Vilas-Boas, Machado, Kim, Veloso (eds.) Portuguese Journal of Sport Sciences Biomechanics in Sports 29 11 (Suppl. 2), 2011

There are substantial differences in the manufacturing processes of the different kinds of A COMPARISON OF PLANTAR PRESSURES BETWEEN TWO DIFFERENT intra-oral devices, where the MOM intends to respect the correct physiologic jaw relationship, PLAYING SURFACES IN TENNIS and the correct alignment of the teeth occlusion, Fig 3-C, which is not valid for the BBM, Fig 3-D. Michael Eckl, Philipp Kornfeind and Arnold Baca

A B C Department of Biomechanics, Kinesiology and Applied Computer Science, ZSU, University of Vienna, Vienna, Austria

The purpose of this study was to compare two different playing surfaces in tennis – clay vs hard-court (OptiCourt) – in order get more insight on the influence of the effect of surface on load. Eight male tennis players performed two types of tennis specific motions. Inside plantar pressure was measured for the right foot during these movements. Higher maximum forces could be observed for the OptiCourt for the baseline D play. In more detail, maximum force, peak and mean pressure were higher for the heel region on the hard-court. Higher values were found on clay for the hallux and lesser toe Figure 3: A) T-Scan® data of MOM were we can analyse the centre of foces howing equilibrium region. These results are in agreement with those of previous studies as they give of contacts throuhgout the entire mouthguard, B) T-Scan® data BBM, C) MOM, D) BBM evidence that playing surface affects loading in tennis.

CONCLUSION: Sports-related oro-facial trauma can be reduced or avoided by the use of a KEY WORDS: tennis court, insole pressure, injury. properly fitted mouthguard. Dentists play the key role in the prevention and treatment of sports-related dental and oro-facial injuries as well as promoting the research on the INTRODUCTION: Artificial playing surfaces are widely used in a variety of sports. The preventive procedures with a multidisciplinary team including mechanical engineering. properties of these surfaces not only influence performance, but also affect injury rates The manufacturing procedures of the MOM can be more complicated and time consuming, (Dragoo & Braun, 2010; Girard, et al., 2007). In tennis, the results of several studies indicate but it will be proportional to its higher level of protection, due to its occlusal stability, muscular that clay is significantly safer than grass or hard-court surfaces. Respective conclusions stability and protection of the TMJs. The MOM is indispensable in reducing the impact force should, however, be considered with caution (Dragoo & Braun, 2010), as the characteristics and may be a further contribute to the establishment of guidelines for safer mouthguards. of the playing surface cannot be taken isolated when assessing injury risk. Girard et al. Educational programs, like symposiums, seminars with athletes, parents, coaches, medical (2007) and Girard, Micallef and Millet (2010) have compared plantar pressures between clay staff, should be implemented to encourage and educate the sports community regarding the and Greenset in order to assess loading. They concluded that foot loading is affected by risks of oral injury in sports, and the importance of fabricating properly fitted intra-oral playing surface during tennis activities. Moreover, they inferred from their analysis results devices, like MOM, regarding their protective properties, costs and benefits. that Greenset induced higher loading in the hallux and lesser toes areas but lower relative load on the midfoot than clay (Girard et al., 2007). REFERENCES: In the present study, plantar pressures between OptiCourt and clay have been compared. ADA Council on access, prevention and inter professional relations and ADA council on scientific OptiCourt is a specific type of hard-court surface, which has been used during the last years affairs. (2006) Using mouthguards to reduce the incidence and severity of sports-related oral injuries. in the ATP-tournaments in Vienna, Austria. It was of interest, if a comparison of clay to Journal of American Dental Association.137;1712-1720. another hard-court surface (OptiCourt uses fixed silica sand for the top layer) resulted in Biasca N, Wirth S, Tegner Y. (2002). The avoidability of head and neck injuries in ice hockey: an analogous findings to those from the study by Girard et al. (2007). historical review. British Journal of Sports Medicine. 36 (6): 410-27. Maeda Y, Machi H and Tsugawa T. (2006). Influences of palatal side design and finishing on the METHODS: Eight right handed male tennis players of similar playing style (age: 22 ± 2.6 wearability and retention of mouthguards. British Journal of Sports Medicine. 40: 1006-1008. years; body mass: 65 ± 3.2 kg; height: 1.73 ± 0.05 m) with an International Tennis Number of Patrick D. G., van Noort R. and Found M. S. (2005). Scale of protection and the various types of 6 or better participated in the study. None of the subjects was restrained by injury or fatigue. sports mouthguard. British Journal of Sports Medicine. 39: 278-281. Two different tennis specific movements were performed with own shoes (seven players: all- Takeda T, Ishigami K, Handa J, Naitoh K, Kurokawa K, Shibusawa M, Nakajima K, Kawamura S. court; one player: clay, also for hard-court use) on the two playing surfaces, a baseline play (2006). Does hard insertion and space improve shock absorption ability of mouthguard? Dental comprising eight shuttle runs as described by Girard et al. (2007) and a sequence of Traumatology; 22: 77–82. forehand strokes. Within this sequence players had to try to reach and return ten tennis-balls Takeda T, Ishigami K, Kawamura S, Nakajima K, Shimada A, Sumii T, Swain M. (2006). Adhesive following one after the other, which were thrown at a defined speed from a ball machine. strength and its improvement referring to the laminated-type mouthguard. Dental Traumatology. 22: Players stood in the middle of the court behind the baseline. Balls were thrown diagonally 205 from the opposite side of the court into the right half of the court of the player’s side and Tran DC, Cooke MS, Newsome PR. (2001). Laboratory evaluation of moutguard material. Dental bounced about three metres before the baseline and one metre to the side line. Players Traumatology. 17(6):260-5. started when the ball left the ball machine. After every attempt to reach and possibly return Westerman B, Stringfellow PM, Eccleston JA. (2002). EVA mouthguards: how thick should they be? the ball they had to go back to their starting position. Measurement started with the first step Dental Traumatology. 18: 24–27. heading to the first ball thrown out of the ball machine and ended with the last step after reaching/returning the tenth ball. The players were instructed to hit the ball as good as Acknowledgement possible. It therefore appears not to be of much relevance, if the return was successful or This research was sponsored by FCT-Fundação para a Ciência e a Tecnologia, under the project not. PTDC/EEA-ACR/75454/2006.

