Spinal stability exercises: evidence of preferential activation of internal oblique muscles in 3 and 2 point kneeling exercises

Abstract 

Rehabilitation of spinal stability muscles for the sportsperson with low back pain is common place in physical rehabilitation programmes with the aim of reducing re-occurrence of low back pain and improving function (O’Sullivan et al., 1997, Hides, Jull, & Richardson, 2001). Many exercise regimes are purported to activate the local spinal stability muscles (Beith, Synnott, & Newman, 2001) but there is little evidence regarding the actual muscle activation of these exercises and their progressions. The aim of this study was to identify the difference between muscle activation of 3 point and 2 point kneeling exercises. The muscles of interest were internal oblique and rectus abdominus.

Twenty healthy subjects (age 20.7 years SD 5.33)who all participated in sport, were recruited according to specific inclusion and exclusion criteria which included the ability to perform the abdominal hollowing manoeuvre (AHM) (Jull et al., 1993) SEMG was applied to internal obliques (IO) and rectus abdominus (RA). Maximum voluntary contractions were performed for normalisation of EMG data. Data was collected whilst performing the AHM followed by unilateral arm flexion (3 point kneeling) and then combined with contralateral leg/hip extension (2 point kneeling).

Results indicated in both 3 point and 2 point kneeling there was preferential activation of internal obliques compared to rectus abdominus, (mean IO 48.90, 56.13, RA 17.67, 19.28, microvolts, respectively) with a significant difference in activation of internal oblique only between 3 and 2 point kneeling. (). This is the first study to identify that progression of exercises from 3 point to 2 point kneeling preferentially activates internal obliques which are known to play a role in spinal stabilisation. This is key in rehabilitation of the sportsman who often has over riding global muscle activity.