OBJECTIVES:Strategies to reduce Achilles tendon forces during running may be beneficial for injury prevention. Increasing ground contact time could reduce Achilles tendon forces during running but may also elicit changes in cadence that could offset these reductions. The purpose of this study was to determine if changing ground contact time altered Achilles tendon forces during running, with both a fixed and a free cadence. DESIGN:This was a cross-sectional study of healthy rearfoot strike runners. METHODS:Thirty rearfoot strike runners ran on a concrete sidewalk at 3.0 m/s with preferred, low, and high ground contact times, with both a fixed and a free cadence. Achilles tendon forces were estimated using data collected from Loadsol insoles. RESULTS:Peak Achilles tendon force, cumulative Achilles tendon fatigue load, and Achilles tendon impulse were compared among ground contact time and cadence conditions. Peak Achilles tendon force and cumulative Achilles tendon fatigue load decreased as ground contact time increased. These changes occurred with both a fixed and a free cadence. CONCLUSIONS:Increasing ground contact time may be a viable intervention for decreasing peak Achilles tendon force and cumulative Achilles tendon fatigue load in runners, without the need for additional instructions to control cadence.

Force sensing insoles for measuring vertical ground reaction force (VGRF) have several advantages over laboratory-based force plates. Data can easily be collected in real-world environments and long duration trials with multiple steps are feasible. However, the sampling rate of insoles is lower and only vertical force is recorded. The reliability and validity of Loadsol® force sensing insoles have been evaluated for treadmill walking, but not overground walking. The purpose of the study was to determine criterion-related validity and test-retest reliability of Loadsol® compared to gold standard force plates. Twenty healthy young adults walked overground across force plates while wearing insoles for two blocks of five trials. Variables of interest were extracted from each trial and averaged across trials and participants. Intraclass correlation coefficients (ICCs) determined criterion-related validity for Loadsol® variables compared to force plate variables. ICCs also determined within session test-retest reliability for Loadsol® and force plates. Bland Altman plots were generated to assess bias and 95% limits of agreement. Additionally, standard error of measurements (SEMs) and minimum detectable differences (MDDs) were calculated. Excellent validity and minimal bias with Loadsol® was found for passive peak, active peak, instantaneous loading rate, impulse, and stance time, with good validity and an overestimation bias for average loading rate. Excellent test-retest reliability comparable to force plate reliability was also found for all variables. The SEMs and MDDs reported here help to inform researchers about whether the Loadsol® are suited to answering their research questions. By comparing the anticipated changes in a VGRF variable with the MDD of that variable, researchers can determine if Loadsol® are appropriate for the context of their study.

BACKGROUND:Two biomechanical mechanisms for the development of Achilles tendinopathy in runners have been proposed: A whipping mechanism characterized by prolonged and excessive rearfoot eversion, and a tearing mechanism characterized by high eccentric plantar flexor forces. The purpose of this pilot study was to determine if runners with and without a history of Achilles tendinopathy exhibited gait biomechanics consistent with either of these mechanisms. METHODS:Seven male runners with previous or current Achilles tendinopathy and seven healthy male control runners were evaluated by three-dimensional gait analysis. Peak rearfoot eversion angle, rearfoot eversion excursion, duration of rearfoot eversion, and peak rearfoot inversion angle were compared between groups to evaluate the whipping mechanism of injury. Peak dorsiflexion angle, peak dorsiflexion velocity, and peak ankle power absorption were compared between groups to evaluate the tearing mechanism. Additionally, rearfoot eversion angle and sagittal plane ankle power waveforms were compared between groups using statistical parametric mapping. FINDINGS:There were no differences in any rearfoot eversion, inversion, or dorsiflexion variables or waveforms during running in the Achilles tendinopathy group compared to controls. INTERPRETATION:Rearfoot strike runners with Achilles tendinopathy do not exhibit running biomechanics consistent with either the whipping or tearing mechanisms of injury.