ISBS 2011 601 Porto, Portugal Vilas-Boas, Machado, Kim, Veloso (eds.) Portuguese Journal of Sport Sciences Biomechanics in Sports 29 11 (Suppl. 2), 2011

After warming up the players performed two trials to get accustomed to the conditions of the Table 2 baseline play. A third trial was used for data recording and evaluation. The measurement of Plantar pressure parameters for the heel the forehand sequence was preceded by five forehand strokes, which were not evaluated. Baseline play Forehand play Inside plantar pressure was recorded using the X-Pedar insole (Novel GmbH, Munich, OptiCourt Clay OptiCourt Clay Germany). The insole was placed between the foot and the plantar surface of the right shoe. Maximum force (N) 702 (77) 464 (30) * 645 (70) 532 (65) The following parameters were determined for the whole foot and for four defined regions Peak pressure (kPa) 329 ( 46) 218 (26) * 298 (45) 238 (21) * (heel, midfoot, forefoot, hallux and lesser toes; see Figure 1): Maximum force, peak Mean pressure (kPa) 21 2 ( 23) 140 (9) * 195 (21) 161 (20) pressure, mean pressure and mean area. All runs and steps were included in the parameter Results are expressed as mean values (SD). *p<0.05 estimation. Mean values and standard deviations were calculated for all variables on both surfaces for Table 3 both movements. Statistical significance was set at the 0.05 probability level. Statistical Plantar pressure parameters for the midfoot analyses were performed using SPSS 17 (SPSS Inc, Chicago, IL, USA). Paired t-Tests were Baseline play Forehand play used to identify the differences between the two surface conditions. OptiCourt Clay OptiCourt Clay Maximum force (N) 241 (27) 207 (36) 236 (65) 275 (26) Peak pressure (kPa) 134 ( 17) 132 (21) 124 (26) 116 (7) Mean pressure (kPa) 40 ( 4) 34 (6) 39 (11) 45 (4) Results are expressed as mean values (SD). *p<0.05

