Low back pain in college athletes. A prospective study correlating lower extremity overuse or acquired ligamentous laxity with low back pain

Prevalence and associated factors of non-traumatic knee pain in high school volleyball players: a cross-sectional study

OBJECTIVES

This study aimed to determine the prevalence of knee pain among high school volleyball attackers, identify associated factors, and explore the relationship between knee pain and lower back pain (LBP).

METHODS

A cross-sectional study involving 82 high school volleyball attackers (15-17 years) used questionnaires, interviews, and field-based assessments to collect data on demographics, volleyball-specific factors, flexibility, and jumping ability. Logistic regression analysis was used to identify factors associated with knee pain.

RESULTS

The prevalence of knee pain was 19.5%. Factors significantly associated with knee pain were a history of LBP (OR, 4.64; 95% CI, 1.28 to 16.8; p = 0.019) and flexibility determined by the absolute difference in heel-buttock distance (OR, 1.37; 95% CI, 1.02 to 1.83; p = 0.037). Participants with knee pain had more volleyball experience and a higher proportion of players who competed as starters in the previous year. Both groups reported approximately 18 hours of practice per week during the school year and around 27 hours during school holidays, with no significant difference observed.

CONCLUSION

Factors associated with knee pain include a history of LBP and reduced flexibility on the heel-buttock distance test. The study highlights the need for a comprehensive approach, considering the coexistence of LBP and focusing on improving anterior thigh flexibility.

Prevalence, diagnosis and management of musculoskeletal disorders in elite athletes: A mini-review

Musculoskeletal injuries in elite sports are ones of the most impact issue because their remarkable impact on performance caused by drastic absence of training and competition and a progressive deterioration in physical health, emotional and social athletes' dimensions. Also, the prevalence of epidemiologic research found an incidence of musculoskeletal disorders vary within sports and in elite athletes which is even higher as a consequence of higher demand physical performance. This way, the loss of physical performance due to an sport injury impacts not only the individual economic sphere of the professional but also that ofsports entities, reaching, according to some studies, a loss estimated in the range of 74.7 million pounds. Thus, the purpose of this article is to review and to provide an overview of the most common musculoskeletal injuries in elite sports precipitating factors, clinical presentation, evidence-based diagnostic evaluation, and treatment recommendations with a view to preventing medical conditions or musculoskeletal injuries that may alter performance and general health in the elite athletes.

Point Prevalence of the Biomechanical Dimension of Dysfunctional Breathing Patterns Among Competitive Athletes

ABSTRACT

Shimozawa, Y, Kurihara, T, Kusagawa, Y, Hori, M, Numasawa, S, Sugiyama, T, Tanaka, T, Suga, T, Terada, RS, Isaka, T, and Terada, M. Point prevalence of the biomechanical dimension of dysfunctional breathing patterns among competitive athletes. J Strength Cond Res 37(2): 270-276, 2023-There is growing evidence of associations between altered biomechanical breathing patterns and numerous musculoskeletal and psychological conditions. The prevalence of dysfunctional and diaphragmatic breathing patterns is unknown among athletic populations. The purpose of this study was to examine the prevalence of dysfunctional and diaphragmatic breathing patterns among athletic populations with a clinical measure to assess the biomechanical dimension of breathing patterns. Using a cross-sectional design, 1,933 athletes across multiple sports and ages were screened from 2017 to 2020. Breathing patterns were assessed using the Hi-Lo test in the standing position. Scores of the Hi-Lo test were determined based on the presence or absence of abdominal excursion, anterior-posterior chest expansion, superior rib cage migration, and shoulder elevation. The Hi-Lo test scores were used to categorize observational breathing mechanics as dysfunctional and diaphragmatic breathing patterns. The prevalence of athletes with dysfunctional breathing patterns was 90.6% (1,751 of 1,933). Athletes with diaphragmatic breathing patterns accounted for 9.4% of all athletes in our sample (182 of 1,933). There were no differences in the proportion of breathing patterns between male and female athletes ( p = 0.424). Breathing patterns observations were associated with sport-setting categories ( p = 0.002). The highest percentages of dysfunctional breathers were in middle school student athletes (93.7%), followed by elementary school student athletes (91.2%), high school student athletes (90.6%), professional/semiprofessional athletes (87.5%), and collegiate athletes (84.8%). The current study observed that dysfunctional breathing patterns (90.6%) in the biomechanical dimension were more prevalent than diaphragmatic breathing pattern (9.4%) among competitive athletes. These results suggest that clinicians may need to consider screening breathing patterns and implementing intervention programs aimed to improve the efficiency of biomechanical dimensions of breathing patterns in athletic populations. This study may help raise awareness of impacts of dysfunctional breathing patterns on athletes' health and performance.

Prevalence, patterns and factors associated with injury: comparison between elite Malaysian able-bodied and para-badminton players

OBJECTIVES

This study aimed to determine and compare the prevalence, patterns and factors associated with injury between elite Malaysian able-bodied and para-badminton players.

METHODS

Medical records from July 2007 to December 2017 were reviewed.

RESULTS

Among 209 able-bodied players, 1010 injuries were reported. The injuries affected the lower limb (67.2%), sustained during training (94.2%), overuse in nature (38.7%), and involving mostly junior players (62.4%). The injury rate was 94/year, lower than previously reported. Patellar tendinopathy and muscle strain to the upper limb and torso were the commonest. Age, sex and history of injury were predictors of injury. Lower limb injury was a predictor of upper limb and torso injuries, while history of injury to the upper limb and/or torso was a predictor of lower limb injury. Meanwhile, among 18 para-badminton players, 62 injuries were reported from July 2014 to December 2017, which involved the lower limb (45.2%), sustained during training (87.1%), overuse in nature (54.8%), and involved mostly standing-class players (77.8%). The injury rate was 10/year. Patellar tendinopathy, rotator cuff tendinopathy and back muscle strain were the commonest. The patterns of injury (site, occasion and nature) were similar between groups, except for the shoulder where nature was overuse in para-badminton players compared to acute in able-bodied players.

CONCLUSIONS

All players are susceptible to training-related injuries, particularly to the lower limb. Over the last decade, an increase in the injury index for the lower limb and a shift from chronic to acute for the upper limb were observed among able-bodied players. Age, sex and history of injury expose able-bodied players to greater risk. Meanwhile, for para-badminton players, overuse shoulder and knee injuries are commonest. These findings necessitate a comprehensive injury prevention program that encompasses all body regions with an emphasis on the lower limb among elite Malaysian able-bodied and para-badminton players.

Lumbopelvic Stability and Trunk Muscle Contractility of Individuals with Chronic Ankle Instability

Background

Chronic ankle instability (CAI) results in hip neuromuscular impairments that can perpetuate dysfunction through reduced lumbopelvic stability and subsequent malpositioning of the lower body during functional movement. Lumbopelvic stability might be further impaired through changes in trunk muscular contractility. However, lumbopelvic stability and trunk muscle morphology have not been compared between individuals with and without CAI.

Purpose

To compare lumbopelvic stability and trunk muscle contractility between individuals with and without chronic ankle instability (CAI) and determine if lumbopelvic stability and trunk muscle contractility are associated with self-reported function.

