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

The Running Readiness Scale and Injury in Collegiate Track and Field and Cross Country Athletes

CONTEXT

Track and field and cross country athletes experience high rates of lower extremity injuries. The Running Readiness Scale (RRS) may help determine which athletes have a higher likelihood of lower extremity injury.

OBJECTIVE

To determine if RRS performance at the start of the season was related to the likelihood of experiencing a lower extremity injury during the subsequent track and field or cross country season.

DESIGN

Prospective cohort study.

SETTING

University.

PATIENTS OR OTHER PARTICIPANTS

One hundred thirteen National Collegiate Athletic Association Division III track and field athletes in running, jumping, and vaulting events and cross country runners (50 women and 63 men, age = 19.9 ± 1.3 years [mean ± SD]).

MAIN OUTCOME MEASURE(S)

Athletes were assessed on RRS tasks (double-leg hopping, plank, step-ups, single-leg squats, and wall sit) at the start of their season and were then observed by team athletic trainers during the season for occurrence of lower extremity injuries that resulted in missing 1 or more practices or meets. Adjusted odds ratios and 95% confidence intervals were used to assess the likelihood of lower extremity injury.

RESULTS

Thirty-seven athletes (32.7%) experienced a lower extremity injury. Athletes scoring ≤3 on the RRS were almost 5 times more likely to experience a lower extremity injury (adjusted odds ratios = 4.8; 95% confidence interval: 2.1, 11.3) than athletes scoring ≥4. Athletes who failed the double-leg hop or wall sit task were more likely to experience a lower extremity injury (P < .05).

CONCLUSIONS

Track and field and cross country athletes with RRS scores of ≤3 had a higher likelihood of lower extremity injury than those with scores of ≥4.

Low Back Pain or Injury Before Collegiate Athletics, a Potential Risk Factor for Noncontact Athletic Injuries

CONTEXT

Surrounding the predictive value of clinical measurements and assessments for future athletic injury, most researchers have not differentiated between contact and noncontact injuries.

OBJECTIVES

We assessed the association between clinical measures and questionnaire data collected before sport participation and the incidence of noncontact lower extremity (LE) injuries among Division III collegiate athletes.

DESIGN

Prospective cohort study.

SETTING

University setting, National Collegiate Athletic Association Division III.

PATIENTS OR OTHER PARTICIPANTS

Here, 488 Division III freshmen athletes were recruited to participate in the study during their preseason physical examinations.

MAIN OUTCOME MEASURE(S)

Prospective incidence of noncontact LE injury. Athletes completed questionnaires to collect demographics and musculoskeletal pain history. Clinical tests, performed by trained examiners, included hip provocative tests, visual appraisal of a single-leg squat to identify dynamic knee valgus, and hip range of motion. Injury surveillance for each athlete's collegiate career was performed. The athletic training department documented each athlete-reported new onset injury and documented the injury location, type, and outcome (days lost, surgery performed). Univariable generalized estimating equation models were used to analyze the relationship between each clinical measure and the first occurrence of noncontact LE injury. An exchangeable correlation structure was used to account for repeated measurements within athletes (right and left limbs).

RESULTS

Of the 488 athletes, 369 athletes (75%) were included in the final analysis. Sixty-nine noncontact LE injuries were reported. Responding yes to, "Have you ever had pain or an injury to your low back?" was associated with an increased risk of noncontact LE, odds ratio = 1.59 (95% confidence interval = 1.03, 2.45; P = .04). No other clinical measures were associated with an increased injury risk.

CONCLUSIONS

A history of prior low back pain or injury was associated with an increased risk of sustaining a noncontact LE injury while participating in National Collegiate Athletic Association Division III athletics.

Relationship Between the Results of the Landing Error Scoring System and Trunk Muscle Thickness

Background

A landing error scoring system (LESS) is widely used to evaluate landing maneuvers. Poor landing maneuvers, such as lateral bending of the trunk, are thought to be associated with a risk of lower-extremity injury. However, no studies have examined the association between landing and trunk muscle function, which is associated with a high risk of lower-extremity injury.

Hypothesis/Purpose

This study examined whether an association exists between landing movements and a high risk of lower-extremity injury and trunk muscle function. It was hypothesized that athletes with poor activation of deep trunk muscle (transversus abdominis and internal oblique) would have lower LESS scores.

Study Design

Cross-sectional study.

Methods

The trunk muscle thickness at rest and during the plank was measured using ultrasonography. The percent of change in muscle thickness (during plank/at rest) was calculated. The LESS was measured using the Physimax. Based on the LESS scores, patients were divided into high- (LESS > 6) and low-risk (5 > LESS) groups for lower extremity injury. The relationship between the high-risk group and trunk muscle thickness was examined using a stepwise regression analysis.

Results

The high-risk group had significantly lower muscle thicknesses of the transversus abdominis (p=0.02) and transversus abdominis plus internal oblique abdominis (p=0.03) muscles during the plank. Additionally, the high-risk group showed significantly lower percent of change in muscle thickness of the internal oblique (p=0.02) and transversus abdominis plus internal oblique (p=0.01) muscles. Only the percentage of change in the thickness of the internal oblique and transverse abdominal muscles was extracted from the regression as a factor.

Conclusion

The findings indicated that athletes with landing movements and a high risk of injury, as determined based on the LESS results, had low trunk muscle function, and a relationship was observed between the change in thickness of transversus abdominis and internal oblique abdominis muscles.

Level of Evidence

3B.

Potential neurophysiological and biomechanical risk factors for sport-related back problems: A scoping review

This scoping review aims (1) to map the literature dealing with neurophysiological and biomechanical aspects of back problems in athletes in order to identify valid risk-factors for their prevention, plus (2) to identify gaps in the existing research and propose suggestions for future studies. A literature search conducted with Scopus, Web of Science, MEDLINE and Cochrane Library was completed by Elsevier, SpringerLink and Google Scholar. The main neurophysiological risk factors identified leading to back problems in athletes are neuromuscular imbalance, increased muscle fatigability, muscle dysfunction and impaired motor control, whilst biomechanical risk factors include maladaptive spinal, spinopelvic and lower limb kinematics, side-to-side imbalances in axial strength and hip rotation range of motion, spinal overloading and deficits in movement pattern. However, most studies focused on back pain in the lumbar region, whereas less attention has been paid to thoracic and cervical spine problems. The range of sports where this topic has been studied is relatively small. There is a lack of research in sports in which the core muscles are highly involved in specific movements such as lifting weights or trunk rotations. A limited number of studies include female athletes and master athletes of both genders. In addition to chronic back pain patients, it is equally important to conduct research on healthy athletes with a predisposition to spine problems. Investigators should focus their empirical work on identifying modifiable risk factors, predict which athletes are at risk for back problems, and develop personalized sport-specific assessment tools and targeted prevention strategies for them. This review was registered using the Open Science Framework Registries (https://osf.io/ha5n7).

Comparative Risk Analysis of Low Back Pain among Professional Football, Ice Hockey, and Floorball Athletes

BACKGROUND Low back pain (LBP) is a common concern among professional athletes, potentially hindering performance and career longevity. However, comparative assessments of LBP prevalence and severity across various sports remain scarce. This study aimed to evaluate the factors associated with LBP in 388 professional athletes, including football, ice hockey, and floorball players. MATERIAL AND METHODS Conducted from June 2021 to September 2022, this cross-sectional study incorporated 388 athletes from national elite clubs, including football (n=148), ice hockey (n=179), and floorball (n=61). The Oswestry Disability Index (ODI), comprising sections like pain intensity, self-care, lifting, walking, sitting, standing, sleeping, sexual life, social life, and traveling, was employed to evaluate spinal pain and disability. RESULTS The study found no significant disparities in the LBP assessment among the groups. The relative risk (OR) of LBP and disability varied among the sports: football players displayed a lower risk (OR=0.49; 95% CI 0.32-0.74, P≤0.001), while ice hockey players had a higher risk (OR=2.18; 95% CI 1.45-3.29, P≤0.001) compared to the others. In contrast, the risk for floorball players (OR=0.82; 95% CI 0.47-1.41) did not significantly deviate from that of the other two sports. CONCLUSIONS LBP prevalence stood at 42.6% for football players, 60.1% for ice hockey players, and 49.2% for floorball players. Among these, ice hockey players exhibited a 2.18-fold increased risk of developing LBP and associated disability when compared to their football and floorball counterparts.

