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Association between lower back pain and lower extremity pain among young volleyball players: A cross-sectional study
Physical Therapy in Sport 43 (2020) 65e69
Contents lists available at ScienceDirect
Physical Therapy in Sport journal homepage: www.elsevier.com/ptsp
Original Research
Association between lower back pain and lower extremity pain among young volleyball players: A cross-sectional study Yutaka Yabe a, Yoshihiro Hagiwara a, b, *, Takuya Sekiguchi a, Haruki Momma b, Masahiro Tsuchiya c, Kenji Kanazawa a, Nobuyuki Itaya a, Shinichirou Yoshida a, Yasuhito Sogi a, Toshihisa Yano a, Takahiro Onoki a, Eiji Itoi a, Ryoichi Nagatomi b, d a
Department of Orthopaedic Surgery, Tohoku University School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan Department of Medicine and Science in Sports and Exercise, Tohoku University School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan Department of Nursing, Faculty of Health Science, Tohoku Fukushi University, 1-8-1 Kunimi, Aoba-ku, Sendai, 981-8522, Japan d Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 27 June 2019 Received in revised form 15 February 2020 Accepted 16 February 2020
Background: Lower back pain (LBP), as well as lower extremity injuries, are major problems among young volleyball players. Nevertheless, only few studies have focused on the relationship between lower extremity injuries and LBP. Objective: This study investigated the association between LBP and lower extremity pain, including knee and ankle pain, among young volleyball players. Design: Cross-sectional study. Setting: Amateur sports association. Participants: Elementary and middle school-aged athletes (6e15 years of age). Main outcome measures: LBP and lower extremity pain. Results: A total of 566 young volleyball players participated in this study. The point prevalence of LBP among young volleyball players was 9.5%. Using absence of lower extremity pain as a reference, the adjusted odds ratio (95% confidence interval) for LBP was 11.07 (5.64e21.71) in the presence of lower extremity pain. Conclusions: LBP is associated with Lower extremity pain among young volleyball players. Careful attention should be paid to lower extremity complaints to prevent and treat LBP among young volleyball players. © 2020 Elsevier Ltd. All rights reserved.
Keywords: Lower back pain School-aged athletes Lower extremity pain Volleyball
1. Introduction Volleyball is one of the most popular sports in the world, with 200 million players worldwide (Kilic, Maas, Verhagen, Zwerver, & Gouttebarge, 2017). Volleyball is considered to have a lower incidence of injuries than sports such as basketball, handball, or football that entail frequent tackles or contact with opponents (Bere, Kruczynski, Veintimilla, Hamu, & Bahr, 2015). Nevertheless, volleyball requires frequent jumping and sport-specific movements such as spiking, serving, and blocking, all of which put players at
* Corresponding author. Department of Orthopaedic Surgery, Tohoku University School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan. E-mail address: [email protected] (Y. Hagiwara). https://doi.org/10.1016/j.ptsp.2020.02.005 1466-853X/© 2020 Elsevier Ltd. All rights reserved.
risk for musculoskeletal injuries (Sarto, Grigoletto, Baggio, Paoli, & Marcolin, 2019). Whereas lower extremity injuries, including the knee and ankle, commonly occur among volleyball players (Bere et al., 2015), the lower back is the third most-frequent body part reported to incur injuries (Smith, Nyland, Caudill, Brosky, & Caborn, 2008). However, lower back injuries have not been studied extensively (Farahbakhsh, Rostami, et al., 2018). Currently, lower back pain (LBP) is reported as a common problem among young athletes as well as adults (Hangai et al., 2010). LBP leads to poor performance in young athletes and time loss participating in sports (Takemitsu, El Rassi, Woratanarat, & Shah, 2006). For these reasons, it is important to understand the factors related to LBP to prevent and treat LBP among young athletes. Factors, such as sex (Fett, Trompeter, & Platen, 2017), age (Shah, Cloke, Rushton, Shirley, & Deehan, 2014), body mass index
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Y. Yabe et al. / Physical Therapy in Sport 43 (2020) 65e69
(BMI) (Noormohammadpour et al., 2016), competition level (Fett et al., 2017), and intensity of training (Newlands, Reid, & Parmar, 2015) have previously been reported to be associated with LBP among athletes. Furthermore, the prevalence of LBP varies between different types of sports because each sport requires certain body movements and the load imposed on the lumbar spine is different among the various sports (Farahbakhsh, Akbari-Fakhrabadi, et al., 2018). Considering LBP among young volleyball players, dysfunction of the lower extremities due to pain can lead to LBP because motions in volleyball such as spiking, blocking, and serving, need coordinated movements of the lower extremities and lumbar spine. To prevent and treat LBP among young volleyball players, it is important to determine whether there is an association of lower extremity complaints with LBP. However, to the best of our knowledge, no reports have evaluated this association among volleyball players. Therefore, the purpose of this study was to determine the association between LBP and lower extremity pain, including knee and ankle pain, among young volleyball players. 2. Materials and methods 2.1. Participants A cross-sectional study was performed with elementary and middle school-aged athletes (6e15 years of age) belonging to an amateur sports association using a self-reported questionnaire for a comprehensive survey of their sports activities, lifestyles, and problems in sports. Many types of sports, including baseball, football, basketball, volleyball, and judo, were included in the association. The association possessed mailing address of registered athletes; a self-reported questionnaire and an informed consent form were mailed to all of them in October 2014 (n ¼ 25,469). All participants were asked to answer the questionnaire by themselves; however, parents were allowed to help younger participants. Among the registered athletes, 7333 consented to this study and responded to the questionnaire (response rate of 28.8%). Respondents who did not play volleyball (n ¼ 6646) or who played other sports together with volleyball (n ¼ 6) were excluded. The
respondents with missing data were excluded from the analysis (n ¼ 115) to yield a final sample size of 566 volleyball players (Fig. 1).