Study Design

Case-control study.

Methods

Ten individuals with CAI, 10 ankle sprain copers (COP), and 10 healthy controls (CON) participated. Diagnostic ultrasound imaging was used to assess transversus abdominis (TrA) and lumbar multifidus (LM) muscle contractility. A percent change in contraction thickness from rested to contracted conditions was calculated for each muscle. Lumbopelvic stability was assessed using unilateral hip bridge, trunk flexion endurance, Biering-Sorensen, and side plank tests. Self-reported function was measured with the Foot and Ankle Ability Measure Activity of Daily Living (FAAM-ADL) and Sport (FAAM-S) subscales. One-way ANOVAs and Cohen’s d effect sizes compared scores on clinician and patient-reported outcomes between groups. Pearson product moment correlations analyzed associations between self-reported function and trunk muscle contractility and lumbopelvic stability. Significance was set a priori at P<0.05

Results

COP had significantly greater TrA contractility than CAI (P<0.01, d=2.65[1.45,3.85]) and CON (P=0.03, d=1.05[0.08,1.94]). Although not statistically significant, a large effect size suggest that CAI had lower TrA contractility than CON (P=0.12, d=0.92[-0.03,1.80]). No differences existed for LM contractility or lumbopelvic stability tests. A moderate direct correlation (r=0.65, P=0.04) existed between CON’s TrA contractility and FAAM-ADL scores.

Conclusion

Deficits in TrA contractility are a novel finding among individuals with CAI. While LM contractility and lumbopelvic stability did not differ between groups, future research should continue to examine their relevance to CAI.

Level of Evidence

3b

Water Ski Injuries and Chronic Pain in Collegiate Athletes

This study examined the rate of injuries and chronic pain in collegiate water-ski athletes as a preliminary study. We also compared the mechanics and cause of injuries by the level of water-skiing experiences. A total number of 96 collegiate water-ski athletes, aged 21.4 ± 2.23 years, participated in the study. An off-line questionnaire was distributed at the collegiate tournaments in the United States. The questionnaire consisted of 20 questions, including demographic information, body region and type of injuries, mechanics and cause of injuries, chronic pain and pain management. A Chi-squared test was used to examine the differences in injury rates by sex and the level of experiences (beginner: <5 years, intermediate: 5–10 years, advanced: <10 years). The significance level was set at ≤0.05. A total of 336 water skiing-related injuries were observed from 96 participants. The ankle/feet, knee, and head/neck regions were the most common body regions injured, representing 26.5, 16.7, and 15.8%, respectively. Female athletes were more likely to have nerve injuries than male athletes (p = 0.039). The intermediate athletes were more likely to have trunk (p = 0.047) and upper extremity (p = 0.042) injuries than beginner athletes, and the beginner athletes had less joint/ligament (p = 0.001) and bone injury (p = 0.010) compared to the advanced athletes. Torsion/twisting (32.8%) and deceleration (26.9%) were the most common mechanism of injury. Beginner athletes experienced injuries more due to insufficient skill (p = 0.03), while the advanced athletes were likely to have more injuries by the loss of control (p = 0.01). Collegiate athletes had higher rates of chronic pain in the trunk (42.7%) and skeletal muscle (43.8%), and they participated in stretching/exercise (40.8%) and massage/form rolling (29.6%) to manage their chronic pain. The present study revealed that injury rates in males and females were 49.7% and 50.2%, respectively. Female athletes were more likely to have a nerve injury than male athletes. The mechanics and cause of injuries were different by the level of experiences where different training approaches may be required to minimize the injuries. Additionally, the strength and conditioning program that is systematically designed for core strength is needed to eliminate chronic trunk pain in collegiate water-skiing athletes.

The effect of chronic ankle instability on muscle activations in lower extremities

BACKGROUND/PURPOSE

Muscular reflex responses of the lower extremities to sudden gait disturbances are related to postural stability and injury risk. Chronic ankle instability (CAI) has shown to affect activities related to the distal leg muscles while walking. Its effects on proximal muscle activities of the leg, both for the injured- (IN) and uninjured-side (NON), remain unclear. Therefore, the aim was to compare the difference of the motor control strategy in ipsilateral and contralateral proximal joints while unperturbed walking and perturbed walking between individuals with CAI and matched controls.

MATERIALS AND METHODS

In a cross-sectional study, 13 participants with unilateral CAI and 13 controls (CON) walked on a split-belt treadmill with and without random left- and right-sided perturbations. EMG amplitudes of muscles at lower extremities were analyzed 200 ms after perturbations, 200 ms before, and 100 ms after (Post100) heel contact while walking. Onset latencies were analyzed at heel contacts and after perturbations. Statistical significance was set at alpha≤0.05 and 95% confidence intervals were applied to determine group differences. Cohen's d effect sizes were calculated to evaluate the extent of differences.

RESULTS

Participants with CAI showed increased EMG amplitudes for NON-rectus abdominus at Post100 and shorter latencies for IN-gluteus maximus after heel contact compared to CON (p<0.05). Overall, leg muscles (rectus femoris, biceps femoris, and gluteus medius) activated earlier and less bilaterally (d = 0.30-0.88) and trunk muscles (bilateral rectus abdominus and NON-erector spinae) activated earlier and more for the CAI group than CON group (d = 0.33-1.09).

CONCLUSION

Unilateral CAI alters the pattern of the motor control strategy around proximal joints bilaterally. Neuromuscular training for the muscles, which alters motor control strategy because of CAI, could be taken into consideration when planning rehabilitation for CAI.

Prevalence and risk factors for back pain in sports: a systematic review with meta-analysis

OBJECTIVES

We aimed to determine the prevalence of low back pain (LBP) in sport, and what risk factors were associated with LBP in athletes.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

Literature searches from database inception to June 2019 in Medline, Embase, Cumulated Index to Nursing and Allied Health Literature (CINAHL), Web of Science and Scopus, supplemented by grey literature searching.

ELIGIBILITY CRITERIA

Studies evaluating prevalence of LBP in adult athletes across all sports.

RESULTS

Eighty-six studies were included (30 732, range 20-5958, participants), of which 45 were of 'high' quality. Definitions of LBP varied widely, and in 17 studies, no definition was provided. High-quality studies were pooled and the mean point prevalence across six studies was 42%; range 18%-80% (95% CI 27% to 58%, I2=97%). Lifetime prevalence across 13 studies was 63%; range 36%-88% (95% CI 51% to 74%, I2=99%). Twelve-month LBP prevalence from 22 studies was 51%; range 12%-94% (95% CI 41% to 61%, I2=98%). Comparison across sports was limited by participant numbers, study quality and methodologies, and varying LBP definitions. Risk factors for LBP included history of a previous episode with a pooled OR of 3.5; range 1.6-4.0 (95% CI 1.9 to 6.4). Statistically significant associations were reported for high training volume, periods of load increase and years of exposure to the sport.

CONCLUSION

LBP in sport is common but estimates vary. Current evidence is insufficient to identify which sports are at highest risk. A previous episode of LBP, high training volume, periods of load increase and years of exposure are common risk factors.

