scholarly journals The Effects of the Functional Garment on the Biomechanics During the Single Leg Drop Landing.

Author(s):  
Shintarou Kudo ◽  
Ayane Yamamoto ◽  
Sho Katayama ◽  
Toshinori Miyashita ◽  
Raita Takasaki

Abstract Background: Female athletes with an anterior cruciate ligament (ACL) injury should decrease both dynamic valgus of the knee and related kinematics of the lower limb during single leg drop landing (SLDL). A functional biomechanics garment (FBG) may help prevent injury by improved kinematics during motion. The purpose of this study was to investigate the effects of the FBG on the biomechanics of SLDL.Methods: Seventeen female university basketball players participated in this study. Characteristics of the FBG were designed based on biomechanics during weight-loaded performance of human movement such as gait, running, and jumping. Lower limb kinematic and kinetic data were calculated using a three-dimensional motion analysis system during a SLDL task with and without the FBG. The hip, knee, and ankle angles and joint moments were automatically calculated from the standard plug-in gait lower body model. The average values of lower limb kinematics and kinetics in the sagittal and frontal planes from 3 SLDL with and without FBG were measured and compared.Results: The maximum varus angle of the knee showed a significant difference between with FBG (15.3±15.1 degrees) and without FBG (5.9±15.4 degrees). (p<0.01; effect size 0.6) Conclusion: Use of the FBG decreases dynamic knee valgus, which reduces risk of knee injury. The FBG can reduce dynamic knee valgus during SLDL in athletic rehabilitation and to play a role in the prevention of knee injury.

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Taylor Oldfather ◽  
Michael Zabala ◽  
Michael Goodlett ◽  
William (Hank) Murrah

Abstract The knee valgus angle (KVA) is heavily researched as it has been shown to correlate to anterior cruciate ligament (ACL) injuries when measured during jumping activities. Many different methods of KVA calculation are often treated as equivalent. The purpose of this study is to elucidate differences between these commonly used angles within and across activities to determine if they can indeed properly be treated as equivalent. The kinematics of 23 female athletes, D1 soccer, D1 basketball, and club soccer (height = 171.2 ± 88.9 cm, weight = 66.3 ± 8.6 kg, age = 19.8 ± 1.9 years), was analyzed using a motion capture system during activities related to their sport and daily living. The abduction KVA, measured using body fixed axes, only correlated to the two-dimensional (2D) global reference frame angle (KVA 2G) in three of the six activities (walking, squatting, and walking down stairs), and one out of six in the three-dimensional (3D) measurements (jogging). This suggests that the abduction KVA does not always relate to other versions of KVA. The KVA with reference to the pelvis coordinate system (KVA 2P) correlated to the KVA 2G in six out of six activities (r = 0.734  ±  0.037, P &lt;&lt; 0.001) suggesting the pelvis can be utilized as a reference plane during rotating tasks, such as run-to-cut, when a fixed global system is less meaningful. Not all measures of KVA are equivalent and should be considered individually. A thorough understanding of the equivalence or nonequivalence of various measures of KVA is essential in understanding ACL injury risk.


2019 ◽  
Vol 41 (02) ◽  
pp. 113-118
Author(s):  
Gabrielle Gilmer ◽  
Gretchen D. Oliver

AbstractRecently, an emphasis has been placed on understanding how ovarian sex hormones and hormonal contraceptives affect risk for anterior cruciate ligament (ACL) injury. The literature presents large discrepancies in whether or not hormonal contraceptives affect ACL injury risk; therefore, the purpose of this study was to evaluate whether vertical ground reaction force (GRF) and knee valgus force are different between athletes who do and do not use hormonal contraceptives. Twenty-two female athletes volunteered to participate and were divided into two groups based on their answers to a health history questionnaire: those who use hormonal contraceptives and those who do not. Participants performed a drop vertical jump (DVJ) and single leg crossover dropdown (SCD) at two different time points in their menstrual cycle (pre-ovulatory phase and mid-luteal phase). Kinetic data were collected at 1000 Hz. Independent samples t-tests revealed no significant differences between groups in vertical GRF and knee valgus force at both time points. Findings from this study suggest that hormonal contraceptives do not elicit detectable changes in vertical GRF and knee valgus force. Ultimately, this calls for further studies on the relationship between hormones and ACL injury risk and physicians to consider hormonal screening in addition to neuromuscular and biomechanical screening.


