Mutsumi Takahashi^*,1, Yogetsu Bando², Takuya Fukui^3,4

¹Department of Physiology, The Nippon Dental University School of Life Dentistry at Niigata, Japan

²Bando Dental Clinic, Ishikawa, Japan

³Department of Sport Science, Kanazawa Gakuin University of Sport Science, Ishikawa, Japan

⁴Japan Gymnastics Association Trampoline Committee, Tokyo, Japan

^*Corresponding author: Mutsumi Takahashi, Department of Physiology, The Nippon Dental University School of Life Dentistry at Niigata, Japan.

Received: 11 August 2025; Accepted: 18 August 2025; Published: 01 September 2025

Article Information

Citation: Mutsumi Takahashi, Yogetsu Bando, Takuya Fukui. Research on Jumping Height of Straight Jumps and Barani Jumps in Competitive Trampoline Gymnasts: Influence of Occlusal Correction. Fortune Journal of Health Sciences. 8 (2025): 822-827.

DOI: 10.26502/fjhs.342

Abstract

Keywords

Trampoline competition; Jump height; Straight jump; Barani jump; Posture control; Occlusion correction

Article Details

Introduction

The human body is always slightly swaying, and the body’s posture-control function maintains posture against this swaying [1]. Postural control involves sensory inputs from vision, vestibular sensation, somatosensation, and other sources. Information from these receptors is integrated in the central nervous system and output to the postural muscles to maintain postural stability [1-3]. The sensory input priority depends on the environment and situation, and there are interindividual differences [1]. When muscles are fatigued or damaged, sensory input from that area decreases while the contribution of other sensory inputs increases, and thus the importance of each sensory input for an athlete depends on the characteristics of the sport or event and the competitive level [4,5]. Somatic sensations are broadly divided into surface sensations and deep sensations. In addition, the periodontal ligament receptors, temporomandibular joint receptors, and muscle spindles of the jaw and neck muscles, which are related to occlusion, are affected by the occlusal contact state and clenching and may affect postural control.

Gymnastics is an athletic competition that emphasizes postural stability. Because gymnasts focus on balance training [6], their balance ability tends to be superior to that of the general public and athletes of other sports [4,5,7-10]. Gymnastics disciplines include artistic gymnastics, rhythmic gymnastics, trampoline, acrobatic gymnastics, and parkour [11], and the gymnasts that participate in each discipline have characteristic body shapes appropriate to their discipline [6,12]. Trampolines are used by athletes in various sports and events for training. From this, it can be inferred that the postural control functions of trampoline gymnasts have different characteristics from those of athletes in other sports.

The purpose of this study was to clarify the influence of occlusion, which is related to somatosensory input, on jumping height in competitive trampoline gymnasts. The null hypothesis was that occlusal correction has no effect on jumping height in trampoline gymnasts.

Materials and Methods

Participants

The participants were 13 male trampoline gymnasts (mean age, 17.5 ± 2.4 years) with normal occlusion and no subjective or objective morphological or functional abnormalities in the oral-maxillofacial system. They had an average duration of competitive experience of 11.8 ± 2.6 years and trained 6 times a week for 3 h per session.

This study was approved by the Ethics Committee of The Nippon Dental University School of Life Dentistry at Niigata (approval no. ECNG-R-443). The details of the study were fully explained to all participants and they provided written informed consent prior to their participation.

Occlusal correction method

To improve the occlusal contact state, a custom mouthguard was fabricated for each gymnast. A single-layer mouthguard was fabricated using a 2.0-mm-thick thermoplastic sheet (Sports Mouthguard; Keystone Industries, Cherry Hill, NJ) and a pressure-molding machine (Model Capture Try; Shofu Inc., Kyoto, Japan). The mouthguard was then adjusted to ensure even contact across all teeth with light clenching [10,12,13].

Measurement of postural control function

Postural control function was evaluated by using a cross-test with a center of gravity sway meter (GRAVICORDER GS-7; Anima Co., Ltd., Tokyo, Japan) [14,15]. Measurements were conducted both before and after the mouthguard intervention. During the measurement, the gymnasts were not instructed to close their mouth or clench; this was left to the gymnast’s discretion. The evaluation indices were the rectangular area calculated by multiplying the forward/backward and left/right movement distances of the center of foot pressure on the center of gravity trajectory diagram and the R/E value, which was the rectangular area divided by the outer circumferential area [14,15].

