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Robson Dias Scoz, Cesar F. Amorim, Bruno O.A. Mazziotti, Rubens A. Da Silva, Edgar R. Vieira, Alexandre D. Lopes and Ronaldo E.C.D. Gabriel

The knee joint provides functionality and independence to the individual and almost half of knee ligament injuries occur to the anterior cruciate ligament (ACL). 1 , 2 Data from the United States indicate an incidence of approximately 200,000 ACL injuries per year, 70% of these injuries occurring

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Caroline Lisee, Tom Birchmeier, Arthur Yan, Brent Geers, Kaitlin O’Hagan, Callum Davis and Christopher Kuenze

, Gage WH . The analysis of knee joint loading during drop landing from different heights and under different instruction sets in healthy males . Sports Med Open . 2017 ; 3 ( 1 ): 6 . PubMed ID: 28101732 doi: 10.1186/s40798-016-0072-x 28101732 29. Leppanen M , Pasanen K , Kujala UM , et

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Rodrigo R. Bini, Aline C. Tamborindeguy and Carlos B. Mota

Context:

It is not clear how noncyclists control joint power and kinematics in different mechanical setups (saddle height, workload, and pedaling cadence). Joint mechanical work contribution and kinematics analysis could improve our comprehension of the coordinative pattern of noncyclists and provide evidence for bicycle setup to prevent injury.

Objective:

To compare joint mechanical work distribution and kinematics at different saddle heights, workloads, and pedaling cadences.

Design:

Quantitative experimental research based on repeated measures.

Setting:

Research laboratory.

patients:

9 healthy male participants 22 to 36 years old without competitive cycling experience.

Intervention:

Cycling on an ergometer in the following setups: 3 saddle heights (reference, 100% of trochanteric height; high, + 3 cm; and low, − 3 cm), 2 pedaling cadences (40 and 70 rpm), and 3 workloads (0, 5, and 10 N of braking force).

Main Outcome Measures:

Joint kinematics, joint mechanical work, and mechanical work contribution of the joints.

Results:

There was an increased contribution of the ankle joint (P = .04) to the total mechanical work with increasing saddle height (from low to high) and pedaling cadence (from 40 to 70 rpm, P < .01). Knee work contribution increased when saddle height was changed from high to low (P < .01). Ankle-, knee-, and hip-joint kinematics were affected by saddle height changes (P < .01).

Conclusions:

At the high saddle position it could be inferred that the ankle joint compensated for the reduced knee-joint work contribution, which was probably effective for minimizing soft-tissue damage in the knee joint (eg, anterior cruciate ligament and patellofemoral cartilage). The increase in ankle work contribution and changes in joint kinematics associated with changes in pedaling cadence have been suggested to indicate poor pedaling-movement skill.

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David Hawkins and Mark Smeulders

The purpose of this study was to determine if the Hill model, used to describe the force-velocity relationship for isolated tetanically stimulated muscle, could be modified and used to describe the torque-velocity behavior of the knee for maximally and submaximally stimulated quadriceps and hamstrings muscles. Fourteen subjects performed both knee flexion and extension movements at 100%, 70%, and 40% of maximum isometric effort. For each effort level, the knee was allowed to move against resistances equal to 75%, 50%, 25%, and 0% of the specified effort level. An electrogoniometer quantified knee angle. Knee velocity was determined by numerically differentiating the joint angle data. Torque-velocity-activation (or effort level) data were determined for each trial. Model parameters were determined to give the best fit to the data for each subject. Average parameter values were determined for each gender and for the entire group. The modified Hill-type model accurately described the relationship between torque, velocity, and muscle activation level for subject-specific parameters but not for parameters averaged across genders or the entire group.

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Rebecca L. Lambach, Jay W. Young, David C. Flanigan, Robert A. Siston and Ajit M.W. Chaudhari

Linemen are at high risk for knee cartilage injuries and osteoarthritis. High-intensity movements from squatting positions (eg, 3-point stance) may produce high joint loads, increasing the risk for cartilage damage. We hypothesized that knee moments and joint reaction forces during lineman-specific activities would be greater than during walking or jogging. Data were collected using standard motion analysis techniques. Fifteen NCAA linemen (mean ± SD: height = 1.86 ± 0.07 m, mass = 121.45 ± 12.78 kg) walked, jogged, and performed 3 unloaded lineman-specific blocking movements from a 3-point stance. External 3-dimensional knee moments and joint reaction forces were calculated using inverse dynamics equations. MANOVA with subsequent univariate ANOVA and post hoc Tukey comparisons were used to determine differences in peak kinetic variables and the flexion angles at which they occurred. All peak moments and joint reaction forces were significantly higher during jogging than during all blocking drills (all P < .001). Peak moments occurred at average knee flexion angles > 70° during blocking versus < 44° in walking or jogging. The magnitude of moments and joint reaction forces when initiating movement from a 3-point stance do not appear to increase risk for cartilage damage, but the high flexion angles at which they occur may increase risk on the posterior femoral condyles.

