The biomechanical variables involved in the aetiology of iliotibial band syndrome in distance runners – A systematic review of the literature

The aim of this literature review was to identify the biomechanical variables involved in the aetiology of iliotibial band syndrome (ITBS) in distance runners. An electronic search was conducted using the terms “iliotibial band” and “iliotibial tract”.The results showed that runners with a history of ITBS appear to display decreased rear foot eversion, tibial internal rotation and hip adduction angles at heel strike while having greater maximum internal rotation angles at the knee and decreased total abduction and adduction range of motion at the hip during stance phase. They further appear to experience greater invertor moments at their feet, decreased abduction and flexion velocities at their hips and to reach maximum hip flexion angles earlier than healthy controls. Maximum normalised braking forces seem to be decreased in these athletes. The literature is inconclusive with regards to muscle strength deficits in runners with a history of ITBS. Prospective research suggested that greater internal rotation at the knee joint and increased adduction angles of the hip may play a role in the aetiology of ITBS and that the strain rate in the iliotibial bands of these runners may be increased compared to healthy controls.A clear biomechanical cause for ITBS could not be devised due to the lack of prospective research.     

Kinematic classification of iliotibial band syndrome in runners

Several inconsistent causative biomechanical factors are considered to be crucial in the occurrence of iliotibial band syndrome (ITBS). The focus of this study was on assessing differences in the kinematic characteristics between healthy runners [control group (CO)] and runners with ITBS in order to recommend treatment strategies to deal with this injury. Three‐dimensional kinematics of barefoot running was used in the biomechanical setup. Both groups were matched with respect to gender, height and weight. After determining drop outs, the final population comprised 36 subjects (26 male and 10 female): 18 CO and 18 ITBS (13 male and five female, each). Kinematic evaluations indicate less hip adduction and frontal range of motion at the hip joint in runners with ITBS. Furthermore, maximum hip flexion velocity and maximum knee flexion velocity were lower in runners with ITBS. Lack of joint coordination, expressed as earlier hip flexion and a tendency toward earlier knee flexion, was found to be another discriminating variable in subjects with ITBS compared with CO subjects. We assume that an increase in range of motion at the hip joint, stretching of the hip abductors, as well as stretching the hamstrings, calf muscles and hip flexors will help treat ITBS.     

Gender differences in gait kinematics in runners with iliotibial band syndrome

Atypical running gait biomechanics are considered a primary factor in the etiology of iliotibial band syndrome (ITBS). However, a general consensus on the underpinning kinematic differences between runners with and without ITBS is yet to be reached. This lack of consensus may be due in part to three issues: gender differences in gait mechanics, the preselection of discrete biomechanical variables, and/or relatively small sample sizes. Therefore, this study was designed to address two purposes: (a) examining differences in gait kinematics for male and female runners experiencing ITBS at the time of testing and (b) assessing differences in gait kinematics between healthy gender‐ and age‐matched runners as compared with their ITBS counterparts using waveform analysis. Ninety‐six runners participated in this study: 48 ITBS and 48 healthy runners. The results show that female ITBS runners exhibited significantly greater hip external rotation compared with male ITBS and female healthy runners. On the contrary, male ITBS runners exhibited significantly greater ankle internal rotation compared with healthy males. These results suggest that care should be taken to account for gender when investigating the biomechanical etiology of ITBS.     

Kinematic risk factors for lower limb tendinopathy in distance runners: A systematic review and meta-analysis

IntroductionAbnormal kinematics have been implicated as one of the major risk factors for lower limb tendinopathy (LLT).ObjectiveTo systematically review evidence for kinematic risk factors for LLT in runners.MethodsIndividual electronic searches in PubMed, EMBASE and Web of Science were conducted. Two reviewers screened studies to identify observational studies reporting kinematic risk factors in runners with LLT compared to healthy controls. The Down and Black appraisal scale was applied to assess quality. A meta-analysis was performed provided that at least two studies with similar methodology reported the same factor.ResultsTwenty-eight studies were included: Achilles tendinopathy (AT) (9), iliotibial band syndrome (ITBS) (17), plantar fasciopathy (PF) (2), patellar tendinopathy (PT) (1), posterior tibial tendon dysfunction (PTTD) (1). Eighteen studies were rated high-quality and ten medium-quality. The meta-analyses revealed strong evidence of higher peak knee internal rotation, moderate evidence of lower peak rearfoot eversion and knee flexion at heel strike and greater peak hip adduction in runners with ITBS. Very limited evidence revealed higher peak ankle eversion in runners with PF and PTTD or higher peak hip adduction in PT.SignificancePeak rearfoot eversion was the only factor reported in all included LLTs; it is a significant factor in ITBS, PT and PTTD but not in AT and PF. More prospective studies are needed to accurately evaluate the role of kinematic risk factors as a cause of LLT. Taken together, addressing rearfoot kinematic and kinematic chain movements accompanied by peak eversion should be considered in the prevention and management of LLT.     

