The effects of Dynamic® taping on vertical jumps in adolescent volleyball players with low medial longitudinal arch: a cross sectional study


 Background: Taping is one of the conservative intervention methods used by health professionals for a long time to provide mechanical support for the musculoskeletal system. However, there is insufficient evidence to demonstrate its effect on Dynamic® taping. The purpose of this study to investigate how Dynamic® taping affected vertical jump and medial longitudinal arch (MLA) height in adolescent volleyball players with a low MLA. Methods: In the study, 23 female athletes participated with the mean age of 15.22±1.54 years. On the first day, athletes who were evaluated without a tape and they received Dynamic® taping the next day. Then they were re-evaluated with the taping on. All athletes jumped on eight different surfaces, first with shoes and then barefoot (without shoes). The distance of navicular drop was evaluated with the navicular drop test and vertical jump height was measured with the device VERT® (Mayfonk Athletic, USA). For the statistical analysis, the software SPSS version 22.0 for IBM (SPSS Inc., Chicago, Il, USA) and dependent groups student’s t-test was used. P-value accepted as 0.05 and cases where P < .05 were considered statistically significant. Results: The distance of navicular drop both in the right and left feet decreased in a statistically significant (P < .05) extent following Dynamic® taping. Comparing the vertical jump heights on eight different types of floor surface, before and after taping, with and without shoes, it was found that there was no statistically significant difference for all cases (P > .05). Conclusions: This was the first study to investigate the effectsg of Dynamic® taping on vertical jump and MLA height in adolescent volleyball players with low MLA height. As a result of the study, it was found that Dynamic® taping did not have a statistically significant effect on the vertical jump height, but it decreased navicular drop distance at statistically significant levels. Dynamic® tape application can be used as an easy-to-apply practical treatment agent to support the MLA in asymptomatic adolescent athletes with an increasing navicular drop. Trial registration: Before starting the study, approval from Gazi University Ethics Commission dated 20/11/2018 and numbered 14574941-050.99- 153747 was obtained.


Background
Volleyball is a highly dynamic sport branch drawing fans from all age groups, but from among young people in particular, since its early beginnings. It involves short and explosive motion patterns that require speed and agility, and various jump positions that may vary depending on the player's position in the game. Jumping is one of the common motor skills in various branches of sport and is among the basic criteria for physical performance. [1][2][3][4] In a game of volleyball, players often jump repeatedly in vertical and horizontal directions. 5 It is shown that players with higher game performance have higher vertical jump (VJ) values. 6 The higher a player can jump in the vertical direction, the better is their performance in spike shots and block. For a jump serve, a volleyball player needs to meet the ball at the highest point possible for an effective shot. Similarly, if the player wants to prevent an opponent attack through a block jump and attack with a spike shot, they need to jump up to the highest possible point again. In conclusion, to exert superiority over the opponents and contribute their team's success in a game, a volleyball player needs well-developed jumping skills. 5 Therefore, it is important to invest in jumping skills for a volleyball player from an early age to make sure they can maintain their career in volleyball with a good jumping performance.
A relationship was shown between medial longitudinal arch (MLA) posture and lower extremity injuries, even though its reason could not be fully explained. The decrease in MLA height causes losses in optimal foot function, lower extremity injuries such as plantar fasciitis and patellar tendinitis, and waist problems. 7 Furthermore, previous studies also showed that the decrease in arch height increased the risk of lower extremity injuries related to excessive use, including patellofemoral pain syndrome and medial tibial stress syndrome, as well as having a negative effect on the jumping performance. 8 Therefore, low MLA structure in athletes should be considered as a condition requiring intervention.
Taping, a method popular straight from its rst launch, is one of the conservative intervention methods used by health professionals for a long time to provide mechanical support for the musculoskeletal system. It is generally used to prevent sports injuries and, failing that, to rehabilitate athletes during their comeback following an injury. There is a variety of taping methods used for this purpose: they can be implemented with exible tapes (Kinesio® tape, Dynamic® tape) or with in exible ones (rigid tapes). 9,10,11,12 The decrease in MLA height is often accompanied by excessive foot pronation. 13 Literature contains studies showing that MLA supportive anti-pronation taping techniques provide temporary external support of MLA increasing navicular height and that it is a good temporary treatment method for athletes with injuries and/or pain due to low MLA. In these studies, taping prevented drop of the arch by helping maintain the MLA height as the foot carries its own weight. Moreover, taping had a positive effect on the extent of navicular drop (ND) as it temporarily increased MLA height. 13,14 Dynamic® tapes contain high-grade elastic latex, enabling them to stretch both longitudinally and transversely. Thanks to this feature they have a high traction torque. With its ability to imitate movement without restricting it, Dynamic® tape nds a use as a biomechanical device to support body structures. 10 The eld literature contains studies on how different taping techniques (Kinesio® taping, rigid taping, and the like) used to support MLA on VJ affect performance. 15 However, it is found that as far as athletes with low MLA are concerned, there is a want of studies on the effects of Dynamic® taping (DT) to support MLA on vertical jumping performance. The fact that DT is now a popular technique frequently used by athletes is cause for recent attention to a need for scienti c research with a view to producing more objective and evidence-based results on the subject. In light of the aforementioned, the aim of this study was de ned as to examine the effects of DT on vertical jump height and MLA height in adolescent volleyball players with a low MLA height.

