated in this study. Each participant was asked to run on a straight runway at a speed of 3.0?m?s^?1. Negative work, amplitude, duration of negative power, moment, and angular velocity were computed for both sides of the lower extremities. Significant differences were found in negative work between limbs for the hip (18.9?±?11.7%), knee (13.6?±?10.4%), and ankle (11.8?±?8.5%) joints. For the hip joint, asymmetric negative work was attributable to the between-limb difference in the amplitude of negative power owing to a corresponding difference in the moment. The between-limb differences concerning the duration and amplitude of negative power could explain the asymmetric negative work in the knee joint. The asymmetric negative work of the ankle joint was attributable to the between-limb difference in the amplitude and duration of the negative power and the moment. These results indicate that asymmetric negative work was generated in each lower extremity joint; however, the major mechanical parameters corresponding to the negative work are not the same across the joints.     

Caution using data from triaxial accelerometers housed in player tracking units during running

Usage of accelerometers within player tracking devices in sport to quantify load, vertical ground reaction force (vGRF) or energy expenditure is contrary to placement guidelines. This study aimed to determine whether trunk-mounted accelerometers were a valid and reliable method to estimate thoracic segment or centre of gravity (COG) acceleration or vGRF, and the whether the elasticised harness contributes to the overestimation of acceleration. Ten male amateur rugby players performed five linear running tasks per lower limb at three speeds, twice, each with a different player tracking unit. Three-dimensional data were recorded and triaxial accelerometers were attached lateral to the device on the harness and skin and both shanks. Accelerometers demonstrated poor reliability (ICC:0.0–0.67), high variability (CV%:14–33%) and change in mean (41–160%), and were not valid to estimate vertical acceleration of the COG and thoracic segment nor vGRF. Caution is advised when utilising trunk-mounted triaxial accelerometer data as it is not a valid or reliable means to estimate peak vertical acceleration for its thoracic location nor whole-body COG acceleration or vGRF during running. To improve player tracking instrument validity and reliability, a new attachment method and/or harness material(s), that reduce or eliminate extraneous acceleration during running, are urgently required.     

The effect of three surface conditions,speed and running experience on vertical acceleration of the tibia during running*

Research has focused on parameters that are associated with injury risk, e.g. vertical acceleration. These parameters can be influenced by running on different surfaces or at different running speeds, but the relationship between them is not completely clear. Understanding the relationship may result in training guidelines to reduce the injury risk. In this study, thirty-five participants with three different levels of running experience were recruited. Participants ran on three different surfaces (concrete, synthetic running track, and woodchip trail) at two different running speeds: a self-selected comfortable speed and a fixed speed of 3.06 m/s. Vertical acceleration of the lower leg was measured with an accelerometer. The vertical acceleration was significantly lower during running on the woodchip trail in comparison with the synthetic running track and the concrete, and significantly lower during running at lower speed in comparison with during running at higher speed on all surfaces. No significant differences in vertical acceleration were found between the three groups of runners at fixed speed. Higher self-selected speed due to higher performance level also did not result in higher vertical acceleration. These results may show that running on a woodchip trail and slowing down could reduce the injury risk at the tibia.     

Understanding the influence of perceived fatigue on coordination during endurance running

ABSTRACT

During the course of a training programme, runners will typically increase running velocity and volume possibly encountering fatigue during a run, which is characterised as a feeling of general tiredness. The purpose of the current study was to identify whether or not level of perceived fatigue affects coordination and coordination variability in healthy runners during the recovery velocity of an endurance interval run. A total of 20 endurance runners completed a 1-hour run that included running velocity intervals at 75% of estimated 10 k race pace (5 minutes) and estimated 10 k race pace (1 minute). After each run, participants completed a fatigue questionnaire and were grouped based on their post-run self-reported perceived fatigue. 3D motion capture data were collected during the run and analysed to generate coordination patterns and variability of the patterns as dependent variables. Multiple mixed model ANOVAs were conducted to test for differences between perceived fatigue groups. Coordination and variability differences were reported in a number of couplings during transition phases (late and early stance) and events (toe-off and foot contact) of the gait cycle. It was concluded that the level of perceived fatigue affected coordination and coordination variability during the recovery velocity of a 1-hour interval run.     