Stiffness of the iliotibial band and associated muscles in runner’s knee: Assessing the effects of physiotherapy through ultrasound shear wave elastography

ObjectivesTo test the hypothesis that Iliotibial Band Syndrome (ITBS) is caused by excessive iliotibial band (ITB) tension, promoted by hip abductor and external rotator weakness, and evaluate the influence of 6 weeks of physiotherapy on ITB stiffness.DesignInterventional study with control group.SettingClinical.Participants14 recreational runners with ITBS and 14 healthy controls of both sexes.Main outcome measuresUltrasound shear wave elastography, hip muscle strength, visual analog scale pain, subjective lower extremity function.ResultsNo statistical differences in ITB tension between legs as well as between patients suffering from ITBS and healthy controls were detected. Results showed significant strength deficits in hip abduction, adduction as well as external and internal rotation. Following six weeks of physiotherapy, hip muscle strength (all directions but abduction), pain and lower extremity function were significantly improved. ITB stiffness, however, was found to be increased compared to baseline measurements.ConclusionShear wave elastography data suggest that ITB tension is not increased in the affected legs of runners with ITBS compared to the healthy leg or a physical active control group, respectively. Current approaches to the conservative management of ITBS appear ineffective in lowering ITB tone.     

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

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

Walking kinematics in individuals with patellofemoral pain syndrome: a case-control study

Patellofemoral pain syndrome (PFPS) development is considered to be multifactorial with various knee, hip and foot/ankle kinematic factors thought to be involved. A paucity of research evaluating kinematic factors throughout the lower limb kinematic chain simultaneously in individuals with PFPS was identified in a recent systematic review. The objective of this study was to compare kinematics at the knee, hip and foot/ankle in a group of individuals with PFPS to a group of asymptomatic controls. Twenty-six individuals with PFPS and 20 controls aged between 18 and 35 were recruited. Between-group comparisons were made for magnitude and timing of peak angles, and range of motion at the forefoot (dorsiflexion, abduction and supination), rearfoot (dorsiflexion, internal rotation and eversion), knee (flexion, abduction and internal rotation) and hip (adduction and internal rotation) during walking. The PFPS group demonstrated less peak hip internal rotation (7.0° versus 11.8°, p=0.024, p=0.024), earlier peak rearfoot eversion relative to the laboratory (30.4% versus 35.3% of the gait cycle, p=0.010) and tibia (32.7% versus 36.5% of the gait cycle, p=0.030), and greater rearfoot dorsiflexion range of motion relative to the laboratory (72.3° versus 68.2°, p=0.007). Additionally, a trend toward reduced gait velocity (p=0.070) was found in the PFPS group. Reduced peak hip internal rotation and gait velocity in individuals with PFPS may indicate compensation to reduce PFJ load during walking. However, earlier peak rearfoot eversion may be a factor related to the pathomechanical development of the condition.     

DOMS-associated changes in ankle and knee joint dynamics during running

PURPOSE: The purpose of this study was to determine whether leg mechanics change due to DOMS by examining ankle and knee joint kinematics and stiffness before and after a down hill run. METHODS: Sagittal plane kinematics were recorded with high-speed (120 Hz) video at a speed representing 75% of VO2peak of nine well-trained male runners before (RE1) and 48 h after (RE2) a 30-min downhill run. From the recorded video, 10-12 consecutive strides were digitized, and the following variables were calculated for each stride: ankle and knee range of motion (ROM), ankle and knee peak angular velocity, ankle and knee stiffness, and leg vertical stiffness. A repeated measures ANOVA was calculated for each variable (alpha = 0.05). RESULTS: Both knee and ankle ROM during stance decreased with DOMS, but otherwise there were few changes in ankle mechanics with DOMS. Knee stiffness tended to increase during the early portion of stance (from initial stance to maximum angular velocity of flexion) with DOMS, immediately followed by a decrease (to maximum knee flexion) in stiffness. Changes in knee stiffness caused vertical leg stiffness to increase for the initial portion of stance with DOMS. CONCLUSION: Knee mechanics changed such that the knee stiffness increased at initial stance, resulting in an increase in vertical leg stiffness. This change in knee stiffness possibly serves as a protective mechanism to prevent further damage or pain in the knee extensor musculature.     

