A randomized crossover case control design was used to compare the effects of KT and conventional nonelastic silk tape (ST) on ankle muscles in subjects with chronic incomplete SCI. Patient selection was based on the clinical assessment, per the American Spinal Injury Association (ASIA) standards for neurological status, and on the degree of ankle spasticity, per the modified Ashworth scale (MAS). The inclusion criteria were chronic SCI lesion (i. e., at least 12 months post-injury), AIS level D, and MAS higher than 2 bilaterally in the soleus/gastrocnemius muscles. The exclusion criteria were the presence of other neurological or orthopedic impairments, participation in other studies, and pharmacological treatment for spasticity in the previous 4 weeks. This study was approved by the local ethics committee.

From January 1, 2013 to April 30, 2013, 33 consecutive patients who were admitted to the Spinal Cord Rehabilitation outpatient service of Santa Lucia Foundation were examined by an experience neurologist (Giorgio Scivoletto), of whom 11 subjects met the inclusion criteria. The demographics and clinical features of the SCI subjects are reported in Table 1.

After enrollment, SCI subjects were randomized into 2 treatment groups. Group A (n = 6) underwent 48 h of KT, followed by 48 h of ST 1 week later. Group B (n = 5) received 48 h of ST treatment, followed by 48 h of KT treatment after 1 week (Figure 1). All subjects underwent clinical and instrumental evaluations before (T0) and immediately after treatment (T_{48 h}). Electromyography (EMG) was performed only in Group B before, during, and after KT treatment. A certified KT practitioner (Federica Tamburella) administered all taping procedures. Clinical and instrumental outcomes were measured at T0 and T_{48 h} after removal of the KT by a different researcher (L.M.) who was blinded to the treatment.

KT and ST were applied bilaterally to the plantar-flexor ankle muscles, soleus (S), and gastrocnemius (G), per Luque-Suarez et al. (Luque-Suarez et al., 2014). Standard 5-cm single-strip nonelastic silk tape and Cure^© tape were used for the ST and KT, respectively. Y-strip tapes were applied to the S and G muscles with the subject in a prone position, the with knee extended and the ankle in 90° passive dorsiflexion. Both tapes were applied directly to the skin using a decompressive muscle technique, with 0% stretch, from the calcaneus to the medial and lateral femoral condyles (Figure 2). To maximize their adhesion, the tape strips were warmed by rubbing them in the hands several times on the application zone (Luque-Suarez et al., 2014).

All assessments were performed by the same examiner at the same time each day before application of the tape (T₀) and after 48 h (T_{48 h}) of KT or ST treatment. Neurological status was assessed using the American Spinal Injury Association (ASIA) and ASIA Impairment Scale (AIS) (American Spinal Injury Association, 2000). AIS levels A and B indicate complete motor lesions, and AIS levels C and D reflect incomplete motor lesions. Active and passive range of motion (ROM) was measured using a standard manual goniometer (Fong et al., 2011).

The Modified Ashworth Scale (MAS) (Gregson et al., 1999) was used to evaluate ankle spasticity. Spasms, clonus, and pain were scored using the Penn modified Spasm Frequency Scale (PSFS) (Penn, 1988), Spinal Cord Assessment Tool for Spastic Reflexes subscale for clonus assessment (SCATS) (Benz et al., 2005), and Global Pain Scale (GPS) (Wewers and Lowe, 1990), respectively. Balance and gait were assessed using the Berg Balance Scale (BBS) (Lemay and Nadeau, 2010), Walking Index for Spinal Cord Injury (WISCI) (Ditunno and Dittuno, 2001), 10-meter walk test (10WT) (Rossier and Wade, 2001), 6-min walking test (6MWT) (Poole-Wilson, 2000), and timed up and go test (TUG) (Podsiadlo and Richardson, 1991). Walking time tests were performed using a self-selected walking device, if needed (Patrick et al., 2011) and scored using the WISCI, as reported in Table 1. All subjects we subjected to instrument-based balance and gait analyses as detailed below.