Field-based tibial acceleration measurements are increasingly common but sampling frequencies vary between accelerometers. The purpose of this study was to determine the minimum sampling frequency needed for reliable and accurate measurement of peak axial and resultant tibial acceleration during running in the field. Tibial acceleration was measured at 7161 Hz in 19 healthy runners on concrete and grass. Acceleration data were down sampled to approximate previously used sampling frequencies. Peak axial and resultant tibial acceleration were calculated for each sampling frequency. The within-session reliability and accuracy of peak axial and resultant tibial accelerations were evaluated using intraclass correlation coefficients, mean differences, and 95% limits of agreements. Intraclass correlation coefficients greater than .9 indicated excellent within-session reliability for both peak axial and resultant tibial acceleration measured while running on concrete and grass. Peak axial and resultant tibial accelerations were 0.5 to 1.4 g lower and minimal detectable differences were up to 0.6 g higher at 102 Hz compared with higher sampling frequencies. We recommend a minimum sampling frequency of 199 Hz for accurate and reliable measurements of peak axial and resultant tibial acceleration in the field.

Achilles tendinopathy is a common running injury and high Achilles tendon forces may play a role in its etiology. Identifying biomechanical variables that contribute to high Achilles tendon forces may help prevent injuries. PURPOSE: To identify gait features that distinguish between runners with high and low peak Achilles tendon forces. METHODS: This was a secondary analysis of biomechanical data from 60 female rearfoot strike runners. We identified tertiles of runners with the highest and lowest peak Achilles tendon forces. Peak Achilles tendon force, sagittal plane angles, center of pressure and ground reaction force waveforms were extracted and put into a principal components analysis. Retained principal components were then put into a discriminant analysis. Reconstructed waveforms and percent variance explained were used to interpret gait features that distinguished between runners with high and low Achilles tendon forces. RESULTS: Runners with high peak Achilles tendon forces had a higher center of pressure velocity at the beginning of stance, increasing ground reaction force moment arm at midstance; more dorsiflexion excursion at midstance, decreasing Achilles tendon moment arm at midstance; and higher ground reaction forces throughout stance compared to runners with low peak Achilles tendon forces. CONCLUSION: These differences collectively serve to increase peak Achilles tendon force needed to generate the sagittal plane ankle moment. Interventions that target midstance dorsiflexion and center of pressure progression may be useful for decreasing peak Achilles tendon forces during running. Table 1. Percent variance explained and percent of waveforms adequately reconstructed for all retained principal components. P-values are for independent samples t-tests comparing high and low peak Achilles tendon force groups. - Waveform % Reconstructed Waveforms < Q-critical Principal Component # % Variance Explained p-value Sagittal Plane Ankle Angle 98% 1 74.6 0.015 2 17.8 0.006 Sagittal Plane Knee Angle 88% 1 80.2 0.649 2 13.9 0.204 Sagittal Plane Hip Angle 85% 1 81.0 0.366 2 9.3 0.193 Anterior/Posterior Center of Pressure Position 100% 1 56.8 0.537 2 28.9 0.0496 3 8.2 0.663 2D Resultant Ground Reaction Force 100% 1 79.5 0.029 2 11.0 0.566 This project was funded by a Drexel University College of Nursing and Health Professions Dean’s PhD Student Research Award.

INTRODUCTION:Patellofemoral pain (PFP) is a common overuse injury associated with physical activity, including walking. The risk for PFP may increase if walking biomechanics change during a bout of walking. Because walking for exercise is often recommended to previously sedentary adults, this would be a cause for concern. The purpose of this study was to determine any differences in walking biomechanics associated with PFP between sedentary and active young women initially and after 30 min of walking for exercise. METHODS:Fifteen sedentary and 15 active young women walked overground for five trials of three-dimensional gait analysis before and after a 30-min treadmill walk. Peak knee flexion angle and extensor moment were compared between groups and before and after the 30-min walk. RESULTS:Comparing groups at baseline, peak knee flexion angle and peak knee extensor moment were not statistically significantly different between groups. After the 30-min walk, peak knee flexion angle and extensor moment increased slightly in both groups. CONCLUSIONS:Smaller, not larger, peak knee flexion angle and extensor moment during walking have been associated with increased risk of PFP. Therefore, sedentary and active young women can walk for 30 min without further detrimental changes to walking biomechanics that may increase their risk of PFP.