Physiological and Biomechanical Monitoring in American Football Players: A Scoping Review

American football is the sport with the highest rates of concussion injuries. Biomedical engineering applications may support athletes in monitoring their injuries, evaluating the effectiveness of their equipment, and leading industrial research in this sport. This literature review aims to report on the applications of biomedical engineering research in American football, highlighting the main trends and gaps. The review followed the PRISMA guidelines and gathered a total of 1629 records from PubMed (n = 368), Web of Science (n = 665), and Scopus (n = 596). The records were analyzed, tabulated, and clustered in topics. In total, 112 studies were selected and divided by topic in the biomechanics of concussion (n = 55), biomechanics of footwear (n = 6), biomechanics of sport-related movements (n = 6), the aerodynamics of football and catch (n = 3), injury prediction (n = 8), heat monitoring of physiological parameters (n = 8), and monitoring of the training load (n = 25). The safety of players has fueled most of the research that has led to innovations in helmet and footwear design, as well as improvements in the understanding and prevention of injuries and heat monitoring. The other important motivator for research is the improvement of performance, which has led to the monitoring of training loads and catches, and studies on the aerodynamics of football. The main gaps found in the literature were regarding the monitoring of internal loads and the innovation of shoulder pads.

Preseason Prognostic Factors for Injuries and Match Loss in Collision Sports: A Systematic Review

This study aimed to identify which preseason factors had strong evidence of risks for physical injury during the season of collision sports including rugby, American football, and Australian rules football using qualitative synthesis. Pubmed, EMBASE, MEDLINE, SPORTDiscus, Scopus, and the Cochrane Library were reviewed. Eligibility criteria for selecting studies were: studies involving the collision sports; prospective cohort studies; and studies with outcomes of relative risks, odds ratios, and correlations between players' preseason conditions and injury during the season. The risk of bias based on the Scottish Intercollegiate Guidelines Network quality checklists for cohort studies was assessed in 57 studies. The current study identified strong evidence that 1) anthropometric characteristics (body mass index and estimated mass moment of inertia of the body around a horizontal axis through the ankle), which are calculated with weight and height; 2) physical function, in particular for the trunk and lower limb (trunk-flexion hold and wall-sit hold); and 3) Oswestry Disability Index disability, which is a patient-reported outcome measure for disability due to low back pain, were positive prognostic factors for injury during the collision sports season, regardless of playing experience.

Composite functional movement screen score predicts injuries in youth volleyball players: a prospective cohort study

We aimed to investigate whether composite Functional Movement Screen (FMS) test scores can predict musculoskeletal injuries (MSI) in youth volleyball players. 131 national young volleyball players (Males: n = 100, age = 16.5 years, height = 1.787 m, mass = 68.32 kg; Females: n = 31, age = 13.83 years, height = 1.684 m, mass = 65.12 kg) participated in this prospective cohort study. The FMS screen was performed before starting the season. MSI and exposure data were collected during the season via each team's certified athletic trainer. The mean FMS score and standard deviation for all volleyball players was 15.85 ± 3.31. A score of ≤ 14 was positive to predict MSI with specificity of 0.60 and sensitivity of 0.93. The odds ratio for (≤ 14/˃14) was 0.048. The relative risk for being injured was 3.46. Positive likelihood ratio was 2.34, and negative likelihood ratio was 0.11. The findings of this study demonstrated that an FMS score of ≤ 14 is an identifiable risk factor for injury in young volleyball players. The FMS can be used as a pre-season screening test to identify volleyball players who may be predisposed to sustaining MSI during the season ahead.

The Correlation Between the Strength of the Shoulder and Trunk Muscular Systems in Elite Adolescent Water Polo Athletes

Introduction

Water polo is a competitive team sport played in the water between two teams of seven players each. Water polo players must have swimming speed, strong abdominal and back muscles, and strong shoulder muscles to cope with this sport's special conditions. In this study, we investigate the possible association of shoulder and trunk muscle systems in adolescent water polo athletes of high demands.

Materials and methods

The research included 42 water polo players aged 14-16, who train regularly for at least five years, six times a week, and participate in national championships and national teams. The athletes were evaluated on the strength and torque of these muscular systems using the isokinetic dynamometer Biodex System 4 Pro (Biodex Medical Systems, Inc, Shirley, NY). The correlation of the results was done using the statistical package SPSS 21.

Results

The correlations revealed statistically significant differences in trunk extension in combination with the shoulder external/internal rotation ratio. Also, most of the correlations occurred between the trunk and non-dominant limb of the athletes and, more often, in the female athletes. Furthermore, for the hand grip, the male athletes showed a greater difference in strength between the dominant and the non-dominant member than female athletes. Finally, the evaluation of the trunk extension/flexion ratio and external/internal rotation ratio for the shoulder joint showed that many athletes are outside the normal range and need targeted strengthening.

Conclusion

The negative correlation coefficient between trunk extension/flexion and shoulder external/internal rotation indicates that the trunk extension mechanism helps for better internal rotation of the shoulder. Therefore, water polo players should focus on the training of the stretching mechanism of the trunk and also give weight to achieving a balance between the competing muscular systems of the trunk and the shoulder. Thus, athletes can maximize their skills and, at the same time, protect themselves from injuries.

Plank Times and Lower Extremity Overuse Injury in Collegiate Track-and-Field and Cross Country Athletes

Trunk muscle endurance has been theorized to play a role in running kinematics and lower extremity injury. However, the evidence examining the relationships between static trunk endurance tests, such as plank tests, and lower extremity injury in athletes is conflicting. The purpose of this study was to assess if collegiate cross country and track-and-field athletes with shorter pre-season prone and side plank hold times would have a higher incidence of lower extremity time-loss overuse injury during their competitive sport seasons. During the first week of their competitive season, 75 NCAA Division III uninjured collegiate cross country and track-and-field athletes (52% female; mean age 20.0 ± 1.3 years) performed three trunk endurance plank tests. Hold times for prone plank (PP), right-side plank (RSP) and left-side plank (LSP) were recorded in seconds. Athletes were followed prospectively during the season for lower extremity overuse injury that resulted in limited or missed practices or competitions. Among the athletes, 25 (33.3%) experienced a lower extremity overuse injury. There were no statistically significant mean differences or associations found between PP, RSP or LSP plank test hold times (seconds) and occurrence of lower extremity overuse injury. In isolation, plank hold times appear to have limited utility as a screening test in collegiate track-and-field and cross country athletes.

Whole-Body Reactive Agility Metrics to Identify Football Players With a Core and Lower Extremity Injury Risk

Clinical prediction models are useful in addressing several orthopedic conditions with various cohorts. American football provides a good population for attempting to predict injuries due to their relatively high injury rate. Physical performance can be assessed a variety of ways using an assortment of different tests to assess a diverse set of metrics, which may include reaction time, speed, acceleration, and deceleration. Asymmetry, the difference between right and left performance has been identified as a possible risk factor for injury. The purpose of this study was to determine the whole-body reactive agility metrics that would identify Division I football players who were at elevated risk for core, and lower extremity injuries (CLEI). This cohort study utilized 177 Division I football players with a total of 57 CLEI suffered who were baseline tested prior to the season. Single-task and dual-task whole-body reactive agility movements in lateral and diagonal direction reacting to virtual reality targets were analyzed separately. Receiver operator characteristic (ROC) analyses narrowed the 34 original predictor variables to five variables. Logistic regression analysis determined the three strongest predictors of CLEI for this cohort to be: lateral agility acceleration asymmetry, lateral flanker deceleration asymmetry, and diagonal agility reaction time average. Univariable analysis found odds ratios to range from 1.98 to 2.75 for these predictors of CLEI. ROC analysis had an area under the curve of 0.702 for any combination of two or more risk factors produced an odds ratio of 5.5 for risk of CLEI. These results suggest an asymmetry of 8-15% on two of the identified metrics or a slowed reaction time of ≥0.787 s places someone at increased risk of injury. Sixty-three percent (36/57) of the players who sustained an injury had ≥2 positive predictors In spite of the recognized limitation, these finding support the belief that whole-body reactive agility performance can identify Division I football players who are at elevated risk for CLEI.