2.2. Lower back and lower extremity pain LBP and lower extremity pain were assessed by the following question, “Do you have pain in any parts of your body? If yes, please check the parts you have pain”. Body parts, including the head, lower back, and each joint, were illustrated by a drawing and multiple-choice answers were allowed. Participants who checked lower back, knee, or ankle were determined to have LBP, knee pain, or ankle pain, respectively. Further, the participants who had knee pain and/or ankle pain were defined to have lower extremity pain.
2.3. Covariates The covariates used in the analysis were sex, age, BMI (calculated using self-reported height and weight values), team level (recreation, local competition, prefectural competition, distinct competition, or national competition), number of days for training per week, number of hours for practice per day on weekdays and weekends, frequency of participation in games (never, seldom, sometimes, or often), and practice intensity (not hard or hard) because they were considered potential cofounding factors. The following continuous variables were divided into categories by the distribution according to previous reports (Yabe et al., 2017; Sekiguchi et al., 2018): number of days for training per week was categorized into two groups ( 3 and > 3 days per week); number of hours for practice per day on weekdays was placed into two groups ( 2 and > 2 h per day); and number of hours for practice per day on weekends was divided into two groups ( 3 and > 3 h per day). The following categorical variables were divided into groups according to the distribution: team level (low: “recreation” or “local competition”; high: “prefectural competition” or higher) and frequency of participation in games (sometimes or seldom: “never”, “seldom”, or “sometimes”; frequently: “often”).
Fig. 1. Flow chart of the study.
Y. Yabe et al. / Physical Therapy in Sport 43 (2020) 65e69
2.4. Statistical analysis Continuous variables are presented as medians and interquartile range (IQR), and categorical variables are presented as numbers and percentages (%). Univariate and multivariate logistic regression analyses were used to assess the association between LBP and lower extremity pain, and the odds ratio (OR) and 95% confidence interval (95% CI) for LBP were calculated. Variables considered in the analysis were sex (male or female), age (continuous variable), BMI (continuous variable), team level (low or high), number of days for training per week ( 3 or > 3 days), number of hours for practice on weekdays ( 2 or > 2 h), number of hours for practice per day on weekends ( 3 or > 3 h), and practice intensity (not hard or hard). In addition, we stratified lower extremity pain into knee and ankle pain, and the OR and 95% CI for LBP according to each pain were calculated in the same manner. Furthermore, associations between LBP and other covariates were evaluated and OR and 95% CI were calculated. All statistical analyses were performed using SPSS 24.0 (SPSS Japan Inc., Tokyo, Japan). A p-value of <0.05 was considered statistically significant.
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extremity pain among young volleyball players. Only a few reports have shown the prevalence of LBP among volleyball players (Noormohammadpour et al., 2016; Farahbakhsh et al., 2018). It has been reported that the point prevalence of LBP was 20.2% among 114 female university volleyball players and 23.5% among 81 male elite volleyball players (mean age 15 years) (Noormohammadpour et al., 2016; Farahbakhsh et al., 2018). Repetitive overhead motions are thought to put excessive load on the lower back (Fett, Trompeter, & Platen, 2019). A high frequency of jumping and landing also puts repetitive stress on the lower back (Fett et al., 2017). Volleyball contains a high volume of overhead motions with jumping, such as spiking, serving, and blocking with high velocity (Bere et al., 2015). Further, volleyball requires twisting, lateral bending, and asymmetrical movement of the lumbar spine (Smith et al., 2008). These motions can lead to LBP among volleyball
Table 2 Association of lower extremity pain with lower back pain among young volleyball players. Lower extremity pain
3. Results Baseline characteristics of participants are listed in Table 1. The median age was 11 (IQR: 10e12) years. The point prevalences of lower back, knee, and ankle pain among school-aged volleyball players were 9.5% (54/566), 12.0% (68/566), and 9.7% (55/566), respectively. Further, the prevalence of defined lower extremity pain was 18.2% (103/566). LBP was significantly associated with lower extremity pain in the crude and adjusted analyses. Using the absence of lower extremity pain as a reference, the adjusted OR (95% CI) for LBP was 11.07 (5.64e21.71) in the presence of lower extremity pain (Table 2). LBP was significantly associated with both knee and ankle pain in the crude and adjusted analyses. Using the absence of knee and ankle pain as a reference, the adjusted ORs (95% CI) for LBP were 8.72 (4.42e17.23) and 7.08 (3.41e4.69) in the presence of pain, respectively (Table 3). For the other covariates, LBP was significantly associated with age and the adjusted ORs (95% CI) for LBP was 1.99 (1.51e2.62). There were no association between LBP and other variables such as sex, BMI, team levels, number of days for training per week, number of hours for practice on weekdays or weekends, and practice intensity (Table 4). 4. Discussion The present study revealed that LBP is associated with lower
Lower back pain, n (%) Crude ORs (95% CI) Adjusted ORs (95% CI)
Absence (n ¼ 463)
Presence (n ¼ 103)
p value
18 (3.9) 1 1
36 (35.0) 13.28 (7.14e24.73) 11.07 (5.64e21.71)
<0.001 <0.001
Adjusted for sex, age, body mass index, team levels, number of days for training per week, number of hours in practice per day on weekdays and weekends, frequency of participation in games, and practice intensity. OR odds ratio, CI confidence interval.
