Preliminary Evaluation of a Questionnaire to Measure Program-Level Sense of Belonging Among Student Physical Therapists.

INTRODUCTION: A greater sense of belonging has been found to correspond with better academic performance/motivation, retention, and general mental well-being among college students. As a result, it is important to be able to meaningfully assess student physical therapists' sense of belonging. REVIEW OF LITERATURE: While there are questionnaires available to assess sense of belonging at the university level, it is also important to be able to assess students' sense of belonging in a narrower context, such as within their program of study. The purpose of this study was to develop and evaluate a program-specific tool, referred to as the Program Sense of Belonging (ProSB) questionnaire, that could be used to assess sense of belonging among student physical therapists. As part of this study, we examined the internal structure of the ProSB questionnaire items and assessed internal consistency. SUBJECTS: One hundred twenty-four student physical therapists from 2 different physical therapist education programs completed the ProSB questionnaire. METHODS: We conducted an exploratory factor analysis to examine the internal structure of the ProSB questionnaire and examined Cronbach's alpha to assess the internal consistency of the items associated with each retained factor. RESULTS: For the final 10-item version of the ProSB questionnaire, 2 factors were retained, which explained 57.5% of the variance (factor 1 = 30.9%, factor 2 = 26.6%). The 5 items that loaded on factor 1 were related to "social acceptance," while the 5 items that loaded on factor 2 were related to "valued competence." Both subscales exhibited acceptable levels of internal consistency (Cronbach's alpha ≥0.84). DISCUSSION: The ProSB questionnaire appears to capture different dimensions of student physical therapists' sense of belonging (social acceptance, valued competence) at the program level. CONCLUSION: Based on our preliminary findings, the ProSB questionnaire appears to be a valid tool for assessing program-level sense of belonging among student physical therapists.

The Modified Reactive Strength Index Is a Valid Measure of Lower-Body Explosiveness in Male and Female High School Athletes.

ABSTRACT: Witte, BC, Schouten, TC, Westphal, JA, VanZile, AW, Jones, DD, Widenhoefer, TL, Dobbs, WC, Jagim, AR, Luedke, JA, and Almonroeder, TG. The modified reactive strength index is a valid measure of lower-body explosiveness in male and female high school athletes. J Strength Cond Res XX(X): 000-000, 2024-The modified reactive strength index (mRSI) is a commonly used metric to quantify lower-body explosiveness during countermovement jump (CMJ) performance. However, few studies have attempted to examine its validity as a measure of explosiveness, particularly among high school athletes. The purpose of this study was to examine the validity of the mRSI as a measure of lower-body explosiveness among a relatively large sample of male and female high school athletes from various sports. As part of this study, male (n = 132) and female (n = 43) high school athletes performed CMJs, while ground reaction forces were recorded using a force platform. The vertical ground reaction force data collected during the CMJs were used to derive the following variables: peak force (PF), peak power, time to PF, time to take-off, peak rate of force development, and the mRSI. Principal component analysis was applied and reduced these variables into 2 components related to "force" and "speed." The mRSI loaded on both the force (loading = 0.82) and speed (loading = -0.46) components, indicating that it incorporates elements of both force and speed, although it loaded more strongly on the force component than the speed component. The observed pattern of cross-loading suggests that the mRSI is generally a valid measure of lower-body explosiveness for male and female high school athletes.

The Effects of Protein and Carbohydrate Supplementation, with and without Creatine, on Occupational Performance in Firefighters.

