This case study aims to discuss a proposal for identifying anterior cruciate ligament injury (ACL) risk by observing the variability of side cutting kinematics with respect to the development of fatigue. One participant (n=1) sustained an ACL injury while performing a side-cutting task during the latter stages of a soccer match a few months after a recorded laboratory session. Data from his laboratory session were then compared to matched samples of seventeen healthy, uninjured participants (n=17). The injured participant was found to have performed his side-cutting task with a lower deviation than mean variability before the later stages of the second half of simulated soccer match-play. Over time, the participant performed sidecutting tasks with increasing variability in sagittal plane kinematics, suggesting that compensatory actions may have been implemented to facilitate the task execution. This elevated variability may be indicative of an increased risk of ACL injury. Further prospective investigation is warranted to gain a deeper understanding of how variabilities may play a role in task execution performance with respect to injury mechanisms.
This study aimed to investigate the effects of a ball-oriented soccer match-play simulation on the hamstrings eccentric torque production. Seven male recreational athletes volunteered for this study. Participants completed 90- minutes of the ball-oriented soccer simulation interceded by a 15-minute half time interval with five successful trials of hamstrings eccentric contractions on an isokinetic dynamometer at selected time points throughout the simulation. A 2 (limb: dominant; non-dominant) × 4 (time: 0 min; 45 min; 60 min; 105 min) “split-plots” analysis of variance (SPANOVA) revealed significant reductions in hamstrings eccentric peak torques over time, while no significant change was apparent in hamstrings eccentric angles of peak torque. There was also no interaction effect of limb dominance over time for both peak torque and angles of peak torque parameters. The observed changes suggest that exertions from a ball-oriented soccer match-play simulation may have detrimental effects on the hamstrings eccentric strength parameters thus may increase risk of ACL injury. High variabilities in angles of peak torques were also observed in this study. Future exploration is warranted in order to address the extent of variabilities that may be present in larger sample sizes thus providing a better understanding of the influence of these variabilities on the muscular strength parameters of ACL injury risk. The findings suggest firstly, that fatigue from soccer-specific exertions during match-play may increase an athlete’s susceptibility to ACL injury, and secondly, that with accumulating fatigue, the nondominant limb may be equally at risk of injury as the dominant limb, contradicting previous findings from epidemiological studies.
Knee and hip extension are two proposed mechanisms of non-traumatic
anterior cruciate ligament (ACL) injury. This study aimed to investigate the
changes of the hip extension angles following exertion induced by an
overground simulated soccer match-play. Fifteen male recreational players
consented to this study and were required to complete a 90 minutes of
simulated soccer match-play. Knee and hip angles were measured at initial
contact during 45° anticipated side-cutting tasks performed prior to the
simulation (time 0 min), at the end of the first half (time 45 min) prior to the
second half (time 60 min) and at the end of the soccer match simulation (time
105 min). A two (group: dominant, nondominant) × four (time: 0 min, 45
min, 60 min and 105 min) mixed between- and within- subjects ANOVA was
utilized. Results revealed that both knee and hip extension angles were
significantly altered over time (knee: F3,102 = 4.464, p = 0.005, η2 = 0.116;
hip: F3,102 = 9.998, p = 0.000, η2 = 0.227), however no significant differences
were observed between dominant and nondominant sides (knee: F1,34 =
0.026, p = 0.872, η2 = 0.001; hip: F1,34 = 0.225, p = 0.638, η2 = 0.007).
Pairwise comparisons indicated that the knee and hip is more during the
second half of the simulation (time 60 min and time 105 min), compared to
pre-exertion (time 0 min) (p < 0.05). The more erect knee and hip landing
postures observed suggested a greater risk of ACL injury during the latter
stage of each halves of match-play, supporting epidemiological observations.
Further interrogations of the kinematic differences in the knees and hips
across limb dominance are warranted for a more comprehensive
understanding of the changes in a multiplanar perspective following soccer
specific fatigue development.