The Influence of Knee and Ankle Bracing on Lower Extremity Kinematics During a Cutting Maneuver

Abstract

Prophylactic bracing of the lower extremities has become commonplace in the athletic arena today. In the past it has been common to brace either the knee or the ankle during an athletic event to assist in the prevention of or further injury to the specific joint. It is not unusual however to brace both joints simultaneously during athletic competition. The interaction of multi-joint bracing, on the target joints as well as the hip, has not been well studied. PURPOSE: To determine the effect of four brace conditions on the lower extremity kinematics during a jogging cutting maneuver. METHODS: 18 subjects (9 male and 9 female, age = 22.8±2.0 yrs, ht = 174.7±7.6 cm, wt = 74.9±14.5 kg) participated in this study. Each subject performed 7–10 jogging cutting trials while wearing each of the four brace conditions; ankle brace only (AB), knee brace only (KB), ankle and knee brace together (ABKB) and no brace (NB). Hip and knee sagittal and frontal plane kinematics and ankle sagittal plane kinematics were assessed for each subject during each of the brace conditions. RESULTS: ANOVA (α = .05) revealed that sagittal plane ankle and hip ROM were not influenced by brace condition. Sagittal plane knee ROM was significantly reduced in the KB compared to the NB condition. Frontal plane knee ROM revealed a more varus position during the KB and ABKB conditions compared to the NB and AB conditions. The results also revealed that the hip was significantly more abducted during the KB and ABKB conditions when compared to the AB and NB conditions. CONCLUSIONS: The results indicate that the KB and the ABKB significantly influenced frontal plane hip and knee ROM and sagittal plane knee ROM during a jogging cutting maneuver. These braces may be beneficial in preventing excessive motion at the respective joint however it is important to consider their impact at the hip joint as a result of these bracing techniques. It is possible that these changes in ROM may result in subsequent changes in joint moments and or ground reaction forces.