REDUCED HIP STRENGTH IS ASSOCIATED WITH INCREASED HIP MOTION DURING RUNNING IN YOUNG ADULT AND ADOLESCENT MALE LONG‐DISTANCE RUNNERS

Study Design:

Controlled laboratory study.

Background and Purpose:

Anterior knee pain is one of the most common running symptoms reported in the literature. While the exact etiology is unknown, a lack of hip strength is suggested to contribute to abnormal running mechanics. The purpose of this research study was to evaluate the association between isokinetic hip strength and 3‐D running kinematics.

Methods:

33 male high school and collegiate cross country runners participated in this study. Peak isokinetic hip abductor and hip extensor strength were assessed. Each subject also completed a treadmill running protocol at a self‐selected speed (mean = 3.8 m/s). 3‐D kinematic data were collected at 240 Hz using a 10‐camera motion capture system. Pearson correlation coefficients were used to determine the relationship between hip strength and hip range of motion (ROM) during the stance phase of running (p<0.05).

Results:

Peak isokinetic hip extensor torque was inversely correlated with transverse plane hip ROM (r = −.387, p = .026) but was not significantly related to sagittal plane hip ROM or frontal plane hip ROM. Peak isokinetic hip abductor torque was inversely correlated with frontal plane hip ROM (r=−.462, p=.008) but was not significantly related to either sagittal plane hip ROM or transverse plane hip ROM. Peak isokinetic hip extensor torque and peak isokinetic hip abductor torque were not significantly related to knee kinematics in any plane.

Conclusions:

Peak isokinetic hip extensor torque and peak isokinetic hip abductor torque are associated with transverse plane and frontal plane hip kinematics, but not knee kinematics.

Levels of Evidence:

Level 3b     

RELIABILITY OF VIDEO‐BASED QUANTIFICATION OF THE KNEE‐ AND HIP ANGLE AT FOOT STRIKE DURING RUNNING

Introduction:

In clinical practice, joint kinematics during running are primarily quantified by two‐dimensional (2D) video recordings and motion‐analysis software. The applicability of this approach depends on the clinicians’ ability to quantify kinematics in a reliable manner. The reliability of quantifying knee‐ and hip angles at foot strike is uninvestigated.

Objective:

To investigate the intra‐ and inter‐rater reliability within and between days of clinicians’ ability to quantify the knee‐ and hip angles at foot strike during running.

Methods:

Eighteen recreational runners were recorded twice using a clinical 2D video setup during treadmill running. Two blinded raters quantified joint angles on each video twice with freeware motion analysis software (Kinovea 0.8.15)

Results:

The range from the lower prediction limit to the upper prediction limit of the 95% prediction interval varied three to eight degrees (within day) and nine to 14 degrees (between day) for the knee angles. Similarly, the hip angles varied three to seven degrees (within day) and nine to 11 degrees (between day).

Conclusion:

The intra‐ and inter rater reliability of within and between day quantifications of the knee‐ and hip angle based on a clinical 2D video setup is sufficient to encourage clinicians to keep using 2D motion analysis techniques in clinical practice to quantify the knee‐ and hip angles in healthy runners. However, the interpretation should include critical evaluation of the physical set‐up of the 2D motion analysis system prior to the recordings and conclusions should take measurement variations (3‐8 degrees and 9‐14 degrees for within and between day, respectively) into account.

Level of evidence:

3     

REHABILITATION AFTER HIP ARTHROSCOPY AND LABRAL REPAIR IN A HIGH SCHOOL FOOTBALL ATHLETE

Study Design:

Case Report

Background:

Femoral acetabular impingement (FAI) has been implicated in the etiology of acetabular labral tears. The rehabilitation of younger athletes following arthroscopic surgery for FAI and labral tears is often complex and multifactorial. A paucity of evidence exists to describe the rehabilitation of younger athletes who have undergone arthroscopic hip surgery.

Case Presentation:

This case report describes a four-phase rehabilitation program for a high school football player who underwent hip arthroscopy with a labral repair and chondroplasty.

Outcomes:

The player returned to training for football 16 weeks later and at the 4 month follow-up was pain free with no signs of FAI.

Discussion:

There is little evidence regarding the rehabilitation of younger athletes who undergo arthroscopic hip surgery. This case study described a four phase rehabilitation program for a high school football player who underwent hip arthroscopy and labral repair. The patient achieved positive outcomes with a full return to athletic activity and football. The overall success of these patients depends on the appropriate surgical procedure and rehabilitation program.

