Article

Step width alters iliotibial band strain during running

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Abstract

This study assessed the effect of step width during running on factors related to iliotibial band (ITB) syndrome. Three-dimensional (3D) kinematics and kinetics were recorded from 15 healthy recreational runners during overground running under various step width conditions (preferred and at least +/- 5% of their leg length). Strain and strain rate were estimated from a musculoskeletal model of the lower extremity. Greater ITB strain and strain rate were found in the narrower step width condition (p < 0.001, p = 0.040). ITB strain was significantly (p < 0.001) greater in the narrow condition than the preferred and wide conditions and it was greater in the preferred condition than the wide condition. ITB strain rate was significantly greater in the narrow condition than the wide condition (p = 0.020). Polynomial contrasts revealed a linear increase in both ITB strain and strain rate with decreasing step width. We conclude that relatively small decreases in step width can substantially increase ITB strain as well as strain rates. Increasing step width during running, especially in persons whose running style is characterized by a narrow step width, may be beneficial in the treatment and prevention of running-related ITB syndrome.

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... It was assumed that the ITB followed the same anatomical pathway as the tensor fascia latae. 4,13,20,23 For each of the 3 degrees of freedom of the knee and hip joints, a polynomial equation was fitted by exporting the tensor fascia latae length change as a function of joint angle, as defined in OpenSim (see the APPENDIX, available at www.jospt.org). 8 Iliotibial band resting length was individually adjusted to equal the distance that connected markers on the right anterior superior iliac spine, greater trochanter, lateral femoral epicondyle, and lateral tibial epicondyle. ...
... 4 Peak ITB strain was 0.4% lower in males than in females, similar to changes of 0.3% lower with shorter stride length 4 and 0.5% lower with widened step width. 20 The observed 10.9%/s difference in peak strain rate between sexes is larger than reported differences in step width 20 and step length, 4 but slightly less than the reported difference of 12.7%/s between individuals with ITBS and healthy controls. 13 The difference in peak strain rate between males and females being similar to the difference between individuals who developed ITBS and those who did not may suggest that females are more at risk of developing ITBS. ...
... Validation would be difficult without invasive measures, but the strain magnitudes (4%-7%) were within normal in vivo limits of elastic tissue 24 and lower than the failure point identified by cadaver testing. 2 The estimated ITB mechanics also do not reflect whether participants have a tighter or stiffer ITB, or factor in muscle activation, as our model is similar to previous passive tissue ITB models. 4,13,20,23 Last, investigating the effectiveness of wedge orthoses for prevention or rehabilitation of ITBS would be better served with a longitudinal study design that involved symptomatic individuals with ITBS. [11][12][13]23,28 Additionally, inclusion of a fatigue protocol, which has been associated with ITBS symptom onset, would be of benefit to understanding the effectiveness of the wedge orthosis. ...
Article
Study design: Within-subjects repeated measures design. Background: Previous research has identified that iliotibial band syndrome (ITBS) is more prevalent in females than males. It has been theorized that high iliotibial band (ITB) strain rate is a primary etiological factor for developing ITBS. Orthotics are commonly used to influence gait mechanics and may reduce ITB strain rate due to influencing alterations in the kinematic chain. Objectives: Identify how wedge orthoses and sex affect ITB strain and strain rate. Methods: Thirty (15 male, 15 female) asymptomatic participants ran with lateral 7°, lateral 3°, no wedge, medial 3°, and medial 7° wedges. Subjects ran overground and data were collected with a motion capture system and force platform. ITB strain and strain rate were estimated using a novel six degree of freedom musculoskeletal model. A mixed model MANCOVA for between-subjects comparison of sex and within-subjects comparison of wedge was used. Results: There were no significant differences in ITB strain or strain rate between wedge conditions. Females had significantly higher ITB strain and strain rate compared to males. Conclusions: Clinicians should be aware that medial wedges may not acutely alter ITB strain or strain rate. Females exhibited greater peak ITB strain and strain rate, potentially due to increased hip internal rotation compared to males. Further research is needed investigating longitudinal effects of the wedges. J Orthop Sports Phys Ther, Epub 31 Aug 2019. doi:10.2519/jospt.2019.8837.
... These authors presumed that excessive hip adduction and knee internal rotation increases ITB strain, causing the ITB to compress against the lateral femoral condyle. Research using a musculoskeletal model has reported that increasing step width during running reduces ITB strain and the strain rates mediated by decreased hip adduction (Meardon et al., 2012). These findings strongly suggest that kinematic changes, especially in hip motion in the frontal plane, significantly influence ITB stiffness. ...
... Posture and gait re-training has been included as a treatment intervention for the patients with ITB syndrome (Fredericson and Weir, 2006;Meardon et al., 2012;Allen, 2014;Hunter et al., 2014). Various points of modification have been recommended, including widening the step width, altering the pelvic external rotation, running at a fast pace that increases knee flexion, and increasing the cadence to reduce the work at the knee (Fredericson and Weir, 2006;Meardon et al., 2012;Allen, 2014;Hunter et al., 2014). ...
... Posture and gait re-training has been included as a treatment intervention for the patients with ITB syndrome (Fredericson and Weir, 2006;Meardon et al., 2012;Allen, 2014;Hunter et al., 2014). Various points of modification have been recommended, including widening the step width, altering the pelvic external rotation, running at a fast pace that increases knee flexion, and increasing the cadence to reduce the work at the knee (Fredericson and Weir, 2006;Meardon et al., 2012;Allen, 2014;Hunter et al., 2014). Relief of lateral knee pain was also reported following treatment that emphasizes gait re-training (Allen, 2014;Hunter et al., 2014). ...
Article
To understand and treat iliotibial band (ITB) syndrome, caused by excessive compression between the ITB and lateral femoral condyle, it is important to identify factors contributing to an increase in ITB stiffness. The purpose of this study was to clarify the factors that contribute to an increase in ITB stiffness by examining the relationship between three-dimensional postural changes and ITB stiffness. Fourteen healthy individuals performed one-leg standing under 7 conditions (including normal one-leg standing as a control condition) in which the pelvic position was changed in three planes. The shear elastic modulus in the ITB was measured using shear-wave elastography, as a measure of ITB stiffness. The three-dimensional joint angles and external joint moments in the hip and knee joints were also measured to confirm the changes in joint angles and external load. Compared to the normal one-leg standing condition, ITB stiffness was significantly increased in the pelvic posterior tilted position (i.e. hip extension), contralateral pelvic dropped position (i.e. hip adduction), and contralateral pelvic posterior rotated position (i.e. hip external rotation). The findings suggest that interventions to reduce hip extension, adduction, and external rotation might be useful if these excessive positional changes are detected in patients with ITB syndrome.
... 25 Three studies 55 83 95 evaluated the biomechanical effects of cues to reduce impact loading variables at foot strike. Four studies [84][85][86][87] evaluated the biomechanical effects of altering step width, but none of these included symptomatic participants. Three studies evaluated the biomechanical effects of cues to alter proximal mechanics, 22 23 88 with two aiming to reduce hip adduction, 22 23 and one to increase forward trunk lean. ...
... And then in those cases, you do think about (promoting) maybe a little bit wider stride." (14) Cues to reduce hip adduction-limited evidence indicates ↓ peak hip adduction and contralateral pelvic drop at 3 months follow-up 22 23 Cues to increase step width-very limited evidence indicates ↓ peak internal knee abduction moment, 84 ↓ internal knee abduction impulse, 84 ↓ ITB strain and strain rate, 85 and ↓ peak hip adduction 84 85 Patellar tendinopathy Cautious recommendations for running retraining to assist by some Consider increasing step rate, strategies to reduce overstride and impact loading variables, and transition from rearfoot to forefoot strike "You often find these individuals very different to patellofemoral pain where you'll get a greater hip adduction. They often have good hip control, but they do have the over-stride pattern where they're landing quite heavy on the heel (which should be changed). ...