2007 ◽  
Vol 35 (9) ◽  
pp. 1528-1536 ◽  
Author(s):  
Rajiv Kaila

Background The influence of modern studded and bladed soccer boots and sidestep cutting on noncontact knee loading during match play conditions is not fully understood. Hypothesis Modern soccer boot type and sidestep cutting compared with straight-ahead running do not significantly influence knee internal tibia axial and valgus moments, anterior joint forces, and flexion angles. Study Design Controlled laboratory study. Methods Fifteen professional male outfield soccer players undertook trials of straight-ahead running and sidestep cutting at 30° and 60° with a controlled approach velocity on a Fédération Internationale de Football Association (FIFA) approved soccer surface. Two bladed and 2 studded soccer boots from 2 manufacturers were investigated. Three-dimensional inverse dynamics analysis determined externally applied internal/external tibia axial and valgus/varus moments, anterior forces, and flexion angles throughout stance. Results The soccer boot type imparted no significant difference on knee loading for each maneuver. Internal tibia and valgus moments were significantly greater for sidestep cutting at 30° and 60° compared with straight-ahead running. Sidestep cutting at 60° compared with straight-ahead running significantly increased anterior joint forces. Conclusion Varying soccer boot type had no effect on knee loading for each maneuver, but sidestep cutting significantly increased internal tibia and valgus moments and anterior joint forces. Clinical Relevance Sidestep cutting, irrespective of the modern soccer boot type worn, may be implicated in the high incidence of noncontact soccer anterior cruciate ligament injuries by significantly altering knee loading.


2007 ◽  
Vol 36 (2) ◽  
pp. 285-289 ◽  
Author(s):  
Michael Joseph ◽  
David Tiberio ◽  
Jennifer L. Baird ◽  
Thomas H. Trojian ◽  
Jeffrey M. Anderson ◽  
...  

Background Female athletes land from a jump with greater knee valgus and ankle pronation/eversion. Excessive valgus and pronation have been linked to risk of anterior cruciate ligament injury. A medially posted orthosis decreases component motions of knee valgus such as foot pronation/eversion and tibial internal rotation. Hypothesis We hypothesized a medial post would decrease knee valgus and ankle pronation/eversion during drop-jump landings in NCAA-I female athletes. Study Design Controlled laboratory study. Methods Knee and ankle 3-dimensional kinematics were measured using high-speed motion capture in 10 National Collegiate Athletic Association Division I female athletes during a drop-jump landing with and without a medial post. Analysis of variance was used to determine differences in posting condition, t tests were used to determine dominant-nondominant differences, and the Pearson correlation coefficient was used to determine relationships between variables. Results Significant differences were found for all measures in the posted condition. A medial post decreased knee valgus at initial contact (1.24°, P< .01) and maximum angle (1.21 °, P< .01). The post also decreased ankle pronation/eversion at initial contact (0.77°, P < .01) and maximum angle (0.95°, P = .039). Conclusion The authors have demonstrated a significant decrease in knee valgus and ankle pronation/eversion during a drop jump with a medial post placed in the athletes’ shoes. Clinical Relevance A medial post may be a potential means to decrease risk of anterior cruciate ligament injury.


2020 ◽  
Author(s):  
Azadeh Nasseri ◽  
David G Lloyd ◽  
Adam L Bryant ◽  
Jonathon Headrick ◽  
Timothy Sayer ◽  
...  

AbstractThis study determined anterior cruciate ligament (ACL) force and its contributors during a standardized drop-land-lateral jump task using a validated computational model. Healthy females (n=24) who were recreationally active performed drop-land-lateral jump and straight run tasks. Three-dimensional whole-body kinematics, ground reaction forces, and muscle activation patterns from eight lower limb muscles were collected concurrently during both tasks, but only the jump was analyzed computationally, with the run included for model calibration. External biomechanics, muscle-tendon unit kinematics, and muscle activation patterns were used to model lower limb muscle and ACL forces. Peak ACL force (2.3±0.5 BW) was observed at 13% of the stance phase during the drop-land-lateral jump task. The ACL force was primarily developed through the sagittal plane, and muscle was the dominant source of ACL loading. The gastrocnemii and quadriceps were main ACL antagonists (i.e., loaders), while hamstrings were the main ACL agonists (i.e., supporters).


