Preamble

Research on the Lateralization of Dynamic and Static Balance in Volleyball Players

Oct. 2025 10. 11776 / j. issn. 1000-4939. 2025. 05. 021. School of Sports Training, Tianjin University of Sport; School of Social Sports, Tianjin University of Sport; School of Sports Health, Tianjin University of Sport; School of Sports Economics and Management, Tianjin University of Sport; Tianjin Virtual Simulation Experimental Teaching Center for Sports Injury and Rehabilitation. This study analyzes the biomechanical characteristics of the dominant and non-dominant legs of volleyball players during single-leg standing and single-leg landing. By exploring the differences in dynamic and static balance capabilities between the dominant and non-dominant legs, this research aims to provide a theoretical foundation for the design of posture control training programs for volleyball athletes.

A group of volleyball players underwent stability testing on both their dominant and non-dominant legs, involving single-leg standing (with eyes open and eyes closed) and single-leg landing from a 40 cm box. The study compared several key metrics, including static standing center of pressure (COP) parameters, joint angles at the moment of initial contact, joint range of motion, stability indices, loading rates, peak ground reaction forces, and the time required to reach peak ground reaction force.

结果

1) Static Balance Ability: There were no significant differences observed between the non-dominant and dominant legs during the single-leg stance test with eyes open ($P > 0.05$). However, during the single-leg stance with eyes closed, the maximum displacement and average velocity in the anterior-posterior (AP) direction showed significant differences in the dominant leg compared to the non-dominant leg ($P < 0.05$).

2) Dynamic Balance Ability: Significant differences were found between the non-dominant and dominant legs regarding the Anterior-Posterior Stability Index (APSI), Medial-Lateral Stability Index (MLSI), Vertical Stability Index (VSI), and Dynamic Postural Stability Index (DPSI) calculated during single-leg landings ($P < 0.05$). During the landing stabilization process, the range of motion (ROM) of the knee and ankle joints in the non-dominant leg differed significantly from those in the dominant leg ($P < 0.05$). Furthermore, the vertical loading rates calculated during single-leg landings showed significant differences between the dominant and non-dominant legs ($P < 0.05$), and the Symmetry Index (SI) for the loading rate indicated the presence of functional lateralization.

结论

There is a distinct lateral asymmetry in the balance capabilities between the dominant and non-dominant legs of volleyball athletes. Regarding static balance, the performance of both lower limbs is similar when the eyes are open; however, with eyes closed, the dominant leg exhibits superior static balance in the sagittal plane, whereas the non-dominant side relies more heavily on visual compensation.

In terms of dynamic balance, the non-dominant leg outperforms the dominant leg, further indicating a lateralization between the two limbs. Consequently, volleyball strength and conditioning programs should prioritize and strengthen the closed-eye static balance of the non-dominant leg and the dynamic postural control of the dominant leg. Addressing these specific deficits can help mitigate the risk of landing injuries and enhance athletic performance during single-leg support and power-generation movements.

关键词

Volleyball Players; Dynamic and Static Balance Ability; Laterality; Sports Injury
CLC Number: G804.63 Document Code: A Article ID:

Abstract

Balance ability is a critical physical quality for volleyball players, playing a vital role in the execution of technical movements and the prevention of sports injuries. This study aims to investigate the characteristics of static and dynamic balance in volleyball players, with a particular focus on the phenomenon of laterality and its potential correlation with sports injuries. By analyzing the postural control stability of athletes in different states, this research provides a theoretical basis for optimizing training programs and developing injury intervention strategies.

Introduction

Volleyball is a high-intensity, explosive sport that requires athletes to frequently perform complex movements such as jumping, landing, rapid changes of direction, and lunging. These actions place extremely high demands on the body's neuromuscular control and balance stability. Balance ability is generally categorized into static balance—the ability to maintain the body's center of gravity over a base of support while stationary—and dynamic balance—the ability to maintain stability during movement or after external perturbations.

In competitive volleyball, the repetitive nature of asymmetrical technical movements (such as one-handed spiking or specific footwork patterns) often leads to the development of "laterality" or functional asymmetry between the dominant and non-dominant limbs. While some degree of asymmetry is a natural adaptation to specialized training, excessive imbalances in strength or stability between limbs are frequently cited in the literature as significant risk factors for lower extremity injuries, particularly involving the ankle and knee joints.

1. Static and Dynamic Balance in Volleyball

1.1 Static Balance Characteristics

Static balance in volleyball players is often assessed using force plates to measure the displacement of the Center of Pressure (COP). Research indicates that elite volleyball players demonstrate superior static postural control compared to non-athletes, characterized by smaller sway areas and lower velocity of COP movement. This stability is essential for maintaining a ready position and executing precise overhead passes or serves.

1.2 Dynamic Balance Characteristics

Dynamic balance is perhaps more critical for volleyball performance, as most injuries occur during the landing phase of a jump or during sudden lateral movements. The Star Excursion Balance Test (SEBT) or the Y-Balance Test (YBT) are commonly used to evaluate dynamic stability. These tests measure the athlete's ability to reach in various directions while maintaining single-leg stability, reflecting the integration of proprioception, range of motion, and neuromuscular strength.

Study of lateralization in dynamic and static balance abilities of volleyball players FU Guangliang BAO Chunyu MENG Qinghua ZHOU Luxing SUN Jiawei ZHANG Nan

1. School of Sports Training

Tianjin University of Sport

301617 Tianjin

China

2. School of Social Sports

Tianjin University of Sport

301617 Tianjin

China

3. School of Sports Health

Tianjin University of Sport

301617 Tianjin

China

4. School of Sports Economics and Management

Tianjin University of Sport

301617 Tianjin

China

301617 Tianjin

China

Abstract

Objective To analyze the biomechanical characteristics of single-leg stance and single-leg landing in the dominant and non-dominant legs of volleyball players and explore the differences in static and dynamic balance abilities between the two legs so as to provide theoretical guidance for the design of posture control training programs for volleyball players.

Methods

Twenty volleyball players were selected to perform -second single-leg stance tests with eyes open and closed cm box jump single-leg landing stability tests using both the dominant and non-dominant legs.

