Orthoses are designed for the many different sports in which we participate. Orthoses however are primarily prescribed for straight line movement such as walking and running. This is why you are observed performing straight line movements on a treadmill or walkway. The assumption that this movement also translates to other sports is not strictly true. in fact far from it. The reality is that most sports we participate require more complex directional change movements as well as those in a straight line.
The use of orthotics for such activities often requires a subjective approach given that many lateral movements cannot be measured and nor is there normative data on such movement. Sports where lateral movements are involved will move the goal posts on many orthotic prescriptions and often more than one pair of orthoses may be required for such activities. When changing direction the arch of the foot does need to reduce more to enable effective weight transfer to be facilitated.
Lets consider several examples of activities where straight line movement is combined with lateral or sports specific foot movement.
This image highlights the medially loaded foot position when this player is changing direction. The foot has to assume this position for bodyweight to be transferred from right to left. The use of an orthotic that works well for straight line motion control may antagonise the arch of the foot an also potentially contribute to lateral ankle sprains or instability. As can be seen in order to provide maximum stability and directional change the rugby player has rolled their foot inwards maintaining alignment with the knee which is also leaning inward.
This image of the tennis player about to move forward and change direction will impose significant lateral stresses in the foot. The rapid rotations and side to side movements (as well as backwards) can compromise many orthotic interventions.
Many players will tape or brace their ankles and certainly most professional players use some type of orthotic device.
Netball is a game that is particularly stressful on the lower limb. Due to the directional change, sudden braking and close marking, ankle sprains are one of the most common injuries netballers sustain.
Much of the players time is spent on their toes and thus the effect of an orthotic may often require more support in the mid to forefoot area. The orthotic must also complement the footwear used by the player as interestingly many still wear running shoes for added comfort and cushioning.
The sport of cycling has become incredibly popular particularly of late. In more and more countries cycling is promoted as a healthy and economic method of transportation not to mention a low injury risk form of training.
Foot motion in cycling has not been studied like it has in runners. The cyclic motion of the foot generates power through the pedal with no impact as such. An orthotic in the cycle shoe environment is frequently used to enhance performance just as much as it is used to treat or prevent injuries. Generally the cycle orthotic is quite hard and motion controlling given the cyclist wants power delivered quickly to the pedal and crank. Such orthotic devices are usually much slimmer to fit inside the snug cycle shoes.