... (16) Increasing step rate-limited evidence indicates ↓ hip energy absorption 63 66 ↓ peak internal hip extensor moment 66 71 Continued treatment of ITBS (table 3), an approach supported by findings that greater peak adduction in female runners may be a risk factor for ITBS development. 101 Additionally, increasing step width to reduce cross-over gait (hip adduction at foot strike) was suggested (table 3), and this is supported by very limited to limited evidence for reduced peak internal knee abduction moment and impulse, 84 ITB strain and strain rate, 85 and peak hip adduction 84 85 (see online supplementary file 7). There were inconsistent beliefs regarding the potential for running retraining to assist in the treatment of patellar tendinopathy (table 3), with some cautious recommendations to consider reducing overstride, increasing step rate, reducing impact loading variables, and transitioning from a rearfoot to a midfoot or forefoot strike. ...
Article
Importance Running-related injuries are highly prevalent. Objective Synthesise published evidence with international expert opinion on the use of running retraining when treating lower limb injuries. Design Mixed methods. Methods A systematic review of clinical and biomechanical findings related to running retraining interventions were synthesised and combined with semistructured interviews with 16 international experts covering clinical reasoning related to the implementation of running retraining. Results Limited evidence supports the effectiveness of transition from rearfoot to forefoot or midfoot strike and increase step rate or altering proximal mechanics in individuals with anterior exertional lower leg pain; and visual and verbal feedback to reduce hip adduction in females with patellofemoral pain. Despite the paucity of clinical evidence, experts recommended running retraining for: iliotibial band syndrome; plantar fasciopathy (fasciitis); Achilles, patellar, proximal hamstring and gluteal tendinopathy; calf pain; and medial tibial stress syndrome. Tailoring approaches to each injury and individual was recommended to optimise outcomes. Substantial evidence exists for the immediate biomechanical effects of running retraining interventions (46 studies), including evaluation of step rate and strike pattern manipulation, strategies to alter proximal kinematics and cues to reduce impact loading variables. Summary and relevance Our synthesis of published evidence related to clinical outcomes and biomechanical effects with expert opinion indicates running retraining warrants consideration in the treatment of lower limb injuries in clinical practice.
... Typical step width during running is approximately 3 to 6 cm 1,3,20,25 and does not seem to differ between habitual foot strike groups. 20 A narrower step causes greater iliotibial band (ITB) strain and strain rate, 25 increased frontal plane ankle and knee moments, 3 and increased peak rearfoot eversion and hip adduction angles. 3 Greater hip adduction and knee internal rotation have been retrospectively and prospectively found in runners with ITB syndrome and patellofemoral pain syndrome, 12,29,30,35 and peak hip adduction and rearfoot eversion are greater in females with a history of tibial stress fractures. ...
... However, all of these studies have looked only at habitual rearfoot, 8,9,18,19,27,32 did not state the foot strike pattern used by runners, 1,3,11,22,26 or did not differentiate between foot strike style groups. 25 These variables should be investigated in FFS, especially with a recent interest in minimalist shoes and barefoot running, which generally encourage the use of a FFS. 7,17,23 Therefore, the primary purpose of this study was to compare step width, free moment, ITB strain and strain rate, and select lower extremity frontal and transverse plane kinematics when stride length was shortened 5% and 10% in habitual rearfoot and habitual mid-/forefoot runners using both foot strike patterns while shod. ...
... The ITB strain and strain rate were calculated using a scaled lower extremity model from OpenSIM, 2 except that we defined the ITB attachments using the 5 points from Meardon et al. 25 Animation of the model was implemented using custom Matlab software (7.13.0.564, R2011b). ...
Article
Some frontal plane and transverse plane variables have been associated with running injury, but it is not known if they differ with foot strike style or as stride length is shortened. To identify if step width, iliotibial band strain and strain rate, positive and negative free moment, pelvic drop, hip adduction, knee internal rotation, and rearfoot eversion differ between habitual rearfoot and habitual mid-/forefoot strikers when running with both a rearfoot strike (RFS) and a mid-/forefoot strike (FFS) at 3 stride lengths. Controlled laboratory study. A total of 42 healthy runners (21 habitual rearfoot, 21 habitual mid-/forefoot) ran overground at 3.35 m/s with both a RFS and a FFS at their preferred stride lengths and 5% and 10% shorter. Variables did not differ between habitual groups. Step width was 1.5 cm narrower for FFS, widening to 0.8 cm as stride length shortened. Iliotibial band strain and strain rate did not differ between foot strikes but decreased as stride length shortened (0.3% and 1.8%/s, respectively). Pelvic drop was reduced 0.7° for FFS compared with RFS, and both pelvic drop and hip adduction decreased as stride length shortened (0.8° and 1.5°, respectively). Peak knee internal rotation was not affected by foot strike or stride length. Peak rearfoot eversion was not different between foot strikes but decreased 0.6° as stride length shortened. Peak positive free moment (normalized to body weight [BW] and height [h]) was not affected by foot strike or stride length. Peak negative free moment was -0.0038 BW·m/h greater for FFS and decreased -0.0004 BW·m/h as stride length shortened. The small decreases in most variables as stride length shortened were likely associated with the concomitant wider step width. RFS had slightly greater pelvic drop, while FFS had slightly narrower step width and greater negative free moment. Shortening one's stride length may decrease or at least not increase propensity for running injuries based on the variables that we measured. One foot strike style does not appear universally better than the other; rather, different foot strike styles may predispose runners to different types of injuries. © 2015 The Author(s).
... Interventions that directly target running biomechanics suspected to increase ITB strain, and subsequent compressive loads acting on the lateral knee, may have promise. For instance, Meardon et al. used a subject-specific musculoskeletal model during running to show that a wider step width reduces ITB strain [100]. Feedback on step width can easily be provided with a full-length mirror during treadmill running. ...
... Current approaches to diagnosis, treatment and understanding of ITBS function are insufficient, indicating a much larger issue of a lack of understanding of the ITB's fundamental mechanical function. Further, this research is primarily dependent on simplified musculoskeletal models that often fail to include the GMAX's potential contribution to ITB strain [100,101]. ...
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Article
The development of a pronounced iliotibial band (ITB) is an anatomically distinct evolution of humans. The mechanical behaviour of this “new” structure is still poorly understood and hotly debated in current literature. Iliotibial band syndrome (ITBS) is one of the leading causes of lateral knee pain injuries in runners. We currently lack a comprehensive understanding of the healthy behaviour of the ITB, and this is necessary prior to further investigating the aetiology of pathologies like ITBS. Therefore, the purpose of this narrative review was to collate the anatomical, biomechanical and clinical literature to understand how the mechanical function of the ITB is influenced by anatomical variation, posture and muscle activation. The complexity of understanding the mechanical function of the ITB is due, in part, to the presence of its two in-series muscles: gluteus maximus (GMAX) and tensor fascia latae (TFL). At present, we lack a fundamental understanding of how GMAX and TFL transmit force through the ITB and what mechanical role the ITB plays for movements like walking or running. While there is a range of proposed ITBS treatment strategies, robust evidence for effective treatments is still lacking. Interventions that directly target the running biomechanics suspected to increase either ITB strain or compression of lateral knee structures may have promise, but clinical randomised controlled trials are still required.