Table 3 Association of knee or ankle pain with lower back pain among young volleyball players. Knee pain
Lower back pain, n (%) Crude ORs (95% CI) Adjusted ORs (95% CI)
Absence (n ¼ 498)
Presence (n ¼ 68)
p value
28 (5.6) 1 1
26 (38.2) 10.39 (5.59e19.32) 8.72 (4.42e17.23)
<0.001 <0.001
Absence (n ¼ 511)
Presence (n ¼ 55)
p value
33 (6.5) 1 1
21 (38.2) 8.95 (4.68e17.11) 7.08 (3.41e14.69)
<0.001 <0.001
Ankle pain
Lower back pain, n (%) Crude ORs (95% CI) Adjusted ORs (95% CI)
Adjusted for sex, age, body mass index, team levels, number of days for training per week, number of hours in practice per day on weekdays and weekends, frequency of participation in games, and practice intensity. OR odds ratio, CI confidence interval.
Table 1 Baseline characteristics of the participants. Variables
Categories
Sex
Male Female
Age (years) Body mass index Team levels Training per week (days) Practice per day weekdays (hours) Practice per day weekends (hours) Frequency of participation in games Practice intensity
Median (IQR)
N (%) 145 (25.6) 421 (74.4)
11.0 (10.0, 12.0) 17.5 (16.0, 19.2) Low High 3 >3 2 >2 3 >3 Sometimes or seldom Frequently Not hard Hard
330 236 273 293 321 245 256 310 252 314 342 224
(58.3) (31.4) (48.2) (51.8) (56.7) (43.3) (45.2) (54.8) (44.5) (55.5) (60.4) (39.6)
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Y. Yabe et al. / Physical Therapy in Sport 43 (2020) 65e69
Table 4 Association between lower back pain and other variables. Variables
Categories
n
Lower back pain
Sex
Male Female Per 1.0 increase Per 0.1 increase Low High 3 >3 2 >2 3 >3 Sometimes or seldom Frequently Not hard Hard
145 421
Presence, n (%) 11 (7.6) 43 (10.2)
330 236 273 293 321 245 256 310 252 314 342 224
27 27 17 37 31 23 20 34 17 37 28 26
Age (years) Body mass index Team levels Training per week (days) Practice per day weekdays (hours) Practice per day weekends (hours) Frequency of participation in games Practice intensity
(8.2) (11.4) (6.2) (12.6) (9.7) (9.4) (7.8) (11.0) (6.7) (11.8) (8.2) (11.6)
Adjusted ORs (95% CI) 1 2.41 (0.99e5.86) 1.99 (1.51e2.62) 0.96 (0.82e1.13) 1 1.23 (0.59e2.57) 1 2.07 (0.99e4.36) 1 1.03 (0.52e2.02) 1 1.04 (0.50e2.25) 1 0.83 (0.41e1.69) 1 1.16 (0.60e2.25)
p value 0.052 <0.001 0.611 0.589 0.055 0.937 0.66 0.606 0.66
OR odds ratio, CI confidence interval.
