Persistence Of Altered Kinematics Following A Typical Training Run At 24hrs

Abstract

Running participation has increased since the 1970’s, concomitant with the rise in popularity has been the rise in running related injuries. Epidemiological studies have reported 2.5 to 33.0 injuries for every 1000 hours of running, with most common injuries being overuse knee injuries. There is a common consensus that altered hip and knee kinematics are risk factors for developing overuse injuries. Previously we demonstrated altered gait kinematics as result of fatigue following a high intensity interval training run (HIIT). These fatigue induced alterations in kinematics could place runners at greater risk of developing an overuse injury. To date, the time course of recovery for gait kinematics is unknown. If these gait changes remain at the onset of the next training run this could be a precursor to overuse injury. PURPOSE: To examine the time course of kinematic changes immediately after and 24hr post HIIT. METHODS: Twenty (10F, 10M) healthy recreational runners performed a HIIT session consisting of six repetitions of 800 meters, each run at 1km.h-1 under the speed at VO2 max, with a 1:1 work: rest ratio. Kinematics were examined during a 6-minute, medium intensity run, performed at halfway between the speeds at lactate threshold and lactate turnpoint. The 6-min run was performed pre, post, and 24hr post HIIT. Maximum angle and range of motion (RoM) of the hip and knee during ground contact were analysed in sagittal and frontal planes. One way repeated measures ANOVA was performed to assess changes over time. RESULTS: Hip frontal angles were significantly increased with time for both maximum angles (P < 0.001) and RoM (P = 0.001). Post hoc analysis revealed a significant increase in maximum hip adduction angle immediately post (P < 0.001, d = 0.91) and at 24hr post (P < 0.001, d = 0.86) compared to pre. Hip frontal RoM was also increased significantly at post (P < 0.001, d = 0.85) and at 24hr (P < 0.001, d = 0.74). Knee kinematics were affected by time for maximum angle of knee frontal plane (P = 0.046) and sagittal plane knee RoM (P = 0.015). However, there was no presence of altered knee kinematics at 24hr. CONCLUSION: The HIIT session induced kinematic alterations to the hip frontal angles. In some runners these alterations were still present 24 hours after HIIT. For these runners, this could increase the risk of developing overuse injuries.