Lower limb tri-joint synchrony during running gait: A longitudinal age-based study

Biomechanical research exploring the age-based mechanics of running gait can provide valuable insight into the reported decline in master endurance running performance. However, few studies have shown consistent biomechanical differences in the gait of trained distance runners compared to their younger counterparts. It might be that differences occur in the interaction between joints. The aim was to explore the differences in in tri-joint synchrony of the lower limb, quantified through Cluster Phase analysis, of runners at 50 years of age compared to seven years later. Cluster Phase analysis was used to examine changes in synchrony between 3 joints of the lower limb during the stance phase of running. Ten male, endurance-trained athletes M50 (age = 53.54±2.56 years, mass = 71.05±7.92 kg) participated in the study and returned after seven years M57 (age = 60.49±2.56 years, mass = 69.08±8.23 kg). Lower limb kinematics (Vicon, 120 Hz) and ground reaction forces (Kistler, 1080 Hz) were collected as participants performed multiple trials at a horizontal running velocity = 3.83±0.40 m·s-1 over the force plate. Significant increase (31 %) in rate of force development in the absorption phase, and significantly reduced sagittal plane knee joint range of motion (30.50 v 23.68o) were found following the seven years of ageing. No further discrete single joint measures were significantly different between M50 and M57. Joint synchrony between the hip, knee and ankle was significantly higher at M57 compared to M50 during the absorption phase of stance. The force attenuation strategy is compromised after seven years of ageing, which is associated with more synchronous movements in the lower limb joints. Increased joint synchrony as a function of age could be a mechanism associated with this key injury provoking phase of running gait.