Kinesio taping has no immediate effect on shoulder isometric scapation strength: A study of healthy participants

Abstract

BACKGROUND:

Shoulder function is directly related to scapular kinematics and the scapula has always been a part of shoulder rehabilitation. Kinesio Taping (KT) is a specific taping technique where flexible tapes indirectly stabilize underlying soft tissues to modify their behavior. KT has been utilized for scapular stabilization in shoulder rehabilitation but its effect on shoulder strength was not examined before.

OBJECTIVES:

The aim of this self-controlled therapeutic study was to assess the effect of KT on shoulder scapation (arm elevation in scapular plane) strength in healthy individuals.

METHODS:

This study was conducted on 160 shoulders of 80 healthy volunteers (34 males, 46 females; mean age: 23.8 [18–30]). The shoulder scaption strength was recorded, using an electronic dynamometer, as the maximal value of 3 consecutive measurements in two different forearm positions: ‘palm down’ and ‘empty can’. Two sets of measurements, 3 days apart, were taken. The results of untaped and taped measurements were compared. Scapular taping, dominant side, forearm position, sex, and body mass index (BMI) were analyzed.

RESULTS:

The test-retest findings of both forearm positions were highly correlated with ICCs ranging 0.978–0.990. There was no significant difference in strength between ‘without KT’ and ‘with KT’, 69.46 $\pm$ 26.94 N vs 70.33 $\pm$ 28.01 N, respectively ( $p=$ 0.126). In both experimental conditions, forearm position did not affect strength There was no significant difference between the results without and with Kinesio Taping in both forearm positions: $p=$ 0.458 (without), $p=$ 0.141 (with). Dominant side and male sex resulted in superior scores ( $p=$ 0.0001) while a positive correlation was calculated between BMI and shoulder strength ( $p=$ 0.0001, $r=$ 0.4).

CONCLUSIONS:

Based on our comparisons, scapular KT does not appear to influence scaption strength in healthy individuals.

1. Introduction

There is a strong association between scapular dysfunction and shoulder disorders. Thus, improving scapular stability has become an effective strategy in most rehabilitation protocols [1, 2, 3]. While supervised periscapular muscle training programs are the mainstay in most scapular stabilization protocols, lack of standardization, and sustainability are their major drawbacks.

Kinesio Taping (KT) is a specific taping technique where flexible tapes indirectly stabilize underlying soft tissues to modify their behavior [4]. This standardized and sustainable functional stabilization method has been proposed to improve scapular alignment [5].

We hypothesized that if KT improves scapular stabilization in healthy volunteers, this would positively affect shoulder scaption (abduction in scapular plane) strength which is a well-known outcome measure for the assessment of scapular stabilization [6]. The aim of this study was therefore to compare shoulder scaption strength of healthy volunteers before and after the application of KT.

2. Methods

2.1 Subjects

Eighty healthy volunteers (34 males, 46 females; mean age: 23.8 (range: 18–30) took part in this study. They were recruited following an institutional website announcement and informed about the test, while remaining blind to the study question. Before inclusion candidates were questioned and examined for a musculoskeletal or a systemic problem, which would interfere with the strength measurement. Those with previous shoulder surgery, trauma history in the last 3 months and shoulder or scapular asymmetry were excluded. Thus, the study was conducted on 160 shoulders of 80 healthy volunteers (34 males, 46 females; mean age: 23.8 [18–30]) who fulfilled the inclusion criteria. An institutional review board approval was obtained before the study (Koc University, Istanbul, Turkey; 2014.023.IRB2.010).

2.2 Procedure

Taping was performed by the same researcher, who was trained in the method prior to the study. Three tapes were used in each case: The first two from each acromioclavicular joint to the contralateral inferior angle of scapula, and a transverse tape through scapular spines. Subjects retained both scapulae in a retracted position during the taping procedure (Fig. 1).

Figure 1.

Measurement position: Standing with the arm in 90 ${}^{\circ }$ of abduction in the scapular plane (scaption) and the elbow extended. Volunteers were barefoot on a hard surface, feet adjacent. Two different forearm positions were used: Empty can and palm down.

Isometric scapation strength was recorded, using an electronic dynamometer (Mecmesin Myometer, West Sussex, UK) with a real time display. Measurement took place in standing with the arm in 90 ${}^{\circ }$ of abduction in the scapular plane and the elbow extended. The strap of the device was placed at the wrist while the measurements were repeated with the palm facing down (PD, palm down) and thumb pointing down (EC, empty can) (Fig. 2). Subject applied an upward isometric force for 5 seconds, 3 times consecutively, with 5 seconds intervals for rest in between each application of force. Subject then alternated the side and forearm position. During the measurements, loud verbal feedback was given while during the intervals the arm rested completely relaxed in the same position, supported by the examiner. The force applied during the test was monitored real time in Newtons. Maximum values were recorded for each of three consecutive measurements. Three days after the first measurement, scapular KT was applied, and the measurement was repeated. The results of untaped and taped measurements were compared. Together with scapular taping, dominant side, forearm position, sex, and body mass index (BMI) were analyzed for their effects on shoulder strength.

