Some biomechanical aspects of the foot and ankle in athletes … · 2016-04-04 · Some...
Transcript of Some biomechanical aspects of the foot and ankle in athletes … · 2016-04-04 · Some...
Some biomechanical aspects of the foot and ankle in athletes with and without shin splints Jukka T. Viitasalo, PhD and Martti Kvist, MD
Taylor Dourney, Caroline Kolada, Kathleen McAuliffe, Kristin Pawlak, Kirby van Erkel
The leg is composed of five distinct regions Upper leg Knee Lower leg Ankle Foot
The Lower Extremity
Medial Tibial Stress Syndrome (MTSS)
“Shin splints”
Pain in the anterior part of the lower leg after repetitive overuse
Most common in athletes, specifically runners
Why should we care?
Shin splints account for nearly 60% of all overuse injuries of the leg
About 10-20% of runners will experience shin splints at least once during their career
Why do shin splints occur?
Etiology of most overuse injuries is multifaceted
Three categories for cause of pain
Bone origin
Vascular origin
Soft tissue origin
Major Etiological Factors
Training methods
Training surfaces
Muscle dysfunction and inflexibility
Shoe design
The biomechanics of running
Biomechanics of Shin Splints
Subtalar joint’s triphase motion
Excess and abnormal pronation
Amount and timing of movement
Purpose of the Study
Comparisons between athletes with and
without shin splints
Mobility of subtalar joint
Position of lower leg and heel
Angular displacements of lower
leg and heel
Biomechanics of Running
Swing phase
Stance phase
Subtalar Joint
Inversion/Supination
Rigid support
Initial contact
Terminal stance
Eversion/Pronation
Shock absorption
Loading response Midstance
Abnormal Mobility of Subtalar Joint
Overpronation
Flat feet, uneven surfaces, repetitive jumping
Results of the Study
Increased eversion and inversion → shin splints
Are some people at a higher risk for MTSS?
After studying many risk factors, only Body Mass Index (BMI) showed a significant correlation to developing shin splints
Higher BMI = higher risk of shin splints
(Plisky et. al, 2007)
Does sex matter?
Multiple studies show females more likely to acquire MTSS than males
Women are 1.5 to 3.5 times more likely to develop under same conditions and have MTSS worsen to stress fractures
In part due to lower bone density and increased chances of osteoporosis in women
The Evolution of Shin Splints
Chimpanzees do not experience, but likely that some hominins did. Unique to bipedal humans
Humans have arch in foot, supported by the plantar fascia
With larger arch, risk for lower leg injuries like shin splints increases
arch
Is it really shin splints? Often a primary general diagnosis, specific diagnosis difficult
Normally diagnosed by physician palpation of medial, distal shin
If chronic, extra tests required to rule out more severe conditions MTSS
General Diagnosis
If chronic...
Severe MTSS
X-Ray/bone scan
Neurological Exam
MRI
Is prevention possible?
Since experts do not agree upon cause of MTSS, it makes prevention very difficult
Focus is on controlling proposed risk factors
Controlling all risk factors in all athletes is impossible
Promising Ways to Control Risk Factors Replace running shoes every 300-600 miles
Graduated running programs
Shock-absorbent & pronation controlled insoles
Orthotic Supports Stabilizes subtalar joint (pronation-control)
Shock-absorbing insoles
Redistributes pressure on the bottom of the foot
Custom or over-the-counter
Athletic training clinicians should... Increase strength & endurance of soleus
Control over pronation
Promote adequate shock absorption & maintenance of proper foot biomechanics
Work with coaches to commit 1 day a week to cross-training to relieve stress
Sources http://ajs.sagepub.com/content/11/3/125.full.pdf+html http://dubinchiro.com/2013/10/shin-splints/ http://dubinchiro.com/2013/10/achilles-tendinopathies-in-runners-causes-treatment-and-prevention/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2386425/pdf/attr-43-03-316.pdf
Aydog S, Tetik O, Demirel H, Doral M. Differences in sole arch indices in various sports. British Journal
of Sports Medicine. 2005;39(2).
Latimer, B. The perils of being bipedal. Annals of Biomedical Engineering, 33 (2005), pp. 3–6
Plisky MS, Rauh MJ, Heiderscheit B, Underwood FB, Tank RT. Medial tibial stress syndrome in high school cross-country runners: incidence and risk factors. J Orthop Sports Phys Ther. 2007;37(2): 40–47. Yates, B., White, S. (2004). The incidence and risk factors in the development of medial tibial stress syndrome among naval recruits. American Journal of Sports Medicine, 32(3), 772–780.