Men and women trainers equally effective at promoting exercise adherence, self-efficacy, and fitness in women

BACKGROUND

This study examined the effect of a personal trainer's sex on self-efficacy and fitness in woman clients.

METHODS

Women (n: 28; mean ± SD; age, 41.6 ± 15.0 yrs.; height, 153.49 ± 28.11cm; BMI, 25.9 ± 6.4 kg•m-2) completed a perceptual scale of self-efficacy (BARSE) and fitness tests before and after a training program. Trainers (men and women) met one-on-one with the volunteers on a biweekly basis for 8 weeks. Univariate analyses of change scores and repeated measures analysis of variance with Fisher's LSD pairwise comparisons tested changes in dependent variables by trainer sex.

RESULTS

Significant increases were seen in (mean ± SE; change for men trainers; change for woman trainers): self-efficacy (7.3 ± 3.4; 7.3 ± 2.7%); leg press strength (18.2 ± 3.7; 16.4 ± 3.3 kg); seated row (6.1 ± 1.5; 5.3 ± 1.3 kg); muscular endurance in 60° flexion hold (20.5 ± 5.8; 24.8 ± 5.0 sec) and wall-sit (19.9 ± 6.4; 33.5 ± 5.8 sec); but not flexibility (V-sit, 7.11 ± 5.51; 4.23 ± 4.50 cm). Chest press strength significantly increased for women trainers only (2.7 ± 2.2; 5.3 ± 1.8 kg). Despite this, there were no significant differences for any variable in the change from pre-to-post based on the sex of the trainer.

CONCLUSIONS

Both men and woman-led training was effective for increasing markers of self-efficacy and fitness in woman clients.

Trunk Muscle Endurance in Individuals With and Without a History of Anterior Cruciate Ligament Reconstruction

ABSTRACT

Werner, DM and Barrios, JA. Trunk muscle endurance in individuals with and without a history of anterior cruciate ligament reconstruction. J Strength Cond Res 35(1): 118-123, 2021-Anterior cruciate ligament (ACL) rupture is one of the most common knee injuries and often leads to surgery. Second injury after an ACL reconstruction (ACLR) is a major risk after rehabilitation, and may be linked to persistent postoperative deficits in muscular strength and endurance. Trunk muscle endurance has not been well studied after ACLR. Therefore, the purpose of this study was to compare trunk endurance using the established McGill testing battery in 20 individuals who had previously undergone ACLR at least 1 year before with 20 controls matched for sex frequency, limb dominance, age, body mass index, and activity level. Four static positional holds to failure were performed in random order, with time in seconds recorded as the primary dependent variable. Mann-Whitney U tests using an alpha level of 0.05 were conducted comparing hold times for all positions between groups. Effect sizes were also calculated between groups. Deficits in trunk extension endurance were observed in the surgical group. The results of this study suggest that contemporary rehabilitation schemes after ACLR do not fully address trunk endurance deficits. Health care professionals delivering postoperative rehabilitation after ACLR may consider direct assessment of trunk endurance and targeted exercise training to address potential deficits.

The role of core stability in the development of non-contact acute lower extremity injuries in an athletic population: A prospective study

OBJECTIVES

Stability of the core is associated with lower extremity functioning. Consequently, impaired core stability might play a role in developing non-contact acute lower extremity sports injuries. The objective was to investigate components of core stability as potential risk factors for acute lower extremity injuries.

DESIGN

A cohort study was set up with a follow-up and injury registration period of 1.5 years.

PARTICIPANTS

142 male and female physical education students were included.

MAIN OUTCOME MEASURES

Measures of isometric hip and core muscular strength, endurance, proprioception and neuromuscular control of the core, and postural control were taken at the start of the study. Sports-related injury occurrence was registered during follow-up.

RESULTS

27 (19%) injuries of interest occurred during follow-up. After multivariate model building, a significant predictive effect was found for side-to-side hip abduction strength asymmetry (p = .007). The hazard of developing an acute lower extremity injury increased with 6.2% with a 1 unit increase in side-to-side strength imbalance, regardless of gender.

CONCLUSION

Hip abduction strength imbalance was determined as a risk factor for the development of non-contact, acute lower extremity injuries. Normalizing hip strength imbalances might be beneficial for injury prevention. However, further research is needed to support this claim.

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.

Limited Support for Trunk and Hip Deficits as Risk Factors for Athletic Knee Injuries: A Systematic Review With Meta-analysis and Best-Evidence Synthesis

OBJECTIVE

To determine whether neuromuscular deficits in trunk and hip-related function are risk factors for athletic knee injuries.

DESIGN

Etiology systematic review with meta-analysis.

LITERATURE SEARCH

Six online databases (MEDLINE, Web of Science, Embase, CINAHL, Scopus, and SPORTDiscus) were searched up to April 2019.

STUDY SELECTION CRITERIA

Studies assessing trunk and hip neuromuscular function as risk factors for knee injuries in healthy athletic populations were included.

DATA SYNTHESIS

Outcomes were synthesized quantitatively using meta-analysis of odds ratios, and qualitatively using best-evidence synthesis.

RESULTS

Twenty-one studies met the inclusion criteria. There was very low-certainty evidence that greater hip external rotation strength protected against knee injuries (odds ratio = 0.78; 95% confidence interval: 0.70, 0.87; P<.05). There was limited evidence that deficits in trunk proprioception and neuromuscular control, and the combination of excessive knee valgus and ipsilateral trunk angle when landing unilaterally from a jump, may be risk factors for knee injuries.

CONCLUSION

Most variables of trunk and hip function were not risk factors for injuries. Further research is required to confirm whether hip external rotation strength, trunk proprioception and neuromuscular control, and the combination of knee valgus angle and ipsilateral trunk control are risk factors for future knee injuries. J Orthop Sports Phys Ther 2020;50(9):476-489. Epub 1 Aug 2020. doi:10.2519/jospt.2020.9705.

Clinical Assessment and Thickness Changes of the Oblique and Multifidus Muscles Using a Novel Screening Tool and Exercise Program: A Randomized Controlled Trial

CONTEXT

Training and assessment of the abdominal and trunk muscles are widely used in the clinical setting. However, it is unknown what types of exercises are most effective in activation of both the global and local stabilizers in these regions.

OBJECTIVE

The purpose of this study was to establish the reliability of a novel clinical screening tool (sling screen) to assess the muscles of the abdomen and trunk. The second aim was to use the clinical screening tool and musculoskeletal ultrasound to compare the effects of a rotary-based exercise program that targets both the global and local muscles to the effects of a traditional exercise program on the activation of the abdominal and trunk muscles.

DESIGN

Double-blind, randomized controlled trial.

SETTING

Sports medicine facility.

PARTICIPANTS AND INTERVENTIONS

Thirty-one healthy participants were randomly allocated to receive a single-session rotary-based or traditional "core" exercise program.

MAIN OUTCOME MEASURES

The participants were assessed at the baseline and immediately postintervention. The primary outcome measures were muscle thickness examined by musculoskeletal ultrasound and clinical examination of muscle activation using a screening tool. The data were collected by blind assessors. Reliability and validity of a clinical screening tool (sling screen) were also assessed.

RESULTS

The analysis of the covariance tests showed a significant increase in oblique thickness for the rotary exercise group. All participants displayed a significant increase in multifidus thickness. The Wilcoxon signed-rank tests revealed a significant increase in clinical assessment scores in the rotary exercise group but not the traditional exercise group. Reliability of the sling screen ranged from moderate to good.