Recording the flight time of jumps and calculating the jump height

The trampoline trials comprised two types of jumps: straight jumps and barani jumps. For straight jumps, the gymnasts were instructed to perform 10 consecutive jumps after one preliminary jump. The barani jump is a trampoline technique in which the gymnast performs a 1/2 turn to the side while performing a 1-turn forward somersault. In this study, 10 consecutive barani jumps performed after one backward somersault were considered one trial. The flight time of the jumps was measured using an HDTS all-in-one measurement system (EU-7100; Eurotramp Trampoline Kurt Hack GmbH, Weilheim, Germany) [16,17]. The jump height (h) was calculated using the formula [h = 1/8 × acceleration (g) × flight time (t)²]. Measurements were taken at three time points: before the mouthguard intervention, immediately after the mouthguard intervention, and 2 months after the mouthguard intervention. The rate of increase in jump height immediately after the intervention or 2 months after the intervention was calculated compared with the before mouthguard intervention time point. No instructions on clenching or occlusion were given during the measurements. Gymnasts were instructed to wear the mouthguards a little less than half of the time during their practice days.

Statistical analysis

Statistical analysis was performed using SPSS ver. 17.0 (SPSS Japan Inc., Tokyo, Japan) and a P-value below 0.05 was considered significant. The Shapiro–Wilk test was used to test for normality. Normality was not observed in the rate of increase in jump height immediately after the intervention in straight jumps. Normality was met for all other variables.

Differences in the rectangular area or R/E values before and after the mouthguard intervention were analyzed using paired t-tests. A comparison of the jump height increase rate immediately after the intervention and 2 months after the intervention in straight jumps and barani jumps was analyzed using the Wilcoxon signed rank test or a paired t-test, respectively.

The rate of increase in the R/E value after the mouthguard intervention was calculated, and the correlation with the jump height increase rate 2 months after the intervention for each trial was analyzed using Pearson’s product–moment correlation coefficient. In addition, Pearson’s product–moment correlation coefficient was used to analyze the correlation between the rate of increase in jump height in straight jumps and barani jumps 2 months after the intervention.

Results

A comparison of the rectangular areas before and after the mouthguard intervention is shown in Figure 1 while a comparison of the R/E values is shown in Figure 2. The rectangular area was not significantly affected by the mouthguard intervention. In contrast, the R/E value was significantly higher after the mouthguard intervention (P<0.01).

Figure 1: Comparison of the rectangular area before and after the mouthguard intervention.

Figure 2: Comparison of the R/E value before and after the mouthguard intervention.

Figure 3 shows a comparison of the rate of increase in jump height immediately after the mouthguard intervention and 2 months after the intervention. For both straight jumps and barani jumps, the rate of increase in jump height was significantly greater 2 months after the mouthguard intervention than immediately after the intervention (P<0.01).

Figure 3: Comparison of the rate of increase in jump height. A: Straight jump. B: Barani jump.

Figure 4 shows the results of a correlation analysis between the rate of increase in the R/E value and the rate of increase in jump height 2 months after the intervention. For straight jumps, the higher the rate of increase in the R/E value, the higher the rate of increase in jump height, with a significant positive correlation (R=0.645, P<0.05). Similarly, for the barani jump, the higher the rate of increase in the R/E value, the higher the rate of increase in jump height (R=0.699, P<0.01).

Figure 4: Correlation between the rate of increase in the R/E value and the rate of increase in jump height. A: Straight jump. B: Barani jump.

Figure 5 shows the results of a correlation analysis of the rate of increase in jump height 2 months after the intervention for the straight jump and barani jump. A significant positive correlation was found: the greater the rate of increase in straight jump height, the greater the rate of increase in barani jump height (R=0.546, P<0.05).

Figure 5: Correlation between the rate of increase in jump height in straight jumps and barani jumps.

Discussion

The results of this study showed that occlusal correction through a mouthguard intervention improved postural control function, which, in turn, significantly improved jump heights in straight jumps and barani jumps in competitive trampoline gymnasts. Therefore, the null hypothesis was rejected.