BACKGROUND: The purpose of this study was to assess the effects of protein and carbohydrate supplementation, with and without creatine, on occupational performance in firefighters. METHODS: Using a randomized, double-blind approach, thirty male firefighters (age: 34.4 ± 8.4 yrs., height: 1.82 ± 0.07 m; weight: 88.6 ± 12.5 kg; BF%: 17.2 ± 5.8%) were randomized to receive either (A.) 25 g of whey protein isolate + 25 g of carbohydrate powder (ProCarb group); or (B.) ProCarb + 5 g of creatine (Creatine group) in a double-blind fashion over a period of 21-26 days (depending on shift rotations) to evaluate the impact of supplementation on occupation-specific performance. At baseline and following supplementation, firefighters completed a battery of tests. These tests included an aerobic speed test on an air-braked cycle ergometer followed by the hose carry, body drag, stair climb, and Keiser sled hammer for time. RESULTS: No significant differences in measures of performance were observed at baseline (p > 0.05). There was a significant main effect for time observed for rescue, stair climb, total time to completion, and time trial performance (p < 0.05). There was a significant group × time (p < 0.05) interaction for rescue and forcible entry. Independent sample t-tests indicated that the Creatine group experienced a greater reduction (from baseline) in completion time for the rescue (1.78 ± 0.57 s, 95% CI: 0.61, 2.95 s, p = 0.004) and forcible entry (2.66 ± 0.97 s, 95% CI: 0.68, 4.65 s, p = 0.01) tests compared to the ProCarb group. No significant group × time interactions were observed for the hose line advance, stair climb, total time to completion, and time trial performance (p > 0.05). CONCLUSIONS: The addition of supplemental creatine to a protein and carbohydrate supplement to the diet of career firefighters throughout a three week period improves occupational performance in firefighters in specific areas of high-intensity, repetitive actions.

Spatial Abilities and Performance in Anatomy for Occupational Therapy and Physical Therapy Doctoral Students.

Spatial ability is the capacity to comprehend three-dimensional structures and positional relationships and to mentally manipulate these structures and relationships to predict the outcome correctly. Spatial ability, which requires extensive knowledge of three-dimensional relationships, contributes to success in endeavors such as studying human anatomy, a foundational component of rehabilitation science curricula. This investigation explored relationships between anatomy course grades, learning preferences, and spatial abilities of graduate healthcare students from two fields of rehabilitation science. We administered the Mental Rotation Test to 95 Doctor of Physical Therapy students and 66 Occupational Therapy students at the start of the anatomy course in the first semester of their professional programs. The spatial abilities of doctoral students in physical therapy and occupational therapy programs reflect consistently reported trends for gender and anatomy performance. Physical therapy students demonstrated higher spatial ability scores than occupational therapy students, which could result from differences in life experience or academic preparation. Awareness of students' spatial abilities, the factors that influence them, and their relationships to student success have important implications for teaching, learning, advising, and retention.

Inter-limb kinetic asymmetries during sit-to-stand performance persist following unilateral total knee arthroplasty: A systematic review and meta-analysis.

BACKGROUND: Kinetic asymmetries during sit-to-stand have been consistently observed early after total knee arthroplasty; however, the longer-term outcomes are less clear. The purpose of this systematic review and meta-analysis was to analyze the results of studies examining inter-limb kinetic symmetry during sit-to-stand performance among individuals who were at least one-year post unilateral total knee arthroplasty. METHODS: PubMed, SPORTDiscus, CINAHL, and Health Source databases were searched. Studies were included if they were published in a peer-reviewed journal, included subjects who had undergone unilateral total knee arthroplasty at least one-year prior, and examined vertical ground reaction forces and/or knee extension moments for the involved and uninvolved limbs during sit-to-stand performance. Data were transformed into a limb symmetry index, which expressed the ratio of the peak forces/moments for the involved limb, relative to the uninvolved limb (1.0 reflects perfect symmetry). These ratios were meta-analyzed using the ratio of means method. FINDINGS: Seven studies were deemed eligible for inclusion. Ground reaction force data was pooled from seven studies and knee extension moment data was pooled from two studies. For the peak vertical ground reaction forces, the pooled limb symmetry index was 0.96 (CI95% = [0.93, 0.99]). For the peak knee extension moments, the pooled limb symmetry index was 0.91 (CI95% = [0.84, 0.98]). In both cases this reflects greater limb/knee loading for the uninvolved limb, relative to the involved limb. INTERPRETATION: Asymmetries in limb/knee loading persist beyond the one-year post-operative period following total knee arthroplasty, potentially contributing to degenerative changes for the uninvolved limb.

