Knee proprioception and strength and landing kinematics during a single-leg stop-jump task.

CONTEXT: The importance of the sensorimotor system in maintaining a stable knee joint has been recognized. As individual entities, knee-joint proprioception, landing kinematics, and knee muscles play important roles in functional joint stability. Preventing knee injuries during dynamic tasks requires accurate proprioceptive information and adequate muscular strength. Few investigators have evaluated the relationship between knee proprioception and strength and landing kinematics. OBJECTIVE: To examine the relationship between knee proprioception and strength and landing kinematics. DESIGN: Cross-sectional study. SETTING: University research laboratory. PATIENTS OR OTHER PARTICIPANTS: Fifty physically active men (age = 26.4 ± 5.8 years, height = 176.5 ± 8.0 cm, mass = 79.8 ± 16.6 kg). INTERVENTION(S): Three tests were performed. Knee conscious proprioception was evaluated via threshold to detect passive motion (TTDPM). Knee strength was evaluated with a dynamometer. A 3-dimensional biomechanical analysis of a single-legged stop-jump task was used to calculate initial contact (IC) knee-flexion angle and knee-flexion excursion. MAIN OUTCOME MEASURE(S): The TTDPM toward knee flexion and extension, peak knee flexion and extension torque, and IC knee-flexion angle and knee flexion excursion. Linear correlation and stepwise multiple linear regression analyses were used to evaluate the relationships of both proprioception and strength against landing kinematics. The α level was set a priori at .05. RESULTS: Enhanced TTDPM and greater knee strength were positively correlated with greater IC knee-flexion angle (r range = 0.281-0.479, P range = .001-.048). The regression analysis revealed that 27.4% of the variance in IC knee-flexion angle could be accounted for by knee-flexion peak torque and TTDPM toward flexion (P = .001). CONCLUSIONS: The current research highlighted the relationship between knee proprioception and strength and landing kinematics. Individuals with enhanced proprioception and muscular strength had better control of IC knee-flexion angle during a dynamic task.

Local anaesthetics use does not suppress muscle activity following an ankle injection.

PURPOSE: To determine if peroneus longus (PL), peroneus brevis (PB), medial gastrocnemius (MG) and tibialis anterior (TA) muscle activation patterns during inversion perturbation and running tasks are suppressed following lidocaine injection to the anterior talofibular (ATF) and calcaneofibular (CF) ligament regions. METHODS: Fourteen recreationally active male subjects (age, 24.8 ± 2.9 years; height, 177.0 ± 6.0 cm; mass, 77.7 ± 6.7 kg) participated. Testing was performed under five injection conditions to the ATF and CF regions: 1 ml saline, 1 ml lidocaine, 3 ml saline, 3 ml lidocaine or no injection. Following injection condition, traditional ankle taping was applied. Electromyography patterns of the PL, PB, MG and TA were collected while subjects performed continuous lateral jumps on a custom-built device which elicited an ankle inversion perturbation and treadmill running (3.35 m s(-1), 0.5 % incline). RESULTS: No significant differences were demonstrated in muscle activation patterns of the PL (n.s.), PB (n.s.), MG (n.s.) or TA (n.s.) for any variable across injected conditions during both tasks. Statistical power was 0.214-0.526 for the PL, 0.087-0.638 for the PB, 0.115-0.560 for the MG and 0.118-0.410 for the TA. CONCLUSIONS: Injection of lidocaine up to 3 ml to the ATF and CF regions did not suppress muscle activity of the PL, PB, MG or TA during the inversion perturbation or running tasks. Injection up to 3 ml of 1 % lidocaine to the ATF and CF regions may be used without sacrificing the muscle activation patterns about the ankle. This finding is clinically relevant since the use of the injection does not put the patient at any higher risk of reinjury to the site.

Reliability and precision of hip proprioception methods in healthy individuals.

OBJECTIVE: The goal of this study was to establish the intrasession and intersession reliability and precision of threshold to detect passive motion (TTDPM), force sense (FS), and active joint position sense (JPS) tests for the hip in healthy individuals. DESIGN: Descriptive laboratory study. SETTING: Research laboratory. PARTICIPANTS: Data were collected on 20 subjects between the ages of 18 and 30 years. They were physically active and had no history of major lower extremity injury or surgery or hip injuries. INTERVENTIONS: Threshold to detect passive motion, FS, and active JPS were measured using a Biodex System 3 and a Vicon Motion Analysis System. MAIN OUTCOME MEASURES: Error scores were calculated as the absolute difference between the reference and reproduction values. Intraclass correlation (ICC) and standard error of measurement (SEM) were used to assess intrasession and intersession reliability and precision. RESULTS: Adduction showed good reliability for JPS, with an intersession ICC (SEM) of 0.753 (0.248 degrees). For TTDPM, abduction showed an intrasession ICC (SEM) of 0.825 (0.256 degrees) and adduction had an intrasession ICC (SEM) of 0.765 (0.266 degrees). The intersession ICCs (SEM) were as follows: flexion 0.810 (0.143 degrees), extension 0.777 (0.195 degrees), abduction 0.906 (0.176 degrees), and adduction 0.893 (0.144 degrees). Flexion showed a good intersession ICC for FS: 0.764 (0.932 Nm). CONCLUSIONS: Results indicate that a reliable and precise method of measuring hip TTDPM has been established. Further investigation is necessary to develop reliable and precise measurement methods for FS and active JPS of the hip and to identify if TTDPM is related to hip kinematics, hip kinetics, and muscle activation about the hip during functional tasks.