scholarly journals Quadriceps and Hamstrings Coactivation During Common Therapeutic Exercises

2012 ◽  
Vol 47 (4) ◽  
pp. 396-405 ◽  
Author(s):  
Rebecca L. Begalle ◽  
Lindsay J. DiStefano ◽  
Troy Blackburn ◽  
Darin A. Padua
Keyword(s):  
Repeated Measures ◽  
Shear Force ◽  
Injury Risk ◽  
Cruciate Ligament ◽  
Activity Level ◽  
Knee Valgus ◽  
Emg Amplitude ◽  
Therapeutic Exercises ◽  
Anterior Tibial ◽  
Post Hoc

Context: Anterior tibial shear force and knee valgus moment increase anterior cruciate ligament (ACL) loading. Muscle coactivation of the quadriceps and hamstrings influences anterior tibial shear force and knee valgus moment, thus potentially influencing ACL loading and injury risk. Therefore, identifying exercises that facilitate balanced activation of the quadriceps and hamstrings might be beneficial in ACL injury rehabilitation and prevention. Objective: To quantify and compare quadriceps with hamstrings coactivation electromyographic (EMG) ratios during commonly used closed kinetic chain exercises. Design: Cross-sectional study. Setting: Research laboratory. Patients or Other Participants: Twenty-seven healthy, physically active volunteers (12 men, 15 women; age = 22.1 ± 3.1 years, height = 171.4 ± 10 cm, mass = 72.4 ± 16.7 kg). Intervention(s): Participants completed 9 separate closed chain therapeutic exercises in a randomized order. Main Outcome Measure(s): Surface electromyography quantified the activity level of the vastus medialis (VM), vastus lateralis (VL), medial hamstrings (MH), and biceps femoris (BF) muscles. The quadriceps-to-hamstrings (Q:H) coactivation ratio was computed as the sum of average quadriceps (VM, VL) EMG amplitude divided by the sum of average hamstrings (MH, BF) EMG amplitude for each trial. We used repeated-measures analyses of variance to compare Q:H ratios and individual muscle contributions across exercises (α = .05), then used post hoc Tukey analyses. Results: We observed a main effect for exercise (F3,79 = 22.6, P < .001). The post hoc Tukey analyses revealed smaller Q:H ratios during the single-limb dead lift (2.87 ± 1.77) than the single-limb squat (5.52 ± 2.89) exercise. The largest Q:H ratios were observed during the transverse-lunge (7.78 ± 5.51, P < .001), lateral-lunge (9.30 ± 5.53, P < .001), and forward-lunge (9.70 ± 5.90, P < .001) exercises. Conclusions: The most balanced (smallest) coactivation ratios were observed during the single-limb dead-lift, lateral-hop, transverse-hop, and lateral band-walk exercises. These exercises potentially could facilitate balanced activation in ACL rehabilitation and injury-prevention programs. They also could be used in postinjury rehabilitation programs in a safe and progressive manner.

scholarly journals Passive Hip Range-of-Motion Values Across Sex and Sport

2018 ◽  
Vol 53 (6) ◽  
pp. 560-567 ◽  
Author(s):  
Jennifer A. Hogg ◽  
Randy J. Schmitz ◽  
Anh-Dung Nguyen ◽  
Sandra J. Shultz
Keyword(s):  
Range Of Motion ◽  
Repeated Measures ◽  
National Collegiate Athletic Association ◽  
External Rotation ◽  
Cruciate Ligament ◽  
Knee Valgus ◽  
Cross Sectional ◽  
Increased Risk ◽  
Hip Range Of Motion ◽  
Cross Country