Key Words:

Femoral acetabular impingement (FAI), hip, hip impingement

Level of evidence:

4-Case report     

OFF‐SEASON TRAINING HABITS AND PRESEASON FUNCTIONAL TEST MEASURES OF DIVISION III COLLEGIATE ATHLETES: A DESCRIPTIVE REPORT

Purpose/Background:

Division III (D III) collegiate coaches are challenged to assess athletic readiness and condition their athletes during the preseason. However, there are few reports on off‐season training habits and normative data of functional assessment tests among D III athletes. The purpose of this study was to examine off‐season training habits of D III athletes and their relationships to the standing long jump (SLJ) and single‐leg hop (SLH) tests.

Methods:

One‐hundred and ninety‐three athletes (110 females, age 19.1 ± 1.1 y; 83 males, age 19.5 ± 1.3 y) were tested prior to the start of their sports seasons. Athletes reported their off‐season training habits (weightlifting, cardiovascular exercise, plyometric exercise, and scrimmage) during the six weeks prior to the preseason. Athletes also performed three maximal effort SLJs and three SLHs.

Results:

Male athletes reported training more hours per exercise category than their female counterparts. Mean SLJ distances (normalized to height) were 0.79 ± 0.10 for females and 0.94 ± 0.12 for males. Mean SLH distances for female athletes'' right and left limbs were 0.66 (± 0.10) and 0.65 (± 0.10), respectively. Mean SLH distances for male athletes'' right and left limbs were 0.75 (± 0.13) and 0.75 (± 0.12), respectively. Several significant differences between off‐season training habits and functional test measures were found for both sexes: males [SLJ and weightlifting (p = 0.04); SLH and weightlifting (p = 0.04), plyometrics (p = 0.05)]; females [SLJ and plyometrics (p = 0.04); SLH and scrimmage (p = 0.02)].

Conclusion:

This study provides normative data for off‐season training habits and preseason functional test measures in a D III athlete population. Greater SLJ and SLH measures were associated with increased time during off‐season training.

Clinical Relevance:

The findings between functional tests and off‐season training activities may be useful for sports medicine professionals and strength coaches when designing their preseason training programs.

Level of Evidence:

4     

REGIONAL INTERDEPENDENCE OF THE HIP AND LUMBO‐PELVIC REGION IN DIVISON II COLLEGIATE LEVEL BASEBALL PITCHERS: A PRELIMINARY STUDY

Background

Pitchers may be at greater risk of injury in comparison to other overhead throwing athletes due to the repetition of the pitching motion. It has been reported that approximately 30% of all baseball injuries occur in the lower body. This may be related to limited hip mobility, which can compromise pitching biomechanics while placing excessive stress on the trunk and upper quarter. Hip motion and strength measurements have been reported in professional baseball pitchers but have not been reported in collegiate pitchers.

Purpose

The purpose of this study was to report preliminary findings for passive hip motion and isometric hip muscle strength in collegiate pitchers and compare them to previously published values for professional level pitchers.

Study Design

Cross sectional study

Methods

Twenty‐nine collegiate baseball pitchers (age = 20.0 + 1.4 years, height = 1.88 + 0.06 m; weight = 89.3 + 10.7 kg; body mass index = 25.3 + 2.5 kg/m2) were recruited. Subjects were assessed for hip internal rotation (IR) and external rotation (ER) passive motion, hip anteversion or retroversion, gluteus maximus, gluteus medius, hip internal rotator, hip external rotator strength, and lumbo‐pelvic control with the prone active hip rotation test as described by Sahrmann. Statistical analysis included calculation of subject demographics (means and SD) and use of a two‐tailed t‐test (p >0.05).

Results

Fifty‐two percent of the right‐handed and 50% of the left‐handed pitchers demonstrated poor lumbo‐pelvic motor control with an inability to stabilize during active hip IR and ER even though isolated strength deficits were not detected at a significant level. There were no significant differences in hip passive motion or gluteus medius strength between right and left‐handed pitchers. Differences did exist between collegiate data and previously published values for professional pitchers for IR motion measured in prone and gluteus maximus strength. Hip retroversion was present in 55% of the pitchers primarily in both limbs with four of the pitchers presenting with retroversion singularly in either the stride or trail limb where the ER rotation motion was greater than the IR.

Conclusion

Assessing mobility and muscle strength of the lower quarter in isolation can be misleading and may not be adequate to ensure the potential for optimal pitching performance. These findings suggest that lumbo‐pelvic control in relation to the lower extremities should be assessed as one functional unit. This is the first study to explore hip motion, strength, and lumbo‐pelvic control during active hip rotation in collegiate baseball pitchers.