The study compared the differences in center of pressure parameters during static stance joint angles and range of motion at the moment of ground contact during landing stability index loading rate peak ground reaction force and the time to reach peak ground reaction force.

Results

Static balance ability No significant differences were observed in COP parameters between the dominant and non-dominant legs during single-leg stance with the eyes open ＞0. 05 . However during single-leg stance with the eyes closed the maximum displacement and average velocity of COP in the anterior-posterior direction of the dominant leg showed significant differences compared to the non-dominant ＜0. 05 Dynamic balance ability Significant differences were found between the dominant and non-dominant legs in the anterior-posterior stability index lateral stability index vertical stability index and dynamic stability time calcu- lated from GRF during single-leg landing . During the landing cushioning phase significant differences in knee and ankle joint mobility were observed between the non-dominant and dominant legs . Additionally the load- ing rate during single-leg landing showed significant differences between the two legs and the loading rate symmetry index indicated lateralization.

Conclusion

There is lateralization in the balance abilities between the domi- nant and non-dominant legs of volleyball players. In terms of static balance ability the two legs exhibit similar perform- ance under eyes-open conditions. However under eyes-closed conditions the dominant leg demonstrates better static bal- ance in the sagittal plane while the non-dominant leg relies more on visual compensation. In terms of dynamic balance a- bility the non-dominant leg performs better than the dominant leg indicating lateralization between the two legs. In desig- ning physical training programs for volleyball players special attention should be paid to enhancing the static balance abili- ty of the non-dominant leg under eyes-closed conditions and improving the dynamic posture control of the dominant leg.

This will help reduce the risk of landing injuries and improve the performance of single-leg support and force application movements.

Keywords: volleyball player; static and dynamic balance ability; lateralization; sports-induced injury.

In various ball games involving jumping and landing, single-leg balance ability is crucial for the development of motor skills, particularly for volleyball players who possess a high center of gravity. Superior single-leg balance helps volleyball players maintain bodily stability and precise control when executing technical maneuvers such as single-leg jumps, lateral support jumps, and approach spikes. Furthermore, proficient dynamic single-leg balance can reduce lower limb injuries during landing. However, current research on balance ability often assumes lower limb symmetry, evaluating balance based on data from only one side or selecting only the stability of the dominant leg as the evaluative basis. This approach does not align with actual sporting conditions. During competition, athletes frequently use one leg to execute complex or power-based movements while using the other leg for support and balance—a phenomenon known as lateralization. First proposed by the neurophysiologist Brown, lateralization has been proven to be a contributing factor to injury rates. This functional differentiation and postural variation between the lower limbs significantly impact an individual's athletic performance. Despite this, the lateralization effect on the lower limb balance of volleyball players has been overlooked, and there are few reports regarding whether differences exist between the dominant and non-dominant legs.

Based on these considerations, this study conducts a comparative analysis of kinematics, kinetics, loading rates, and stability indices between the dominant and non-dominant legs of volleyball players during single-leg standing and single-leg landing tasks. By evaluating the differences between the lower limbs during static and dynamic single-leg balance tasks, this research aims to provide reference data for enhancing athletic performance and injury prevention.

1 研究方法

In [Month], volleyball athletes were recruited in Tianjin to participate in this experimental study. The sample size was determined using G*Power 3.1 software. By selecting a large effect size and a significance level of $\alpha = 0.05$, the required total sample size was calculated to be [N]. To account for potential attrition or invalid data, additional participants were included in the final recruitment.

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...sample attrition, a total of [N] subjects were ultimately selected, including [N] first-class and [N] second-class athletes. All participants had no lower limb injuries within the past [N] months and were free of neurological disorders or chronic non-communicable diseases. This study was approved by the Ethics Committee of the Tianjin University of Sport (TJUS2023-050).

Static Balance Testing

A three-dimensional force plate system was utilized to collect data during both open-eye and closed-eye standing tests. The sampling frequency was set at 1,000 Hz. The Bioware software was employed to extract the center of pressure (COP) from the recorded plantar pressure data. Subsequently, the data underwent low-pass filtering with a cutoff frequency of [N] Hz.

10 Hz

Static balance was assessed by quantifying body sway. During the test, subjects were instructed to fixate their gaze on a stationary point directly in front of them, place their hands on their hips, and stand on a single leg. The non-testing leg was positioned such that the lower leg was perpendicular to the testing leg while the thigh remained parallel to it. Throughout the procedure, the testing leg was required to remain stationary without any positional displacement. The test was performed alternately on both legs for a total of three trials per leg, with a 1-minute rest interval between trials. The starting leg for each subject was determined randomly, as shown in [FIGURE:1].

Dynamic balance was evaluated using a three-dimensional force plate system and a three-dimensional motion capture system to collect data during a single-leg landing from a 40 cm high box. The sampling frequency for these measurements was set at 1,000 Hz.

In this study, the dominant leg was identified using the ball-kicking method commonly employed in previous research. Prior to testing, subjects were asked to kick a ball with maximum effort three times using each leg; the leg that achieved the greatest kicking distance was defined as the dominant leg.

To analyze static balance stability, the $X$ and $Y$ axis coordinates exported from the Bioware software—representing medial-lateral (ML) and anterior-posterior (AP) displacements, respectively—were used for calculations. The specific metrics included:
- The maximum displacement in the anterior-posterior direction ($MAX_{ap}$)
- The maximum displacement in the medial-lateral direction ($MAX_{ml}$)
- The mean velocity in the anterior-posterior direction ($MVEL_{ap}$)
- The mean velocity in the medial-lateral direction ($MVEL_{ml}$)
- The 95% confidence ellipse area of the Center of Pressure (95% COP area)

200 Hz

The athletes were required to stand on a plyometric box, with the testing leg lifted off the surface and positioned at the edge of the box. The body's center of gravity was gradually shifted forward; once the projection of the center of gravity moved beyond the edge of the box, the athlete descended in a free-fall manner. They were instructed to land on a single leg in the center of the force plate, ensuring there was no initial vertical velocity at the moment of descent. Upon landing, the testing leg performed a natural knee flexion for cushioning and maintained this buffered posture, while the non-landing leg was naturally bent backward.

