scholarly journals Valgus Knee Angle during Drop Landing in Female and Male Physical Education Major Undergraduate Students

2010 ◽  
Vol 16 (2) ◽  
pp. 65-78
Author(s):  
Ka lam SAM
Keyword(s):  
Anterior Cruciate Ligament ◽  
Knee Flexion ◽  
Muscle Activation ◽  
Cruciate Ligament ◽  
Frontal Plane ◽  
Biceps Femoris ◽  
Initial Contact ◽  
Valgus Knee ◽  
Knee Angle ◽  
Anterior Cruciate

LANGUAGE NOTE | Document text in English; abstract also in Chinese. Gender differences in lower extremity landing mechanics and muscle activation have been identified as potential causative factors leading to the increased incidence of anterior cruciate ligament (ACL) injuries in female athletes. Valgus knee alignment places greater strain on the anterior cruciate ligament than a more neutral alignment. Biceps Femoris (BF) may provide dynamic stability to the knee joint during landing, decreasing knee valgus and preventing placing strain on the anterior cruciate ligament. The purpose of this study was to determine if frontal-plane knee angle and Biceps Femoris (BF) activation differ between the sexes at initial contact (IC) and maximal knee flexion (MKF) during a drop landing. Nine male and eight female healthy subjects volunteered to participate in this study. Frontal-plane knee angle and BF average root mean square (aRMS) amplitude were measured using BTS (Bioengineering Technology & Systems) electromyography, video acquisition system and Kistler force platform. It was found that at initial contact, women landed in valgus, and men landed in varus (P < .001). At maximal knee flexion, men reached a greater varus position than women (P < .001). Women’s BF aRMS amplitude was less than men. At initial contact, BF aRMS amplitude significantly differed between groups (P < .05). However, no significance difference between groups at maximal knee flexion (P > .05). To conclude, women tended to land in more knee valgus than men. At initial contact, women performed different and less BF muscle activation than men. The stabilization mechanism in landing knee motion between initial contact and maximal knee flexion is still unknown. 股二頭肌能通過減輕膝外翻程度來增加著地時膝關節的穩定性，從而減輕前十字韌帶受到的張力。有研究表明，不同群體之間下肢著地技術和肌肉活動情況的差異是增加女子運動員前十字韌帶受傷幾率的兩大潛在因素。當膝外翻時，十字韌帶受到比膝蓋處於中立位時更大的張力。本研究通過運用Kistler測力台，肌電圖，以及BTS視頻採集系統對17名(男=9，女=8)主修體育的本科生進行測量，目的在於討論著地瞬間膝關節的角度和股二頭肌活動是否存在性別差異，以及測定著地緩衝後的最大膝角和股二頭肌活動是否存在性別差異。結果發現，在著地瞬間，女性較男性更容易出現膝外翻現象(p<.001)。肌電圖顯示，女性股二頭肌振幅 比男性要小且男女之間存在顯著性差異(p<.05)，但當緩衝至最大膝角時，男女之間的差異並不顯著(p>.05)。著地過程中，下肢肌肉的穩定機制與膝部運動的關係有待進一步探討。

scholarly journals Effects of Transverse and Frontal Plane Knee Laxity on Hip and Knee Neuromechanics during Drop Landings

2009 ◽  
Vol 37 (9) ◽  
pp. 1821-1830 ◽  
Author(s):  
Sandra J. Shultz ◽  
Randy J. Schmitz
Keyword(s):  
Anterior Cruciate Ligament ◽  
Internal Rotation ◽  
Muscle Activation ◽  
Cruciate Ligament ◽  
Frontal Plane ◽  
Knee Laxity ◽  
Transverse Plane ◽  
Ligament Injury ◽  
Drop Jump ◽  
Anterior Cruciate