players. To the best of our knowledge, this is the first English report showing the point prevalence of LBP among elementary and middle school-aged volleyball players, which was 9.5%. This rate was lower than found in former reports of LBP among volleyball players (Noormohammadpour et al., 2016; Farahbakhsh et al., 2018). The younger age of the participants and differences in sex and competition levels are assumed to be a reason for the discrepancy. The point prevalence of LBP or back pain among elementary and middle school-aged athletes was reported to be 5.0%e8.0% (Muller et al., 2017; Yabe et al., 2017). LBP is considered more common in young volleyball players and it may be due to required body movement in volleyball. Effective prevention and treatment of LBP is important for young volleyball players. LBP was associated with lower extremity pain among young volleyball players. Some authors have reported an association between pain in different parts of the spine or the joints (Jonasson et al., 2011; Sekiguchi et al., 2018; Sogi et al., 2018; Yabe et al., 2019). It is considered that pain in one part of the body disrupts the kinematic chain during motion and can cause secondary injuries in other parts (Sekiguchi et al., 2017). Only a few reports have shown an association between lower extremity pain and LBP, and they were reported only in football and baseball (Sogi et al., 2018; Yabe et al., 2019). Lower extremities work to transfer energy from the ground to the lower back and disruption in the functions of these lower extremities due to pain can increase the impact on the lumbar spine (Nadler, Wu, Galski, & Feinberg, 1998). It was reported that lower extremity injuries in volleyball players adversely affect postural balance (Sarto et al., 2019), possibly increasing the stress on the lower back and the chance of lower back injuries during overhead motions. In the present study, 18.2% of young volleyball players reported lower extremity pain associated with LBP. Lower extremity pain was a common symptom and it was considered one reason for the high prevalence of LBP among young volleyball players. LBP was associated with both knee and ankle pain. The knees and ankles are the commonly reported sites of lower extremity injuries in volleyball players (Reeser, Gregory, Berg, & Comstock, 2015; Skazalski et al., 2018). Volleyball requires a high volume of jumping and landing, which puts repetitive stress on the knee and may cause knee pain (MacDonald, Palacios-Derflingher, Kenny, Emery, & Meeuwisse, 2018). Insufficient knee control upon landing has been reported to disrupt the knee’s ability to absorb the impact from the ground and transfers an excessive load of stress onto the lower back (Muller et al., 2015). Pain in the knee could impair its
function, and may increase the stress on the lower back and cause LBP. In volleyball, players sometimes land on the foot of an opponent or teammate in the conflict zone causing an ankle injury (Bahr & Bahr, 1997). During the landing phase of the jump, the ankle joint moves to dorsiflexion and works to absorb the impact force. Hypomobility of the ankle joint disrupts that function (MacDonald et al., 2018). Ankle pain could cause dysfunction of the ankle joint (Yeo & Wright, 2011) and lead to excessive loads of stress on the lower back (Brantingham, Lee Gilbert, Shaik, & Globe, 2006), possibly leading to LBP. The prevalences of knee and ankle pain in our study were 12.0% and 9.7%, respectively. Both knee and ankle pains were common symptoms reported by young volleyball players, and they were associated with LBP. Careful attention should be paid to knee and ankle complaints to maintain correct functions and to prevent and treat LBP. Considering other variables, LBP was significantly associated with age, as reported previously (Shah et al., 2014). It is thought that older athletes tend to play with higher levels in practice and that lumbar vertebrae during adolescence are vulnerable to injuries and may be related to LBP (Narita et al., 2014; Shah et al., 2014). Nevertheless, we found no association between LBP and sex, BMI, team levels, training days and hours, frequency of participation in games, or practice intensity. These have been reported as factors related to LBP (Fett et al., 2017; Noormohammadpour et al., 2016; Newlands et al., 2015). The participants of the present study were younger, and their competition levels and practice intensity were lower than those of the participants in these reports; this may account for the discrepancy. LBP was associated with lower extremity pain even in such young athletes who were deemed to be at low risk of LBP. This study had some limitations. First, a self-reported questionnaire and an informed consent form were mailed to the athletes, and the response rate was not high. The responders might have higher consciousness about sports activities, affecting the prevalence of pain or intensity of training and ultimately our results. Second, only sites of pain and not intensity or duration of pain were assessed. The reliability of this method was not confirmed in this study, possibly affecting the results. Finally, this study had a cross-sectional design, and reverse causality could not be ruled out. A longitudinal study should be done in the future. In conclusion, lower extremity pain, including knee and ankle pain, was associated with LBP among elementary and middle school-aged volleyball players. Careful attention should be paid to lower extremity complaints to prevent and treat LBP among young volleyball players.
