Paper title: Assessing the differences in muscle stiffness measured with shear wave elastography and myotonometer during the menstrual cycle in young women Publication: Clinical Physiology and Functional Imaging Publication date: May 2022 INTRODUCTION One of the most important factors in maintaining dynamic knee stability is muscle stiffness, which is proportional to muscle fiber recruitment and... MORE
A ‘hands-on’ approach to axillary nerve injury
In today’s feature article, Chris Mallac explores the impact of axillary nerve injury. Damage to the axillary nerve occurs in athletes via a stretch from a fall or shoulder dislocation, compression, trauma, or as an unwelcome result of shoulder surgery. This peripheral nerve injury decreases both the strength around the shoulder, as the nerve innervates the deltoid and teres minor muscles, and the feeling at the shoulder, as it also provides cutaneous sensation to the regimental badge area. Movements effected by the injury include shoulder abduction and external rotation.
Mallac’s approach to rehab of the shoulder with an axillary nerve injury may be novel to some in the sports rehab field. He uses what’s often considered a traditionally neurological rehab technique: proprioceptive neuromuscular facilitation (PNF). However, his selection of this method fits right in since the injury is indeed neurological. Recruiting muscle contractions in specific movement patterns offers a ‘helper’ effect to the injured area (see figures 1 and 2).
Figure 1: D1 extension and flexion
Figure 2: D2 extension and flexion
These patterns of movement, though beneficial, are only part of the PNF protocol. In a climate of ‘hands off’ therapy, sports professionals may instruct athletes through these movements using resistance bands or free weights. By doing so, they may not be getting the full benefit of the technique. After all, PNF, by its very nature, requires proprioceptive input to provide the neuromuscular facilitation.
Spanish researchers wondered if using dumbbells in shoulder movement patterns was as effective as therapist led movements(1). They tested the muscle activation of 19 healthy individuals when performing PNF upper extremity D2 diagonal movement patterns with therapist-guided facilitation and with a dumbbell at an intensity of 75% of maximal effort (see figure 3).
Figure 3: PNF patterns performed with facilitation and with a dumbbell. (J Exerc Rehabil. 2018 Apr 26;14(2):219-225)
They measured more muscle activation when a therapist facilitated the movement. In addition, they found that the average time of co-contraction between the agonist and antagonist muscles increased with facilitated movement. This co-contraction works to increase stability around the shoulder joint.
Although PNF patterns are also effective at increasing range of motion, avoid further stress to the nerve in extremes of shoulder abduction and flexion. Using PNF during peripheral nerve recovery helps recruit the impacted muscles in functional movements that protect and stabilize the joint. Performing these movements using a PNF hands-on techniques appears to benefit the athlete more than when they perform the movements on their own.
- J Exerc Rehabil. 2018 Apr 26;14(2):219-225