Strides to Achieve a Stable Symmetry Index During Running

Context: The quality of running mechanics is often characterized by limb pattern symmetry and used to support clinical decisions throughout the rehabilitation of lower-extremity injuries. It is valuable to ensure that gait analyses provide stable measures while not asking an individual to complete an excessive number of running strides. The present study aimed to determine the minimum number of strides required to establish a stable mean symmetry index (SMSI) of discrete-level measures of spatiotemporal parameters, joint kinematics, and joint kinetics. Further, the study aimed to determine if differences occurred between random and consecutive strides for directional and absolute symmetry indices. Design: Descriptive laboratory study. Methods: A sequential average was used to determine how many strides were required to achieve a SMSI within a 60-second trial. Multiple 2-factor repeated-measure analysis of variances were used to determine if differences between bins of strides and symmetry calculations were significantly different. Results: A median SMSI was achieved in 15 strides for all biomechanical variables. There were no significant differences (P > .05) found between consecutive and random bins of 15 strides within a 60-second trial. Although there were significant differences between symmetry calculation values for most variables (P < .05), there appeared to be no systematic difference between the numbers of strides required for stable symmetry for either index. Conclusions: As 15 strides were sufficient to achieve a SMSI during running, a continued emphasis should be placed on the number of strides collected when examining interlimb symmetry.

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Influences of Different Drop Height Training on Lower Extremity Kinematics and Stiffness during Repetitive Drop Jump

Applied Bionics and Biomechanics ◽

10.1155/2021/5551199 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

I-Lin Wang ◽

Yi-Ming Chen ◽

Ke-Ke Zhang ◽

Yu-Ge Li ◽

Yu Su ◽

...

Keyword(s):

Lower Extremity ◽

Lower Extremity Injury ◽

Repeated Measure ◽

Drop Height ◽

Drop Jump ◽

Extremity Injury ◽

Lower Extremity Injuries ◽

Performance Training ◽

Drop Jumps ◽

Extremity Injuries

Drop jump (DJ) is often used as a plyometric exercise to improve jumping performance. Training from improper drop heights and for improper durations lead to unfavorable biomechanical changes in the lower extremities when landing, which result in reduced training effects and even lower extremity injuries. Purpose. To study the effects of repeated DJ training at drop heights of 30 cm, 40 cm, and 50 cm (drop jump height (DJH) 30, DJH40, and DJH50) on lower extremity kinematics and kinetics. The 1st, 50th, 100th, 150th, and 200th DJs (DJ1, DJs50, DJs100, DJs150, and DJs200) were recorded by using a BTS motion capture system and force platform. The MATLAB software was used to compare the kinematic and stiffness data of DJ1, DJs50, DJs100, DJs150, and DJs200 with one-way ANOVA repeated measure. If there were significant differences, the LSD method was used for post hoc comparisons. Methods. Twenty healthy male Division III athlete volunteers were selected as subjects, and 200 drop jumps (DJs200) were performed from DJH30, DJH40, and DJH50. Results. The jumping height (JH), contact time (CT), and GRF increased with drop height, and the stiffness of the legs and ankle at DJH30 was higher than that at DJH40 and DJH50 ( p < 0.05 ). Conclusion. Within DJs200, training at DJH50 yield the high impact easily leads to lower extremity injury; training at DJH30 can increase the stiffnesses of the legs and ankle joints, thus effectively utilizing the SSC benefits to store and release elastic energy, reducing the risk of lower extremity musculoskeletal injury. Therefore, coaches can choose different drop heights and training quantities for each person to better prevent lower extremity injury.

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Judgment and Approach for Management of Severe Lower Extremity Injuries

Clinics in Plastic Surgery ◽

10.1016/s0094-1298(20)30851-8 ◽

1991 ◽

Vol 18 (3) ◽

pp. 525-543 ◽

Cited By ~ 2

Author(s):

Robert L. Walton ◽

Douglas M. Rothkopf

Keyword(s):

Lower Extremity ◽

Lower Extremity Injuries ◽

Extremity Injuries

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Concussion in National Football League Athletes Is Not Associated With Increased Risk of Acute, Noncontact Lower Extremity Musculoskeletal Injury

Orthopaedic Journal of Sports Medicine ◽

10.1177/23259671211003491 ◽

2021 ◽

Vol 9 (5) ◽

pp. 232596712110034

Author(s):

Toufic R. Jildeh ◽

Fabien Meta ◽

Jacob Young ◽

Brendan Page ◽

Kelechi R. Okoroha

Keyword(s):

