Journal of Athletic EnhancementISSN: 2324-9080

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Research Article, J Athl Enhancement Vol: 0 Issue: 0

The Effects of a Static and Dynamic Balance-Training Program in Female Volleyball Players

Jenna Sawdon-Bea1* and Nicole Sandino2
1Department of Physical Therapy, California State University, Fresno, California, USA
2Physical Therapist, Barrows Physical Therapy, Fresno, California, USA
Corresponding author : Jenna Sawdon-Bea
Assistant Professor, Department of Physical Therapy, California State University, 2345 E. San Ramon Avenue, M/S MH29, Fresno, CA 93740-8031, USA
Tel: 559-278-6376; Fax: 559-278-3635 E-mail: [email protected]
Received: January 15, 2015 Accepted: March 09, 2015 Published: March 14, 2015
Citation: Sawdon-Bea J, Sandino N (2015) The Effects of a Static and Dynamic Balance-Training Programin Female Volleyball Players. J Athl Enhancement 4:1. doi:10.4172/2324-9080.1000189

Abstract

The Effects of a Static and Dynamic Balance-Training Program in Female Volleyball Players

Acute ankle injuries are prevalent in female volleyball players. Despite relatively mild severity and time away from sport, most individuals will experience recurrent sprains. Based on the high incidence rate of ankle injuries in female volleyball players, the purpose of this study was to determine the effects of a 6-week static and dynamic balance training program on self-reported disability and functional reach.

Keywords: Ankle sprains; Balance training; Volleyball; Star Excursion Balance Test (SEBT); Foot and Ankle Disability Index (FADI); High school; Dynamic balance

Keywords

Ankle sprains; Balance training; Volleyball; Star Excursion Balance Test (SEBT); Foot and Ankle Disability Index (FADI); High school; Dynamic balance

Introduction

Ankle injuries are the most prevalent in athletes between 14-18 years of age. Volleyball is one of the world’s most popular team sports, second only to soccer [1,2]. Acute ankle injuries are one of the most prevalent injuries to occur in female volleyball players, and have the highest proportion of ankle injuries among all high school athletes [3-5].
Although ankle injuries, particularly sprains, are considered mild in terms of severity and time away from sport [6], most individuals will continue to experience recurrent sprains and instability within the joint. Research regarding ankle sprains indicates patients are at higher re-injury risk with low-grade acute lateral ankle sprains, at two times greater risk within a year for re injury, and at increased risk of sprains throughout their career once it has occurred [7-11].
Chronic Ankle Instability (CAI) can result from recurrent ankle sprains with ensuring diminished neuromuscular control [12,13], muscle weakness [14], subjective reports of pain [15], impaired performance during functional tasks [16,17], and perceived difficulties with activities of daily living (ADLs) and sport-specific skills [18]. Research indicates that there are altered patterns of muscular activation in the stabilizing muscles of the foot-ankle complex in volleyball players with ankle instability [19]. Additionally a systematic review on the treatment of acute ankle ligament injuries reported that balance training is effective in athletes with previous sprains [20].
Proper balance control is an important part of ankle sprain prevention because it involves processing of visual, vestibular, and somatosensory inputs together to control how the body moves in space. A proposed theory for ankle sprain prevention is that balance training promotes neuromuscular mechanisms that cause a cocontraction of the antagonist and agonist muscles, which enhance stability [21]. With increased stability, joint dysfunction is much less likely to take place due to less strain on the ligaments. Following a sprain, there is decreased balance and proprioceptive feedback from the ankle, thus, a treatment strategy for prevention of ankle sprains should include proprioceptive training.
There is a lack of consensus regarding the ideal training dosage for balance training with ankle sprains. Although previous systematic reviews report postural control improvements as a result of balance training, the exact treatment dosage necessary to see improvements was not clear [22-24]. While two studies reported improvements in athletes with acute ankle sprain after just 3 days of balance training [25,26], others concluded that improvements in athletes with chronic ankle instability were not seen until four, six or eight weeks [27- 29]. At best, a systematic review by Zech et al. [30], hypothesized that sensorimotor adaptations require a minimum balance training duration of at least 6 weeks. Therefore, based on the high incidence rate of ankle injuries in female volleyball players and the research on positive results with extended balance training, the purpose of this study was to determine the effects of a 6-week static and dynamic balance training program on self-reported disability (as measured with the Foot and Ankle Disability Index) and functional reach (as measured with the Star Excursion Balance Test). It was our hypothesis that this program would result in improvements in star excursion balance test (SEBT) reach distances, and self-reported function.