The criteria for a failed test included: the supporting leg moving from its original position after landing; abnormal trunk forward lean or swaying after landing; the non-landing leg making contact with the landing leg or the box; or the athlete performing obvious adjustment movements (such as sudden pauses or rapid swinging) after landing. The landing standards were identical for both the dominant and non-dominant legs. During testing, the legs were alternated for each trial, with a 1-minute interval between attempts. The 40 cm box height selected for this study was based on the heights used in lateral dynamic single-leg drop landing balance tests for athletes in other sports, such as tennis \cite{1} and soccer \cite{2}. This height selection facilitates comparative analysis across different sporting disciplines.

Furthermore, existing research has documented that the jump heights of volleyball players during competition typically range from 35 to 50 cm. Therefore, selecting a box height of 40 cm not only aligns with the actual jumping heights of volleyball players but also accurately simulates the athletic state of players during a match. This provides appropriate experimental conditions for testing dynamic balance capabilities.

The sway area ($S$) was calculated using the following formula:

i = 1 y i+ 1 - y i t i+ 1 - t i （ 3 ）

K v = 1 N ∑

i = 1 x i+ 1 - x i t i+ 1 - t i （ 4 ）

K u = 1 N ∑

The maximum and minimum values in the longitudinal (forward-backward) direction are determined accordingly. The average velocity in this direction is calculated by dividing the displacement between the positions at $n$ adjacent time steps by the corresponding time interval, subsequently taking the absolute value of the result.

value, and then calculate the average across all points; the area of the ellipse. $\text{COP}$ represents the movement trajectory of an athlete during the experimental testing process. As can be observed intuitively from the figure, when the athlete maintains balance in a standing position, the center of pressure (COP) changes continuously over time, exhibiting persistent fluctuations in both the anterior-posterior (AP) and medial-lateral (ML) directions.

Dynamic Balance Ability

Joint angles at the moment of initial contact: This refers to the three-dimensional angles of the three lower limb joints (hip, knee, and ankle) at the instant of landing. The moment of landing is defined as the point at which the vertical ground reaction force (VGRF) first exceeds a specific threshold.

[FIGURE:1]

During the "one leg standing with eyes open" test, the stability of the athlete's postural control is quantified by the displacement and velocity of the COP. These metrics provide an objective measure of the sensory-motor system's ability to maintain the body's center of mass over its base of support. Smaller values in the ellipse area and the mean velocity of COP movement generally indicate superior postural stability and more effective neuromuscular control.

10 N

2. Kinematic and Kinetic Parameters

2.1 Range of Motion (ROM)

The range of motion (ROM) is defined as the angular displacement of the three major joints of the lower limbs (hip, knee, and ankle) from the moment of initial contact to the point of maximum flexion during the landing phase.

2.2 Stability Index

The stability index is calculated using the ground reaction force (GRF) data collected during the first 3 seconds following initial ground contact. This index serves as a quantitative measure of the subject's postural control and dynamic stability during the landing transition.

10 N

The stability indices can be categorized into the anteroposterior stability index (APSI), the mediolateral stability index (MLSI), and the vertical stability index (VSI).

K s = ∑ （ 0 - F a ） 2 N ÷ W （ 6 ）

K t = ∑ （ 0 - F m ） 2 N ÷ W （ 7 ）

$W-F$ represents the antero-posterior stability index; $M-L$ represents the medio-lateral stability index; $V$ represents the vertical stability index; $F_x, F_y, F_z$ represent the ground reaction forces in the antero-posterior, medio-lateral, and vertical directions, respectively; $n$ represents the number of sampling points; and $BW$ represents the body weight.

[FIGURE:1] illustrates the variation curves of ground reaction forces for a specific athlete during a single-leg landing. It can be observed that following the impact at the moment of landing, the forces in all three directions exhibit significant fluctuations, reflecting the buffering and stabilization adjustment process of the lower limbs in response to the impact.

Note: In the antero-posterior direction, positive values represent a forward direction, while negative values represent a backward direction. In the medio-lateral direction, positive values represent a rightward direction, while negative values represent a leftward direction. In the vertical direction, positive values represent an upward direction.

Ground reaction force of an athlete during single-leg landing: antero-posterior ground reaction force (APGRF); medio-lateral ground reaction force (MLGRF).

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force MLGRF

3 Changes in APGRF

MLGRF and VGRF of an athlete landing on one leg. The peak vertical ground reaction force (VGRF) and the time to reach peak VGRF were recorded during the single-leg landing. The peak VGRF was normalized and expressed as a percentage of body weight (%BW). The loading rate was calculated using the formula: $\text{Loading Rate} = \frac{VGRF_{peak}}{\Delta t}$, where $VGRF_{peak}$ is the peak vertical ground reaction force and $\Delta t$ is the time required to reach that peak. The absolute symmetry index (ASI) was calculated as: $ASI = \frac{|X_L - X_R|}{0.5 \times (X_L + X_R)} \times 100\%$, where $X_L$ and $X_R$ represent the peak VGRF values for the dominant and non-dominant legs, respectively. An $ASI = 0$ indicates perfect symmetry between the lower limbs, while $ASI \leq 10\%$ suggests that the lower limbs are relatively symmetrical, and $ASI > 10\%$ indicates asymmetry. Regarding the results of the dynamic balance test and the kinematic characteristics of single-leg landing, there were no significant differences in joint angles at the instant of initial contact between the dominant and non-dominant legs.

Statistical analysis was performed using SPSS 26.0 software. The Shapiro-Wilk test was employed to verify the normality of the data distribution. For data following a normal distribution, paired t-tests were used to analyze the testing indicators; for data that did not follow a normal distribution, non-parametric tests were applied. The significance level for all tests was set at $\alpha = 0.05$.

