Consequences
FHL, athletic performance and injury risk
Sport amplifies everything FHL disrupts. The dynamic imbalance disturbs performance, impact forces increase, and certain serious injuries such as the anterior cruciate ligament tear find their starting point in a predictable tilt of the foot.
The cascade all the way to performance
Physical activity amplifies the effects of FHL. With every stride, every pivot, every landing, the imbalance induced by the blocked big toe is multiplied by speed, impact and effort. What went unnoticed when walking becomes decisive when running or competing.
The biomechanical chain involved
Medial collapse, the central mechanism
Before going into the details of each discipline, one mechanism deserves to be named and understood. Most serious knee injuries in sport, notably the anterior cruciate ligament tear, share a common mechanism, the medial collapse. And behind this medial collapse lies the biomechanical signature of FHL.
At-risk mechanism
When the foot tilts, the knee follows in a spiral
During a change of direction or on landing from a jump, the foot can tilt abruptly into pronation. This tilt drags the knee into a valgus spiral combined with internal tibial rotation. This is what is known as the medial collapse, and it is the mechanism behind most ACL tears. The starting point of this tilt is a hallmark of FHL, which can be objectively demonstrated on an instrumented treadmill.
Three quarters of ACL injuries occur without contact
These injuries happen on a change of direction, a sudden deceleration or the landing of a jump. No collision, no tackle, no external force. The knee gives way on its own, and the mechanism traces back to the foot.
Four particularly exposed families of sports
Four disciplines or families of disciplines illustrate particularly well the impact of FHL on athletic performance and sports injuries. Each with its own specifics, but all with the same biomechanical origin.
Golf
In golf as in tennis, performance depends on the repeatability of the swing. That repeatability rests on a stable anchoring to the ground and the alignment of the upper body. In the presence of FHL, the center of gravity shifts backward and outward, disturbing instantaneous balance and the consistency of the stroke.
Performance consequences
Lack of stability during the swing
Variability in technique
Low-back overload pain
Running
When running, ground impact is many times greater than when walking, and the timing lag between pronation and supination becomes critical. The body is no longer positioned to cushion properly, the flexion moment increases, and the upper body is thrown forward.
Common injuries
Patellofemoral pain syndrome
Iliotibial band syndrome
Overload low-back pain
Pivoting and pivot-contact sports
Sports involving abrupt changes of direction or jump landings place intense demands on the medial collapse mechanism. The ACL tear is the most emblematic injury, but ankle sprains and meniscal tears on twisting are also common.
Common injuries
Anterior cruciate ligament tear
Severe ankle sprain
Meniscal tear on twisting
Skiing
One might think that the rigid hold of the ski boot prevents the foot from tilting. It is only an illusion. The protective effect works at first, then the foot breaks free into pronation, all the more so as the rear spoiler holds the ankle in plantar flexion. Forces become uneven and the knee pays the price.
Common injuries
ACL tear in a fall
Medial knee sprain
Tibial plateau fracture
All at-risk disciplines
Beyond the four families detailed above, many other disciplines share the biomechanical characteristics that make FHL particularly harmful. Pivoting sports, combat sports, footwork-intensive sports, dance, gymnastics — every activity that demands intensity or precision from the roll-over of the foot.
Pivoting and pivot-contact sports concerned — tennis, badminton, volleyball, dance, gymnastics, skiing, rugby, soccer, basketball, handball, combat sports, running, trail running, track and field, golf.
Identifying FHL before the injury
For athletes, the added value of diagnosing FHL is not only curative. It is above all preventive. Identifying an FHL in an athlete who practices an at-risk sport makes it possible to prevent the accident rather than repair it.
Recommendation
Any athlete who regularly practices a pivoting or pivot-contact discipline stands to gain from knowing their FHL status. A simple in-office test, the FHL stretch test, is enough to demonstrate it. For athletes who have already suffered recurrent ankle sprains or an ACL tear, this evaluation is essential before returning to sport.
The full assessment combines the clinical test in the office, gait analysis on an instrumented treadmill, and analysis of the dynamic footprint. It objectively demonstrates the tilt into pronation and quantifies the shift of the center of gravity. For regular runners, golfers and skiers, it is a preventive investment.
« Sport does not create FHL, it reveals it. And when it does, it is often through an injury that could have been prevented had we looked for it. »
Dr Jacques Vallotton, Centre Orthopédique d’Ouchy
Understanding through video
Four video sequences illustrate the impact of FHL on athletes, from the biomechanics of running to footwear choices, by way of golf and skiing.
Biomechanics of running
Footwear: minimalist or maximalist?
The professional golfer’s experience
Skiing, yesterday and today
Are you an athlete?
Assess your risk profile
Whether you are a runner, a golfer, a skier or play a pivoting sport, the mobility assessment at the Centre du pied can objectively identify a possible FHL and evaluate your risk profile.
At a glance
At-risk sports
pivoting, pivot-contact
Key mechanism
medial collapse
Hallmark injury
ACL tear
Running
runner’s knee
Diagnostic test
FHL stretch test
Reference assessment
instrumented treadmill
Further reading
Other implications and useful pages
Ankle
The athlete’s recurrent sprain and the surgical alternative of tenolysis vs ligamentoplasty.