Methods
This study, in which the effect of DT on vertical jumping with the aim of changing the MLA height was investigated, was designed as a single group study. Participants were invited to two identical test sessions. On the rst day, athletes who were evaluated without a tape and they received DT the next day.
Then they were re-evaluated with the taping on. The sessions consisted of tests that measuring VJ height and ND distance (dependent variables). All athletes jumped on eight different surfaces, rst with shoes and then barefoot (without shoes). Before starting the study, approval from Gazi University Ethics Commission dated 20/11/2018 and numbered 14574941-050.99-153747 was obtained. Furthermore, informed consent forms were submitted to the athletes and their families to the effect that they were participating voluntarily and required signatures were obtained. Sample size was determined according to the sample analysis with G*Power 3.1 software. As for the effect size, it was calculated as 1.001 following a the study in the eld literature by Nakajima and Baldridge 15 . In order to exceed 95% in determining the strength of the study, 13 people were needed at a signi cance level of 5% and an effect size of 1.001 (df = 11.414, t = 1.790).

Participants
In the study, 23 volunteer and asymptomatic adolescent female volleyball players participated with the age (mean ± ss) = 15.22 ± 1.54 years and BMI (mean ± ss) = 19.66 ± 1.74 kg/m²; all were engaged in the same sports club and admitted in the same training program. The study included athletes between ages 12 to 19, with a ND of 8 mm and more, and no history of injury to the lower extremity in the past 6 months or no history of surgical operation on the lower extremity at all. Athletes who described lower back pain or exercise-induced pain, had acute orthopedic or systemic discomfort during the measurements, or were allergic to tape material were excluded from the study.

