Effects of Backward Walking on Hamstring Flexibility and Low Back Range of Motion

The purpose of the study was to examine the effects of backward walking on hamstring flexibility and low back range of motion. Ten healthy female volunteers (29.9±10.0 yr; 165.1±8.2 cm; 68.53±18.4 kg) completed pre-post laboratory testing surrounding a 4-week intervention of backward walking. During the pretest, each participant walked forward on a treadmill at a preferred velocity for 3-5 min. A biaxial electrogoniometer was secured externally to the low back and a sit-and-reach test was performed. Each participant then walked backward at their preferred pace on a treadmill for 10 min, during which time low back motion data were obtained (1000 Hz). Following the pretest, participants completed an intervention of walking backward at a self-selected velocity for 10-15 min/day, 4 days/week. This was followed by a posttest, using the exact protocol as the pretest. Dependent variables consisted of pre-post measures of: 1) backward walking velocity (VEL), 2) flexibility of the hamstrings (HF), low back sagittal plane range of motion (sROM), and low back coronal plane range of motion (cROM). Correlated t-tests (α = 0.05) with Bonferroni correction identified significant (p \u3c 0.001) differences in VEL and HF. Low back motion parameters (sROM, cROM) were not significantly different (p \u3e 0.0125) following the intervention. Results of the study suggest that a 4-week intervention of backward walking appears to provide an appropriate stimulus for an increase in flexibility of the hamstrings. A possible interaction between VEL and sROM or cROM limited the interpretation of observed non-significant changes in low back motion

ELECTRODYNOGRAM FORCE ANALYSIS IN CROSSCOUNTRY SKIING

Effectiveness of the Langer Electrodynogram (EDG) force analysis system in the cross country ski diagonal stride was tested in a preliminary study. The objective was to utilize the EDG to investigate temporal patterns of the stride performed on level terrain

A Comparative Evaluation of Gait between Children with Autism and Typically Developing Matched Controls

Anecdotal reports suggest children with autism spectrum disorder (ASD) ambulate differently than peers with typical development (TD). Little empirical evidence supports these reports. Children with ASD exhibit delayed motor skills, and it is important to determine whether or not motor movement deficits exist during walking. The purpose of the study was to perform a comprehensive lower-extremity gait analysis between children (aged 5–12 years) with ASD and age- and gender-matched-samples with TD. Gait parameters were normalized to 101 data points and the gait cycle was divided into seven sub-phases. The Model Statistic procedure was used to test for statistical significance between matched-pairs throughout the entire gait cycle for each parameter. When collapsed across all participants, children with ASD exhibited large numbers of significant differences (p \u3c 0.05) throughout the gait cycle in hip, knee, and ankle joint positions as well as vertical and anterior/posterior ground reaction forces. Children with ASD exhibited unique differences throughout the gait cycle, which supports current literature on the heterogeneity of the disorder. The present work supports recent findings that motor movement differences may be a core symptom of ASD. Thus, individuals may benefit from therapeutic movement interventions that follow precision medicine guidelines by accounting for individual characteristics, given the unique movement differences observed

The Influence of Sport-Related Concussion on Lower Extremity Injury Risk: A Review of Current Return-to-Play Practices and Clinical Implications

International Journal of Exercise Science 13(3): 873-889, 2020. Sport-related concussions (SRCs) are now classified as a major health concern affecting athletes across all sporting levels, with recent evidence suggesting upwards of 3.8 million SRCs occur each year. Multiple injury surveillance datasets have recently determined that athletes post-SRC, compared to non-concussed counterparts, are at greater risk for lower extremity (LE) injury beyond the resolution of traditional SRC assessment batteries. However, it is presently uncertain if common clinical practices (symptom reporting, neuropsychological (NP) examination, and static postural control analysis) can determine athletes at risk for LE injury following an SRC. A comprehensive review of the literature determined that these tools may not reveal subtle cognitive and neuromuscular deficits that lead to subsequent LE injury during dynamic sporting tasks. Current return-to-play (RTP) protocols should consider clarifying the addition of specific objective locomotor analysis, such as gait tasks and sport-specific maneuvers, to determine the risk of LE injury after an athlete has sustained an SRC

The Relationship Between Concussion History and Sex on Lower Extremity Biomechanics During a Cutting Task

