Coordination variability (CV) is commonly analyzed to understand dynamical qualities of human locomotion. The purpose of this study was to develop guidelines for the number of trials required to inform the calculation of a stable mean lower limb CV during overground locomotion. Three-dimensional lower limb kinematics were captured for 10 recreational runners performing 20 trials each of preferred and fixed speed walking and running. Stance phase CV was calculated for 9 segment and joint couplings using a modified vector coding technique. The number of trials required to achieve a CV mean within 10% of 20 strides average was determined for each coupling and individual. The statistical outputs of mode (walking vs running) and speed (preferred vs fixed) were compared when informed by differing numbers of trials. A minimum of 11 trials were required for stable mean stance phase CV. With fewer than 11 trials, CV was underestimated and led to an oversight of significant differences between mode and speed. Future overground locomotion CV research in healthy populations using a vector coding approach should use 11 trials as a standard minimum. Researchers should be aware of the notable consequences of an insufficient number of trials for overall study findings.
Hannah E. Wyatt, Gillian Weir, Carl Jewell, Richard E.A. van Emmerik, and Joseph Hamill
Kyndell R. Crowell, Ryan D. Nokes, and Nicole L. Cosby
Clinical Scenario: Dynamic knee valgus (DKV) is a mechanical alteration in the knee that leads to increased risk of injury. Weakness of hip musculature in hip abduction (HABD), extension (HEXT), and external rotation (HER) may contribute to increased DKV in single-leg landing tasks. Focused Clinical Question: Is decreased hip strength associated with an increase in DKV during a single-leg landing task in collegiate female athletes? Summary of Key Findings: Three studies were included: One randomized control trial (RCT), one cohort study, and one case-control. All three studies found that decreases in HABD and HER strength contributed to increased DKV during single-leg landing tasks. One study also found that the hip extensors contribute to controlling hip adduction, a common factor in many mechanisms of injuries. These three studies recommended strengthening HABD, HEXT, and HER to decrease DKV and reduce the risk of injury at the knee. Clinical Bottom Line: Weak HABD, HEXT, and HER contribute to increased DKV in college female athletes, but strengthening HABD, HEXT, and HER can lead to decreases in DKV and, overall, reduce the risk of injury at the knee. Strength of Recommendation: These articles were graded with a level of evidence of III or higher, giving a grade of B strength of recommendation that weak HABD, HEXT, and HER are associated with increased DKV in collegiate female athletes.
Hiromichi Usuki, Nealy Grandgenett, Sofia Jawed-Wessel, Adam B. Rosen, and Melanie L. McGrath
While Brazilian jiu-jitsu (BJJ) has a rate of injury similar to other combat sports, there is little information on the types of injuries sustained by BJJ athletes. The purpose of this study was to assess demographic information, participation rates, injuries, and medical care in BJJ athletes over a 12-month period. Seventy-eight athletes (75.0%) reported 136 injuries in the past year; however, medical attention was only sought for 59 (43.4%) of those injuries. No significant association was found between each demographic variable and injury prevalence. Despite the fact that a majority of BJJ athletes reported suffering an injury within the past year, slightly less than half of these injured athletes sought medical care. There was no difference in injury prevalence between belt ranks.
Kelly M. Cheever, W. Geoffrey Wright, Jane McDevitt, Michael Sitler, and Ryan T. Tierney
The objective of this study was to explore the correlation between preseason measures of cervical sensorimotor function and musculoskeletal injury rates across a contact sport season. The authors hypothesized that athletes with higher sensorimotor dysfunction at baseline would be more likely to suffer an injury. The authors further hypothesized that contact sport participation would lead to greater changes in cervical sensorimotor function across a sport season compared with noncontact controls. Forty-nine collegiate club athletes (26 rugby and 23 noncontact controls) participated in a cohort study. Low positive correlations between baseline sign and symptom severity (r = .383), and score (r = .344), and cervical joint position error (r = .385–.425) and time loss injury were observed. Combining sign and symptom severity score and the neck reposition error predicted musculoskeletal injury status with 80.8% accuracy (area under the curve = 0.80, p = .003). The results suggest preseason deficits in cervical sensorimotor function may be related to future musculoskeletal injury risk. Sign and symptom severity score, Neck Disability Index score, and cervical joint position error can help identify athletes requiring more comprehensive cervical spine assessment that may benefit from preventative intervention.
