I am not aware of any specific studies that have looked at each of the different products on the market, but I definitely have my reservations, especially about a whole class using the same device, as outlined below. There are three main reasons why I recommend avoiding foot stretchers:

1. The stretch is not specific to the point of restriction and may cause injury
2. Overly stretched ligaments can make the ankle very unstable
3. Most dancers have issues with strength and control, rather than range

Lack of specificity:

• My resistance to using any one device, especially across a whole class full of students, is that every foot is different and may require mobilising in different ways, as we will discover in this program. If you have stiff feet, the chances of one device being able to isolate where that particular foot needs more mobility is highly unlikely! Some feet need more range where the metatarsals meet the tarsal bones, others need it between the tarsal bones, some need it between the talus and the lower leg, and some need fascial releases much further up the line. Most of the bony restriction in ankle range that I see in the clinic is actually a block in the sub-talar joint, which cannot be stretched with any of these devices – most of them actually compress it!
• Most of the devices on the market focus on forcing the foot into a pointed position, and this can result in compression of the structures at the back of the ankle. Many students with restricted range have issues with pain in the back of the ankle anyway, due to constantly working against restriction, so forcefully over-pointing the foot can actually exacerbate compression in the back of the ankle, often leading to posterior impingement.
• If there is to be any benefit from using a foot stretcher, the stretch should be felt as a gentle stretch spread over a wide area on the front of the foot. It should never be felt as pain, cramping in the foot, pain or compression in the back of the ankle, or as a focused stretch at one point.

Increased laxity in the ligaments:

• Most foot stretchers are promoted by suggesting they help stretch your ligaments in order to allow a fully pointed foot.
• Over stretched ligaments have reduced proprioceptive feedback, meaning that it is harder for you to feel where the foot is, making the foot more unstable. We definitely do not want to do this, especially when when progressing with pointe work.
• Please also notice that in just about all of the images you see advertising foot stretchers, the dancer also has a slightly (or not so slightly) hyperextended knee. These girls most likely already had a lovely line, and didn't need much assistance from the device to make it look beautiful. If you already have hyper-mobile feet – strong stretches across the front of the foot may overstretch the ligaments, making the foot even more unstable and vulnerable to injury.

The issue of strength

• Any attempts to increase the range of motion into either a pointed or flexed position must be accompanied by specific strengthening exercises so that you can actually use the new range of motion when you dance.
• Excessive range in the ankle without excellent proprioception and strength can be the cause of many foot and ankle injuries.
• It is also important that you build this strength as your range increases. Sudden increases in mobility, without the appropriate awareness and strength, can make you much more likely to injure or foot in class.