Background Varus-valgus (LAXVV) and internal-external (LAXIER) rotational knee laxity have received attention as potential contributing factors in anterior cruciate ligament injury. This study compared persons with above- and below-average LAXVV and LAXIER values on hip and knee neuromechanics during drop jump landings. Hypothesis People with greater LAXVV and LAXIER values will have greater challenges controlling frontal and transverse plane knee motions, as evidenced by greater joint excursions, joint moments, and muscle activation levels during the landing phase. Study Design Descriptive laboratory study. Methods Recreationally active participants (52 women and 44 men) between 18 and 30 years old were measured for LAXVV and LAXIER and for their muscle activation and transverse and frontal plane hip and knee kinetics and kinematics during the initial landing phase of a drop jump. The mean value was obtained for each sex, and those with above-average values on LAXVV and LAXIER (LAXHIGH = 17 women, 16 men) were compared with those with below-average values (LAXLOW = 18 women, 17 men). Results Women with LAXHIGH verus LAXLOW were initially positioned in greater hip adduction and knee valgus and also produced more prolonged internal hip adduction and knee varus moments as they moved toward greater hip adduction and internal rotation as the landing progressed. These patterns in LAX HIGH women were accompanied by greater prelanding and postlanding muscle activation amplitudes. Men with LAXHIGH versus LAXLOW also demonstrated greater hip adduction motion and produced greater internal hip internal rotation and knee varus and internal rotation moments. Conclusion Participants with greater LAXVV and LAXIER landed with greater hip and knee transverse and frontal plane hip and knee motions. Clinical Relevance People (especially, women) with increased frontal and transverse plane knee laxity demonstrate motions associated with noncontact anterior cruciate ligament injury mechanisms.

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

2013 ◽  
Vol 48 (3) ◽  
pp. 306-313 ◽  
Author(s):  
Nelson Cortes ◽  
Eric Greska ◽  
Roger Kollock ◽  
Jatin Ambegaonkar ◽  
James A. Onate
Keyword(s):  
Anterior Cruciate Ligament ◽  
Lower Extremity ◽  
Knee Flexion ◽  
Cruciate Ligament ◽  
Ligament Injury ◽  
Initial Contact ◽  
Fatigue Protocol ◽  
Lower Extremity Biomechanics ◽  
Anterior Cruciate ◽  
Hip Flexion

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 sidestep-cutting task (SS). Design: Controlled laboratory study. Setting: Laboratory. Patients or Other Participants: Eighteen uninjured female collegiate soccer players (age = 19.2 ± 0.9 years, height = 1.66 ± 0.5 m, mass = 61.6 ± 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 hip- and 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 (−17° ± 5°) to 50% fatigue (−16° ± 6°) and to 100% fatigue (−14° ± 4°) (F2,34 = 5.112, P = .004). Knee flexion at peak stance increased from prefatigue (−52.9° ± 5.6°) to 50% fatigue (−56.1° ± 7.2°) but decreased from 50% to 100% fatigue (−50.5° ± 7.1°) (F2,34 = 8.282, P = 001). Knee-adduction moment at peak stance increased from prefatigue (0.49 ± 0.23 Nm/kgm) to 50% fatigue (0.55 ± 0.25 Nm/kgm) but decreased from 50% to 100% fatigue (0.37 ± 0.24) (F2,34 = 3.755, P = 03). Hip-flexion angle increased from prefatigue (45.4° ± 10.9°) to 50% fatigue (46.2° ± 11.2°) but decreased from 50% to 100% fatigue (40.9° ± 11.3°) (F2,34 = 6.542, P = .004). Hip flexion at peak stance increased from prefatigue (49.8° ± 9.9°) to 50% fatigue (52.9° ± 12.1°) but decreased from 50% to 100% fatigue (46.3° ± 12.9°) (F2,34 = 8.639, P = 001). Hip-abduction angle at initial contact decreased from prefatigue (−13.8° ± 6.6°) to 50% fatigue (−9.1° ± 6.5°) and to 100% fatigue (−7.8° ± 6.5°) (F2,34 = 11.228, P &lt; .001). Hip-adduction moment decreased from prefatigue (0.14 ± 0.13 Nm/kgm) to 50% fatigue (0.08 ± 0.13 Nm/kgm) and to 100% fatigue (0.06 ± 0.05 Nm/kg) (F2,34 = 5.767, P = .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.

Jump Landing Strategies in Male and Female College Athletes and the Implications of Such Strategies for Anterior Cruciate Ligament Injury

2003 ◽  
Vol 31 (2) ◽  
pp. 233-240 ◽  
Author(s):  
Ray Fagenbaum ◽  
Warren G. Darling
Keyword(s):  
Anterior Cruciate Ligament ◽  
Knee Flexion ◽  
Muscle Activation ◽  
Female Athletes ◽  
Cruciate Ligament ◽  
Ligament Injury ◽  
Basketball Players ◽  
College Basketball ◽  
Anterior Cruciate ◽  
Knee Muscle