Methods

Participants
Twenty-one female volleyball players between the ages of thirteen and sixteen (M=14 years) were recruited on a volunteer basis from three local intermediate and high schools within the Fresno and Clovis, California area. Ninety percent of participants reported the right leg as their dominant lower extremity and all reported at least four years of active involvement within the sport. Forty-two percent of the participants reported a prior ankle sprain. Of those, sixty-seven percent reported experiencing two or more ankle sprains in the past four years. Almost half of all participants (47.6%) reported using some form of supportive device for the ankle, including ankle braces and/or athletic tape.
All participant’s guardian read and signed a consent form approved by the university’s institutional review board. All participants completed an information questionnaire in order to gather demographic information.
Participants were excluded from the study if informed consent was not provided and if they had experienced a fracture or any type of surgery to the left or right lower extremity within two months prior to testing. Testing and intervention took place during the spring competitive club season at the gymnasiums where practices were held.
Instrumentation
Foot and Ankle Disability Index (FADI): Participants completed the Foot and Ankle Disability Index (FADI) including the FADISport module, for analysis of subjective impairment. The FADI contains twenty-six questions related to function with four questions specifically related to pain (Table 1). The Sport module consists of eight questions regarding impairment to sport-related activities such as running, jumping, and landing. Items are scored 0 (unable to do) to 4 (no difficulty) with the four questions in the pain subsection scored similarly (0 equating to unbearable pain and 4 equating to no pain). All three subsections were scored separately (FADI-88 points, FADIPain subsection- 16 points, FADI-Sport subsection- 32 points) as well as the overall score (136 points). The FADI, FADI-pain and FADISport are scored separately as percentages, with 100% representing no dysfunction. The FADI and FADI Sport have showed measured improvement in function following rehabilitation of athletes [18,31]. Specifically, FADI scores indicated a change after four weeks of balance training exercises with chronic ankle instability participants. Further, both the FADI and the FADI Sport scores improved after the rehabilitation, however greater improvement was seen in the FADI Sport scores, suggesting it may be more sensitive than the FADI in athletes [18].
Table 1: Foot and Ankle Disability Index*.
Star Excursion Balance Test (SEBT): Originally described by Gray [32] as a rehabilitative tool, the SEBT is a series of singlelimb squats using the nonstance limb to reach maximally to touch a point along one of eight designated lines on the ground. The lines are arranged in a grid that extends from a center point and are forty-five degrees from one another. Three directions were utilized for this research based on studies that indicate great redundancy in participant performance in the original eight reach directions [33]. This study, therefore, recommended that only three reach distances (anterior, posteromedial and posterolateral) be performed with the SEBT [33].
The SEBT was administered in order to test participant’s dynamic postural control. Although validation and reliability has not been reported on female volleyball players, the SEBT is a good predictor of lower extremity function among high school basketball players as well as an effective tool to assess reach deficits among those with chronic ankle instability [17,34]. Despite lack of validity studies on volleyball athletes, basketball and volleyball share common movements, such as sharp cutting maneuvers and jumping, often jumping off of and landing with one foot. Therefore, it was reasoned that the SEBT was a suitable test to administer to this group of athletes.
Protocol for administration of the SEBT was adapted from guidelines set by Plisky et al. [34]. The greatest reach distance from three proper trials was used for data comparison. The order of reach directions was randomly selected to avoid nonrandomized order effect on the data. Prior to data collection, intra-rater reliability was established for the SEBT (r=0.92).
Procedures
All participants performed pretests for the FADI and SEBT. The intervention protocol was performed two days per week for six weeks. The intervention protocol consisted of 6 exercises which are described in Table 2. As the evidence has demonstrated that externally applied devices do not affect SEBT performance [35-38], participants were permitted to wear their ankle brace(s) during the exercise intervention. At the end of six weeks, posttest measures for FADI and SEBT were repeated.
Table 2: Intervention Protocol that was performed 2 times per week for 6 weeks.
Data analysis
Pretest and posttest scores on total FADI score and the three subsections (FADI subsection, the Sport Module subsection, and the Pain subsection) were analyzed using a Mann-Whitney U test. The means of each participant’s pretest and posttest measurements on the SEBT (anterior, posteriolateral and posteromedial directions) were analyzed with a paired t-test. All data was inputted into statistical program SPSS® (v20.0 for Windows). Variables were considered statistically significant with a P<0.05.

