Biomechanical And Perceived Effort Responses Of Adolescent Runners To Cadence Manipulation In A Natural Environment

PURPOSE: For adults, increasing cadence above a preferred step rate reduces peak joint angles and forces. Most cadence manipulation studies have been conducted in adults and in laboratory settings. The potential influence of development that occurs during maturation and running in a controlled lab setting questions the ecological validity of generalizing results from adults to adolescent runners. We investigated if increasing cadence above an adolescent runner’s preferred cadence alters peak joint angles, impact accelerations and perceived effort. METHODS: Adolescent runners (F = 16, M = 12, age = 16 ± 1 y) completed three, 1.6 km running sessions on a paved path at 80% of their self-reported 5 km race pace while monitored with a GPS watch (average speed = 3.28 ± 0.51 m/s). Participants ran at their preferred cadence (baseline) and then when matching their steps to a metronome programmed at +5% and + 10% of their preferred cadence. We measured joint angles and resultant tibial acceleration with IMUs secured to shanks, thighs, and sacrum. Participants reported perceived effort based on rating of perceived exertion and NASA Task Load Index components after each condition. We performed paired t tests (p ≤ .05) to compare peak joint angles, tibial acceleration, and perceived effort among conditions. Analyses only included participants who increased cadence by 2.5-7.5% or 7.5-12.5% for the +5% (n = 22) or + 10% conditions (n = 13), respectively. RESULTS: Perceived effort increased and peak knee flexion decreased when increasing cadence (Table 1). CONCLUSIONS: Most adolescents successfully increased cadence by +5%, but less than half successfully increased cadence by 10%. Due to the greater perceived effort, manipulating cadence in a more controlled setting (e.g., treadmill) with gradual increases in cadence before transitioning to an outdoors environment may improve the long-term successfulness of increasing cadence for adolescents.