Reduced Pulmonary Function Association with Abnormal Muscle Activation with Knee Osteoarthritis and Increased Cardiovascular Disease Risk.

The knee OA with CVD risk group demonstrated significant reductions in vigorous physical activity compared to the isolated knee OA group.

• A total of 21 individuals with knee OA and increased CVD risk and 29 individuals with isolated knee OA were compared.
• Physical activity was assessed using the long-form International Physical Activity Questionnaire (IPAQ) in an interview format.
• The reduction was specifically observed in vigorous physical activity levels.

The knee OA with CVD risk group showed significant reductions in maximal voluntary ventilation (MVV) compared to the isolated knee OA group.

• Pulmonary function was assessed by measuring Forced Vital Capacity (FVC) and Maximum Voluntary Ventilation (MVV).
• MVV showed significant reduction in the knee OA with CVD risk group compared to knee OA alone.
• FVC was also measured but MVV was specifically highlighted as significantly reduced.

The knee OA with CVD risk group showed a lesser decrease in peak oxygen uptake compared to the isolated knee OA group.

• Cardiorespiratory fitness was evaluated using a treadmill-based cardiopulmonary exercise test (CPET) with a modified Bruce protocol.
• Peak oxygen uptake differences between groups were observed but described as a 'lesser decrease' rather than a significant reduction.
• This finding was noted alongside the more pronounced reductions in MVV and vigorous physical activity.

The knee OA with CVD risk group showed greater muscle activation of the biceps femoris (BF) during both stair ascent and descent.

• Surface electromyography (sEMG) data were collected from the major lower-limb muscles of the symptomatic limb during stair-climbing tasks performed at a self-selected, habitual speed.
• Greater BF activation was observed during both stair ascent and stair descent in the CVD risk group.
• The sEMG was described as a 'valuable non-invasive tool for identifying clinical hallmarks in knee OA patients at risk of CVD by detecting aberrant muscle activation during stair climbing.'

A negative relationship was observed between lower MVV and greater biceps femoris activation in the knee OA with CVD risk group.

• The inverse relationship between MVV and biceps femoris activation was specific to the knee OA with increased CVD risk group.
• This relationship suggests that 'superior cardiovascular function is linked to a more balanced knee muscle coordination pattern.'
• The finding links pulmonary function directly to aberrant muscle activation patterns in this at-risk population.