Figure 2.

Measurement position: Standing with the arm in 90 ${}^{\circ }$ of abduction in the scapular plane (scaption) and the elbow extended. Volunteers were barefoot on a hard surface, feet adjacent. Two different forearm positions were used: Empty can and palm down.

2.3 Data analysis

Statistical analyses were performed using IBM SPSS Statistics, Version 23.0 (IBM Corp, Armonk, NY, USA). In addition to descriptive statistical methods (average, standard deviation), paired and unpaired student’s $t$ -test and Pearson correlation test were used. Intraclass correlation was used to assess test reliability. The level of significance was set at $p<$ 0.05 An institutional review board approval was obtained before the study (Koc University, Istanbul, Turkey; 2014.023.IRB2.010).

3. Results

All 80 volunteers attended the second step of the measurement in the given period and completed the study. Average height, weight and body mass index (BMI) were 1.72 $\pm$ 0.1 m (female: 1.67 $\pm$ 0.1, male: 1.79 $\pm$ 0.1), 66.3 $\pm$ 12.9 kg (female: 59.9 $\pm$ 11.3, male: 74.9 $\pm$ 9.5) and 22.27 $\pm$ 3.27 (female: 21.53 $\pm$ , male: 23.29 $\pm$ 2.68) respectively. Intraclass correlation coefficient (ICC) and confidence intervals (CI) of all measurements were 0.982 (0.978–0.985) and 0.988 (0.987–0.990) in EC and PD positions, respectively and confirmed the reliability of the repeated measurements (Table 1).

Table 1

Intraclass correlation coefficients (ICC) and %95 confidence intervals of different measurements. Note that ICC is above 0.7 which is accepted as the minimum level for the reliability of a test

	Intraclass correlation	95% confidence
	coefficient	interval
EC, dominant	0.980	(0.974–0.985)
EC, non-dominant	0.985	(0.980–0.988)
PD, dominant	0.989	(0.986–0.992)
PD, non-dominant	0.988	(0.985–0.991)
EC, overall	0.982	(0.978–0.985)
PD, overall	0.988	(0.987–0.990)

EC: empty can; PD: palm down.

The mean scaption strength of the dominant side (71.73 $\pm$ 27.86 N) was significantly superior to non-dominant side (68.706 $\pm$ 26.98 N; $p<$ 0.001). No significant difference was observed between dominant and nondominant sides in EC positions and PD position without tape, in male volunteers. Remaining measurements were superior in the dominant side. The results of all the dominant and non-dominant side measurements are outlined in Table 2.

Table 2

Dominant and non-dominant measurement values of volunteers in both positions, with and without taping. Dominant side strength was superior to non-dominant side significant in all measurements ( $p<$ 0.05)

	Dominant		Non-dominant		$p$
EC, w/o taping
Male	88.92	$\pm$ 23.96 N	85.46	$\pm$ 23.2 N	0.066
Female	54.95	$\pm$ 14.18 N	50.61	$\pm$ 11.37 N	0.000
Total	69.39	$\pm$ 25.31 N	65.42	$\pm$ 24.48 N	0.000
PD, w/o taping
Male	98.89	$\pm$ 25.99 N	96.06	$\pm$ 22.87 N	0.133
Female	54.26	$\pm$ 10.8 N	50.38	$\pm$ 12.1 N	0.000
Total	73.23	$\pm$ 29.01 N	69.79	$\pm$ 28.6 N	0.000
EC, w/taping
Male	92.83	$\pm$ 25.33 N	87.72	$\pm$ 20.41 N	0.046
Female	53.18	$\pm$ 12.64 N	50.05	$\pm$ 11.91 N	0.001
Total	70.03	$\pm$ 27.35 N	66.06	$\pm$ 24.62 N	0.001
PD, w/taping
Male	101.91	$\pm$ 23.68 N	99.44	$\pm$ 22.94 N	0.188
Female	53.86	$\pm$ 11.91 N	49.89	$\pm$ 10.76 N	0.000
Total	74.28	$\pm$ 29.77 N	70.95	$\pm$ 29.89 N	0.000

EC: empty can; PD: palm down.

