Influence of Stride Frequency and Length on Running Mechanics: A Systematic Review

CONTEXT: A high number of recreational runners sustain a running-related injury each year. To reduce injury risk, alterations in running form have been suggested. One simple strategy for running stride frequency or length has been commonly advocated. OBJECTIVE: To characterize how running mechanics change when stride frequency and length are manipulated. DATA SOURCES: In January 2012, a comprehensive search of PubMed, CINAHL Plus, SPORTDiscus, PEDro, and Cochrane was performed independently by 2 reviewers. A second search of the databases was repeated in June 2012 to ensure that no additional studies met the criteria after the initial search. STUDY SELECTION: Inclusion criteria for studies were an independent variable including manipulation of stride frequency or length at a constant speed with outcome measures of running kinematics or kinetics. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 3. DATA EXTRACTION: Two reviewers independently appraised each article using a modified version of the Quality Index, designed for assessing bias of nonrandomized studies. RESULTS: Ten studies met the criteria for this review. There was consistent evidence that increased stride rate resulted in decreased center of mass vertical excursion, ground reaction force, shock attenuation, and energy absorbed at the hip, knee, and ankle joints. All but 1 study had a limited number of participants, with several methodological differences existing among studies (eg, overground and treadmill running, duration of test conditions). Although speed was held constant during testing, it was individually self-selected or fixed. Most studies used only male participants. CONCLUSION: Despite procedural differences among studies, an increased stride rate (reduced stride length) appears to reduce the magnitude of several key biomechanical factors associated with running injuries.