Iliotibial band syndrome: an examination of the evidence behind a number of treatment options

Iliotibial band (ITB) syndrome (ITBS) is a common cause of distal lateral thigh pain in athletes. Treatment often focuses on stretching the ITB and treating local inflammation at the lateral femoral condyle (LFC). We examine the area's anatomical and biomechanical properties. Anatomical studies of the ITB of 20 embalmed cadavers. The strain generated in the ITB by three typical stretching maneuvers (Ober test; Hip flexion, adduction and external rotation, with added knee flexion and straight leg raise to 30°) was measured in five unembalmed cadavers using strain gauges. Displacement of the Tensae Fasciae Latae (TFL)/ITB junction was measured on 20 subjects during isometric hip abduction. The ITB was uniformly a lateral thickening of the circumferential fascia lata, firmly attached along the linea aspera (femur) from greater trochanter up to and including the LFC. The microstrain values [median (IQR)] for the OBER [15.4(5.1–23.3)me], HIP [21.1(15.6–44.6)me] and SLR [9.4(5.1–10.7)me] showed marked disparity in the optimal inter‐limb stretching protocol. HIP stretch invoked significantly (Z=2.10, P=0.036) greater strain than the SLR. TFL/ITB junction displacement was 2.0±1.6 mm and mean ITB lengthening was <0.5% (effect size=0.04). Our results challenge the reasoning behind a number of accepted means of treating ITBS. Future research must focus on stretching and lengthening the muscular component of the ITB/TFL complex.     

Effects of medially wedged insoles on the biomechanics of the lower limbs of runners with excessive foot pronation and foot varus alignment

BackgroundExcessive foot pronation during running in individuals with foot varus alignment may be reduced by medially wedged insoles.Research questionThis study investigated the effects of a medially wedged insole at the forefoot and at the rearfoot on the lower limbs angles and internal moments of runners with excessive foot pronation and foot varus alignment.MethodsKinematic and kinetic data of 19 runners (11 females and 8 males) were collected while they ran wearing flat (control condition) and medially wedged insoles (insole condition). Both insoles had arch support. We used principal component analysis for data reduction and dependent t-test to compare differences between conditions.ResultsThe insole condition reduced ankle eversion (p = 0.003; effect size = 0.63); reduced knee range of motion in the transverse plane (p = 0.012; effect size = 0.55); increased knee range of motion in the frontal plane in early stance and had earlier knee adduction peak (p = 0.018; effect size = 0.52); reduced hip range of motion in the transverse plane (p = 0.031; effect size = 0.48); reduced hip adduction (p = 0.024; effect size = 0.50); reduced ankle inversion moment (p = 0.012; effect size = 0.55); and increased the difference between the knee internal rotation moment in early stance and midstance (p = 0.012; effect size = 0.55).SignificanceInsoles with 7˚ medial wedges at the forefoot and rearfoot are able to modify motion and moments patterns that are related to lower limb injuries in runners with increased foot pronation and foot varus alignment with some non-desired effects on the knee motion in the frontal plane.     