Background:Tibial stress fracture（TSF） is an overuse running injury with a long recovery period.While many running studies refer to biomechanical risk factors for TSF,only a few have compared biomechanics in runners with TSF to controls.The aim of this systematic review and meta-analysis was to evaluate biomechanics in runners with TSF compared to controls.Methods:Electronic databases PubMed,Web of Science,SPORTDiscus,Scopus,Cochrane,and CINAHL were searched.Risk of bias was assessed and meta-analysis conducted for variables reported in 3 or more studies.Results:The search retrieved 359 unique records,but only the 14 that compared runners with TSF to controls were included in the review.Most studies were retrospective,2 were prospective,and most had a small sample size（5-30 per group）.Many variables were not significantly different between groups.Meta-analysis of peak impact,active,and braking ground reaction forces found no significant differences between groups.Individual studies found larger tibial peak anterior tensile stress,peak posterior compressive stress,peak axial acceleration,peak rearfoot eversion,and hip adduction in the TSF group.Conclusion:Meta-analysis indicated that discrete ground reaction force variables were not statistically significantly different in runners with TSF compared to controls.In individual included studies,many biomechanical variables were not statistically significantly different between groups.However,many were reported by only a single study,and sample sizes were small.We encourage additional studies with larger sample sizes of runners with TSF and controls and adequate statistical power to confirm or refute these findings.

External load variables such as peak tibial acceleration (PTA), peak vertical ground reaction forces (GRF) and its instantaneous vertical loading rate (IVLR) may contribute to running injuries although evidence is conflicting given the influence of training load and tissue health on injuries. These variables are influenced by footwear, speed, surface and foot strike pattern during running. The purpose of this study was to assess the influence of four surfaces and two running speeds on external load variables in rearfoot strike (RFS) runners. Twelve RFS runners (confirmed with sagittal foot contact angle) completed a 2-min running bout on a treadmill and 50-m running bouts over the three surfaces (pavement, rubber track and grass) in standardised shoes at their preferred speed and 20% faster. PTA and vertical GRFs were collected using inertial measurement units and in-shoe force insoles. No interaction or surface effects were observed (p > 0.017). The faster speed produced greater axial PTA (+19.2%; p < 0.001), resultant PTA (+20.7%; p < 0.001), peak vertical GRF (+6.6%; p = 0.002) and IVLR (+16.5%; p < 0.001). These findings suggest that surface type does not influence PTA, peak vertical GRF and IVLR but that running faster increases the magnitude of these external loads regardless of surface type in RFS runners.

Differences in walking biomechanics between groups or conditions should be greater than the measurement error to be considered meaningful. Reliability and minimum detectable differences (MDDs) have not been determined for lower-extremity angles and moments during walking within a session, as needed for interpreting differences in cross-sectional studies. Thus, the purpose of this study was to determine within-session reliability and MDDs for peak ankle, knee, and hip angles and moments during walking. Three-dimensional gait analysis was used to record walking at 1.25 m/s (±5%) in 18 men, 18-50 years of age. Peak angles and moments were calculated for 2 sets of 3 trials. Intraclass correlation coefficients (3, 3) were used to determine within-session reliability. In addition, MDDs were calculated. Within-session reliability was good to excellent for all variables. The MDDs ranged from 0.9° to 3.6° for joint angles and 0.06 to 0.15 N·m/kg for joint moments. Within-session reliability for peak ankle, knee, and hip angles and moments was better than the between-session reliability reported previously. Overall, our MDDs were similar or smaller than those previously reported for between-session reliability. The authors recommend using these MDDs to aid in the interpretation of cross-sectional comparisons of lower-extremity biomechanics during walking in healthy men.