Athletes with a History of ACL Reconstruction Exhibit Greater Inter-Limb Asymmetry in Impact Forces During the First Landing of a Drop Vertical Jump Compared to the Second Landing.

The primary objective of this study was to examine the degree of inter-limb asymmetry in impact force magnitudes and rates during the first and second landings of a drop vertical jump in adolescent athletes with a history of anterior cruciate ligament (ACL) reconstruction. We also compared the degree of asymmetry exhibited by the athletes who had undergone ACL reconstruction to a group of uninjured athletes. This study included 14 athletes who had undergone ACL reconstruction and 28 uninjured athletes, matched for age, sex, and sport. All athletes completed a double-leg drop vertical jump task. Peak vertical ground reaction forces (vGRFs) and loading rates were examined for both limbs during the first and second landings of the drop vertical jump. For the athletes who had undergone ACL reconstruction, peak vGRFs were 11.9% greater for the uninvolved limb vs. the involved limb during the first landing; however, peak vGRFs were only 2.4% greater for the uninvolved limb (vs. the involved limb) during the second landing. The athletes who had undergone ACL reconstruction exhibited greater asymmetry in peak vGRFs for the first landing compared to the uninjured athletes; however, there was no difference between the groups (ACL reconstruction, uninjured) for the second landing.

Comparison of Impact Accelerations During Performance of Common Ballet Maneuvers: A Pilot Study.

INTRODUCTION: Ballet landings produce accelerations that are transmitted proximally up the kinetic chain. If overly excessive/repetitive, these "shocks" to the lower body may contribute to overuse injury. The shocks imposed by different ballet maneuvers are largely unknown at this time, making it difficult to appreciate the physical stresses associated with different maneuvers. Therefore, the purpose of this study was to compare the impact accelerations associated with different common ballet maneuvers. METHODS: As part of this study, 11 adolescent ballet dancers performed 9 different common ballet maneuvers: (1) glissade, (2) pas de chat, (3) petit jeté, (4) petit assemblé, (5) grand assemblé, (6) grand jeté, (7) saut de chat, (8) changement, and (9) entrechat quatre. An inertial sensor secured to the pelvis was used to record the peak resultant acceleration during landings ("impact acceleration"). A Friedman test was conducted to compare impact accelerations across the maneuvers and Wilcoxon signed-rank tests were conducted as pairwise comparisons. RESULTS: The omnibus test indicated that there were differences in impact accelerations among the maneuvers (P < .001). In general, the glissade (2.08 ± 0.47g), pes de chat (2.33 ± 0.23g), petit jeté (2.42 ± 0.29g), and petite assemblé (2.54 ± 0.47g) tended to be the lower impact maneuvers; the grand assemblé (2.90 ± 0.41g), grand jeté (2.99 ± 0.33g), and saut de chat (3.13 ± 0.54g) tended to be the more moderate impact maneuvers; and the changement (4.10 ± 0.48g) and entrechat quatre (4.32 ± 0.52g) tended to be higher impact maneuvers. CONCLUSION: These findings may provide clinicians and dance instructors with greater insight regarding the physical stresses imposed by different ballet maneuvers.

Instructions Promoting an External Focus Are More Effective for Altering Impact Forces in Female Runners.