Table 3

Effects of taping on shoulder strength in two different positions and for both dominant and nondominant sides. There was no statistically significant difference ( $p>$ 0.05)

	w/o taping		w/taping		$p$
EC, dominant
Male	88.92	$\pm$ 23 N	92.83	$\pm$ 25.33	0.115
Female	54.95	$\pm$ 14.18 N	53.18	$\pm$ 12.64 N	0.219
Total	69.28	$\pm$ 25.27 N	69.72	$\pm$ 27.62 N	0.746
EC, non-dominant
Male	85.46	$\pm$ 23.2 N	87.72	$\pm$ 20.41 N	0.314
Female	50.61	$\pm$ 11.37 N	50.05	$\pm$ 11.91 N	0.542
Total	65.19	$\pm$ 24.52 N	65.98	$\pm$ 24.60 N	0.472
PD, dominant
Male	98.89	$\pm$ 25.99 N	101.91	$\pm$ 23.68 N	0.145
Female	54.26	$\pm$ 10.8 N	53.86	$\pm$ 11.91 N	0.671
Total	73.08	$\pm$ 29.14 N	74.27	$\pm$ 29.78 N	0.252
PD, non-dominant
Male	99.06	$\pm$ 22.87 N	99.44	$\pm$ 22.94 N	0.125
Female	50.38	$\pm$ 12.06 N	49.89	$\pm$ 10.76 N	0.623
Total	68.97	$\pm$ 29.22 N	70.86	$\pm$ 29.83 N	0.083

EC: empty can; PD: palm down.

The mean scaption strengths before and after KT were 67.41 $\pm$ 24.9 N and 68.04 $\pm$ 26.01 N, respectively, in EC position. The same measurements in PD position were recorded as 71.51 $\pm$ 28.77 and 72.61 $\pm$ 29.78 N. There was no significant difference between the results without and with KT in both forearm positions ( $p=$ 0.458 and $p=$ 0.141 for EC and PD, respectively), and in both genders (Table 3).

Both the male sex and the BMI showed positive correlation on maximum shoulder strength ( $p=$ 0.001, $r>$ 0.4). All measurements for male volunteers were significantly superior when compared to female volunteers ( $p<$ 0.05).

4. Discussion

Our hypothesis was based on the idea that Kinesio Taping would provide a sustainable and standard home-based modality for the rehabilitation of scapular disorders. For this purpose, we wondered whether the KT indirectly affects shoulder scaption strength, based on the widely accepted concept of a stabilized scapula enhancing shoulder function. Considering the beneficial results reported in different studies for various anatomic locations, it was expected that the Kinesio Taping would improve shoulder scaption strength immediately after application, in healthy subjects. However, the results of this research reject the proposed hypothesis. There was no statistical difference between measurements without and with taping, in both genders.

The measurement method used in this study was attributed to Constant et al.’s publications on his shoulder outcome score [7, 8]. There are still some controversies on the ideal measurement technique for shoulder strength. Although the standing position and 90 ${}^{\circ }$ of abduction in scapular plane (scaption) is considered the gold standard, there is lack of standardization regarding the measurement device. Handheld analogue dynamometers are widely used but they are of questionable value due to their low accuracy and unreliable results. For this reason, to improve the accuracy of the measurements, we utilized a table-fixed, electronic dynamometer.

Three consecutive measurements were performed to achieve the highest strength record. This technique was reliable as shown in our results with a high ICCs for both test positions. There are different recommendations in the literature regarding the forearm position [6, 9, 10, 11], and there is no consensus favoring one over the other, therefore we compared both techniques in order to substantiate a recommendation. However, the current results indicate that both forearm positions are reliable while the results are consistent with each other.

Although there is considerable number of studies regarding KT, its validity has not been sufficiently probed for any body part. In our method the obliquely positioned tape acted as the scapular reposition test (modified scapular retraction test) exerting a posterior tilt and external rotation effect, assisting in forward elevation and possibly improving shoulder strength [12, 13]. The transverse tape also assisted in supporting the retracted position of the scapula. We combined these two taping methods to achieve a stabilized scapula in a retracted position, and also to support and positively affect the upper body posture.

A significant positive effect of KT on muscle strength was suggested in several comparative studies. Hsu et al. on lower trapezius muscle [14], Vithoulka et al. [15] and Fu et al. on quadriceps [16], Lee et al. on flexor muscles of the hand [17] and Hagen et al. on back extensor muscles [18]. Hsu et al. and Slupik et al. also reported significant effects on muscle activity measurement with electromyography [14, 19]. Compared to the mentioned anatomical locations, the scapula and shoulder present a more complex musculature with a thicker subcutaneous tissue. However, Shaheen et al. managed to show scapular motion alterations with KT using a motion tracking system, suggesting that previously studied beneficial effects may also be valid for scapula and shoulder. Scapular taping increased the scapular external and upward rotations and posterior tilt in elevations in the sagittal plane [5]. Our results, do not support such an immediate stabilization effect and enhancement on shoulder strength.

This study is limited by the absence of scapular motion tracking, or another method to assess scapular stabilization. Furthermore, it is not possible to make a negative conclusion on KT’s overall role on shoulder rehabilitation, as the study assessed only the immediate effects.

Our study suggests therefore that scapular KT has no immediate effect on shoulder muscle strength. The long term utilization of KT has yet to be explored with different taping methods to prove its role in shoulder rehabilitation.