Studies of postural stability and performance in gymnasts have found that balance ability is related to competition level, with elite gymnasts having better balance ability and significant relationships between balance ability and many performance indicators [5,18-22]. However, with regard to trampoline competitions, there are few reports regarding performance and postural control function, even though the sense of balance is emphasized in gymnastics events [23,24]. Our previous work has examined trampoline gymnasts by focusing on sensory input through occlusion. These studies revealed that occlusal correction using a mouthguard improves static balance [12] and that, in gymnasts with a good left–right balance of occlusal contacts, there is a correlation between the landing position and the direction of the displacement of the center of foot pressure in a straight jump [25]. In addition, the results showed that occlusal correction for gymnasts with poor left–right balance of occlusal contacts increases the flight time of straight jumps [17]. Based on these findings, the present study aimed to verify the effect of occlusal correction on dynamic stability in postural control and to examine its relationship with jumping skills.

In the evaluation of postural control function, no significant effect was found of the mouthguard intervention on the rectangular area, which reflects the displacement amount of the center of foot pressure. For the same rectangular area, the better the postural control function, the clearer the cross on the center of gravity trajectory diagram, and the R/E value has been reported as a numerical index of this relationship [14]. The R/E value was significantly higher after the mouthguard intervention, indicating that the occlusal intervention improved postural control function. Based on this, the relationship between the jump skill of competitive trampoline gymnasts was investigated based on the increase in the R/E value (i.e., improvement in postural control function) with the occlusal intervention.

The rate of increase in jump height for each trial due to the mouthguard intervention was significantly greater 2 months after the intervention than immediately after the intervention. Because the rate of increase showed a positive value immediately after the intervention, it can be assumed that occlusal correction using a mouthguard has a positive effect on trampoline competition skills. In addition, the significant improvement 2 months after the intervention indicates that a certain period of practice is necessary for each gymnast to become accustomed to the changes in occlusal sensation caused by the mouthguard and to acquire the skills to match their own jumping posture and movement timing. In particular, the improvement in jump height may be due not only to the augmentation of occlusal contact balance by the occlusal intervention method but also to the viscoelasticity of the mouthguard material [26]. In other words, compared with individuals not wearing the mouthguard, when clenching occurs in various jaw positions, more occlusal contact is possible using the mouthguard, which may be advantageous in stabilizing the body.

A positive correlation between the rate of increase in the R/E value and the rate of increase in jump height was observed in both trials. Additionally, as shown in Figure 2, the R/E value increased with the mouthguard intervention. These results revealed that improved postural control function contributes to improved jumping height. As a preliminary experiment, surface electromyographs were attached to the masseter muscles of gymnasts to record muscle activity during jumping. Muscle activity was observed from just before landing until the take-off motion in all gymnasts. The results suggest that occlusion may affect jumping skills in trampoline competitions during the phase from landing to taking off (i.e., during the take-off motion). This is also supported by the fact that the rate of increase in jump height for both straight jumps and barani jumps showed a positive correlation. Therefore, it is expected that occlusal correction will have a positive effect on the take-off movement regardless of the type of jump and may even have an effect on the overall score of trampoline routines.

This study used a mouthguard as a means of occlusion correction. Because the intervention was used with the aim of improving occlusal contacts, if the athlete’s own occlusal contacts are good, the intervention may have little impact or effect. This is the main limitation of this study and, in the future, we would like to increase the number of subjects and conduct additional studies to examine differences based on the occlusal contact state of athletes and the effects of the intervention on athletes with a good occlusal contact state.

Conclusion

The results of this study suggest that occlusal correction using a mouthguard improves the postural control function of trampoline gymnasts and thereby improves the jump height of straight jumps and barani jumps. It was also revealed that the effectiveness increased after 2 months of training.

Data Availability

The datasets collected and/or analyzed during the current study are available from the corresponding author on reasonable request.

Acknowledgments

This work was supported by JSPS KAKENHI Grant Number JP23K10617.

Conflicts of interest statement

The authors have no conflicts of interest relevant to this article.