Context:  Greater passive hip range of motion (ROM) has been associated with greater dynamic knee valgus and thus the potential for increased risk of anterior cruciate ligament injuries. Normative data for passive hip ROM by sex are lacking. Objective:  To establish and compare passive hip ROM values by sex and sport and to quantify side-to-side differences in internal-rotation ROM (ROMIR), external-rotation ROM (ROMER), and total ROM (ROMTOT). Design:  Cross-sectional study. Setting:  Station-based, preparticipation screening. Patients or Other Participants:  A total of 339 National Collegiate Athletic Association Division I athletes, consisting of 168 women (age = 19.2 ± 1.2 years, height = 169.0 ± 7.2 cm, mass = 65.3 ± 10.2 kg) and 171 men (age = 19.4 ± 1.3 years, height = 200.0 ± 8.6 cm, mass = 78.4 ± 12.0 kg) in 6 sports screened over 3 years: soccer (58 women, 67 men), tennis (20 women, 22 men), basketball (28 women, 22 men), softball or baseball (38 women, 31 men), cross-country (18 women, 19 men), and golf (6 women, 10 men). Main Outcome Measure(s):  Passive hip ROM was measured with the athlete lying prone with the hip abducted to 20° to 30° and knee flexed to 90°. The leg was passively internally and externally rotated until the point of sacral movement. Three measures were averaged for each direction and leg and used for analysis. We compared ROMIR, ROMER, ROMTOT (ROMTOT = ROMIR + ROMER), and relative ROM (ROMREL = ROMIR − ROMER) between sexes and among sports using separate 2 × 6 repeated-measures analyses of variance. Results:  Women had greater ROMIR (38.1° ± 8.2° versus 28.6° ± 8.4°; F1,327 = 91.74, P < .001), ROMTOT (72.1° ± 10.6° versus 64.4° ± 10.1°; F1,327 = 33.47, P < .001), and ROMREL (1.5° ± 16.0° versus −7.6° ± 16.5°; F1,327 = 37.05, P < .001) than men but similar ROMER (34.0° ± 12.2° versus 35.8° ± 11.5°; F1,327 = 1.65, P = .20) to men. Cross-country athletes exhibited greater ROMIR (37.0° ± 9.3° versus 30.9° ± 9.4° to 33.3° ± 9.5°; P = .001) and ROMREL (5.9° ± 18.3° versus −9.6° ± 16.9° to −2.7° ± 17.3°; P = .001) and less ROMER (25.7° ± 7.5° versus 35.0° ± 13.0° to 40.2° ± 12.0°; P < .001) than basketball, soccer, softball or baseball, and tennis athletes. They also displayed less ROMTOT (62.7° ± 8.1° versus 70.0° ± 9.1° to 72.9° ± 11.9°; P < .001) than basketball, softball or baseball, and tennis athletes. Conclusions:  Women had greater ROMIR than men, resulting in greater ROMTOT and ROMREL. Researchers should examine the extent to which this greater bias toward ROMIR may explain women's greater tendency for dynamic knee valgus. With the exception of cross-country, ROM values were similar across sports. The clinical implications of these aberrant cross-country values require further study.

Preliminary Evaluation of Knee Kinetics in Female Athletes on Hormonal Contraceptives

2019 ◽  
Vol 41 (02) ◽  
pp. 113-118
Author(s):  
Gabrielle Gilmer ◽  
Gretchen D. Oliver
Keyword(s):  
Injury Risk ◽  
Female Athletes ◽  
Cruciate Ligament ◽  
Reaction Force ◽  
Acl Injury ◽  
Hormonal Contraceptives ◽  
Preliminary Evaluation ◽  
Knee Valgus ◽  
Time Points ◽  
Acl Injury Risk

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.

The Effect of Thigh Marker Placement on Knee Valgus Angles in Vertical Drop Jumps and Sidestep Cutting

2015 ◽  
Vol 31 (4) ◽  
pp. 269-274 ◽  
Author(s):  
Kam-Ming Mok ◽  
Eirik Klami Kristianslund ◽  
Tron Krosshaug
Keyword(s):  
Cross Talk ◽  
Injury Risk ◽  
Cruciate Ligament ◽  
Neuromuscular Control ◽  
Acl Injury ◽  
Knee Valgus ◽  
Substantial Impact ◽  
Drop Jumps ◽  
The Cross ◽  
Marker Cluster

Knee valgus angles measured in sidestep cutting and vertical drop jumps are key variables in research on anterior cruciate ligament (ACL) injury causation. These variables are also used to quantify knee neuromuscular control and ACL injury risk. The aims of the current study were to (1) quantify the differences in the calculated knee valgus angles between 6 different thigh marker clusters, (2) investigate the trial ranking based on their knee valgus angles, and (3) investigate the influence of marker clusters on the cross-talk effect. Elite female handball and football players (n = 41) performed sidestep cutting and vertical drop jumping motions. We found systematic differences up to almost 15° of peak valgus between the marker sets in the drop jump test. The Spearman’s rank correlation coefficient varied from .505 to .974 among the 6 marker sets. In addition, the cross-talk effect varied considerably between the marker clusters. The results of the current study indicate that the choice of thigh marker cluster can have a substantial impact on the magnitude of knee valgus angle, as well as the trial ranking. A standardized thigh marker cluster, including nonanatomical landmark, is needed to minimize the variation of the measurement.

scholarly journals Stiff Landings, Core Stability, and Dynamic Knee Valgus: A Systematic Review on Documented Anterior Cruciate Ligament Ruptures in Male and Female Athletes

