ABSTRACT
This study aimed to compare the effects of 8 weeks 11 + warm-up injury prevention program on kinematics and proprioception in adolescent male and female soccer players. Forty adolescent soccer players (20 males, 20 females) aged between 14-16 years old were randomly assigned into four groups. The experimental group performed the 11 + program for 8 weeks and the control group did their warm-up program. The kinematic variable in a cutting maneuver was measured using VICON motion analysis and ankle and knees' proprioception by joint position sense (JPS) was measured using a digital inclinometer. For kinematic variables only significant differences in knee valgus among females 11 + compared with female and male control groups were found (P < 0.05). Moreover, there were significant improvements in joint position sense variables in 11 + groups compared to control groups (P < 0.05). In conclusion, the 11 + program was proven to be a useful warm-up protocol in improving knee valgus and JPS among female and male adolescent soccer players. We suggest adding more training elements to the 11 + program that aimed to enhance the proper alignment of lower extremities which may consequently improve joint kinematics.
Subject(s)
Soccer , Warm-Up Exercise , Male , Humans , Adolescent , Female , Biomechanical Phenomena , Knee , Knee Joint , ProprioceptionABSTRACT
The purpose of the current study is to evaluate the effect of 4 weeks of home-based balance training (HBBT) on the performance of individuals with functional ankle instability (FAI) in daily activities and sports. Thirty college students diagnosed with FAI and with a mean weight of 79.8 ± 3.4 kg, height of 182.5 ± 5.1 cm, age of 23.5 ± 1.2 years, and instability score of 20 ± 2.3 were selected to participate in this study and were randomly divided by computer-generated methods into two groups: the HBBT group and the control group (CG), each consisting of 15 subjects. The HBBT group performed the program at home for 4 weeks, while the CG was non-exercise. Before and after the 4 weeks of exercise program, a form containing the foot and ankle ability measure for daily activities and sports was completed by the individuals. For data analysis, intra- and inter-group comparisons were performed using paired and independent sample t-tests, respectively, at a significance level of p ≤ 0.05. The results showed that 4 weeks of progressive HBBT were sufficient to significantly improve the measurement of the ability of ankle and foot function in individuals with FAI, even with a total volume of only 60 min per week. Accordingly, it is suggested that individuals with FAI can benefit from short-term HBBT programs, which are simple yet powerful enough to promote improvements in daily activities.
ABSTRACT
BACKGROUND: Rollover crashes of buses occur less frequently than do those involving passenger cars; however, they are associated with higher fatality rates. During rollover crashes, a vehicle experiences multidirectional acceleration and multiple impacts, yielding a complex interaction between structural components and its occupants. A better understanding of vehicle and occupant's motion, structural deformation, and vehicle and road interactions are necessary to improve the safety of the occupants during this event. One of the key factors in rollover crashworthiness assessment is to investigate the relationship between the strength of the vehicle's structure and the risk of injury outcomes. However, rollover crashes involving buses have received less research attention than have those involving passenger cars. Experimental studies in bus rollover safety have mainly focused on the structural integrity of the passenger compartment without considering the occupant responses. The main goal of this research is to evaluate the rollover mechanism and associated injury risk during two experimental rollover tests for a paratransit cutaway bus that is commonly used by transit agencies. METHODS: The modified dolly rollover (MDR) and tilt table (TT) tests were conducted using a similar bus and anthropomorphic test device (ATD) configurations. In each test, a 2-point and 3-point belted Hybrid III 50th percent male ATDs were used to quantify the kinematics of the occupants. The deformation index (DI), accelerations and angular velocities of the bus's CG were measured as vehicle responses. The collected data were then calibrated and filtered to assess the effects of the test procedure on kinematic responses of the vehicle and occupants. Next, the effectiveness of the 2-point vs 3-point seatbelt to reduce or prevent the injuries, the vulnerable body regions and corresponded injury risk were evaluated. RESULTS: The residual space remained intact (DIâ¯<â¯1) during both rollover tests, however, the ATD responses were quite different. The results of the injury assessment indicate that the risk of the injuries in the MDR test was significantly higher than the TT test. The highest risk of injuries was identified for the head, neck, and shoulder of 2-point belted ATD during the MDR test. Also, the main source of injuries during the MDR test was partial ejection due to the shattered side window, whereas for the TT test impacts between the ATDs and the side window and/or window frame were the injury causes. From the vehicle point of view, the total energy produced in the MDR was 3.5 times higher than the TT test, but the overall structural deformation in the TT test was higher than MDR test. Overall, the tilt table test provides a more severe scenario compared to the MDR test for the assessment of structural strength. Considering the limited real-world injury data in rollover crashes of buses, the MDR test presented the more realistic occupant responses.
