The effect of a cadence retraining protocol on lower limb sagittal plane kinematics and EMG activity in a normal population of social runners

Background: Altering running cadence is a popular method for reducing the occurrence of running related injuries. Increasing running cadence has been shown to increase activation of hip musculature and reduce hip adduction and internal rotation. This has identified increasing cadence as an effective method of treating patella-femoral pain syndrome (PFPS). However, little is known about the long term effects to sagittal plane kinematics of the knee and ankle, or differences in tibialis anterior (TA) and medial gastrocnemius (MG) activation during running. Changes to plantarflexion range of motion and heel positioning at initial contact, and the subsequent effect on TA and MG activation, are risk factors for running related injuries such as medial tibial stress syndrome (MTSS) and chronic exertional compartment syndrome (CECS). This study looked to characterise the effect of three week cadence retraining protocol on ankle and knee sagittal plane kinematics and on TA and MG electromyography (EMG) activity.

Methods: 16 runners participated in the study. Subjects were measured for base line parameters and trained to increase their preferred running cadence (PC) by 10%. Kinematic and EMG data were collected for PC, post initial training (PIT) and post three weeks training (PT). PC was remeasured after six weeks.

Results: No significant changes occurred in sagittal plane kinematics or MG function. TA activity decreased during loading response (LR) and pre activation (PA) between PIT and PT. However there was no change in TA from PC to PT and no subsequent alteration in ankle plantarflexion at initial contact. Average cadence was increased by 9 ± 4.5% after a six week period.

Discussion: The results of the study imply a cadence training protocol had no effect on sagittal plane kinematics of the knee and ankle, or on activation patterns of TA and MG, following a three week intervention. This suggests that training cadence alone may not be a viable treatment method for MTSS or CECS. However there was statistically significant decrease in TA activation initially during LR and PA between PIR and PT. There was also a non-statistically significant decrease in TA activation of 20% during LR from PC and PT, and 10% during PA from PC to PT; whilst this is not statistically significant it does suggest that further research with a longer sustained retraining program is required to develop a proper understanding of retraining running cadence on the examined mechanics.