Changes in Lower Extremity Biomechanics Due to a Short-Term Fatigue Protocol

Abstract

Context: Noncontact anterior cruciate ligament injury has been reported to occur during the later stages of a game when fatigue is most likely present. Few researchers have focused on progressive changes in lower extremity biomechanics that occur throughout fatiguing.Objective: To evaluate the effects of a sequential fatigue protocol on lower extremity biomechanics during a sidestepcutting task (SS).Design: Controlled laboratory study. Setting: Laboratory.Patients or Other Participants: Eighteen uninjured female collegiate soccer players (age ¼ 19.2 6 0.9 years, height ¼ 1.66 6 0.5 m, mass ¼ 61.6 6 5.1 kg) volunteered.Intervention(s): The independent variable was fatigue level, with 3 levels (prefatigue, 50% fatigue, and 100% fatigue). Using 3-dimensional motion capture, we assessed lower extremity biomechanics during the SS. Participants alternated between a fatigue protocol that solicited different muscle groups and mimicked actual sport situations and unanticipated SS trials. The process was repeated until fatigue was attained.Main Outcome Measure(s): Dependent variables were hipand knee-flexion and abduction angles and internal moments measured at initial contact and peak stance and defined as measures obtained between 0% and 50% of stance phase.Results: Knee-flexion angle decreased from prefatigue (À178 6 58) to 50% fatigue (À168 6 68) and to 100% fatigue (À148 6 48) (F 2,34 ¼ 5.112, P ¼ .004). Knee flexion at peak stance increased from prefatigue (À52.98 6 5.68) to 50% fatigue (À56.18 6 7.28) but decreased from 50% to 100% fatigue (À50.58 6 7.18) (F 2,34 ¼ 8.282, P ¼ 001). Knee-adduction moment at peak stance increased from prefatigue (0.49 6 0.23 Nm/kgm) to 50% fatigue (0.55 6 0.25 Nm/kgm) but decreased from 50% to 100% fatigue (0.37 6 0.24) (F 2,34 ¼ 3.755, P ¼ 03). Hip-flexion angle increased from prefatigue (45.48 6 10.98) to 50% fatigue (46.28 6 11.28) but decreased from 50% to 100% fatigue (40.98 6 11.38) (F 2,34 ¼ 6.542, P ¼ .004). Hip flexion at peak stance increased from prefatigue (49.88 6 9.98) to 50% fatigue (52.98 6 12.18) but decreased from 50% to 100% fatigue (46.38 6 12.98) (F 2,34 ¼ 8.639, P ¼ 001). Hip-abduction angle at initial contact decreased from prefatigue (À13.88 6 6.68) to 50% fatigue (À9.18 6 6.58) and to 100% fatigue (À7.88 6 6.58) (F 2,34 ¼ 11.228, P , .001). Hip-adduction moment decreased from prefatigue (0.14 6 0.13 Nm/kgm) to 50% fatigue (0.08 6 0.13 Nm/kgm) and to 100% fatigue (0.06 6 0.05 Nm/kg) (F 2,34 ¼ 5.767, P ¼ .007).Conclusions: The detrimental effects of fatigue on sagittal and frontal mechanics of the hip and knee were visible at 50% of the participants' maximal fatigue and became more marked at 100% fatigue. Anterior cruciate ligament injury-prevention programs should emphasize feedback on proper mechanics throughout an entire practice and not only at the beginning of practice.Key Words: anterior cruciate ligament, knee, fatiguing, kinematics, kinetics Key PointsA progressive change in lower extremity mechanics occurred for knee-flexion angle, hip-abduction angle,...

Mapping current research trends on anterior cruciate ligament injury risk against the existing evidence: In vivo biomechanical risk factors

“…Fatigue has been observed to alter both the movement patterns and motor control [59,54,55]. Both males and females demonstrated reduced KAA moving closer 11 to neutral and decreased knee flexion at initial contact after fatiguing [59,54]. In addition, the KAM at peak stance and hip flexion angle was also decreased and a larger GRF was seen in females after fatigue [54,56].…”

“…Both males and females demonstrated reduced KAA moving closer 11 to neutral and decreased knee flexion at initial contact after fatiguing [59,54]. In addition, the KAM at peak stance and hip flexion angle was also decreased and a larger GRF was seen in females after fatigue [54,56]. Knee and hip control also altered neuromuscular characteristics [60,61].…”

“…Around 13% of the associative studies examined the effect of fatigue on ACL injury risk factors. Fatigue has been observed to alter both the movement patterns and motor control [59,54,55]. Both males and females demonstrated reduced KAA moving closer 11 to neutral and decreased knee flexion at initial contact after fatiguing [59,54].…”

“…DVJ tasks have been combined with the influence of fatigue [54][55][56][57][58] to examine the effect on biomechanical variables. Around 13% of the associative studies examined the effect of fatigue on ACL injury risk factors.…”

The effects of aerobic fatigue on jump shot kinematics in team handball players

“…The mechanisms causing these movements to be altered once a player reaches fatigue have yet to be examined, however, the effects of fatigue on both static and dynamic activities, focusing primarily on the lower extremity, have been extensively examined in other sports [2,3,[10][11][12][13][14][15][16] . While little research has aimed to examine kinematic differences in upper extremity movement patterns following fatigue, the literature available on the lower extremity has identified potential flawed mechanics that increase the risk of injury [2,3,[10][11][12][13][14][15][16] . For instance, movements that involve sudden change of direction, landing from a jump, and rapid stops are all non-contact mechanisms of injury that are greatly affected by lower extremity kinematics.…”