Although there is a plausible mechanism to support the use of exercise for plantar fasciitis, evidence from randomized controlled trials (RCTs) is limited by small sample sizes and poor methodological quality. There is insufficient evidence of any sort to recommend the use of any particular exercise or exercise duration.

• Specific foot and ankle exercises are believed to be of benefit because there is a continuous band of connective tissue between the plantar fascia and Achilles tendon, and mechanically stretching this is believed to relieve symptoms of plantar fasciitis. In addition, limited dorsiflexion of the ankle is known to be a risk factor for plantar fasciitis [McPoil et al, 2008].
• Evidence from RCTs to support the use of exercise in the treatment of plantar fasciitis is limited; CKS identified three trials of poor methodological quality:
• An RCT randomized people with plantar fasciitis (n = 94) to receive advice on performing either sustained or intermittent Achilles tendon exercises. After 4 months, both groups had improved tendon flexibility with a correlating decrease in pain compared with the baseline, but there was no significant difference between the groups [Porter et al, 2002].
• An RCT (n = 82) investigated the effectiveness of a plantar fascia-specific exercise protocol compared with an Achilles tendon-stretching protocol. After 2 years, 66 people were followed up; no significant difference was seen between the protocols [Digiovanni et al, 2006].
• An RCT (n = 92) randomized people to receive either sham ultrasound (control) or sham ultrasound and advice on performing calf muscle exercises (active intervention). After 2 weeks there was no loss to follow up, and there was no difference seen between either group in terms of 'first-step' pain, foot pain, foot function, or general foot health [Radford et al, 2007].