CONCLUSION

This clinical trial provides evidence that a rotary-based exercise program may be more effective in producing increases in oblique muscle thickness than traditional "core" exercises in young, healthy adults. The sling screen tool was able to identify these muscle thickness changes. Future studies should investigate how these results correlate to injury risk, other populations, and also how to implement the sling screen into clinical practice.

The Relationship Between Injury-Related Fear and Visuomotor Reaction Time in Individuals With a History of Anterior Cruciate Ligament Reconstruction

CONTEXT

Deficits in reaction time, decreased self-reported knee function, and elevated levels of injury-related fear have been observed in individuals who sustain anterior cruciate ligament injury. Understanding the relationship between these variables may provide the impetus to further investigate effective intervention strategies to address these deficits in individuals after anterior cruciate ligament reconstruction (ACLR).

OBJECTIVE

To examine the relationship between injury-related fear and lower-extremity visuomotor reaction time (VMRT) in individuals with a history of ACLR. A secondary purpose was to determine the relationship between self-reported knee function and lower-extremity VMRT in individuals with a history of ACLR.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PARTICIPANTS

Twenty participants between the ages of 18-35 years, with history of unilateral ACLR within the last 10 years, who injured their knee playing or training for organized or recreational sports.

MAIN OUTCOME MEASURES

Scores on the athlete fear avoidance questionnaire, the fear-avoidance beliefs questionnaire (FABQ), the knee injury and osteoarthritis outcome score, and reaction time (in seconds) on the lower-extremity VMRT task using the FitLight Trainer™, bilaterally. Spearman Rho correlations examined the relationship between the dependent variables.

RESULTS

There was a moderate positive correlation between VMRT and FABQ-total (r = .62, P < .01), FABQ-sport (r = .56, P = .01), and FABQ-physical activity (r = .64, P < .01) for the injured limb. Correlations between FABQ scores and VMRT for the uninjured limb were weak positive correlations (r = .36-.41, P > .05). Weak correlations between the osteoarthritis outcome score subscales, athlete fear avoidance questionnaire, and VMRT were observed for the injured limb (P > .05).

CONCLUSIONS

Individuals with a history of ACLR who exhibited elevated levels of injury-related fear demonstrated slower VMRT. There were no relationships between self-reported knee function and VMRT. Future research should explore interventions to address injury-related fear and VMRT in individuals after ACLR.

There Is No Relationship Between Lower Extremity Alignment During Unilateral and Bilateral Drop Jumps and the Risk of Knee or Ankle Injury: A Prospective Study

OBJECTIVE

To investigate the association between lower extremity alignment during unilateral and bilateral drop jump tests and the risk of acute noncontact knee or ankle injuries in young team sport athletes.

DESIGN

Prospective cohort study.

METHODS

A 2-dimensional video analysis was used to measure the frontal plane knee projection angle in the single-leg vertical drop jump (VDJ) and the bilateral VDJ in young team sport athletes. Out of the 364 athletes (187 male, 177 female), 189 played basketball and 175 played floorball.

RESULTS

Six male athletes sustained knee injuries and 23 sustained ankle injuries. Frontal plane knee projection angle in the single-leg VDJ or the bilateral VDJ was not associated with ankle injuries among male athletes. No statistical analysis was performed for the knee injuries. Among female athletes, 28 sustained knee and 41 sustained ankle injuries. Frontal plane knee projection angle during the single-leg VDJ or the bilateral VDJ was not a risk factor for knee or ankle injuries.

CONCLUSION

Lower extremity alignment during unilateral and bilateral drop jump tests was not associated with future noncontact knee or ankle injuries among young team sport athletes. The findings should be interpreted cautiously due to the small number of injuries. J Orthop Sports Phys Ther 2020;50(5):267-274. doi:10.2519/jospt.2020.9247.

Landing Stiffness Between Individuals With and Without a History of Low Back Pain

CONTEXT

Reduced spinal stabilization, delayed onset of muscle activation, and increased knee joint stiffness have been reported in individuals with a history of low back pain (LBP). Biomechanical adaptations resulting from LBP may increase the risk for future injury due to suboptimal loading of the lower-extremity or lumbar spine. Assessing landing mechanics in these individuals could help identify which structures might be susceptible to future injury.

OBJECTIVE

To compare vertical and joint stiffness of the lower-extremity and lumbar spine between individuals with and without a previous history of LBP.

DESIGN

Cross-sectional study.

SETTING

Research laboratory.

PARTICIPANTS

There were 45 participants (24 without a previous history of LBP-age 23 [8] y, height 169.0 [8.5] cm, mass 69.8 [13.8] kg; 21 with a previous history of LBP-age 25[9] y, height 170.0 [8.0] cm, mass 70.2 [11.8] kg).

INTERVENTIONS

Single-limb landing trials on the dominant and nondominant limb from a 30-cm box.

MAIN OUTCOME MEASURES

Vertical stiffness and joint stiffness of the ankle, knee, hip, and lumbar spine.

RESULTS

Individuals with a previous history of LBP had lower vertical stiffness (P = .04), but not joint stiffness measures compared with those without a previous history of LBP (P > .05). Overall females had lower vertical (P = .01), ankle (P = .02), and hip stiffness (P = .04) compared with males among all participants. Males with a previous history of LBP had lower vertical stiffness compared with males without a previous history LBP (P = .01). Among all individuals without a previous history of LBP, females had lower vertical (P < .01) and ankle stiffness measures (P = .04) compared with males.

CONCLUSIONS

Landing stiffness may differ among males and females and a previous history of LBP. Comparisons between individuals with and without previous LBP should be considered when assessing landing strategies, and future research should focus on how LBP impacts landing mechanics.

Ankle strength is not strongly associated with postural stability in patients awaiting surgery for chronic lateral ankle instability

PURPOSE

(1) To describe ankle strength and postural stability in patients with chronic lateral ankle instability and (2) to analyse the correlation between deficits in ankle strength and postural stability.

METHODS

Results of preoperative isokinetic and balance tests in 203 patients whose contralateral ankle was normal were retrospectively reviewed. Isokinetic peak torque values of eversion and inversion at 2 angular velocities (30°/s and 120°/s) were measured in the injured and normal ankles. In the balance test, the percent differences of 3 actual scores (overall, anterior-posterior, and medial-lateral) between the injured and normal ankles were calculated. Additional statistical analyses were performed to evaluate weakness of ankle strength, postural stability deficits, and their correlation.

RESULTS

Significant differences in 4 peak torque values and 4 relative peak torque values (peak torque/body weight) were found between the injured and normal ankles. All 8 values were significantly lower in the injured ankles. Weakness was severe during inversion and at 30°/s. In the balance test, 49 subjects (24.1%) had significant deficits in postural stability and 109 (53.7%) had favourable results. No strong association was found between weakness of ankle strength and deficits in postural stability.

CONCLUSIONS

Strength measurement alone is insufficient to evaluate preoperative functional deficits, and other functional tests are required to measure postural stability. The results of this study provide further evidence for a rehabilitation programme consisting of proprioceptive training as well as strengthening. The proprioceptive training must be an integral part of the rehabilitation programme in addition to strengthening exercise.

LEVEL OF EVIDENCE

Case series, Level IV.

Trunk muscle function and pelvic alignment associated with the presence of pain in higher education students: a cross-sectional study

Abstract Introduction: The protective role of muscles in the passive structures of the spine means that their stability and consequent maintenance are associated with pain, especially in the region of the lumbo-pelvic-hip complex. Objective: To determine the prevalence of pain and its association with muscle deficits in higher education students. Method: Descriptive, observational, cross-sectional study that evaluated 120 university students through questionnaires (sample characterization, Nordic musculoskeletal symptoms, pain visual analogue scale and international physical activity). Trunk muscle strength and bridge tests with unilateral knee extension (pelvic alignment) were performed. Results: A high prevalence of pain was found in the lower back (58.41%). There was no association between the presence of pain, muscle strength and pelvic alignment (p> 0.05). There was an association between the trunk extension and pelvic tilt tests (p = 0.009). Conclusion: A high prevalence of low back pain, poor performance in the trunk muscle endurance tests and mild and moderate pelvic misalignment were identified. There was no association between pain, trunk muscle weakness and pelvic misalignment. There was an association between pelvic misalignment and trunk extensor muscle weakness.