Table 4 Plantar pressure parameters for the forefoot Baseline play Forehand play OptiCourt Clay OptiCourt Clay Maximum force (N) 664 (66) 588 (52) 507 (48) 550 (13) * Peak pressure (kPa) 312 ( 38) 350 (37) 255 (16) 289 (25) * Mean pressure (kPa) 135 ( 14) 120 (11) 103 (11) 112 (3) * Results are expressed as mean values (SD). *p<0.05

Table 5 Plantar pressure parameters for the hallux and lesser toes Figure 1: Regions defined for the X-Pedar insole. Baseline play Forehand play RESULTS: Plantar pressure parameters for both types of movements and both playing OptiCourt Clay OptiCourt Clay surfaces are presented for the whole foot (Table 1), the heel, midfoot and forefoot regions Maximum force (N) 393 (58) 419 (25) 367 (23) 427 (17) * (Tables 2, 3 and 4) and the region of hallux and lesser toes (Table 5). The concrete number Peak pressure (kPa) 373 ( 64) 458 (44) 351 (35) 458 (38) * of steps performed per trial was quite similar for all players and surfaces (e. g. 33 on average Mean pressure (kPa) 136 ( 20) 144 (8) 127 (8) 147 (6) * for the baseline play both on hard-court and on clay) and should be irrelevant for the Results are expressed as mean values (SD). *p<0.05 parameters determined. DISCUSSION: Plantar pressure measurements have been performed in order to get more Table 1 insight into the effect of the playing surface on the load in tennis. There are some indications Plantar pressure parameters for the whole foot which can be derived from this investigation. Significantly higher force and pressure values Baseline play Forehand play could be observed for the heel region on the hard-court. In the hallux and lesser toe as well OptiCourt Clay OptiCourt Clay as the forefoot region the results partly show significantly higher values on clay. A possible Maximum force (N) 1204 (134) 964 (64) * 969 (64) 1001 (47) explanation for these results could be the eventual need of higher pressure and force for Peak pressure (kPa) 39 8 ( 53) 460 (46) * 358 (38) 458 (38) * starting movements on the more slippery clay. Because of the properties of the hard-court Mean pressure (kPa) 152 (8) 131 (10) * 132 (6) 132 (5) the heel has to absorb higher forces when running. On clay the foot is able to roll more Results are expressed as mean values (SD). *p<0.05 smoothly resulting in more balanced force and pressure values. Higher loads for the hallux and lesser toe region on hard-court, as observed by Girard et al. Considering the whole foot, maximum force and mean pressure were significantly lower on (2007), could not be confirmed. Girard et al. (2007) gave a more aggressive play with an clay for the baseline play, whereas peak pressure was significantly higher for both tennis intensified forefoot running strategy as possible explanation for their finding. A more detailed specific movements (Table 1). Regarding the four defined regions, maximum force, peak and analysis of the single steps within a movement (force curves) might gain more insight into mean pressure were higher on hard-court for the heel region (Table 2) and higher on clay at these discrepancies. There are indications, for example, that on OptiCourt very high force the hallux and lesser toes region (Table 5) both for baseline and forehand play. No values occur during the change of the running direction (in the heel region), while on clay significant differences could be found for the midfoot region (Table 3). Significantly higher they can be observed during acceleration of the players (on the hallux and lesser toe region). values could be observed on clay for the forefoot region during forehand play (Table 4). CONCLUSION: This study shows that type of court surface affects plantar pressure distribution on the foot during tennis specific movements. A separation of the foot into four

ISBS 2011 602 Porto, Portugal Vilas-Boas, Machado, Kim, Veloso (eds.) Portuguese Journal of Sport Sciences Biomechanics in Sports 29 11 (Suppl. 2), 2011