... One non-modifiable factor is small pelvic width, which might contribute to increased compressive forces by decreasing a 1 and, thereby, the a 1 þ a 2 sum of angles. In confirmation of this hypothesis, a recent study in college athletes found smaller distances between femoral heads, greater trochanters and anterior superior iliac spines to be associated with a smaller base of gait during running (Heiderscheit et al., 2020), which, in turn, has been suggested to favor the development of ITBS (Meardon et al., 2012). At the knee, more prominent lateral femoral epicondyles would move the point of ITB deflection further laterally, which would equally result in more acute a 1 and a 2 angles. ...
... Moreover, joint malalignments may also affect the degree of ITB strain and tensile stress. As an example, knee varus and internal rotation shift Gerdy's tubercle in the medial direction, which increases ITB strain (Baker et al., 2018;Ferber et al., 2010;Hamill et al., 2008;Kim et al., 2020;Meardon et al., 2012;Stickley et al., 2018). Such tensioning might limit the tendon's capacity to dampen force peaks by storing elastic energy. ...
Article
Objective Iliotibial band syndrome (ITBS) is presumably caused by excessive tension in the iliotibial band (ITB) leading to compression and inflammation of tissues lying beneath it. Usually managed conservatively, there is a lack of scientific evidence supporting the treatment recommendations, and high symptom recurrence rates cast doubt on their causal effectiveness. This review discusses the influence of common physiotherapeutic measures on risk factors contributing to tissue compression beneath the ITB. Methods The potential pathogenic factors are presented on the basis of a simple biomechanical model showing the forces acting on the lateral aspect of the knee. Existent literature on the most commonly prescribed physiotherapeutic interventions is critically discussed against the background of this model. Practical recommendations for the optimization of physiotherapy are derived. Results According to biomechanical considerations, ITBS may be promoted by anatomical predisposition, joint malalignments, aberrant activation of inserting muscles as well as excessive ITB stiffness. Hip abductor strengthening may correct excessive hip adduction but also increase ITB strain. Intermittent stretching interventions are unlikely to change the ITB's length or mechanical properties. Running retraining is a promising yet understudied intervention. Conclusions High-quality research directly testing different physiotherapeutic treatment approaches in randomized controlled trials is needed.
... Moreover, excessive hip adduction during running extends the ITB and increases tension, placing greater strain on the ITB. 10 However, these studies have estimated the strain of the ITB using simulation systems. [7][8][9][10] Very few studies have directly measured the strain of the ITB. ...
... Moreover, excessive hip adduction during running extends the ITB and increases tension, placing greater strain on the ITB. 10 However, these studies have estimated the strain of the ITB using simulation systems. [7][8][9][10] Very few studies have directly measured the strain of the ITB. Tateuchi et al 11 measured the strain of the ITB in vivo using shear wave elastography in seven different pelvic positions during one-leg standing with threedimensional joint angles and external joint moments in hip and knee joints. ...
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Article
Background: Increased strain of the iliotibial band (ITB) is a plausible contributing factor for the development of iliotibial band syndrome (ITBS). Although several studies have found relationships between the strain of the ITB and kinematic factors during running, the associations of the ITB strain with knee alignment and sex, which are considered intrinsic factors, are not well understood. Objective: To clarify the sex differences in the ITB strain between genu varum and normal knee alignments in different postures. Design: Observational cross-sectional study. Setting: Laboratory research within a university. Participants: Forty-four healthy recreational athletes (21 men and 23 women) volunteered for this study and were divided into four groups by sex and knee alignment: men with genu varum alignment, men with normal knee alignment, women with genu varum alignment, and women with normal knee alignment. Main outcome measures: Ultrasound elastography was used for distal ITB strain measurements in weight bearing and four different non-weight bearing postures: neutral, knee flexion, hip adduction and hip adduction with knee flexion. Results: There were no significant differences in neutral and hip adduction postures among the four groups. However, during weight bearing, the women's genu varum group (6.91 ± 1.69) exhibited greater strain than both the men's normal group (3.50 ± 1.04, P = .005) and the women's normal group (4.42 ± 1.42, P = .048). In addition, there were significant positive correlations between the intercondylar distance and the ITB strain during weight bearing (r = 0.315, P = .037). Conclusions: The women's genu varum group exhibited a higher ITB strain during weight bearing, which may be related to the high incidence of ITBS in women athletes. Furthermore, the changes in alignment and muscle activities during weight bearing could influence the strain of the ITB. This article is protected by copyright. All rights reserved.
... 2017; Clansey, Hanlon, Wallace, & Lake, 2012; Dallinga, Van Rijn, Stubbe, & Deutekom, 2019; Daoud et al., 2012; Dudley, Pamukoff, Lynn, Kersey, & Noffal, 2017; Hayes, Boulos, & Cruz, 2019; Hubbard, Mullis Carpenter, & Cordova, 2009; Kluitenberg et al., 2015; Kluitenberg et al., 2016; Leppe & Besomi, 2018; Lorimer & Hume, 2014; Luedke, Heiderscheit, Williams, & Rauh, 2015; Luedke, Heiderscheit, Williams, & Rauh, 2016;Malisoux et al., 2015;Meardon, Campbell, & Derrick, 2012;Messier et al., 2018;Nakajima, Wu, & Becker, 2018;Napier, MacLean, Maurer, Taunton, & Hunt, 2019;Napier, MacLean, Maurer, Taunton, & Hunt, 2018;Nielsen et al., 2013; Ø Stergaard Nielsen et al., 2014; P e rez-Morcillo et al., 2019;Rauh, 2018;Rauh, 2014;Rauh, Barrack, & Nichols, ...
Article
Objective To develop a trail running injury screening instrument (TRISI) for utilisation as clinical decision aid in determining if a trail runner is at an increased risk for injury. Design Multiple methods approach. Methods The study utilised five phases 1) identification of injury risk factors 2) determining the relevance of each identified risk factor in a trail running context, 3) creating the content of the Likert scale points from 0 to 4, 4) rescaling the Likert scale points to determine numerical values for the content of each Likert scale point, and 5) determining a weighted score for each injury risk factor that contributes to the overall combined composite score. Results Of the 77 identified injury risk factors, 26 were deemed relevant in trail running. The weighted score for each injury risk factor ranged from 2.21 to 5.53 with the highest calculated score being 5.53. The final TRISI includes risk categories of training, running equipment, demographics, previous injury, behavioural, psychological, nutrition, chronic disease, physiological, and biomechanical factors. Conclusion The developed TRISI aims to assist the clinician during pre-race injury screening or during a training season to identify meaningful areas to target in designing injury risk management strategies and/or continuous health education.
... In addition to these variables, the step width (SW) defines the mediolateral distance between 2 consecutive steps during running. For experienced runners, the SW during natural running (3.5-4 m/s) ranges from 0.02 to 0.06 m [1,10,11,15]. In contrast, SW during sprinting is relatively wide, as SW values of elite and national level sprinters decrease from 0.39 m at the initial step to 0.17 m in the maximal speed phase during accelerated sprinting [7]. ...
Article
This study aimed to describe changes in step width (SW) during accelerated sprinting, and to clarify the relationship of SW with sprinting performance and ground reaction forces. 17 male athletes performed maximal-effort 60 m sprints. The SW and other spatiotemporal variables, as well as ground reaction impulses, over a 52 m distance were calculated. Average values for each 4 steps during acceleration were calculated to examine relationships among variables in different sections. The SW rapidly decreased up to the 13th step and slightly afterward during accelerated sprinting, showing a bilinear phase profile. The ratio of SW to the stature was significantly correlated with running speed based on average values over the 52 m distance and in the 9th-12th step section during accelerated sprinting. The SW ratio positively correlated with medial, lateral and mediolateral impulses in all step sections, except for medial impulse in the 17th-20th step section. These results indicate the importance of wider SW for better sprinting performance, especially in the 9th-12th step section. Moreover, the wider SW was associated with larger medial impulse and smaller lateral impulse, suggesting that a wide SW contributes to the production of greater mediolateral body velocity during accelerated sprinting.
