An Overview of Running Biomechanics
Links to Injury Prevention
Overview of Running Biomechanics
An
understanding of running biomechanics can be very beneficial to
athletes and coaches alike. Knowledge of the movement and forces present
in our bodies during running can hold the key in identifying the source
of injury and increasing performance. As technology evolves this
information is becoming more and more accessible to athletes of all
classifications. In the following article we will look at the main
biomechanical measurements which aid in identifying such injury risks,
as well as the methods of deriving such information.
Impact
forces have long been identified as possible causes of a number of
injuries during running. The impact force refers to the force at which
the body hits the ground during foot strike. These forces occur at
varied intensity dependant on a number of factors such as position and
angle of the foot at first point of contact. There are a number of
different styles of running, the main variation being the point of
contact with the ground, i.e. heel, midfoot and forefoot running.
Ongoing research aimed at concluding on “the best” running style is both
varied and conflicting. Each style has advantages and disadvantages but
none can be judged as optimal as every athlete is different. Arguably
the best advice seems to be to run the way which feels natural to you
and ensure your body is adequately conditioned to deal with the forces
and movements involved.
When
assessing running biomechanics another key area is the understanding of
the movement of the foot when it is in contact with the ground. This
typically involves the foot naturally rolling from a lateral to a
neutral position and pushing off centrally at the forefoot. This
“rolling” action or pronation, is a much hyped phenomena by running shoe
companies whom make shoes with denser midsoles to help to slow down the
rate of pronation with the aim of reducing risk of injury. It is
important to note that pronation is a natural shock absorbing mechanism
of the foot. However, problems may occur when this rolling motion occurs
too quickly and excessively for the associated leg and foot muscles to
deal with. This excessive foot motion would cause increased Q-angle (hip
to knee cap angle) which would in turn create ITB tightness. This issue
is more prevalent in women than men owing to wider hip-knee angle in
women. Excessive pronation alone is unlikely to directly cause an injury
and it is more likely a combination of the factors which we have
discussed in this paragraph along with poor postural alignment and
excessive training loads.
Variations of Running Styles
As
mentioned above there are a number of different styles of running, the
most common being rearfoot (heelstrike), midfoot and forefoot. Much has
been written of these different types of running styles but
understanding of the variations is often vague. The following is a brief
overview of each type and the advantages and disadvantages of each
respectively.
A rearfoot strike or heelstrike is the most prevalent style of running
which approximately 85% of people utilise. Initial centre of pressure
(COP) occurs in the first third of the foot. The foot naturally rolls
from the outside to the inside and pushes off the ball of the foot. An
initial impact is present as the heel strikes the ground which is
evident in figure 1. The graph shows a typical force (kg/f) vs
time curve present during a heel strike. As the foot is in front of the
body at initial contact there is increased tibial acceleration and
ankle joint stiffness. Typically common running injuries associated with rearfoot striking are anterior tibial syndrome (shin splints), patellofemoral pain syndrome (runner’s knee) and stress fractures of the tibia, fibula and metatarsal bones. 
A forefoot strike is classified as
having the initial COP in the front third of the foot. The hips and
knees are aligned with the foot on landing with increased joint flexion.
This will result in increased cadence and decreased stride frequency.
As shown in the figure to the right there will be a decrease in initial
impact forces and loading rate. The shock will be attenuated more so by muscles and less through bones and joints. While this means less stress on the bones there will be an increase in muscular strain of the triceps surae (calf muscles).
A
midfoot strike is present when the initial COP occurs in the middle
third of the foot with the heel and ball of the foot landing
simultaneously. There is normally an impact peak, albeit to a lesser
extent to a heel strike. Increasing numbers
of running shoes are available to accommodate such running style. Look
for a lower ramp angle shoe with an 8mm heel to toe differential.
Running Shoe Technology
Running
shoe companies in conjunction with scientists and engineers are
constantly researching running biomechanics and developing their
technologies accordingly. At present there are substantial differences
of opinion on the best type of running shoes, an issue creating
vociferous debates within the running community. “Barefoot” and minimal
footwear has reinvigorated in recent years and is now a significant part
of the market. As there are such variations in running shoes at
present, it is important to have a clear understanding of what a running
shoe offers before deciding to utilise it. Luckily there are is
multitude of running specialist retailers available to offer you such
advice in selecting the best shoe for your foot. Whether you run with a
heel or forefoot strike, are in need of lightweight or support, there is
certain to be a shoe to suit your needs with the vast amount of variety
available today. These such specialist retailers now utilise advanced
technology which enables high definition video analysis of treadmill
running, pressure scanning of your feet as well as lower limb and foot
physical assessments. This equipment enables the assessor to investigate
your lower limb biomechanics such as mentioned earlier in this article
and help you choose the best fit for your needs.
Important
variations to consider within running shoes include the amount of
support, stability, heel-to-toe ramp angle, flexibility and weight.
These factors can influence your running style and it is important to
understand the function of the shoe prior to purchase. It is important
not to get drawn into marketing hype by major companies on particular
shoes, rather seek advice from impartial experts who will help you
select the correct shoe regardless of price or brand. Many shoes now
offer lower ramp angle (flatter) shoes which promote more of a
midfoot/forefoot landing. This type of shoe can greatly benefit some
people but as mentioned earlier it can also cause increased strain on
the triceps surae (calf muscles) and higher pressure under the forefoot.
Pressure scanning of the foot can greatly aid in determining if this is
the best type of shoe for you.
Barefoot
running has been advocated as a means of strengthening of the foot
muscles and encouraging a better style of running. However, it has also
been associated with increased incidence of stress fractures and
abrasions of the foot. It has been hypothesized that when implemented
carefully within a running program, this type of training can offer
benefits which would not be seen within running in cushioned shoes
alone. Think of it as a conditioning session for your foot. Of course
this is not a new principle and has been used by runners for
generations, just without the current marketing hype! Research is
ongoing and it would be unfair to jump to conclusions on the barefoot
matter without conclusive evidence. Remember every individual is
different and what works for one may not work for you.
The
aim of this article was to explain the fundamental elements of running
biomechanics with the hope that it may aid you in your training and in
your future shoe choices. This has been an unbiased account of running
styles and running shoes and hopefully it well help you to draw your own
conclusion on what best suits your needs.
Thomas Twomey
Sports Biomechanist at Footpro
BSc. Sport and Exercise Science
MSc. Sport and Exercise Biomechanics
What makes the Hoka One One story even more impressive is that functionally they are great shoes to run in, BUT they look like a combo of an MBT and a corrective orthopaedic shoe designed for the vertically challenged. As keen runners the Footpro test team try to focus of function and feel, but even after miles of wear testing we still feel self conscious in our Hoka’s.
-
The
F-lite 215 and 240 are both lightweight training shoes which offer
slightly more cushioning with a 6mm heel-to-toe drop. While Inov8 shoes
have proven the mos