Evidence Level

2     

NORMATIVE DATA FOR HOP TESTS IN HIGH SCHOOL AND COLLEGIATE BASKETBALL AND SOCCER PLAYERS

Purpose/Background:

Objective, reliable, and valid functional tests may assist with the decision‐making process for rehabilitation as well as assist in pre‐participation screening for targeted interventions to prevent noncontact lower extremity injuries. The purpose of this study was to determine normative values in high school and college basketball and soccer players for four hop tests: the single hop for distance, the triple hop for distance, the crossover hop for distance, and the 6‐m timed hop.

Methods:

A sample of convenience of 372 (185 females, 187 males) healthy high school and collegiate student‐athletes were included in the study (mean age 17.37 years, range 14‐24): 200 were soccer players and 172 were basketball players. Limb dominance was determined based on which extremity participants would choose to kick a ball for distance. A coin flip was used to determine which limb was tested first. Hop test order was randomized using a Latin square design. Participants performed one practice hop and three measured hops for each hop test on each limb. The average hop score for each limb was used for calculations.

Results:

Significant differences in test performance were found between sexes and levels of competition, p < 0.0005, with males performing better than females and collegiate athletes performing better than high school athletes for all hop tests. There were no clinically relevant differences between dominant sports. There were also no clinically relevant differences between dominant and non‐dominant limbs. Normative values for each hop test were proposed, based on sex and level of competition.

Conclusions:

These findings indicate that separate hop test standards should be used based on participant sex and level of competition. While some statistically significant differences were found between limbs, these differences did not appear to be functionally relevant. Further studies are needed to determine if sport‐specific normative hop test values should be utilized and to examine normal limb symmetry indices in specific populations.

Levels of Evidence:

2A     

EFFECTS OF A MOVEMENT TRAINING PROGRAM ON HIP AND KNEE JOINT FRONTAL PLANE RUNNING MECHANICS

Background/Purpose:

Frontal plane running mechanics may contribute to the etiology or exacerbation of common running related injuries. Hip strengthening alone may not change frontal plane hip and knee joint running mechanics. The purpose of the current study was to evaluate whether a training program including visual, verbal, and tactile feedback affects hip and knee joint frontal plane running mechanics among females with evidence of altered weight bearing kinematics.

Methods:

The knee frontal plane projection angle of 69 apparently healthy females was determined during a single leg squat. The twenty females from this larger sample who exhibited the most acute frontal plane projection angle (medial knee position) during this activity were chosen to participate in this study (age = 20 ± 1.6 years, height = 167.9 ± 6.0 cm, mass = 63.2 ± 8.3 kg, Tegner Activity Rating mode = 7.0). Participants engaged in a 4‐week movement training program using guided practice during weight bearing exercises with visual, verbal, and tactile feedback regarding lower extremity alignment. Paired t‐tests were used to compare frontal plane knee and hip joint angles and moments before and after the training program.

Results:

After training, internal hip and knee abduction moments during running decreased by 23% (P=0.007) and 29% (P=0.033) respectively. Knee adduction and abduction excursion decreased by 2.1° (P = 0.050) and 2.7° (P=0.008) respectively, suggesting that less frontal plane movement of the knee occurred during running after training. Peak knee abduction angle decreased 1.8° after training (P=0.051) although this was not statistically significant. Contralateral peak pelvic drop, pelvic drop excursion, peak hip adduction angle, hip adduction excursion, and peak knee adduction angle were unchanged following training.

Conclusions:

A four week movement training program may reduce frontal plane hip and knee joint mechanics thought to contribute to the etiology and exacerbation of some running related injuries.

Level of Evidence:

Level 4     

ASSOCIATIONS BETWEEN THE FEMALE ATHLETE TRIAD AND INJURY AMONG HIGH SCHOOL RUNNERS

Purpose/Background:

During the 2013‐14 school year, over 763,000 female athletes participated in interscholastic running sports in the United States. Recent studies have indicated associations between the female athlete triad (Triad) and stress fracture or other musculoskeletal injuries in elite or collegiate female running populations. Little is known about these relationships in an adolescent interscholastic running population. The purpose of this study was to determine the associations between Triad and risk of lower extremity musculoskeletal injury among adolescent runners.