... In another study, hip adduction was also significantly increased in female runners who developed iliotibial band syndrome during follow-up (Noehren, Davis, & Hamill, 2007). In addition, these movement patterns have been related to increased patellofemoral joint stress (Huberti & Hayes, 1984;Liao, Yang, Ho, Farrokhi, & Powers, 2015), iliotibial band strain and strain rates (Meardon, Campbell, & Derrick, 2012), tibial bone stress (Meardon & Derrick, 2014) and tensile and compressive loading of the gluteal tendons (Grimaldi & Fearon, 2015). Based on the relationships between running kinematics, structural loading and running injuries, the ability to reliably and accurately evaluate individual running kinematics in clinical settings has become an essential component in the process of preventing running (re-)injuries (Souza, 2016). ...
Article
Objectives: To investigate the temporal relationship between two-dimensional measured frontal plane joint angles and three-dimensional measured kinematic profiles during the stance phase of running, and to assess the intra- and intertester reliability of the two-dimensional angles. Design: Observational study. Setting: Research laboratory. Participants: Fifteen injury-free elite athletes. Main outcome measures: Contralateral pelvic drop (CPD), femoral adduction (FA), hip adduction (HA) and knee valgus (KV) were measured at the deepest landing position during midstance with two-dimensional video analysis during running. CPD, HA and knee abduction were measured continuously during the entire stance phase through three-dimensional motion analysis. One-dimensional statistical parametric mapping was used to examine the temporal relationships between the two-dimensional angles and three-dimensional kinematic profiles. In addition, intra-class correlation coefficients (ICC) were calculated to assess the intra- and intertester reliability of the two-dimensional angles. Results: Two-dimensional CPD, FA and HA were significantly related to the three-dimensional HA kinematic profile. Two-dimensional CPD was significantly related to the three-dimensional CPD kinematic profile. No significant relationship was found between two-dimensional KV and three-dimensional knee abduction. Excellent intra- and intertester reliability was found for the two-dimensional angles (ICC 0.90-0.99). Conclusions: These findings support implementing two-dimensional video analysis to evaluate CPD and HA during running.
... The mismatch between the full-body and reduced model, at both running speeds, provides insight into the relative contribution of the arms to CoM motion in the ML direction. Previous research has shown that humans will adopt a small, but non-zero, step width during unconstrained treadmill running, typically about 2-4cm [13,14]. Running with a non-zero step width will require a displacement between the CoM and the stance foot in order to generate the moment, about the base of support, required to transition onto the contralateral foot. ...
Article
Accurate measurement of centre of mass (CoM) motion can provide valuable insight into the biomechanics of human running. However, full-body kinematic measurement protocols can be time consuming and difficult to implement. Therefore, this study was performed to understand whether CoM motion during running could be estimated from a model incorporating only lower extremity, pelvic and trunk segments. Full-body kinematic data was collected whilst (n = 12) participants ran on a treadmill at two speeds (3.1 and 3.9 ms⁻¹). CoM trajectories from a full-body model (16-segments) were compared to those estimated from a reduced model (excluding the head and arms). The data showed that, provided an offset was included, it was possible to accurately estimate CoM trajectory in both the anterior-posterior and vertical direction, with root mean square errors of 5 mm in both directions and close matches in waveform similarity (r = 0.975-1.000). However, in the ML direction, there was a considerable difference in the CoM trajectories of the two models (r = 0.774-0.767). This finding suggests that a full-body model is required if CoM motions are to be measured in the ML direction. The mismatch between the reduced and full-body model highlights the important contribution of the arms to CoM motion in the ML direction. We suggest that this control strategy, of using the arms rather than the heavier trunk segments to generate CoM motion, may lead to less variability in CoM motion in the ML direction and subsequently less variability in step width during human running.
... 14,21 The abnormal and excessive tensioning of the iliotibial band may be related to hypertonicity of the gluteus maximus, 15 increased activation of the tensor fascia lata and gluteus maximus, 15 and rapid rate of loading of the iliotibial band. 26,27 The compression and friction models overlap. Jelsing and colleagues 25 demonstrated using sonographic evaluation that the iliotibial band at the lateral femoral Relationships of the iliotibial band lumbar spine to knee. ...
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Article
Iliotibial band syndrome (ITBS) has known biomechanical factors with an unclear explanation based on only strength and flexibility deficits. Neuromuscular coordination has emerged as a likely reason for kinematic faults guiding research toward motor control. This article discusses ITBS in relation to muscle performance factors, fascial considerations, epidemiology, functional anatomy, strength deficits, kinematics, iliotibial strain and strain rate, and biomechanical considerations. Evidence-based exercise approaches are reviewed for ITBS, including related methods used to train the posterior hip muscles.
... A narrow base of support has been linked to tibial stress fractures, iliotibial band syndrome, and several kinematic patterns that have been associated with running injuries, such as excessive hip adduction and overpronation. [35][36][37] As such, this variable should be evaluated in all runners, and runners with a "cross-over sign" or "scissoring gait," characterized by an overly narrow base of support, may consider modification. ...
Article
Running biomechanics play an important role in the development of injuries. Performing a running biomechanics analysis on injured runners can help to develop treatment strategies. This article provides a framework for a systematic video-based running biomechanics analysis plan based on the current evidence on running injuries, using 2-dimensional (2D) video and readily available tools. Fourteen measurements are proposed in this analysis plan from lateral and posterior video. Identifying simple 2D surrogates for 3D biomechanic variables of interest allows for widespread translation of best practices, and have the best opportunity to impact the highly prevalent problem of the injured runner.
... Treadmill running was performed to assess pain severity only. An extended value would be to evaluate ITBS-related factors such as running technique (4,5) and hip abductor weakness. (6) That a more thorough assessment (of both body structures and active functioning) for accurate diagnosis is preferred, is highlighted by the finding that one patient was left undiagnosed from meniscal problems for more than four weeks (p.29). ...
... Running with a step width less than the preferred step width is associated with gait mechanics similar to those reported in people with tibial stress fracture (Brindle et al., 2013;McClay, 1995;Pohl et al., 2006;Williams and Ziff, 1991). For example, reduced step width during running has been linked to an increase in rearfoot pronation (Brindle et al., 2013;Pohl et al., 2006) and greater hip adduction and knee internal rotation (Brindle et al., 2013;Meardon et al., 2012). Pilot work from our lab also suggests that step width during running is negatively associated with the free moment, (Meardon and Derrick, 2008) frontal plane hip, and knee and ankle joint moments (Meardon and Derrick, 2011). ...
... They include friction of ITB against the lateral femoral epicondyle during repetitive flexion and extension, compression of the fat and connective tissue deep to the ITB, and chronic inflammation of the ITB bursa. There is less evidence that a pathologic change takes place in the ITB itself [1,2,4]. ...
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Article
A 64-year-old woman visited our pain clinic with the pain of right lateral side of thigh for one year. Her pain always started from knee and was radiated to buttock area when symptom was severe. She showed significant tenderness at knee lateral side and local tightness at lateral thigh. Magnetic resonance image of the knee was performed and we could identify high signal intensity of iliotibial band through coronal and axial view. In spite of medication and physical stretching exercise of iliotibial band for one month, she did not show any improvement of pain. To alleviate her symptom, ultrasound guided local corticosteroid injection targeting beneath the iliotibial band was performed. After the procedure, the reduction of pain was significant and there was no need for further management.
