Prolonged Load Carriage Impacts Magnitude and Velocity of Knee Adduction Biomechanics

Gaervyn J Salverda,Samantha M Krammer,Tyler N Brown,Micah D Drew

doi:10.3390/biomechanics1030029

Abstract

Background: This study determined whether prolonged load carriage increased the magnitude and velocity of knee adduction biomechanics and whether increases were related to knee varus thrust or alignment. Methods: Seventeen participants (eight varus thrust and nine control) had knee adduction quantified during 60-min of walking (1.3 m/s) with three body-borne loads (0 kg, 15 kg, and 30 kg). Magnitude, average and maximum velocity, and time to peak of knee adduction biomechanics were submitted to a mixed model ANOVA. Results: With the 0 and 15 kg loads, varus thrust participants exhibited greater magnitude (p ≤ 0.037, 1.9–2.3°), and average (p ≤ 0.027, up to 60%) and maximum velocity (p ≤ 0.030, up to 44%) of varus thrust than control, but differences were not observed with the 30 kg load. The 15 and 30 kg loads led to significant increases in magnitude (p ≤ 0.017, 15–25%) and maximum velocity (p ≤ 0.017, 11–20%) of knee adduction moment, while participants increased magnitude (p ≤ 0.043, up to 0.3°) and maximum velocity (p ≤ 0.022, up to 5.9°/s and 6.7°/s) for knee adduction angle and varus thrust at minutes 30 and 60. Static alignment did not differ between groups (p = 0.412). Conclusion: During prolonged load carriage, all participants increased the magnitude and velocity of knee adduction biomechanics and the potential risk of knee OA.

Highlights

Group exhibited a greater magnitude of varus thrust at minutes 0, 30, and 60 compared to CON participants, but no group differences were observed at any time point with the 30 kg load (p > 0.05)
The VT participants increased varus thrust magnitude at minute 60 compared to minute 0 with the 15 kg load (p = 0.013, d = 0.15), but their varus thrust magnitude did not differ between any time point with either the 0 kg or 30 kg load (p > 0.05); whereas CON exhibited no significant difference in varus thrust magnitude between any time point with any of the loads (p > 0.05)
The VT participants increased average varus thrust velocity at minute 60 compared to minute 0, with the 15 kg load (p = 0.031, d = 0.52), but average velocity did not differ between any time point with either the 0 kg or 30 kg load (p > 0.05)

Summary

Introduction

Knee OA development typically causes loss of joint function and an increase of pain, leading to long term disability and medical discharge for service members [1]. It is imperative researchers understand knee biomechanics that contributes to service members’ elevated rate of OA at the joint. This study determined whether prolonged load carriage increased the magnitude and velocity of knee adduction biomechanics and whether increases were related to knee varus thrust or alignment. Conclusion: During prolonged load carriage, all participants increased the magnitude and velocity of knee adduction biomechanics and the potential risk of knee OA

Results

Discussion

Conclusion