The visual analog scale (VAS) was administered at T_{48 h} to assess perception of reductions in spasticity. Patients were asked to quantify the reduction in spasticity due to the tape, on a scale from 0 (no reduction in spasticity) to 10 (maximum reduction in spasticity). Electromyography (EMG) analyses were performed only for KT-treated subjects in Group B.

Stabilometric parameters were analyzed using a 320 × 75-cm (length × width) static force platform (Platform BPM 120, Physical Support Italia, Italy). The signals were amplified and acquired using dedicated software (Physical Gait Software Vv. 2.66, Physical Support Italia, Italy). Static stability was assessed per Tamburella et al. for chronic SCI subjects (Tamburella et al., 2013a). Patients stood barefoot in a natural and relaxed position with their arms by their sides, without shoes and with both heels lined up, under 2 sensory conditions: eyes open (OE) facing forward to a target 1.5 m away and eyes closed (CE). For each condition, the recording time was set to 51.2 s. and measurements were recorded 3 times and averaged.

We considered the following quantitative COP parameters:

- Length indicators: path length (L, mm), mean (V, L divided by trial duration), anteroposterior velocity (V_AP, mm/s) laterolateral velocity (V_LL, mm/s), and mean position of planar laterolateral COP.

Locomotion kinematic gait data were recorded and analyzed using the bidimensional KineView Motion System ® (Kineview, Hafnarfjordur, Iceland) per the protocol for chronic SCI subjects in Tamburella et al. (2013a,b), based on 3 strides at a self-determined velocity. Spatial movements of the lower extremity segments were monitored, based on the position of passive markers that were placed per the Helen Hayes biomechanical model (Kadaba et al., 1990). Kinematic data were reconstructed offline using Matlab (Mathworks, Inc., version 7.1, Natick, Massachusetts, USA).

The following kinematic data were considered: speed (m/s), cadence (N° step/min), stride length (STRIDE: mean of right and left stride in m), stance phase (STANCE: mean of right and left stance phase expressed as the percentage of gait cycle), and double-time support phase (DTS: mean of right and left double-time support phase, expressed as the percentage of gait cycle). STRIDE was defined as the event between 2 successive instances of foot-ground contact. STANCE was defined as the event from foot-ground contact to liftoff, and DTS was the time during which both feet were in contact with the ground (Huxham et al., 2006; Tamburella et al., 2013a,b). Foot-ground contact was determined manually from video recordings (Tamburella et al., 2013a,b). All gait variables were averaged from the kinematic data of the 3 trials.

For Group B patients, surface EMGs of tibialis anterior (TA), extensor hallucis longus (EHL), S, and G muscle activity were analyzed. Recordings were made before (T₀), 5 minutes after KT was applied (T₁), and after the KT was removed (T_{48 h}). EMG data were acquired through 4 wireless EMG sensors, 1 for each muscle, affixed per SENIAM recommendations (Oliveira et al., 2012) using EMG Delsys. EMG data were processed using EMG Works Analysis (Delsys, Boston, USA) using a pass-band filter between 10 and 450 Hz, and successively a 50-Hz notch filter. Root mean square (RMS) values, with a window of 0.250 and an overlap of 0.0625, were obtained from the filtered data. Data on each muscle were then imported into Matlab (Mathworks, Inc., version 7.1, Natick, Massachusetts, USA) to analyze muscle coactivation by calculating the coactivation index (CI) (Kellis et al., 2003).

CI is a relative measure of antagonist (S and G) contribution to total activation (S and G + TA and EHL) during the dorsiflexion task (Kellis et al., 2003). Thus, an increase in CI reflects a rise in co-contraction. CI ranged from 0 to 100%, with 100% indicating full muscle coactivation, defined as coactivation (i. e., simultaneous activity) of all ankle muscles. EMG data were recorded while patients were asked to perform maximal voluntary contraction (MVC) during 5 dorsiflexion active movements lying down with knees flexed and extended. Data were averaged across the 5 active tasks.

No participant withdrew from the trial, and all outcome measures were obtained for all SCI subjects. Descriptive statistics were generated for all variables. Prior to the statistical comparisons, normal distribution of the data was confirmed by Kolmogorov-Smirnov test.

