Sensor location influences the associations between IMU and motion capture measurements of impact landing in healthy male and female runners at multiple running speeds.

This study investigated the relationships between inertial measurement unit (IMU) acceleration at multiple body locations and 3D motion capture impact landing measures in runners. Thirty healthy runners ran on an instrumented treadmill at five running speeds (9-17 km/h) during 3D motion capture. Axial and resultant acceleration were collected from IMUs at the distal and proximal tibia, distal femur and sacrum. Relationships between peak acceleration from each IMU location and patellofemoral joint (PFJ) peak force and loading rate, impact peak and instantaneous vertical loading rate (IVLR) were investigated using linear mixed models. Acceleration was positively related to IVLR at all lower limb locations (p < 0.01). Models predicted a 1.9-3.2 g peak acceleration change at the tibia and distal femur, corresponding with a 10% IVLR change. Impact peak was positively related to acceleration at the distal femur only (p < 0.01). PFJ peak force was positively related to acceleration at the distal (p = 0.03) and proximal tibia (p = 0.03). PFJ loading rate was positively related to the tibia and femur acceleration in males only (p < 0.01). These findings suggest multiple IMU lower limb locations are viable for measuring peak acceleration during running as a meaningful indicator of IVLR.

Optimizing Wearable Device and Testing Parameters to Monitor Running-Stride Long-Range Correlations for Fatigue Management in Field Settings.

PURPOSE: There are important methodological considerations for translating wearable-based gait-monitoring data to field settings. This study investigated different devices' sampling rates, signal lengths, and testing frequencies for athlete monitoring using dynamical systems variables. METHODS: Secondary analysis of previous wearables data (N = 10 runners) from a 5-week intensive training intervention investigated impacts of sampling rate (100-2000 Hz) and signal length (100-300 strides) on detection of gait changes caused by intensive training. Primary analysis of data from 13 separate runners during 1 week of field-based testing determined day-to-day stability of outcomes using single-session data and mean data from 2 sessions. Stride-interval long-range correlation coefficient α from detrended fluctuation analysis was the gait outcome variable. RESULTS: Stride-interval α reduced at 100- and 200- versus 300- to 2000-Hz sampling rates (mean difference: -.02 to -.08; P ≤ .045) and at 100- compared to 200- to 300-stride signal lengths (mean difference: -.05 to -.07; P < .010). Effects of intensive training were detected at 100, 200, and 400 to 2000 Hz (P ≤ .043) but not 300 Hz (P = .069). Within-athlete α variability was lower using 2-session mean versus single-session data (smallest detectable change: .13 and .22, respectively). CONCLUSIONS: Detecting altered gait following intensive training was possible using 200 to 300 strides and a 100-Hz sampling rate, although 100 and 200 Hz underestimated α compared to higher rates. Using 2-session mean data lowers smallest detectable change values by nearly half compared to single-session data. Coaches, runners, and researchers can use these findings to integrate wearable-device gait monitoring into practice using dynamic systems variables.

Cumulative patellofemoral force and stress are lower during faster running compared to slower running in recreational runners.

Management strategies for patellofemoral pain often involve modifying running distance or speed. However, the optimal modification strategy to manage patellofemoral joint (PFJ) force and stress accumulated during running warrants further investigation. This study investigated the effect of running speed on peak and cumulative PFJ force and stress in recreational runners. Twenty recreational runners ran on an instrumented treadmill at four speeds (2.5-4.2 m/s). A musculoskeletal model derived peak and cumulative (per 1 km of continuous running) PFJ force and stress for each speed. Cumulative PFJ force and stress decreased with faster speeds (9.3-33.6% reduction for 3.1-4.2 m/s vs. 2.5 m/s). Peak PFJ force and stress significantly increased with faster speeds (9.3-35.6% increase for 3.1-4.2 m/s vs. 2.5 m/s). The largest cumulative PFJ kinetics reductions occurred when speeds increased from 2.5 to 3.1 m/s (13.7-14.2%). Running at faster speeds increases the magnitude of peak PFJ kinetics but conversely results in less accumulated force over a set distance. Selecting moderate running speeds (~3.1 m/s) with reduced training duration or an interval-based approach may be more effective for managing cumulative PFJ kinetics compared to running at slow speeds.