CONTEXT: Previous studies have found that instructions promoting an external focus (EF) tend to be more effective for movement pattern retraining compared to instructions promoting an internal focus (IF), for a variety of movement tasks. However, few studies have examined how different types of instructions affect running mechanics associated with running-related injury risk. Therefore, the purpose of this study was to compare the effects of instructions promoting different attentional foci on impact forces during running. DESIGN: Cross-sectional study. METHODS: Twenty uninjured female recreational runners ran at a self-selected speed with their typical pattern (no instructions condition) on an instrumented treadmill that measured ground reaction forces. Next, they were given 2 sets of instructions intended to alter their running pattern; one promoted an IF and the other promoted an EF. Repeated-measures analysis of variance was used to compare impact peaks and loading rates across the conditions (no instructions, IF, and EF), with post hoc tests conducted in the case of a significant omnibus test. RESULTS: There were differences among the conditions in the impact peaks (P < .001) and loading rates (P < .001). Impact peaks were lower for the IF (P = .002) and EF (P < .001) conditions compared to the no instructions condition. Loading rates were lower for the EF condition compared to the no instructions (P < .001) and IF (P < .001) conditions; there was no difference between the IF and no instructions conditions (P = .24). CONCLUSIONS: Our findings indicate that instructions promoting an EF may be more effective at reducing loading rates during running compared to instructions promoting an IF. Clinicians should consider these findings when attempting to retrain a runner's running pattern.

Physiological Demands of a Self-Paced Firefighter Air-Management Course and Determination of Work Efficiency.

Firefighters often complete air management courses (AMC) to assess the ability to tolerate personal protective equipment, appropriately manage the breathing system and assess occupational performance. Little information is known relative to the physiological demands of AMCs, nor how to assess work efficiency in order to characterize occupational performance and evaluate progress. PURPOSE: To assess the physiological demands of an AMC and examine differences across BMI categories. A secondary aim was to develop an equation to assess work efficiency in firefighters. METHODS: Fifty-seven firefighters (Women, n = 4; age: 37.2 ± 8.4 yr.; height: 182.0 ± 6.9 cm; body mass: 90.8 ± 13.1 kg; BMI: 27.8 ± 3.6 kg·m-2) completed an AMC per routine evaluation while wearing a department issued self-contained breathing apparatus and full protective gear. Course completion time, starting pounds per square inch (PSI) on the air cylinder, changes in PSI, and distance traveled were recorded. All firefighters were equipped with a wearable sensor integrated with a triaxial accelerometer and telemetry to assess movement kinematics, heart rate, energy expenditure, and training impulse. The AMC consisted of an initial section involving a hose line advance, rescue (body drag), stair climb, ladder raise, and forcible entry. This section was followed by a repeating loop, which consisted of a stair climb, search, hoist, and recovery walk. Firefighters repeated the course loop until the self-contained breathing apparatus air supply pressure reached 200 PSI, at which time they were instructed to lay down until the PSI reached zero. RESULTS: Average completion time was 22.8 ± 1.4 min, with a mean distance of 1.4 ± 0.3 km and an average velocity of 2.4 ± 1.2 m·s-1. Throughout the AMC, the mean heart rate was 158.7 ± 11.5 bpm equating to 86.8 ± 6.3% of the age-predicted max heart rate and a training impulse of 55 ± 3 AU. Mean energy expenditure was 464 ± 86 kcals and work efficiency was 49.8 ± 14.9 km·PSI-1·s. Regression analysis determined that fat-free mass index (R2 = 0.315; ß = -5.069), body fat percentage (R2 = 0.139; ß = -0.853), fat-free mass (R2 = 0.176; ß = -0.744), weight (R2 = 0.329; ß = -0.681), and age (R2 = 0.096; ß = -0.571) were significant predictors of work efficiency. CONCLUSIONS: The AMC is a highly aerobic task with near-maximal heart rates reached throughout the course. Smaller and leaner individuals achieved a higher degree of work efficiency during the AMC.

Predicting First-Time National Physical Therapy Examination Performance for Graduates of an Entry-Level Physical Therapist Education Program.