Y. Yabe et al. / Physical Therapy in Sport 43 (2020) 65e69
Ethical approval The study protocol was reviewed and approved by the Ethics Committee on Research of Human Subjects at Tohoku University Graduate School of Medicine (Approved Number: 2013-564). Funding This study was funded by Asahi Soft Drink Co., Ltd. Declaration of competing interest None declared. Acknowledgements This study was performed as part of the Miyagi Sports Medical Projects and supported by Asahi Breweries. References Bahr, R., & Bahr, I. A. (1997). Incidence of acute volleyball injuries: A prospective cohort study of injury mechanisms and risk factors. Scandinavian Journal of Medicine & Science in Sports, 7, 166e171. Bere, T., Kruczynski, J., Veintimilla, N., Hamu, Y., & Bahr, R. (2015). Injury risk is low among world-class volleyball players: 4-year data from the FIVB injury surveillance system. British Journal of Sports Medicine, 49, 1132e1137. Brantingham, J. W., Lee Gilbert, J., Shaik, J., & Globe, G. (2006). Sagittal plane blockage of the foot, ankle and hallux and foot alignment-prevalence and association with low back pain. Journal of Chiropractic Medicine, 5, 123e127. Farahbakhsh, F., Akbari-Fakhrabadi, M., Shariat, A., Cleland, J. A., Farahbakhsh, F., Seif-Barghi, T., et al. (2018). Neck pain and low back pain in relation to functional disability in different sport activities. Journal of Exercise Rehabilitation, 14, 509e515. Farahbakhsh, F., Rostami, M., Noormohammadpour, P., Mehraki Zade, A., Hassanmirazaei, B., Faghih Jouibari, M., et al. (2018). Prevalence of low back pain among athletes: A systematic review. Journal of Back and Musculoskeletal Rehabilitation, 31, 901e916. Fett, D., Trompeter, K., & Platen, P. (2017). Back pain in elite sports: A cross-sectional study on 1114 athletes. PloS One, 12, e0180130. Fett, D., Trompeter, K., & Platen, P. (2019). Prevalence of back pain in a group of elite athletes exposed to repetitive overhead activity. PloS One, 14, e0210429. Hangai, M., Kaneoka, K., Okubo, Y., Miyakawa, S., Hinotsu, S., Mukai, N., et al. (2010). Relationship between low back pain and competitive sports activities during youth. The American Journal of Sports Medicine, 38, 791e796. Jonasson, P., Halldin, K., Karlsson, J., Thoreson, O., Hvannberg, J., Sward, L., et al. (2011). Prevalence of joint-related pain in the extremities and spine in five groups of top athletes. Knee Surgery, Sports Traumatology, Arthroscopy, 19, 1540e1546. Kilic, O., Maas, M., Verhagen, E., Zwerver, J., & Gouttebarge, V. (2017). Incidence, aetiology and prevention of musculoskeletal injuries in volleyball: A systematic review of the literature. European Journal of Sport Science, 17, 765e793. MacDonald, K., Palacios-Derflingher, L., Kenny, S., Emery, C., & Meeuwisse, W. H. (2018). Jumper’s knee: A prospective evaluation of risk factors in volleyball players using a novel measure of injury. Clinical Journal of Sport Medicine.
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Physical Therapy in Sport journal homepage: www.elsevier.com/ptsp
Original Research
Association between lower back pain and lower extremity pain among young volleyball players: A cross-sectional study Yutaka Yabe a, Yoshihiro Hagiwara a, b, *, Takuya Sekiguchi a, Haruki Momma b, Masahiro Tsuchiya c, Kenji Kanazawa a, Nobuyuki Itaya a, Shinichirou Yoshida a, Yasuhito Sogi a, Toshihisa Yano a, Takahiro Onoki a, Eiji Itoi a, Ryoichi Nagatomi b, d a
Department of Orthopaedic Surgery, Tohoku University School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan Department of Medicine and Science in Sports and Exercise, Tohoku University School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan Department of Nursing, Faculty of Health Science, Tohoku Fukushi University, 1-8-1 Kunimi, Aoba-ku, Sendai, 981-8522, Japan d Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 27 June 2019 Received in revised form 15 February 2020 Accepted 16 February 2020
Background: Lower back pain (LBP), as well as lower extremity injuries, are major problems among young volleyball players. Nevertheless, only few studies have focused on the relationship between lower extremity injuries and LBP. Objective: This study investigated the association between LBP and lower extremity pain, including knee and ankle pain, among young volleyball players. Design: Cross-sectional study. Setting: Amateur sports association. Participants: Elementary and middle school-aged athletes (6e15 years of age). Main outcome measures: LBP and lower extremity pain. Results: A total of 566 young volleyball players participated in this study. The point prevalence of LBP among young volleyball players was 9.5%. Using absence of lower extremity pain as a reference, the adjusted odds ratio (95% confidence interval) for LBP was 11.07 (5.64e21.71) in the presence of lower extremity pain. Conclusions: LBP is associated with Lower extremity pain among young volleyball players. Careful attention should be paid to lower extremity complaints to prevent and treat LBP among young volleyball players. © 2020 Elsevier Ltd. All rights reserved.
Keywords: Lower back pain School-aged athletes Lower extremity pain Volleyball
1. Introduction Volleyball is one of the most popular sports in the world, with 200 million players worldwide (Kilic, Maas, Verhagen, Zwerver, & Gouttebarge, 2017). Volleyball is considered to have a lower incidence of injuries than sports such as basketball, handball, or football that entail frequent tackles or contact with opponents (Bere, Kruczynski, Veintimilla, Hamu, & Bahr, 2015). Nevertheless, volleyball requires frequent jumping and sport-specific movements such as spiking, serving, and blocking, all of which put players at
* Corresponding author. Department of Orthopaedic Surgery, Tohoku University School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan. E-mail address: [email protected] (Y. Hagiwara). https://doi.org/10.1016/j.ptsp.2020.02.005 1466-853X/© 2020 Elsevier Ltd. All rights reserved.
