At first glance, this study doesn't seem so surprising
Fifteen men performed a heavy resistance toe flexor strength training program for their feet and ankles with 90% of their maximal voluntary isometric contraction for 7 weeks (560 contractions). At the end of the 7 week program push-off strength in the feet and ankles had more than doubled, toe strength had increased 10-15% and jump distance had increased on average about 7%.(Goldmann et al., 2013)
On the face of it, it makes sense that performing high resistance training for your foot muscles would indeed be quite effective, if not a well established method of improving foot strength. That last part is where you would be wrong. It has not been a well established fact. In fact so few people considered it a possibility that almost no one has studied it.
To date, there have been few attempts to measure and strengthen foot muscles while looking at changes in function. More specifically there are even fewer studies which look at the ability to specifically strengthen toe-flexor muscles and we have been somewhat sceptical that it would make the slightest difference. Further, of those that have attempted to do this before, the results have been somewhat disappointing (Spink, Fotoohabadi and Menz, 2010; Houck et al., 2017) which makes this study even more compelling.
Previous studies had asked participants to exercise their muscles with loads and in positions that are not functional i.e. don't represent loads typical of those experienced when walking and in positions that don't represent how the joint is used during activities such as walking, running, jumping or sprinting.
This study adds enormously to the rapidly growing research surrounding the importance of foot muscle strength. All people involved with rehabilitation, including those interested in foot, knee, hip and back function need to get with the program and grow their knowledge base.
Goldmann, J. P. et al. (2013) ‘The potential of toe flexor muscles to enhance performance’, Journal of Sports Sciences, 31(4), pp. 424–433. doi: 10.1080/02640414.2012.736627.
Houck, J. et al. (2017) ‘Can Foot Exercises Alter Foot Posture, Strength, and Walking Foot Pressure Patterns in People with Severe Flat Foot?’, AOFAS Annual Meeting, pp. 1–2. doi: 10.1177/2473011417S000199.
Spink, M. J., Fotoohabadi, M. R. and Menz, H. B. (2010) ‘Foot and ankle strength assessment using hand-held dynamometry: Reliability and age-related differences’, Gerontology, 56(6), pp. 525–532. doi: 10.1159/000264655.
Makes clinical assessment of Diabetic foot weakness easy
Melbourne, September, 12, 2018 - The way in which we assess diabetic feet in a clinical setting could change dramatically with the advent of a new device to assess muscle strength in diabetes.
The ToePro Dynamometer™ is the first low cost and easily available instrument to assist in the measurement of foot strength in all people, including those with diabetes.
Foot muscle weakness can develop very early in diabetes and occurs often well before sensory changes are detected in the foot. It is one of several factors which can lead to structural changes in the toes – specifically clawing and hammering of the toes. These changes are strong predictors of increased plantar forefoot pressures and together are the number one predictor of peak forefoot pressures, essentially crushing tissues under the forefoot, a major risk factor in diabetic ulcer formation.
To read the full press release click here
It is surprising how long it has taken for significant steps to be made in understanding the relationship between foot muscle strength and foot function.
The most recent exciting paper has come from one of the world leaders in the research of intrinsic muscles and their implications in toe deformities. Karen Mickle from Victoria University, Australia has been extraordinarily productive over the last 10 years with her use of diagnostic ultrasound and dynamometers. She has collaborated with some well known researchers too including Chris Nester and Hylton Menz.
The most recent paper to have come forth from Karen has just been published in Arthritis Care & Research.
Essentially the results of this paper have confirmed what has long believed to be the case i.e. if you have toe deformities such as hallux valgus and claw toes, you are likely to have atrophic (smaller and weaker) muscles. If you have hallux valgus you have a smaller abductor hallucis, if you have lesser toe deformities (claw toes) then you had atrophy and weakness in the intrinsics attached to these.
This study collected data from 44 older adults (>60 years) with either toe deformities or not (controls). They then underwent ultrasound assessment to look at the size of the muscles in their feet with a standardized protocol.
What was particularly interesting in this study was that virtually every muscle examined (of which there were 7 different muscles examined) was atrophic relative to the controls, bar flexor hallucis longus. Take a look at the chart below:
The tricky part of this research then leads us to the next important question. Does the atrophy occur because of the toe deformity or does it lead to the toe deformity? Current evidence would point to the latter, which suggests specifically in relation to hallux valgus that prevention through exercise should happen in the early stages to stop the progression of the deformity. Once the abductor hallucis muscle moves under the 1st metatarsal it acts as a weak flexor instead of an abductor.
This interview with Dr Tom Michaud was conducted on 19th December 2017 with the "2 Movement Guys", Adam Wolf,PT and Nicholas Studholme, DC. It is an enjoyable general chat about orthoses, strength and some general lower limb management tips.
"Interested in orthotics, biomechanics, and foot function? Check out the recent podcast with Dr. Tom Michaud D.C., author of Human Locomotion: The Conservative Management of Gait-Related Disorders, as used in physical therapy, chiropractic, pedorthic, and podiatry schools around the world. Tom is a wealth of clinically relevant and easily applicable information. This is going to be worth your time!"
References in this Podcast include:
Titanium rods and tibio-femoral rotation
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