THE EFFECT of ONE-ON-ONE INTERVENTION in ATHLETES with MULTIPLE RISK FACTORS for INJURY

Background

Lower extremity injuries in soccer players are extremely common. Implementation of group injury prevention programs has gained popularity due to time and cost-effectiveness. Unfortunately, players with greater number of risk factors are most likely to sustain an injury, yet less likely to benefit from a group injury prevention program. The purpose of this study was to determine if targeting these high risk players with one-on-one treatment would result in a reduction in the number of risk factors they possess. The authors hypothesized that fifty percent or more of subjects receiving one-on-one intervention would have a reduction of ≥1 risk factor(s).

Study Design

Quasi-experimental pretest-posttest design.

Methods

Division I men's and women's soccer players were screened for modifiable risk factors using a battery of tests which assessed mobility, fundamental movement pattern performance, motor control, and pain. Players with ≥ 3 risk factors ("high risk") received one-on-one treatment from a physical therapist via an algorithm twice per week for four weeks. Players with < 3 risk factors ("low risk") did not receive one-on-one intervention.

Results

The proportion of treatment successes in the intervention group was 0.923 (95% CI 0.640-0.998). A significant proportion of high risk subjects (0.846) became low risk at posttest (p = 0.003). A significant between group difference was noted in risk factor change from pretest to posttest (p = 0.002), with the median risk factor change in the intervention group being -3.

Conclusion

Utilizing one-on-one interventions designed to target evidence-based risk factors is an effective strategy to eliminate LE musculoskeletal injury risk factors in high risk individuals.

Levels of Evidence

2b.

A COMPARATIVE STUDY OF CORE MUSCULATURE ENDURANCE AND STRENGTH BETWEEN SOCCER PLAYERS WITH AND WITHOUT LOWER EXTREMITY SPRAIN AND STRAIN INJURY

BACKGROUND

Lower extremity sprain and strain injury constitutes a large percentage of lower extremity injuries experienced by soccer players. Yet, very limited data exists on the association between core strength and endurance and this injury.

PURPOSE

The purpose of this study was to compare core muscle endurance and hip muscle strength between soccer players who experienced non-contact lower extremity sprain and/or strain injury during their season and those who did not. Additionally, the frequency of injury was correlated with core muscle endurance and hip strength, and endurance was used for predicting the risk for injury.

STUDY DESIGN

Prospective cohort.

METHODS

Twenty-one (35.59%) athletes experienced non-contact lower extremity sprain and/or strain injury during the season. Fifty-nine male athletes (mean age 20.92 ± 4.08 years, mass 77.34 ± 12.02 kg and height 1.79 ± 0.06m) were tested. Prior to the start of the season, prone-bridge, side-bridge, trunk flexion and horizontal back extension hold times were recorded for endurance assessment and peak hip abductor and external rotator isokinetic torques for strength assessment.

RESULTS

Prone-bridge and side-bridge hold times were significantly longer in the non-injured players when compared with the times of the injured players (p=0.043 & 0.008 for the prone-bridge and side-bridge, respectively). There were significant negative correlations between the frequency of injury and both prone-bridge (r=-0.324, p=0.007) and side-bridge (r=-0.385, p=0.003) hold times. Logistic regression analysis revealed that side-bridge hold time was a significant predictor of injury (OR=0.956, CI=0.925-0.989).

CONCLUSION

Soccer players with non-contact lower extremity sprain and/or strain have less core endurance than non-injured players. Reduced core endurance is associated with increased incidence of injury. Improving side-bridge hold time, specifically, may reduce the risk for injury.

LEVEL OF EVIDENCE

1b.

Impaired Core Stability as a Risk Factor for the Development of Lower Extremity Overuse Injuries: A Prospective Cohort Study

BACKGROUND

Core stability has been suggested to influence lower extremity functioning and might contribute to the development of lower extremity overuse injuries. However, prospective studies to investigate this relationship are limited.

PURPOSE

To research the role of different components of core stability as risk factors for the development of lower extremity overuse injuries.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 142 first-year physical education students participated in this study. They were tested in 2015 and were prospectively followed for 1.5 years by means of a multilevel injury registration method. Three participants were excluded owing to physical complaints during testing. As such, 139 participants were included in the statistical analysis. At baseline, dynamic postural control, isometric core and hip muscle strength, core muscle endurance, core neuromuscular control and proprioception, and functional movement were measured for all participants. Competing risk regression analyses were performed to identify significant contributors to the development of lower extremity overuse injuries.

RESULTS

During the follow-up period, 34 (24%) of the 139 participants developed a lower extremity overuse injury. Significant predictive effects for an overuse injury were found for an increased side-by-side difference in dynamic postural control ( P = .038), decreased isometric hip extension:flexion strength ratio ( P = .046), and decreased abdominal core muscle endurance ( P = .032).

CONCLUSION

This study identified measures for dynamic postural control, core muscle strength, and core muscle endurance as significant risk factors for the development of overuse injuries after statistical model building. However, core neuromuscular control and proprioception and functional movement might not allow clinicians to identify patients at risk. These accessible, reliable screening tools could be used in clinical practice with regard to screening and injury prevention for overuse injuries. Injury prediction based on this model needs to be done with caution given the low relative predictive accuracy (53%).

Risk Factors for Initial and Subsequent Core or Lower Extremity Sprain or Strain Among Collegiate Football Players

CONTEXT

Exposure to game conditions and previous injury are known to increase the risk of injury, but little available evidence pertains to modifiable factors that may mediate dynamic control of body segments, such as core muscle endurance and neurocognitive capabilities.

OBJECTIVE

To identify potentially modifiable factors associated with the occurrence of a core or lower extremity sprain or strain during participation in football.

DESIGN

Prospective cohort study.

SETTING

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

PATIENTS OR OTHER PARTICIPANTS

All team members who participated for the duration of 1 season or both of 2 consecutive seasons (n = 142).

MAIN OUTCOME MEASURE(S)

Predictors of injury occurrence were derived from analysis of preparticipation data that included the results of front plank hold (FPH) and neurocognitive tests. Receiver operating characteristic analysis was used to establish binary classifications of injury risk. Logistic regression analyses were conducted to build multivariable injury-prediction models for optimal discriminatory power.

RESULTS

Exceptionally good discrimination between injured and noninjured participants was provided by models that included the results of the FPH and ImPACT neurocognitive tests. A high level of exposure to game conditions and injury during the preceding year magnified the effects of other risk factors. A model for identifying players with an elevated risk for injury occurrence during both of 2 consecutive seasons included FPH ≤120 seconds, verbal memory score ≤87, composite reaction time ≥560 milliseconds, and starter status. Having ≥2 of the 4 risk factors demonstrated 44% sensitivity and 91% specificity, with an odds ratio = 8.40.

CONCLUSIONS

Core muscle endurance and neurocognitive processes may both play important roles in generating anticipatory muscle stiffness during participation in collegiate football. These factors may be particularly important for players who sustained an injury during the previous year and those who have a high level of game exposure.

Rehabilitation before regenerative cartilage knee surgery: a new prehabilitation guideline based on the best available evidence

INTRODUCTION

Focal cartilage defects are an increasingly relevant clinical problem especially in athletes. Cartilage regenerative surgery (CRS) including microfracture and autologous chondrocyte implantation (ACI) to treat such isolated cartilage defects in the knee joint has been well established in the last two decades. In contradiction to high-level evidence concerning the surgical technique, cell-related issues, and clinical results, the knowledge about the optimal rehabilitation process is still sparse although the importance of optimizing the rehabilitation process has recently led to new research focus in this field. The preoperative time frame may be used to start rehabilitation which may fasten the postoperative recovery and optimize clinical outcome ("Prehabilitation"-PREHAB). The aim of this article, therefore, was to review the available literature on prehabilitation concepts and to present a prehabilitation guideline for CRS patients based on the best evidence available.