risk for musculoskeletal injuries (Sarto, Grigoletto, Baggio, Paoli, & Marcolin, 2019). Whereas lower extremity injuries, including the knee and ankle, commonly occur among volleyball players (Bere et al., 2015), the lower back is the third most-frequent body part reported to incur injuries (Smith, Nyland, Caudill, Brosky, & Caborn, 2008). However, lower back injuries have not been studied extensively (Farahbakhsh, Rostami, et al., 2018). Currently, lower back pain (LBP) is reported as a common problem among young athletes as well as adults (Hangai et al., 2010). LBP leads to poor performance in young athletes and time loss participating in sports (Takemitsu, El Rassi, Woratanarat, & Shah, 2006). For these reasons, it is important to understand the factors related to LBP to prevent and treat LBP among young athletes. Factors, such as sex (Fett, Trompeter, & Platen, 2017), age (Shah, Cloke, Rushton, Shirley, & Deehan, 2014), body mass index
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(BMI) (Noormohammadpour et al., 2016), competition level (Fett et al., 2017), and intensity of training (Newlands, Reid, & Parmar, 2015) have previously been reported to be associated with LBP among athletes. Furthermore, the prevalence of LBP varies between different types of sports because each sport requires certain body movements and the load imposed on the lumbar spine is different among the various sports (Farahbakhsh, Akbari-Fakhrabadi, et al., 2018). Considering LBP among young volleyball players, dysfunction of the lower extremities due to pain can lead to LBP because motions in volleyball such as spiking, blocking, and serving, need coordinated movements of the lower extremities and lumbar spine. To prevent and treat LBP among young volleyball players, it is important to determine whether there is an association of lower extremity complaints with LBP. However, to the best of our knowledge, no reports have evaluated this association among volleyball players. Therefore, the purpose of this study was to determine the association between LBP and lower extremity pain, including knee and ankle pain, among young volleyball players. 2. Materials and methods 2.1. Participants A cross-sectional study was performed with elementary and middle school-aged athletes (6e15 years of age) belonging to an amateur sports association using a self-reported questionnaire for a comprehensive survey of their sports activities, lifestyles, and problems in sports. Many types of sports, including baseball, football, basketball, volleyball, and judo, were included in the association. The association possessed mailing address of registered athletes; a self-reported questionnaire and an informed consent form were mailed to all of them in October 2014 (n ¼ 25,469). All participants were asked to answer the questionnaire by themselves; however, parents were allowed to help younger participants. Among the registered athletes, 7333 consented to this study and responded to the questionnaire (response rate of 28.8%). Respondents who did not play volleyball (n ¼ 6646) or who played other sports together with volleyball (n ¼ 6) were excluded. The
respondents with missing data were excluded from the analysis (n ¼ 115) to yield a final sample size of 566 volleyball players (Fig. 1).
2.2. Lower back and lower extremity pain LBP and lower extremity pain were assessed by the following question, “Do you have pain in any parts of your body? If yes, please check the parts you have pain”. Body parts, including the head, lower back, and each joint, were illustrated by a drawing and multiple-choice answers were allowed. Participants who checked lower back, knee, or ankle were determined to have LBP, knee pain, or ankle pain, respectively. Further, the participants who had knee pain and/or ankle pain were defined to have lower extremity pain.
2.3. Covariates The covariates used in the analysis were sex, age, BMI (calculated using self-reported height and weight values), team level (recreation, local competition, prefectural competition, distinct competition, or national competition), number of days for training per week, number of hours for practice per day on weekdays and weekends, frequency of participation in games (never, seldom, sometimes, or often), and practice intensity (not hard or hard) because they were considered potential cofounding factors. The following continuous variables were divided into categories by the distribution according to previous reports (Yabe et al., 2017; Sekiguchi et al., 2018): number of days for training per week was categorized into two groups ( 3 and > 3 days per week); number of hours for practice per day on weekdays was placed into two groups ( 2 and > 2 h per day); and number of hours for practice per day on weekends was divided into two groups ( 3 and > 3 h per day). The following categorical variables were divided into groups according to the distribution: team level (low: “recreation” or “local competition”; high: “prefectural competition” or higher) and frequency of participation in games (sometimes or seldom: “never”, “seldom”, or “sometimes”; frequently: “often”).
Fig. 1. Flow chart of the study.
Y. Yabe et al. / Physical Therapy in Sport 43 (2020) 65e69
2.4. Statistical analysis Continuous variables are presented as medians and interquartile range (IQR), and categorical variables are presented as numbers and percentages (%). Univariate and multivariate logistic regression analyses were used to assess the association between LBP and lower extremity pain, and the odds ratio (OR) and 95% confidence interval (95% CI) for LBP were calculated. Variables considered in the analysis were sex (male or female), age (continuous variable), BMI (continuous variable), team level (low or high), number of days for training per week ( 3 or > 3 days), number of hours for practice on weekdays ( 2 or > 2 h), number of hours for practice per day on weekends ( 3 or > 3 h), and practice intensity (not hard or hard). In addition, we stratified lower extremity pain into knee and ankle pain, and the OR and 95% CI for LBP according to each pain were calculated in the same manner. Furthermore, associations between LBP and other covariates were evaluated and OR and 95% CI were calculated. All statistical analyses were performed using SPSS 24.0 (SPSS Japan Inc., Tokyo, Japan). A p-value of <0.05 was considered statistically significant.
