Comparing the Effects of Upper and Lower Body Aerobic Exercise on Pain in Individuals With Chronic Knee Pain

Pain has a multifaceted nature encompassing peripheral drivers (i.e. loading), peripheral and central nervous systems (peripheral and central sensitisation) and cognition (i.e. fear). Most recently, evidence supports that chronic pain in OA may cause alterations to the peripheral and central nervous systems. Despite this, current research has mainly targeted peripheral drivers (usually weight reduction) and cognition (educational programmes) with results highlighting that such methods are not always effective in reducing pain. It would be useful to provide a wider range of choice when prescribing exercise for OA for those which the current prescription is ineffective or un-desirable.

Acutely, both localised and generalised exercise involving the knee joint in individuals with KOA is known to increase symptomatic pain in some. However, research suggests that diverting exercise away from the affected joint may improve pain perception and pain experience in a subset of individuals by targeting cognition (attention away from the joint) and alleviating peripheral drivers of pain (reduced loading) while still presenting systemic physiological benefits that come with acute aerobic exercise which target peripheral and central sensitisation. Currently, there is only one study (Burrows et al, 2014) which has compared the effects of acute upper vs. lower body exercise on pain perception in KOA patients and this was employing resistance exercise. Although this study found positive effects of upper body exercise on pain, this pain was experimentally induced, and symptomatic pain was not measured.

The investigators aim is to determine the effects of a single bout of upper body aerobic exercise on experimentally induced and symptomatic pain in individuals with chronic knee pain in comparison with lower body aerobic exercise.

Inclusion criteria

• Aged ≥45 years
• Male or female
• Knee pain for ≥3 months
• Activity related joint pain
• No joint related morning stiffness, or morning stiffness lasting less than 30 minutes.

Exclusion criteria

• Specific joint injury within the last 6 months
• Inability to undertake cycling exercise
• Use of anti-inflammatory medication
• Smoker (or having quit <6 months ago)
• Osteoarthritis at any upper body sites that would affect ability to complete arm-cycling exercise.