Anterior cruciate ligament (ACL) injury is common in sports that include 'change in direction' tasks. The aim of the current study was to determine the association between T2 relaxation time (an indicator of ACL integrity) of the distal portion of the ACL sub-region, biomechanical loading factors of the ACL, sex, and sport status of the participants. Participants between 18 to 35 years performed unanticipated 'change in direction' trials at their maximal self-preferred speed. The maximal knee flexion angle and the valgus moment of the right knee during the weight acceptance phase were analysed. MRI data (T2 relaxation time) of the ACL was also collected. Among the independent variables involved in the linear regression model, the association of the valgus moment and sex were statistically significant (p = 0.01 and p = 0.001 respectively). In conclusion, the main finding of the study is that higher T2 was significantly associated with a higher valgus moment as acute response to the 'change in direction' tasks. New sentence: In conclusion, the main finding of the study is that higher T2 was significantly associated with a higher valgus moment during 'change in direction' tasks.
- Klíčová slova
- Biomechanics, anterior cruciate ligament, loading, magnetic resonance imaging,
- Publikační typ
- časopisecké články MeSH
The lateral tilt of the arms accompanied by trunk lateral tilt is a typical blocking manoeuvre in volleyball. However, during this unanticipated blocking movement, an associated risk of ACL injury may result. The aim of the present study was to compare associative ACL risk factors at the initial contact and the first and second peak of VGRF during an unanticipated blocking movement with different arm positions. Synchronized kinematic and kinetic data were collected for each trial of each condition. Student paired t-tests and effect size were used to determine differences between two conditions (S - with arms straight up from the body) and (T - with the arms and trunk laterally tilted). The results showed that the T condition significantly decreases knee flexion, increases VGRF at the foot contact, first peak force and increases the valgus moment at the first peak force. The values of the associated risk factors for a non-contact ACL injury appear to be related to the tilted arm position accompanied by trunk tilt towards to right lower limb during landing. The players should be taught to land with greater knee flexion and, if possible, a double-leg landing to decrease right lower limb loading during the blocking manoeuvre.
- Klíčová slova
- Leg injuries, arms and trunk tilt, kinematics, kinetics, knee,
- MeSH
- biomechanika MeSH
- kinetika MeSH
- koleno fyziologie MeSH
- kondiční příprava fyziologie MeSH
- lidé MeSH
- mentoring MeSH
- mladiství MeSH
- motorické dovednosti fyziologie MeSH
- paže fyziologie MeSH
- pohyb fyziologie MeSH
- poranění předního zkříženého vazu patofyziologie MeSH
- rizikové faktory MeSH
- studie pohybu a času MeSH
- trup fyziologie MeSH
- volejbal fyziologie MeSH
- Check Tag
- lidé MeSH
- mladiství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
The number and type of landings performed after blocking during volleyball matches has been related to the potential risk of ACL injury. The aim of the present study was to determine whether gender affects the frequency of specific blocking landing techniques with potential risk of ACL injury from the perspective of foot contact and subsequent movement after the block used by volleyball players during competitive matches. Three matches involving four female volleyball teams (fourteen sets) and three matches involving four male volleyball teams (thirteen sets) in the Czech Republic were analyzed for this study. A Pearson chi-square test of independence was used to detect the relationship between gender and different blocking techniques. The results of the present study showed that gender affected single-leg landings with subsequent movement in lateral direction and double-leg landings. Although the total number of landings was lower for male athletes than for female athletes, a larger portion of male athletes demonstrated single leg landings with a subsequent movement than female athletes. Single leg landings with a subsequent movement have a higher potential risk of ACL injury.
