Background Abnormal hip mechanics are often implicated in female runners with patellofemoral pain. We sought to evaluate a simple gait retraining technique, using a full-length mirror, in female runners with patellofemoral pain and abnormal hip mechanics. Transfer of the new motor skill to the untrained tasks of single leg squat and step descent was also evaluated. Methods Ten female runners with patellofemoral pain completed 8 sessions of mirror and verbal feedback on their lower extremity alignment during treadmill running. During the last 4 sessions, mirror and verbal feedback were progressively removed. Hip mechanics were assessed during running gait, a single leg squat and a step descent, both pre- and post-retraining. Subjects returned to their normal running routines and analyses were repeated at 1-month and 3-month post-retraining. Data were analyzed via repeated measures analysis of variance. Findings Subjects reduced peaks of hip adduction, contralateral pelvic drop, and hip abduction moment during running (P<0.05, effect size=0.69–2.91). Skill transfer to single leg squatting and step descent was noted (P<0.05, effect size=0.91–1.35). At 1 and 3 months post retraining, most mechanics were maintained in the absence of continued feedback. Subjects reported improvements in pain and function (P<0.05, effect size=3.81–7.61) and maintained through 3 months post retraining. Interpretation Mirror gait retraining was effective in improving mechanics and measures of pain and function. Skill transfer to the untrained tasks of squatting and step descent indicated that a higher level of motor learning had occurred. Extended follow-up is needed to determine the long term efficacy of this treatment.

B Clinicians should administer appropriate clinical or field tests that reproduce pain and assess lower-limb movement coordination, such as squatting, step-downs, and single-leg squats. These tests can assess a patient's baseline status relative to pain, function, and disability; global knee function; and changes in status throughout the course of treatment. EXAMINATION -ACTIVITY LIMITATIONS/ PHYSICAL IMPAIRMENT MEASURESC When evaluating a patient with PFP over an episode of care, clinicians may assess body structure and function, including measures of patellar provocation, patellar mobility, foot position, hip and thigh muscle strength, and muscle length.

We sought to determine if an in-field gait retraining program can reduce excessive impact forces and peak hip adduction without adverse changes in knee joint work during running. Thirty healthy at-risk runners who exhibited high-impact forces were randomized to retraining [21.1 (± 1.9) years, 22.1 (± 10.8) km/week] or control groups [21.0 (± 1.3) years, 23.2 (± 8.7) km/week]. Retrainers were cued, via a wireless accelerometer, to increase preferred step rate by 7.5% during eight training sessions performed in-field. Adherence with the prescribed step rate was assessed via mobile monitoring. Three-dimensional gait analysis was performed at baseline, after retraining, and at 1-month post-retraining. Retrainers increased step rate by 8.6% (P < 0.0001), reducing instantaneous vertical load rate (-17.9%, P = 0.003), average vertical load rate (-18.9%, P < 0.0001), peak hip adduction (2.9° ± 4.2 reduction, P = 0.005), eccentric knee joint work per stance phase (-26.9%, P < 0.0001), and per kilometer of running (-21.1%, P < 0.0001). Alterations in gait were maintained at 30 days. In the absence of any feedback, controls maintained their baseline gait parameters. The majority of retrainers were adherent with the prescribed step rate during in-field runs. Thus, in-field gait retraining, cueing a modest increase in step rate, was effective at reducing impact forces, peak hip adduction and eccentric knee joint work.

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Background Treadmills are often used in research, clinical practice, and training. Biomechanical investigations comparing treadmill and overground running report inconsistent findings. Objective This study aimed at comparing biomechanical outcomes between motorized treadmill and overground running. Methods Four databases were searched until June 2019. Crossover design studies comparing lower limb biomechanics during non-inclined, non-cushioned, quasi-constant-velocity motorized treadmill running with overground running in healthy humans (18-65 years) and written in English were included. Meta-analyses and meta-regressions were performed where possible. Results 33 studies (n = 494 participants) were included. Most outcomes did not differ between running conditions. However, during treadmill running, sagittal foot-ground angle at footstrike (mean difference (MD) − 9.8° [95% confidence interval: − 13.1 to − 6.6]; low GRADE evidence), knee flexion range of motion from footstrike to peak during stance (MD 6.3° [4.5 to 8.2]; low), vertical displacement center of mass/pelvis (MD − 1.5 cm [− 2.7 to − 0.8]; low), and peak propulsive force (MD − 0.04 body weights [− 0.06 to − 0.02]; very low) were lower, while contact time (MD 5.0 ms [0.5 to 9.5]; low), knee flexion at footstrike (MD − 2.3° [− 3.6 to − 1.1]; low), and ankle sagittal plane internal joint moment (MD − 0.4 Nm/kg [− 0.7 to − 0.2]; low) were longer/higher, when pooled across overground surfaces. Conflicting findings were reported for amplitude of muscle activity. Conclusions Spatiotemporal, kinematic, kinetic, muscle activity, and muscle-tendon outcome measures are largely comparable between motorized treadmill and overground running. Considerations should, however, particularly be given to sagittal plane kinematic differences at footstrike when extrapolating treadmill running biomechanics to overground running. Protocol registration CRD42018083906 (PROSPERO International Prospective Register of Systematic Reviews).

Height obtained during the single-leg standing heel-rise test performed 1 year after ATR related to the long-term ability to regain normal ankle biomechanics. Minimizing tendon elongation and regaining heel-rise height may be important for the long-term recovery of ankle biomechanics, particularly during more demanding activities such as jumping.

These data suggest that after an Achilles tendon rupture, patients may be susceptible to greater mechanical loading of the knee during sporting tasks, regardless of surgical or nonsurgical treatment.

We evaluated the efficacy of an in-field gait retraining programme using mobile biofeedback to reduce cumulative and peak tibiofemoral loads during running. Thirty runners were randomised to either a retraining group or control group. Retrainers were asked to increase their step rate by 7.5% over preferred in response to real-time feedback provided by a wrist mounted running computer for 8 routine in-field runs. An inverse dynamics driven musculoskeletal model estimated total and medial tibiofemoral joint compartment contact forces. Peak and impulse per step total tibiofemoral contact forces were immediately reduced by 7.6% and 10.6%, respectively (P < 0.001). Similarly, medial tibiofemoral compartment peak and impulse per step tibiofemoral contact forces were reduced by 8.2% and 10.6%, respectively (P < 0.001). Interestingly, no changes were found in knee adduction moment measures. Post gait retraining, reductions in medial tibiofemoral compartment peak and impulse per step tibiofemoral contact force were still present (P < 0.01). At the 1-month post-retraining follow-up, these reductions remained (P < 0.05). With these per stance reductions in tibiofemoral contact forces in mind, cumulative tibiofemoral contact forces did not change due to the estimated increase in number of steps to run 1 km.