Effects of a Knee Ligament Injury Prevention Exercise Program on Impact Forces in Women

Irmischer, Bobbie S.; Harris, Chad; Pfeiffer, Ronald P.; DeBeliso, Mark; Adams, Kent J.; Shea, Kevin G.

doi:10.1519/00124278-200411000-00003

Cited by 11 publications

(11 citation statements)

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“…Although many knee ligament injury prevention training programs have been published, [66][67][68][69][70][71][72][73][74][75][76][77][78][79][80] few have presented scientifi c justifi cation that the training eff ectively improved neuromuscular defi ciencies and reduced the incidence of noncontact ACL injuries in female athletes (Table 3). Some programs had either small sample sizes or few noncontact ACL injuries [69][70][71]75,77,78,80 and were thus underpowered to avoid the potential for a type II statistical error.…”

Section: Neuromuscular Retraining Programs To Decrease the Risk Of Nomentioning

confidence: 99%

Reducing the Risk of Noncontact Anterior Cruciate Ligament Injuries in the Female Athlete

Barber-Westin

Noyes

Smith

et al. 2009

The Physician and Sportsmedicine

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High school and collegiate female athletes have a significantly increased risk of sustaining a noncontact anterior cruciate ligament injury compared with male athletes participating in the same sport. This review summarizes the current knowledge of the risk factors hypothesized to influence this problem, and the neuromuscular training programs designed to correct certain biomechanical problems noted in female athletes. The risk factors include a genetic predisposition for sustaining a knee ligament injury, environmental factors, anatomical indices, hormonal influences, and neuromuscular factors. The greatest amount of research in this area has studied differences between female and male athletes in movement patterns during athletic tasks; muscle strength, activation, and recruitment patterns; and knee joint stiffness under controlled, preplanned, and reactive conditions in the laboratory. Neuromuscular retraining programs have been developed in an attempt to reduce these differences. The successful programs teach athletes to control the upper body, trunk, and lower body position; lower the center of gravity by increasing hip and knee flexion during activities; and develop muscular strength and techniques to land with decreased ground reaction forces. In addition, athletes are taught to preposition the body and lower extremity prior to initial ground contact to obtain the position of greatest knee joint stability and stiffness. Two published programs have significantly reduced the incidence of noncontact anterior cruciate ligament injuries in female athletes participating in basketball, soccer, and volleyball. Other programs were ineffective, had a poor study design, or had an insufficient number of participants, which precluded a true reduction in the risk of this injury. In order to determine which risk factors for noncontact anterior cruciate ligament ruptures are significant, future investigations should include larger cohorts of athletes in multiple sports, analyze factors from all of the major risk categories, and follow athletes for at least one full athletic season. Future risk assessment studies should incorporate reactive tasks under more realistic sports conditions.

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Section: Neuromuscular Retraining Programs To Decrease the Risk Of Nomentioning

confidence: 99%

Reducing the Risk of Noncontact Anterior Cruciate Ligament Injuries in the Female Athlete

Barber-Westin

Noyes

Smith

et al. 2009

The Physician and Sportsmedicine

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“…6,7,[18][19][20] Therefore, programs designed to improve strength and balance and to instruct athletes in proper lower extremity alignment during jump-landing activities often are used to decrease the risk of ACL injury. [21][22][23][24][25] These injury-prevention programs have succeeded in demonstrating that an athlete's biomechanics can be altered. The focus of most prevention programs, whether they are based on plyometrics, balance, or instruction, is on improving landing or decelerating technique and incorporates oral and visual feedback.…”

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confidence: 99%

Instruction and Jump-Landing Kinematics in College-Aged Female Athletes Over Time