In running assessments, biomechanics of the stance phase are often measured to understand external loads applied to the body. Identifying time of initial foot contact can be challenging in runners with different strike patterns. Peak downward velocity of the pelvis (PDVP) has been validated in a laboratory setting to detect initial contact. Inertial measurement units (IMUs) allow measurements of kinematic variables outside laboratory settings. The aim of this study was to validate the PDVP method using an inertial and optical motion capture system to detect initial contact at different speeds and foot strike patterns compared to the force sensing criterion. Twenty healthy runners ran for two minutes at 11, 13, and 15 km/h on a force-instrumented treadmill. 3D kinematics were obtained from an optical motion capture system and an 8-sensor inertial system. A generalized estimating equation showed no effect of footstrike pattern on the time difference (offset) between initial contact based on an inertial or optical system and the force sensing criterion. There was a significant main effect of speed on offset, in which offsets decreased with higher speeds. There was no interaction effect of speed and foot strike pattern on the offsets. Offsets ranged from 21.7 +/- 0.2 ms for subjects running at 15 km/h (inertial versus force sensing criterion) to 27.2 +/- 0.1 ms for subjects running at 11 km/h (optical versus force sensing criterion). These findings support the validity of the PDVP method obtained from optical and inertial systems to detect initial contact in different footstrike patterns and at different running speeds. (C) 2021 The Author(s). Published by Elsevier Ltd.

The gene encoding N-benzyl-3-pyrrolidinol dehydrogenase (DDBJ/EMBL/GenBank accession no. AB294179), a useful biocatalyst for producing (S)-N-benzyl-3-pyrrolidinol, was cloned from the genomic DNA of Geotrichum capitatum JCM 3908. The gene contained an open reading frame consisting of 1023 nucleotides corresponding to 340 amino acid residues. The subunit molecular weight was calculated to be 39,000. The predicted amino acid sequence did not have significant similarity to those of N-benzyl-3-pyrrolidinone reductases reported previously. From 30 mM N-benzyl-3-pyrrolidinone, (S)-N-benzyl-3-pyrrolidinol was obtained with a yield >99.9% and an enantiomeric excess >99.9% in 1-h and 2-h reactions without NADH addition by the resting cells of Escherichia coli HB 101 strains harboring the expression plasmids pSG-POBS and pSF-POBS that possess the glucose dehydrogenase gene and formate dehydrogenase gene as an NADH-reproducing system, respectively, besides the N-benzyl-3-pyrrolidinol dehydrogenase gene. N-Benzyl-3-pyrrolidinol dehydrogenase activity (0.56 U/mg) was observed in E. coli (pSG-POBS), which was 17-fold the specific activity observed in G. capitatum JCM 3908.

With wearable technology becoming more popular, more companies are creating sensors to assess biomechanical parameters including peak tibial acceleration (PTA) during running. However, validity of data from wearable technology relative to “gold-standard” research-grade instruments is highly important. PURPOSE: Assess the difference in PTA obtained from wearable inertial measurement units (IMU) and a research-grade accelerometer at different running speeds. METHODS: Six participants completed 1-2min treadmill running bouts at 3.0 m/s and 4.0 m/s while wearing standardized footwear (1080, New Balance). A research-grade tri-axial accelerometer (ACC; 1200Hz, model 356A26, PCB Piezotronics) and a 9-axis IMU (1000Hz, Blue Trident, IMeasureU) were secured to the distal tibia to capture PTA during running. The testing at both speeds was completed with the ACC below and above the IMU to account for possible position effects. Data were collected for the final 15 seconds of each running bout and the average of both positions for 10-15 peaks of axial tibial acceleration were used for analyses. Paired t-tests and Cohen’s d effect sizes were calculated to compare instrument PTA means at different speeds. RESULTS: At 3.0 m/s, mean PTA was not different between ACC (5.2±1.9 G) and IMU (5.9±2.2 G; p = 0.33; d = 0.34). At 4.0 m/s, mean PTA was not different between ACC (8.5±3.7 G) and IMU (9.8±4.2 G; p = 0.33; d = 0.33). Figure 1 demonstrates the individual variability in the difference in PTA obtained from the ACC and IMU at different speeds (A) and different positions (B). CONCLUSION: Despite the statistically similar PTA means obtained from both instruments, the difference in PTA between ACC and IMU appears to be highly variable among individuals. This variability in PTA may be due to differences between devices, device placement, attachment method, or individual running style. This highlights the difficulty in controlling sources of variability during testing.