Athletes with a history of sports related concussion (SRC) have been shown to exhibit lower extremity (LE) mechanics during high impact landing tasks that are conducive to increased injury risk. The underlying cause, and extent of this phenomena is currently unknown. PURPOSE: The purpose of this study was to analyze the relationship between SRC history and sex on LE biomechanics during a land-and-cut task. METHODS: College athletes with a history of SRC and a control group of healthy athletes matched by sport, position, sex, and age were recruited for this study. Both groups were comprised of 9 males and 11 females. Athletes performed an unanticipated land-and-cut task. The task consisted of each athlete standing on a 60 cm box with a visual stimulus positioned three meters away from the athlete. Various colors (green, pink, blue, and red) were presented as the visual stimulus. Athletes were instructed to only respond to a green or red light. When a red or green light was shown, athletes were instructed to step off the box, land on both limbs and perform a 45-degree cutting movement to the left or right, respectively. Two separate point biserial correlations were conducted (one for each sex) correlating group (0 = control, 1 = SRC) with the following dependent variables: vertical ground reaction force (vGRF), peak knee extensor moment (pKEM), peak knee abduction moment (pKAM), peak ankle dorsiflexion angle (pDF), peak knee flexion angle (pKFA), and peak knee abduction angle (pKA). A linear regression equation was obtained for significant correlations. RESULTS: There was a significant negative moderate correlation between group and KF in males (r = -.69, p \u3c .01). There were no other significant correlations between group and LE biomechanical variables in either males or females (p \u3e .05). A linear regression analysis showed SRC history was a significant predictor of KF (KF = 63.71 – 12.43(group); R2 = .473, p = .002) CONCLUSION: Males in the SRC group were associated with lower KF. Specifically, the regression analysis indicated that males with an SRC history had a predicted 12.4 degree decrease in KF during the land-and-cut task. This suggests previously concussed males may be at increased risk for LE injury

Interactive effects between group and single-subject response patterns

A two-part study was undertaken to investigate the effects of movement experiences on lower extremity function during impact activities. Group and single-subject performances were evaluated for a total of 12 male volunteers during landing (Study I) and running (Study II) activities. Standard biomechanical techniques were used to obtain kinematic (200 Hz) and kinetic (1000 Hz) data during soft, normal and stiff-knee landings (Study I) and for under, normal, and over-stride running (Study II). Performance trials were tested for normality, condition differences were documented and multiple regression models were computed to predict the first (F1) and second (F2) maximum vertical forces during landing and the maximum impact force (IF) during running. Results of the study identified condition differences with no deviations from normality, thereby achieving the goal of increasing performance heterogeneity to benefit the modeling procedures. Group regression model results for F1, F2 and IF each identified a single predictor variable that accounted for 74.7, 98.6 and 81.6% explained variance (EV), respectively. Single-subject predictors and EV values varied and demonstrated a number of different strategies. The group models were not representative of any of the individual subjects\u27 performances and indicate that group models can describe a mythical average performer. These results suggest that researchers must be cautious when evaluating group performance patterns

The Relationship Between Concussion History And Lower Extremity Biomechanics During A Land And Cut Task

In high impact landing tasks, athletes with a history of sports related concussion (SRC) have been found to demonstrate lower extremity (LE) biomechanics that are associated with elevated injury risk. However, the exact relationships between SRC history and LE biomechanics are inconclusive. PURPOSE: The purpose of this study was to investigate the relationship between SRC history and LE biomechanics during a cutting task. METHODS: A cohort of athletes with a history of SRC (n=20) and a control group of healthy athletes (n=20) were recruited for this study. The control group were matched by age, sex, and sport. Athletes performed an unanticipated land and cut task. Athletes stood on a 60 cm box and focused on a visual light positioned three meters away from them. The light displayed green, pink, blue, or red. Athletes were instructed to step off the box, land on both limbs, and perform a 45-degree cutting maneuver to left or right when they saw red or green light respectively. A point biserial correlation was conducted correlating group (0 = control, 1 = SRC) with the following dependent variables: dominant limb ground reaction force (D_GRF), dominant limb ankle dorsiflexion angle (D_DF), dominant limb knee flexion angle (D_KFA), dominant limb knee flexion moment (D_KFM), dominant limb knee abduction angle (D_KAA), and dominant limb knee abduction moment (D_KAM). A linear regression equation was obtained for any significant correlations. RESULTS: There was a small significant negative correlation between group and KFA (r = -.342, p \u3c .01). There were no other significant correlations between group and LE biomechanical variables (p \u3e .05). A linear regression analysis showed SRC history as a significant predictor of KFA (KFA = 60.24 - 6.16(group); R2 = 0.117, p = .03). CONCLUSION: The SRC group was associated with lower KFA. According to our regression analysis, athletes with an SRC history had predicted a 6.2 degree decrease in KFA compared to the control group during the land and cut task. Furthermore, approximately 12% of the variance in KFA can be explained by SRC. This suggests that previously concussed athletes may be at a higher risk for LE injury. Further research in this area is needed to confirm this relationship