2 结

Results of Static Balance and Joint Kinematics

In the static balance performance tests, no significant differences were observed between the dominant and non-dominant legs across all measured indices. [TABLE:1] presents the comparison of Center of Pressure (COP) indices during single-legged balanced standing between the non-dominant and dominant legs ($30.07 \pm 4.06$ vs. $31.09 \pm 5.41$; $74.52 \pm 9.39$ vs. $75.05 \pm 10.64$; $29.61 \pm 6.83$ vs. $30.07 \pm 6.19$; $68.35 \pm 8.29$ vs. $66.25 \pm 8.84$; $44.29 \pm 7.66$ vs. $44.19 \pm 8.76$; $57.35 \pm 6.35$ vs. $65.23 \pm 8.69$; $44.37 \pm 8.19$ vs. $47.03 \pm 7.09$; $70.24 \pm 6.35$ vs. $72.05 \pm 8.06$; $10.65 \pm 2.23$ vs. $10.41 \pm 2.55$; $15.62 \pm 5.3$ vs. $14.3 \pm 3.9$).

Regarding joint range of motion, significant differences were observed between the limbs. In the sagittal plane, the non-dominant leg exhibited significantly greater range of motion at the knee and ankle joints compared to the dominant leg. Conversely, in the frontal plane, the knee joint range of motion of the dominant leg was significantly greater than that of the non-dominant leg. [TABLE:2] provides a detailed comparison of joint angles at the moment of initial ground contact (IC) between the non-dominant and dominant legs (Hip: $-20.23 \pm 5.6$ vs. $-22.21 \pm 4.5$; Knee: $-0.82 \pm 2.3$ vs. $-1.1 \pm 3.2$; Ankle: $4.35 \pm 5.27$ vs. $3.62 \pm 4.52$; and subsequent kinematic data: $19.52 \pm 4.63$ vs. $18.32 \pm 5.39$; $-0.75 \pm 2.62$ vs. $-1.12 \pm 2.93$; $-3.41 \pm 6.81$ vs. $-2.6 \pm 5.9$; $33.52 \pm 11.45$ vs. $30.68 \pm 10.38$; $-7.61 \pm 3.92$ vs. $-6.92 \pm 3.85$; $-3.93 \pm 8.69$ vs. $-4.31 \pm 7.29$).

Dynamic Characteristics and Stability of Single-Leg Landing

The analysis of kinetic characteristics during the landing cushioning phase revealed specific patterns between the limbs. While some kinetic variables showed no significant differences between the non-dominant and dominant legs, others exhibited statistically significant variances, as detailed in [TABLE:18]. [TABLE:3] further compares the dynamic characteristic indices of single-leg landing ($2.12 \pm 0.21$ vs. $2.31 \pm 0.31$; $96.36 \pm 7.42$ vs. $89.55 \pm 7.66$; $62.64 \pm 9.32$ vs. $69.18 \pm 7.33$).

In terms of single-leg landing stability, the dynamic balance tests indicated that the stability indices for the non-dominant leg were significantly lower than those of the dominant leg. These findings, illustrated in the comparison between the non-dominant and dominant legs, suggest that the non-dominant limb may possess different compensatory strategies or inherent stability characteristics during high-impact dynamic tasks compared to the dominant limb.

3 讨论与分析

In this study, the dominant and non-dominant legs were determined based on the leg preferred for kicking a soccer ball or the leg capable of kicking the ball further. This classification method has been widely utilized across various sports disciplines, including soccer, freestyle skiing, and competitive aerobics, rather than being restricted to the specific sport practiced by the athletes.

Consequently, the present study adopted this established method to identify the dominant leg of volleyball players. The findings revealed that during static balance testing with eyes open, there were no significant differences in balance performance between the dominant and non-dominant legs. However, with eyes closed, the dominant leg exhibited significantly superior balance stability. This suggests that vision plays a fundamental role in postural control. In contrast, dynamic balance tests indicated that the non-dominant leg possessed greater stability and recovery capacity across various directions. This suggests that the non-dominant leg may have better biomechanical adaptability and neuromuscular control during landings, particularly under the demands of high-intensity exercise.

Static Balance Capacity

In volleyball, proficient static balance allows athletes to transition smoothly from a stationary state to dynamic movement. This study demonstrates that the performance discrepancies observed between eyes-open and eyes-closed conditions highlight the critical role of the visual system in maintaining equilibrium.

Research by KOZINC indicates that balance control involves the integration of multiple systems: the neuromuscular system regulates body posture; the vestibular and proprioceptive systems provide a sense of body position; and the visual system provides spatial orientation. Among these, vision is paramount for postural control. When other sensory inputs are compromised, visual compensation plays a vital role. Data from eyes-closed testing further suggest that the dominant and non-dominant legs exhibit different postural control capabilities in the anteroposterior direction.

Previous research has proposed that when physical balance is disturbed, a dynamic inhibition system composed of muscles and proprioception helps maintain stability. Studies on muscle strength have shown that the muscular strength of the dominant leg is typically greater than that of the non-dominant leg. Because volleyball players frequently perform anteroposterior movements and jumps during competition and training, the dominant leg often bears a higher load, which promotes...

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Further development of the muscles enhances balance control. In daily training, athletes should focus on strengthening the non-dominant leg to compensate for the impact of missing visual information on balance, thereby improving stability and reactivity in complex competitive environments.

Regarding dynamic balance, jump-landing in volleyball requires superior lower-limb stability. Particularly during the landing process after spiking or blocking, athletes must rapidly recover balance and buffer the impact. Single-leg landing is a common method for simulating volleyball landings and is frequently used in laboratory testing due to its high complexity. During testing, an athlete's control over their center of gravity (COG) upon landing directly reflects their risk of injury.

The deceleration capacity of the body's COG was measured in various directions. The data indicate that the stability of the non-dominant leg across all directions is superior to that of the dominant leg, demonstrating its biomechanical adaptability during the landing process. Especially in high-intensity sports, the non-dominant leg can control landings more effectively through training and adaptation. Simultaneously, research by Zahradnik found that during unilateral jump-landings, the knee and ankle joints of the dominant leg exhibit higher oscillation frequencies, showing clear lateralization.

Further analysis revealed that during the initial phase of landing, there are no significant differences between the dominant and non-dominant legs in three-dimensional directions, suggesting that athletes employ similar landing strategies at this stage. Lateralization primarily emerges during the subsequent buffering phase. By comparing the joint range of motion (ROM) of both legs in the sagittal plane, it was found that the non-dominant leg exhibits greater knee and ankle ROM during the buffering process. Research indicates that a "soft landing" is an effective strategy for reducing the risk of sports injuries, and the non-dominant leg carries a lower risk of injury during landing.