2020 ◽  
Vol 41 (03) ◽  
pp. 182-188
Author(s):  
Gabrielle G. Gilmer ◽  
Michael D. Roberts ◽  
Gretchen D. Oliver

AbstractFemale athletes are at an elevated risk for tearing their anterior cruciate ligament, compared to their male counterparts. Though injury screening clinical tests and neuromuscular training programs have been widely implemented, injury rates remain high among female athletes. The purpose of this study was to examine the relationship between serum relaxin concentrations and knee valgus during three clinical tests (single leg squat, drop vertical jump, and single leg crossover dropdown). Twenty-two female athletes volunteered. Participants were scheduled for collection during the mid-luteal phase, when serum relaxin concentrations are known to be measurable. Blood samples were collected, and serum relaxin concentrations were quantified. Kinematic data were collected while participants performed the three clinical tests. Regression analyses revealed statistically significant relationships between serum relaxin concentrations and knee valgus throughout all tests. These findings suggest that serum relaxin concentrations and knee valgus are not independent of each other and more holistic approaches may be necessary to truly map out the risk for injury and ultimately reduce the rate of anterior cruciate ligament injuries. Thus, concluding that knee valgus, a highly utilized modifiable biomechanical risk factor, and relaxin, a hormone that has been associated with anterior cruciate ligament injury in female athletes, are related to each other.


1999 ◽  
Author(s):  
Hongzhi Yang ◽  
Yi-Chun Li ◽  
Mohamed Samir Hefzy

Abstract The exercises to strengthen the muscles around the knee are designed to improve its stability. During these exercises, co-contraction of the hamstrings occur depending on the level of quadriceps contraction. The purpose of this study is to develop a three-dimensional knee model that includes tibia, femur and patella and allows to predict knee response due to quadriceps and hamstrings co-contractions. As an application, results quantifying the changes in knee response are obtained following a simulated posterior cruciate ligament (PCL) injury. This is motivated by the continuing debate whether surgical repair is the method of choice for individuals with such an injury. It has been reported that following a knee injury, a large number of patients with PCL deficiency develop significant disability with Osteoarthritis (OA). The conditions tested simulate the straight-leg-raise exercise, during which the quadriceps muscles contract isometrically along with hamstrings co-contractions.


2019 ◽  
Vol 7 (3_suppl) ◽  
pp. 2325967119S0008
Author(s):  
Aaron J. Zynda ◽  
Henry B. Ellis ◽  
Kirsten Tulchin-Francis ◽  
Anthony Anderson ◽  
Parker Mitchell ◽  
...  

Introduction: Peak external knee valgus moment can predict future ACL injury and is, often times, asymmetric following anatomic intra-articular ACL reconstruction. The purpose of this study is to evaluate the external knee valgus moment during a drop landing and a single limb squat 2 years following an iliotibial band (ITB) intra-articular and extra-articular physeal-sparing ACL reconstruction. Methods: Fourteen study subjects (mean age: 14.3 ± 2.6 yrs) who had previously undergone a physeal-sparing ACL reconstruction, as originally described by McIntosh using an ITB autograft, were enrolled in this IRB-approved study. All subjects were seen at a minimum of 24 months after surgery (mean follow-up: 55.0 ± 28.9 mos) and clinical, radiographic, and patient reported outcomes were collected. During functional testing, subjects underwent drop landing (DL) and unilateral squat (US) tasks. Isokinetic muscle strength of the hip and knee was collected using an isokinetic dynamometer at 60°/s. Paired student’s t-tests evaluated differences between affected (AFF) and unaffected (UNAFF) limbs. Results: During a drop landing, the AFF limb, compared to the UNAFF limb, did not demonstrate a difference in external knee valgus moment (0.50° vs. 0.51°, p=0.736). However, in the AFF limb, the mean knee peak knee valgus angle was 2.8 degrees less than the UNAFF limb during a drop landing (p=0.039). This difference was not considered within the range of a minimal clinical difference (MCD) of 5.1 degrees. Similar trends were found during a single limb squat with no significant difference seen in peak knee valgus moment between AFF and UNAFF (0.14° vs. 0.07°, p=0.150) with a statistical, yet not minimal clinical difference, in knee valgus angle at 45° squat position (-2.4° vs. 0.7°, p=0.033; MCD = 5.2). Thus, no asymmetry in peak knee valgus moment during a drop landing or a single limb squat following an ITB intra- and extra-articular ACL reconstruction was observed. In this series at 2 years’ post-op, the Pedi-IKDC and HSS Pedi-FABS were 96.54 ± 5 and 22.6 ± 5, respectively. Subjects demonstrated return to pre-operative Tegner Activity scores (8.42 vs. 8.17, p=0.33). Normalized hip abduction strength was significantly stronger in AFF (1.05 Nm/kg) vs. UNAFF (0.93 Nm/kg, p=0.02). Conclusion: Overall, there were no clinically significant differences, or asymmetry, in functional knee valgus in subjects following combined intra- and extra-articular iliotibial band ACL reconstruction during a drop landing or single leg squat. Young athletes can be expected to return to pre-operative activity levels and demonstrate appropriate knee valgus control following this physeal-sparing ACL reconstruction.


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