Ankle co-contraction rises with age, trading walking efficiency for stability in 107 adults aged 26-86

The study collected 3D motion and EMG data from 107 healthy adults walking at self-selected speeds. Older participants exhibited greater simultaneous activation of ankle dorsiflexors and plantarflexors at heel strike, increasing joint stiffness by measurable margins. This safety-first pattern reduced push-off power, producing shorter steps and slower velocities while elevating metabolic cost. The design was cross-sectional with no longitudinal follow-up, limiting causal claims about progression.

Prior gait studies, including Hortobágyi et al. (2011) in the Journal of Applied Physiology on older adults' co-activation and a 2018 meta-analysis in Gait & Posture, consistently link this strategy to fall risk and fatigue. The Flinders work adds precision by isolating ankle mechanics rather than whole-limb measures and ties the change explicitly to reduced forward propulsion. It also highlights why strength training alone may fail without coordination drills that recalibrate muscle timing.

Policy implications follow directly: Australian aged-care guidelines could shift from generic strength programs to targeted balance-plus-coordination interventions such as tai chi or reactive stepping, potentially delaying mobility loss. A randomized trial measuring co-contraction reduction and falls over 12 months would test whether reversing the pattern improves real-world independence.

Next steps include wearable-sensor validation in free-living conditions and testing whether early intervention in the 50-65 age band prevents entrenched co-contraction patterns.