This serves as a measure of the athlete's ability to absorb ground reaction forces and is an important indicator for evaluating landing buffer patterns. The study found that the dominant leg's performance suggests that the bilateral lower limbs fail to bear impact forces equitably during long-term training.

These factors are closely related. Although there were no significant differences between the legs in certain metrics, the response time of the dominant leg was significantly shorter than that of the non-dominant leg, indicating a faster reaction to landing impact. Based on the kinematic data, it is hypothesized that the dominant and non-dominant legs adopt different strategies upon landing. The dominant leg relies primarily on rigid tissues (such as ligaments and joints) for buffering; while this allows for a rapid landing, it may also lead to injuries related to excessive impact, such as ligament damage. In contrast, the non-dominant leg distributes impact forces in a more coordinated manner, particularly through the muscle groups of the hip and knee joints. Research shows that differences in the buffering capacity and balance of lower limb joints reflect variations in neuromuscular control. The nervous system helps athletes effectively absorb impact and maintain balance by regulating muscle activity. When landing on the non-dominant leg, the nervous system optimizes control strategies to ensure coordinated work among relevant muscle groups, thereby dispersing ground reaction forces and reducing stress on joints and ligaments.

In comparison, the neuromuscular control of the dominant leg may be less flexible, particularly when facing significant impacts. Furthermore, differences in kinematic indicators are reflected not only in the sagittal plane but also in the frontal plane. The study found that the knee valgus/varus angles of the dominant leg during landing were significantly greater than those of the non-dominant leg. Knee instability is a risk factor for anterior cruciate ligament (ACL) injuries, especially when athletes need to adapt quickly to complex motor tasks. When facing high impact, the dominant leg fails to buffer effectively through the ankle, knee, and hip in the sagittal plane; instead, it overcompensates by increasing the joint ROM in the frontal plane. This compensatory mechanism may lead to excessive stretching of ligaments such as the ACL, thereby increasing injury risk. Based on the results of this study, it can be inferred that the higher stability of the non-dominant leg is closely related to its more efficient muscle synergy patterns and neural control strategies. By activating earlier and working more coordinately, the non-dominant leg can better distribute impact forces and reduce landing loads. Future electromyography (EMG) studies will help provide a more intuitive understanding of how the non-dominant leg coordinates muscle groups to reduce impact loads, providing stronger data support for lateralization and injury prevention in volleyball players.

Limitations of this study include: the lack of surface electromyography (sEMG) data in the test results, which prevents a more intuitive and accurate understanding of the lateralization of static and dynamic balance in volleyball players from a neuromuscular control perspective; and the fact that the dynamic balance tests only investigated stability related to forward jump-landings. Although this may be the most common scenario in actual competition, it is not the only method of single-leg landing. Subsequent studies should test multiple jump-landing directions, such as lateral and diagonal. Additionally, physical and mental fatigue also affect the performance of the dominant and non-dominant legs in static and dynamic balance tasks, which in turn influences lateralization results; these factors should be considered in future research.

4 结

Volleyball players exhibit a certain degree of lateralization in both static and dynamic balance capabilities. Regarding static balance, the balance performance of both legs is similar when the eyes are open. However, in the eyes-closed state, the dominant leg demonstrates superior static balance in the sagittal plane compared to the non-dominant leg, with the non-dominant leg relying more heavily on visual compensation. In terms of dynamic balance, the non-dominant leg outperforms the dominant leg, showing a clear lateralization effect. Consequently, future training programs should focus on enhancing the eyes-closed static balance of the non-dominant leg and the dynamic balance of the dominant leg to improve athletic performance and reduce the risk of injury.

Liang Zhiqiang, Jiang Yong, Jiao Fujia, et al. Effect of targeted modulation of the anterior tibialis muscle via transcranial direct current stimulation on static balance [J]. Chinese Journal of Applied Mechanics.

Liu Tao, Yang Yongtai. Correlation between plantar pressure distribution in different standing postures and structural characteristics of the foot arch [J]. Journal of Medical Biomechanics.

tributions and arch structural features in different standing positions [ J ] . Journal of medical biomechanics ， 2023 ， 38 （ 6 ）： 1093-1099 （ in

Correlation Analysis Between Balance Function and Cognitive Function in Volleyball Players of Different Levels

Introduction

The relationship between physical performance and cognitive capabilities remains a critical area of inquiry in sports science. Specifically, the interplay between balance control and cognitive processing is essential for high-level athletic performance. This study investigates the correlation between balance function and cognitive function among volleyball players of varying skill levels, aiming to elucidate how these two domains interact within the context of elite sports.

Literature Review

Previous research has highlighted the importance of specialized physical attributes in volleyball. For instance, Wang Junsheng, Rong Xiangjiang, and Yin Jun et al. conducted a correlation analysis between balance function and cognitive function in volleyball players, suggesting that higher-level athletes may exhibit distinct patterns of neural integration between motor control and cognitive tasks. Furthermore, the impact of physical imbalances on performance cannot be overlooked. Bishop, Turner, and Read provided a systematic review of the effects of inter-limb asymmetries on physical and sports performance, noting that such asymmetries can significantly influence an athlete's overall efficiency and injury risk.

In addition to balance, the technical execution of specific movements is vital. Li Xuhong, Fan Nianchun, and Han Bin et al. explored the characteristics of landing techniques in volleyball players, emphasizing that the biomechanical efficiency of landing is often tied to the athlete's proprioceptive feedback and cognitive anticipation.

Methodology and Objectives

The primary objective of this study is to assess whether a significant correlation exists between balance stability and cognitive performance metrics (such as reaction time, spatial awareness, and executive function) across different competitive tiers of volleyball players. By comparing elite athletes with sub-elite or amateur counterparts, we aim to identify whether specialized training leads to a more robust coupling of physical and mental functions.

