Intrinsic foot muscle strengthening may help to improve toe strength, balance, and functional mobility, and reduce the risk of falls in older adults

Futrell EE, Roberts D, Toole E. The effects of intrinsic foot muscle strengthening on functional mobility in older adults: A systematic review J Am Geriatr Soc. 2021;70:531-540.

Review question

Does intrinsic foot muscle strengthening improve functional mobility among adults aged 65 years old and over?

Background

Falls are the main cause of fatal and nonfatal injuries in adults aged 65 years old and over. Toe deformities and intrinsic foot muscle weakness impact stability, balance, and mobility, and are determinants of falls. Intrinsic foot muscles are muscles within the foot that provide stability and sensory inputs that other foot muscles use to produce large movements. Among healthy older adults, intrinsic foot muscles are often smaller in size and have reduced strength. Exercises that target the intrinsic foot muscles aim to enhance the alignment of the foot and toes, and impact motor control.

How the review was done

This is a systematic review of 9 studies published between 2009 and 2017 that collectively included 1674 people.

Key features of the studies:

• For the most part, participants were independent and generally healthy older adults living in the community. Participants were 65 years old and over, with an average age of 76 years old.
• Participants engaged in intrinsic foot muscle strengthening programs, which included various types of exercises that isolated or recruited intrinsic foot muscles—such as using minimally cushioned footwear while conducting daily tasks, lifting or manipulating objects with the toes, heel lifts, calf raises, and ankle inversion exercises with a resistance band. Some studies included the use of other strategies—such as foot orthoses, footwear advice, fall-prevention education booklets, and foot-care education—alongside the intrinsic foot muscle training program.
• Programs were completed 1-7 days per week for approximately 10-45 minutes and were 6 weeks to 12 months in length.
• Most studies provided home exercise programs, while some provided supervision or initial instruction by a professional (e.g., podiatrist, researcher, exercise physiologist).
• Researchers measured fall risk, fear of falls, toe strength, balance, and/or functional mobility as outcomes.
• Outcomes were most often compared to a control group (e.g., receiving usual podiatry care) or for some studies to the same adults before and after completing the exercise program.

What the researchers found

Although the included studies were quite different, several themes emerged from the data. In comparison to control groups, intrinsic foot muscle strengthening programs:

• May improve toe strength, balance, and some aspects of functional mobility.
• May reduce the risk of falls. 
• Do not appear to effect fear of falling.

The majority of the studies included were of “fair” to “good” quality.  Ultimately, more research is needed to confirm the impact of intrinsic foot muscle strengthening on these outcomes, identify the optimal frequency, duration, and length of these exercise programs, and determine whether this is an adequate standalone strategy for functional mobility.   

Conclusion

Among older adults 65 years of age and older, intrinsic foot muscle strengthening programs may be effective in improving toe strength, balance, and specific aspects of functional mobility, and may reduce falls.