Sports Imaging of Team Handball Injuries

Team handball is a fast high-scoring indoor contact sport with > 20 million registered players who are organized in > 150 federations worldwide. The combination of complex and unique biomechanics of handball throwing, permitted body tackles and blocks, and illegal fouls contribute to team handball ranging among the four athletic sports that carry the highest risks of injury. The categories include a broad range of acute and overuse injuries that most commonly occur in the shoulder, knee, and ankle. In concert with sports medicine, physicians, surgeons, physical therapists, and radiologists consult in the care of handball players through the appropriate use and expert interpretations of radiography, ultrasonography, CT, and MRI studies to facilitate diagnosis, characterization, and healing of a broad spectrum of acute, complex, concomitant, chronic, and overuse injuries. This article is based on published data and the author team's cumulative experience in playing and caring for handball players in Denmark, Sweden, Norway, Germany, Switzerland, and Spain. The article reviews and illustrates the spectrum of common handball injuries and highlights the contributions of sports imaging for diagnosis and management.

Upper Extremity Pain Is Associated with Lower Back Pain among Young Basketball Players: A Cross-Sectional Study

Basketball is a major sport worldwide among different age groups that leads to a high frequency of injuries at multiple body sites. Upper and lower extremities and lower back are common pain sites in basketball players; however, there is little information about the relationship between upper or lower extremity pain and lower back pain. This study elucidated the associations between upper extremity (shoulder and elbow) pain and lower back pain (LBP) among young basketball players. We conducted a cross-sectional study using self-reported questionnaires mailed to 25,669 young athletes; the final study population comprised 590 basketball players, and their median age was 13 years (range: 6-15 years). The point prevalence rates of lower back, shoulder, elbow, and upper extremity pain among young basketball players were 12.9% (76/590), 4.6% (27/590), 2.7% (16/590), and 7.1% (42/590), respectively. Multivariate logistic regression analyses revealed that upper extremity pain was significantly associated with LBP (adjusted odds ratio [OR]: 7.86; 95% confidential interval [CI], 3.93-15.72). Shoulder pain was significantly associated with training per week (> 4 days) (adjusted OR: 4.15; 95% CI: 1.29-13.40) and LBP (adjusted OR: 13.77; 95% CI: 5.70-33.24). This study indicates that upper extremity and shoulder pain is associated with LBP among young basketball players. Assessing for lower back pain, as well as elbow and/or shoulder pain, may help prevent severe injuries in young basketball players. In conclusion, parents and coaches should be properly re-educated to help improve lower back, upper extremity, and shoulder pain among young basketball players.

Low Back Pain in School-Aged Martial Arts Athletes in Japan: A Comparison among Judo, Kendo, and Karate

Martial arts, such as judo, kendo, and karate, are popular worldwide, not only among adults but also among children and adolescents. Although low back pain (LBP) is considered to be a common problem in these sports, it has been scarcely studied, especially in young athletes. The purpose of this study was to elucidate the point prevalence of and factors related to LBP among school-aged athletes in judo, kendo, and karate. A cross-sectional study was conducted in school-aged athletes (age, 6-15 years; n = 896) using a self-reported questionnaire. Multiple logistic regression models were used to assess the factors related to LBP along with the odds ratio (OR) and 95% confidence interval (95% CI). Variables included in the analysis were sex, age, body mass index, team level, number of days and hours of training, frequency of participation in games, practice intensity, and lower extremity pain. The prevalence of LBP was 6.9% in judo, 4.7% in kendo, and 2.9% in karate. Older age was significantly associated with LBP in judo (adjusted OR, 2.12 [95% CI, 1.24-3.61]), kendo (1.77 [1.27-2.47]), and karate (2.22 [1.14-4.33]). Lower extremity pain was significantly associated with LBP in judo (6.56 [1.57-27.34]) and kendo (21.66 [6.96-67.41]). Coaches should understand the characteristics of LBP in each martial art to develop strategies to prevent LBP among school-aged martial arts athletes.

The relationship between depressive symptoms, somatic complaints, and concussion history with poor sleep in collegiate athletes

OBJECTIVE

Ongoing exploration of factors related to poor sleep in collegiate athletes is important as understanding of the risks and consequences of poor sleep in this specific population increases.

DESIGN

Retrospective cohort study.

SETTING

University in the Pacific Northwest.

PARTICIPANTS

One-hundred thirty-seven male and female collegiate athletes across 5 collision, contact, and limited contact team sports.

MEASUREMENTS

Depressive symptoms (Patient Health Questionnaire 9; PHQ-9), anxiety symptoms (General Anxiety Disorder 7; GAD-7), and somatic complaints (Patient Health Questionnaire 15; PHQ-15). Sleep quality (Pittsburgh Sleep Quality Index; PSQI) used both a cutoff score ≥6 and a cutoff score of ≥8, indicating "poor sleep quality" to reduce threats to divergent validity.

RESULTS

Poor sleep quality as defined by PSQI ≥ 6 was present in 53% of athletes, and as defined by PSQI ≥ 8 was identified in 33.5% of the cohort. There were no differences in the incidence of poor sleepers between sport, race/ethnicity, or sex. Multiple regression analysis revealed that depressive symptoms, somatic complaints, Caucasian race, male sex, and number of concussions were significant predictors of poor sleep (P < .05). The model accounted for 43% of the variance in PSQI and primarily by depressive symptoms explaining 9% of reported sleep quality variability. Anxiety symptoms, sport category, and history of migraines were not significant predictors of poor sleep quality.

CONCLUSIONS

A high incidence of poor sleep among collegiate athletes was observed regardless of sport, and may be related to depressive symptoms, somatic complaints, Caucasian race, male sex, and historical number of concussions.

High prevalence of low back pain among young basketball players with lower extremity pain: a cross-sectional study

Background

Low back pain (LBP) is a common problem among young basketball players in addition to lower extremity injuries. However, studies that focus on LBP with lower extremity pain are limited. From the perspective of the kinematic chain, disrupted lower extremity function can lead to LBP. The association between these two symptoms in basketball players, however, has not been reported. Therefore, this study aimed to clarify the association between lower extremity pain and LBP among young basketball players.

Methods

This cross-sectional study was conducted on school-aged basketball players (n = 592). Information regarding their sporting activities was collected using a self-reported questionnaire. Musculoskeletal pain such as low back, knee, and ankle pain was assessed. The sports players with knee and/or ankle pain were defined as having lower extremity pain. Multivariate logistic regression analysis was used to assess the association between lower extremity pain and LBP. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated. The associations of knee or ankle pain with LBP were similarly assessed.

Results

School-aged basketball players had a point prevalence of 12.8% for LBP. Compared with the players without lower extremity pain, the players with lower extremity pain had higher rates of LBP, with an adjusted OR (95% CI) of 6.21 (3.57-10.80). There was also a significant association of knee and ankle pain with LBP. Compared with the players without knee or ankle pain, the adjusted ORs (95% CI) for LBP were 4.25 (2.55-7.07) in the players with knee pain and 3.79 (2.26-6.36) in the players with ankle pain.

Conclusions

Lower extremity pain was associated with LBP among school-aged basketball players. Further research is needed to clarify the mechanism of this association, which will provide useful information for prevention and treatment of LBP among young basketball players.

