Influence of Step Rate on Shin Injury and Anterior Knee Pain in High School Runners

Acute changes in sagittal plane kinematics while wearing a novel belt device during treadmill running

Somatosensory feedback is used in walking retraining; however, its utility in running is less feasible due to the greater associated speeds. The purpose of this study was to examine the acute effects of wearing a novel running belt device on sagittal plane running kinematics. Ten healthy runners ran on a treadmill with and without the use of a running belt device within a repeated measures study design. Temporal-spatial characteristics and sagittal plane knee and ankle kinematics were recorded with three-dimensional motion analysis. Wilcoxon Signed-Rank Tests revealed significant decreases in centre of mass vertical displacement (z = -2.083, p = 0.003), tibial inclination at initial contact (z = -2.803, p = 0.003), and stance phase knee joint excursion (z = -2.701, p = 0.003), and greater knee flexion at initial contact (z = -2.803, p = 0.003) when the belt was donned. No differences were observed in step rate (z = -0.351, p = 0.363), foot inclination angle at initial contact (z = -2.090, p = 0.018), or peak knee flexion during stance (z = -1.172, p = 0.121). Findings suggest that donning a running belt can minimise specific high-risk biomechanical characteristics in runners with particular kinematic profiles.

How Do Spatiotemporal Parameters and Lower-Body Stiffness Change with Increased Running Velocity? A Comparison Between Novice and Elite Level Runners

This study aimed to examine the effect of running velocity on spatiotemporal parameters and lower-body stiffness of endurance runners, and the influence of the performance level on those adaptations. Twenty-two male runners (novice [NR], n = 12, and elite runners [ER], n = 10) performed an incremental running test with a total of 5 different running velocities (10, 12, 14, 16, 18 km/h). Each condition lasted 1 min (30 s acclimatization period, and 30 s recording period). Spatiotemporal parameters were measured using the OptoGait system. Vertical (Kvert) and leg (Kleg) stiffness were calculated according to the sine-wave method. A repeated measures ANOVA (2 x 5, group x velocities) revealed significant adaptations (p < 0.05) to increased velocity in all spatiotemporal parameters and Kvert in both NR and ER. ER showed a greater flight time (FT) and step angle (at 18 km/h) (p < 0.05), longer step length (SL) and lower step frequency (SF) (p < 0.05), whereas no between-group differences were found in contact time (CT) nor in the sub-phases during CT at any speed (p ≥ 0.05). ER also showed lower Kvert values at every running velocity (p < 0.05), and no differences in Kleg (p ≥ 0.05). In conclusion, lower SF and Kvert and, thereby, longer FT and SL, seem to be the main spatiotemporal characteristics of high-level runners compared to their low-level counterparts.

Association Between Temporal Spatial Parameters and Overuse Injury History in Runners: A Systematic Review and Meta-analysis

BACKGROUND

Temporal spatial parameters during running are measurable outside of clinical and laboratory environments using wearable technology. Data from wearable technology may be useful for injury prevention, however the association of temporal spatial parameters with overuse injury in runners remains unclear.

OBJECTIVE

To identify the association between overuse injury and temporal spatial parameters during running.

DATA SOURCES

Electronic databases were searched using keywords related to temporal spatial parameters, running, and overuse injury, and authors' personal article collections through hand search.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Articles included in this systematic review contained original data, and analytically compared at least one temporal spatial parameter (e.g. cadence) between uninjured and retrospectively or prospectively injured groups of runners. Articles were excluded from this review if they did not meet these criteria or measured temporal spatial parameters via survey.

STUDY APPRAISAL AND SYNTHESIS METHOD

The internal validity of each article was assessed using the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Meta-analyses were conducted for temporal spatial parameters if data existed from at least three separate cohorts of the same prospective or retrospective design. Data were pooled and analyzed using an inverse variance fixed-effect model.