Measurement of intrinsic foot stiffness in minimally and traditionally shod runners using ultrasound elastography: A pilot study

ABSTRACT

Running is an activity with a consistently high injury rate. Running footwear design that mimics barefoot running has been proposed to reduce injury rate by increasing the strength of foot structures. However, there is little evidence to support this. The purpose of the current study is to use shear wave ultrasound elastography to examine material properties (shear modulus) of intrinsic foot structures in experienced minimally and traditionally shod runners. It is hypothesized that minimalist runners will exhibit increased stiffness compared to controls demonstrating the strengthening of these structures. Eighteen healthy runners (8 minimalist and 10 traditionalist), running a minimum of 10 mi · wk^?1, participated. Elastography scans were performed on the left foot of each participant. There is no apparent stiffening of foot structures associated with wearing minimalist shoes. Only the FHB tendon is different between shoe types and, contrary to the hypothesis, was stiffer in traditionalist compared to minimalist runners (257.26 ± 51.64 kPa vs 160.88 ± 27.79 kPa, respectively). A moderate positive (r = 0.7) relationship between training load and tendon stiffness suggests strengthening of tendon when running in traditional shoes. If running in minimalist shoes increases loading on these structures without resulting in stronger tissues, it is possible that minimalist footwear may increase injury risk.     

Mechanics of the muscles crossing the hip joint during sprint running

Abstract

We aimed to demonstrate the changes over time in the lengths and forces of the muscles crossing the hip joint during overground sprinting and investigate the relationships between muscle lengths and muscle–tendon unit forces – particularly peak biceps femoris force. We obtained three-dimensional kinematics during 1 running cycle from 8 healthy sprinters sprinting at maximum speed. Muscle lengths and muscle–tendon unit forces were calculated for the iliacus, rectus femoris, gluteus maximus, and biceps femoris muscles of the target leg as well as the contralateral iliacus and rectus femoris. Our results showed that during sprinting, the muscles crossing the hip joint demonstrate a stretch-shortening cycle and 1 or 2 peak forces. The timing of peak biceps femoris force, expressed as a percentage of the running cycle (mean [SD], 80.5 [2.9]%), was synchronous with those of the maximum biceps femoris length (82.8 [1.9]%) and peak forces of the gluteus maximus (83.8 [9.1]%), iliacus (81.1 [5.2]%), and contralateral iliacus (78.5 [5.8]%) and also that of the peak pelvic anterior tilt. The force of the biceps femoris appeared to be influenced by the actions of the muscles crossing the hip joint as well as by the pelvic anterior tilt.     

Kinetic and kinematic analysis of stamping impacts during simulated rucking in rugby union

Laceration injuries account for up to 23% of injuries in rugby union. They are frequently caused by studded footwear as a result of a player stamping onto another player during the ruck. Little is known about the kinetics and kinematics of rugby stamping impacts; current test methods assessing laceration injury risk of stud designs therefore lack informed test parameters. In this study, twelve participants stamped on an anthropomorphic test device in a one-on-one simulated ruck setting. Velocity and inclination angle of the foot prior to impact was determined from high-speed video footage. Total stamping force and individual stud force were measured using pressure sensors. Mean foot inbound velocity was 4.3 m ? s^?1 (range 2.1–6.3 m ? s^?1). Mean peak total force was 1246 N and mean peak stud force was 214 N. The total mean effective mass during stamping was 6.6 kg (range: 1.6–13.5 kg) and stud effective mass was 1.2 kg (range: 0.5–2.9 kg). These results provide representative test parameters for mechanical test devices designed to assess laceration injury risk of studded footwear for rugby union.     

Muscle coordination,activation and kinematics of world-class and elite breaststroke swimmers during submaximal and maximal efforts

The aims of this study were to describe muscular activation patterns and kinematic variables during the complete stroke cycle (SC) and the different phases of breaststroke swimming at submaximal and maximal efforts. Surface electromyography (sEMG) was collected from eight muscles in nine elite swimmers; five females (age 20.3 ± 5.4 years; Fédération Internationale de Natation [FINA] points 815 ± 160) and four males (27.7 ± 7.1 years; FINA points 879 ± 151). Underwater cameras were used for 3D kinematic analysis with automatic motion tracking. The participants swam 25 m of breaststroke at 60%, 80% and 100% effort and each SC was divided into three phases: knee extension, knee extended and knee flexion. With increasing effort, the swimmers decreased their SC distance and increased their velocity and stroke rate. A decrease during the different phases was found for duration during knee extended and knee flexion, distance during knee extended and knee angle at the beginning of knee extension with increasing effort. Velocity increased for all phases. The mean activation pattern remained similar across the different effort levels, but the muscles showed longer activation periods relative to the SC and increased integrated sEMG (except trapezius) with increasing effort. The muscle activation patterns, muscular participation and kinematics assessed in this study with elite breaststroke swimmers contribute to a better understanding of the stroke and what occurs at different effort levels. This could be used as a reference for optimising breaststroke training to improve performance.     