Association between lower back pain and lower extremity pain among young volleyball players: A cross-sectional study

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 (6-15 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 (5.64-21.71) 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.

Risk factors for episodes of back pain in emerging adults. A systematic review

BACKGROUND AND OBJECTIVE

The transition from adolescence to adulthood is a sensitive period in life for health outcomes, including back pain. The objective was to synthesize evidence on risk factors for new episodes of back pain in emerging adults (18-29 years).

METHODS

The protocol was registered in PROSPERO (CRD42016046635). We searched Medline; EMBASE; AMED and other databases up to September 2018 for prospective cohort studies that estimated the association between risk factor(s) and self-reported back pain. Risk factors could be measured before or during the age range 18-29 years, and back pain could be measured during or after this age range, with at least 12 months between assessments. Risk factors assessed in ≥3 studies were summarized. Risk of bias was assessed using a 6-item checklist.

RESULTS

Forty-nine studies were included with more than 150 different risk factors studied. Nine studies had low risk of bias, 26 had moderate and 14 had high risk of bias. Age, sex, height, body mass index (BMI), smoking, physical activity level, a history of back pain, job satisfaction and structural imaging findings were investigated in three or more studies. History of back pain was the only risk factor consistently associated with back pain after adjustment (nine studies).

CONCLUSION

There is moderate quality evidence that a history of back pain is a risk factor for back pain. There are inconsistent associations for age, sex, height, BMI, smoking and activity level. No associations were found between job satisfaction and structural imaging findings and back pain.

SIGNIFICANCE

Emerging adulthood is a transitional period of life with changes in life style, potentially influencing future musculoskeletal health. This systematic review included 49 articles evaluating more than 150 potential risk factors for back pain, one of the most prevalent musculoskeletal disorders. No consistent results were found for life style factors such as physical activity level or BMI, both highlighted as important risk factors in previous literature. Importantly, a previous episode of back pain was a consistent risk factor for a new episode of back pain across several studies, and further investigation of risk factors for the first back pain episode is needed.

Correction of leg-length discrepancy among meat cutters with low back pain: a randomized controlled trial

Background

The etiology of non-specific low back pain (LBP) is complex and not well understood. LBP is common and causes a remarkable health burden worldwide. Leg-length discrepancy (LLD) is potentially a risk factor for development of LBP, although this relationship has been questioned. Yet only one randomized controlled study (RCT) has been performed. The objective of our study was to evaluate the effect of insoles with leg-length discrepancy (LLD) correction compared to insoles without LLD correction among meat cutters in a RCT-design.

Methods

The study population consisted 387 meat cutters who were over 35 years old and had been working 10 years or more. The LLD measurement was done by a laser ultrasound technique. All workers with an LLD of at least 5 mm and an LBP intensity of at least 2 on a 10-cm Visual Analog Scale were eligible. The LLD of all the participants in the intervention group was corrected 70%, which means that if the LLD was for example 10 mm the correction was 7 mm. The insoles were used at work for eight hours per day. The control group had insoles without LLD correction. The primary outcome was between-group difference in LBP intensity. Secondary outcomes included sciatic pain intensity, disability (Roland Morris), RAND-36, the Oswestry Disability Index, physician visits and days on sick leave over the first year. We used a repeated measures regression analysis with adjustments for age, gender and BMI. The hurdle model was used for days on sick leave.

Results

In all, 169 workers were invited and 114 (67%) responded. Of them, 42 were eligible and were randomized to the intervention (n = 20) or control group (n = 22). The workers in the intervention group had a higher improvement in LBP intensity (− 2.6; 95% confidence intervals − 3.7 – − 1.4), intensity of sciatic pain (− 2.3; − 3.4 – − 1.07) and RAND-36 physical functioning (9.6; 1.6–17.6) and a lesser likelihood of sick leaves (OR -3.7; − 7.2 - -0.2).

Conclusions

Correction of LLD with insoles was an effective intervention among workers with LBP and a standing job.

Trial registration

ISRCTN11898558. Registration date 11. Feb 2011. BioMed Central Ltd.

Knee pain is associated with lower back pain in young baseball players: a cross-sectional study

PURPOSE

Considerable research has focused on shoulder and elbow injuries among baseball players; however, although lumbar spine and knee injuries are commonly experienced, they are less frequently studied. During common motions in baseball, such as throwing, hitting, and running, energy is transferred from the lower extremities through the lower back to the upper body. Lower extremity pain, as well as lower back pain (LBP), can disrupt the kinematic chain, and it is important to understand the association between lower extremity complaints and LBP. The purpose of this study was to elucidate the association between knee pain and LBP among young baseball players.

METHODS

A cross-sectional study was conducted with young baseball players (aged 6-15 years, n = 1,609) using a self-reported questionnaire. Multivariate logistic regression models were used for analyses. Variables considered in the models were sex, age, body mass index, team levels, number of days of training per week, number of hours in practice per day on weekdays and weekend, frequency of participation in games, practice intensity, and player position.

RESULTS

The point prevalence of LBP and knee pain was 8.4% and 13.1%, respectively. Knee pain was significantly associated with LBP. Using the absence of knee pain as a reference, the adjusted odds ratio (95% confidence interval) for LBP was 5.83 (3.93-8.65) (p < 0.001) in the presence of knee pain.

CONCLUSIONS

Knee pain was associated with LBP among young baseball players. Clinicians should pay attention to knee complaints to prevent and treat LBP among young baseball players.

LEVEL OF EVIDENCE

III.

Lumbar Spine Injuries in National Collegiate Athletic Association Athletes: A 6-Season Epidemiological Study

Background:

Lumbar spine injuries in National Collegiate Athletic Association (NCAA) athletes have not been well studied.

Purpose:

To describe the epidemiology of lumbar spine injuries in NCAA athletes during the 2009/2010 through 2014/2015 academic years utilizing the NCAA Injury Surveillance Program (ISP).

Study Design:

Descriptive epidemiology study.

Methods:

A voluntary convenience sample of NCAA varsity teams from 25 sports was examined. Mechanism of injury, injury recurrence, and time lost from sport were recorded. Injury rates were calculated as the number of injuries divided by the total number of athlete-exposures (AEs). AEs were defined as any student participation in 1 NCAA-sanctioned practice or competition. Injury rate ratios and injury proportion ratios were calculated to compare the rates within and between sports by event type, season, patient sex, mechanism, injury recurrence, and time lost from sport. Comparisons between sexes were made utilizing data that had both male and female samples.

Results:

An estimated 37,435 lumbar spine injuries were identified. The overall rate of injuries was 6.01 per 1000 AEs. The rate of injuries was 4.94 per 1000 AEs in men compared with 3.94 per 1000 AEs in women for sex-comparable sports. Men were 1.25 times more likely than women to suffer a lumbar spine injury. Men’s football (24.62 injuries/1000 AEs) and women’s gymnastics (11.46 injuries/1000 AEs) had the highest rates of lumbar spine injuries. Athletes were 1.83 and 3.71 times more likely to sustain a lumbar spine injury during the preseason than the regular season or postseason, respectively. Noncontact was the most common mechanism of injury (38%). Injury recurrence was most common in men’s outdoor track (58%). Most injuries resulted in less than 24 hours of time loss from event participation (61%).