RESULTS

Thirteen articles which tested a total of 24 temporal spatial parameters during running were included in the review. Meta-analyses were conducted on four temporal spatial parameters using data from eleven retrospective studies. Healthy runners and those with a history of overuse injury had a similar average stride time (mean difference: 0.00 s, 95% CI - 0.01 to 0.01 s), contact time (mean difference: 0.00 s, 95% CI 0.00 to 0.01 s), cadence (mean difference: 0.3 steps per minute (spm), 95% CI - 1.8 to 2.5 spm), and stride length (mean difference 0.00 m, 95% CI - 0.05 to 0.05 m) during running.

LIMITATIONS

Data pooled for meta-analyses were limited to retrospective design studies. Studies included in the systematic review had low methodological consistency.

CONCLUSION

Based on pooled results from multiple studies, stride time, contact time, cadence, and stride length averages are not distinguishable between runners either with or without a history of overuse injury. More prospective studies are required to determine the association of temporal spatial parameters with overuse injury development in runners.

SYSTEMATIC REVIEW REGISTRATION REGISTRY AND NUMBER

CRD42018112290.

Immediate effect of visual, auditory and combined feedback on foot strike pattern

BACKGROUND

A growing body of literature supports the promising effect of real-time feedback to re-train runners. However, no studies have comprehensively assessed the effects of foots trike and cadence modification using different forms of real-time feedback provided via wearable devices.

RESEARCH QUESTION

The purpose of the present study was to determine if a change could be made in foot strike pattern and plantar loads using real-time visual, auditory and combined feedback provided using wearable devices.

METHODS

Visual, auditory and combined feedback were provided using wearable devices as fifteen recreational runners ran on a treadmill at self-selected speed and increased cadence. Plantar loads and location of initial contact were measured with a flexible insole system. Repeated measures ANOVAs with Bonferroni adjusted pair-wise comparisons were used to assess statistical significance.

RESULTS AND SIGNIFICANCE

A significant effect of condition was noted on location of center of pressure (p < 0.01). Bonferroni-adjusted post-hoc comparisons showed that feedback conditions differed from baseline as well as the new cadence conditions, however did not differ from each other. A significant interaction effect (region x feedback) was found for plantar loads (maximum force P < 0.001). Significant effects of feedback were noted at the heel (P < 0.001), medial midfoot (P < 0.001), lateral midfoot (P < 0.001), medial forefoot (P = 0.003), central forefoot (P = 0.003), and great toe (P = 0.004) but not at the lateral forefoot (P = 0.6) or lateral toes (P = 0.507).

SIGNIFICANCE

The unique findings of our study showed that an anterior shift of the center of pressure, particularly when foot strike modification was combined with 10% increased cadence. We found lower heel and midfoot loads along with higher forefoot and great toe loads when foot strike modification using real-time feedback was combined with increased cadence. Our findings also suggest that auditory feedback might be more effective than visual feedback in foot-strike modification.

Agreement between the spatiotemporal gait parameters from two different wearable devices and high-speed video analysis

This study aimed to evaluate the concurrent validity of two different inertial measurement units for measuring spatiotemporal parameters during running on a treadmill, by comparing data with a high-speed video analysis (VA) at 1,000 Hz. Forty-nine endurance runners performed a running protocol on a treadmill at comfortable velocity (i.e., 3.25 ± 0.36 m.s^-1). Those wearable devices (i.e., Stryd™ and RunScribe™ systems) were compared to a high-speed VA, as a reference system for measuring spatiotemporal parameters (i.e. contact time [CT], flight time [FT], step frequency [SF] and step length [SL]) during running at comfortable velocity. The pairwise comparison revealed that the Stryd™ system underestimated CT (5.2%, p < 0.001) and overestimated FT (15.1%, p < 0.001) compared to the VA; whereas the RunScribe™ system underestimated CT (2.3%, p = 0.009). No significant differences were observed in SF and SL between the wearable devices and VA. The intra class correlation coefficient (ICC) revealed an almost perfect association between both systems and high-speed VA (ICC > 0.81). The Bland-Altman plots revealed heteroscedasticity of error (r² = 0.166) for the CT from the Stryd™ system, whereas no heteroscedasticity of error (r² < 0.1) was revealed in the rest of parameters. In conclusion, the results obtained suggest that both foot pods are valid tools for measuring spatiotemporal parameters during running on a treadmill at comfortable velocity. If the limits of agreement of both systems are considered in respect to high-speed VA, the RunScribe™ seems to be a more accurate system for measuring temporal parameters and SL than the Stryd™ system.

