Kinetics of the lower extremities during drop landings from three heights

McNitt-Gray, Jill L.

doi:10.1016/s0021-9290(05)80003-x

Cited by 287 publications

(217 citation statements)

References 8 publications

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“…21 We instructed participants to step off the platform with the right leg extended while minimizing vertical displacement ( Figure 2) and to perform a double-leg landing with only the right foot making contact with the force plate. 3 The second task (flexed landing) was identical to the preferred-landing task, except that we instructed participants to actively flex the trunk during landing. Five trials were conducted for each task.…”

Section: Methodsmentioning

confidence: 99%

“…1,2 Upon ground contact, the knee is subjected to an external flexion moment produced by vertical and posterior ground reaction forces and downward acceleration of the mass proximal to the knee ( Figure 1). These landing forces have been reported in excess of 10 times the body weight 3 and have received considerable attention for their potential influence on ACL injuries. In a prospective investigation by Hewett et al, 4 individuals who sustained ACL injuries produced landing forces that were 20% greater than those who did not incur injury.…”

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confidence: 99%

“…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. 15 External knee flexion moment increases as a function of greater landing forces, 3 thus requiring a proportional increase in quadriceps force to provide adequate countermoment. Therefore, lower ground reaction forces are likely associated with a lower quadriceps force requirement, potentially reducing the force imparted to the ACL.…”

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

Blackburn

Padua

2009

Journal of Athletic Training

203

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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Section: Methodsmentioning

confidence: 99%

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

Blackburn

Padua

2009

Journal of Athletic Training

203

151

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“…To absorb the ground reaction force generated by the ground during drop-landing, plantar flexion and dorsiflexion are performed in the ankle joint 33) , and ankle joint movements are used more than hip joint movements to absorb shock 13) . Further, Tabrizi et al 34) reported that the rate of ankle injury can increase if the movements of the ankle joints decrease during drop-landing.…”

Section: Discussionmentioning

confidence: 99%

“…Generally, the maximum vertical reaction force during drop-landing is proportional to the height and speed of the drop-landing. McNitt-Gray 13) reported that the maximum vertical reaction force was larger when the height of the drop-landing was higher. According to Stürmer et al 14) , obese people possessed a larger maximum vertical reaction force than people with a normal weight.…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Loading Rate and Lower Limb Angles on Drop-landing between a Normal Foot and Flatfoot

Choi

Yoo

2012

J Phys Ther Sci

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Abstract.[Purpose] The purpose of this study was to analyze lower limb angles and the loading rate during the drop-landing motion of a normal foot and flatfoot and ultimately to offer basic data for flatfoot exercise therapy.[Subjects] For this study, 18 adults from Cheonan with no musculoskeletal lesions were collected as a sample. The sample was divided into normal foot (n=9) and flatfoot (n=9) groups. Each group performed a drop-landing motion on a force plate with markers attached to the anterior superior iliac spine, the greater trochanter of the hip, the lateral epicondyle of the knee, the lateral malleolus, and the fifth metatarsal head. The motion was measured in 3D. The data for the angle of the hip joint, knee joint, and ankle joint during the drop-landing motion and the loading rate and maximum vertical reaction force at the force plate were measured.[Results] There were significant differences in the maximum vertical reaction force and loading rate during the drop-landing motion between the normal foot and flatfoot. There was a significant difference in the right ankle joint in terms of the variation in the lower limb angles.[Conclusion] It was difficult for the flatfoot to disperse the loading rate during the drop-landing motion, and it showed an increase in the lower limb bending angle. It was considered that proper pose control for the absorption of loads and strengthening of the lower limb were definitely needed for a flatfoot.

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Prospective Study of Physical Activity and Risk of Developing a Stress Fracture Among Preadolescent and Adolescent Girls

Field

Gordon²,

Pierce³

et al. 2011

Arch Pediatr Adolesc Med

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The adolescent girls' history of stress fracture, including age when fracture occurred and site, were reported by their mothers, who are registered nurses, in 2004. Cox proportional hazards models were used in the analysis.Main Outcome Measure: Incident stress fracture that occurred between 1997 and 2004.Results: During 7 years of follow-up, 267 girls (3.9%) developed a stress fracture. Independent of age, age at menarche, family history of fracture, and hours per week of low-and moderate-impact activity, hours per week of running (hazard ratio = 1.13; 95% confidence interval, 1.04-1.23), basketball (hazard ratio = 1.12; 95% confidence interval, 1.03-1.23), and cheerleading/ gymnastics (hazard ratio = 1.12; 95% confidence interval, 1.02-1.22) were significant predictors of developing a stress fracture. No other type of high-impact activity was associated with an increased risk. Conclusion:Girls who engage in running, basketball, cheerleading, or gymnastics should be encouraged to include varied training in lower-impact activities to decrease the cumulative amount of impact in order to minimize their risk of stress fractures.

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Kinetics of the lower extremities during drop landings from three heights

Cited by 287 publications

References 8 publications

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

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

Comparison of the Loading Rate and Lower Limb Angles on Drop-landing between a Normal Foot and Flatfoot

Prospective Study of Physical Activity and Risk of Developing a Stress Fracture Among Preadolescent and Adolescent Girls

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