Functional implications of muscle co-contraction during gait in advanced age

Abstract

Older adults often exhibit high levels of lower extremity muscle co-contraction, which may be the cause or effect of age-related impairments in gait and associated falls. Normal gait requires intact executive function and thus can be slowed by challenging executive resources available to the neuromuscular system through the performance of a dual task. We therefore investigated associations between lower limb co-contraction and gait characteristics under normal and dual task conditions in healthy older adults (85.4±5.9 years). We hypothesized that greater co-contraction is associated with slower gait speed during dual task conditions that stress executive and attentional abilities. Co-contraction was quantified during different phases of the gait cycle using surface electromyography (EMG) signals obtained from the anterior tibialis and lateral gastrocnemius while walking at preferred speed during normal and dual task conditions. Variables included the time difference to complete the Trail Making Test A and B (ΔTMT) and gait measures during normal or dual task walking. Higher co-contraction levels during the swing phase of both normal and dual task walking were associated with longer ΔTMT (normal: R2=0.25, p=0.02; dual task: R2=0.27, p=0.01). Co-contraction was associated with gait measures during dual task walking only; greater co-contraction levels during stride and stance were associated with slower gait speed (stride: R2=0.38, p=0.04; stance: R2=0.38, p=0.04), and greater co-contraction during stride was associated with longer stride time (R2=0.16, p=0.03). Our results suggest that relatively high lower limb co-contraction may explain some of the mobility impairments associated with the conduct of executive tasks in older adults.

Dysfunctional muscle activities and co-contraction in the lower-limb of lumbar disc herniation patients during walking

“…Muscle co-contraction was defined as the common activity presented as a percentage of total muscle activity in a pair of antagonist muscles within a gait cycle 19 . Figure 2 showed the schematic of lower limb muscle co-contraction.…”

The role of attentional focus on walking efficiency among older fallers and non-fallers

“…The magnitude of differences observed in muscle co-contractions might appear to be relatively small. However, previous research by Lo and colleagues [24] demonstrated that even seemingly trivial increases in co-contraction are significantly associated with increased swing and stance durations. The clinical importance of increased co-contraction not only relates to consequential alterations in gait characteristics, but also to increased risk of falls by increasing lower limb rigidity/stiffness which impedes reactive adaptation to postural perturbations [22,25].…”

“…While existing literature suggests that even a small change (<5% change in co-contractions observed in Lo et al . [24]) might be necessary to induce significant behavioural changes and influence movement efficiency, future work should endeavour to identify such thresholds so that clinicians might avail of such measures when evaluating neuromuscular efficiency in patients.…”

Associations between lower-limb muscle activation and knee flexion in post-stroke individuals: A study on the stance-to-swing phases of gait

“…By regression analysis this study further examined the relationship between the magnitude and frequency parameters of multiple muscles and knee flexion in post-stroke gait ( Table 2 ). Although a few studies have established associations between lower-limb muscles’ coordination patterns and knee joint kinematics for healthy individuals [ 26 , 27 ], less is known about how the stroke interferes with these associations during the stance-to-swing phases of the gait cycle. The changes in muscles’ activation patterns and muscle coordination during walking has been considered to give rise to the decreased knee angles [ 5 ].…”