Lower Extremity ◽

National Football League ◽

Field Performance ◽

Return To Play ◽

Lower Extremity Injury ◽

Extremity Injury ◽

Lower Extremity Injuries ◽

Increased Risk ◽

Extremity Injuries ◽

And Control

Background: Impaired neuromuscular function after concussion has recently been linked to increased risk of lower extremity injuries in athletes. Purpose: To determine if National Football League (NFL) athletes have an increased risk of sustaining an acute, noncontact lower extremity injury in the 90-day period after return to play (RTP) and whether on-field performance differs pre- and postconcussion. Study Design: Cohort study, Level of evidence, 3. Methods: NFL concussions in offensive players from the 2012-2013 to the 2016-2017 seasons were studied. Age, position, injury location/type, RTP, and athlete factors were noted. A 90-day RTP postconcussive period was analyzed for lower extremity injuries. Concussion and injury data were obtained from publicly available sources. Nonconcussed, offensive skill position NFL athletes from the same period were used as a control cohort, with the 2014 season as the reference season. Power rating performance metrics were calculated for ±1, ±2, and ±3 seasons pre- and postconcussion. Conditional logistic regression was used to determine associations between concussion and lower extremity injury as well as the relationship of concussions to on-field performance. Results: In total, 116 concussions were recorded in 108 NFL athletes during the study period. There was no statistically significant difference in the incidence of an acute, noncontact lower extremity injury between concussed and control athletes (8.5% vs 12.8%; P = .143), which correlates with an odds ratio of 0.573 (95% CI, 0.270-1.217). Days (66.4 ± 81.9 days vs 45.1 ± 69.2 days; P = .423) and games missed (3.67 ± 3.0 vs 2.9 ± 2.7 games; P = .470) were similar in concussed athletes and control athletes after a lower extremity injury. No significant changes in power ratings were noted in concussed athletes in the acute period (±1 season to injury) when comparing pre- and postconcussion. Conclusion: Concussed, NFL offensive athletes did not demonstrate increased odds of acute, noncontact, lower extremity injury in a 90-day RTP period when compared with nonconcussed controls. Immediate on-field performance of skill position players did not appear to be affected by concussion.

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Comparison of Mean Platelet Counts in Preterm Infants with and without Retinopathy of Prematurity

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18073783 ◽

2021 ◽

Vol 18 (7) ◽

pp. 3783

Author(s):

Zi Di Lim ◽

Edwin Pheng ◽

Evelyn Tai Li Min ◽

Hans Van Rostenberghe ◽

Ismail Shatriah

Keyword(s):

Risk Factors ◽

Retinopathy Of Prematurity ◽

Primary Source ◽

Analysis Of Covariance ◽

Repeated Measure ◽

Platelet Counts ◽

Related Risk ◽

Measure Analysis ◽

Repeated Measure Analysis ◽

Over Time

Platelets are a primary source of pro- and anti-angiogenic cytokines. However, the evidence of their role in retinopathy of prematurity (ROP) is controversial. This retrospective study aimed to compare mean weekly platelet counts between infants with and without ROP over the first 6 weeks of life. A total of 93 infants matched by gestational age and birth weight were recruited (31 with ROP, 62 without ROP). Weekly mean platelet counts and other related risk factors were documented. The repeated measure analysis of variance (ANOVA) and the repeated measure analysis of covariance (ANCOVA) were used to compare mean platelet counts over time between the two groups, with and without adjusting for confounders. We found significant differences in the weekly mean platelet counts of infants with and without ROP over the first 6 weeks of life (p = 0.002). These differences disappeared after adjusting for covariates (p = 0.489). Lower mean platelet counts in ROP infants are not directly related to ROP, but rather to the presence of other risk factors for ROP, such as culture-proven sepsis, blood transfusion and bronchopulmonary dysplasia.

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EFFECTIVENESS OF PRE-SEASON PHYSICAL PERFORMANCE TESTS IN IDENTIFYING IN-SEASON LOWER EXTREMITY INJURIES IN ADOLESCENT GYMNASTS

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967121s00141 ◽

2021 ◽

Vol 9 (7_suppl3) ◽

pp. 2325967121S0014

Author(s):

Danielle A Farzanegan ◽

Emily Francione ◽

Nicole Melfi

Keyword(s):

