Context: Excessive knee valgus on landing can cause anterior cruciate ligament injury. Therefore, knee valgus alignment may show characteristic energy absorption patterns during landings with lateral movement that impose greater impact forces on the knee joint compared with landings in other alignments. Objective: To investigate the energy absorption strategy in lower-extremities during side steps in females with knee valgus alignment. Design: Controlled laboratory study. Setting: University research laboratory. Participants: A total of 34 female college students participated in this experiment. Interventions: Participants performed single-leg drop vertical jump and side steps. All participants were divided into valgus (n = 13), neutral (n = 9), and varus (n = 12) groups according to knee position during landing in single-leg drop vertical jumps. Main Outcome Measures: Lower-extremity joint angles, moments, and negative works were calculated during landing in side steps, and 1-way analysis of variance and post hoc tests were used to determine between-group differences. Results: Negative works of hip extensors, knee abductors, and ankle plantar flexors during landing in side steps were significantly smaller in the valgus than in the varus group; however, negative work of the knee extensors was significantly greater in the valgus group than in varus group. Conclusions: The findings of this study indicated that landing with knee valgus induced the characteristic energy absorption strategy in the lower-extremity. Knee extensors contributed more to energy absorption when landing in knee valgus than in knee varus alignment. Learning to land in knee varus alignment might reduce the impact on the knee joint by increasing the energy absorption capacities of hip extensors, knee abductors, and ankle plantar flexors.
Akihiro Tamura, Kiyokazu Akasaka and Takahiro Otsudo
Jeannine Ohlert, Thea Rau and Marc Allroggen
accompanied by other forms of interpersonal violence, especially emotional violence ( Vertommen et al., 2016 ). This finding is important for the development of preventive measures, as these should target not only sexual violence, but all kinds of interpersonal violence. From our point of view, the most
Mattias Eckerman, Kjell Svensson, Gunnar Edman and Marie Alricsson
subsequently allow for preventive measures, both physiological and psychological. The purpose of the present study was to investigate whether personality traits affect the incidence of muscle injuries among male football players from the first league in Sweden. Our hypothesis was there is a difference in
Nicholas H. Yang, Paul K. Canavan and Hamid Nayeb-Hashemi
Subject-specific models were developed and finite element analysis was performed to observe the effect of the frontal plane tibiofemoral angle on the normal stress, Tresca shear stress and normal strain at the surface of the knee cartilage. Finite element models were created for three subjects with different tibiofemoral angle and physiological loading conditions were defined from motion analysis and muscle force mathematical models to simulate static single-leg stance. The results showed that the greatest magnitude of the normal stress, Tresca shear stress and normal strain at the medial compartment was for the varus aligned individual. Considering the lateral knee compartment, the individual with valgus alignment had the largest stress and strain at the cartilage. The present investigation is the first known attempt to analyze the effects of tibiofemoral alignment during single-leg support on the contact variables of the cartilage at the knee joint. The method could be potentially used to help identify individuals most susceptible to osteoarthritis and to prescribe preventive measures.
Heidi R. Thornton, Jace A. Delaney, Grant M. Duthie, Brendan R. Scott, William J. Chivers, Colin E. Sanctuary and Ben J. Dascombe
To identify contributing factors to the incidence of illness for professional team-sport athletes, using training load (TL), self-reported illness, and well-being data.
Thirty-two professional rugby league players (26.0 ± 4.8 y, 99.1 ± 9.6 kg, 1.84 ± 0.06 m) were recruited from the same club. Players participated in prescribed training and responded to a series of questionnaires to determine the presence of self-reported illness and markers of well-being. Internal TL was determined using the session rating of perceived exertion. These data were collected over 29 wk, across the preparatory and competition macrocycles.
The predictive models developed recognized increases in internal TL (strain values of >2282 AU, weekly TL >2786 AU, and monotony >0.78 AU) to best predict when athletes are at increased risk of self-reported illness. In addition, a reduction in overall well-being (<7.25 AU) in the presence of increased internal TL, as previously stated, was highlighted as a contributor to self-reported-illness occurrence.
These results indicate that self-report data can be successfully used to provide a novel understanding of the interactions between competition-associated stressors experienced by professional team-sport athletes and their susceptibility to illness. This may help coaching staff more effectively monitor players during the season and potentially implement preventive measures to reduce the likelihood of illnesses occurring.