INTRODUCTION: The National Physical Therapy Examination (NPTE) is a standardized examination designed to assess competence after graduation from an entry-level physical therapist education program. REVIEW OF LITERATURE: Previous studies have identified applicant and student variables that are related to NPTE performance, with applicant variables reflecting performance before admission and student variables reflecting performance after admission. However, there are very few articles describing how these variables can be combined to predict NPTE performance. The purpose of this study was to develop, evaluate, and describe models to predict first-time NPTE scores and NPTE outcomes (pass vs fail), based on various applicant and student variables related to academic performance. SUBJECTS: Pre- and postadmission data and NPTE scores were recorded for 185 individuals who graduated from an entry-level physical therapist education program. METHODS: Multiple linear regression was used to develop a model to predict NPTE scores, and binary logistic regression was used to develop a model to predict NPTE outcomes (pass vs fail). RESULTS: A model including undergraduate prerequisite grade point average, grade point average in basic science courses taken during the program, and comprehensive examination scores combined to explain 30.9% of the variance in NPTE scores and accurately predicted NPTE outcomes (pass vs fail) 81.1% of the time. DISCUSSION: In general, our findings support the notion that prediction of NPTE performance should be based on a combination of applicant and student variables. The models described in this article could be used to identify students who may be likely to struggle on the NPTE, making it possible to provide additional support to these students. CONCLUSION: Various applicant and student variables related to academic performance can be combined to predict NPTE performance. The results of this study provide a framework for programs interested in applying models to predict NPTE performance.

Deficits in Dynamic Balance and Hop Performance Following ACL Reconstruction Are Not Dependent on Meniscal Injury History.

Background: Athletes often exhibit persistent deficits in dynamic balance and hop performance in their involved limb following ACL reconstruction. However, it is unclear how meniscal injury history affects inter-limb asymmetry. Purpose: The purpose of this study was to compare inter-limb asymmetry in dynamic balance and hop performance in athletes with and without a history of concomitant meniscal injury. Study Design: Cross-sectional study. Methods: Dynamic balance and hop test data were analyzed for 34 adolescent athletes who had undergone ACL reconstruction; 19 athletes had sustained an isolated ACL tear, while 15 had sustained an ACL tear along with a meniscus injury. Athletes who had sustained a meniscus injury were sub-divided into those who underwent a meniscal repair (n = 9) versus a partial meniscectomy (n = 6). Dynamic balance was assessed using the Y-Balance Test, while hop performance was assessed using the single and triple hop tests. Data were recorded at the time of return-to-sport testing (5-11 months post-surgery). For each variable, mixed-model analysis of variance, with a between-subjects factor of group (isolated ACL tear, meniscal repair, partial meniscectomy) and a within-subjects factor of limb (involved, uninvolved), was conducted. Results: The groups exhibited similar degrees of inter-limb asymmetry in dynamic balance and hop test performance, as there was not a group-by-limb interaction effect for the Y-Balance Test distances (p ≥ 0.43) or hop test distances (p ≥ 0.96). However, there was a main effect of limb for the anterior and posteromedial Y-Balance Test distances and the single and triple hop test distances (p ≤ 0.004). For each variable, performance was worse for the involved limb, compared to the uninvolved limb. Conclusion: It appears that deficits in dynamic balance and hop performance among adolescent athletes who have undergone ACL reconstruction are not dependent on meniscal injury/surgery history. Level of Evidence: 3.

The Effects of Cadence Manipulation on Joint Kinetic Patterns and Stride-to-Stride Kinetic Variability in Female Runners.

Altering running cadence is commonly done to reduce the risk of running-related injury/reinjury. This study examined how altering running cadence affects joint kinetic patterns and stride-to-stride kinetic variability in uninjured female runners. Twenty-four uninjured female recreational runners ran on an instrumented treadmill with their typical running cadence and with a running cadence that was 7.5% higher and 7.5% lower than typical. Ground reaction force and kinematic data were recorded during each condition, and principal component analysis was used to capture the primary sources of variability from the sagittal plane hip, knee, and ankle moment time series. Runners exhibited a reduction in the magnitude of their knee extension moments when they increased their cadence and an increase in their knee extension moments when they lowered their cadence compared with when they ran with their typical cadence. They also exhibited greater stride-to-stride variability in the magnitude of their hip flexion moments and knee extension moments when they deviated from their typical running cadence (ie, running with either a higher or lower cadence). These differences suggest that runners could alter their cadence throughout a run in an attempt to limit overly repetitive localized tissue stresses.