References

1. Itaya A. Feedback system for sensory and postural control. J Biomech 39 (2015): 197-203.
2. Saito H. Mechanism of posture retention. General Rehabil 24 (1996): 699-703.
3. Nishimori T. Evaluation of postural stability. Kansai physic 3 (2003): 41-47.
4. Paillard T, Noé F. Effect of expertise and visual contribution on postural control in soccer. Scand J Med Sci Sports 16 (2006): 345-348.
5. Asseman FB, Caron O, Crémieux J. Are there specific conditions for which expertise in gymnastics could have an effect on postural control and performance? Gait Posture 27 (2008): 76-81.
6. Izumi T. Report on trampoline competitions that involved physical coaches: Physical training strengthening plan for the national team. NSCA JAPAN 25 (2018): 26-30.
7. Perrin PP, Deviterne D, Hugel F, et al. Judo, better than dance, develops sensorimotor adaptabilities involved in balance control. Gait Posture 15 (2002): 187-194.
8. Lion A, Gauchard GC, Deviterne D, et al. Differentiated influence of off-road and on-road cycling practice on balance control and the related-neurosensory organization. J Electromyogr Kinesiol 19 (2009): 623-630.
9. Paillard T, Margnes E, Portet M, et al. Postural ability reflects the athletic skill level of surfers. Eur J Appl Physiol 111 (2011): 1619-1623.
10. Takahashi M, Bando Y, Fukui T, et al. Equalization of the occlusal state by wearing a mouthguard contributes to improving postural control function. Appl Sci 13 (2023): 4342.
11. International gymnastics federation. FIG – Disciplines. FIG - International Gymnastics Federation (accessed on 23 Feb 2025).
12. Bando Y, Takahashi M, Fukui T, et al. Relationship between occlusal state and posture control function of trampoline gymnasts. J Sports Dent 23 (2019): 14-20.
13. Takahashi M, Bando Y, Kitaoka K, et al. Effect of wearing a mouthguard on physical ability is dependent on occlusal contact state: a study involving elite level female handball players. Dent Res Oral Health 6 (2023): 88-94.
14. Fukuyama K, Maruyama H. Relationships between the cross test and other balance tests. Phys Ther Sci 25 (2010): 79-83.
15. Takahashi M, Bando Y, Fukui T. Verification of relationship between static and dynamic balance using cross test trajectory diagram as indicator. Advances in Physical Education 14 (2024): 119-130.
16. Takahashi M, Bando Y, Fukui T. Effect of skeletal muscle mass and occlusal state on flight time of straight jumps in trampoline competition. Dental Research and Oral Health 6 (2023): 52-57.
17. Takahashi M, Bando Y, Fukui T, et al. Influence of occlusion on flight time in trampoline competition. Int J Dent Oral Health 9 (2023): 405.
18. Asseman F, Caron O, Crémieux J. Is there a transfer of postural ability from specific to unspecific postures in elite gymnasts? Neurosci Lett 358 (2004): 83-86.
19. Carrick FR, Oggero E, Pagnacco G, et al. Posturographic testing and motor learning predictability in gymnasts. Disabil Rehabil 29 (2007): 1881-1889.
20. Hrysomallis C. Balance ability and athletic performance. Sports Med 41 (2011): 221-232.
21. Floría P, Gómez-Landero LA, Harrison AJ. Centre of pressure correlates with pyramid performance in acrobatic gymnastics. Sports Biomech 14 (2015): 424-434.
22. Zemková E, Zapletalová L. The Role of neuromuscular control of postural and core stability in functional movement and athlete performance. Front Physiol 24 (2022): 796097.
23. Natrup J, Bramme J, Lussanet MHE, et al. Gaze behavior of trampoline gymnasts during a back tuck somersault. Hum Mov Sci 70 (2020): 102589.
24. Baba T. Study on jumping ability of male trampoline gymnasts. Mod Biz Soc 6 (2020): 37-46.
25. Takahashi M, Bando Y, Fukui T, et al. Straight jump landing position of trampoline gymnasts with stable occlusal balance reflects standing postural control function. Appl Sci 13 (2023): 6689.
26. Takeuchi M, Togaya N. Effectively of thermoforming process for fabricating of intraoral apparatus. Tokyo, Japan, Sunashobo (2006): 23-28.