PAIL’s and RAIL’s

Welcome back. In my previous post I spoke about the difference between Flexibility and Mobility- two different terms that are often used interchangeably. I also provided justification for the use of Controled Articular Rotations (CARS) as a means on improving mobility.

So how do you make improvements in mobility stick? The answer lays in the neuromuscular element of the mobility equation. Remember flexibility + strength (neuromuscular stimuli) = mobility. The brain needs to compute that the newly acquired active ROM is safe. This can be achieved by being dedicated in the quest for improved mobility- working on CAR’s daily for example, but also through isometric contractions. This is where PAIL’s and RAIL’s can come in useful.

Progressive Angular Isometric Loading and Regressive Angular Isometric Loading are protocols used to make improvements in mobility more permanent by targeting tissues on both sides of a joint. The IL’s highlights the neuromuscular or stretch input. Angular pertains to the angle created by tissues on both sides of a joint and Progressive and Regressive represent the same tissues on both sides of the joint and is determined by what you are trying to improve . Take the ankle joint as an example- When trying to improve Dorsiflexion, the progressive tissues would be the Gastrocnemius, Soleus, and Achilles Tendon. The regressive tissue would be the Tibialis Anterior.


Initially a passive stretch is held for 1-2 minutes. The focus here is on relaxtion and diaphramatic breathing (see my first post). After two minutes the PAIL’s contraction is initiated. Here you want to contract the progressive tissue statically with varying degrees of intensity- beginning with around 20% and working up to 80% (For beginners) and continue to hold for another 5-10 seconds. Once again you will need to remain as rigid as possible in adjacent areas- notably core. Following this, immediatly go into the RAIL’s contraction and hold this for 10-15 seconds. Following this first cycle you may have aquired some new ROM- so diaphramatically breath again and ease into the newly aquired ROM. Repeat as necessary.

Arrows denote isometric contractions of muscles that open the joint (green arrow, toes pressed into the floor) and the muscles that close the joint (red arrow, toes/ foot pulled upwards). Note- there will be no visible movement at the toes.

Active lift-offs

Active lift offs target end ranges of motion and can also help to make newly acquired ROM stick. I have found them to be particularly useful as specific warm-up drills also. Check out the video below from the Prehab guys for some lower body examples:

Neither PAIL’s and RAIL’s or active lift offs should elicit pain. Also don’t perform on an already injured area! Happy training!

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