The stability of step rate throughout a 3200 meter run

Step rate has been studied in controlled laboratory settings due to its association with biomechanical parameters related to running injuries. However, the stability of step rate in a run over ground when speed is not controlled remains unclear. In this observational cohort study, 30 subjects were asked to run 3200 meters (m) over ground at their self-selected pace during an Army Physical Fitness Test. Stationary cameras were placed along the paved course to capture step rate at 800 m, 1200 m, 1800 m, and 2200 m. For analysis of step rate at four different time points, a repeated measures analysis of variance (ANOVA) with a Bonferroni-Holm correction was utilized to determine statistical difference with a significance level set at p < 0.05 (95% confidence intervals). There was a statistically significant (p = 0.04) difference between step rate at two different time points; however, the mean group difference in step rate was approximately 1-2 steps per minute, which is not likely clinically meaningful. There was no difference in average weekly miles trained or performance time in those who demonstrated a change in step rate versus those who maintained a steady step rate. Clinicians and researchers may be able to expect step rate to be consistent from 800 m-2200 m during a 3200 m timed run regardless of the runner's training mileage or performance time. This may be valuable for observing over ground running characteristics when the full course of a run cannot be viewed as it could within a laboratory setting.

Overuse injuries in runners of different abilities-a one-year prospective study

The aim of this prospective study was to investigate differences in participant characteristics, previous injury, running dynamics during a long-distance run, and training between injured and uninjured runners in runners of different abilities. Center-of-mass acceleration data were collected during a long-distance overground run. Runners were then divided into four groups (elite, advanced, intermediate and slow) based on their finishing time. Participants completed training diaries and were monitored for 1 year. Seventy-six runners completed the prospective study with 39 (51.3%) sustaining a running injury (44% elite, 42% advanced, 54% intermediate, 59% slow). Differences between injured and uninjured runners within each group related to injury included: (1) elite injured runners ran with longer contact times and (2) more slow injured runners reported an injury in previous year, were heavier, had higher body mass and body mass index, ran with lower step frequencies, and ran a greater weekly distance. Advanced injured runners exhibited fatigue changes in step regularity and peak braking during the run that may be related to injury. These findings suggest that runners of different abilities may have different factors related to injury however due to the small sample sizes in the groups this needs to be explored further.

Youth Distance Running: Strategies for Training and Injury Reduction

Running is a popular sport for children in the United States. However, review of available literature on health effects and safety recommendations for youth running has not been previously conducted. Unique factors for injury include periods of growth during puberty and potential for growth plate injury. Youth runners may benefit from activities that incorporate high-impact loading and multidirectional movement for optimal bone maturation, exercises to strengthen tendons and muscles, and strategies aimed at improving running biomechanics to reduce risk of injury. In addition, addressing lifestyle factors, including nutrition and sleep is essential for a runner's general health. Similar to other sports, sports specialization should not be encouraged in youth runners. Reducing running-related injury in growing children and assessing readiness for running should be based on a combination of physical, emotional, psychological, social, and cognitive factors. Youth runners require individualized training and competition to safely participate in the sport.

Is Cadence Related to Leg Length and Load Rate?

BACKGROUND

Increasing cadence is often recommended to reduce load rate and to lower injury risk. However, habitual cadence was recently shown to be unrelated to load rate. Cadence is likely influenced by leg length. If so, then cadence may be related to load rate when it is normalized to leg length.