Javad Sarvestan and Zdeněk Svoboda
Background: Taping is a preventive measure commonly used for protecting and strengthening the ankle joint to prevent further musculoskeletal damage. Ankle taping prevents excessive range of motion (ROM) of the ankle joint and allows the improvement of proprioception to adjust balance. Appropriate ankle stability is essential for various activities, such as sprinting, turning, cutting, and jumping, which are associated with agility. Aim: To assess the acute effect of Kinesio taping and athletic taping on the ankle ROM of athletes with chronic ankle sprain during various agility tests that include sprinting, turning, and cutting actions. Methods: Twenty-five physically active volunteers with chronic ankle sprain performed the Illinois, 5–0–5, 10-m shuttle, hexagon, compass drill, and T agility tests in 3 ankle conditions (nontaped, Kinesio taped, and athletic taped), in random order. Ankle ROM was recorded using the Vicon motion capture system. Results: In comparison with the nontaped ankle condition, in the ankle Kinesio-taping condition, the results showed a significant increase of ankle ROM in the sprinting part of the Illinois, 5–0–5, 10-m shuttle, and T agility tests (P ≤ .01), whereas in the ankle athletic-taping condition, no significant difference was found in ankle ROM during all agility tests. Conclusion: In sports that need linear sprinting, Kinesio taping seems to be a suitable intervention for the improvement of sports performance as it provides increased ankle ROM.
Ghada Jouira, Selim Srihi, Fatma Ben Waer, Haithem Rebai and Sonia Sahli
Context: Athletes with intellectual disability (ID) have a high risk of injury while participating in various sports. Warm-up (WU) is the most preventive measure to reduce injuries in sports. Objective: To investigate the effects of dynamic stretching WU (DS-WU) and plyometric WU (PL-WU) on dynamic balance in athletes with ID. Design: Crossover study. Setting: Research laboratory. Participants: A total of 12 athletes with ID (age 24.5 [3.22] y, height 165.7 [8.4] cm, weight 61.5 [7.1] kg, intelligence quotient 61.1 [3.5]). Main Outcome Measures: Dynamic balance was assessed using the Star Excursion Balance Test (SEBT) at pre-WU, post-WU, and 15 minutes post-WU for both the DS-WU and the PL-WU. A 2-way analysis of variance (3 sessions × 2 WU methods) with repeated-measures was used in this study. Results: Following the DS-WU, participants demonstrated significant improvements in the SEBT composite score post-WU (89.12% [5.54%] vs 87.04% [5.35%]; P < .01) and at 15 minutes post-WU (89.55% [5.28%] vs 87.04%, P < .01) compared with pre-WU. However, no significant difference between these two post-WU scores (post-WU and 15 min post-WU) was found. For the PL-WU, participants demonstrated a significant decrease in the SEBT composite score at post-WU (85.95% [5.49%] vs 87.02% [5.73%]; P < .05); however, these scores increased significantly at 15 minutes post-WU (88.60% [5.42%] vs 87.02% [5.49%]; P < .05) compared with that at pre-WU. The SEBT composite scores are significantly higher in the DS-WU than in the PL-WU at both post-WU sessions (P < .05). Conclusion: Both DS-WU and PL-WU could improve dynamic balance and may be recommended as WUs in athletes with ID; however, particular caution should be exercised immediately after the PL-WU.
Zachary Y. Kerr, Susan W. Yeargin, Yuri Hosokawa, Rebecca M. Hirschhorn, Lauren A. Pierpoint and Douglas J. Casa
preventable with appropriate treatment, 1 preventive measures must be developed to minimize the incidence, severity, and outcomes of such injuries. The van Mechelen et al 8 sequence of injury prevention has emphasized injury prevention benefits from ongoing monitoring of injury incidence, particularly to
Pilar Lavielle Sotomayor, Gerardo Huitron Bravo, Analí López Fernández and Juan Talavera Piña
prioritized preventive measure for public health. 4 Health service activities should be reoriented toward health promotion and must involve physicians in the prescription of PA. 5 , 6 They have frequent contact with a large percentage of the population and are a respected source of information for patients
Grégoire P. Millet and Kilian Jornet
preacclimatization (ie, spending time in hypoxia before ascending to the target altitude, described as “staged ascent”) 1 are generally recommended as effective preventive measures, by increasing the positive adaptations and/or decreasing the prevalence and severity of acute altitude illness. Regarding the speed of