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extremity pain among young volleyball players. Only a few reports have shown the prevalence of LBP among volleyball players (Noormohammadpour et al., 2016; Farahbakhsh et al., 2018). It has been reported that the point prevalence of LBP was 20.2% among 114 female university volleyball players and 23.5% among 81 male elite volleyball players (mean age 15 years) (Noormohammadpour et al., 2016; Farahbakhsh et al., 2018). Repetitive overhead motions are thought to put excessive load on the lower back (Fett, Trompeter, & Platen, 2019). A high frequency of jumping and landing also puts repetitive stress on the lower back (Fett et al., 2017). Volleyball contains a high volume of overhead motions with jumping, such as spiking, serving, and blocking with high velocity (Bere et al., 2015). Further, volleyball requires twisting, lateral bending, and asymmetrical movement of the lumbar spine (Smith et al., 2008). These motions can lead to LBP among volleyball
Table 2 Association of lower extremity pain with lower back pain among young volleyball players. Lower extremity pain
3. Results Baseline characteristics of participants are listed in Table 1. The median age was 11 (IQR: 10e12) years. The point prevalences of lower back, knee, and ankle pain among school-aged volleyball players were 9.5% (54/566), 12.0% (68/566), and 9.7% (55/566), respectively. Further, the prevalence of defined lower extremity pain was 18.2% (103/566). LBP was significantly associated with lower extremity pain in the crude and adjusted analyses. Using the absence of lower extremity pain as a reference, the adjusted OR (95% CI) for LBP was 11.07 (5.64e21.71) in the presence of lower extremity pain (Table 2). LBP was significantly associated with both knee and ankle pain in the crude and adjusted analyses. Using the absence of knee and ankle pain as a reference, the adjusted ORs (95% CI) for LBP were 8.72 (4.42e17.23) and 7.08 (3.41e4.69) in the presence of pain, respectively (Table 3). For the other covariates, LBP was significantly associated with age and the adjusted ORs (95% CI) for LBP was 1.99 (1.51e2.62). There were no association between LBP and other variables such as sex, BMI, team levels, number of days for training per week, number of hours for practice on weekdays or weekends, and practice intensity (Table 4). 4. Discussion The present study revealed that LBP is associated with lower
Lower back pain, n (%) Crude ORs (95% CI) Adjusted ORs (95% CI)
Absence (n ¼ 463)
Presence (n ¼ 103)
p value
18 (3.9) 1 1
36 (35.0) 13.28 (7.14e24.73) 11.07 (5.64e21.71)
<0.001 <0.001
Adjusted for sex, age, body mass index, team levels, number of days for training per week, number of hours in practice per day on weekdays and weekends, frequency of participation in games, and practice intensity. OR odds ratio, CI confidence interval.
Table 3 Association of knee or ankle pain with lower back pain among young volleyball players. Knee pain
Lower back pain, n (%) Crude ORs (95% CI) Adjusted ORs (95% CI)
Absence (n ¼ 498)
Presence (n ¼ 68)
p value
28 (5.6) 1 1
26 (38.2) 10.39 (5.59e19.32) 8.72 (4.42e17.23)
<0.001 <0.001
Absence (n ¼ 511)
Presence (n ¼ 55)
p value
33 (6.5) 1 1
21 (38.2) 8.95 (4.68e17.11) 7.08 (3.41e14.69)
<0.001 <0.001
Ankle pain
Lower back pain, n (%) Crude ORs (95% CI) Adjusted ORs (95% CI)
Adjusted for sex, age, body mass index, team levels, number of days for training per week, number of hours in practice per day on weekdays and weekends, frequency of participation in games, and practice intensity. OR odds ratio, CI confidence interval.
Table 1 Baseline characteristics of the participants. Variables
Categories
Sex
Male Female
Age (years) Body mass index Team levels Training per week (days) Practice per day weekdays (hours) Practice per day weekends (hours) Frequency of participation in games Practice intensity
Median (IQR)
N (%) 145 (25.6) 421 (74.4)
11.0 (10.0, 12.0) 17.5 (16.0, 19.2) Low High 3 >3 2 >2 3 >3 Sometimes or seldom Frequently Not hard Hard
330 236 273 293 321 245 256 310 252 314 342 224
(58.3) (31.4) (48.2) (51.8) (56.7) (43.3) (45.2) (54.8) (44.5) (55.5) (60.4) (39.6)
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Table 4 Association between lower back pain and other variables. Variables
Categories
n
Lower back pain
Sex
Male Female Per 1.0 increase Per 0.1 increase Low High 3 >3 2 >2 3 >3 Sometimes or seldom Frequently Not hard Hard
145 421
Presence, n (%) 11 (7.6) 43 (10.2)
330 236 273 293 321 245 256 310 252 314 342 224
27 27 17 37 31 23 20 34 17 37 28 26
Age (years) Body mass index Team levels Training per week (days) Practice per day weekdays (hours) Practice per day weekends (hours) Frequency of participation in games Practice intensity
(8.2) (11.4) (6.2) (12.6) (9.7) (9.4) (7.8) (11.0) (6.7) (11.8) (8.2) (11.6)
Adjusted ORs (95% CI) 1 2.41 (0.99e5.86) 1.99 (1.51e2.62) 0.96 (0.82e1.13) 1 1.23 (0.59e2.57) 1 2.07 (0.99e4.36) 1 1.03 (0.52e2.02) 1 1.04 (0.50e2.25) 1 0.83 (0.41e1.69) 1 1.16 (0.60e2.25)
p value 0.052 <0.001 0.611 0.589 0.055 0.937 0.66 0.606 0.66
OR odds ratio, CI confidence interval.
