Static Stretching of the Soleus and Gastrocnemius muscles
(Diagrams in attachment)
As Carl has pointed out in the past, maintenance of the medial longitudinal arch (MLA) is crucial when performing stretches for ankle range of motion. In conventional standing stretches, the foot is flat to the floor and the subject steps forward to achieve dorsiflexion of the rear ankle. This can result in a great deal of force being applied as the weight of the body is ahead of the foot while the gastroc and soleus muscles are in a weak position, leading to easy loss of MLA height and foot/ankle posture, and the same can be said for knee to wall stretches where the weight is going forward aggressively.
One solution I recommend is the use of a stretching wedge to achieve dorsiflexion without as much strain due to gravity. I like the use of relatively long duration stretches for the gastroc and soleus, but the reality is that for most concentration is difficult to maintain in static stretching due to the static and seemingly mindless nature of the task. This is a big problem as lack of concentration can lead to loss of technique (in this case MLA height) and long duration stretching of ligaments which is not desirable.
I must give credit to a trial involving patients with posterior tibial tendinopathy from Kornelia Kulig et al ( https://ptjournal.apta.org/content/89/1/26.full ) for highlighting this idea to me. While the subjects in the trial will possess much greater anterior and central weight distribution than athletic populations, resulting in a greater effect of gravity, I think the idea is quite valid. The figure from trial is this one:
I prefer to see the free leg stand lateral to or slightly behind the wedge for soleus stretching to increase precision through decreasing gravitational issues (it is easy apply enough force to get a stretch), and so the tracking of the knee over the foot can be visually monitored. The gradient of the wedge should be appropriate to the level of mobility.
A FAQ is whether calf stretching with heel off a step is equivalent to the wedge, and the answer is no as overall foot posture and orientation of the plantar fascia enhances posture and neural quailties with a full foot contact on a wedge. The MTP will hyperextend with the MTP as a fulcrum for the stretch (see file attached to post). Additionally we are leaving gravity to drop the heel, control the movement and alter MLA height. MTP kinematics is crucial in sprinting and I prefer to control their movement closely rather than be at the mercy of gravity.
Initial tests: Manual testing of dorsiflexion with sub talar joint stabilized by a therapist, and knee to wall tests (goniometry or cm) with very strict control of MLA height can guide starting position and inclination of wedge/slant board. Soleus in particular is very Type I dominant, and long-duration low intensity work can be useful.
Tibialis posterior is a strong inverter. Due to this and other factors, turning the foot out is not advised for triceps surae stretching and Kulig choses a straight leg posture and knee to wall tests call for a straight alignment of heel to toe and tracking of the knee straight ahead.
Control vs Gravity: A wedge/slant board is advised for support of both the MTP and ankle joints, and a change in moment of inertia of the tibia as well as the rest of the body. A stance with the resting leg behind the wedge should be used initially to allow knee tracking to be monitored. As range and technique improves moving toward the front may be possible.
Key compensations: Loss of MLA height, knee tracking too far laterally or medially with reference to the foot.
Cues: Tall arch, tall hip, open hip, open ankle, straight heel-toe.
Sequencing: I generally prefer to perform triceps surae stretching last as many ground based stretches push the ankle into undesirable positions (though changing these positions as per below can help). Soleus is an important postural muscle with high Type I content so long duration stretches are indicated and changes to day to day postures e.g. arch height during sitting and introduction of orthoses/heel lifts can be important.