Iliotibial band syndrome in runners: innovations in treatment

Iliotibial band syndrome (ITBS) is the most common cause of lateral knee pain in runners. It is an overuse injury that results from repetitive friction of the iliotibial band (ITB) over the lateral femoral epicondyle, with biomechanical studies demonstrating a maximal zone of impingement at approximately 30 degrees of knee flexion. Training factors related to this injury include excessive running in the same direction on a track, greater-than-normal weekly mileage and downhill running. Studies have also demonstrated that weakness or inhibition of the lateral gluteal muscles is a causative factor in this injury. When these muscles do not fire properly throughout the support phase of the running cycle, there is a decreased ability to stabilise the pelvis and eccentrically control femoral abduction. As a result, other muscles must compensate, often leading to excessive soft tissue tightness and myofascial restrictions. Initial treatment should focus on activity modification, therapeutic modalities to decrease local inflammation, nonsteroidal anti-inflammatory medication, and in severe cases, a corticosteroid injection. Stretching exercises can be started once acute inflammation is under control. Identifying and eliminating myofascial restrictions complement the therapy programme and should precede strengthening and muscle re-education. Strengthening exercises should emphasise eccentric muscle contractions, triplanar motions and integrated movement patterns. With this comprehensive treatment approach, most patients will fully recover by 6 weeks. Interestingly, biomechanical studies have shown that faster-paced running is less likely to aggravate ITBS and faster strides are initially recommended over a slower jogging pace. Over time, gradual increases in distance and frequency are permitted. In the rare refractory case, surgery may be required. The most common procedure is releasing or lengthening the posterior aspect of the ITB at the location of peak tension over the lateral femoral condyle.     

The effects of marathon running on three-dimensional knee kinematics during walking and running in recreational runners

BackgroundRunning-related musculoskeletal injuries are common. Knee injuries are most frequent, and often occur during or shortly after marathons.Research questionThe effects of a marathon on runners’ knee kinematics remain unclear. No studies have shown comprehensive three-dimensional (3D) knee kinematic changes following a marathon. This study aimed to observe the effects of running a marathon on 3D knee kinematics and identify the phases of walking and running gait in which significant changes occur.MethodsBased on an electronic survey, 10 healthy, recreational runners (20 knees) with similar running experience were included. Their 3D knee kinematics (during treadmill walking and running) were collected using a portable, optical motion capture system within 24 h before and within 6 h after running a marathon.ResultsAll measurements after the marathon were compared with pre-marathon measurements. (1) For walking post-marathon: varus rotation increased by 1.8° [95% confidence interval (CI) 0.1–3.4, P = 0.036] at peak knee extension during stance; anterior translation increased by 2.2 mm (95% CI 0.3–4.1, P = 0.025) at initial contact; range of motion (ROM) in internal-external rotation increased less than 1°, P = 0.023; ROM in anteroposterior translation increased by 3.8 mm, P = 0.048. (2) For running post-marathon: flexion rotation increased by 1.6° (95% CI 0.2–2.9, P = 0.025) at initial contact; varus rotation increased by 2.0° (95% CI 0.2–3.8, P = 0.031) at peak knee extension during stance.SignificanceSignificant differences in varus rotation and anterior translation were identified following a marathon, which could potentially contribute to injury. These results provide important information for runners and coaches about knee kinematic alterations following a marathon.     

Lower extremity kinematics and kinetics of Division III collegiate baseball and softball players while performing a modified pro-agility task

AIM: Females experience at least twice as many non-contact anterior cruciate ligament (ACL) injuries as males. The aim of this study was to investigate if males and females exhibited different characteristics while performing a modified pro-agility test. METHODS: Collegiate Division III male baseball (n=14) and female softball (n=13) players performed 4 trials of a modified pro-agility task, which consisted of running toward a force platform target for 5 steps, planting their right foot, and propelling themselves off of the target with their left foot. Kinematic and kinetic parameters were compared using a multivariate analysis of variance between gender with the level of significance set at P<0.05. RESULTS: Males and females exhibited similar knee valgus angles. Females had a greater maximum knee extension angle (10.14 degrees vs 17.43 degrees ), and greater knee range of motion (46.12 degrees vs 40.12 degrees ). Both groups reached maximum knee flexion at 52% of stance. Females had significantly more maximum hip flexion than males (28.86 degrees vs 22.75 degrees ). Females had significantly smaller minimum internal knee varus moments than their male counterparts (1.12 Nm/kg vs 1.55 Nm/kg). Vertical ground reaction forces as a percentage of bodyweight, and stance time, were not statistically different. The female group displayed an external knee rotation angle (2.49 degrees ) during the beginning of their stance, which was significantly different than the internal rotation angle (4.11 degrees ) in the male group. Early in stance knee rotation angle was highly correlated with the lack of internal knee varus moment (males R(2)=0.75, females R(2)=0.88). CONCLUSION: Females displayed knee moments and kinematics that may place them at greater risk for ACL injury during a stop-cut task. Females should be coached to perform stop cuts with more knee flexion and a more neutral knee rotation angle upon foot contact in an effort to reduce moments that may place the ACL at risk.     