players. To the best of our knowledge, this is the first English report showing the point prevalence of LBP among elementary and middle school-aged volleyball players, which was 9.5%. This rate was lower than found in former reports of LBP among volleyball players (Noormohammadpour et al., 2016; Farahbakhsh et al., 2018). The younger age of the participants and differences in sex and competition levels are assumed to be a reason for the discrepancy. The point prevalence of LBP or back pain among elementary and middle school-aged athletes was reported to be 5.0%e8.0% (Muller et al., 2017; Yabe et al., 2017). LBP is considered more common in young volleyball players and it may be due to required body movement in volleyball. Effective prevention and treatment of LBP is important for young volleyball players. LBP was associated with lower extremity pain among young volleyball players. Some authors have reported an association between pain in different parts of the spine or the joints (Jonasson et al., 2011; Sekiguchi et al., 2018; Sogi et al., 2018; Yabe et al., 2019). It is considered that pain in one part of the body disrupts the kinematic chain during motion and can cause secondary injuries in other parts (Sekiguchi et al., 2017). Only a few reports have shown an association between lower extremity pain and LBP, and they were reported only in football and baseball (Sogi et al., 2018; Yabe et al., 2019). Lower extremities work to transfer energy from the ground to the lower back and disruption in the functions of these lower extremities due to pain can increase the impact on the lumbar spine (Nadler, Wu, Galski, & Feinberg, 1998). It was reported that lower extremity injuries in volleyball players adversely affect postural balance (Sarto et al., 2019), possibly increasing the stress on the lower back and the chance of lower back injuries during overhead motions. In the present study, 18.2% of young volleyball players reported lower extremity pain associated with LBP. Lower extremity pain was a common symptom and it was considered one reason for the high prevalence of LBP among young volleyball players. LBP was associated with both knee and ankle pain. The knees and ankles are the commonly reported sites of lower extremity injuries in volleyball players (Reeser, Gregory, Berg, & Comstock, 2015; Skazalski et al., 2018). Volleyball requires a high volume of jumping and landing, which puts repetitive stress on the knee and may cause knee pain (MacDonald, Palacios-Derflingher, Kenny, Emery, & Meeuwisse, 2018). Insufficient knee control upon landing has been reported to disrupt the knee’s ability to absorb the impact from the ground and transfers an excessive load of stress onto the lower back (Muller et al., 2015). Pain in the knee could impair its
function, and may increase the stress on the lower back and cause LBP. In volleyball, players sometimes land on the foot of an opponent or teammate in the conflict zone causing an ankle injury (Bahr & Bahr, 1997). During the landing phase of the jump, the ankle joint moves to dorsiflexion and works to absorb the impact force. Hypomobility of the ankle joint disrupts that function (MacDonald et al., 2018). Ankle pain could cause dysfunction of the ankle joint (Yeo & Wright, 2011) and lead to excessive loads of stress on the lower back (Brantingham, Lee Gilbert, Shaik, & Globe, 2006), possibly leading to LBP. The prevalences of knee and ankle pain in our study were 12.0% and 9.7%, respectively. Both knee and ankle pains were common symptoms reported by young volleyball players, and they were associated with LBP. Careful attention should be paid to knee and ankle complaints to maintain correct functions and to prevent and treat LBP. Considering other variables, LBP was significantly associated with age, as reported previously (Shah et al., 2014). It is thought that older athletes tend to play with higher levels in practice and that lumbar vertebrae during adolescence are vulnerable to injuries and may be related to LBP (Narita et al., 2014; Shah et al., 2014). Nevertheless, we found no association between LBP and sex, BMI, team levels, training days and hours, frequency of participation in games, or practice intensity. These have been reported as factors related to LBP (Fett et al., 2017; Noormohammadpour et al., 2016; Newlands et al., 2015). The participants of the present study were younger, and their competition levels and practice intensity were lower than those of the participants in these reports; this may account for the discrepancy. LBP was associated with lower extremity pain even in such young athletes who were deemed to be at low risk of LBP. This study had some limitations. First, a self-reported questionnaire and an informed consent form were mailed to the athletes, and the response rate was not high. The responders might have higher consciousness about sports activities, affecting the prevalence of pain or intensity of training and ultimately our results. Second, only sites of pain and not intensity or duration of pain were assessed. The reliability of this method was not confirmed in this study, possibly affecting the results. Finally, this study had a cross-sectional design, and reverse causality could not be ruled out. A longitudinal study should be done in the future. In conclusion, lower extremity pain, including knee and ankle pain, was associated with LBP among elementary and middle school-aged volleyball players. Careful attention should be paid to lower extremity complaints to prevent and treat LBP among young volleyball players.
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