Female Athletes Exhibit Greater Trial-to-Trial Coordination Variability When Provided with Instructions Promoting an External Focus.

The purpose of this study was to examine how instructions promoting different attentional foci influence joint coordination patterns and trial-to-trial coordination variability during landing. Sixteen females performed drop landings with their typical technique (baseline) and after receiving instructions promoting an internal focus and an external focus. The coordination patterns, and trial-to-trial coordination variability, of the sagittal plane hip-knee, hip-ankle, and knee-ankle angle pairings were compared across conditions. While there was no difference in the joint coordination patterns among the conditions, subjects exhibited greater hip-ankle and knee-ankle trial-to-trial coordination variability for the external focus condition, vs. the baseline and internal focus conditions, which may help to explain the improved motor learning outcomes for athletes who train with an external focus.

Wrist pressure and angulation during keyboarding: Comparison between two common wrist supports.

BACKGROUND: Wrist pressure and angulation while working at a computer workstation have been associated with cumulative trauma disorders (CTDs) like carpal tunnel syndrome (CTS). OBJECTIVE: This quantitative, comparative study analyzed wrist pressure and angulation between two common wrist supports while typing at a standardized computer workstation. METHODS: A convenience sample of healthy young adults completed a five-minute typing task at a standardized workstation with no wrist support, with the ErgoBeads™ wrist support, and with an Elzo™ (memory foam) wrist support. Pressure mapping (Tekscan™)) and goniometry were used as quantitative measures to examine wrist pressure and wrist angulation during the typing task; descriptive and inferential statistics were performed to compare wrist angulation and wrist pressure between two supports. RESULTS: For the sample (n = 54), both wrist supports demonstrated a significant (p < 0.001) reduction in wrist extension as well as pressure compared to typing at the workstation with no support. There was no statistically significant difference in peak or mean pressure between the ErgoBeads™ and Elzo™ wrist supports (p = 0.99). Significant difference was identified ((p < 0.001) for wrist angle as participants exhibited less wrist extension using the ErgoBeads™ (x¯=12.56∘; SD = 3.32°) support as compared to the Elzo™ (x¯=19.25∘; SD = 3.77°) support. CONCLUSIONS: The results suggest that the ErgoBeads™ and Elzo™ memory foam wrist supports are effective for reducing pressure between the wrist and work surface while the ErgoBeads™ support may promote a more neutral angle of the wrist while typing.

Intra-rater reliability of goniometry to measure scapular protraction and retraction.

STUDY DESIGN: Observational, descriptive design. BACKGROUND: Despite scapular mobility being essential for the completion of activities of daily living (ADLs), there is currently no established, a reliable goniometric technique to measure scapular protraction and retraction. A proposed method has shown clinically significant inter-rater reliability for a goniometric technique for these measurements. PURPOSE: This observational descriptive study examined the intra-rater reliability of a goniometric technique to assess scapular protraction and retraction among a sample of healthy adults. METHODS: An occupational therapist who is a certified hand therapist (CHT) and an occupational therapy student used goniometry to measure the neutral (resting), protracted, and retracted positions of the right and left scapula for a sample of healthy young adults (n = 54; a total of 108 data points for each measurement). These measurements were compared to analyze intra-rater and inter-rater reliability. RESULTS: For measurements of the scapula in neutral, protraction, and retraction, the standard error of measure (SEM) for repeat measures by the expert and novice raters was < 4.5° and < 3.9° respectively and ICC values ranged from poor to moderate (0.37-0.63). The SEM for measures between evaluators was < 5.0° and the ICC was poor (0.16-0.35). Minimum detectable change (MDC) values as a percentage of the mean (% MDC) ranged between 15.9 and 43.7% for intra-rater reliability and 21.9-52.8% for inter-rater reliability. DISCUSSION: The results of the study were mixed; variance of less than 5° for repeat measures by the same rater and measures between raters suggest clinically acceptable reliability. However, variance as a proportion of available motion (%MDC) demonstrates a broader range both above and below the threshold of 30% suggested for rehabilitation assessments. CONCLUSION: There are few efficient, reliable techniques to measure scapular mobility in clinical practice. The absolute reliability of goniometry to measure scapular protraction and retraction is similar to measurements of other joints. However, additional research and possible refinement of the technique is recommended to further address relative reliability and validity.