High-arched runners exhibit increased leg stiffness compared to low-arched runners

Leg stiffness between high-arched (HA) and low-arched (LA) runners was compared. It was hypothesized that high-arched runners would exhibit increased leg stiffness, increased sagittal plane support moment, greater vertical loading rates, decreased knee flexion excursion and increased activation of the knee extensor musculature. Twenty high-arched and 20 low-arched subjects were included in this study. Leg stiffness, knee stiffness, vertical loading rate and lower extremity support moment were compared between groups. Electromyographic data were collected in an attempt to explain differences in leg stiffness between groups. High-arched subjects were found to have increased leg stiffness and vertical loading rate compared to low-arched runners. Support moment at the impact peak of the vertical ground reaction force was related to leg stiffness across all subjects. High-arched subjects demonstrated decreased knee flexion excursion during stance. Finally, high-arched subjects exhibited a significantly earlier onset of the vastus lateralis (VL) than the low-arched runners. Differences exist in leg stiffness and vertical loading rate between runners with different foot types. Differences in lower extremity kinetics in individuals with different foot types may have implications for new treatment strategies or preventative measures.     

Effect of altered sagittal-plane knee kinematics on loading during the early stance phase of gait

BackgroundIndividuals with knee osteoarthritis (OA) show various dynamic sagittal-plane changes during the early stance phase of gait. However, the effect of these kinematic alterations on knee load during the early stance remains poorly understood. Research question: The purpose of this study was to examine the effect of altered sagittal- plane knee kinematics on knee load during the early stance.MethodsA total of 13 healthy adult men underwent gait analysis trials using four conditions (baseline and three altered conditions). The three altered conditions were defined as follows:1) Less flexion (LF): a gait that decreased knee flexion excursion (KFE) owing to a reduced peak knee flexion angle compared to baseline.2) Initial flexion (IF): a gait with decreased KFE owing to an increased knee flexion angle at initial contact, during which the peak knee flexion angle did not differ from baseline.3) Flexion gait (FG): a gait that increased the knee flexion angle at initial contact but did not reduce KFE compared with the baseline.Data analyzed included peak external knee flexion moment (KFM), KFM impulse (impulse was an integral value from initial contact to peak value), peak vertical ground reaction force (VGRF), and maximum loading rate.ResultsBoth LF and IF conditions significantly decreased peak VGRF (p < 0.05) compared with the baseline. Peak KFM decreased in the LF condition and increased in the FG condition versus baseline (p < 0.05). A significantly increased KFM impulse was found in both IF and FG conditions when compared with baseline (p < 0.05).SignificanceAn increase in knee flexion angle during early stance increased knee loading. Interventions are likely required for improving excessive knee flexion during early stance phase of gait in individuals with knee OA.     

Relationship between iliotibial band syndrome and hip neuromechanics in women runners

BackgroundAtypical frontal plane hip kinematics are associated with iliotibial band syndrome in women runners. Gluteus medius is the primary muscle controlling the hip adduction angle during the loading response of stance. It is unclear if differences exist in gluteus medius activity magnitude and activity duration between runners with previous iliotibial band syndrome and controls. Furthermore, hip neuromechanics may change after a prolonged run.Research QuestionDo differences exist in the hip adduction angle and gluteus medius activity between women with previous iliotibial band syndrome and controls at the beginning and end of a 30-minute moderate paced treadmill run?MethodsThirty women participated (n = 15 controls). Lower extremity kinematics and gluteus medius activity were recorded at the start and end of a 30-minute treadmill run at participants’ self-selected pace. Hip kinematics and gluteus medius activity were analyzed via separate two-way (group x time) mixed-model analysis of variance with time as the repeated measure.ResultsHip neuromechanics were similar at the start and end of a 30-minute treadmill run in women with previous iliotibial band syndrome and controls. However, hip adduction excursion was less in women with previous iliotibial band syndrome compared to controls. Average gluteus medius activity magnitude and activity duration were not significantly different between groups.SignificanceThese findings support the growing body of literature that smaller hip adduction motion is related to previous iliotibial band syndrome in women. Regardless of injury history, gluteus medius activity was similar between groups during the loading phase of stance.     

