As I believe that evidence based practice is a necessity in today’s performance enhancement world, I have decided that I will begin to more frequently review articles that I find relevant to our field.
Bellew, Frilot, Busch, Lamothe, and Ozane. “Facilitating activation of the peroneus longus: electromyographical analysis of exercises consistent with biomechanical function.” Journal of Strength and Conditioning Research 24.2 (2010): 442-46. Print.
The peroneus longus is the primary source of stability of the lateral ankle, and it is commonly misunderstood and inadequately trained due to its complexity. The peroneus longus originates on the posterio-lateral aspect of the fibula and takes a complex path to its insertion. First it passes posteriorly and inferiorly to the lateral maleolus, progressing posteriorly to the trochlear process of the lateral calcaneus, wrapping around the lateral aspect of the cuboid before being held into a grove on the plantar aspect of the cuboid with the help of the long plantar ligament.
In gait the peroneus longus serves to stabilize and transform the first ray of metarsals into a ridgid lever for propulsion, enhanced by the cuboid’s role as a pulley.
Many attempt to train the peroneus longus in an open-chain fashion, training solely the eversion function. Unfortunately, this is not consistent with the biomechanics of the PL and may be less effective. As a result the authors chose to evaluate the effectiveness of several biomechanically correct exercises.
To have a reference level of EMG activity for comparison, the authors chose to use a single leg heel raise as the reference test. Additionally, subjects performed a series of three exercises.
1. Quarter Heel Raise.
A heel raise performed with the first metatarsal atop a quarter for tactile feedback. As plantar flexion was performed, the subject was told to remain firm contact with the quarter.
2. Band Heel Raise
A band was placed around the midfood, and anchored laterally with a tension of 5 pounds. The subject then performed a heel raise while resisting the band’s pull of the foot into inversion/supination.
3. Open Chain Eversion
This exercise was done in sidelying on a table, with the feet hanging from the edge and a band anchored to the top foot with five pounds of tension. The subject then everted the foot fully and returned the starting position.
It was determined that the band heel raise resulted in 7.33% greater activation of the PL compared to reference. The QHR, while 4.18% less than reference, still resulted in 28.59% greater PL activity than eversion in open chain. Conventional eversion resulted in nearly 33% less EMG activity than a reference heel raise.
As lateral injury is quite common, and the PL is necessary for stability of the lateral ankle, training the muscle in a pattern that is biomechanically specific can offer better activation and potential gains in function. Additionally, as weak PL has been correlated with ankle inversion injuries along with sensory issues, the addition of such exercises may potentially enhance proprioceptive afferent activity and the subsequent motor response.
How can you use it in practice?
Lateral ankle injury is common in sport, and the resultant impacts on proximal and distal musculature can result in profound functional impairments. In rehabilitation of ankle injuries, these can be part of a program that includes various exercises to enhance mobility and stability in the right places. From a prevention standpoint, these exercises can be incorporated within the confines of a traditional strength and conditioning session. As it is a low level exercise, it may be wise to incorporate this type of exercise as “fillers” during rest breaks of bigger, upper body lifts.