Association between self-perceived error during the modified star excursion balance test and chronic low back pain history in male collegiate baseball players: an exploratory cross-sectional study

Abstract

[Purpose] This exploratory study examined the association between self-perceived error during a dynamic balance task and history of chronic low back pain in male collegiate baseball players. [Participants and Methods] Seventy-four male collegiate baseball field players participated. History of chronic low back pain was classified as low back pain lasting three months or longer. During the Modified Star Excursion Balance Test, predicted and actual reach distances were measured. Self-perceived error was calculated as the predicted value minus the actual value, normalized to lower limb length. Positive and negative values indicated overestimation and underestimation, respectively. [Results] Twenty-seven participants were classified into the overestimation group and 47 into the underestimation group. History of chronic low back pain was observed in 3 participants in the overestimation group and 15 in the underestimation group. Self-perceived error was associated with history of chronic low back pain. [Conclusion] Self-perceived error during a dynamic balance task was associated with history of chronic low back pain in male collegiate baseball players. This exploratory finding suggests that the difference between predicted and actual performance may provide supplementary information in physical therapy assessment.

INTRODUCTION

Baseball involves repetitive rotational movements, such as batting and pitching, as well as asymmetrical movements, which may place mechanical stress on the low back. Low back pain can affect athletic participation and performance in baseball players, and continuous and comprehensive assessment of physical function is important for athletes with a history of chronic low back pain^{1, 2)}. Impairments in trunk function, flexibility, and balance have been reported in individuals with chronic low back pain^3,4,5,6), and these are important assessment items in physical therapy evaluation.

In physical function assessment, not only actual performance but also self-perception of physical capability, that is, how far an individual predicts they can move, may provide supplementary information. Self-perceived physical capability has been reported to be associated with previous injury in collegiate athletes⁷⁾. However, most previous studies have relied on questionnaires or self-reported measures. Therefore, few studies have examined the discrepancy between predicted and actual performance during motor tasks. In particular, limited evidence is available regarding the discrepancy between predicted and actual performance during dynamic balance tasks in young athletes with a history of chronic low back pain.

The Modified Star Excursion Balance Test (mSEBT) is used to assess dynamic balance ability^{8, 9)}. In this study, in addition to the actual reach distance on the mSEBT, we recorded the predicted reach distance before task performance and operationally defined the difference between the predicted and actual values as self-perceived error during the dynamic balance task. The purpose of this study was to examine the association between self-perceived error during the mSEBT and history of chronic low back pain in male collegiate baseball players.

PARTICIPANTS AND METHODS

This was an exploratory cross-sectional study of male collegiate baseball players. The participants were 74 male field players from the collegiate baseball team at University A, with a mean age of 19.8 ± 1.4 years, mean height of 172.3 ± 4.6 cm, and mean body mass of 72.6 ± 8.0 kg. Pitchers were excluded because the physical demands of pitching differ from those of field players. All participants were participating in team practice at the time of measurement, and none had missed practice because of pain. The participants were informed of the study purpose, measurement procedures, and protection of personal information, and written informed consent was obtained. This study was approved by the Institutional Review Board of the affiliated institution (Approval No. 05P24025).

History of chronic low back pain was confirmed through a face-to-face interview conducted by the researchers. The interview assessed the duration of low back pain, symptom location, and current participation in practice. In this study, participants with a history of low back pain lasting three months or longer were classified as having a history of chronic low back pain¹⁰⁾. This classification was based on history of low back pain and did not include assessment of current pain intensity, functional disability, or psychological factors.

The mSEBT was used as the dynamic balance task. The Star Excursion Balance Test and its modified versions are used to assess dynamic balance ability^{8, 9)}. Participants stood on one leg and reached in three directions (anterior, posterolateral, and posteromedial) with the contralateral lower limb. Before the actual trials, participants were asked to indicate the farthest position they expected to reach in each direction, and this distance was recorded as the predicted reach distance. The predicted reach distance was recorded before performing any measured reach trial. Participants were shown the reach directions on the floor, but no practice reach trial was conducted before recording the predicted reach distance. The actual reach distance was not verbally fed back to the participants during the measurement. Subsequently, the actual reach distance was measured in each direction. Measurements were performed on both the left and right sides, and the maximum value from two trials in each direction was used for analysis.