METHODS

A systemic literature research was conducted on rehabilitation for cartilage regenerative surgery as well as prehabilitation in knee joint procedures. From the available literature a prehabilitation concept was generated and tested in 10 ACI patients.

RESULTS

As the literature search found no studies addressing prehabilitation in CRS patients, an evidence-based PREHAB program has been compiled based on the available evidence from (a) studies addressing postoperative rehabilitation in CRS patients and (b) PREHAB studies on other knee procedures including TKA. This presented prehabilitation guideline has been tested in > 50 CRS patients and was found to be feasible as all of the patients showed a good compliance and were able to perform the protocol as suggested.

CONCLUSION

The presented PREHAB regimen may serve clinicians as a guideline for early rehabilitation of their CRS patients. Obviously, further research is mandatory to quantify its clinical effect and to demonstrate its cost-effectiveness and benefits in surgically treated patients.

Reliability of two functional clinical tests to evaluate trunk and lumbopelvic neuromuscular control and proprioception in a healthy population

OBJECTIVES

The need to accurately assess trunk and lumbopelvic proprioception and neuromuscular control is widely accepted. However, based on current literature, there is a lack of reliable clinical tests to evaluate these aspects in clinical practice. The objective of this study is to investigate intra- and inter-tester reliability of the lateral step down test and the lumbopelvic position-reposition test in a healthy population.

METHODS

Protocol and scoring methods were developed for the lateral step down test and lumbopelvic position-reposition test, used to assess trunk and lumbopelvic neuromuscular control and proprioception respectively. Each test was performed once by thirty participants and video analysis for test scoring was performed. Three items on the lateral step down test were scored to evaluate neuromuscular control and, four items on the lumbopelvic position-reposition test were scored to evaluate proprioception. Aggregate scores for each test were calculated based on the separate item scores. Intraclass correlation coefficients and linear weighted kappa coefficients were determined for intra- and inter-tester reliability.

RESULTS

Based on the aggregate score, excellent intra- and inter-tester reliability (ICC (2,1)=0.73-0.88) was found for both tests. Moderate/almost perfect intra-and inter-tester agreement (K=0.62-0.91) was found for the separate items of the lateral step down test and fair/substantial agreement (K=0.25-0.76) for the items of the lumbopelvic position-reposition test.

CONCLUSION

Current testing protocol and scoring method for the lateral step down test is reliable. Adjustments for the scoring method of the lumbopelvic position-reposition test are warranted to improve reliability.

Anticipatory and compensatory postural adjustments in people with low back pain: a systematic review and meta-analysis

BACKGROUND CONTEXT

Despite altered anticipatory (APAs) and compensatory postural adjustments (CPAs) being hypothesized to contribute to the onset and persistence of low back pain (LBP), results from studies comparing people with and without LBP are conflicting.

PURPOSE

This systematic review aimed to determine whether APAs or CPAs are altered in the presence of acute and chronic LBP.

STUDY DESIGN

A systematic review of studies was carried out.

PATIENT SAMPLE

No patient sample was required.

OUTCOME MEASURES

Between group standardized mean differences and 95% confidence intervals for APAs ad CPAs METHODS: A comprehensive search was conducted for articles comparing people with LBP (acute or chronic) to healthy controls for the onset or amplitude of muscle activity, center of pressure (COP), or kinematic responses to expected or unexpected perturbations. Two independent reviewers extracted data and assessed the methodological quality of relevant studies. Differences between people with and without LBP were calculated as standardized mean differences, and included in a meta-analysis if outcomes were homogeneous. Otherwise, a narrative synthesis was conducted.

RESULTS

Twenty-seven studies were included, of which the majority examined muscle onsets in response to expected and unexpected perturbations. Only two studies compared people with and without acute LBP, and results for these studies were conflicting. The results show delayed muscle onsets in response to expected and unexpected perturbations for people with chronic LBP when compared with healthy controls. No conclusive evidence for differences between people with and without chronic LBP for COP or kinematic responses.

CONCLUSIONS

There is currently no convincing evidence of differences between people with and without acute LBP for APAs or CPAs. Conversely, delayed muscle onsets in people with chronic LBP suggest APAs and CPAs are altered in this population. However, the functional relevance of these delayed muscle onsets (eg, COP and kinematics) is unknown.

Methods for Prediction of Core or Lower Extremity Injury Among High School Football Players as a Strategy for Longitudinal Reduction of Injury Risk

Poor neuromechanical control and rapid fatigue of the core muscles are associated with elevated risk for core or lower extremity (CLE) injury. The purpose of this study was to identify preparticipation screening measures associated with both previous and subsequent CLE injuries among high school football players. Self-reported CLE injury history, core muscle endurance, and postural balance were strongly associated with CLE injury. Our findings demonstrated that the same risk categorization cut-points predicted both injury within the previous 12 months and subsequent season injury. Preseason screening results can be used to estimate CLE injury susceptibility among high school football players.

Changes in Muscle Thickness Across Positions on Ultrasound Imaging in Participants With or Without a History of Low Back Pain

CONTEXT

  Injury-prediction models have identified trunk muscle function as an identifiable factor for future injury. A history of low back pain (HxLBP) may also place athletes at increased risk for future low back pain. Reduced muscle thickness of the lumbar multifidus (LM) and transversus abdominis (TrA) has been reported among populations with clinical low back pain via ultrasound imaging in multiple positions. However, the roles of the LM and TrA in a more functional cohort and for injury prediction are still unknown.

OBJECTIVES

  To (1) assess the reliability of LM and TrA ultrasound measures, (2) compare changes in muscle thickness across positions between persons reporting or not reporting HxLBP, and (3) determine the ability to distinguish between groups.

DESIGN

  Cross-sectional study.

SETTING

  Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

  Participants were 34 people who did not report HxLBP (age = 22 ± 7 years, body mass index = 23.7 ± 2.7) and 25 people who reported HxLBP (age = 25 ± 10 years, body mass index = 24.0 ± 3.2).

MAIN OUTCOME MEASURE(S)

  Muscle thickness and changes in muscle thickness of the LM and TrA as shown on ultrasound imaging.

RESULTS

  Intraclass correlation coefficients ranged from 0.641 to 0.943 for all thickness measures and from 0 to 0.693 for all averaged thickness modulations bilaterally. Participants who reported HxLBP had voluntarily reduced TrA thickness modulations compared with those not reporting HxLBP ( P = .03), and the testing position influenced TrA thickness modulations ( P < .01). No differences were observed for LM thickness modulations between groups or positions ( P > .05). A tabletop cutoff value of 1.32 had a sensitivity of 0.640 and a specificity of 0.706, whereas a seated cutoff value of 1.18 had a sensitivity of 0.600 and a specificity of 0.647.

CONCLUSIONS

  In participants reporting HxLBP, TrA thickness modulations were lower and both tabletop and seated thickness modulations were able to distinguish reported HxLBP status. These findings suggest that TrA muscle function may be altered by HxLBP.

Ultrasound Assessment of the Transverse Abdominis During Functional Movement

OBJECTIVES

The traditional activation ratio divides contracted muscle thickness by resting muscle thickness while an abdominal draw-in maneuver is performed during hook lying. Ultrasound imaging during function, such as standing or gait, or peak knee flexion in a single-leg squat allows for further visualization of muscle activity. The goal of this study was to examine activation ratio calculations for transverse abdominis function in supine versus loaded conditions to determine the most informative normalization strategy for muscle activity based on thickness values.

METHODS

Transverse abdominis thickness was measured via ultrasound in 35 healthy participants under 4 different conditions. Comparisons were made between the traditional activation ratio tabletop, standing activation ratio (standing abdominal draw-in maneuver thickness/quiet standing thickness), and functional activation ratio (single-leg squat thickness/quiet standing thickness). Additionally, a cued activation ratio (single-leg squat with cued abdominal draw-in maneuver thickness/single-leg squat thickness) during the single-leg squat was obtained. Activation ratios of greater than 1.0 indicated that participants could activate the muscle during activity, and values were compared by analysis of variance.

