Dorsiflexion....underrated???

In my experience as a coach and as an athlete, I haven't seen too much emphasis placed on dorsiflexion by many coaches, and only one or two have explained some of the benefits in detail in my presence. I think most individuals involved in sprinting believe that dorsiflexion warrants some consideration, but I'm not convinced (this may be a sign of my arrogance) that all those individuals understand the reasoning. I wanted to provide some information regarding my understanding of dorsiflexion and some of the ways it can benefit a sprinter.


What is dorsiflexion?

Very simply dorsiflexion is a position in which the toes are pulled up towards to the shin.

A diagram showing the difference between dorsiflexion and plantarflexion.

Note the dorsiflexed position of the front foot held by both Usain Bolt and Justin Gatlin.

Shortening of lever length.

If you have studied any physics, you are probably aware of the principle that a short lever is a fast lever.  By dorsiflexing, you are, albeit minimally, shifting the centre of gravity of the lower segment of the leg closer to the knee, effectively shortening the lever. This then allows that segment of the leg to fold at the knee towards the femur more quickly. The knock on affect of this, is that now the centre of mass of the upper segment of the leg is now closer to the hip, effectively shortening this lever, which allows this segment to swing forwards more quickly, until the thigh blocks. Whilst flight times are relatively similar across sprinters of varying standards, it has been proposed that better sprinters prepare for subsequent ground contacts earlier in the stride cycle, which can make these contacts more powerful and efficient. Through this mechanism, the athlete is able to prepare for the next contact earlier.


Reduction of hamstring stress.

A basic understanding of anatomy is all that is required to understand that to move into a plantarflexed position requires a contraction of the gastrocnemius. To relax the gastrocnemius, dorsiflexion is required. The hamstring is used throughout a large proportion of the stride cycle, serving two functions, knee flexion and hip extension. However, if the gastrocnemius is relaxed, it can be untilised in knee flexion, therefore taking some of the onus away from the hamstring. It doesn't require too much of a background in sprinting to know that hamstring injuries are fairly common, so anything that can be done to take stress away from them is likely beneficial.

Knee flexion.

Hip extension.

A simple demonstration that coach Simon Duberly taught me makes it very easy to see the impact that dorsiflexion can have upon both the speed at which the leg can be moved through the air and the stress it removes from the hamstring. Have an athlete stand next to a wall and perform the same movement under two slightly different conditions. The athlete should be standing fairly upright with perhaps a slight forward lean. In both scenarios, the athlete will stand on one leg, using the wall to help them balance and with the free leg, they will lift their heel to their buttock ten times as quickly as possible, whilst keeping their knees together. In scenario A, ask the athlete to maintain a dorsiflexed position. In scenario B, ask the athlete to repeat the movement, but this time, ask them to maintain a plantarflexed position. The majority of the time in my experience, provided the drill is performed correctly, when you ask the athlete what they notice, they will give you two pieces of information without having to be guided towards the answer. They will tell you that in scenario A, they could lift and lower the heel more quickly, and that it feels easier on their hamstring.

Have the athlete start in the above position.

In scenario A, the athlete raises their heel, whilst in a dorsiflexed position, to their buttock and back down, ten times as quickly as possibly.

In scenario B, the athlete repeats the movement, but this time they will hold their foot in a plantarflexed position.

Increased knee lift.

Reciprocal inhibition is a condition whereby muscles work in antagonistic pairs. Think of the upper arm and the biceps and triceps. The biceps essentially allow the elbow to flex, whilst the triceps allow it to be extended. In order for either muscle to perform the movement as efficiently as possible, the opposing muscle group needs to be completely relaxed. If elbow flexion takes place whilst the triceps is still firing, the biceps will have to work that much harder to bring about the desired movement.

I mentioned earlier that the hamstring serves two functions during sprinting, knee flexion (both concentric and eccentric) and hip extension. In order to lift the knee, hip flexion must occur, but the hamstring acts as a hip extensor, an antagonistic pairing. However, referring back to dorsiflexion's role in allowing the gastrocnemius to assist the hamstring in knee flexion, thereby allowing it some recovery time and a greater degree of relaxation, the hip flexion can take place with less opposing muscle activity from the hamstring to overcome. The result is a higher knee lift, which allows for a more forceful downward movement of the foot later in the stride cycle, leading a stronger ground contact on the following stride.

In summary, these are three of the key benefits of dorsiflexion to sprinters. Furthers probably exist in terms of an Achilles pre-stretch and quality of force application upon ground contact. These are areas where perhaps I can develop my own knowledge. I stress the importance of dorsiflexion through all my drills as I believe it is a prerequisite position for a sprinter wishing to realise their potential.