The Effectiveness of Gait Retraining on Running Kinematics, Kinetics, Performance, Pain, and Injury in Distance Runners: A Systematic Review With Meta-analysis.

OBJECTIVE: To evaluate the effectiveness of running gait retraining on kinematics, kinetics, performance, pain, and injury in distance runners. DESIGN: Intervention systematic review with meta-analysis. LITERATURE SEARCH: Seven electronic databases from inception to March 2021. TRIAL SELECTION CRITERIA: Randomized controlled trials that (1) evaluated running gait retraining compared to no intervention, usual training, placebo, or standard care and (2) reported biomechanical, physiological, performance, or clinical outcomes. DATA SYNTHESIS: Random-effects metaanalyses were completed, and the certainty of evidence was judged using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. We categorized interventions into step rate, non-rearfoot footstrike, impact, ground contact time, and multiparameter subgroups. RESULTS: We included 19 trials (673 participants). Moderate-certainty evidence indicated step rate gait retraining increased step rate (SMD 1.03 [95% confidence interval {CI}: 0.63, 1.44]; number of trials (N): 4; I2: 0%) and reduced average vertical loading rate (SMD -0.57 [95% CI, -1.05 to -0.09], N: 3; I2: 0%). Low-certainty evidence indicated non-rearfoot footstrike retraining increased knee flexion at initial contact (SMD 0.74 [95% CI, 0.11 to 1.37]; N: 2; I2: 0%), but did not alter running economy (SMD 0.21 [95% CI, -1.11 to 1.52]; N: 3; I2: 19%).). Low-certainty evidence indicated multiparameter retraining did not alter running economy (SMD 0.32 [-0.39, 1.02]; N: 3; I2: 19%) or performance (SMD 0.14 [95% CI, -4.87 to 4.58]; N: 2; I2: 18%). Insufficient trials reported on pain outcomes. Two trials demonstrated reduced 1-year injury incidence following gait retraining. CONCLUSIONS: Gait retraining interventions altered step rate and knee kinematics, lowered vertical loading rates, and did not affect running performance. J Orthop Sports Phys Ther 2022;52(4):192-206. Epub 05 Feb 2022. doi:10.2519/jospt.2022.10585.

Adoption and use of guidelines for whiplash: an audit of insurer and health professional practice in New South Wales, Australia.

BACKGROUND: In Australia, the New South Wales (NSW) State Insurance Regulatory Authority has been continuously developing and implementing clinical practice guidelines to address the health and economic burden from whiplash associated disorders (WAD). Despite this, it is uncertain the extent to which the guidelines are followed. This study aimed to determine insurer and health professional compliance with recommendations of the 2014 NSW clinical practice guidelines for the management of acute WAD; and explore factors related to adherence. METHODS: This was an observational study involving an audit of 288 randomly-selected claimant files from 4 insurance providers in NSW, Australia between March and October 2016. Data extracted included demographic, claim and injury details, use of health services, and insurer and health professional practices related to the guidelines. Analyses involved descriptive statistics and correlation analysis. RESULTS: Median time for general practitioner medical consultation was 4 days post-injury and 25 days for physical treatment (e.g. physiotherapy). Rates of x-ray investigations were low (21.5%) and most patients (90%) were given active treatments in line with the guideline recommendations. The frequency of other practices recommended by the guidelines suggested lower guideline adherence in some areas such as; using the Quebec Task Force classification (19.9%); not using specialised imaging for WAD grades I and II (e.g. MRI, 45.8%); not using routine passive treatments (e.g. manual therapy, 94.0%); and assessing risk of non-recovery using relevant prognostic tools (e.g. Neck Disability Index, 12.8%). Over half of the claimants (59.0%) were referred to other professionals at 9-12 weeks post-injury, among which 31.2% were to psychologists and 68.8% to specialists (surgical specialists, 43.6%; WAD specialists, 20.5%). Legal representation and lodgment of full claim were associated with increased number of medical visits and imaging (ρ 0.23 to 0.3; p < 0.01). CONCLUSION: There is evidence of positive uptake of some guideline recommendations by insurers and health professionals; however, there are practices that are not compliant and might lead to poor health outcomes and greater treatment cost. Organisational, regulatory and professional implementation strategies may be considered to change practice, improve scheme performance and ultimately improve outcomes for people with WAD.