Results

Foot and Ankle Disability Index (FADI)
Results of the Mann-Whitney U test revealed no significant difference between pre and posttest measures on the components of the FADI, as well as the total score (Table 3).
Table 3: Pre and Post-measures of the FADI scores.
Star Excursion Balance Test (SEBT)
Performance on the pre and post SEBT between measures revealed significant differences in functional reach for all three directions on the left stance limb (P<0.01 for all three measures). Significant improvements (P<0.05) were found during functional reach of the right lower extremity (right lower extremity stance) in the anterior (P=0.01) and posteromedial directions (P=0.02), however not in the posterolateral direction (P=0.24) (Table 4).
Table 4: Comparison of Baseline and Post-Intervention Mean Scores for the SEBT.

Discussion

The results of this study revealed that functional reach, as assessed by the SEBT, can be improved after a six week static and dynamic balance program in this population of adolescent female volleyball players. The balance training protocol designed for this study utilized a combination of dynamic and static balance training while incorporating the sport specific tasks necessary for optimal performance such as, single-limb stability.
A major goal of this study was to create an effective intervention that was brief to administer, and that would improve the participant’s single limb balancing abilities. At the conclusion of the study, coaches were asked about the duration of time required to administer all exercises, with the average length of time reported to be ten minutes. Pau, Loi and Pezzotta [6] also reported positive effects of balance training for volleyball players, however, this protocol may not be enticing to coaches as the combination of activities lasted approximately twenty to thirty minutes. The protocol used in this research was carried out as part of the warm-up prior to practice and was completed in approximately 10 minutes. The next step for this intervention is to implement the balance program with the hopes of reducing the overall number of ankle sprains in volleyball players, regardless of whether they have had a prior ankle sprain.
A systematic review done by Petersen et al. [20] reviewed three prospective randomized studies on the effect of balance board training for the prevention of ankle sprains in athletes and it showed that a balance training program significantly reduces the risk of ankle sprains in a subgroup of athletes with a previous sprain [39-41]. In addition, Verhagen et al. [41] reported that the cost of preventing one ankle sprain was $444.03. Implementing a balance program such as the one investigated, could reduce overall costs associated with the treatment of ankle sprains.
Similar to this studies finding, Trojan and McKeag [42] reported success with static and dynamic programs working on proprioception in a cohort study of two hundred and thirty male and female high school and collegiate athletes. Single leg balance test scores and the likelihood of a future ankle sprain were assessed, and significant association was reported with a low single leg balance test and future ankle sprains. While this study did not track the athletes longitudinally, it will be important to examine in future studies.
Comparatively, these results are similar to studies of which the static and dynamic training program was adapted [27,43,44]. After balance interventions, other authors noted significant improvements in the posteromedial and posterolateral reach directions, however, there were no reported improvements in the anterior direction. In con -trast, this study revealed statistically significant improvements in bilateral posteromedial reach, bilateral anterior reach, as well as left stance posterolateral reach. It is hypothesized that improvements not seen in the posterolateral direction of right stance may be due to the nature of volleyball attacking and blocking maneuvers. Although the majority of offensive and defensive jumps occur symmetrically (left and right lower extremity take-off), up to thirty-five percent of offensive landing, and sixteen percent of defensive landing occur, with the left limb [45]. This repetitive jumping and landing on the left lower extremity could potentially create a muscular imbalance between lower limbs. Because of this imbalance, the left lower extremity is stronger than the right, and it could help explain why improvements in SEBT reach distances did not occur for every position on the right stance limb. Furthermore, during an attack maneuver in volleyball, players are taught to contact the ball as high as they can. This imposes a lateral trunk flexion moment in the opposite direction of the attacking upper extremity. Since one hundred percent of participants reported rightside upper extremity dominance, this increases the likelihood of a left lateral trunk flexion following an attack and therefore an increased likelihood of landing with the left foot. By landing less often on the right lower extremity, we theorize that there was less sport-specific carryover from this balance program on the right lower extremity in the right stance posterolateral reach maneuver.