Achilles tendinopathy is a common running injury that affects up to 13% of runners. A “whipping” mechanism, in which abnormal rearfoot eversion causes asymmetrical loading of the tendon, has been proposed for the development of Achilles tendinopathy in runners. A second “tearing” mechanism, in which eccentric plantar flexor contractions cause microtears in the Achilles tendon, has also been proposed. However, a clear link between these mechanisms and Achilles tendinopathy has not been demonstrated. PURPOSE: To determine if peak rearfoot eversion, duration of rearfoot eversion, peak sagittal plane ankle power absorption, and peak dorsiflexion moment are different between runners with and without a history of Achilles tendinopathy. METHODS: 10 male, rearfoot strike runners (34±10 years; 1.79 ± 0.07 m; 81.3 ± 12.6 kg) participated. Five participants had previous or current Achilles tendinopathy and five had no history of Achilles tendon pain. Reflective markers were placed on the trunk, pelvis, legs, and feet. A motion capture system recorded five good trials for each participant running at 3.7 m/s. Variables of interest and effect sizes (r) were calculated to compare groups. RESULTS: There was a small effect for peak rearfoot eversion, with previously injured runners exhibiting higher peak rearfoot eversion angles (Table 1). There was also a small effect for the duration of rearfoot eversion, with injured runners remaining in an everted position for longer than the control group. There were no differences between groups in peak power absorption or peak dorsiflexion moment. CONCLUSION: In this preliminary study runners with and without Achilles tendinopathy exhibited gait characteristics that provide partial support for the whipping mechanism of injury proposed for Achilles tendinopathy in runners. However, these findings were not consistent with the proposed tearing mechanism of injury.

A large peak hip adduction angle during running is a risk factor for several overuse injuries in women. The purpose of this study was to determine if female runners with a large peak hip adduction angle have differences in eccentric hip abductor muscle strength, hip neuromuscular control, and/or hip width to femoral length ratio (HW:FL) compared to those with a small angle. Hip adduction during running, hip strength, hip control, and HW:FL were measured in sixty healthy female runners (1.66 +/- 0.06 m; 63.2 +/- 8.3 kg; 27 +/- 6 years). Data from twenty runners with the largest and twenty with the smallest peak hip adduction angles were analysed. Between-group differences in hip strength, control, and HW:FL were determined using independent t-tests (p < 0.05). Variables that were significantly different between groups were entered into a regression model. Runners in both groups had similar hip strength (p = 0.90) and control (p = 0.65). HW:FL was greater in the large peak angle group (p = 0.04), but only explained a small amount of peak hip adduction angle variance for all sixty runners (R-2 = 0.05). Alarge peak hip adduction angle in some healthy female runners may simply be instinctive as there were no deficiencies in the strength or neuromuscular control constructs assessed.

High tibial acceleration peaks have been associated with tibial stress fracture in runners. Field-testing with wearable wireless accelerometers in now commonplace, but some devices have a lower sampling frequency than in laboratory testing. PURPOSE: To determine the influence of sampling rate on peak axial tibial acceleration and peak resultant tibial acceleration magnitude during running. METHODS: As part of a larger study, 19 healthy adults were recruited (10 women; 31±6 years; 1.70±0.08 m; 68.6±11.6 kg) and provided informed consent to participate. A precision accelerometer sampling at 1000Hz was attached to the distal anteromedial aspect of the right tibia. Participants ran at 3.0m/s in the laboratory for five good trials making contact with a force plate sampling at 1000Hz. Raw data were down-sampled to 500Hz and 100Hz, common sampling rates for wearable wireless accelerometers. All data were low-pass filtered at 70Hz. Stance phase was identified by foot contact on the force plate. Peak positive axial acceleration and peak resultant acceleration were determined for each trial and averaged. One factor repeated measures analysis of variance with least significant difference post-hoc tests determined whether peaks differed among sampling rates. Effect sizes were calculated to aid interpretation of the data. RESULTS: Both peak axial and peak resultant acceleration were significantly reduced when tibial acceleration was sampled at 100Hz compared to 500Hz or 1000Hz (p = 0.041). Reductions were 0.7g or about 10% of the peak magnitude at 1000Hz, a small effect. Values were stable between the 500Hz and 1000Hz sampling rates. CONCLUSION: We recommend that tibial acceleration data are sampled at rates of 500Hz or greater to avoid attenuation of peaks producing erroneously low values for both peak axial and peak resultant acceleration.Table: Mean and standard deviation of peak axial and peak resultant tibial acceleration during running when sampling data at different rates

