Updates from NASM’s research partners at the University of North Carolina at Chapel Hill
“It’s long been theorized that restricted ankle dorsiflexion could lead to greater knee valgus collapse,” says Darin Padua, PhD, ATC, professor and chair of the department of exercise and sport science at UNC-Chapel Hill. “We were interested in trying to verify whether or not that was the case.”
What the Studies Found
To do that, the researchers reviewed current literature and conducted studies of their own. One convincing bit of evidence: Working with study participants who exhibited excessive medial knee displacement (MKD), the researchers then simulated greater ankle dorsiflexion range of motion by placing a two-inch lift under the participants’ heels. The lift significantly reduced MKD. They then moved the lift to the forefoot as a way to further restrict ankle dorsiflexion. The results: a significant increase in MKD.
What This Means for Personal Trainers
If you identify knee valgus collapse in a client, add ankle dorsiflexion range of motion to the to-do list, as well as more traditional gluteus maximus, gluteus medius, and hip adductor activation. Padua and his team recommend a straightforward four-step approach.
1. Inhibit overactive muscles in the calf, particularly the gastrocnemius and soleus, through foam rolling. Pay special attention to any trigger points or tender nodules.
2. Use static stretching to take the ankle into more dorsiflexion range of motion.
3. Activate the muscles that are often weak or not activated sufficiently to prevent knee valgus motion. This likely means doing exercises to strengthen the gluteus medius and gluteus maximus, as well as strengthening muscles around the ankle like the posterior tibialis.
4. Perform functional movements that focus on movement quality. This means squats on two legs and single legs, progressing to more demanding exercises as necessary, but always focusing on proper movement over anything else.
“The sequence here really matters,” Padua says. “I often see people jump right into functional training, but that won’t provide as much benefit as approaching things in a more sequential manner.” He also notes that clients will start to notice a difference quickly, and you should be able to visibly spot improvements in movement patterns within three to four weeks.