体育学院办学的社会化展望

采用调查、实验、逻辑推理等方法，探索体育院校办学的途径，结果证明：依托行业，面向社会，多方协作，共同办学的大教育观是可行的。     

划船式短跑途中跑技术上肢动作描述及其数据证明

本文引用相关数据证明以下“划船式短跑途中跑技术[1]”是世界级水平部分运动员使用的技术;而低于世界级水平部分优秀运动员使用的是经典短跑途中跑技术。     

Modelling error distribution in the ground reaction force during an induced-acceleration analysis of running in rear-foot strikers

The objective of this study was to develop and evaluate a methodology for quantifying the contributions of modelling error terms, as well as individual joint torque, gravitational force and motion-dependent terms, to the generation of ground reaction force (GRF), whose true value can be measured with high accuracy using a force platform. Dynamic contributions to the GRF were derived from the combination of (1) the equations of motion for the individual segments, (2) the equations for constraint conditions arising from the connection of adjacent segments at joints, and (3) the equations for anatomical constraint axes at certain joints. The contribution of the error term was divided into four components caused by fluctuation of segment lengths, geometric variation in the constraint joint axes, and residual joint force and moment errors. The proposed methodology was applied to the running motion of thirteen rear-foot strikers at a constant speed of 3.3?m/s. Modelling errors arose primarily from fluctuations in support leg segment lengths and rapid movement of the virtual joint between the foot and ground during the first 20% of stance phase. The magnitudes of these error contributions to the vertical and anterior/posterior components of the GRF are presented alongside the non-error contributions, of which the joint torque term was the largest.     

Effects of intense exercise on the physiological and mental condition of female university judoists during a training camp

Abstract

To clarify the physical and mental fatigue caused by intense exercise and the relationship between the two types of fatigue, we examined changes in anthropometric and biochemical variables, neutrophil function, and the Profile of Mood States (POMS) questionnaire in 13 female university judoists attending a one-week training camp. Blood glucose, total cholesterol, haemoglobin, leukocyte count, IgG, and phagocytic activity all decreased after the training camp compared with baseline (P ≤ 0.046). Aspartate aminotransferase, lactate dehydrogenase, creatine kinase, and neutrophil oxidative burst activity increased after the training camp (P ≤ 0.007). Of the POMS scores, that for Fatigue increased after the training camp (P = 0.041) and that for Vigour decreased (P = 0.042). The changes in several POMS scores correlated with the changes in blood biochemical variables. In particular, the change in Total mood disturbance was negatively associated with changes in myogenic enzymes (P ≤ 0.032). Our results suggest that intense exercise during training camps for female judoists leads to the appearance and accumulation of mental and physical fatigue, which are related to each other.     

Gait Characteristics Over the Course of a Race in Recreational Marathon Competitors

We analyzed gait and function of the supporting limb in participants of a marathon race at three stages: prerace, midrace (18 km), and near the end of the race (36 km). We confirmed that the most successful runners were able to maintain running speed for the duration of the race with little change in speed or gait. Speed slowed progressively during the race for those with slower race times, but stride frequency–stride length relationships remained normal for the speed they ran. These findings differ from most lab-based studies of fatigue, in which runners are forced to match a constant preset treadmill speed. Small changes in maximum ground force were seen in both slow- and fast-running participants as race end approached.     

对短跑运动员途中跑踝关节技术的研究

通过对短跑运动员途中跑踝关节技术的比较研究，探讨了踝关节技术与屈蹬技术的关系，以及踝关节技术对运动员途中跑中各项技术指标产生的影响。研究认为：背屈踝前摆腿技术要优于放松踝的前摆腿技术。主要表现在有利于屈蹬技术的形成，蹬地更有力，支撑时间更短，步频更快。