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These days the attention of health care providers has been focused on improving the quality of lives of the patients. From women's point of view, reproductive health problems are the major morbidities. A technical working group of W.H.O. in 1989 suggested three categories of reproductive morbidity viz. obstetric morbidity, gynecological morbidity and contraceptive morbidity. Obstetric morbidity originates from any cause related to pregnancy or its management. Millions of women experience involuntary losses of urine called urinary incontinence (UI) which is highly mental, physical and social disability of women. Three types of urinary incontinence are found which are very much common and especially in case of multi-gravida women. Stress urinary incontinences are most often associated with pelvic floor muscle laxity. This involves involuntary urinary leakage when intra-abdominal pressure increases such as during physical exertion or when coughing, sneezing or laughing. Urge incontinence is most often caused by detrusor over-activity. The detrusor muscle malfunctions contracting involuntarily during bladder filling; this forces urine through urethra. The volume of urine lost in episodes varies greatly. Mixed urinary incontinence refers either to a combination of stress urinary incontinence and urge incontinence symptoms or to the presence of both detrusor instability and pelvic floor laxity. KEYWORDS: Morbidity, Incontinance, Kegel, Utrine Prolapse, Women Health.
Article
Background Novice runners with pronated feet are at an increased risk of running-related injuries. However, not all runners with pronated feet have increased foot pronation during running. Moreover, although foot muscle morphology is related to static foot alignment, the relationship between foot muscle morphology and foot kinematics during running remains unclear. We aimed to determine foot kinematic patterns during running among novice runners with pronated feet and the presence of a relationship between these foot kinematic patterns and foot muscle morphology. Methods Twenty-one novice runners with pronated feet participated in this study, and data on 39 lower limbs were collected. Data on foot kinematics during running (rearfoot strike) were collected using a three-dimensional motion capture system in terms of navicular height (NH) at initial contact and dynamic navicular drop (DND). A hierarchical cluster analysis method was used to identify the optimal number of clusters based on these two foot-related kinematic variables. Following identification of the clusters, differences in cluster variables and cross-sectional areas of selected foot muscles assessed using ultrasonography in each cluster were examined. The muscles of interest included the abductor hallucis, flexor hallucis brevis and longus, flexor digitorum brevis and longus, and peroneus longus. Results Three subgroups were identified based on foot kinematics during running: cluster 1, lowest NH at initial contact and larger DND; cluster 2, moderate NH at initial contact and smaller DND; and cluster 3, highest NH at initial contact and larger DND. Clusters 1 and 3 had a larger abductor hallucis compared with cluster 2, and cluster 3 had a larger flexor hallucis brevis compared with cluster 2. Significance These subgroups may differ in terms of resistance to and type of running-related injury. Moreover, foot kinematics during running is possibly impacted by the morphology and function of medial intrinsic foot muscles.
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Verletzungen des Kniegelenkes können zu langen Ausfallzeiten im Sport führen. Dieses Kapitel gibt eine Übersicht über Diagnostik und Therapie von akuten und chronischen Beschwerden am Kniegelenk bei Sportlern. Ausgehend von der aktuellen Evidenz wird der kriterienbasierte Rehabilitationsverlauf für die unterschiedlichen Kniegelenkverletzungen dargestellt. Darüber hinaus wird der Return to Sport-Prozess mit den jeweiligen intrarehabilitativen Assessments anhand biomechanischer und verletzungsspezifischer Überlegungen veranschaulicht.
Article
[Main text in Slovene]. Iliotibial band syndrome (ITBS) is one of the most common running-related injuries. The purpose of this systematic review with meta-analysis was to investigate the risk factors for occurrence of ITBS. After systematic search of the PubMed database, 20 case-controland 3 prospective studies that reported differences between runners with ITBS and uninjured controls were included into the meta-analysis. Our results revealed statistically significantly lower hip abductor strength (standardized mean difference (SMD) = 0.80; p = 0.020) and lower eversion range of motion during stance phase (SMD = -0.45; p = 0.003). No other statistically significant differences were found between the runners with PSIT and uninjured runners. It is advised that runners included hip abductor strengthening exercises into their training regimen. On the other hand, it remains uncertain whether lower ankle eversion during stance phase is the cause or the consequence of ITBS. Therefore, no reliable evidence-based guidelines for exercising the ankle can be given.
Article
Context A narrow base of gait (BOG), the mediolateral distance between the foot and body's line of gravity at midstance, during running is a suggested cause of injuries such as iliotibial band syndrome and tibial stress injury. However, an understanding of modifiable and nonmodifiable factors that influence BOG is lacking, which limits the development of corrective strategies. Objective To determine if BOG varies by sex and running speed and the influence of running kinematics and anthropometrics on BOG. Design Cross-sectional study. Setting Record review of routinely collected performance data from a National Collegiate Athletic Association Division I intercollegiate athletic program. Patients or Other Participants A total of 166 Division I collegiate athletes (basketball, cross-country, football, soccer). Main Outcome Measure(s) Running biomechanics (N = 166) and dual-energy x-ray absorptiometry-derived anthropometric data (n = 68) were extracted. Running variables were BOG, step rate, stride length, foot-inclination angle, center-of-mass vertical displacement, heel-to-center of mass anteroposterior distance, and peak stance-phase angles: hip flexion, hip adduction, pelvic drop, knee flexion, and ankle dorsiflexion. Extracted anthropometric variables were height; leg, femur, and tibia length; and anterior-superior iliac spine, hip-joint, and greater trochanter width. We calculated linear mixed-effects models to assess the influence of sex and running speed on BOG and identify the kinematic and anthropometric variables most associated with BOG. Results A significant interaction between sex and running speed on BOG was observed, with males demonstrating a smaller BOG than females at faster speeds and BOG decreasing overall with speed. The kinematic measures most associated with BOG at preferred running speed were foot-inclination angle at initial contact and peak stance-phase hip adduction and ankle dorsiflexion. Anterior-superior iliac spine width was the anthropometric variable most associated with BOG at preferred running speed. Conclusions Sex and running speed must be considered when determining the appropriateness of an individual's BOG. Additionally, BOG was associated with several potentially modifiable kinematic parameters.
Article
Objectives To explore whether homogeneous subgroups could be discriminated within a population of recreational runners with a running-related injury based on running kinematics evaluated with marker-based two-dimensional video analysis. Design Cross-sectional. Setting Research laboratory. Participants Fifty-three recreational runners (15 males, 38 females) with a running-related injury. Main outcome measures Foot and tibia inclination at initial contact, and hip adduction and knee flexion at midstance were measured in the frontal and sagittal plane with marker-based two-dimensional video analysis during shod running on a treadmill at preferred speed. The four outcome measures were clustered using K-means cluster analysis (n = 2–10). Silhouette coefficients were used to detect optimal clustering. Results The cluster analysis led to the classification of two distinct subgroups (mean silhouette coefficient = 0.53). Subgroup 1 (n = 39) was characterized by significantly greater foot inclination and tibia inclination at initial contact compared to subgroup 2 (n = 14). Conclusion The existence of different subgroups demonstrate that the same running-related injury can be represented by different kinematic presentations. A subclassification based on the kinematic presentation may help clinicians in their clinical reasoning process when evaluating runners with a running-related injury and could inform targeted intervention strategy development.
