WHAT IS THE EFFECT OF SCAPULOTHORACIC TAPING ON MUSCLE ACTIVITY?

Based on the previous article, there appears to be an alteration of motor control in subjects with impingement. It is often proposed clinically that taping techniques can alter motor activity (1,2). However, the research surrounding the benefits of tape in this scenario is conflicting.

BY COLIN PATERSON, MCSP EXPERIMENTAL STUDIES T

he study by Cools et al (3) investigated the effect of taping over the upper trapezius

muscle as advocated by McConnell (4) (Figure 1). The aim of this technique is to inhibit the overactive upper fibres of trapezius and thus prevent excessive elevation of the scapula, which can occur in subjects with impingement. The results of their study found no beneficial effect of taping on motor recruitment patterns, the EMG patterns for all of trapezius and serratus anterior were unaltered. Contradicting these results are those by Morin et al (2) who found the same taping technique to decrease the activity in upper trapezius with a concurrent increase in the activity of lower trapezius. They did not assess the activity in serratus anterior in their study, limiting comparisons with other studies. Both Morin et al (2) and Cools et al (3) used a cross-over design with sound internal validity, although neither indicated the time frame between tape and no-tape sessions. Consequently, insufficient knowledge

is available about any potential carry-over after the tape session and the influence this could have on the results. The other difference between the two studies was the activity performed, which could explain the conflicting results. Cools et al (3) used flexion and abduction movements of the shoulder while Morin et al (2) utilised an isometric activity of 90º abduction and 45º internal rotation with elastic tubing. It is known that an isometric muscle contraction produces a more regular electromyographic reading and this would provide more consistent data to analyse, which again could be a factor explaining the differences between the two studies results (5, 6). Unfortunately, the use of pain free subjects without shoulder dysfunction severely limits the external validity of their results. It would appear they were trying to normalise the motor pattern of subjects with normal patterns already and therefore, the significance of their results or lack of, needs to be noted with caution.

The use of normal subjects was used in

ACTIVITY IN SERRATUS ANTERIOR MAY HAVE GREATER CLINICAL SIGNIFICANCE YET THIS HAS NOT BEEN ATTEMPTED IN LITERATURE

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IT WOULD APPEAR THAT TAPING TECHNIQUES TO ADDRESS THE REDUCED

the non-clinical study by Alexander et al (7). They utilised a taping technique proposed to facilitate the lower fibres of trapezius, shown in figure 2, and investigated its effect on motor neurone excitability. In line with other studies, the authors chose not to address a functional movement pattern or the effects on scapular positioning. Unexpectedly, the result of the technique was inhibition of the lower fibres of trapezius by an average of 22%. Clinically it is proposed that applying tape parallel to the line of muscle fibres facilitates muscle activity due to an improved length-tension relationship of the actin and myosin cross-bridges (1,4). Alexander et al (8) have further

investigated the issue of taping along and across the orientation of the muscle in relation to facilitating and inhibiting muscle activity respectively. They demonstrated that taping across the line of the muscle fibre failed to have any affect on motor neurone excitability (H-reflex) of gastrocnemius or soleus when taping the calf complex. However, when under tape and sports tape were applied along the line of the muscle fibres of medial and lateral gastrocnemius a resultant reduction in motor neurone excitability was measured. These results support the findings of their previous 2003 study (7). Their study did not directly attempt to explain why these results occur but they hypothesise that taping along the direction of the muscle fibres could shorten the muscle which in turn unloads the intrafusal

sportEX medicine 2008:36(Apr):18-20