Hip abductor muscle strengthening is often prescribed to reduce the peak hip adduction angle in runners with overuse knee injury. However, no evidence exists associating greater isometric hip abductor muscle strength with smaller peak hip adduction angle during running. Beyond muscle strength, muscle activation patterns may play an important role in controlling joint movement during running. Therefore, the purpose of this investigation was to determine if associations existed among hip adduction angle, hip abductor muscle activity, and isometric hip abductor muscle strength. Twenty-five currently healthy female runners participated. Average gluteus medius muscle activity and tensor fascia lata muscle activity were determined during hip abductor maximal voluntary isometric contractions. Three-dimensional kinematics and hip abductor muscle activity were collected during treadmill running. Dependent variables were analyzed via Pearson product moment correlations. Multi-variable linear regression determined muscle activity's and strength's contributions to the peak hip adduction angle. A fair positive correlation was observed between the peak hip adduction angle and average tensor fascia lata muscle activity magnitude. Additionally, there was a moderate negative correlation between isometric hip abductor muscle strength and average gluteus medius muscle activity magnitude. Tensor fascia lata activity magnitude accounted for the most variance of the peak hip adduction angle. This study adds to the literature which indicates a lack of association between isometric hip abductor muscle strength and peak hip adduction angle in healthy runners. Factors other than hip abductor muscle strength and activation may account for more of the variance in peak hip adduction angles among runners.

The analysis of in-field biomechanics data typically requires the identification of foot contact. Existing techniques to identify foot contact using accelerometers offer a viable option for identifying foot contact in the field. However, these techniques often require the placement of additional accelerometers or the identification of impact peaks, which can be difficult when peaks are low. Using resultant tibial acceleration to identify foot contact may overcome these limitations. The purpose of this study was to develop a new technique for identifying time of foot contact during rearfoot strike running from a single triaxial accelerometer placed on the distal tibia. Additionally, we sought to establish the concurrent validity of this new technique. An algorithm to identify foot contact from a local minimum in the resultant tibial acceleration waveform was developed and tested in nineteen rearfoot strike runners. Foot contact determined from the resultant tibial acceleration occurred 2.3 +/- 4.7 ms earlier than foot contact determined from vertical ground reaction force, with 95% limits of agreement of -6.8 to 11.5 ms. The difference between the two methods was less than 10 ms for 183 out of 190 foot contacts. These findings compare favorably to previous techniques for identifying foot contact using accelerometers. Additionally, this technique can also be used when peak tibial accelerations are low. We recommend this technique to identify foot contacts in the field, particularly when some peak values are expected to be low. (C) 2020 Elsevier Ltd. All rights reserved.

Measurements of tibial acceleration during running must be reliable to ensure valid results and reduce errors. The purpose of this study was to determine the reliability and minimal detectable difference (MDD) of peak axial and peak resultant tibial acceleration during overground and treadmill running. The authors also compared reliability and MDDs when peak tibial accelerations were determined by averaging 5 or 10 trials. Tibial acceleration was measured during overground and treadmill running of 19 participants using a lightweight accelerometer mounted to the tibia. Peak axial and peak resultant tibial accelerations were determined for each trial. Intraclass correlation coefficients determined within-session reliability, and MDDs were also calculated. Within-session reliability was excellent for all conditions (intraclass correlation coefficients = .95-.99). The MDDs ranged from 0.6 to 1.4 g for peak axial acceleration and from 1.6 to 2.0 g for peak resultant acceleration and were lowest for peak axial tibial acceleration during overground running. Averaging 10 trials did not improve reliability compared to averaging 5 trials but did result in small reductions in MDDs. For peak axial tibial acceleration only, lower MDDs indicate that overground running may be the better option for detecting small differences.

BACKGROUND:Atypical 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 QUESTION:Do 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?METHODS:Thirty 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.RESULTS:Hip 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.SIGNIFICANCE:These 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.