For both predicted and actual reach distances, the sum of the three directions was calculated for each side, and the average of the left and right values was used as the representative value. Lower limb length was measured as the distance from the anterior superior iliac spine to the medial malleolus. Self-perceived error during the dynamic balance task was calculated using the following formula:

Self-perceived error (%)=[(predicted reach distance − actual reach distance) / lower limb length] ×100

Positive values indicated overestimation of actual performance, whereas negative values indicated underestimation.

SPSS Statistics version 27.0 was used for statistical analysis. First, participants were classified into overestimation and underestimation groups based on the sign of self-perceived error, and the association with history of chronic low back pain was examined using the χ² test. Next, binary logistic regression analysis was performed, with history of chronic low back pain as the dependent variable and self-perceived error as the independent variable. An adjusted model was then created by including lumbar flexion and extension ranges of motion as covariates. This study was exploratory in nature, and no prior sample size calculation was performed. The significance level was set at 5%.

RESULTS

Participant characteristics are shown in Table 1. Based on self-perceived error, 27 participants were classified into the overestimation group and 47 into the underestimation group. In the overestimation group, 24 participants had no history of chronic low back pain and 3 had a history of chronic low back pain. In the underestimation group, 32 participants had no history of chronic low back pain and 15 had a history of chronic low back pain. Self-perceived error classification was associated with history of chronic low back pain (χ² test, p=0.045). The results of this analysis are shown in Table 2.

Table 1. Participant characteristics.

Variable	Total (n=74)
Age (years)	19.8 ± 1.4
Height (cm)	172.3 ± 4.6
Body mass (kg)	72.6 ± 8.0
Body mass index (kg/m2)	24.4 ± 2.1
Modified Star Excursion Balance Test (%)	73.7 ± 9.3
History of chronic low back pain, n	18

Values are presented as mean ± standard deviation or number. History of chronic low back pain was defined as low back pain lasting ≥3 months.

Table 2. Association between self-perceived error classification and history of chronic low back pain.

Self-perceived error classification	No history of chronic low back pain	History of chronic low back pain	Total
Overestimation	24	3	27
Underestimation	32	15	47
Total	56	18	74

Self-perceived error (%)=[(predicted reach distance − actual reach distance) / lower limb length] ×100. Positive values indicate overestimation, and negative values indicate underestimation.

In the binary logistic regression analysis, self-perceived error was associated with history of chronic low back pain (odds ratio=0.926, 95% confidence interval=0.871–0.984, p=0.014). This association remained after adjustment for lumbar flexion and extension ranges of motion (adjusted odds ratio=0.919, 95% confidence interval=0.860–0.982, p=0.012). The results of the logistic regression analysis are shown in Table 3.

Table 3. Logistic regression analysis for history of chronic low back pain.

Logistic regression analysis	OR (95% CI)
Univariable model	0.926 (0.871–0.984)*
Adjusted model	0.919 (0.860–0.982)*

*p<0.05. Adjusted model included lumbar flexion and extension ranges of motion as covariates. OR, odds ratio; CI, confidence interval.

DISCUSSION

This exploratory cross-sectional study examined the association between self-perceived error during the mSEBT and history of chronic low back pain in male collegiate baseball players. Players who exhibited underestimation had a higher prevalence of history of chronic low back pain than those who exhibited overestimation. In addition, self-perceived error was associated with history of chronic low back pain even after adjustment for lumbar flexion and extension ranges of motion. These findings suggest that the discrepancy between predicted and actual reach distances may be considered supplementary information in the physical therapy assessment of male collegiate baseball players with history of chronic low back pain.

