The Science of Between-Round Recovery With The Passive Leg Raise

Resident physician David Liang, based in the United States who specializes in Physical Medicine and Rehabilitation (PM&R) gives us his perspective on between-round recovery with the passive leg raise after Alexey Oleynik’s use of this in last weekend’s UFC Fight Night 174.

Oleynik is arguably one of the most interesting fighters in the UFC. 43 years old. 74 fights. Fighting professionally since 1997! It's as if he sustains himself on the life force of the younger fighters he strangles, like an MMA Dracula.

Although “The Beast” Derrick Lewis ultimately proved to be too beastly in their bout, Oleynik did show something interesting during the fight. Between rounds he rested while laying flat on his back with his legs propped up against the cage. Aside from looking comfortable, is there any science behind this madness? Let's take a look.

This position is called a passive leg raise in the medical world, and it's used in the hospital setting to determine if patients would be responsive to IV fluids should their blood pressure drop.

With the assistance of gravity, blood will be more effectively returned from the legs back to the right atrium of the heart. This inflow of blood will stretch the chambers of the heart, leading to an increase in the stroke volume (volume of blood the heart is able to pump out with each beat). Obviously the greater the stroke volume, the more efficiently blood and oxygen will then be delivered to the rest of the body.

Heart rate is also decreased during this position, as alluded to by Paul Felder during the event broadcast. But this appears to be a secondary effect, a type of compensatory response to the main action of increasing the stroke volume.

These hemodynamic changes tend to occur within the first 30 to 90 seconds of holding this position. Perfect for a rest in between rounds.

A Japanese study found that any leg raise angle between 20-40 degrees would have the intended effects. However, an angle of 20 degrees was found to best lower heart rate in particular. So, the legs need not be as high up on the cage as Alexei had them. But hey, he certainly has the experience to know what works for him.