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Joshua M. Drouin, Peggy A. Houglum, David H. Perrin and Bruce M. Gansneder

Objective:

To determine the relationship between weight-bearing (WB) and non-weight-bearing (NWB) joint reposition sense (JRS) and a functional hop test (FH) and to compare performance on these parameters between athletes and nonathletes.

Design:

Repeated-measures ANOVA and Pearson correlations.

Setting:

Research laboratory.

Participants:

40 men (age = 20.8 ± 1.7 y; ht = 176.9 ± 5.8 cm; wt = 82.6 ± 9.5 kg): 20 lacrosse players and 20 nonathletes.

Main Outcome Measures:

Ability to actively reproduce 30° of knee flexion in the WB and NWB conditions and functional performance on a single-leg crossover-hop test.

Results:

No significant correlations were observed between JRS and FH in athletes and nonathletes. No significant differences were observed between athletes and nonathletes in JRS. All participants were significantly more accurate at WB than at NWB JRS.

Conclusions:

There appears to be no relationship between WB or NWB JRS and functional performance, regardless of one’s physical activity level

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Andrew L. McDonough and Joseph P. Weir

The purpose of this case study was to investigate reflex inhibition of the quadriceps femoris in a subject with postsurgical edema of the left knee. The subject was a 45-year-old male with a traumatic knee injury with resultant edema who underwent elective arthroscopic surgery. Reflex inhibition was assessed by H-reflex elicitation in the femoral nerve and surface electromyography of the quadriceps. To assess the degree of edema, direct circumferential measurements were taken. On the first presurgical visit, the left knee demonstrated mild edema with a decrease in H-reflex amplitudes. Two days after surgery, a further reduction in amplitudes and more swelling were demonstrated followed by an increase in amplitudes and a reduction in edema on the 28th postoperative day. These findings document a relationship between reflex inhibition and joint swelling that was previously described in experimental models where joint edema was simulated.

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Wendy L. Hurley, Craig Denegar and William E. Buckley

Context:

The relationship between clinical judgments of anterior knee laxity and instrumented measurement of anterior tibial translation is unclear.

Objective:

To examine the relationship between certified athletic trainers’ grading of anterior knee laxity and instrumented measurements of anterior tibial translation.

Design:

Randomized, blinded, clinical assessment.

Setting:

Laboratory.

Participants:

Model patients receiving evaluation of anterior knee laxity.

Intervention:

Twelve model patients were evaluated using a MEDmetric® KT1000™ knee ligament Arthrometer® to establish instrumented measurements of anterior translation values at the tibio-femoral joint. Twenty-two certified athletic trainers were provided with operational definitions of potential laxity grades and examined the model patients to make judgments of anterior knee laxity.

Main Outcome Measures:

Correlation between clinical judgments and instrumented measurements of anterior tibial translation.

Results:

Clinical judgments and instrumented measurements were mutually independent.

Conclusions:

Anterior tibial translation grading by certified athletic trainers should be interpreted with caution during clinical decision-making.

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Michael J. Higgins and David H. Perrin

In this study, joint reposition sense of the knee in a non-weight-bearing (NWB) state and that in a weight-bearing (WB) state were compared, and it was determined whether a significant relationship existed between knee displacement (KD) and joint reposition sense. The dominant knees of 8 male and 12 female subjects (age 19–26 years, M ± SD = 21.5 ± 2.06) who had no previous history of knee dysfunction were tested for accuracy of angular reproduction in the WB and NWB states. There was a significant difference in the accuracy of angular repositioning between the two conditions, with the WB test having less deviation from the predetermined angle. There was a weak relationship between KD and the ability to reproduce specific angles of the knee. These results suggest that the WB or closed chain state of the knee was more accurate in the determination of joint position sense than the NWB or open chain condition.

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Lukas D. Linde, Jessica Archibald, Eve C. Lampert and John Z. Srbely

approach such that the reactive forces and resultant moment of the trunk and left leg center of mass were used along with anthropometric mass segments 21 to calculate the reactive forces and moment at the right hip joint, before being applied to the right knee joint. 21 Peak knee abduction moments were