Impaired trunk function, flexibility, and balance ability have been reported in individuals with chronic low back pain^3,4,5,6). Lumbar active range of motion has also been reported as a clinical factor related to disability in individuals with chronic low back pain¹¹⁾. The Star Excursion Balance Test has also been used to detect reduced reach distance in individuals with chronic low back pain⁶⁾, and its performance has been reported to vary by sport in collegiate athletes¹²⁾. The distinctive feature of the present study is that it focused not only on actual reach distance during the mSEBT, but also on the discrepancy between predicted and actual reach distances. Therefore, this study does not clarify superiority or inferiority in dynamic balance ability, but instead explores self-perceived error during a dynamic balance task.

Self-perceived physical capability has been reported to be associated with previous injury in collegiate athletes⁷⁾. However, most previous studies have relied on questionnaires or self-reported measures, and few studies have examined the discrepancy between predicted and actual values during physical tasks. In this study, self-perceived error was operationally defined as the difference between predicted and actual reach distances during the mSEBT. This indicator is not an established clinical assessment scale, but an exploratory measure used in this study. Therefore, the results should not be interpreted as indicating that self-perceived error predicts history of chronic low back pain, but rather as suggesting an additional perspective for physical therapy assessment.

As this study used a cross-sectional design, the direction of the association between self-perceived error and history of chronic low back pain could not be determined. Underestimation of dynamic balance performance may have occurred because of previous low back pain experiences, such as pain-related fear, reduced confidence in movement, or decreased self-efficacy. Conversely, inaccurate perception of movement capability may reflect altered sensorimotor integration or body awareness, which could be related to vulnerability to low back pain. Therefore, the present findings should be interpreted as an exploratory association and not as evidence that self-perceived error is either a cause or consequence of chronic low back pain history.

Athletes who underestimated their reach ability had a higher proportion of history of chronic low back pain. This finding suggests that the discrepancy between predicted and actual reach distances may provide information different from actual reach performance alone. However, this study did not assess pain intensity, functional disability, psychological factors, proprioception, or sensory processing. Therefore, the mechanisms underlying why athletes with history of chronic low back pain tended to underestimate their dynamic balance ability cannot be determined. Although changes related to postural control, proprioceptive weighting, sense of effort, and lumbar joint position sense have been reported in individuals with chronic low back pain^13,14,15), these factors were not directly measured in this study and should be addressed in future research.

Caution is also needed regarding the classification of the history of chronic low back pain. Participants were classified as having a history of chronic low back pain based on whether they experienced low back pain lasting three months or longer. However, definitions of chronic low back pain are known to vary depending on study objectives and assessment methods¹⁰⁾. Additionally, the timing of the episode, recurrence status, current pain intensity, functional disability, and symptom severity were not assessed in detail. Therefore, the association between the extent of the previous low back pain episode to current motor control, sensorimotor integration, or perception of movement capability at the time of measurement remains unclear. This limitation may affect the reproducibility and clinical interpretation of the present findings. Accordingly, the results should be interpreted as an exploratory association with history of chronic low back pain, rather than as an association with current low back pain severity or current functional impairment.

This study has some limitations. First, because this was a cross-sectional study, a causal relationship between self-perceived error and history of chronic low back pain cannot be established. Second, the participants were limited to male collegiate baseball players from a single institution, which limits generalizability. Third, history of chronic low back pain was classified through a face-to-face interview and did not include detailed assessments of pain intensity, disability, or symptoms. Fourth, confounding factors such as training volume, fatigue, previous injury history, and psychological factors were not adequately adjusted for. Furthermore, this study did not examine the reproducibility of the prediction task or learning effects during the mSEBT. Because predicted reach distance may become closer to actual reach distance after repeated task exposure, future studies should examine the reliability, measurement error, and learning effect of self-perceived error before its clinical interpretation can be established.

In conclusion, self-perceived error during the mSEBT was associated with history of chronic low back pain in male collegiate baseball players. The discrepancy between predicted and actual reach distances may be considered a supplementary perspective in physical therapy assessment, although further validation is required.

Funding

This work was supported by JSPS KAKENHI Grant Number JP24K20570.

Conflict of interest

The authors declare no conflicts of interest.

Funding Statement

This work was supported by JSPS KAKENHI Grant Number JP24K20570.