Treadmills, motorized or nonmotorized can have some pitfalls. Here are seven of our biggest concerns.
More on non motorized treads from Mike Reinold which came to my attention via Scott Tesoro (thanks!).
1. Watch out for how much ankle dorsiflexion(and great toe extension) your client has to be able to take advantage of the “curve”
2. The treadmill, whether motorized or not, is constantly moving, opposite the direction of travel. With the foot on the ground, this provides a constant rate of change of length of the gastroc/soleus (ie, it is putting it through a slow stretch); so, once the muscle is activated, it contracts for a longer period of time because of the treadmill putting a slow stretch on the gastroc and soleus.
3. The moving deck also has a tendency to put the ankle in dorsiflexion ( see point number one) initiating a stretch reflex in the tricep surae (gastroc/soleus) facilitating toe off through here and pushing you through the gait cycle, rather than pulling you through (with your hip extensors).
4. Likewise, the treadmill pulls the hip into extension and places a pull on the anterior hip musculature, especially the hip flexors including the rectus femoris, iliopsoas and iliacus. This causes a slow stretch of the muscle, activating the muscle spindles (Ia afferents) and causing a mm contraction (ie the stretch reflex). This acts to inhibit the posterior compartment of hip extensors through reciprocal inhibition, especially the glute max, making it difficult to fire them.
5. Because the deck is moving, the knee is brought into extension, with stretch of the hamstrings, the quads become reciprocally inhibited.
6. the moving deck forces you to flex the thigh forward for the next footstrike (ie footstance), firing the RF, IP and Iliacus, and reciprocally inhibit the g max
7. If your core isn’t engaged, the pull of the rectus femoris and iliopsoas/iliacus pulls the ilia and pelvis into extension (ie increases the lordosis) and you reciprocally inhibit the erectors and increase reliance on the multifidus and rotatores, which have short lever arms and are supposed to be more proprioceptive in function.
We are not saying they are bad and in fact, we tend to like self-propelled models more than motorized ones and agree with many of the points made. We are just saying that treadmills are not the same as walking on a flat surface and approximate but do not simulate actual gait.