Background: Female athletes are more likely than male athletes to injure the anterior cruciate ligament. Causes of this increased injury incidence in female athletes remain unclear, despite numerous investigations. Hypothesis: Female athletes will exhibit lower hamstring muscle activation and smaller knee flexion angles than male athletes during jump landings, especially when the knee muscles are fatigued. Study Design: Controlled laboratory study. Methods: Eight female and six male varsity college basketball athletes with no history of knee ligament injury performed jump landings on the dominant leg from a maximum height jump and from 25.4 cm and 50.8 cm high platforms under nonfatigued and fatigued conditions. Knee joint angle and surface electromyographic signals from the quadriceps, hamstring, and gastrocnemius muscles were recorded. Results: Women landed with greater knee flexion angles and greater knee flexion accelerations than men. Knee muscle activation patterns were generally similar in men and women. Conclusion: As compared with male college basketball players, female college basketball players did not exhibit altered knee muscle coordination characteristics that would predispose them to anterior cruciate ligament injury when landing from jumps. This conclusion is made within the parameters of this study and based on the observation that hamstring muscle activation was similar for both groups. The greater knee flexion we observed in the female subjects would be expected to decrease their risk of injury. Clinical Relevance: Factors other than those evaluated in this study need to be considered when attempting to determine the reasons underlying the increased incidence of anterior cruciate ligament injuries consistently observed in elite female athletes.

scholarly journals Effect of knee angle on quadriceps strength and activation after anterior cruciate ligament reconstruction

2015 ◽  
Vol 119 (3) ◽  
pp. 223-231 ◽  
Author(s):  
Chandramouli Krishnan ◽  
Paul Theuerkauf
Keyword(s):  
Anterior Cruciate Ligament ◽  
Acl Reconstruction ◽  
Knee Flexion ◽  
Functional Performance ◽  
Cruciate Ligament ◽  
Quadriceps Strength ◽  
Contractile Property ◽  
Knee Angle ◽  
Peripheral Muscle ◽  
Anterior Cruciate

Quadriceps strength and activation deficits after anterior cruciate ligament (ACL) injury or surgery are typically evaluated at joint positions that are biomechanically advantageous to the quadriceps muscle. However, the effect of knee joint position and the associated changes in muscle length on strength and activation is currently unknown in this population. Here, we examined the effect of knee angle on quadriceps strength, activation, and electrically evoked torque in individuals with ACL reconstruction. Furthermore, we evaluated whether knee angle mediated the relationship between quadriceps weakness and functional performance after ACL reconstruction. Knee strength and activation were tested bilaterally at 90° and 45° of knee flexion in 11 subjects with ACL reconstruction using an interpolated triplet technique. The magnitude of electrically evoked torque at rest was used to quantify peripheral muscle contractile property changes, and the single-leg hop for distance test was used to evaluate functional performance. The results indicated that although quadriceps strength deficits were similar between knee angles, voluntary activation deficits were significantly higher in the reconstructed leg at 45° of knee flexion. On the contrary, the side-to-side evoked torque at rest ratio [i.e., (reconstructed/nonreconstructed) × 100] was significantly lower at 90° than at 45° of knee flexion. The association between quadriceps strength and functional performance was stronger at 45° of knee flexion. The results provide novel evidence that quadriceps activation is selectively affected at 45° of knee flexion and emphasize the importance of assessing quadriceps strength and activation at this position when feasible because it better captures activation deficits.

The Effect of Functional Knee Braces on Muscular Contributions to Joint Rotational Stiffness in Anterior Cruciate Ligament–Deficient and –Reconstructed Patients

2019 ◽  
Vol 35 (5) ◽  
pp. 344-352
Author(s):  
Aaron Derouin ◽  
Jim R. Potvin
Keyword(s):  
Anterior Cruciate Ligament ◽  
Knee Joint ◽  
Knee Flexion ◽  
Muscle Activation ◽  
Cruciate Ligament ◽  
Rotational Stiffness ◽  
Flexion Extension ◽  
Knee Braces ◽  
Anterior Cruciate ◽  
Acl Deficient

Functional knee braces are frequently prescribed by physicians to ameliorate the function of individuals with anterior cruciate ligament (ACL) injuries. These braces have been shown in the literature to potentially enhance knee stability by augmenting muscle activation patterns and the timing of muscle response to perturbations. However, very few techniques are available in the literature to quantify how those modifications in lower-limb muscle activity influence stability of the knee. The aim of the present study was to quantify the effect of an off-the-shelf functional knee brace on muscle contributions to knee joint rotational stiffness in ACL-deficient and ACL-reconstructed patients. Kinematic, electromyography, and kinetic data were incorporated into an electromyography-driven model of the lower extremity to calculate individual and total muscle contributions to knee joint rotational stiffness about the flexion–extension axis, for 4 independent variables: leg condition (contralateral uninjured, unbraced ACL injured, and braced ACL injured); knee flexion (5°–10°, 20°–25°, and 30°–35°); squat stability condition (stable and unstable); and injury status (ACL deficient and ACL reconstructed). Participants had significantly higher (P < .05,η2 = .018) total knee joint rotational stiffness values while wearing the brace compared with the control leg. A 2-way interaction effect between stability and knee flexion (P < .05,η2 = .040) for total joint rotational stiffness was also found.