After warming up the players performed two trials to get accustomed to the conditions of the TableTable 22 baseline play. A third trial was used for data recording and evaluation. The measurement of PlantarPlantar pressure pressure parameters parameters for for the the heel heel the forehand sequence was preceded by five forehand strokes, which were not evaluated. BaselineBaseline play ForehandForehand play play Inside plantar pressure was recorded using the X-Pedar insole (Novel GmbH, Munich, OptiOptiCCourtourt ClayClay OptiOptiCourtCourt Clay Clay Germany). The insole was placed between the foot and the plantar surface of the right shoe. MaximumMaximum force force (N) (N) 702 702 ( 77 (77) ) 4644 ((3030) )* * 645645 (70 ()70 ) 532 (53652) (65) The following parameters were determined for the whole foot and for four defined regions Peak Peakpressure pressure (kPa) (kPa) 329 329 ( 46 ( 46) ) 218 ((2626) )* * 298298 (45 ()45 ) 238 (22138) *( 21) * (heel, midfoot, forefoot, hallux and lesser toes; see Figure 1): Maximum force, peak MeanMean pressure pressure (kPa) (kPa) 21 212 2 ( 23 ( 23) ) 1400 ( (99) )* * 1951 95(21 ()21 ) 161 (16120) (20) pressure, mean pressure and mean area. All runs and steps were included in the parameter ResultsResults are expressed are expressed as asmean mean values values (SD). (SD). *p<0.05*p<0.05 estimation. Mean values and standard deviations were calculated for all variables on both surfaces for TableTable 33 both movements. Statistical significance was set at the 0.05 probability level. Statistical PlantarPlantar pressure pressure parameters parameters for for the the mid midfoofoot t analyses were performed using SPSS 17 (SPSS Inc, Chicago, IL, USA). Paired t-Tests were BaselineBaseline play ForehandForehand play play used to identify the differences between the two surface conditions. OptiOptiCCourtourt ClayClay OptiOptiCourtCourt Clay Clay MaximumMaximum force force (N) (N) 241 241 ( 27 (27) ) 207 ( 36(36) ) 236 236 (65 ()65 ) 275 (27526) ( 26) Peak Peakpressure pressure (kPa) (kPa) 134 134 ( 17 ( 17) ) 132 ( 21(21) ) 124 124 (26 ()26 ) 116 (1167) (7) MeanMean pressure pressure (kPa) (kPa) 40 40 ( 4 ( 4) ) 34 (6) (6) 39 39 ( 11 ()11 ) 45 (445) (4) ResultsResults are expressed are expressed as asmean mean values values (SD). (SD). *p<0.05*p<0.05

TableTable 44 PlantarPlantar pressure pressure parameters parameters for for the the fore forefoofoot t BaselineBaseline play ForehandForehand play play OptiOptiCCourtourt ClayClay OptiOptiCourtCourt Clay Clay MaximumMaximum force force (N) (N) 664 664 ( 66 (66) ) 588 ( 52(52) ) 507 507 (48) (48) 550 (55013) *( 13) * Peak Peakpressure pressure (kPa) (kPa) 312 312 ( 38 ( 38) ) 350 ( 37(37) ) 255 255 (16) (16) 289 (28925) *( 25) * MeanMean pressure pressure (kPa) (kPa) 135 135 ( 14 ( 14) ) 120 ( 11(11) ) 103 103 (11 ()11 ) 112 (1123) * ( 3 ) * ResultsResults are expressed are expressed as asmean mean values values (SD). (SD). *p<0.05*p<0.05