Procedures
All evaluations were performed in the same facility, during the morning hours. Demographic information of the athletes was recorded on the evaluation form prepared by the researchers. After this, athletes were randomly invited to take the ND and vertical jumping tests. Taping was not used on the rst day of evaluation. Athletes who were invited for re-evaluation at the same time the next day rst received DT before the evaluations started. The average delay before the start for adaptation to the tape was 20 minutes. Then the same evaluation procedure was repeated with all athletes. Navicular Drop Test. The navicular drop test was used to evaluate the height of the MLA (Fig. 1). For the test, athletes were seated in a chair with feet bare and subtalar joints in neutral position. Using a card lain on the oor and a pen, both feet were demarcated at the level of the navicular tubercle. The same procedure was then repeated in the standing position, rst with full body weight on one foot, then with both feet bearing equal weight. All demarcation for one athlete was done on the same card. The distances between the points marked on the card were measured with a tape and recorded in mm as the extent of ND. 16 Vertical Jump Test. VJ heights of volleyball players were evaluated with VERT® (Mayfonk Athletic, Florida, USA), a device of proven reliability and validity. 17− 19 All athletes jumped rst with, then without shoes on a total of 8 different oors: tara ex, concrete, parquet, grass, soil, arti cial grass, sand, and tartan (Fig. 2). Before starting the test, athletes were warmed up with stretching exercises. On each surface, 3 maximum jumps were performed. After obtaining the measurement with shoes on the same oor, a 3-minute break was taken. Then, measurements were repeated barefoot on the same oor. Each time there was a 5-minute break before moving on to the next oor surface. The average of 3 maximum jumps was recorded. 17 Dynamic® Taping. Taping was performed by a certi ed physiotherapist with original Dynamic® tape, 5 cm wide. Arch support technique was used as a taping method. For the taping procedure, the athletes were required to sit steadily in a reclining position with feet and ankles free in space and ankles at plantar exion and inversion, forefoot at adduction, and hallux at exion. The tape was applied as one piece in an 'I' shape on hairless skin already cleaned with alcohol. Taping began from the plantar surface of the hallux proximal phalanx with zero tension in the rst anchor section with a width of 3 or 4 toes. Then the tape was stretched towards the mediolateral calcaneus of the sole and wrapped around the posterior of the calcaneus, from which extended obliquely onward to include the navicular tubercle from the lateral to the mid-plantar section of the foot. Finally, zero tension was applied on the anchor section of 3-or 4-toe width in the dorsum of the foot, towards the distal part of the ankle (Fig. 3). Maximum tension was applied on the tape as it crossed the navicular tubercle. 10

Statistical Analyses
For the statistical analysis of the data, the software SPSS version 22.0 for IBM (SPSS Inc., Chicago, Il, USA) was used. The suitability of variables for normal distribution was examined by visual (histogram and probability graphs) and analytical (Kolmogorov-Smirnov/Shapiro-Wilk tests) methods. Descriptive statistics of the data with normal distribution were presented as mean ± standard deviation (SD), with Pvalue accepted as 0.05 and cases where P < .05 were considered statistically signi cant. Dependent groups Student's t-test was used to analyze the data from the measurement results obtained before and after taping and also to compare mean values.

Results
A statistically signi cant difference was found in the ND distances before and after taping (P < .05), with the extent of ND reduced signi cantly after taping in both right and left feet (Table 1). The vertical jump test was performed on eight different oor surfaces, with and without shoes on, and before and after taping. Table 2 shows the test results. There was no statistically signi cant difference in the VJ height based on any of the parameters above (P > .05).