RESULTS

The participants included 23 women and 12 men with a mean age ± SD of 21.3 ± 2.7 years, mass of 66.1 ± 14.4 kg, and height of 168.5 ± 10.1 cm. Activation ratios exceeded 1.0 in 94.3% for the traditional activation ratio, 85.7% for the standing activation ratio, 82.9% for the cued activation ratio, and 82.9% for the functional activation ratio. With groups defined as tabletop activated or not, the standing, cued, and functional activation ratios were all significantly different (all P < .05).

CONCLUSIONS

Normalizing muscle thickness to the corresponding functional position quiet value provides a useful functional activation ratio and may help clinicians better understand the transverse abdominis role during complex functional tasks. Assessment techniques using various formulas for activation ratios reveal that the muscle functions differently during weight bearing compared to traditional measures.

Low back pain and disability in individuals with plantar heel pain

BACKGROUND

Lack of response to plantar heel pain (PHP) treatment may be related to unmanaged low back pain (LBP) and low back dysfunction, but a relationship between LBP and PHP has not been established. The purpose of this investigation was to compare the prevalence of LBP among individuals with and without PHP and to assess the association between low back disability and foot/ankle function.

METHODS

A cross-sectional study compared the prevalence and likelihood of LBP in individuals with (n=27) and without (n=27) PHP matched to age, sex, BMI, foot posture, and foot mobility. In individuals with PHP, correlations were examined between foot/ankle function using the foot and ankle ability measure (FAAM), low back disability using the Oswestry low back disability questionnaire (OSW), duration of PHP symptoms, body mass index (BMI), and age.

RESULTS

A greater percentage of individuals with PHP had LBP (74% versus 37% of controls, odds ratio=5.2, P=0.009) and higher levels of low back disability (17% higher OSW score than controls, P<0.001). In individuals with PHP, FAAM scores were correlated with OSW scores (ρ=-0.463, P=0.015), but not with duration of PHP symptoms, BMI, or age (P>0.150).

CONCLUSIONS

Individuals with PHP had a greater prevalence of LBP and higher low back disability that was correlated to reduced foot and ankle function. Treatment to address both local and proximal impairments, including impairments related to LBP, may be warranted to improve the management of PHP.

Evaluating abdominal core muscle fatigue: Assessment of the validity and reliability of the prone bridging test

The aims of this study were to research the amplitude and median frequency characteristics of selected abdominal, back, and hip muscles of healthy subjects during a prone bridging endurance test, based on surface electromyography (sEMG), (a) to determine if the prone bridging test is a valid field test to measure abdominal muscle fatigue, and (b) to evaluate if the current method of administrating the prone bridging test is reliable. Thirty healthy subjects participated in this experiment. The sEMG activity of seven abdominal, back, and hip muscles was bilaterally measured. Normalized median frequencies were computed from the EMG power spectra. The prone bridging tests were repeated on separate days to evaluate inter and intratester reliability. Significant differences in normalized median frequency slope (NMF_slope ) values between several abdominal, back, and hip muscles could be demonstrated. Moderate-to-high correlation coefficients were shown between NMF_slope values and endurance time. Multiple backward linear regression revealed that the test endurance time could only be significantly predicted by the NMF_slope of the rectus abdominis. Statistical analysis showed excellent reliability (ICC=0.87-0.89). The findings of this study support the validity and reliability of the prone bridging test for evaluating abdominal muscle fatigue.

PREDICTION OF FUNCTIONAL MOVEMENT SCREEN™ PERFORMANCE FROM LOWER EXTREMITY RANGE OF MOTION AND CORE TESTS

BACKGROUND

There are varied reports in the literature regarding the association of the Functional Movement Screen™ (FMS™) with injury. The FMS™ has been correlated with hamstring range of motion and plank hold times; however, limited research is available on the predictability of lower extremity range of motion (ROM) and core function on FMS™ performance.

PURPOSE/HYPOTHESES

The purpose of this study was to examine whether active lower extremity ROM measurements and core functional tests predict FMS™ performance. The authors hypothesized that lower extremity ROM and core functional tests would predict FMS™ composite score (CS) and performance on individual FMS™ fundamental movement patterns.

STUDY DESIGN

Descriptive cohort study.

METHODS

Forty recreationally active participants had active lower extremity ROM measured, performed two core functional tests, the single leg wall sit hold (SLWS) and the repetitive single leg squat (RSLS), and performed the FMS™. Independent t tests were used to assess differences between right and left limb ROM measures and outcomes of core functional tests. Linear and ordinal logistic regressions were used to determine the best predictors of FMS™ CS and fundamental movement patterns, respectively.

RESULTS

On the left side, reduced DF and SLWS significantly predicted lower FMS™ CS. On the right side only reduced DF significantly predicted lower FMS™ CS. Ordinal logistic regression models for the fundamental movement patterns demonstrated that reduced DF ROM was significantly associated with lower performance on deep squat. Reduced left knee extension was significantly associated with better performance in left straight leg raise; while reduced right hip flexion was significantly associated with reduced right straight leg raise. Lower SLWS was associated with reduced trunk stability performance.

CONCLUSIONS

FMS™ movement patterns were affected by lower extremity ROM and core function. Researchers should consider lower FMS™ performance as indicative of underlying issues in ROM and core function. Clinicians may consider ROM interventions and core training strategies to improve FMS™ CS.

LEVEL OF EVIDENCE

Level 2B.

PROSPECTIVE FUNCTIONAL PERFORMANCE TESTING AND RELATIONSHIP TO LOWER EXTREMITY INJURY INCIDENCE IN ADOLESCENT SPORTS PARTICIPANTS

BACKGROUND

Due to the high number of adolescent athletes and subsequent lower extremity injuries, improvements of injury prevention strategies with emphasis on clinic-based and practical assessments are warranted.

PURPOSE

The purpose of this study was to prospectively investigate if a battery of functional performance tests (FPT) could be used as a preseason-screening tool to identify adolescent athletes at risk for sports-related acute lower extremity injury via comparison of injured and uninjured subjects.

METHODS

One hundred adolescent volleyball, basketball and soccer athletes (female, n=62; male, n=38; mean age = 14.4 ± 1.6) participated. The FPT assessment included: triple hop for distance, star excursion balance test, double leg lowering maneuver, drop jump video test, and multi-stage fitness test. Composite scores were calculated using a derived equation. Subjects were monitored throughout their designated sport season(s), which consisted of a six-month surveillance period. The schools certified athletic trainer (ATC) recorded all injuries. Subjects were categorized into groups according to sex and injury incidence (acute lower extremity injury vs. uninjured) for analysis.

RESULTS

Mean FPT composite scores were significantly lower for the injured compared to the uninjured groups in both sexes (males: 19.06 ± 3.59 vs. 21.90 ± 2.44; females: 19.48 ± 3.35 vs. 22.10 ± 3.06 injured and uninjured, respectively)(p < .05). The receiver-operator characteristic analysis determined the cut-off score at ≤ 20 for both genders (sensitivity=.71, specificity=.81, for males; sensitivity=.67, specificity=.69, for females)(p<.05) for acute noncontact lower extremity injuries. Significant positive correlations were found between the FPT composite score and the multi-stage fitness test in male subjects (r=.474, p=.003), suggesting a relationship between functional performance, aerobic capacity, and potential injury risk.

CONCLUSION

A comprehensive assessment of functional performance tests may be beneficial to identify high-injury risk adolescents prior to athletic participation.

Hip Strength as an Intrinsic Risk Factor for Lateral Ankle Sprains in Youth Soccer Players: A 3-Season Prospective Study

BACKGROUND

Numerous epidemiological studies have emphasized the burden of lateral ankle sprains in youth soccer players. However, no prospective study has identified intrinsic physical and modifiable risk factors for these injuries in this particular population. Although injury prevention programs in soccer incorporate proximal hip and core stability exercises, it is striking that the relationship between impaired proximal hip function and ankle sprains has not yet been prospectively investigated in youth soccer players.