OBJECTIVES

To examine the relationship between cadence and leg length in both injured and uninjured runners with a rearfoot strike pattern. We hypothesized that increased leg length would be associated with lower cadence. We also evaluated the relationship between cadence normalized to leg length and the vertical average load rate (VALR), expecting that as cadence normalized to leg length increased, VALR would decrease.

METHODS

In this cross-sectional cohort, laboratory-based study, 40 uninjured and 42 injured recreational runners with a rearfoot strike pattern were measured at self-selected speeds. The relationship of cadence to leg length was measured between groups by injury status. A secondary analysis evaluated the relationship between cadence normalized to leg length and VALR. The data were analyzed using a multiple linear regression, with injury status as a covariate. Alpha was set to .05.

RESULTS

Accounting for injury status, leg length had a moderate negative association with cadence (P<.001, r = 0.449, standardized β = - 0.443). There were no associations of VALR with cadence normalized to leg length by injury status or across participants.

CONCLUSION

Lower cadence was observed in recreational runners with longer legs, regardless of injury status. However, cadence was not related to load rate when normalized to leg length. J Orthop Sports Phys Ther 2019;49(4):280-283. doi:10.2519/jospt.2019.8420.

Mobile Technology in Running Science and Medicine: Are We Ready?

Since the running revolution of the 1970s, one of the major challenges has been the burden of running-related injuries (RRIs). Researchers, sports medicine practitioners, and strength and conditioning coaches are striving to develop an understanding of which factors may increase an individuals risk of developing RRIs, which strategies can be used to ensure optimal rehabilitation and recovery from an injury, and how to best optimize athletic performance. This Viewpoint explores these factors to demonstrate how recent advances in mobile technology may allow us to uncover novel insights related to the science and medicine of running. J Orthop Sports Phys Ther 2019;49(3):122-125. doi:10.2519/jospt.2019.0604.

Tibiofemoral Joint Forces in Female Recreational Runners Vary with Step Frequency

PURPOSE

Elevated tibiofemoral joint (TFJ) contact forces have been linked to the development and progression of knee osteoarthritis. The primary objective of this study was to determine the association between peak TFJ shear and compression forces during running at different self-selected step frequencies (SF) in female recreational runners.

METHODS

Fifty-five healthy female recreational runners ran at 2.98 m·s on an instrumented treadmill. Peak TFJ anterior shear force, peak axial TFJ compression force, and peak medial compartment TFJ compression force were estimated using a musculoskeletal model with inputs from 3D joint kinematics and inverse dynamics calculations. Three SF groups were generated using tertiles, and differences between the groups were compared using one-way ANOVA (α = 0.05).

RESULTS

Runners with an SF of ≥178 steps per minute demonstrated the lowest peak TFJ anterior shear force (P = 0.04), peak axial TFJ compression force (P = 0.01), and peak TFJ medial compartment compression forces (P = 0.01) compared with runners using lower SF.

CONCLUSION

Female recreational runners with low SF of ≤166 steps per minute experience greater TFJ contact forces. This study provides evidence of an association between SF and both shear and axial peak TFJ contact forces during running.

Risk factors for patellofemoral pain: a systematic review and meta-analysis

BACKGROUND

Patellofemoral pain (PFP) is a prevalent condition commencing at various points throughout life. We aimed to provide an evidence synthesis concerning predictive variables for PFP, to aid development of preventative interventions.

METHODS

We searched Medline, Web of Science and SCOPUS until February 2017 for prospective studies investigating at least one potential risk factor for future PFP. Two independent reviewers appraised methodological quality using the Newcastle-Ottawa Scale. We conducted meta-analysis where appropriate, with standardised mean differences (SMD) and risk ratios calculated for continuous and nominal scaled data.