Conclusion:

The rate of lumbar spine injuries was high in NCAA athletes, and injuries commonly recurred (20%). In general, men were more likely to sustain a lumbar spine injury compared with women. Higher injury rates occurred during competition and via a noncontact mechanism of injury. In addition to prevention programs, reconditioning programs should be considered to prevent these injuries.

Diaphragm Contractility in Individuals with Chronic Ankle Instability

INTRODUCTION/PURPOSE

Previous investigations have identified impaired trunk and postural stability in individuals with chronic ankle instability (CAI). The diaphragm muscle contributes to trunk and postural stability by modulating the intra-abdominal pressure. A potential mechanism that could help to explain trunk and postural stability deficits may be related to altered diaphragm function due to supraspinal sensorimotor changes with CAI. The purpose of this study was to examine the diaphragm contractility in individuals with CAI and healthy controls.

METHODS

Twenty-seven participants with self-reported CAI and 28 healthy control participants volunteered. A portable ultrasound unit was used to visualize and measure the right and left hemidiaphragm thickness at the end of resting inspiration and expiration in supine while breathing quietly. The diaphragm movement was imaged and recorded on B-mode ultrasonography. The degree of diaphragm contractility was calculated from the mean of three images from the end of resting inspiration and expiration. Independent t-tests were used to compare the degree of diaphragm thickness of right and left sides between the CAI and the control groups.

RESULTS

The CAI group had a smaller degree of left hemidiaphragm contractility compared with the control group (P = 0.03). There was no between-group difference in other diaphragm variables.

CONCLUSION

Individuals with CAI appear to have altered diaphragm contractility, which may be an illustration of diaphragm dysfunction and central nervous system changes in CAI population. The association between CAI and altered diaphragm contractility provides clinicians a more comprehensive awareness of proximal impairments associated with CAI. Future investigation is needed to determine whether altered contractility of the diaphragm contributes to functional impairments, activity limitations, and participant restrictions commonly observed in patients with CAI.

The effects of exercise using an ergometer with swaying saddle on chronic lower back pain

[Purpose] This study aims to investigate the effects of exercise using an ergometer with swaying saddle on chronic lower back pain. [Subjects and Methods] Thirty-three normal adults (university students) with chronic lower back pain were randomly recruited. The flexibility and strength of muscles were measured before and after an 8-week intervention. Belly-bike, an ergometer with a swaying saddle, was used. The duration of intervention was 30 minutes a day, 3 times a week. To measure the level of pain, visual analogue scale (VAS) and Korean Oswestry Disability Index were used. In addition, flexibility tests such as straight leg raising and forward reaching test in the long sitting posture were used to confirm back muscle shortness. Activations of the erector spinae muscle, gluteus medius muscle, rectus femoris muscle, and vastus lateralis muscle were also measured by electromyography before and after the intervention. Electromyography of muscles around the pelvis was performed and functional tests were conducted. [Results] The flexibility and strength of the muscles significantly increased post-intervention. Functional test scores for the forward reaching test and straight leg raising test significantly improved in the Belly-bike group. [Conclusion] The results show that exercise using the Belly-bike could be effective in reducing lower back pain.

Adding Psychosocial Factors Does Not Improve Predictive Models for People With Spinal Pain Enough to Warrant Extensive Screening for Them at Baseline

BACKGROUND

Chiropractors throughout the world by and large focus on patients with musculoskeletal complaints who are generally in good health. Currently, it is widely accepted that neck pain and low back pain are best understood as biopsychosocial phenomena.

OBJECTIVE

The purpose of this study was to determine whether certain psychosocial factors provide added value for predicting recovery.

DESIGN

This was a prospective, multicenter, chiropractic, practice-based cohort study in Belgium and the Netherlands.

METHODS

A total of 917 participants, 326 with neck pain and 591 with low back pain, completed self-administered questionnaires at baseline and at 3, 6, and 12 months. They provided information on several demographic, biomedical, and psychosocial variables. Lasting perceived recovery was used as the outcome measure, that is, recovery at all follow-up assessments from 3 months on. Twenty-seven potential predictors of outcome were used to build the predictive model. Stepwise, backward generalized estimating equation regression models were used to take into account the clustering of participants within practices. For assessment of the added value of psychosocial variables, 2 model fit indexes were compared.

RESULTS

After the addition of psychosocial variables, predictors in the final model for neck pain included occupational status, body mass index, duration of complaints, previous treatment, and participant expectations (the model fit was marginally improved from 0.684 to 0.695 for the area under the curve and from 65.0% to 66.1% for the percentage correctly predicted). In the final model for low back pain, the selected predictors included country of treatment, age, duration of complaints, previous imaging, and somatization (the area under the curve changed from 0.669 to 0.715, and the percentage correctly predicted changed from 68.6% to 69.5%). Only a minority of participants had high scores on psychological variables.

LIMITATIONS

The reliability and validity of lasting recovery as an outcome measure have not been tested. The cohort needs to be seen as a convenience sample. Selection bias, therefore, not be ruled out. There are no indications, however, that patients with complex psychosocial profiles were excluded from this study.

CONCLUSIONS

Psychosocial variables provided little added value for predicting outcome in people who had neck pain or low back pain and sought chiropractic care. Therefore, chiropractors should not screen extensively for them at baseline. With regard to the identification of the small subgroup of people with high scores on psychosocial variables and a high risk for chronic pain, further investigation is needed.

Risk factors for back pain in marines; a prospective cohort study

Background

It is recognised that back pain (BP) is a debilitating medical problem in the soldier community, which limits operational readiness as well as work ability. As such, identification of risk factors is a necessity for effective preventive actions, but also regarded as important from a safety perspective. The aim of this prospective cohort study was therefore to identify risk factors for back pain and BP limiting work ability in active duty marines within a 6 and 12-month period.

Methods

Demographic characteristics, health-related factors and occupational exposure information, as gathered from questionnaires, as well as clinical test of movement control among 137 Swedish marines were regressed with multivariable logistic regressions, and strength of associations was presented as odds ratio (OR) with 95 % confidence intervals (CI). BP within 6 and 12 months were used as primary outcomes, whereas BP limiting work ability within 6 and 12 months served as secondary outcomes.

Results

Previous BP and tall body height (≥1.86 m) emerged as risk factors for back pain within 6 months (OR 2.99, 95 % CI 1.22–7.30; OR 2.81, 95 % CI 1.16– 6.84, respectively), and 12 months (OR 6.75, 95 % CI 2.30–19.80; 2.75, 95 % CI 1.21–6.29, respectively). Previous BP was also identified as risk factor for BP limiting work ability within 12 months (OR 6.64, 95 % CI 1.78–24.78), and tall body height emerged as a risk within both six (OR 4.30, 95 % CI 1.31–14.13) and 12 months (OR 4.55, 95 % CI 1.53–13.57) from baseline.

Conclusions

Marines with a history of BP are at risk of further BP episodes, which, thus, emphasise the importance of early BP preventive actions. Tall body height also emerged as an important risk which may reflect that personal equipment and work tasks are not adapted for the tallest marines. While this should be considered when introducing new work equipment, further studies are warranted to clarify the underlying mechanism of this association.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1172-y) contains supplementary material, which is available to authorized users.

