Introduction People with diabetic peripheral neuropathy (DPN) are more likely to fall than age-matched controls, and are particularly at risk during the physically demanding task of stair descent. The timing of lower limb muscle activations is fundamental to controlling joint movement and enabling a safe descent, but such timings may be adversely affected by diabetes and DPN. The aim of this study was to investigate the effect of DPN and diabetes on muscular activations during stair descent. Methods 12 DPN patients, 12 diabetic patients without neuropathy (D) and 10 age and BMI-matched controls (C), descended a 7 step staircase. Electromyographic (EMG) activity was recorded from the vastus lateralis (VL) and biceps femoris (BF), medial gastrocnemius (MG) and tibialis anterior (TA) muscles, from which onset, cessation, and duration timings relative to foot-step contact (FSC) were obtained (Figs. 1 & 2). A one-way ANOVA was used to analyse between group differences (significance p<0.05). Results The MG muscle was activated significantly earlier relative to FSC by the DPN group compared to controls, but the D group displayed similar activation timings to controls (Fig. 1). Both the DPN and D groups activated the TA muscle significantly closer to FSC than the C group. The DPN group activated the MG and TA muscles for significantly longer than the C group (Fig. 1). There were no significant differences between groups for the onset of VL or BF muscle activation (Fig. 2). DPN and D patients activated the VL muscle for a similar duration to the C group, but the DPN group activated the BF muscle for a significantly longer duration compared to the C group (Fig. 2). Discussion Differences in muscle activation strategy were observed primarily at the ankle joint, with the DPN group activating MG and TA muscles significantly earlier and later, respectively, than the C group. This modified activation strategy may indicate increased dependence on the plantar flexors to control ankle dorsiflexion upon FSC during stair descent. The DPN group also activated the MG and TA muscles for longer compared to controls, which is likely a mechanism to improve ankle stabilisation. The D group displayed alterations to muscle activation in the same pattern to that of the DPN group, but to a lesser extent, highlighting the progressive nature of diabetes. The DPN group activated the BF muscle for a longer duration than the C group, but no other differences in muscle activation were observed between groups at the knee joint, further highlighting the predominantly distal adaptation of the stair descent strategy adopted by patients with DPN.