Giacomo Farì, Stefano Di Paolo, Domenico Ungaro, Gianluca Luperto, Eleonora Farì, and Francesca Latino
Background: Sport activities were interrupted due to a quarantine imposed to limit the spread of Coronavirus disease 2019 (COVID-19) in Italy. This study aimed to describe the impact of COVID-19 on sports and on daily activities in an Italian cohort of school children signed up in a football school. Methods: A total of 44 children from an Italian football school were enrolled. An online survey was distributed to these children and their parents in May 2020. The questionnaire collected information on the daily use of electronic devices and on the number of hours per week spent in activities regarding nonsport activities, highlighting the differences between those who interrupted sports and those who continued driven remotely by their instructors during the lockdown. Results: A total of 26 players continued practicing sports during the COVID-19 quarantine, while 18 players suspended their sports. Daily time spent on electronic devices increased significantly in both groups during the pandemic (p < .0001), regardless of whether they continued to practice sports (p > .05). On the other hand, in the group of children who interrupted sports, the time spent on activities regarding nonsport physical activity significantly changed during pandemic, with a 50% decrease (p = .0027) of those who spent more than 3 hr per week before the quarantine in favor of those who spent less than 3 hr per week. Conclusion: Quarantine increases screen time, which is a sedentary behavior that represents a risk factor for the health of children. Maintaining regular physical activity during quarantine due to COVID-19 was important to preserve some aspects of a healthy lifestyle in children, such as physical activity regardless of sport. While reducing physical activity and adapting it remotely, it is desirable that it be encouraged by experienced instructors in order to limit potential physical and psychological harm to children.
Dana Vander Wal, Brenda Potter, Shannon L. David, and Nicole German
Ulnar collateral ligament (UCL) injuries have become increasingly more common over the years. Reconstruction and nonoperative treatment have been the conventional treatment for athletes, especially for overhead athletes. This case study presents a 16-year-old female, competitive Level 10 gymnast, with a complete distal tear of her UCL with a full thickness, Grade 3, ulnar sided avulsion off of the sublime tubercle. She underwent medial UCL repair with internal brace augmentation with the goal of faster return to gymnastics. To the author’s knowledge, this is the second gymnast reported in the literature to have an internal brace augmentation completed on the UCL.
Katelyn M. Christian and Matthew F. Moran
The upper quarter Y-balance test is an upper extremity, closed kinetic chain assessment that requires individuals to reach in three directions while in a three-point plank position. The upper quarter Y-balance test was performed in 22 collegiate softball players (19.95 ± 1.52 years) to determine the (a) differences between throwing and nonthrowing (NT) sides and (b) influence of reach sequence. While stabilizing on the NT side, participants reached significantly further in the inferolateral direction than the throwing side (NT: 83.7 ± 12.2% arm length; throwing: 80.1 ± 10.5% arm length; p = .03; effect size = −0.57). Altering reach sequence significantly influenced medial reach (p < .01, effect size = 0.66) and composite score (p = .017, effect size = 1.03) when stabilizing on the NT side. Asymmetries in upper quarter Y-balance test in collegiate softball players should be interpreted cautiously, and an ordered test sequence should be consistently followed.
Kyle B. Kosik, Kathryn Lucas, Matthew C. Hoch, Jacob T. Hartzell, Katherine A. Bain, and Phillip A. Gribble
Studies have demonstrated that individuals with chronic ankle instability (CAI) have diminished dynamic stability. Jerk-based measures have been utilized to examine dynamic balance because of their ability to quantify changes in acceleration and may provide an understanding of the postural corrections that occur during stabilizing following a jumping task. The purpose of this study was to compare acceleration and jerk following a jump stabilization task between individuals with CAI and the uninjured controls. Thirty-nine participants volunteered to participate in this case control study. Participants completed a jump stabilization task requiring them to jump off 2 feet, touch a marker set at 50% of their maximal vertical jump height, land on a single limb, and maintain balance for 3 seconds. Acceleration was calculated as the second derivative, and jerk was calculated as the third derivative of the displacement of the resultant vector position. Participants with CAI had greater acceleration (mean difference = 55.6 cm/s2; 95% confidence interval, 10.3 to 100.90; P = .017) and jerk compared with the uninjured controls (mean difference = 1804.5 cm/s3; 95% confidence interval, 98.7 to 3510.3; P = .039). These results suggest that individuals with CAI made faster and more frequent active postural control corrections to regain balance following a jump compared with the uninjured controls.