Article
Objectives: To determine whether two-dimensional video analysis could discriminate running kinematics between recreational runners with and without a running-related knee injury. Design: Case-control. Setting: Research laboratory. Participants: Forty-two recreational runners (5 male-13 female injured; 7 male-17 female non-injured). Running-related knee injury was defined as the presence of anterior or lateral knee pain, resulting in altered running activity for at least one week. Main outcome measures: Foot and tibia inclination at initial contact, and lateral trunk position, contralateral pelvic drop, femoral adduction, hip adduction, knee flexion and ankle dorsiflexion at midstance were measured with two-dimensional video analysis during running. Participant characteristics (sex, age, body weight, body length, body mass index, running volume before injury, running speed) and two-dimensional measured angles were compared between groups. Results: No significant differences in participant characteristics between groups were identified (P > .05). The injured group ran with greater contralateral pelvic drop (P = .035), femoral adduction (P = .021) and hip adduction (P = .001) at midstance, and significantly smaller foot inclination at initial contact (P = .031). Conclusion: Two-dimensional video analysis can discriminate kinematics between runners with and without running-related knee injury. Greater contralateral pelvic drop, femoral adduction and hip adduction at midstance may provide running retraining targets for runners with running-related knee injury.
Article
This masterclass takes a multidimensional approach to movement assessment in clinical practice. It seeks to provide innovative views on both emerging and more established methods of assessing movement within the world of movement health, injury prevention and rehabilitation. A historical perspective of the value and complexity of human movement, the role of a physical therapist in function of movement health evaluation across the entire lifespan and a critical appraisal of the current evidence-based approach to identify individual relevant movement patterns is presented. To assist a physical therapist in their role as a movement system specialist, a clinical-oriented overview of current movement-based approaches is proposed within this multidimensional perspective to facilitate the translation of science into practice and vice versa. A Movement Evaluation Model is presented and focuses on the measurable movement outcome of resultants on numerous interactions of individual, environmental and task constraints. The model blends the analysis of preferred movement strategies with a battery of cognitive movement control tests to assist clinical judgement as to how to optimize movement health across an individual lifespan.
Article
Introduction/aim: Foot structure has been implicated as a risk factor of numerous overuse injuries, however, the mechanism linking foot structure and the development of soft-tissue overuse injuries are not well understood. The aim of this study was to identify factors that could predict foot function during walking. Methods: A total of eleven variables (including measures of foot structure, anthropometry and spatiotemporal gait characteristics) were investigated for their predictive ability on identifying kinematic, kinetic and energetic components of the foot. Three-dimensional motion capture and force data were collected at preferred walking speed on an instrumented treadmill. Mechanical measures were subsequently assessed using a custom multi-segment foot model in Opensim. Factors with significant univariate associations were entered into multiple linear regression models to identify a group of factors independently associated with the mechanical measures. Results: Although no model could be created for any of the kinematic measures analysed, approximately 46% and 37% of the variance in the kinetic and energetic measures were associated with three or two factors respectively. Arch-height ratio, foot length and step width were associated with peak subtalar joint (STJ) moment, while greater STJ negative work was correlated to a low arch-height ratio and greater foot mobility. Conclusion: The models presented in this study suggest that the soft-tissue structures of a flat-arched, mobile foot are at a greater risk of injury as they have greater requirements to absorb energy and generate larger forces. However, as these associations are only moderate, other measures may also have an influence.
Article
Background: Altered hip and knee kinematics and joint coupling have been documented in runners with iliotibial band syndrome. Symptoms often present themselves after several minutes of running, yet the effect of fatigue warrants further exploration. The purpose of this study was to determine the effect of a run to fatigue in runners with iliotibial band syndrome, as compared to healthy controls. Methods: Twenty uninjured and 12 female runners with iliotibial band syndrome performed a treadmill run to fatigue. Prior-to and following a run to fatigue, overground running data were collected. Variables of interest included stance phase: peak hip adduction and internal rotation, peak hip abductor and external rotator joint moments and frontal-sagittal plane hip and knee joint coupling. Findings: Fatigue resulted in decreased peak hip adduction angles in injured runners. Fatigue did not affect injured runners differently than controls with respect to the remaining variables. Coupling differences did not exist between healthy and injured runners with respect to the loading or propulsive phases of stance. Interpretation: While clinicians often strengthen hip abductor muscles and provide gait re-training to decrease stance phase hip adduction, our results suggest that, when exerted, female runners with iliotibial band syndrome independently modify their running gait to decrease hip adduction, potentially as a result of pain. Fatigue did not have an effect on the remaining study variables. It is possible that reducing the length of the iliotibial band through minimizing hip adduction reduces pain, but the other variables examined are not sensitive to this phenomenon.
Chapter
Running continues to be one of the most common sports or activities for many regardless of age or experience. Despite the numerous benefits running offers, a large portion of runners will experience one or more running-related injuries, forcing some to substantially reduce their participation or stop altogether. Evaluating running mechanics can provide insights into the cause(s) of the injury and facilitate the injured runner to return to pre-injury levels of training. Video gait analysis is a clinically feasible and efficient approach to assess running mechanics and factors related to injury. Using high-speed video, specific body postures are identified in the frontal and sagittal planes of motion and used to estimate loads on individual joints and muscle groups. When combined with findings from the physical examination, a comprehensive rehabilitation plan can be formulated which may include modification to the running gait. To successfully conduct a video analysis of running, it is imperative that the clinician has a thorough understanding of running mechanics and specific body postures that are associated with injury and is effectively able to communicate this information to the runner.
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Article
Pathological mechanics are thought to play a role in many common running injuries. A review of the biomechanical literature reveals that a given running injury may be associated with multiple faulty running mechanics. Traditional rehabilitation programs have focused their efforts on addressing the injured anatomical structure. By focusing rehabilitation programs on correcting the pathomechanics of an injury, outcomes may be improved. Since the underlying faulty mechanics have been addressed, risk of reinjury may also be decreased. In this article, a pathomechanical paradigm for the treatment of the injured runner is introduced. Emphasis is placed on recognizing the most common types of faulty running mechanics often encountered in the clinical setting and their implications for injury. Finally, suggested treatment techniques are described.
Article
Patellofemoral pain (PFP) has often been attributed to abnormal hip and knee mechanics in females. To date, there have been few investigations of the hip and knee mechanics of males with PFP. The purpose of this study was to compare the lower extremity mechanics and alignment of male runners with PFP with healthy male runners and female runners with PFP. We hypothesized that males with PFP would move with greater varus knee mechanics compared with male controls and compared with females with PFP. Furthermore, it was hypothesized that males with PFP would demonstrate greater varus alignment. A gait and single-leg squat analysis was conducted on each group (18 runners per group). Measurement of each runner's tibial mechanical axis was also recorded. Motion data were processed using Visual 3D (C-Motion, Bethesda, MD). ANOVAs were used to analyze the data. Males with PFP ran and squatted in greater peak knee adduction and demonstrated greater peak knee external adduction moment compared with healthy male controls. In addition, males with PFP ran and squatted with less peak hip adduction and greater peak knee adduction compared with females with PFP. The static measure of mechanical axis of the tibial was not different between groups. However, a post hoc analysis revealed that males with PFP ran with greater peak tibial segmental adduction. Males with PFP demonstrated different mechanics during running and during a single-leg squat compared with females with PFP and with healthy males. Based upon the results of this study, therapies for PFP may need to be sex specific.
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Article
In 13 unloaded living knees we confirmed the findings previously obtained in the unloaded cadaver knee during flexion and external rotation/internal rotation using MRI. In seven loaded living knees with the subjects squatting, the relative tibiofemoral movements were similar to those in the unloaded knee except that the medial femoral condyle tended to move about 4 mm forwards with flexion. Four of the seven loaded knees were studied during flexion in external and internal rotation. As predicted, flexion (squatting) with the tibia in external rotation suppressed the internal rotation of the tibia which had been observed during unloaded flexion.