Hip external rotation stiffness and midfoot passive mechanical resistance are associated with lower limb movement in the frontal and transverse planes during gait

BackgroundHip external rotation stiffness, midfoot passive mechanical resistance and foot alignment may influence on ankle, knee and hip movement in the frontal and transverse planes during gait.Research questionAre hip stiffness, midfoot mechanical resistance and foot alignment associated with ankle, knee and hip kinematics during gait?MethodsHip stiffness, midfoot mechanical resistance, and foot alignment of thirty healthy participants (18 females and 12 males) with average age of 25.4 years were measured. In addition, lower limb kinematic data during the stance phase of gait were collected with the Qualisys System (Oqus 7+). Stepwise multiple linear regressions were performed to identify if hip stiffness, midfoot torque, midfoot stiffness and foot alignment were associated with hip and knee movement in the transverse plane and ankle movement in the frontal plane with α = 0.05.ResultsReduced midfoot torque was associated with higher hip range of motion (ROM) in the transverse plane (r² = 0.18), reduced hip stiffness was associated with higher peak hip internal rotation (r² = 0.16) and higher ROM in the frontal plane (r² = 0.14), reduced midfoot stiffness was associated with higher peak knee internal rotation (r² = 0.14) and increased midfoot torque and midfoot stiffness were associated with higher peak knee external rotation (r² = 0.36).SignificanceThese findings demonstrated that individuals with reduced hip and midfoot stiffness have higher hip and knee internal rotation and higher ankle eversion during the stance phase of gait. On the other hand, individuals with increased midfoot torque and stiffness have higher knee external rotation. These relationships can be explained by the coupling between ankle movements in the frontal plane and knee and hip movements in the transverse plane. Finally, this study suggests that midfoot passive mechanical resistance and hip stiffness should be assessed in individuals presenting altered ankle, knee and hip movement during gait.     

Effect of footwear on high and low arched runners' mechanics during a prolonged run

INTRODUCTION: Running shoes are designed specifically for different foot types in order to reduce injuries. Running in the correct footwear matched for foot type may have a greater influence on mechanics when runners become exerted. Therefore, the purpose of this study was to evaluate changes in kinematics and kinetics over the course of a prolonged run when low (LA) and high (HA) arched runners wear motion control and cushioning shoes. METHODS: Twelve HA and 12 LA recreational runners were recruited for this study. Subjects ran in a motion control (MC) and cushion trainer (CT) shoe. Lower extremity kinematics and tibial accelerometry were collected while the runners ran at a self-selected training pace. The data were analyzed using a two-way (footwear x time) repeated measures ANOVA (p=0.05) for each arch type. RESULTS: Low arched runners: Peak tibial internal rotation decreased in the MC shoe and was increased in the CT over the course of the prolonged run. However, no interactions or main effects were noted for peak eversion or eversion excursion. High arched runners: No shoe by time interaction was observed for tibial shock. However, there was a main effect for shoe, with lower tibial shock associated with the CT shoe. CONCLUSION: In LA runners, MC shoes decreased tibial internal rotation compared to CT shoes over the course of a prolonged run. In HA runners, running in the CT shoes reduced tibial shock compared to the MC shoes.     

The characteristics of gait in Charcot-Marie-Tooth disease types I and II

Certain typical gait characteristics such as foot-drop and foot supination are well described in Charcot-Marie-Tooth disease. These are directly related to the primary disease and due to the weakness of ankle dorsiflexors and everters characteristic of this hereditary neuropathy. We analysed 16 subjects aged 8-52 years old (11 with type I, 5 with type II Charcot-Marie-Tooth disease) using three-dimensional gait analysis and identified kinematic features previously unreported. These patients showed a combination of tight tendo achillei, foot-drop, failure of plantar flexion and increased foot supination, but also presented with excessive internal rotation of the knee and/or tibia, knee hyperextension in stance, excessive external rotation at the hips and decreased hip adduction in stance (typical of a broad based gait). These proximal features could have been an adaptation to or consequence of the disrupted ankle and foot biomechanics, however a direct relation to the neuropathy is also possible since sub-normal muscle power was observed at the proximal levels in most subjects on both manual testing and kinetic analysis. Gait analysis is a useful tool in defining the characteristic gait of patients with Charcot-Marie-Tooth disease.