[TABLE:1]

Discussion

The integration of motor and cognitive functions is particularly relevant in fast-paced sports like volleyball, where players must maintain postural stability while simultaneously processing complex visual information and making split-second decisions. Our findings suggest that balance function is not merely a peripheral motor skill but is deeply intertwined with central cognitive processes. This aligns with contemporary theories of embodied cognition, which posit that motor actions and cognitive states are mutually influential.

[FIGURE:1]

Conclusion

Understanding the correlation between balance and cognitive function provides valuable insights for the development of training protocols. By incorporating cognitive challenges into balance training—and vice versa—coaches and sports rehabilitators can better prepare volleyball players for the multifaceted demands of high-level competition.

landing techniques of volleyball players [ J ] . Chinese journal of

Comparative Analysis of Biomechanical Parameters Between Dominant and Non-Dominant Limbs During Landing in Freestyle Skiers

Introduction

In the field of sports medicine, understanding the neuromuscular control and biomechanical demands of landing is critical for injury prevention and performance optimization. Research by Leporace, Pereira, Nadal, et al. has highlighted significant differences in the time-frequency representation of lower limb myoelectric activity when comparing single-leg and double-leg landings in male athletes. Building upon these foundations, this study focuses specifically on freestyle skiers to examine the mechanical asymmetries between the dominant and non-dominant limbs during the landing phase.

Methodology and Comparative Analysis

The landing phase in freestyle skiing involves complex energy dissipation and stabilization strategies. To investigate these dynamics, we conducted a comparative analysis of mechanical parameters between the dominant and non-dominant legs. This study utilizes methodologies similar to those established in electromyography and kinesiology research to capture the nuances of force distribution and muscle activation patterns.

[TABLE:1]

The assessment focused on several key biomechanical indicators, including ground reaction forces (GRF), joint kinematics, and the timing of peak impact. By analyzing these variables, we can identify whether freestyle skiers exhibit significant lateral dominance that might predispose them to specific injury patterns, such as anterior cruciate ligament (ACL) tears or chronic joint degeneration.

Results and Discussion

Our findings indicate that while freestyle skiers aim for symmetrical landings to maximize stability and scoring potential, measurable differences persist between the dominant and non-dominant limbs. These differences are often reflected in the rate of force development and the stiffness of the lower limb joints upon impact.

[FIGURE:1]

As noted in the work of Cui Xinze and Wang Xin regarding biomechanical parameters in freestyle skiers, the dominant leg often exhibits a more proactive neuromuscular recruitment strategy. This is consistent with the findings of Leporace et al., who observed distinct time-frequency characteristics in myoelectric signals during different landing tasks. The non-dominant leg, conversely, may show a slight delay in peak activation or a different strategy for absorbing impact energy, which could be a critical factor in the mechanical loading of the knee and ankle joints.

Conclusion

The comparative analysis of dominant and non-dominant limbs in freestyle skiers reveals that limb asymmetry is a factor that must be addressed in both training and rehabilitative contexts. By understanding the specific mechanical parameters—such as peak force and muscle activation timing—coaches and sports medicine professionals can develop targeted interventions to balance the loading profiles of athletes

CUI Xinze ， WANG Xin. Comparison of mechanical parameters of

dominant and non-dominant legs of freestyle skiers when they fall [ J ] . Journal of medical biomechanics ， 2021 ， 36 （ S1 ）： 413-414 （ in

Sadeghi H, Allard P, Prince F, et al. Symmetry and limb dominance in able-bodied gait: a review. Gait & Posture.

Brown C N, Rosen A B, et al. Individuals with both perceived ankle instability and mechanical laxity demonstrate dynamic postural stability deficits. Clinical Biomechanics.

Mao Xiaokun, Zhang Qiuxia, Wang Guodong, et al. Biomechanical laterality effect between the dominant and non-dominant limbs during the stance phase of running. Journal of Capital Institute of Physical Education.

Biomechanical Laterality Effect Between the Dominant and Non-Dominant Limbs

The study of symmetry and limb dominance is a critical aspect of understanding human locomotion. As established in the literature, particularly by Sadeghi et al. in their comprehensive review of able-bodied gait, the functional roles of the dominant and non-dominant limbs often differ during movement. While symmetry is frequently assumed in clinical and biomechanical models, empirical evidence suggests that subtle asymmetries exist even in healthy populations.

Further research into joint stability, such as the work by Brown and Rosen, highlights how physiological factors like mechanical laxity and perceived instability can exacerbate these asymmetries, leading to measurable deficits in dynamic postural stability. These findings underscore the importance of distinguishing between the two limbs when assessing injury risk or athletic performance.

In the specific context of running, Mao Xiaokun and colleagues investigated the biomechanical laterality effects during the stance phase. Their research focuses on how the dominant and non-dominant limbs manage load and generate force differently. Understanding these laterality effects is essential for developing targeted rehabilitation protocols and optimizing training loads to prevent unilateral overuse injuries.

during running support phase [ J ] . Journal of Capital University of

Physical Education and Sports in Chinese PROMSRI A LONGO A HAID T et al. Leg dominance as a risk factor for Lower-Limb injuries in downhill skiers-a pilot study into

possible mechanisms [ J ] . International journal of environmental re-

Biomechanical Research on the Laterality Effect Between Dominant and Non-dominant Sides During the Front Roundhouse Kick in Taekwondo Athletes

Authors: LIU Lin, MA Yong, LIN Shijie, et al.
Source: Journal of Wuhan Institute of Physical Education

Abstract

This study investigates the biomechanical differences between the dominant and non-dominant sides of taekwondo athletes performing the front roundhouse kick (front cross-kick). By analyzing kinematic and kinetic data, the research aims to identify the specific characteristics of lateral asymmetry in elite athletes. The findings provide a theoretical basis for optimizing technical training, improving performance consistency, and reducing the risk of sports injuries associated with bilateral imbalances.

1. Introduction

In the modern competitive landscape of taekwondo, the ability to execute techniques effectively with both legs is a critical factor for success. The front roundhouse kick is one of the most frequently utilized and scoring-efficient techniques in competition. However, most athletes exhibit a degree of "laterality" or "limb dominance," where one side performs with greater precision, power, or speed than the other. Understanding the biomechanical roots of this asymmetry is essential for developing targeted training interventions.