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Article
To provide an extensive and up to date database for specific running related injuries, across the sexes, as seen at a primary care sports medicine facility, and to assess the relative risk for individual injuries based on investigation of selected risk factors. Patient data were recorded by doctors at the Allan McGavin Sports Medicine Centre over a two year period. They included assessment of anthropometric, training, and biomechanical information. A model was constructed (with odds ratios and their 95% confidence intervals) of possible contributing factors using a dependent variable of runners with a specific injury and comparing them with a control group of runners who experienced a different injury. Variables included in the model were: height, weight, body mass index, age, activity history, weekly activity, history of injury, and calibre of runner. Most of the study group were women (54%). Some injuries occurred with a significantly higher frequency in one sex. Being less than 34 years old was reported as a risk factor across the sexes for patellofemoral pain syndrome, and in men for iliotibial band friction syndrome, patellar tendinopathy, and tibial stress syndrome. Being active for less than 8.5 years was positively associated with injury in both sexes for tibial stress syndrome; and women with a body mass index less than 21 kg/m(2) were at a significantly higher risk for tibial stress fractures and spinal injuries. Patellofemoral pain syndrome was the most common injury, followed by iliotibial band friction syndrome, plantar fasciitis, meniscal injuries of the knee, and tibial stress syndrome. Although various risk factors were shown to be positively associated with a risk for, or protection from, specific injuries, future research should include a non-injured control group and a more precise measure of weekly running distance and running experience to validate these results.
Article
There is little information on how a change in one feature of an individual’s running mechanics affects other aspects of running style. This study manipulated experimental conditions such that eight subjects ran with three different step lengths, three step widths, and three varying degrees of shoulder rotation. The effect of these changes on rearfoot pronation measures, step length, and step width were examined. Results showed that varying step length over a range of 18 cm and shoulder rotation over a range of 17° caused no significant differences in maximal pronation angle, total amount of pronation, or maximal pronation velocity. Varying step width from landing approximately 5 cm lateral to the midline to crossing over a midline by 2 cm increased the maximum pronation from 12.2 to 18.3°, the amount of pronation from 14.1 to 21.1°, and maximal pronation velocity from. 329°/s to 535°/s. It is suggested that runners with problems due to excessive pronation might try changing step width. Changes in step width and shoulder rotation had no significant effect on step length, and alterations to shoulder rotation did not affect step length or step width significantly. These results suggest that a runner attempts to maintain some aspects of running mechanics despite major alterations to other elements of running style.
Article
In walking, humans prefer a moderate step width that minimizes energetic cost and vary step width from step-to-step to maintain lateral balance. Arm swing also reduces energetic cost and improves lateral balance. In running, humans prefer a narrow step width that may present a challenge for maintaining lateral balance. However, arm swing in running may improve lateral balance and help reduce energetic cost. To understand the roles of step width and arm swing, we hypothesized that net metabolic power would be greater at step widths greater or less than preferred and when running without arm swing. We further hypothesized that step width variability (indicator of lateral balance) would be greater at step widths greater or less than preferred and when running without arm swing. Ten subjects ran (3m/s) at four target step widths (0%, 15%, 20%, and 25% leg length (LL)) with arm swing, at their preferred step width with arm swing, and at their preferred step width without arm swing. We measured metabolic power, step width, and step width variability. When subjects ran at target step widths less (0% LL) or greater (15%, 20%, and 25% LL) than preferred, both net metabolic power demand (by 3%, 9%, 12%, and 15%) and step width variability (by 7%, 33%, 46%, and 69%) increased. When running without arm swing, both net metabolic power demand (by 8%) and step width variability (by 9%) increased compared to running with arm swing. It appears that humans prefer to run with a narrow step width and swing their arms so as to minimize energetic cost and improve lateral balance.
Article
tibial stress fractures, which are among the most common running related injuries, have been associated with increased lower extremity loading (i.e., peak positive acceleration of the tibia, vertical force impact peak, and average and instantaneous vertical force loading rates) during initial contact. This study was conducted to evaluate the efficacy of a gait retraining program designed to reduce this loading during running and to assess the short-term persistence of these reductions. ten runners (six females and four males) with peak positive tibial acceleration greater than 8g, measured in an initial screening, participated in the retraining program. During the retraining sessions, subjects ran on a treadmill and received real-time visual feedback from an accelerometer attached to their distal tibias. Tibial acceleration and vertical ground reaction force data were collected from subjects during overground data collection sessions held pre-training, post-training, and at a 1-month follow-up. peak positive acceleration of the tibia, vertical force impact peak, and average and instantaneous vertical force loading rates were all reduced immediately following the gait retraining. The decrease in tibial acceleration was nearly 50%. The reductions in vertical force loading rates and vertical force impact peak were approximately 30% and 20%, respectively. These reductions were maintained at the 1-month follow-up. subjects were able to run with reduced tibial acceleration and vertical force loading immediately following completion of the gait retraining program and at the 1-month follow-up evaluation. This may reduce their risk of stress fractures.
Article
The fatigue life of bone is inversely related to strain magnitude. Decreasing stride length is a potential mechanism of strain reduction during running. If stride length is decreased, the number of loading cycles will increase for a given mileage. It is unclear if increased loading cycles are detrimental to skeletal health despite reductions in strain. To determine the effects of stride length and running mileage on the probability of tibial stress fracture. Ten male subjects ran overground at their preferred running velocity during two conditions: preferred stride length and 10% reduction in preferred stride length. Force platform and kinematic data were collected concurrently. A combination of experimental and musculoskeletal modeling techniques was used to determine joint contact forces acting on the distal tibia. Peak instantaneous joint contact forces served as inputs to a finite element model to estimate tibial strains during stance. Stress fracture probability for stride length conditions and three running mileages (3, 5, and 7 miles x d(-1)) were determined using a probabilistic model of bone damage, repair, and adaptation. Differences in stress fracture probability were compared between conditions using a 2 x 3 repeated-measures ANOVA. The main effects of stride length (P = 0.017) and running mileage (P = 0.001) were significant. Reducing stride length decreased the probability of stress fracture by 3% to 6%. Increasing running mileage increased the probability of stress fracture by 4% to 10%. Results suggest that strain magnitude plays a more important role in stress fracture development than the total number of loading cycles. Runners wishing to decrease their probability for tibial stress fracture may benefit from a 10% reduction in stride length.
Article
We have created a graphics-based software system that enables users to develop and analyze musculoskeletal models without programming. To define a model using this system one specifies the surfaces of the bones, the kinematics of the joints and the lines of action and force-generating parameters of the muscles. Once a model is defined, the function of each muscle can be analyzed by computing its length, moment arms, force and joint moments. The software has been implemented on a computer graphics workstation so that users can view the model from any perspective and graphically manipulate the joint kinematics and musculoskeletal geometry. Models can also be animated to visualize the results of motion analysis experiments. Since the software can be used to study models of many different musculoskeletal structures, it can enhance the productivity of investigators working on diverse problems in biomechanics.
Article
We propose a biomechanical model to explain the pathogenesis of iliotibial band friction syndrome in distance runners. The model is based on a kinematic study of nine runners with iliotibial band friction syndrome, a cadaveric study of 11 normal knees, and a literature review. Friction (or impingement) occurs near footstrike, predominantly in the foot contact phase, between the posterior edge of the iliotibial band and the underlying lateral femoral epicondyle. The study subjects had an average knee flexion angle of 21.4 degrees +/- 4.3 degrees at footstrike, with friction occurring at, or slightly below, the 30 degrees of flexion traditionally described in the literature. In the cadavers we examined, there was substantial variation in the width of the iliotibial bands. This variation may affect individual predisposition to iliotibial band friction syndrome. Downhill running predisposes the runner to iliotibial band friction syndrome because the knee flexion angle at footstrike is reduced. Sprinting and faster running on level ground are less likely to cause or aggravate iliotibial band friction syndrome because, at footstrike, the knee is flexed beyond the angles at which friction occurs.
