Don’t try to “soften” the Plantar Fascia or Achilles Tendon in patients with plantar fasciopathy!

Plantar heel pain or plantar fasciopathy (PF) is a common foot condition affecting approximately 9.6% of the population. It is commonly observed in individuals over 50 years of age and athletes. PF is characterized by pain in the heel region, particularly upon initiating activity after a period of rest, and can worsen throughout the day, impacting sports performance and daily activities. The pathogenesis of plantar fasciopathy is likely multifactorial, involving mechanical overload and excessive tension that can cause microscopic tears in the plantar fascia.

A study from Brazil compared the stiffness of various tissues, including the plantar fascia, Achilles tendon, and triceps surae, between individuals with PF and those without the condition.

The researchers recruited thirty-nine individuals diagnosed with PF and a control group without a history of PF. They assessed myofascial stiffness, range of motion, and conducted clinical tests. The results revealed intriguing differences between the two groups.

Using “IndentoPro” which measures tissue stiffness, the study found that Individuals with PF exhibited lower stiffness in the insertion of the Achilles tendon on the symptomatic limb compared to the corresponding limb in the control group. Additionally, they displayed reduced stiffness in the plantar fascia on the symptomatic limb compared to the asymptomatic limb. Furthermore, individuals with PF had lower stiffness in the region 3 cm above the Achilles tendon insertion compared to the control group.

This finding seems to be contradictory to the common understanding in manual therapy, in which the pathological tissue is assumed to be stiffer than usual, and a therapist aims to soften the tissue to move it back towards a painfree normality.

The study also examined clinical performance in individuals with PF. It found that they demonstrated fewer repetitions in the heel rise test and the step-down test compared to the control group, indicating a decrease in functional abilities.

These findings suggest that individuals with PF experience decreased tissue stiffness in the Achilles tendon insertion and plantar fascia. Notably, the stiffness reduction was more pronounced in the Achilles tendon among individuals with PF compared to those without the condition. Additionally, the clinical tests revealed lower performance in individuals with PF, indicating potential functional limitations.

WHAT CAN CLINICIANS LEARN FROM THIS STUDY OUTCOME?

Robert Schleip, who is a co-author, and advisor of this study wrote:

1) This is one more confirmation that Plantar Fascia and Achilles Tendon are intimately linked in an in-series force transmission mechanisms (similar to the patellar tendon and the rectus femoris); and it therefore makes sense to aways treat both of them, even if only one of them happens to be in a painful condition. I.e. if you Plantar Fascia hurts, please treat also the Achilles tendon. And if the Achilles tendon hurts, please also treat the Plantar Fascia.

2) It does not make much sense to aim to “soften” these tissues with therapeutic stimulation. The pain-inhibiting and beneficial effect of mechanical stimulation on these tissues – whether in foam rolling, deep tissue massage, stretching, or with vibratory tools – is probably not due to tissue softening but rather to other physiological processes, such as a change in the biochemistry, in water binding, or in neural processing.

I look forward to continue this research direction, particularly to find out in future studies when and how exactly (morphologically) the described “softening” of the painful fascial tissues on this end of the human body do occur. Possibly these subsequent steps will allow us to also give recommendations how these pathologies may be prevented, i.e. before they start to manifest.