Etnoyer

Cortés

Ringleb

et al. 2013

Journal of Athletic Training

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Context: Instruction can be used to alter the biomechanical movement patterns associated with anterior cruciate ligament (ACL) injuries.Objective: To determine the effects of instruction through combination (self and expert) feedback or self-feedback on lower extremity kinematics during the box-drop-jump task, running-stop-jump task, and sidestep-cutting maneuver over time in college-aged female athletes.Design: Randomized controlled clinical trial. Setting: Laboratory.Patients or Other Participants: Forty-three physically active women (age ¼ 21.47 6 1.55 years, height ¼ 1.65 6 0.08 m, mass ¼ 63.78 6 12.00 kg) with no history of ACL or lower extremity injuries or surgery in the 2 months before the study were assigned randomly to 3 groups: self-feedback (SE), combination feedback (CB), or control (CT).Intervention(s): Participants performed a box-drop-jump task for the pretest and then received feedback about their landing mechanics. After the intervention, they performed an immediate posttest of the box-drop-jump task and a runningstop-jump transfer test. Participants returned 1 month later for a retention test of each task and a sidestep-cutting maneuver. Kinematic data were collected with an 8-camera system sampled at 500 Hz. Main Outcome Measure(s):The independent variables were feedback group (3), test time (3), and task (3). The dependent variables were knee-and hip-flexion, knee-valgus, and hip-abduction kinematics at initial contact and at peak knee flexion.Results: For the box-drop-jump task, knee-and hip-flexion angles at initial contact were greater at the posttest than at the retention test (P , .001). At peak knee flexion, hip flexion was greater at the posttest than at the pretest (P ¼ .003) and was greater at the retention test than at the pretest (P ¼ .04); knee valgus was greater at the retention test than at the pretest (P ¼ .03) and posttest (P ¼ .02). Peak knee flexion was greater for the CB than the SE group (P ¼ .03) during the box-drop-jump task at posttest. For the running-stop-jump task at the posttest, the CB group had greater peak knee flexion than the SE and CT (P .05).Conclusions: Our results suggest that feedback involving a combination of self-feedback and expert video feedback with oral instruction effectively improved lower extremity kinematics during jump-landing tasks.

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“…7,8 Based on this notion, numerous investigations and ACL injury-prevention programs have been implemented in an effort to reduce landing forces. [9][10][11] After initial ground contact during landing, the quadriceps act eccentrically to counter the knee flexion imposed by ground reaction forces. Research in the cadaveric knee 12,13 and in vivo 14 has indicated that quadriceps activation introduces stress and strain to the ACL and is capable of producing ACL injury and rupture in vitro.…”

mentioning

confidence: 99%

Sagittal-Plane Trunk Position, Landing Forces, and Quadriceps Electromyographic Activity

Blackburn

Padua

2009

Journal of Athletic Training

197

151

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Context: Researchers have suggested that large landing forces, excessive quadriceps activity, and an erect posture during landing are risk factors for anterior cruciate ligament (ACL) injury. The influence of knee kinematics on these risk factors has been investigated extensively, but trunk positioning has received little attention.Objective: To determine the effect of trunk flexion on landing forces and quadriceps activation during landing.Design: Two (sex) 3 2 (task) repeated-measures design. Intervention(s): Participants performed 2 drop-landing tasks. The first task represented the natural, or preferred, landing strategy. The second task was identical to the first except that participants flexed the trunk during landing.Main Outcome Measure(s): We measured peak vertical and posterior ground reaction forces and mean quadriceps electromyographic amplitude during the loading phase of landing (ie, the interval from initial ground contact to peak knee flexion).Results: Trunk flexion decreased the vertical ground reaction force (P , .001) and quadriceps electromyographic amplitude (P , .001). The effect of trunk flexion did not differ across sex for landing forces or quadriceps electromyographic activity.Conclusions: We found that trunk flexion during landing reduced landing forces and quadriceps activity, thus potentially reducing the force imparted to the ACL. Research has indicated that trunk flexion during landing also increases knee and hip flexion, resulting in a less erect landing posture. In combination, these findings support emphasis on trunk flexion during landing as part of ACL injury-prevention programs.Key Words: anterior cruciate ligament, ground reaction forces, injury prevention, risk factors Key Points N Trunk flexion during landing reduced landing forces and quadriceps activity. N The influence of trunk flexion on landing forces and quadriceps activity did not differ across sex. N Trunk flexion potentially reduces the quadriceps force requirement and subsequent load placed on the anterior cruciate ligament immediately after ground contact during landing.N Because of its influences on kinetic, kinematic, and neuromuscular risk factors for anterior cruciate ligament injury, active trunk flexion during landing might be an important component of injury-prevention programs.

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Effects of a Knee Ligament Injury Prevention Exercise Program on Impact Forces in Women

Cited by 11 publications

References 0 publications

Reducing the Risk of Noncontact Anterior Cruciate Ligament Injuries in the Female Athlete

Reducing the Risk of Noncontact Anterior Cruciate Ligament Injuries in the Female Athlete

Instruction and Jump-Landing Kinematics in College-Aged Female Athletes Over Time

Sagittal-Plane Trunk Position, Landing Forces, and Quadriceps Electromyographic Activity

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