Article
Motion at the midfoot joints can contribute significantly to overall foot motion during gait. However, there is little information regarding the kinematic coupling relationship at the midfoot. The purpose of the present study was to determine whether the coupling relationship at the midfoot and subtalar joints was affected when step width was manipulated during running. Twelve subjects ran over-ground at self-selected speeds using three different step widths (normal, wide, cross-over). Coupling at the midfoot (forefoot relative to rearfoot) and subtalar (rearfoot relative to shank) joints was assessed using cross-correlation techniques. Rearfoot kinematics were significantly different from normal running in cross-over running (P<0.05) but not in wide running. However, coupling between rearfoot eversion/inversion and shank rotation was consistently high (r>0.917), regardless of step width. This was also the case for coupling between rearfoot frontal plane motion and forefoot sagittal plane (r<-0.852) and forefoot transverse plane (r>0.946) motion. There was little evidence of coupling between rearfoot frontal plane motion and forefoot frontal plane motion in any of the conditions. Forefoot frontal plane motion appeared to have little effect on rearfoot frontal plane motion and thus, had no effect on motion at the subtalar joint. The strong coupling of forefoot sagittal and transverse plane motions with rearfoot frontal plane motion suggests that forefoot motion exerts an important influence on subtalar joint kinematics.
Article
Iliotibial band (ITB) syndrome is a common overuse injury in runners and cyclists. It is regarded as a friction syndrome where the ITB rubs against (and 'rolls over') the lateral femoral epicondyle. Here, we re-evaluate the clinical anatomy of the region to challenge the view that the ITB moves antero-posteriorly over the epicondyle. Gross anatomical and microscopical studies were conducted on the distal portion of the ITB in 15 cadavers. This was complemented by magnetic resonance (MR) imaging of six asymptomatic volunteers and studies of two athletes with acute ITB syndrome. In all cadavers, the ITB was anchored to the distal femur by fibrous strands, associated with a layer of richly innervated and vascularized fat. In no cadaver, volunteer or patient was a bursa seen. The MR scans showed that the ITB was compressed against the epicondyle at 30 degrees of knee flexion as a consequence of tibial internal rotation, but moved laterally in extension. MR signal changes in the patients with ITB syndrome were present in the region occupied by fat, deep to the ITB. The ITB is prevented from rolling over the epicondyle by its femoral anchorage and because it is a part of the fascia lata. We suggest that it creates the illusion of movement, because of changing tension in its anterior and posterior fibres during knee flexion. Thus, on anatomical grounds, ITB overuse injuries may be more likely to be associated with fat compression beneath the tract, rather than with repetitive friction as the knee flexes and extends.
Article
Iliotibial band (ITB) syndrome is regarded as an overuse injury, common in runners and cyclists. It is believed to be associated with excessive friction between the tract and the lateral femoral epicondyle-friction which 'inflames' the tract or a bursa. This article highlights evidence which challenges these views. Basic anatomical principles of the ITB have been overlooked: (a) it is not a discrete structure, but a thickened part of the fascia lata which envelops the thigh, (b) it is connected to the linea aspera by an intermuscular septum and to the supracondylar region of the femur (including the epicondyle) by coarse, fibrous bands (which are not pathological adhesions) that are clearly visible by dissection or MRI and (c) a bursa is rarely present-but may be mistaken for the lateral recess of the knee. We would thus suggest that the ITB cannot create frictional forces by moving forwards and backwards over the epicondyle during flexion and extension of the knee. The perception of movement of the ITB across the epicondyle is an illusion because of changing tension in its anterior and posterior fibres. Nevertheless, slight medial-lateral movement is possible and we propose that ITB syndrome is caused by increased compression of a highly vascularised and innervated layer of fat and loose connective tissue that separates the ITB from the epicondyle. Our view is that ITB syndrome is related to impaired function of the hip musculature and that its resolution can only be properly achieved when the biomechanics of hip muscle function are properly addressed.
Article
Injury patterns in distance running may be related to kinematic adjustments induced by fatigue. The goal was to measure changes in lower extremity mechanics during an exhaustive run in individuals with and without a history of iliotibial band syndrome (ITBS). Sixteen recreational runners ran to voluntary exhaustion on a treadmill at a self-selected pace. Eight runners had a history of ITBS. Twenty-three reflective marker positions were recorded by an eight-camera 120 Hz motion capture system. Joint angles during stance phase were exported to a musculoskeletal model (SIMM) with the iliotibial band (ITB) modeled as a passive structure to estimate strain in the ITB. For ITBS runners, at the end of the run: (1) knee flexion at heel-strike was higher than control (20.6 degrees versus 15.3 degrees, p=0.01); (2) the number of knees with predicted ITB impingment upon the lateral femoral epicondyle increased from 6 to 11. Strain in the ITB was higher in the ITBS runners throughout all of stance. Maximum foot adduction in the ITBS runners was higher versus control at the start of the run (p=0.003). Maximum foot inversion (p=0.03) and maximum knee internal rotation velocity (p=0.02) were higher versus control at the end of the run. In conclusion, ITB mechanics appear to be related to changes in knee flexion at heel-strike and internal rotation of the leg. These observations may suggest kinematic discriminators for clinical assessment.
Article
Iliotibial band syndrome is the leading cause of lateral knee pain in runners. Despite its high prevalence, little is known about the biomechanics that lead to this syndrome. The purpose of this study was to prospectively compare lower extremity kinematics and kinetics between a group of female runners who develop iliotibial band syndrome compared to healthy controls. It was hypothesized that runners who develop iliotibial band syndrome will exhibit greater peak hip adduction, knee internal rotation, rearfoot eversion and no difference in knee flexion at heel strike. Additionally, the iliotibial band syndrome group were expected to have greater hip abduction, knee external rotation, and rearfoot inversion moments. A group of healthy female recreational runners underwent an instrumented gait analysis and were then followed for two years. Eighteen runners developed iliotibial band syndrome. Their initial running mechanics were compared to a group of age and mileage matched controls with no history of knee or hip pain. Comparisons of peak hip, knee, rearfoot angles and moments were made during the stance phase of running. Variables of interest were averaged over the five running trials, and then averaged across groups. The iliotibial band syndrome group exhibited significantly greater hip adduction and knee internal rotation. However, rearfoot eversion and knee flexion were similar between groups. There were no differences in moments between groups. The development of iliotibial band syndrome appears to be related to increased peak hip adduction and knee internal rotation. These combined motions may increase iliotibial band strain causing it to compress against the lateral femoral condyle. These data suggest that treatment interventions should focus on controlling these secondary plane movements through strengthening, stretching and neuromuscular re-education.
Article
Iliotibial band syndrome is the leading cause of lateral knee pain in runners. It is thought that pain develops from strain on the iliotibial band due to friction of the iliotibial band sliding over the lateral femoral epicondyle. The purpose of this study was to investigate mechanical strain in the iliotibial band as a possible causative factor in the development of iliotibial band syndrome. From a large prospective study, female runners who incurred iliotibial band syndrome during the study were compared to a control group who incurred no injuries. Strain, strain rate and duration of impingement were determined from a musculoskeletal model of the lower extremity. The results indicated that the iliotibial band syndrome subjects exhibited greater strain throughout the support period, but particularly at midsupport compared to the control group. Strain rate was significantly greater in the iliotibial band syndrome group compared to the control group and was greater in the involved limb of the iliotibial band syndrome group compared to their contralateral limb. However, there were no differences in the duration of impingement between the groups. This study indicates that a major factor in the development of iliotibial band syndrome is strain rate. Therefore, we suggest that strain rate, rather than the magnitude of strain, may be a causative factor in developing iliotibial band syndrome. The effect size (>0.5) indicated that strain rate may be biologically significant in the etiology of iliotibial band syndrome.