Modifying the Diabetes Prevention Program to Adolescents in a School Setting: A Feasibility Study

The growing epidemic of overweight children has led to a higher prevalence of youth being diagnosed with diabetes, particularly type 2 diabetes. The current study modified the Diabetes Prevention Program (DPP) for use with 7th–10th graders in a school setting. The DPP is an evidence-based lifestyle intervention program that has been translated successfully in various adult settings. Yet the feasibility of modifying the DPP for use with middle and high school students has not been documented. A multidisciplinary university research team collaborated with a local charter school to include a modified DPP as part of the curriculum for one semester. Pre- and posttests included food knowledge, health locus of control, BMI, and performance on the 12-minute Cooper walk/run test. Findings suggest tentatively that the modified DPP was successful at increasing food knowledge and awareness of more rigorous physical activity as well as their association to improved health outcomes. Equally as important, results demonstrate that it is feasible to conduct interventions targeting healthy weight among adolescents in school-based settings by incorporating them in the curriculum.</jats:p

Influence of Cognitive Performance on Musculoskeletal Injury Risk: A Systematic Review

Background: While a large number of studies have investigated the anatomic, hormonal, and biomechanical risk factors related to musculoskeletal (MSK) injury risk, there is growing evidence to suggest that cognition is an important injury contributor in the athletic population. A systematic review of the available evidence regarding the influence of cognitive performance on MSK injury risk has yet to be published in the sports medicine literature. Purpose/Hypothesis: The purpose was to determine the effects of cognition on (1) MSK biomechanics during sports-specific tasks and (2) MSK injury occurrence in the athletic population. It was hypothesized that athletes with lower cognitive performance would demonstrate biomechanical patterns suggestive of MSK injury risk and that injured athletes would perform worse on baseline measures of cognition as compared with their noninjured counterparts. Study Design: Systematic review. Methods: PubMed and SPORTDiscus were searched from January 2000 to January 2020. Manual searches were performed on the reference lists of the included studies. A search of the literature was performed for studies published in English that reported MSK biomechanics as a function of cognitive performance and MSK injury occurrence after baseline measures of cognition. Two independent reviewers extracted pertinent study data in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2009 guidelines and assessed study quality using the Quality Assessment Tool for Observational Cohort and Cross-sectional Studies from the National Institutes of Health. A meta-analysis was not performed, owing to the heterogeneous nature of the study designs. Results: Ten studies met inclusion criteria: 4 cognition–MSK biomechanics studies and 6 cognition–MSK injury studies. All 4 cognition–MSK biomechanics studies demonstrated that worse performance on measures of cognition was associated with lower extremity MSK biomechanical patterns suggestive of greater risk for MSK injury. The majority of the cognition–MSK injury studies demonstrated that injured athletes significantly differed on baseline cognition measures versus matched controls or that cognitive performance was a significant predictor for subsequent MSK injury. Conclusion: Although the literature exploring cognitive contributions to MSK injury risk is still in its infancy, it is suggested that sports medicine personnel conduct baseline assessments of cognition—in particular, reaction time and working memory—to identify which athletes may be at elevated risk for future MSK injury

The Effect of Exercise Modality on Age-related Changes Observed During Running

Introduction: With the increase in participation by older adults in endurance events, research is needed to evaluate how exercising throughout the lifespan can afect the aging process regarding gait and mobility. The purpose of this study was to determine how the type of exercise modality one participates in will affect age-related declines observed during running. Methods: Fifty-six individuals between the ages of 18–65 who considered running, resistance training or cycling/ swimming as their primary form of activity participated in this study. Kinematics were captured using a 10-camera motion capture system while participants ran at a controlled pace of 3.5 m/s (±5%) over a 10-m runway with force platforms collecting kinetic data. Eight successful trials were chosen for analysis. A one-way ANOVA assessed differences in mean kinematic and kinetic variables of interest between physical activity groups (α=0.05). Results: Older resistance trainers exhibited greater maximal knee power compared to older runners. No other group differences were observed. Conclusion: Despite type of exercise modality, regularly participating in exercise has positive effects. This is evident through the preservation of the function of the lower extremity with age, specifcally function of the ankle, and its contribution to healthy movement patterns