While statistically significant improvements with SEBT measures were found in this study, it is important to assess whether this change score is clinically meaningful. Hoch et al. [46] reported minimal detectable change (MDC) scores for the SEBT in the anterior direction, posteromedial, and posterolateral directions in a population of twenty individuals with chronic ankle instability. The MDC for the anterior SEBT was reported at 1.6%, the posteromedial SEBT at 3.4% and the posterolateral at 4.3% [46]. In this study, the MDC was exceeded for all measures on the left stance leg (anterior SEBT 9.4%, posterolateral SEBT 9.3%, and posteromedial 10.2%) and for the anterior SEBT and posteromedial SEBT on the right stance limb (5.0% and 7.2% respectively). While measures on the right stance limb for the posterolateral SEBT did not reach statistical significance (P=0.24), nor did they exceed the MDC of 4.3% as published by Hoch et al. [46].
Improvements in dynamic-balance reach distances in this population area noteworthy as literature reports that adolescence is a time of rapid musculoskeletal growth and decreased balance and coordination [47-49]. Musculoskeletal growth during puberty, in the absence of corresponding neuromuscular adaptation, may facilitate the development of “neuromuscular imbalances” [50]. If not addressed, these imbalances may continue through adolescence into maturity and predispose female athletes to increased risk of injury. However, similar to this study, there is literature that reports neuromuscular training, at or near the onset of female puberty, may improve single-leg balance and reach distances as measured by the SEBT [51-53]. McLeod et al. [53] reported improvements in SEBT reach distances after a 6-weeek neuromuscular program that included plyometric, functional strengthening, balance, and stability ball exercises in a population of 37 female high school volleyball players. Research supports that an improvement in reach distance creates an increase in the demands placed on balance and the neuromuscular system [54]. Therefore, training timed with growth and development during adolescence, may reduce injury risk.
The results for the FADI were not similar to past studies [27,43,44]. Statistical improvements were not observed following our intervention. This is possibly due to very high scores prior to the initiation of balance training. If we take the total FADI score as a percentage, with a perfect score corresponding to 100% and no perceived dysfunction, then the mean of the total FADI score prior to balance training would equate to 93%; relatively little disability assumed at the ankle. At the conclusion of the six-week intervention the total FADI score improved to 95%; perhaps indicative of a positive trend. However, as mentioned, this improvement was not great enough to warrant statistical significance. With this in mind, the minimal detectable change and the minimal clinically important difference for the FADI have not been addressed in the literature. Therefore, one must wonder if clinically, an increase of two percentage points in female volleyball players is important.
Of interest in this study is that participants rated themselves lowest on the FADI Sport section. This section asks the participants to rank their difficulty with such sport-specific tasks as running, jumping, landing, cutting / lateral movements, and / or squatting or stopping quickly. The FADI Sport section has been reported to be more sensitive at detecting deficits and is recommended for use among high-functioning individuals [18]. At baseline, and at posttesting, participants rated themselves as functioning at 90%. One hypothesis for this reported lack of improvement is that the six-week intervention was not long enough for participants to feel that their sport skills improved. While our program was two sessions per week, other authors have reported training programs that were three to five times per week for eight weeks [55,56].
When interpreting the results of this study, the largest limitation to consider is the small sample size of 21female adolescent volleyball players. Therefore, further investigations on a larger, more diverse population is recommended. In addition, future research will be needed to assess whether this exercise program can reduce ankle injuries prospectively.

Conclusion

A six-week dynamic and static balance protocol was effective in improving functional reach and dynamic stability performance in this population of adolescent female volleyball players. In addition, this quick and easy training protocol could be implemented by coaches in hopes of reducing the incidence of ankle injuries. The findings support continuing the current clinical practice of balance/proprioception training to address ankle injuries.

Conflict of Interest

No disclosed conflicts of interest.

Ethical Approval

This study was approved by the Institutional Review Board at California State University, Fresno.

Funding

No sources of funding were provided for this study.

Acknowledgments

The authors wish to thank the volleyball players and coaches for participating in the program.

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