- Klíčová slova
- ACL, Biomechanics, injury prevention, landing, volleyball,
- MeSH
- bérec fyziologie MeSH
- biomechanika MeSH
- kompetitivní chování fyziologie MeSH
- lidé MeSH
- motorické dovednosti fyziologie MeSH
- noha (od hlezna dolů) fyziologie MeSH
- pohyb fyziologie MeSH
- poranění předního zkříženého vazu patofyziologie prevence a kontrola MeSH
- rizikové faktory MeSH
- sexuální faktory MeSH
- studie pohybu a času MeSH
- videozáznam MeSH
- volejbal zranění fyziologie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Landing with a low knee flexion angle after volleyball block jumps may be associated with an increased risk of anterior cruciate ligament (ACL) injury. The aim of the present study was to identify the types of volleyball landings after blocks where the knee flexion angle is found to be under a critical knee flexion angle value of 30° at the instant of the first peak of the ground reaction force (GRF). Synchronized kinematic and kinetic data were collected for each trial. T-tests were used to determine if each knee flexion angle at the instant of the peak GRF was significantly different from the critical value of 30°. A repeated measures ANOVA was used to compare knee flexion angle, time to first peak and the magnitude of the first peak of the resultant GRF and knee stiffness. Significantly lower knee flexion angles were found in the "go" landing (p = .01, ES = 0.6) and the "reverse" landing (p = .02, ES = 0.6) only. The results for knee flexion angle and GRF parameters indicated a significant difference between a "reverse" and "go" and other types of landings, except the "side stick" landing for GRF. The "reverse" and "go" landings may present a risk for ACL injury due to the single-leg landing of these activities that have an associated mediolateral movement.
- Klíčová slova
- Leg injuries, kinematics, kinetics, knee, prevention,
- MeSH
- biomechanika fyziologie MeSH
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- poranění kolena epidemiologie patofyziologie MeSH
- sportovní úrazy epidemiologie patofyziologie MeSH
- sportovní výkon statistika a číselné údaje MeSH
- volejbal fyziologie statistika a číselné údaje MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
OBJECTIVES: To compare lower extremity mechanics and energy absorption during two types of landing after a successful or unsuccessful block in volleyball and assess the risks of anterior cruciate ligament (ACL) injury. DESIGN: Cohort study. SUBJECTS: Fourteen elite male volleyball players (aged 24.5 ± 4.6 years; height 1.94 ± 0.06 m; mass 86.6 ± 7.6 kg). INTERVENTIONS: Subjects were required to land on force platforms using stick landing or step-back landing (with the right lower extremity stepping back away from the net) techniques after performing a standing block jump movement. MAIN OUTCOME MEASURES: Vertical ground reaction force (body weight); knee flexion (degrees); knee moments (Nm/kg); and hip, knee and ankle energy absorption (J/kg). RESULTS: The right lower extremity showed a greater first peak of vertical ground reaction force, a greater valgus moment, lower energy absorption by the knee, and higher energy absorption by the hip and ankle joints during step-back landing. CONCLUSIONS: The lower extremity may be exposed to a greater risk of ACL injury when stepping back from the net during the initial impact phase after a step-back landing.
- Klíčová slova
- Injury prevention, Knee, Landing, Lower extremity,
- MeSH
- biomechanika MeSH
- dolní končetina * MeSH
- dospělí MeSH
- kohortové studie MeSH
- lidé MeSH
- mladý dospělý MeSH
- poranění předního zkříženého vazu * MeSH
- postura těla * MeSH
- rány a poranění etiologie MeSH
- rizikové faktory MeSH
- volejbal * MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A non-contact anterior cruciate ligament (ACL) injury is both a serious and very common problem in volleyball. The aim of the study was to determine the association between stick, step-back, and run-back landings after a block and select risk factors of ACL injuries for female professional volleyball players. The research sample involved fourteen female professional volleyball players. Two force plates were used to determine ground reaction forces. Eight infrared cameras were employed to collect the kinematic data. The one-factor repeated-measures analysis of variance, where the landing type was the factor, was used for comparing the valgus moment and ground reaction force on the right lower limb. ANOVA showed that the type of landing has a main effect on the valgus moment on the right lower limb (F) = 5.96, p = 0.019df = 1.18, partial η(2) = 0.239 and SP = 0.693). Furthermore, it did not show a main effect on the vertical reaction force on the right lower limb ((F)=2.77, p=0.090, df=1.55, partial η(2)= 0.128 and SP=0.448). The highest valgus moment occurred during the run-back landing. This moment, however, did not have any effect within the first 100 ms after initial contact with the ground, but rather upon the subsequent motion carried out when stepping back off the net. A comparison between a run-back landing and a step-back landing showed relevant higher values of vertical ground reaction forces during the run-back landing.
- Klíčová slova
- anterior cruciate ligament, injury prevention, kinetics,
- Publikační typ
- časopisecké články MeSH
