Effects of fatigue on biomechanical markers of ACL injury risk during jump-landing and single leg hop task / Siti Norfariza Mohd Noh

A higher prevalence of injuries occur during the latter stages of match-play may have
been attributed to match related fatigue. In the first part of the study, the purpose was
to determine the effect of high intensity short duration soccer-specific fatigue simulation
(SFP5
) on physiological changes in recreationally trained soccer players. Twenty (n =
20; age = 25 ± 4.9 years, height = 169 ± 6.6 cm, body mass = 70 ± 10.3 kg) male
recreational soccer players completed a 5 min high intensity soccer specific fatigue
simulation (SFP5
). Prior to simulation (time 0 min), immediately after simulation (time
5 min) and 15 min (time 20 min) post-simulation, participants performed three trials of
maximal counter movement jumps and subjective perceived exertions (RPE) were
recorded. Heart rate changes were recorded every 1 min throughout the fatigue
simulation. The heart rate and RPE were significantly increased at time 5 min (p<.001)
and was consistent with physiological responses during high intensity bouts of actual
match-play. Counter movement jumps performance significantly reduced at time 5 min
(p<.001), indicating the effect of fatigue during simulation. There were no significant
changes in heart rate, RPE and maximal counter movement jumps after 15 mins of
passive rest. The physiological responses observed during SFP5
are likely due to the
inclusion of soccer-specific ball handling utility movements and high accelerations and
deceleration, related with a short high intensity bout observed during soccer match-play.
In the second part of the study, the effect of short duration high intensity soccer-specific
fatigue simulation on jump-landing mechanics were investigated. In a single-group
repeated measures design, eighteen (n = 18) male recreationally trained soccer players
(age: 24 ± 4 years; body mass: 71 ± 10 kg; height, 169 ± 7 cm) completed a 5 min SFP5
.
Prior to simulation (time 0 min), immediately after simulation (time 5 min), and 15 min
(time 20 min) post-simulation, participants were tested for three trials of jump landing
task assessed using the Landing Error Scoring System (LESS) and single leg hop (SLH)
assessment. A significant increase in total LESS score (time 0 min: 3.6 ± 1.1; time 5
min: 4.8 ± 1.2; time 20 min: 4.4 ± 1.8) were observed over time (P < .001). Pairwise
comparison shown that LESS score at time 5 min (p = .001) and time 20 min (p = .001)
was significantly greater compared to time 0 min. No significant changes were observed
in knee extension angle. However, hip extension angle was significantly increase in
SLH (p = 0.037). Pairwise comparison revealed that the hip is more extended at time
20 min compared to time 5 min. These findings suggest a greater risk of ACL injury in
male players as a consequence of jump-landing impairments during fatigue. A 15
minutes of passive rest may also increase the risk of injury. Our findings support the
utilization of a short duration, high intensity soccer-specific fatigue simulation to
effectively identify markers of ACL injury risk in soccer players. It is recommended to
be include as part of preseason ACL injury risk screening and return to play assessment.