2. Methods

2.1 Participants

The study recruited high-level taekwondo athletes as subjects. All participants were free of lower-limb injuries for at least six months prior to testing and were proficient in performing the front roundhouse kick with both their dominant and non-dominant legs.

2.2 Data Collection

Biomechanical data were collected using a synchronized system including a high-speed motion capture system and force plates.
- Kinematics: Reflective markers were placed on key anatomical landmarks to track joint angles, angular velocities, and linear velocities of the kicking leg.
- Kinetics: Force plates were used to measure the ground reaction forces (GRF) of the supporting leg during the initiation and execution phases of the kick.

[TABLE:1]

2.3 Experimental Procedure

Participants performed the front roundhouse kick at maximum effort toward a target. Each athlete completed multiple successful trials for both the dominant and non-dominant sides, with adequate rest intervals to prevent fatigue.

3. Results

3.1 Kinematic Analysis

The results indicate significant differences in the maximum velocity of the foot at the moment of impact. The dominant side generally exhibited a higher peak angular velocity in the hip and knee joints compared to the

kick in taekwondo [ J ] . Journal of Wuhan Sports University ， 2023 ，

KOZINC Ž, ŠARABON N. The effects of leg preference and leg dominance on static and dynamic balance performance in highly-trained tennis players. PLoS One, 2021, 16(11): e0259854.

ZHANG Meizhen, GUO Hao, LIU Hui, et al. Effect of different fatigue protocols on trunk and lower extremity kinematics for collegiate soccer players. China Sport Science and Technology, 2021, 57(10): 36-43.

58 （ 8 ）： 32-40 （ in Chinese ） . [ 15 ] HOUJ Q ， NITSCHE M A ， YI L Y ， et al. Effects of transcranial di-

Biomechanical Research on Landing Laterality and Stability

Introduction

The study of postural stability and landing mechanics is critical for understanding injury prevention and athletic performance. Recent research has explored various interventions and biomechanical factors, including the application of direct current stimulation over the primary motor cortex to improve postural stability in healthy young adults. Furthermore, specific athletic populations, such as competitive aerobics athletes, present unique biomechanical profiles during high-impact maneuvers.

Biomechanical Study of Laterality and Stability

Wang Lili, Bin Wan Pa W A M, Wang Yuxuan, et al. conducted a biomechanical study focusing on the laterality and stability of college competitive aerobics athletes during double-leg landings \cite{1}. Their research highlights how elite athletes manage impact forces and maintain equilibrium when performing complex technical movements. Understanding these patterns is essential for optimizing training protocols and reducing the risk of lower-extremity injuries in high-intensity sports.

[FIGURE:1]

Comparative Analysis of Dominant and Non-Dominant Limbs

The distinction between the dominant and non-dominant legs during landing tasks remains a central focus of sports biomechanics. Liu Hairui, Fu Weijie, Wu Xie, et al. investigated the biomechanical laterality of the dominant versus non-dominant leg during single-leg landings \cite{2}. Their findings suggest that asymmetries in force absorption and joint kinematics can significantly influence stability.

[TABLE:1]

Research indicates that these asymmetries are often more pronounced during single-leg tasks compared to double-leg landings. By quantifying the differences in peak ground reaction forces and joint angles between limbs, researchers can better identify potential "weak links" in an athlete's kinetic chain. This data is vital for developing targeted rehabilitation and conditioning programs aimed at achieving bilateral symmetry and improving overall postural control.

LIU Hairui ， FU Weijie ， WU Xie ， et al. Biomechanics research on

laterality effect between dominant and non-dominant leg during sin- gle leg landing . China sport science Chinese DEBIEN P B MANCINI M COIMBRA D R et al. Monitoring

training load ， recovery ， and performance of Brazilian professional

...volleyball players during a season. International Journal of Sports Physiology and Performance.

PAPPAS E, CARPES F P. Lower extremity kinematic asymmetry in male and female athletes performing jump-landing tasks. Journal of Science and Medicine in Sport.

WANG Wenwen, ZHANG Wanqin, LÜ Jiaojiao, et al. Effects of high-definition transcranial direct current stimulation on balance function, muscle strength, and proprioception in patients with chronic ankle instability. Chinese Journal of Rehabilitation Medicine.

Abstract

Chronic ankle instability (CAI) is a common musculoskeletal condition characterized by persistent symptoms, including a "giving way" sensation and recurrent sprains. This study investigates the therapeutic potential of high-definition transcranial direct current stimulation (HD-tDCS) in addressing the multifaceted deficits associated with CAI. Specifically, we examined the impact of this neuromodulatory intervention on balance function, muscle strength, and proprioception in an affected population.

Introduction

Chronic ankle instability often leads to long-term impairments in postural control and neuromuscular function. Traditional rehabilitation focuses on local physical therapy and strength training; however, recent evidence suggests that central nervous system reorganization plays a significant role in the persistence of CAI symptoms. High-definition transcranial direct current stimulation (HD-tDCS) offers a non-invasive method to modulate cortical excitability with higher spatial precision than conventional tDCS. By targeting the motor cortex, HD-tDCS may enhance the neural drive to the lower extremity muscles and improve sensorimotor integration.

Methods

The study recruited participants diagnosed with chronic ankle instability based on established clinical criteria. Participants were randomly assigned to receive either active HD-tDCS or a sham stimulation protocol. The intervention targeted the primary motor cortex (M1) area corresponding to the lower limb.

Assessment measures included:
- Balance Function: Evaluated using static and dynamic postural stability tests, such as the Star Excursion Balance Test (SEBT).
- Muscle Strength: Measured via isokinetic dynamometry to assess the peak torque of the ankle evertors and dorsiflexors.
- Proprioception: Assessed through joint position sense (JPS) testing to determine the accuracy of angle replication.

Results and Discussion

The

1190 应用力学学报

ic ankle instability [ J ] . Chinese journal of applied mechanics ，

FRANSZ D. P., HUURNINK A., DE BOODE V. A., et al. Time to stabilization in single leg drop jump landings: an examination of calculation methods and assessment of differences in sample rate, filter settings, and trial length on outcome values. Gait & Posture.

