# Effectiveness of Lower-Cost Strategies for Running Gait Retraining: A Systematic Review
###### Abstract  
The effectiveness of lower-cost equipment used for running gait retraining is still unclear. The objective of this systematic review was to evaluate the effectiveness of lower-cost equipment used in running gait retraining in altering biomechanical outcomes that may be associated with injuries. The literature search included all documents from MEDLINE, Web of Science, CINAHL, SPORTDiscus, and Scopus. The studies were assessed for risk of bias using an evaluation tool for cross-sectional studies. After screening 2167 initial articles, full-text screening was performed in 42 studies, and 22 were included in the systematic review. Strong evidence suggested that metronomes, smartwatches, and digital cameras are effective in running gait retraining programs as tools for intervention and/or evaluation of results when altering step cadence and foot strike patterns. Strong evidence was found on the effectiveness of accelerometers in interventions with feedback to reduce the peak positive acceleration (PPA) of the lower leg and/or footwear while running. Finally, we found a lack of studies that exclusively used lower-cost equipment to perform the intervention/assessment of running retraining. biomechanics; runners; feedback; cadence; foot strike pattern +
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variables, among others; these studies also reported changes in the variables of kinematics, kinetics, and electromyography [18]. In this sense, several studies have documented the alterations in running mechanics in runners who develop injuries such as excessive pronation of the foot [19; 20], accentuated hip adduction [21], increased internal hip rotation, contralateral pelvic drop, and a reduction in the peak hip flexion, among others [22]. In recent years, studies have proposed changes to running techniques (i.e., movement) through running retraining with feedback in order to reduce impact loads (force applied to the skeleton when contact with the ground occurs) as a way to reduce injury risk [23; 24; 25; 26; 27; 28; 29; 30; 31; 32]. Outcome measures concentrated on determining the effectiveness of running retraining using visual and/or auditory feedback in real time to modify kinematics and kinetics during running [22; 33; 34; 35; 36]. The step rate was shown to significantly reduce impact forces in long-distance runners with an increase of only 5% in step cadence [24]. The study identified that by increasing the step rate, kinematic variables such as the step length, vertical oscillation of the center of mass, and angle of inclination of the foot were reduced. The reductions in these variables were associated with decreased impact forces that could theoretically reduce the risk of injuries. Other authors supported a reduction in impact forces by increasing the cadence or rate of steps [37; 38; 39]. Increasing step cadence with a proportional reduction in the stride length at a constant speed has been shown to facilitate a reduction in foot inclination angles and impact forces. This decreases the number of initial contacts on the ground by the hindfoot during the step [37; 39; 40]. In this sense, some studies analyzed the change in the strike pattern and proposed a shift from stepping on the rearfoot to stepping on the middle or forefoot because the impact forces on the knees and hips are typically higher for heel striking compared to midfoot or forefoot striking [37; 41; 42]. It was reported that approximately 80% of recreational runners who use traditional running shoes opted for heel striking [43; 44]. Thus, changing the strike pattern through gait retraining could be a way to reduce impact forces and the risk of injuries related to running [35; 45; 46; 47; 48]. A systematic review with meta-analyses to assess the effectiveness of running retraining on kinematics, kinetics, performance, pain, and injury in long-distance runners [49] found that gait retraining was effective in increasing the step cadence and reducing the mean vertical load rate.