Low Back Pain in Athletes Is Associated with General and Sport Specific Risk Factors: A Comprehensive Review of Longitudinal Studies

We aimed to examine systematically the available evidence on risk factors of low back pain (LBP) in athletes. We performed search without language restriction in PubMed, Ovid, Google Scholar, Scopus, and CINAHL. Longitudinal studies that examined possible risk factors of LBP in athletes were included in this systematic review. Based on methodological quality of studies, a best-evidence synthesis was conducted. Seven longitudinal studies were included, four of which had high methodological quality. Results showed that previous LBP, decreased lumbar flexion, and decreased lumbar extension are positively associated with LBP. There was moderate evidence for hip flexor tightness and high body weight as a risk factor. We found insufficient evidence for association between forward bending, previous injury, and amount of training per week, active years, age, and sex with LBP. In conclusion this study would provide a list of risk factors for LBP in athletes, though it showed a strong evidence for only a few including decrease lumbar flexion or extension, previous LBP, and high body weight. This review indicated a high heterogeneity of study characteristics including assessed risk factors and statistical techniques might limit the quality of evidence.

Pelvic and Spinal Motion During Walking in Persons With Transfemoral Amputation With and Without Low Back Pain

OBJECTIVE

Low back pain (LBP) is prevalent in people with transfemoral amputation (TFA), imposing significant disability. Yet, limited data exist describing spine kinematics in people with and without LBP despite the suggestion that gait adaptations required to walk with a prosthesis may be associated or causative of LBP. Hence, the purpose of this study was to determine if there were any differences in pelvic and spinal kinematics in persons with TFA with and without LBP.

DESIGN

With the use of a lower body model combined with a regional spine model, pelvic, lumbar, and thoracic kinematics were recorded while walking and compared for participants with TFA with (n = 12) and without (n = 11) self-reported LBP.

RESULTS

Opposite patterns of motion were observed between groups in sagittal and transverse lumbar kinematics but inferential analysis using the χ test was unable to confirm that these differing patterns were independently related to LBP.

CONCLUSIONS

For community ambulators with TFA who report low levels of LBP, differences in lumbar and thoracic motion do not seem to be independently related to LBP. Results may not generalize to those with higher levels of LBP and associated disability.

Low back and lower-limb muscle performance in male and female recreational runners with chronic low back pain

STUDY DESIGN

Controlled laboratory study, cross-sectional.

OBJECTIVE

To compare lumbar extensor muscle fatigability, lumbar stabilizing muscle activation, and lower-limb strength between male and female runners with chronic low back pain (LBP) and healthy runners.

BACKGROUND

Little is known about muscle performance in runners with chronic LBP.

METHODS

Eighteen recreational runners with chronic LBP (9 men, 9 women; mean age, 27.8 years) and 18 healthy recreational runners (9 men, 9 women; mean age, 24.6 years) were recruited. The median frequency slopes for bilateral iliocostalis and longissimus were calculated from electromyographic signals captured during a 2-minute Sorensen test. The thickness changes of the transversus abdominis and lumbar multifidus between resting and contraction were measured using an ultrasound scanner. Peak concentric torques of the bilateral hip extensors, hip abductors, and knee extensors were measured using an isokinetic dynamometer at 60°/s. The average values for both sides were used for statistical analysis.

RESULTS

When averaged across sexes, peak knee extensor torque was 12.2% lower in the LBP group compared to the healthy group (mean difference, 0.29 Nm/kg; 95% confidence interval: 0.06, 0.53; P = .016). Male runners with chronic LBP exhibited smaller lumbar multifidus thickness changes compared to healthy male runners (mean difference, 0.13 cm; 95% confidence interval: 0.01, 0.25; P = .033). No other group differences were observed.

CONCLUSION

Runners with chronic LBP exhibited diminished knee extensor strength compared to healthy runners. Male runners with chronic LBP demonstrated additional deficits in lumbar multifidus activation.

Leg-length discrepancy is associated with low back pain among those who must stand while working

Background

Some studies suggest that leg length discrepancy (LLD) is associated with low back pain (LBP) but many have not found such an association leading to conflicting evidence on the role of LLD in LBP.

Methods

The study population consisted of meat cutters with a standing job and customer service workers with a sedentary job from Atria Suomi Ltd (Nurmo, Finland) who were at least 35 years old and had been working in their jobs for at least 10 years. Leg length of each participant was measured with a laser range meter fixed in a rod, which was holding the scanning head of the ultrasound apparatus. Association of the intensity of LBP (10-cm Visual Analog Scale) with LLD was analysed by linear regression model, while the hurdle model was used in analysing the association of number of days with LBP and days on sick leave during the past year. Associations were adjusted by gender, age, BMI, smoking, depressive feelings and type of work (standing or sedentary job).

Results

The final study population consisted of 114 meat cutters (26 females and 88 males) and 34 customer service workers (30 females and four males). Forty-nine percent of the meat cutters and 44% of the customer service workers had LLD of at least 6 mm, while 16% and 15%, respectively, had LLD of at least 11 mm. In the whole study population, LLD of 6 mm or more was associated with higher intensity of LBP and number of days with LBP. In the stratified analysis, both intensity of LBP and number of days of LBP were associated with LLD among meat cutters but not among customer service workers. The sick leaves during past year were slightly longer among those with LLD 10 mm or more, but the differences were not statistically significant.

Conclusions

LLD, measured with a laser range meter, was associated with intensity of LBP and self-reported days with LBP during the past year among meat cutters engaged in standing work.

Trial registration

ISRCTN11898558 - The role of leg length discrepancy in low back pain.

An exploratory examination of the association between altered lumbar motor control, joint mobility and low back pain in athletes

Background:

Low back pain (LBP) is a common cause of lost playing time and can be a challenging clinical condition in competitive athletes. LBP in athletes may be associated with joint and ligamentous hypermobility and impairments in activation and coordination of the trunk musculature, however there is limited research in this area.

Objectives:

To determine if there is an association between altered lumbar motor control, joint mobility and low back pain (LBP) in a sample of athletes.

Materials and Methods:

Fifteen athletes with LBP were matched by age, gender and body mass index (BMI) with controls without LBP. Athletes completed a questionnaire with questions pertaining to demographics, activity level, medical history, need to self-manipulate their spine, pain intensity and location. Flexibility and lumbar motor control were assessed using: active and passive straight leg raise, lumbar range of motion (ROM), hip internal rotation ROM (HIR), Beighton ligamentous laxity scale, prone instability test (PIT), observation of lumbar aberrant movements, double leg lowering and Trendelenburg tests. Descriptive statistics were compiled and the chi square test was used to analyze results.

Results:

Descriptive statistics showed that 40% of athletes with LBP exhibited aberrant movements (AM), compared to 6% without LBP. 66% of athletes with LBP reported frequently self-manipulating their spine compared to 40% without LBP. No significant differences in motor control tests were found between groups. Athletes with LBP tended to have less lumbar flexion (63 ± 11°) compared to those without LBP (66 ± 13°). Chi-Square tests revealed that the AM were more likely to be present in athletes with LBP than those without (X2 = 4.66, P = 0.03).