Lower Extremity ◽

Physical Performance ◽

Performance Tests ◽

Kinetic Chain ◽

Chi Square ◽

Balance Test ◽

Lower Extremity Injuries ◽

Common Location ◽

Acute Injuries ◽

Extremity Injuries

Background: Artistic competitive gymnastics results in a wide, unique spectrum of injuries. Due to the high number of injuries and the current lack of research related to pre-competitive testing in adolescent gymnasts, it is crucial to find a method to predict the likelihood of an athlete sustaining an in-season injury. Purpose: The purpose of this study was to 1) describe the frequency and type of pre-season and in-season injuries, 2) determine if there were differences in physical performance tests between those who had a lower extremity (LE) injury in-season and those who did not, and 3) determine if there were differences in age, level, sex, BMI, sport modifications, previous injury, and current injury between those who had a LE injury and those who didn’t. Methods: Thirty-seven adolescent gymnasts (average age: 12.81 years) were included with levels ranging from 5 (novice) to 10 (elite). Participants (15 males and 22 females) were surveyed for previous and current injury. The athletes completed a performance battery before the competition season including: Lower Quarter Y-Balance Test (LQYBT), Closed Kinetic Chain dorsiflexion (CKCDF), single hop (SH), triple hop (TH), and the Functional Movement Screen (FMS). Follow-up data was collected at the end of the competitive season for comparison. The data was analyzed using descriptive methods and comparative analyses including chi-square and independent t-tests with an alpha level set at .05. Results: Sixty-five percent reported an injury in the last year and seventy-eight percent reported pre-season injuries at testing day. The most common location for pre-season injury was the ankle/foot (24% and 31% respectively). There were no differences between injured and non-injured athletes when comparing asymmetries in CKCDF, LQYBT posteromedial or posterolateral reach, hop testing, or FMS. The LQYBT-anterior scores were significantly different at p=.049 between the injured versus uninjured groups, with 91% of the in-season injury group having a difference <4cm. Similarly, the LQYBT-composite score using a cut-off of 95% was significant at p=.043 with those >95% category being more likely to get injured. There were no significant differences in demographic information comparing injury occurrence. Conclusion: The tested physical performance battery may be useful in tracking gymnasts over time, but may not be beneficial in forecasting injuries in a sport with high percentages of acute injuries. The collected injury volume may not be reflective of a standard season as COVID-19 decreased the number of competitions. Additional research to identify athletes at risk for injury requires further investigation.

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Association Between Ball-Handling Versus Defending Actions and Acute Noncontact Lower Extremity Injuries in High School Basketball and Soccer

The American Journal of Sports Medicine ◽

10.1177/0363546514564541 ◽

2015 ◽

Vol 43 (4) ◽

pp. 802-807 ◽

Cited By ~ 9

Author(s):

Scott M. Monfort ◽

R. Dawn Comstock ◽

Christy L. Collins ◽

James A. Onate ◽

Thomas M. Best ◽

...

Keyword(s):

High School ◽

Lower Extremity ◽

Lower Extremity Injuries ◽

Extremity Injuries

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ORTHOPEDIC INJURIES IN ADOLESCENT GYMNASTS: A SYSTEMATIC REVIEW

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967121s00117 ◽

2021 ◽

Vol 9 (7_suppl3) ◽

pp. 2325967121S0011

Author(s):

Katie Kim ◽

Michael Saper

Keyword(s):

Lower Extremity ◽

Upper Extremity ◽

Weight Bearing ◽

The Body ◽

Adolescent And Young Adult ◽

Body Region ◽

Lower Extremity Injuries ◽

Common Location ◽

Orthopedic Injuries ◽

Extremity Injuries

Background: Gymnastics exposes the body to many different types of stressors ranging from repetitive motion, high impact loading, extreme weight bearing, and hyperextension. These stressors predispose the spine and upper and lower extremities to injury. In fact, among female sports, gymnastics has the highest rate of injury each year. Purpose: The purpose of this study was to systematically review the literature on location and types of orthopedic injuries in adolescent (≤20 years) gymnasts. Methods: The Pubmed, Medline, EMBASE, EBSCO (CINAHL) and Web of Science databases were systematically searched according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines to identify all studies reporting orthopedic injuries in adolescent and young adult gymnasts. All aspects of injuries were extracted and analyzed including location, type and rates of orthopedic injuries. Results: Screening yielded 22 eligible studies with a total of 427,225 patients. Twenty of 22 studies reported upper extremity injuries of which four specifically focused on wrist injuries. Eight studies reported lower extremity injuries. Nine studies reported back/spinal injuries. Seven studies investigated each body location of injury; one study reported the upper extremity as the most common location for injury and six studies reported the lower extremity as the most common location for injury. Of those seven studies, five (23%) reported sprains and strains as the most common injury. One study reported fractures as the most common injury. Conclusion: There is considerable variation in reported injury location. Some studies focused specifically on the spine/back or wrist. The type of gymnastics each patient participated in was also different, contributing to which area of the body was more heavily stressed, or lacking. Current literature lacks data to fully provide evidence regarding which body region is more frequently injured and the type of injury sustained.

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