scholarly journals Rapid Posterior Tibial Reduction After Noncontact Anterior Cruciate Ligament Rupture: Mechanism Description From a Video Analysis

2020 ◽  
Vol 12 (5) ◽  
pp. 462-469 ◽  
Author(s):  
Alberto Grassi ◽  
Filippo Tosarelli ◽  
Piero Agostinone ◽  
Luca Macchiarola ◽  
Stefano Zaffagnini ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Video Analysis ◽  
Knee Flexion ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Soccer Players ◽  
Initial Contact ◽  
Acl Injuries ◽  
Posterior Tibial ◽  
Anterior Cruciate

Background: The mechanisms of noncontact anterior cruciate ligament (ACL) injuries are an enormously debated topic in sports medicine; however, the late phases of injury have not yet been investigated. Hypothesis: A well-defined posterior tibial translation can be visualized with its timing and patterns of knee flexion after ACL injury. Study Design: Case series. Level of Evidence: Level 4. Methods: A total of 137 videos of ACL injuries in professional male football (soccer) players were screened for a sudden posterior tibial reduction (PTR) in the late phase of noncontact ACL injury mechanism. The suitable videos were analyzed using Kinovea software for sport video analysis. The time of initial contact of the foot with the ground, the foot lift, the start of tibial reduction, and the end of tibial reduction were assessed. Results: A total of 21 videos exhibited a clear posterior tibial reduction of 42 ± 11 ms, after an average of 229 ± 81 ms after initial contact. The tibial reduction occurred consistently within the first 50 to 60 ms after foot lift (55 ± 30 ms) and with the knee flexed between 45° and 90° (62%) or more than 90° (24%). Conclusion: A rapid posterior tibial reduction is consistently present in the late phases of noncontact ACL injuries in some male soccer players, with a consistent temporal relationship between foot lift from the ground and consistent degrees of knee flexion near or above 90°. Clinical Relevance: This study provides insight into the late phases of ACL injury. The described mechanism, although purely theoretical, could be responsible for commonly observed intra-articular lesions.

scholarly journals Single-Leg Landings Following a Volleyball Spike May Increase the Risk of Anterior Cruciate Ligament Injury More Than Landing on Both-Legs

2020 ◽  
Vol 11 (1) ◽  
pp. 130
Author(s):  
Datao Xu ◽  
Xinyan Jiang ◽  
Xuanzhen Cen ◽  
Julien S. Baker ◽  
Yaodong Gu
Keyword(s):  
Anterior Cruciate Ligament ◽  
Knee Flexion ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Flexion Angle ◽  
Ligament Injury ◽  
Time Range ◽  
Acl Injuries ◽  
Volleyball Players ◽  
Anterior Cruciate

Volleyball players often land on a single leg following a spike shot due to a shift in the center of gravity and loss of balance. Landing on a single leg following a spike may increase the probability of non-contact anterior cruciate ligament (ACL) injuries. The purpose of this study was to compare and analyze the kinematics and kinetics differences during the landing phase of volleyball players using a single leg (SL) and double-leg landing (DL) following a spike shot. The data for vertical ground reaction forces (VGRF) and sagittal plane were collected. SPM analysis revealed that SL depicted a smaller knee flexion angle (about 13.8°) and hip flexion angle (about 10.8°) during the whole landing phase, a greater knee and hip power during the 16.83–20.45% (p = 0.006) and 13.01–16.26% (p = 0.008) landing phase, a greater ankle plantarflexion angle and moment during the 0–41.07% (p < 0.001) and 2.76–79.45% (p < 0.001) landing phase, a greater VGRF during the 5.87–8.25% (p = 0.029), 19.75–24.14% (p = 0.003) landing phase when compared to DL. Most of these differences fall within the time range of ACL injury (30–50 milliseconds after landing). To reduce non-contact ACL injuries, a landing strategy of consciously increasing the hip and knee flexion, and plantarflexion of the ankle should be considered by volleyball players.

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