RESULTS

This review included 18 studies involving 4818 participants, of whom 483 developed PFP (heterogeneous incidence 10%). Three distinct subgroups (military recruits, adolescents and recreational runners) were identified. Strong to moderate evidence indicated that age, height, weight, body mass index (BMI), body fat and Q angle were not risk factors for future PFP. Moderate evidence indicated that quadriceps weakness was a risk factor for future PFP in the military, especially when normalised by BMI (SMD -0.69, CI -1.02, -0.35). Moderate evidence indicated that hip weakness was not a risk factor for future PFP (multiple pooled SMDs, range -0.09 to -0.20), but in adolescents, moderate evidence indicated that increased hip abduction strength was a risk factor for future PFP (SMD 0.71, CI 0.39, 1.04).

CONCLUSIONS

This review identified multiple variables that did not predict future PFP, but quadriceps weakness in military recruits and higher hip strength in adolescents were risk factors for PFP. Identifying modifiable risk factors is an urgent priority to improve prevention and treatment outcomes.

Running mechanics of females with bilateral compartment syndrome

[Purpose] Primary purpose was to compare running mechanics between healthy runners and runners with chronic exertional compartment syndrome (CECS) including overstride angles, ankle dorsiflexion (DF) angles, and foot strike patterns. The secondary purpose was to analyze the association between the overstride angles and ankle DF angles. [Participants and Methods] Running images of 7 female runners with bilateral CECS patients were captured at a time of the medical examination. Their running images were compared with gender, age, and body mass index matched 31 healthy control runners. [Results] The bilateral CECS female runners have a propensity of running with significantly greater overstride and ankle DF angles than the healthy female runners. There were no foot strike differences between the two cohorts. There were a non-significant, poor relationship between overstride and ankle DF angles in the healthy female runners while a significant, strong association was found between overstride and ankle DF angles in the bilateral CECS female runners. [Conclusion] Compared to healthy female runners, bilateral CECS female runners demonstrated different running mechanics including greater overstride and ankle DF angles. The two variables were strongly associated with each other in bilateral CECS female runners, but not in healthy female runners. This may potentially contribute to the mechanism of CECS development.

Acute changes in foot strike pattern and cadence affect running parameters associated with tibial stress fractures

Tibial stress fractures are a common and debilitating injury that occur in distance runners. Runners may be able to decrease tibial stress fracture risk by adopting a running pattern that reduces biomechanical parameters associated with a history of tibial stress fracture. The purpose of this study was to test the hypothesis that converting to a forefoot striking pattern or increasing cadence without focusing on changing foot strike type would reduce injury risk parameters in recreational runners. Running kinematics, ground reaction forces and tibial accelerations were recorded from seventeen healthy, habitual rearfoot striking runners while running in their natural running pattern and after two acute retraining conditions: (1) converting to forefoot striking without focusing on cadence and (2) increasing cadence without focusing on foot strike. We found that converting to forefoot striking decreased two risk factors for tibial stress fracture: average and peak loading rates. Increasing cadence decreased one risk factor: peak hip adduction angle. Our results demonstrate that acute adaptation to forefoot striking reduces different injury risk parameters than acute adaptation to increased cadence and suggest that both modifications may reduce the risk of tibial stress fractures.

The use of wearable devices for walking and running gait analysis outside of the lab: A systematic review

BACKGROUND

Quantitative gait analysis is essential for evaluating walking and running patterns for markers of pathology, injury, or other gait characteristics. It is expected that the portability, affordability, and applicability of wearable devices to many different populations will have contributed advancements in understanding the real-world gait patterns of walkers and runners. Therefore, the purpose of this systematic review was to identify how wearable devices are being used for gait analysis in out-of-lab settings.

METHODS

A systematic search was conducted in the following scientific databases: PubMed, Medline, CINAHL, EMBASE, and SportDiscus. Each of the included articles was assessed using a custom quality assessment. Information was extracted from each included article regarding the participants, protocol, sensor(s), and analysis.

RESULTS

A total of 61 articles were reviewed: 47 involved gait analysis during walking, 13 involved gait analysis during running, and one involved both walking and running. Most studies performed adequately on measures of reporting, and external and internal validity, but did not provide a sufficient description of power. Small, unobtrusive wearable devices have been used in retrospective studies, producing unique measures of gait quality. Walking, but not running, studies have begun to use wearable devices for gait analysis among large numbers of participants in their natural environment.