Discussion
This was the rst study to investigate the effects of DT on VJ and MLA height in adolescent volleyball players with low MLA height. As a result of this study, it was observed that DT signi cantly reduced the ND distance, but did not have any signi cant effect on a functional parameter such as the VJ height.
Low MLA structure is implicated as a factor in lower extremity injuries in athletes due to overuse, together with excessive foot pronation. 20 Taping is one of the conservative treatment options used to control increased pronation. Many studies investigating the acute effect of anti-pronation taping methods on MLA showed its positive effect on the distance of ND. 21,22,14 One study with elite athletes found that rigid taping was more effective than Kinesio® taping in increasing navicular height. This nding was associated with the fact that rigid tapes had no stretching margin. 23 In our study, we observed that the ND distance after DT decreased by the statistically signi cant extent of 1.7 mm in both feet. This nding was consistent with previous studies supporting the literature and might be due to the strong support the Dynamic® tape provides to the MLA, which tends to atten under the weight of the foot to retract towards the high arch position. The main aspect of this study that differs from previous ones was the use of Dynamic® tapes as taping material. They are more rigid than Kinesio® tapes, albeit still exible. Despite previous study results to suggest that rigid tapes were to be used most frequently in individuals with a low MLA and the ND distance could be reduced best with a rigid tape, these tapes limit movement to a certain extent because of their in exibility. Kinesio® tapes, on the other hand, were found to have some restrictive effect on soft tissue without limiting active movement, but the number of studies with Kinesio® tapes is insu cient to have evidential value. 10 Consequently, the Dynamic® tape is considered to be advantageous over the other types with its ability to easily stretch in four directions without restricting voluntary movement, while providing biomechanical support to the tissues involved.
Volleyball is a sport that can be performed on different surfaces including sand, grass, wood/parquet, etc.
In a study with 15 beach volleyball players, Bishop 24 compared the heights of 4 different types of VJ on the wooden oor and sand and reported higher vertical jumps on the wooden oor in all types of jumps.
In another study Giatsis et al. 25 compared the VJ height of volleyball players on sand and wood surfaces and found lower vertical jumps on the sand as compared to wooden oor, resulting in an increase of the friction coe cient between the foot and the ground, due to the fact that sand was mobile oor. In similar studies with elite adolescent volleyball players, it was reported that a mobile oor surface structure such as sand negatively affected jumping performance and associated this nding with the greater decrease in fatigue-related lower limb muscle activation on a mobile ground. 26 In our study, after the taping procedure, no signi cant difference was found between VJ height values of the volleyball players either with or without shoes on or on the basis of oor type, namely, the eight different oor surfaces used: tara ex, concrete, parquet, grass, soil, arti cial grass, sand, and tartan. Although the measurement results were not statistically signi cant, the biggest increase in the VJ height after taping was obtained on parquet oor with shoes on and on tartan surface without shoes. Furthermore, VJ height on sand turned out to be relatively low compared to other oor surfaces. The results of this study were consistent with previous study results. Based on these results, it is possible to argue that a fragmented and mobile surface structure such as sand may have an adverse effect on the jumping performance by causing resistance against athlete's foot movements. The relatively higher vertical jumps recorded on parquet and tartan oors as compared to grass can be associated with a weaker shoe grip (amount of friction) on the parquet and tartan than on grass. Reduced amount of friction might be responsible for smaller resistance in the beginning of an active movement, enabling the athlete to jump higher.
Taping is a method frequently used among athletes to prevent injuries and improve performance components such as jumping function. As a sub-parameter of jumping performance, VJ is considered as a widely used assessment criterion in many sports about an athlete's lower limb strength and neuromuscular fatigue. 18 The limitations of this study can be listed as follows; rst, asymptomatic female athletes with no history of injury were evaluated. There is a need for future studies examining the effects of taping on symptomatic disorders. Secondly, participants were evaluated within approximately 20-25 minutes after taping. This period was perhaps su cient to reveal the possible effects, but studies to determine the long-term effects of taping are needed to obtain more precise information. Finally, there was no study found in the literature that scienti cally demonstrates whether Dynamic® taping has an effect on vertical jumping performance. Further studies are needed to clarify the clinical signi cance of our study ndings.

Conclusions
This was the rst study to investigate the effects of DT on VJ and MLA height in adolescent volleyball players with low MLA height. As a result of the study, it was found that DT did not have a statistically signi cant effect on the vertical jump height, but it decreased ND distance at statistically signi cant levels. It is our conviction that the study is unique and original in this respect and may lead the way to future studies with valuable scienti c contributions. DT is a practical and effective method of intervention in asymptomatic athletes under the risk of increased ND. As a result, DT can now be used in athletes to support the medial longitudinal arch.

Declarations
Ethics approval and consent to participate Before starting the study, approval from Gazi University Ethics Commission dated 20/11/2018 and numbered 14574941-050.99-153747 was obtained.

Consent for publication
Informed consent forms were submitted to the athletes and their families to the effect that they were participating voluntarily and required signatures were obtained.

Availability of data and materials
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.  Dynamic® tape application