TableTable 55 PlantarPlantar pressure pressure parameters parameters for tthehe hallux hallux and and lesser lesser toes toes Figure 1: Regions defined for the X-Pedar insole. BaselineBaseline play ForehandForehand play play RESULTS: Plantar pressure parameters for both types of movements and both playing OptiOptiCCourtourt ClayClay OptiOptiCourtCourt Clay Clay surfaces are presented for the whole foot (Table 1), the heel, midfoot and forefoot regions MaximumMaximum force force (N) (N) 393 393 ( 58 (58) ) 419 ( 25(25) ) 367 367 (23) (23) 427 (42717) *( 17) * (Tables 2, 3 and 4) and the region of hallux and lesser toes (Table 5). The concrete number Peak Peakpressure pressure (kPa) (kPa) 373 373 ( 64 ( 64) ) 458 ( 44(44) ) 351 351 (35 ()35 ) 458 (45838) *( 38) * of steps performed per trial was quite similar for all players and surfaces (e. g. 33 on average MeanMean pressure pressure (kPa) (kPa) 136 136 ( 20 ( 20) ) 144 ( 8(8) ) 127 127 (8) ( 8 ) 147 (1476) * (6) * for the baseline play both on hard-court and on clay) and should be irrelevant for the ResultsResults are expressed are expressed as asmean mean values values (SD). (SD). *p<0.05*p<0.05 parameters determined. DISCUSSION:DISCUSSION: Plantar Plantar pressure pressure measurements measurements havehave been been performed performed in order in order to ge tot mor geet more Table 1 insightinsight into the into effect the effect of the of theplaying playing surface surface onon the loadload in in tennis tennis. There. There are someare some indications indications Plantar pressure parameters for the whole foot which whichcan be can derived be derived from from this this investigation. investigation. Significantly higher higher force force and andpressure pressure values values Baseline play Forehand play could becould observed be observed for thefor theheel heel region region on on the the hard--court.court. In In the the hallux hallux and and lesser lesser toe as toe well as well OptiCourt Clay OptiCourt Clay as the asforefoot the forefoot region region the theresults results partly partly show show significantly higher higher values values on clay.on clay.A possible A possible Maximum force (N) 1204 (134) 964 (64) * 969 (64) 1001 (47) explanationexplanation for these for these results results could could be be the the eventual eventual need need of ofhigher higher pressure pressure and force and forcefor for Peak pressure (kPa) 39 8 ( 53) 460 (46) * 358 (38) 458 (38) * startingstarting movements movements on theon themore more slippery slippery clay.clay. Because of of the the properties properties of the of hardthe- courthard -court Mean pressure (kPa) 152 (8) 131 (10) * 132 (6) 132 (5) the heelthe has heel to has absorb to absorb higher higher forces forces when when running. running. On On clay clay the the foot foot is able is able to roll to more roll more Results are expressed as mean values (SD). *p<0.05 smoothlysmoothly resulting resulting in more in more balanced balanced force force and and pressure values. values. HigherHigher loads loadsfor the for halluxthe hallux and and lesser lesser toe toe regionregion onon hardhard-court-court, a,s aobserveds observed by Girard by Girard et al. et al. Considering the whole foot, maximum force and mean pressure were significantly lower on (2007),(2007), could could not be not confirmed. be confirmed. Girard Girard et et al. al. (2007)07) gave gave a amore more aggressive aggressive play withplay awithn an clay for the baseline play, whereas peak pressure was significantly higher for both tennis intensifiedintensified forefoot forefoot running running strategy strategy as as possible possible explanationexplanation for for their their finding. finding. A more A more detailed detailed specific movements (Table 1). Regarding the four defined regions, maximum force, peak and analysisanalysis of the of singlethe single steps steps within within a amove movementment (force(force curves) curves) might might gain gain more more insight insight into into mean pressure were higher on hard-court for the heel region (Table 2) and higher on clay at these thesediscrepancies discrepancies. There. There are are indications indications,, for for example, example, that that on on OptiCourt OptiCourt very very high force high force the hallux and lesser toes region (Table 5) both for baseline and forehand play. No valuesvalues occur occur during during the thechange change of of the the running running directiondirection (in (in the the heel heel region), region), while while on clay on clay significant differences could be found for the midfoot region (Table 3). Significantly higher they canthey be can observed be observed dur ingduring acceleration acceleration of of thethe playersplayers (on (on the the hallux hallux and and lesser lesser toe region) toe region). . values could be observed on clay for the forefoot region during forehand play (Table 4). CONCLUSION:CONCLUSION: This This study study shows shows that that type type of of court court surface surface affects affects plantar plantar pressure pressure distributiondistribution on the on footthe footduring during tennis tennis specific specific movements. A Aseparation separation of the of footthe intofoot four into four

ISBS 2011 603 Porto, Portugal Vilas-Boas, Machado, Kim, Veloso (eds.) Portuguese Journal of Sport Sciences Biomechanics in Sports 29 11 (Suppl. 2), 2011 regions reveals different running styles during tennis specific movements depending on the EFFECT OF KINESIO TAPING ON PERFORMANCE IN COUNTER-MOVEMENT court surface. JUMP

