Effects of prolonged walking with body borne load on knee adduction biomechanics

Prolonged Load Carriage Impacts Magnitude and Velocity of Knee Adduction Biomechanics

“…The stiffer limb may transmit greater impact forces to the soft-tissue structures of the lower limb in general and the knee joint specifically [10], increasing the likelihood of soft-tissue injury [11]. In response to the heavy body borne loads service members reportedly adopt hazardous knee Biomechanics 2021, 1 347 biomechanics [12,13], potentially further elevating the risk of soft-tissue damage and OA development [14].…”

“…Of particular importance, are knee adduction biomechanics. Specifically, the magnitude of knee adduction angle and moment, and varus thrust (rapid lateral knee motion, i.e., adduction, immediately following heel strike [16]) have been directly implicated in the pathogenesis of knee OA [17,18], and are reported to increase when walking with heavy body borne loads [12,13]. Individuals with visually confirmed varus thrust (>2.5 degrees [16]), for instance, are four times more likely to develop knee OA during unloaded walking [18].…”

“…This continual increase in GRF may require a concomitant rise in muscular effort to stabilize the knee joint [21] and leads to exercise induced muscular weakness, resulting in lower limb biomechanical alterations [7,22]. Specifically, during prolonged periods of walking with a body borne load, the magnitude of knee flexion and adduction joint angle and moment is reported to increase [13,23]. During a recent prolonged load carriage task, individuals exhibited a significant increase in the magnitude of knee adduction angle and moment after 30 min of walking and the addition of 15 kg and 30 kg body borne loads [13]; yet it is unknown whether walking for extended periods with heavy body borne load leads to increases in velocity of knee adduction biomechanics.…”

“…Specifically, during prolonged periods of walking with a body borne load, the magnitude of knee flexion and adduction joint angle and moment is reported to increase [13,23]. During a recent prolonged load carriage task, individuals exhibited a significant increase in the magnitude of knee adduction angle and moment after 30 min of walking and the addition of 15 kg and 30 kg body borne loads [13]; yet it is unknown whether walking for extended periods with heavy body borne load leads to increases in velocity of knee adduction biomechanics. Considering decreased knee extensor and flexor strength is purportedly associated with increased peak knee adduction velocity for individuals with knee OA [24], and exercise-induced muscular weakness may lead to similar increases in knee adduction velocity, particularly when walking with heavy body borne load.…”

“…Varus knee alignment is associated with larger peak knee adduction moments and greater magnitude of varus thrust during unloaded walking [26], but it is currently unknown whether static knee malalignment is associated with hazardous alterations in knee adduction biomechanics during prolonged load carriage. To build upon recent load carriage research [13], this study sought to determine whether body borne load and duration of walking impacted the magnitude and velocity of knee adduction biomechanics for individuals with and without varus thrust and whether static knee varus malalignment differed for individuals with and without varus thrust. We hypothesized that varus thrust participants would exhibit greater increases in magnitude and velocity of knee adduction biomechanics with the addition of body borne load and walk duration than the control participants, and static knee varus malalignment compared to individuals without varus thrust.…”