Treatment effects were analyzed by grouping the KT and ST data on Group A and B subjects. Paired t-test was used to compare the effects of treatment, evaluated as T0 vs. T_{48 h}, for each KT or SK treatment groups. At T0 and T_{48 h}, KT and ST were compared by independent t-test and Mann-Whitney U-test for ordinal and nonordinal variables, respectively.

For each clinical and instrument-based parameter, the percentage of improvement due to KT and ST was calculated as follows:

Percentage of improvement = [(T_{48 h} data-T₀ data)/T₀]^*100. Treatment effects on percentage of improvement data were analyzed by independent t-test or Mann-Whitney U-test when appropriate.

CI data on KT-treated Group B patients were analyzed by repeated measures ANOVA, with time (T0 vs. T₁ vs. T_{48 h}) as the main within-group factor, followed by Bonferroni post-hoc test when the ANOVA results reached significance.

Statistical significance was considered at p < 0.05 (^*p < 0.05, ^**p < 0.005, ^***p < 0.001). All statistical tests were performed using the Statistical Package for the Social Sciences Software (SPSS), version 12.0 (Chicago, IL).

The clinical assessment results are shown in Table 2. As expected, almost no changes were observed between T₀ and T_{48 h} in the ST group. Conversely, vs. T₀, KT treatment at T_{48 h} significantly improved passive (p < 0.005) and active ROM (p < 0.001), SCATS score with the knees flexed and extended (p < 0.001), PSFS (p < 0.001), BBS (p < 0.001), and 6MWT (p < 0.001). Compared with ST, KT had significant treatment effects T_{48 h} on SCATS with the knees flexed and extended (p < 0.05) and on MAS (p < 0.05).

Based on percentage of improvement values, we noted significant treatment effects on active and passive dorsiflexion ROM (p < 0.001), pathological reflex with the knees flexed (p < 0.005) and extended (p < 0.001), PSFS (p < 0.001), GPN (p < 0.001), BBS, and 6MWT (p < 0.001).

With regard to perception of spasticity, VAS score was 7.9 ± 1.2 after KT and 2.5 ± 1.3 after ST (p < 0.05).

Between T0 and T_{48 h}, KT significantly improved L, C, V_LL, and V_AP under the OE and CE conditions (p < 0.05). Compared with ST, at T_{48 h}, KT had significant treatment effects on L, V, V_LL (p < 0.05), and V_AP (p < 0.001) under the OE condition and on L and V under the CE condition (p < 0.05). Based on percentage of improvement values, significantly treatment effects were pointed out for L, V, and V_AP (p < 0.05) under the OE and CE conditions and enhanced A, Y, and V_LL under the CE condition (A and V_LL: p < 0.05; Y and V_AP p < 0.005) (Table 3).

The effects of KT on STRIDE, STANCE, and DTS at T_{48 h} vs. T0 were significant (p < 0.001). Further STRIDE (p < 0.001), STANCE, and DTS (p < 0.005) improved with KT at T_{48 h} compared with ST. Comparison of percentage improvement values demonstrated significant treatment effects for all kinematic parameters (speed, cadence, and DTS: p < 0.05; STRIDE and STANCE: p < 0.001) (Table 4).

CI, as assessed with the knees flexed or extended, declined significantly immediately after application of KT (p < 0.001 − F [19.046]). After 48 h of treatment, this effect was maintained only with the knees flexed (p < 0.001 − F [0.820]) (Figure 3).

To determine the most notable effects of KT, the results were divided into primary and secondary outcome measures, as reported in Table 5. MAS, BBS, CoP V, 6MWT, STRIDE, and STANCE were identified as the most important outcomes, and the remaining data were considered secondary outcomes and used to evaluate additional effects of the intervention.

The sample size of SCI subjects (n = 11) was small, which might have limited the statistical relevance of the study. Nevertheless, the statistical differences were large, rendering the statistical error that was caused by sample size negligible. Further, as suggested by Friston (2012), significant results that are based on a small sample indicate a greater treatment effect than equivalent results in a large sample.

A follow-up study with a longer KT application is necessary to confirm these preliminary data, and a theory on the neurophysiological effects of taping would facilitate the generation of experimental hypotheses.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.