Methods:

Eighty‐nine female athletes competing in interscholastic cross‐country and track in southern California were followed, prospectively. The runners were monitored throughout their respective sport season for lower extremity musculoskeletal injuries. Data collected included daily injury reports, Eating Disorder Examination Questionnaire (EDE‐Q) that assessed disordered eating attitudes/behaviors, a questionnaire on menstrual history and demographic characteristics, a dual‐energy x‐ray absorptiometry scan that measured whole‐body bone mineral density (BMD) and body composition (lean tissue and fat mass), and anthropometric measurements.

Results:

Thirty‐eight runners (42.7%) incurred at least one lower extremity musculoskeletal injury. In the BMD Z‐score ≤ ‐1 standard deviation (SD) adjusted model, low BMD relative to age (BMD Z‐score of ≤ ‐1SD) was significantly associated (Odds Ratio [OR]=4.6, 95% confidence interval [CI]: 1.5‐13.3) with an increased occurrence of musculoskeletal injury during the interscholastic sport season. In the BMD Z‐score ≤ ‐2 SDs adjusted model, a history of oligo/amenorrhea was significantly associated (OR=4.1, 95% CI: 1.2‐13.5) with increased musculoskeletal injury occurrence.

Conclusion:

Oligo/amenorrhea and low BMD were associated with musculoskeletal injuries among the female interscholastic cross‐country and track runners.

Clinical Relevance:

Regular, close monitoring of adolescent female runners during seasonal and off‐season training may be warranted, so that potential problems can be recognized and addressed promptly in order to minimize the risk of running injury.

Level Of Evidence:

2     

CHANGES IN HIP RANGE OF MOTION AND STRENGTH IN COLLEGIATE BASEBALL PITCHERS OVER THE COURSE OF A COMPETITIVE SEASON: A PILOT STUDY

Background

Adaptations in hip range of motion (ROM) and strength have been shown to influence performance and injury risk in overhead athletes. These adaptations in hip ROM and strength have not been examined longitudinally, and little is known regarding whether these changes are a result of pitching workload.

Hypothesis/Purpose

The authors hypothesized that hip rotation ROM and strength would change over the course of a season, and would be associated with pitching workload (number of pitches over the course of a season). The purpose of this exploratory, pilot study was twofold: 1) to examine changes in hip external rotation (ER) ROM, internal rotation (IR) ROM, isometric hip abduction and hip extension strength in pitchers occurring over the course of a competitive season, and 2) to determine the association between changes in hip ROM, strength, and pitching volume.

Study Design

Cohort (longitudinal) study

Methods

Bilateral hip rotation ROM and hip isometric strength was tested pre‐ and post‐season in fourteen collegiate baseball pitchers. Pearson correlations were calculated to determine the association between changes in hip ROM, strength, and pitching workload.

Results

Trail and lead hip ER, trail and lead hip total rotational ROM, and trail and lead hip abduction strength in all pitchers decreased from preseason to postseason (p < 0.01). However, these changes were not significantly associated with pitching workload (p > 0.05).

Conclusion

This study demonstrates that changes occur in hip ROM and strength in collegiate pitchers over the course of a season. These changes were not associated with pitching workload

Level of Evidence

3     

RELATIONSHIP BETWEEN HIP STRENGTH AND TRUNK,HIP, AND KNEE KINEMATICS DURING A JUMP‐LANDING TASK IN INDIVIDUALS WITH PATELLOFEMORAL PAIN

Background/Purpose:

Decreased strength of the hip musculature and altered mechanics of the lower extremity have been identified in individuals with patellofemoral pain (PFP). The aim of this study was to determine if a relationship exists between hip muscle strength and transverse and frontal plane motion at the hip and knee, and ipsilateral trunk flexion during a jump‐landing task in individuals with PFP.

Methods:

Fifteen individuals (10 females, 5 males) with PFP participated in this investigation. A three‐dimensional motion analysis system was utilized to assess trunk, hip, and knee kinematics during a jump‐landing task. An isokinetic dynamometer was utilized to assess concentric and eccentric strength of the hip musculature. Simple correlation analyses were performed to determine the relationships between hip muscle strength and peak frontal and transverse plane hip and knee kinematics and ipsilateral trunk flexion.

Results:

Decreased eccentric strength of the hip external rotators and abductors was significantly correlated to increased frontal plane motion at the hip and trunk, respectively (P<0.05).

Conclusions:

Based on these findings, eccentric strengthening exercises for the hip musculature may be an important component for clinicians to include when rehabilitating individuals with PFP who display increased frontal plane motion at the hip and trunk.

Level of Evidence:

2b