The Effects of Increasing Cognitive Load on Support Limb Kicking Mechanics in Male Futsal Players.

Our objective was to examine the effects of cognitive load on support limb mechanics during a futsal kicking task. Twenty-one male futsal players completed kicks of a stationary ball without a secondary task (baseline), as well as kicks where cognitive load was increased by including a secondary cognitive task (dual-task) and requiring tracking of ball movement before the kick (pass). The athletes demonstrated less hip and knee flexion, higher loading rates, greater frontal and sagittal plane knee loading, and greater knee abduction for the dual-task condition, vs. baseline. They also demonstrated less knee flexion, higher loading rates, greater sagittal plane knee loading, and greater knee abduction for the pass condition, vs. baseline. It appears that cognitive load influences kicking mechanics.

Examining the Influence of Attentional Focus on the Effects of a Neuromuscular Training Program in Male Athletes.

ABSTRACT: Ghanati, HA, Letafatkar, A, Almonroeder, TG, and Rabiei, P. Examining the influence of attentional focus on the effects of a neuromuscular training program in male athletes. J Strength Cond Res 36(6): 1568-1575, 2022-Neuromuscular training programs that incorporate lower extremity strengthening, plyometric exercises, balance training, and movement retraining are recommended for anterior cruciate ligament injury prevention; however, there is a need to improve their effectiveness. The purpose of this study was to examine how athletes' attentional focus during training influences the effects of an 8-week neuromuscular training program on hip strength, single-leg landing mechanics, and hop performance. Sixty-six male athletes were randomly allocated to a group that trained with an internal focus, a group that trained with an external focus, or a control group. All athletes completed testing before (baseline) and after (posttesting) the 8-week period. Isokinetic hip strength, hip and knee kinematics and ground reaction forces during landing, and hop distance were examined as part of this study. Analysis of covariance was used to compare posttesting outcomes among the groups while accounting for group differences in baseline performance. The neuromuscular training program resulted in improved hip abduction strength, reduced hip adduction and internal rotation motion during landing, and increased hop distance for athletes who trained with an external focus. However, the program did not seem to influence hip strength, landing kinematics, or hop performance for athletes who trained with an internal focus. Our findings indicate that male athletes may benefit from completing a neuromuscular training program with an external focus vs. an internal focus. Trainers, coaches, and clinicians should consider using instructions that promote an external focus when implementing neuromuscular training programs with male athletes.