HYPOTHESIS

This prospective study aimed to examine whether hip muscle strength is a risk factor for sustaining a lateral ankle sprain in youth soccer players. We hypothesized that decreased hip muscle strength would predispose youth soccer players to an increased risk of lateral ankle sprains.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

This study included a total of 133 male youth soccer players (age divisions U11-U17) for analysis. At the beginning of the season, anthropometric characteristics were collected and hip muscle strength was assessed using a handheld dynamometer. Injury registration was performed by the team medical staff during 3 consecutive seasons. A principal-component, multivariate Cox regression analysis was performed to identify potential risk factors for sustaining a lateral ankle sprain.

RESULTS

Twelve participants (18% of all reported injuries) sustained a lateral ankle sprain (0.36 per 1000 athletic-exposure hours). After adjustment for body size dependencies and other hip muscle forces, an increase in hip muscle extension force was associated with a significant decrease in the hazard of the injury (hazard ratio, 0.3; 95% confidence interval, 0.1-0.9; P = .028). No other study variable could be identified as a risk factor for lateral ankle sprains.

CONCLUSION

Reduced hip extension muscle strength is an independent risk factor for lateral ankle sprains in male youth soccer players. Other hip muscle strength outcomes were not identified as risk factors. Replication in larger samples with more injured cases is warranted to further ascertain the importance of this risk factor.

A Sport Fitness Index for Assessment of Sport-Related Injury Risk

OBJECTIVE

To develop and validate a concise survey that will identify athletes who possess elevated injury risk.

DESIGN

Cohort study.

SETTING

National Collegiate Athletic Association Division I athletic program.

PARTICIPANTS

Cohorts of 188 and 146 college athletes who participated during successive academic years.

ASSESSMENT OF RISK FACTORS

The first cohort provided responses to 4 joint-specific outcome surveys that were related to subsequent time-loss injury occurrence. Receiver operating characteristic analysis identified survey items that provided best discrimination, which were combined with a negative life event stress item to create a new 10-item survey. The second cohort provided responses to the new survey, which were converted to a 0 to 100 score.

MAIN OUTCOME MEASURES

Construct validity was assessed through documentation of time-loss injuries sustained during the preceding 12 months and predictive validity was assessed through prospective documentation of sport-related sprains and strains. Cronbach alpha was calculated to assess internal consistency.

RESULTS

Each of the outcome survey items used to develop the new survey demonstrated much greater specificity than sensitivity. Both the retrospective and prospective receiver operating characteristic (ROC) analyses identified scores of 96 and 88 as cut-points that provided good discrimination between injured and noninjured cases. The area under the curve was 0.69 (P < 0.001) for the retrospective analysis and 0.62 (P = 0.016) for the prospective analysis. Cronbach alpha was 0.89 (90% CI, 0.86-0.91).

CONCLUSIONS

Self-reported effects of previous injury may be one method to efficiently identify athletes who possess elevated injury risk, and subsequently deliver preventive interventions, thereby providing an alternative method to time-intensive functional testing.

Predicting Musculoskeletal Injury in National Collegiate Athletic Association Division II Athletes From Asymmetries and Individual-Test Versus Composite Functional Movement Screen Scores

CONTEXT

Functional Movement Screen (FMS) scores of ≤14 have been used to predict injury in athletic populations. Movement asymmetries and poor-quality movement patterns in other functional tests have been shown to predict musculoskeletal injury (MSI). Therefore, movement asymmetry or poor-quality movement patterns on the FMS may have more utility in predicting MSI than the composite score.

OBJECTIVE

To determine if an asymmetry or score of 1 on an individual FMS test would predict MSI in collegiate athletes.

DESIGN

Cohort study.

SETTING

National Collegiate Athletic Association Division II university athletic program.

PATIENTS OR OTHER PARTICIPANTS

A total of 84 Division II rowers, volleyball players, and soccer players (men: n = 20, age = 20.4 ± 1.3 years, height = 1.77 ± 0.04 m, mass = 73.5 ± 4.8 kg; women: n = 64, age = 19.1 ± 1.2 years, height = 1.69 ± 0.09 m, mass = 64.8 ± 9.4 kg).

MAIN OUTCOME MEASURE(S)

The FMS was administered during preseason preparticipation examinations. Injury-incidence data were tracked for an academic year by each team's certified athletic trainer via computer software. An MSI was defined as physical damage to the body secondary to athletic activity or an event for which the athlete sought medical care, and resulted in modified training or required protective splitting or taping. Composite FMS scores were categorized as low (≤14) or high (>14). Pearson χ(2) analyses were used to determine if MSI could be predicted by the composite FMS score or an asymmetry or score of 1 on an individual FMS test (P < .05).

RESULTS

Athletes with FMS scores of ≤14 were not more likely to sustain an injury than those with higher scores (relative risk = 0.68, 95% confidence interval = 0.39, 1.19; P = .15). However, athletes with an asymmetry or individual score of 1 were 2.73 times more likely to sustain an injury than those without (relative risk = 2.73, 95% confidence interval = 1.36, 5.4; P = .001).

CONCLUSIONS

Asymmetry or a low FMS individual test score was a better predictor of MSI than the composite FMS score.

Reliability of Ultrasound Imaging Measures of Transverse Abdominis and Lumbar Multifidus in Various Positions

OBJECTIVE

To determine the reliability of measurement of muscle activation via ultrasound imaging measures of the transverse abdominis (TrA) and lumbar multifidus (LM) in tabletop, seated, standing, and walking conditions.

DESIGN

Descriptive laboratory study.

SETTING

University research laboratory.

PARTICIPANTS

Sixteen healthy participants (age, 20.4 ± 1.8 years; height, 167.7 ± 9.0 cm; mass, 65.1 ± 10.8 kg).

INTERVENTIONS

None.

MAIN OUTCOME MEASUREMENTS

The activation ratio (AR) of TrA and LM and preferential activation ratio of TrA in tabletop, seated, standing, and walking positions were assessed by the same examiner during 2 ultrasound imaging sessions 24-72 hours apart. Statistical analysis included determination of intraclass correlation coefficients (ICCs) using analysis of variance for each muscle and position between sessions.

RESULTS

Excellent reliability was found in TrA AR between sessions for healthy participants in the tabletop position (ICC3,k = 0.903), and acceptable to excellent reliability was found in seated (ICC3,k = 0.613), standing (ICC3,k = 0.553), and walking (ICC3,k = 0.737) positions. LM AR was fair in the tabletop position for these participants (ICC3,k = 0.264). The preferential activation ratio for healthy participants was substantially reliable in tabletop and seated positions (ICC3,k = 0.668, 0.684) and showed fair reliability for walking (ICC3,k = 0.455).

CONCLUSIONS

Ultrasound imaging is a reliable method of measuring muscle thickness across multiple positions in healthy persons. This measure may be used to compare abdominal muscle thickness across populations or after interventions. LM AR was only found to be reliable in the tabletop position.

Relation between performance in side bridge and injuries in amateur soccer

AbstractIntroduction Central instability is associated with insufficient endurance and strength of the stabilizer muscles, and it can lead to muscle imbalance and injuries.Objective Relate side bridge performance with the presence of injuries in amateur soccer athletes.Materials and methods A cross-sectional study with a sample of 188 male athletes, aged between 11 and 17 years. To identify the injuries, a questionnaire developed by researchers was applied and the players’ clinical records were reviewed. The time of the side bridge test was used to identify muscle imbalance. For statistical analysis, the following tests were used: chi-square test; Pearson’s chi-square test; Fisher’s exact test; Yates’s correction for continuity; two-way ANOVA; one-way ANOVA; and t-test. The significance level (α) of 5% was adopted.Results Injuries were reported by 59.6% of the athletes: sprain (31.3%); muscle strain (28.6%) and fracture; luxation and subluxation (19.6%) were the most frequently reported injuries. Athletes that reported any injury corresponded to 73.2% of the sample. The presence of injuries was not associated with muscle imbalance (p = 0.565), as it prevailed in athletes with both balance (64%) and imbalance (58%). Injury type and prevalence were not significant when compared with the presence of imbalance (p > 0.05).Final considerations No significant relation between muscle imbalance and injury was observed in the studied sample.