Conclusions:

The presence of aberrant movement patterns is a significant clinical finding and associated with LBP in athletes.

The hip-spine connection: understanding its importance in the treatment of hip pathology

EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Discuss the kinematic relationship between the hip and lumbar spine. 2. Explain the innervation of the hip and lumbar spine and how they relate to one another. 3. Recognize the effect of hip disease on the lumbar spine in an athletic population, prior to the onset of degenerative changes. 4. Describe an algorithm for diagnosis and treatment of patients who present with concomitant hip and lumbar spine pain. The hip and lumbar spine are closely related and can create similar patterns of pain and dysfunction. Diagnosis and treatment of hip and spine-related conditions can be challenging due to symptom overlap. Successful evaluation and treatment of hip and lumbar spine conditions requires a thorough understanding the hip-spine connection. Historically the hip-spine connection has been considered in the context of arthrosis; however, the hip-spine connection also needs to be considered in a younger athletic population. The purpose of this review is to describe the hip-spine connection, discuss the clinical implications of this connection, and offer an approach to diagnosis and treatment.

Lower extremity fatigue, sex, and landing performance in a population with recurrent low back pain

CONTEXT

Low back pain and lower extremity injuries affect athletes of all ages. Previous authors have linked a history of low back pain with lower extremity injuries. Fatigue is a risk factor for lower extremity injuries, some of which are known to affect female athletes more often than their male counterparts.

OBJECTIVE

To determine the effects of lower extremity fatigue and sex on knee mechanics, neuromuscular control, and ground reaction force during landing in people with recurrent low back pain (LBP).

DESIGN

Cross-sectional study.

SETTING

A clinical biomechanics laboratory.

PATIENTS OR OTHER PARTICIPANTS

Thirty-three young adults with recurrent LBP but without current symptoms.

INTERVENTION(S)

Fatigue was induced using a submaximal free-weight squat protocol with 15% body weight until task failure was achieved.

MAIN OUTCOME MEASURE(S)

Three-dimensional knee motion, knee and ankle moments, ground reaction force, and trunk and lower extremity muscle-activity measurements were collected during 0.30-m drop vertical-jump landings.

RESULTS

Fatigue altered landing mechanics, with differences in landing performance between sexes. Women tended to have greater knee-flexion angle at initial contact, greater maximum knee internal-rotation angle, greater maximum knee-flexion moment, smaller knee-adduction moment, smaller ankle-inversion moment, smaller ground reaction force impact, and earlier multifidus activation. In men and women, fatigue produced a smaller knee-abduction angle at initial contact, greater maximum knee-flexion moment, and delays in semitendinosus, multifidus, gluteus maximus, and rectus femoris activation.

CONCLUSIONS

Our results provide evidence that during a fatigued 0.30-m landing sequence, women who suffered from recurrent LBP landed differently than did men with recurrent LBP, which may increase women's exposure to biomechanical factors that can contribute to lower extremity injury.

Alterations in neuromuscular control at the knee in individuals with chronic ankle instability

CONTEXT

Few authors have assessed neuromuscular knee-stabilization strategies in individuals with chronic ankle instability (CAI) during functional activities.

OBJECTIVE

To investigate the influence of CAI on neuromuscular characteristics around the knee during a stop-jump task.

DESIGN

Case-control study.

SETTING

Research laboratory. Participants or Other Participants: A total of 19 participants with self-reported unilateral CAI and 19 healthy control participants volunteered for this study.

INTERVENTION(S)

Participants performed double-legged, vertical stop-jump tasks onto a force plate, and we measured muscle activation around the knee of each limb.

MAIN OUTCOME MEASURE(S)

We calculated the integrated electromyography for the vastus medialis oblique, vastus lateralis, medial hamstrings, and lateral hamstrings muscles during the 100 ms before and after initial foot contacts with the force plate and normalized by the ensemble peak electromyographic value. Knee sagittal-plane kinematics were also analyzed during a stop-jump task.

RESULTS

Compared with control participants, the CAI group demonstrated greater prelanding integrated electromyographic activity of the vastus medialis oblique (CAI = 52.28 ± 11.25%·ms, control = 43.90 ± 10.13%·ms, t36 = 2.41, P = .021, effect size = 0.78, 95% confidence interval = 0.11, 1.43) and less knee-flexion angle at the point of initial foot contact (CAI = 7.81° ± 8.27°, control = 14.09° ± 8.7°, t36 = -2.28, P = .029, effect size = -0.74, 95% confidence interval = -1.38, -0.07) and at 100 ms post-initial foot contact (CAI = 51.36° ± 5.29°, control = 58.66° ± 7.66°, t36 = -3.42, P = .002, effect size = -1.11, 95% confidence interval = -1.77, -0.40). No significant results were noted for the other electromyographic measures.

CONCLUSIONS

We found altered feed-forward patterns of the vastus medialis oblique and altered postlanding knee sagittal-plane kinematics in the CAI group. These observations may provide insight regarding sensorimotor characteristics that may be associated with CAI.

The relationship between the piriformis muscle, low back pain, lower limb injuries and motor control training among elite football players

OBJECTIVES

Australian Football League (AFL) players have a high incidence of back injuries. Motor control training to increase lumbopelvic neuromuscular control has been effective in reducing low back pain (LBP) and lower limb injuries in elite athletes. Control of pelvic and femoral alignment during functional activity involves the piriformis muscle. This study investigated (a) the effect of motor control training on piriformis muscle size in AFL players, with and without LBP, during the playing season, and (b) whether there is a relationship between lower limb injury and piriformis muscle size.

DESIGN

Stepped-wedge intervention.

METHODS

46 AFL players participated in a motor control training programme consisting of two 30min sessions per week over 7-8 weeks, delivered across the season as a randomised 3 group single-blinded stepped-wedge design. Assessment of piriformis muscle cross-sectional area (CSA) involved magnetic resonance imaging (MRI) at 3 time points during the season. Assessment of LBP consisted of player interview and physical examination. Injury data were obtained from club records.

RESULTS

An interaction effect for Time, Intervention Group and LBP group (F=3.7, p=0.03) was found. Piriformis muscle CSA showed significant increases between Times 1 and 2 (F=4.24, p=0.046), and Times 2 and 3 (F=8.59, p=0.006). Players with a smaller increase in piriformis muscle CSA across the season had higher odds of sustaining an injury (OR=1.08).

CONCLUSIONS

Piriformis muscle size increases across the season in elite AFL players and is affected by the presence of LBP and lower limb injury. Motor control training positively affects piriformis muscle size in players with LBP.

Prediction of core and lower extremity strains and sprains in collegiate football players: a preliminary study

CONTEXT

Poor core stability is believed to increase vulnerability to uncontrolled joint displacements throughout the kinetic chain between the foot and the lumbar spine.

OBJECTIVE

To assess the value of preparticipation measurements as predictors of core or lower extremity strains or sprains in collegiate football players.

DESIGN

Cohort study.

SETTING

National Collegiate Athletic Association Division I Football Championship Subdivision football program.

