Cannabis users walk differently.

We all have experienced or viewed the alcohol impaired gait at some point in our lives, the sloppy malcoordinated limb and torso movements. There are some classic observable characteristics there that many of us are familiar with.  But what about cannabis gait ?

"The research from the University of South Australia, published in the journal Drug and Alcohol Dependence, found those who smoke cannabis tend to move their shoulders less and elbows more as they walk. The pilot study also found marijuana users swing their knees more quickly during walking. The differences in gait were small and found in people who smoked a light or moderate amount of cannabis. Some changes were so small it was impossible for a specialist to detect."

However, the thing we found interesting was the papers final question, as to whether the subtle gait changes over a longer period of time would increase or become more apparent.

Not insinuating that Mystic Mac is a user, but he sure does help us hit our "reduced antiphasic gait" home with a glorious demo !

*We have seen this variation in arm swing gait many times before. We have discussed numerous times that when there is a reduction in the normal shoulder and pelvic "girdle" counter rotations, the normal antiphasic gait that presents us with the clearly obvious opposite arm-leg swings, we lose the ability to tap into these oscillations that afford us this free arm and leg swing.  So, when these girdle rotations are reduced, the limb movement has to come from further down into the limb, from elbow movement, a sort of casting the lower arm forward from biceps and triceps activity and from a kicking forward of the lower leg from quadriceps activity instead of hip flexion-extension activity.

We have mentioned this reduction in the normal antiphasic gait many times previously in our arm swing articles. Particularly, the reduction in the amplitude of the separation in the shoulder-pelvic girdle oscillations in those with spine pain. The more the spine is "twisted and wrung out" by these opposite swings, the more spinal motor unit compression, which can increase spine pain. Just search our blog for "arm swing" (30+ articles on the topic there). Thus the question remains , why does cannabis cause this same reduction?

Gait affects everything, and everything seems to affect our gait.

http://www.9news.com.au/national/2017/09/01/15/25/marijuana-users-walk-differently-australian-study-claims

Kicking gait?

And now… A question from a reader….

 Dr Allen- There are a few questions troubling me. The first one concerns the loss of the ankle rocker phase of gait which can have implications further up the kinetic chain. It concerns the interplay of gastroc and soleus. Is it possible for gastrocnemius to work as a knee extensor when the foot is in the closed chain position - especially if the bodies centre of mass has advanced in front of the knee joint ? Thanks - RB

Hi RB_____,

yes it is possible…….it is a retrograde movement as you have described.
it is not commonly seen, but can be, and usually manifests itself, in one of 2 ways.

Typically the client is more ligamentously lax than others……..and they tend to have a “kicking” type gait, where they thrust the leg out in front, like kicking a ball, with each step forward. This causes a heavy heel strike and locks the knee in preparation for midstance, and then follows your thinking. By the way, this client also seems to like standing in a hyperextended knee position at rest.

We remember that the gastroc soleus group begins to fire in the first 10% of stance phase (it is acting as a knee extensor here); to promote eccentric deceleration of the forward moving tibia, and continues to fire until terminal swing. It is believed the soleus provides much of the deceleration force and the gastroc assists in inverting the ankle at midstance and primarily flexes the knee at pre swing, just prior to toe off (Nordin, Frankel 2001). If the gastroc /soleus group fires prematurely, or excessively, particularly in prior to midstance, then we see the action you describe, and it manifests itself as premature heel rise and loss of ankle rocker.

A sudden hyperextesion at midstance or later, in a neurologically competent individual, is unlikely, as he force is too abrupt at this point and there is too much of a mechanical disadvantage.

We hope this helps explain things a bit. Please email us back if it doesn’t!

Uber Geeks, Shawn and Ivo