CONCLUSIONS

Despite the advantages provided by the portability and accessibility of wearable devices, more studies monitoring gait over long periods of time, among large numbers of participants, and in natural walking and running environments are needed to analyze real-world gait patterns, and would facilitate prospective, subject-specific, and subgroup investigations. The development of wearables-specific metrics for gait analysis provide insights regarding the quality of gait that cannot be determined using traditional components of in-lab gait analyses. However, guidelines for the usability of wearable devices and the validity of wearables-based measurements of gait quality need to be established.

Shoe cushioning, body mass and running biomechanics as risk factors for running injury: a study protocol for a randomised controlled trial

INTRODUCTION

Repetitive loading of the musculoskeletal system is suggested to be involved in the underlying mechanism of the majority of running-related injuries (RRIs). Accordingly, heavier runners are assumed to be at a higher risk of RRI. The cushioning system of modern running shoes is expected to protect runners again high impact forces, and therefore, RRI. However, the role of shoe cushioning in injury prevention remains unclear. The main aim of this study is to investigate the influence of shoe cushioning and body mass on RRI risk, while exploring simultaneously the association between running technique and RRI risk.

METHODS AND ANALYSIS

This double-blinded randomised controlled trial will involve about 800 healthy leisure-time runners. They will randomly receive one of two running shoe models that will differ in their cushioning properties (ie, stiffness) by ~35%. The participants will perform a running test on an instrumented treadmill at their preferred running speed at baseline. Then they will be followed up prospectively over a 6-month period, during which they will self-report all their sports activities as well as any injury in an internet-based database TIPPS (Training and Injury Prevention Platform for Sports). Cox regression analyses will be used to compare injury risk between the study groups and to investigate the association among training, biomechanical and anatomical risk factors, and injury risk.

ETHICS AND DISSEMINATION

The study was approved by the National Ethics Committee for Research (Ref: 201701/02 v1.1). Outcomes will be disseminated through publications in peer-reviewed journals, presentations at international conferences, as well as articles in popular magazines and on specialised websites.

TRIAL REGISTRATION NUMBER

NCT03115437, Pre-results.

Manipulation of Foot Strike and Footwear Increases Achilles Tendon Loading During Running

BACKGROUND

The Achilles tendon is the most common site of tendon overuse injury in humans. Running with a forefoot strike pattern and in minimal shoes is a topic of recent interest, yet evidence is currently limited regarding the combined influence of foot strike and footwear on Achilles tendon loading.

PURPOSE

To investigate the influence of both foot strike and footwear on Achilles tendon loading in habitual rearfoot strike runners.

STUDY DESIGN

Controlled laboratory study.

METHODS

Synchronized kinematic and force data were collected from 22 habitual rearfoot strikers (11 male), who habitually ran in nonminimal running shoes, during overground running at 3.6 m·s^-1. Participants ran in 3 different footwear conditions (standard running shoe, minimal running shoe, and barefoot) with both a rearfoot strike (RFS) and an imposed forefoot strike (FFS) in each footwear condition. Achilles tendon loading was estimated by use of inverse dynamics, where the Achilles tendon moment arm was determined with a regression equation. A 2-way, repeated-measures analysis of variance was used to compare conditions.

RESULTS

Achilles tendon impulse was greater when subjects ran with an FFS rather than an RFS in minimal shoes. Achilles tendon loading rates were higher when subjects ran either in minimal shoes or barefoot than in standard shoes, regardless of foot strike.

CONCLUSION

In runners who habitually rearfoot strike in standard running shoes, running in minimal shoes or barefoot increased the rate of tendon loading, and running with a forefoot strike in minimal shoes increased the magnitude of tendon loading.

CLINICAL RELEVANCE

Transitioning to these running conditions may increase the risk of tendinopathy.