PATIENTS OR OTHER PARTICIPANTS

All team members who were present for a mandatory physical examination on the day before preseason practice sessions began (n = 83).

MAIN OUTCOME MEASURE(S)

Preparticipation administration of surveys to assess low back, knee, and ankle function; documentation of knee and ankle injury history; determination of body mass index; 4 different assessments of core muscle endurance; and measurement of step-test recovery heart rate. All injuries were documented throughout the preseason practice period and 11-game season. Receiver operating characteristic analysis and logistic regression analysis were used to identify dichotomized predictive factors that best discriminated injured from uninjured status. The 75th and 50th percentiles were evaluated as alternative cutpoints for dichotomization of injury predictors.

RESULTS

Players with ≥2 of 3 potentially modifiable risk factors related to core function had 2 times greater risk for injury than those with <2 factors (95% confidence interval = 1.27, 4.22), and adding a high level of exposure to game conditions increased the injury risk to 3 times greater (95% confidence interval = 1.95, 4.98). Prediction models that used the 75th and 50th percentile cutpoints yielded results that were very similar to those for the model that used receiver operating characteristic-derived cutpoints.

CONCLUSIONS

Low back dysfunction and suboptimal endurance of the core musculature appear to be important modifiable football injury risk factors that can be identified on preparticipation screening. These predictors need to be assessed in a prospective manner with a larger sample of collegiate football players.

The myth of core stability

The principle of core stability has gained wide acceptance in training for the prevention of injury and as a treatment modality for rehabilitation of various musculoskeletal conditions in particular of the lower back. There has been surprisingly little criticism of this approach up to date. This article re-examines the original findings and the principles of core stability/spinal stabilisation approaches and how well they fare within the wider knowledge of motor control, prevention of injury and rehabilitation of neuromuscular and musculoskeletal systems following injury.

Axial back pain in the athlete: pathophysiology and approach to rehabilitation

Back pain in athletes is common. Proper management of an athlete with back pain who is trying to return to competition must take into account the probable biomechanical contributors and incorporate these into a comprehensive rehabilitation program that moves steadily forward towards defined goals. This study will attempt to discuss pathological commonalities of low-back pain in athletes and how these can be applied to an evidence-based rehabilitation approach.

Optimizing performance by improving core stability and core strength

Core stability and core strength have been subject to research since the early 1980s. Research has highlighted benefits of training these processes for people with back pain and for carrying out everyday activities. However, less research has been performed on the benefits of core training for elite athletes and how this training should be carried out to optimize sporting performance. Many elite athletes undertake core stability and core strength training as part of their training programme, despite contradictory findings and conclusions as to their efficacy. This is mainly due to the lack of a gold standard method for measuring core stability and strength when performing everyday tasks and sporting movements. A further confounding factor is that because of the differing demands on the core musculature during everyday activities (low load, slow movements) and sporting activities (high load, resisted, dynamic movements), research performed in the rehabilitation sector cannot be applied to the sporting environment and, subsequently, data regarding core training programmes and their effectiveness on sporting performance are lacking. There are many articles in the literature that promote core training programmes and exercises for performance enhancement without providing a strong scientific rationale of their effectiveness, especially in the sporting sector. In the rehabilitation sector, improvements in lower back injuries have been reported by improving core stability. Few studies have observed any performance enhancement in sporting activities despite observing improvements in core stability and core strength following a core training programme. A clearer understanding of the roles that specific muscles have during core stability and core strength exercises would enable more functional training programmes to be implemented, which may result in a more effective transfer of these skills to actual sporting activities.

The effects of stochastic resonance stimulation on spine proprioception and postural control in chronic low back pain patients

STUDY DESIGN

Spine proprioception and postural control in unstable sitting were compared in 18 chronic low back pain patients using a repeated measures design.

OBJECTIVE

The study objective was to determine if stochastic resonance (SR) stimulation of the paraspinal muscles improves spine proprioception and trunk postural control.

SUMMARY OF BACKGROUND DATA

Decreased spine proprioception and larger postural sway have been found in low back pain patients, although several studies have also shown no differences in spine proprioception.

METHODS

Spine proprioception, measuring subjects' sensitivity to change in position, was assessed in 3 orthopaedic planes. Postural control was assessed using an unstable seat with a hemisphere attached to the bottom. Subjects balanced with eyes closed on the most challenging size hemisphere they could manage while center-of-pressure was recorded with a force plate beneath the seat. Both tasks were performed with SR stimulation randomized at 0%, 25%, 50%, and 90% intensity levels.

RESULTS

No significant differences in spine proprioception were observed between SR stimulation levels for any of the 3 orthopaedic planes. SR stimulation significantly improved postural control, but only in the lateral plane. No differences in postural control were observed between stimulation levels 25%, 50%, and 90% in the lateral plane. There was no correlation between spine proprioception and postural control.

CONCLUSION

Results suggest that SR stimulation to the paraspinal muscles can improve postural control; however, this improvement cannot be attributed to improved spine proprioception based on the current study. People with compromised neuromuscular control or those exposed to unstable environments may benefit from SR stimulation.

The importance of sensory-motor control in providing core stability: implications for measurement and training

Although the hip musculature is found to be very important in connecting the core to the lower extremities and in transferring forces from and to the core, it is proposed to leave the hip musculature out of consideration when talking about the concept of core stability. A low level of co-contraction of the trunk muscles is important for core stability. It provides a level of stiffness, which gives sufficient stability against minor perturbations. Next to this stiffness, direction-specific muscle reflex responses are also important in providing core stability, particularly when encountering sudden perturbations. It appears that most trunk muscles, both the local and global stabilization system, must work coherently to achieve core stability. The contributions of the various trunk muscles depend on the task being performed. In the search for a precise balance between the amount of stability and mobility, the role of sensory-motor control is much more important than the role of strength or endurance of the trunk muscles. The CNS creates a stable foundation for movement of the extremities through co-contraction of particular muscles. Appropriate muscle recruitment and timing is extremely important in providing core stability. No clear evidence has been found for a positive relationship between core stability and physical performance and more research in this area is needed. On the other hand, with respect to the relationship between core stability and injury, several studies have found an association between a decreased stability and a higher risk of sustaining a low back or knee injury. Subjects with such injuries have been shown to demonstrate impaired postural control, delayed muscle reflex responses following sudden trunk unloading and abnormal trunk muscle recruitment patterns. In addition, various relationships have been demonstrated between core stability, balance performance and activation characteristics of the trunk muscles. Most importantly, a significant correlation was found between poor balance performance in a sitting balance task and delayed firing of the trunk muscles during sudden perturbation. It was suggested that both phenomena are caused by proprioceptive deficits. The importance of sensory-motor control has implications for the development of measurement and training protocols. It has been shown that challenging propriocepsis during training activities, for example, by making use of unstable surfaces, leads to increased demands on trunk muscles, thereby improving core stability and balance. Various tests to directly or indirectly measure neuromuscular control and coordination have been developed and are discussed in the present article. Sitting balance performance and trunk muscle response times may be good indicators of core stability. In light of this, it would be interesting to quantify core stability using a sitting balance task, for example by making use of accelerometry. Further research is required to develop training programmes and evaluation methods that are suitable for various target groups.