Kinetic Asymmetry During a Repetitive Tuck Jump Task in Athletes with a History of Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Athletes who have undergone anterior cruciate ligament reconstruction typically exhibit relatively high/rapid loading of their uninvolved limb during bilateral landing and jumping (vs. their limb that underwent reconstruction), which may place their uninvolved limb at risk for injury. However, previous studies have only examined forces and loading rates for tasks involving an isolated land-and-jump. PURPOSE: The purpose of this study was to examine bilateral landing and jumping kinetics during performance of a repetitive tuck jump task in athletes who had undergone anterior cruciate ligament reconstruction and completed rehabilitation. STUDY DESIGN: Cross-sectional study. METHODS: Nine athletes (four males, five females) participated in this study. All participants had undergone successful unilateral anterior cruciate ligament reconstruction, had completed post-operative rehabilitation, and were in the process of completing return-to-sport testing. Athletes performed a repetitive tuck jump task for 10 seconds, while ground reaction forces were recorded for their uninvolved and involved limbs via separate force platforms. Two-way analysis of variance, for within-subjects factors of limb and cycle, was performed for the impact forces, loading rates, and propulsive forces from the first five land-and-jump cycles completed. RESULTS: There was not a limb-by-cycle interaction effect or main effect of cycle for the impact forces, loading rates, or propulsive forces; however, there was a main effect of limb for the impact forces (F(1, 8) = 14.64; p=0.005), loading rates (F(1, 8) = 5.60; p=0.046), and propulsive forces (F(1, 8) = 10.38; p=0.012). Impact forces, loading rates, and propulsive forces were higher for the uninvolved limb, compared to the involved limb, over the five land-and-jump cycles analyzed. CONCLUSION: The athletes in this study consistently applied higher and more rapid loads to their uninvolved limb over multiple land-and-jump cycles. This may help to explain the relatively high injury rates for the uninvolved limb in athletes who have returned to sport following anterior cruciate ligament reconstruction.

The influence of step-down technique on lower extremity mechanics during curb descent.

When stepping down from a curb, individuals typically make initial ground contact with either their rearfoot or forefoot. The purpose of this study was to compare vertical ground reaction forces, lower extremity mechanics, and intra-limb work distribution when individuals adopt a rearfoot technique vs. a forefoot technique, during simulated curb descent. Sixteen subjects stepped down from a platform with both a rearfoot and a forefoot technique. Vertical ground reaction forces and sagittal plane joint kinematics and kinetics were examined for the lead limb during the step-down task. Paired t-tests were used for comparison. Subjects demonstrated greater ankle joint power and negative work, and less hip joint power and negative work, with the forefoot technique vs. the rearfoot technique. Total lower extremity negative work was greater for the forefoot technique vs. the rearfoot technique. The percent contribution to the total negative work was greater for the ankle joint, and less for the hip and knee joints, with the forefoot technique vs. the rearfoot technique. The results of this study may provide insight into how curb descent technique can be modified to alter lower extremity loading.

Establishing Normative Values for Inter-Limb Kinetic Symmetry During Landing in Uninjured Adolescent Athletes.

BACKGROUND: Assessment of inter-limb kinetic symmetry during landing could provide valuable insights when working with athletes who have undergone anterior cruciate ligament reconstruction. However, it is difficult to determine if the asymmetry exhibited by an injured athlete is excessive or within a range that is similar to uninjured athletes, until normative values are established. PURPOSE: The purpose of this study was to establish normative values for inter-limb impact force symmetry in uninjured adolescent athletes. In addition, an example is provided of how these normative values could be used to identify athletes who exhibit atypically high levels of asymmetry following anterior cruciate ligament reconstruction. STUDY DESIGN: Cross-sectional study. METHODS: One hundred and thirty-six uninjured athletes completed drop vertical jumps and countermovement jumps while force plates recorded ground reaction forces. Symmetry indices captured inter-limb symmetry in impact forces during landing for both tasks. These symmetry indices were also combined to create an index that captured symmetry across both tasks. Normative values were established using the uninjured athletes' data. Eleven athletes who had undergone anterior cruciate ligament reconstruction and been cleared to return to landing and jumping performed the same tasks and their data were compared to the results for the uninjured group. RESULTS: Measures of central tendency, variability, percentiles, and outliers were calculated/identified based on the uninjured athletes' symmetry indices. Six of the 11 injured athletes exhibited atypically high symmetry index values. CONCLUSION: The normative values established as part of this study may serve as a basis for identifying athletes who exhibit atypically high levels of inter-limb impact force asymmetry during jumping tasks following anterior cruciate ligament reconstruction. LEVEL OF EVIDENCE: 3b.