Jakob Kümmel, Danica Mauz, Florian Blab and Manfred Vieten REFERENCES:

Dragoo, J.L. & Braun, H.J. (2010). The effect of playing surface on injury rate: a review of the current literature. Sports Medicine, 40(11), 981-990. Department of Sports Science, University of Konstanz, Germany Girard, O., Eicher, F., Fourcher, F., Micallef, J.P. & Millet, G.P. (2007). Effects of the playing surface on plantar pressures and potential injuries in tennis. British Journal of Sports Medicine, 41, 733-738. The purpose of this study was to identify the influence of taping with a flexible tape on jumping performance and its effects on the impulse in a stretch-shortening cycle Girard, O., Micallef, J.P. & Millet, G.P. (2010). Effects of the playing surface on plantar pressures movement. 23 subjects were divided in control group and intervention group. The during the first serve in tennis. International Journal of Sports Physiology and Performance, 5(3), 384- subjects participated in two trials of vertical counter-movement jumps. In the trial, the 393. knee extensors of the subjects in the intervention group were taped with an activating taping technique. Reaction forces of the jump were measured with an AMTI-force plate. Results showed no significant differences (ANOVA, p<0.05) between the two groups in both trials. Mean jumping height in Trial 1 was 0.38 ± 0.11 m (control) and 0.33 ± 0.05 m (intervention) compared to 0.35 ± 0.10 m (control) and 0.33 ± 0.05 m (intervention) in Trial 2. No improvements in jumping performance could be detected.

KEYWORDS: Kinesio tape, flexible taping, counter-movement jump, stretch-shortening cycle.

INTRODUCTION: In recent years the treatment of muscular and tendon injuries by flexible taping interventions (Kinesio tape) became popular in sports medicine and physiotherapy. An improvement of muscular strength and performance in sports was postulated by the producers of the tapes. There are some studies, which tried to investigate the effects of Kinesio taping on muscular activity (Janwantanakul & Gaogasigam 2005, Alexander et al. 2003), muscular strength (Fu et al. 2008, Slupik et al. 2007), and especially on jumping performance (Hisieh et al. 2007), but the results and conclusions of the effect of Kinesio taping were not uniform. Yet there are discrepancies to the correct taping technique in order to reach the desired effects. The purpose of this study was to investigate the effect of a taping method without any tension of the tape on jumping performance. By taping on knee extensors (m. vastus lateralis, m. vastus medialis), it is possible to detect a clear effect because of limited intervention on a single joint only.

METHODS: 23 subjects took part in the study. They were randomly divided into control and intervention group. The control group consisted of 6 female and 6 male subjects (age 25 ± 1.9 years, weight 71.3 ± 13.2 kg). 5 female and 6 male subjects (age 25 ± 2.2 years, weight 70.2 ± 14.1 kg) established the intervention group. The subjects performed two trials of a vertical jump. Three-dimensional ground reaction forces were measured by an AMTI force plate (Model OR6-6-2000, AMTI, Watertown/ USA). Every subject was briefly introduced into the test procedure before the measurement started. Counter-movement jumps were performed without a supporting arm-swing (arms close to the breast), starting position was upright standing on the force plate. The first trial included three maximal vertical jumps and delivered the data-baseline. For the second trial a y-shaped flexible tape (skin coloured Physiotape Kinseo Ltd., Kaltenkirchen, Germany) was applied to intervention group on the m. vastus lat. and m. vastus med. There was no tape applied to control group for the second trial. Subjects were taped according to the instruction manuals of a physiotherapist (Physio Training Academy Bühlertal, Germany) by one licensed person. There was a break of 15 minutes between those two trials, where all subjects rested in the same position. The second trial of three maximal vertical jumps followed. Data were recorded with a sampling rate of 1000 Hz and analyzed with the AMTI NetForce software. The statistical comparison of groups and trials was realized by a one-factor ANOVA for repeated measurement (=0.05). All statistical procedures were carried out using Statistica 6.0 (StatSoft Inc., Tulsa/ USA). The impulses of the jumps were calculated by integrating the force with respect to time. Jumping height ( ) was calculated by using the following formulas ( mass of the subject,

ISBS 2011 604 Porto, Portugal