The Landing Pattern on Ankle Instability

Abstract

PURPOSE: The first aim of this study was to identify the normal landing pattern using detailed biomechanical analysis including analysis of the kinematics and ground reaction force. The second aim of the study is to investigate the landing pattern in the subjects with recurrent ankle sprain and compare this landing pattern with those in normal subjects. METHODS: 23 adults with recurrent lateral ankle sprains were recruited in this study, and 25 healthy male adults who were free from any injury of lower extremity were enrolled as control group. All subjects would be asked to perform level walking and drop landing from platforms with 0.5 m. Subjects would repeat at least 3 times for each condition. Those movements were collected by VICON 512 (Oxford Metrics, UK) motion analysis system and the kinematics was analyzed using BodyBuilder® software. The ground reaction force of both lower limbs was recorded by two AMTI force platforms, and the kinetic data were calculated with inverse dynamics. RESULTS: When drop landing from platforms with different height, the main differences of kinematics were the maximum flexion angles of hip and knee joints in normal landing patterns and the flexion angles increased with the height. When drop landing from platforms with different height, the main differences were the maximum flexion angles of hip and knee joints, as well as the flexion of pelvis, hip abduction, and knee external rotation in the subjects with recurrent ankle sprains. When compare those two groups, the landing pattern in the subjects with recurrent ankle sprain was significant smaller than normal subjects in knee flexion (65.71°±6.43° vs. 70.19°±13.76°) and hip flexion (34.15°±5.42° vs. 42.54°±10.07°). The time to maximum angles in ankle dorsiflexion and foot pronation were also quite different between these two groups. The maximum vertical ground reaction force in sprain group was significant smaller than normal group. CONCLUSIONS: The landing pattern in the subjects with recurrent ankle sprain had showed significant difference compared with normal subjects with our detail biomechanical analysis. In this study, we have revealed the adaptation of performing drop landing in the individuals with recurrent ankle sprains.