FU Guangliang, MENG Qinghua, BAO Chunyu. Differences in proprioceptive mechanics and the intervention effect of balance training in functional ankle instability. Chinese Journal of Applied Mechanics.

ZHANG Fan, WANG Zhuying, WU Zhijian, et al. Influence of ankle stability differences on landing buffer modes during side hops. China Sport Science and Technology.

YIN Ran. Study on the differential effects of take-off in three directions on lower limb muscles and joints during landing. Genomics and Applied Biology.

ZAHRADNIK D., JANDACKA D., UCHYTIL J., et al. Lower extremity mechanics during landing after a volleyball block as a risk factor for anterior cruciate ligament injury. Physical Therapy in Sport.

YU Yue, LIU Dongsen, RUAN Bin, et al. Advances in the therapeutic effects of balance training on chronic ankle instability. Chinese Journal of Rehabilitation Theory and Practice.

ing for chronic ankle instability ： a systematic review [ J ] . Chinese

Study on the Application of Balance Training in the Prevention and Rehabilitation of Lower Limb Sports Injuries

Wei Zhifeng, Wang Zipu, Du Chengrun, et al.
Journal of Rehabilitation Theory and Practice / China Sport Science and Technology

Abstract

This study explores the critical role of balance training in both the prevention of and recovery from lower limb sports injuries. By synthesizing current clinical evidence and biomechanical principles, the research evaluates how systematic balance interventions enhance neuromuscular control, joint stability, and proprioception. The findings suggest that integrating balance exercises into athletic training regimens significantly reduces the incidence of common injuries, such as ankle sprains and anterior cruciate ligament (ACL) tears, while accelerating the functional recovery of injured athletes.

Analysis of Drop Jump Performance in High-Level Sprinters: A Lower-Limb Joint Biomechanical Perspective

Zang Yu, Xu Yilin, Xiang Xiaoyan, et al.
Sports Science

Introduction

The drop jump (DJ) is a fundamental plyometric exercise widely used to assess and develop the stretch-shortening cycle (SSC) capacity in elite athletes. For high-level sprinters, the ability to rapidly transition from an eccentric contraction to a concentric contraction is paramount for achieving explosive ground reaction forces and maintaining high running velocities. This study investigates the biomechanical characteristics of the lower limb joints during the drop jump to identify the specific kinetic and kinematic factors that distinguish elite performance.

Methodology

The study utilized a high-speed infrared motion capture system and synchronized force plates to record the performance of high-level sprinters. Biomechanical variables, including joint angles, moments, and power outputs for the hip, knee, and ankle, were calculated using inverse dynamics.

[TABLE:1]

Results and Discussion

The analysis reveals that high-level sprinters exhibit distinct joint coordination patterns compared to sub-elite athletes. Specifically, the ankle joint plays a dominant role in energy absorption and generation during the contact phase, characterized by high stiffness and rapid force development.

Joint Kinematics and Kinetics

During the landing phase of the drop jump, the peak vertical ground reaction force ($F_{max}$) and the reactive strength index (RSI) serve as primary indicators of explosive performance. The relationship between joint moment ($M$) and angular velocity ($\omega$) can be expressed through the instantaneous power:
$$P = M \cdot \omega$$
Our data indicate that elite sprinters maintain a more "stiff" landing strategy,

biomechanics perspective [ J ] . China sport science ， 2023 ， 43 （ 1 ）：

in Chinese LAUGHLIN W A WEINHANDL J T KERNOZEK T W et al. The

effects of single-leg landing technique on ACL loading [ J ] . Journal

of biomechanics ， 2011 ， 44 （ 10 ）： 1845-1851. [ 30 ] MUNSCH A E ， EVANS-PICKETT A ， DAVIS-WILSON H ， et al.

Effects of Dual Tasks with Different Types and Loads on Dynamic Postural Control in Healthy Adults

Introduction

Postural control is a fundamental requirement for performing daily activities and maintaining physical stability. In real-world scenarios, individuals rarely perform postural tasks in isolation; instead, they often engage in concurrent cognitive or motor activities, a phenomenon known as dual-tasking. Research has shown that performing a secondary task can compete for attentional resources, potentially compromising postural stability. This is particularly relevant in the context of injury prevention and rehabilitation, such as following anterior cruciate ligament (ACL) reconstruction, where limb underloading during walking can lead to reduced dynamic knee joint contact forces, as noted in recent sports medicine literature. Understanding how different types and loads of dual tasks affect dynamic postural control is essential for developing effective training and assessment protocols.

Methods

This study investigated the impact of various dual-task conditions on the dynamic postural control of healthy adults. Participants were required to maintain balance while simultaneously performing secondary tasks that varied in both type (e.g., cognitive vs. motor) and cognitive load (e.g., simple vs. complex). Dynamic postural control was assessed using standardized balance metrics, including center of pressure (COP) excursions and stability indices.

[TABLE:1]

The experimental design categorized dual tasks into several levels of difficulty to observe the threshold at which postural performance begins to degrade. Cognitive tasks included mental arithmetic and memory recall, while motor tasks involved manual manipulations. By systematically varying these factors, we aimed to identify the specific conditions under which dynamic stability is most significantly challenged.

Results

The results indicate that both the type and the load of the secondary task significantly influence dynamic postural control. Specifically, cognitive tasks with high attentional demands led to increased COP variability and a decrease in overall stability compared to single-task conditions. Interestingly, the interference effects were more pronounced in tasks requiring complex executive functions than in those involving simple motor repetitions.

[FIGURE:1]

Furthermore, the data revealed a non-linear relationship between task load and postural sway. While low-load dual tasks resulted in minimal changes to stability—and in some cases, even improved focus—high-load conditions consistently resulted in diminished postural performance. This suggests a "bottleneck" in central processing where the competition for neural resources between the primary postural task and the secondary cognitive task becomes critical.

Discussion

The findings of this study highlight the complexity of the human postural control system when operating under dual-task constraints. The observed decrease in stability during

Journal of medical biomechanics ， 2023 ， 38 （ 4 ）： 791- 796 （ in Chi-