2021 ◽  
Vol 18 (7) ◽  
pp. 3826
Author(s):  
Joseph Larwa ◽  
Conrad Stoy ◽  
Ross S. Chafetz ◽  
Michael Boniello ◽  
Corinna Franklin
Keyword(s):  
Systematic Review ◽  
Anterior Cruciate Ligament ◽  
Injury Risk ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Core Stability ◽  
Knee Valgus ◽  
Acl Injuries ◽  
Male And Female ◽  
Anterior Cruciate

Anterior cruciate ligament (ACL) injuries are the most common ligament injury of the knee, accounting for between 100,000 and 200,000 injuries among athletes per year. ACL injuries occur via contact and non-contact mechanisms, with the former being more common in males and the later being more common in females. These injuries typically require surgical repair and have relatively high re-rupture rates, resulting in a significant psychological burden for these individuals and long rehabilitation times. Numerous studies have attempted to determine risk factors for ACL rupture, including hormonal, biomechanical, and sport- and gender-specific factors. However, the incidence of ACL injuries continues to rise. Therefore, we performed a systematic review analyzing both ACL injury video analysis studies and studies on athletes who were pre-screened with eventual ACL injury. We investigated biomechanical mechanisms contributing to ACL injury and considered male and female differences. Factors such as hip angle and strength, knee movement, trunk stability, and ankle motion were considered to give a comprehensive, joint by joint analysis of injury risk and possible roles of prevention. Our review demonstrated that poor core stability, landing with heel strike, weak hip abduction strength, and increased knee valgus may contribute to increased ACL injury risk in young athletes.

scholarly journals Hamstrings Stiffness and Landing Biomechanics Linked to Anterior Cruciate Ligament Loading

2013 ◽  
Vol 48 (6) ◽  
pp. 764-772 ◽  
Author(s):  
J. Troy Blackburn ◽  
Marc F. Norcross ◽  
Lindsey N. Cannon ◽  
Steven M. Zinder
Keyword(s):  
Anterior Cruciate Ligament ◽  
Knee Flexion ◽  
Shear Force ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Knee Extension ◽  
High Stiffness ◽  
Landing Biomechanics ◽  
Anterior Tibial ◽  
Anterior Cruciate

Context: Greater hamstrings stiffness is associated with less anterior tibial translation during controlled perturbations. However, it is unclear how hamstrings stiffness influences anterior cruciate ligament (ACL) loading mechanisms during dynamic tasks. Objective: To evaluate the influence of hamstrings stiffness on landing biomechanics related to ACL injury. Design: Cross-sectional study. Setting: Research laboratory. Patients or Other Participants: A total of 36 healthy, physically active volunteers (18 men, 18 women; age = 23 ± 3 years, height = 1.8 ± 0.1 m, mass = 73.1 ± 16.6 kg). Intervention(s): Hamstrings stiffness was quantified via the damped oscillatory technique. Three-dimensional lower extremity kinematics and kinetics were captured during a double-legged jump-landing task via a 3-dimensional motion-capture system interfaced with a force plate. Landing biomechanics were compared between groups displaying high and low hamstrings stiffness via independent-samples t tests. Main Outcome Measure(s): Hamstrings stiffness was normalized to body mass (N/m·kg−1). Peak knee-flexion and -valgus angles, vertical and posterior ground reaction forces, anterior tibial shear force, internal knee-extension and -varus moments, and knee-flexion angles at the instants of each peak kinetic variable were identified during the landing task. Forces were normalized to body weight, whereas moments were normalized to the product of weight and height. Results: Internal knee-varus moment was 3.6 times smaller in the high-stiffness group (t22 = 2.221, P = .02). A trend in the data also indicated that peak anterior tibial shear force was 1.1 times smaller in the high-stiffness group (t22 = 1.537, P = .07). The high-stiffness group also demonstrated greater knee flexion at the instants of peak anterior tibial shear force and internal knee-extension and -varus moments (t22 range = 1.729–2.224, P < .05). Conclusions: Greater hamstrings stiffness was associated with landing biomechanics consistent with less ACL loading and injury risk. Musculotendinous stiffness is a modifiable characteristic; thus exercises that enhance hamstrings stiffness may be important additions to ACL injury-prevention programs.

Knee Valgus Versus Knee Abduction Angle: Comparative Analysis of Medial Knee Collapse Definitions in Female Athletes

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Taylor Oldfather ◽  
Michael Zabala ◽  
Michael Goodlett ◽  
William (Hank) Murrah
Keyword(s):  
Injury Risk ◽  
Female Athletes ◽  
Cruciate Ligament ◽  
Three Dimensional ◽  
Reference Plane ◽  
Abduction Angle ◽  
Knee Valgus ◽  
Acl Injuries ◽  
Valgus Angle ◽  
Anterior Cruciate

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 << 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.

Do Mound Height and Pitching Distance Affect Youth Baseball Pitching Biomechanics?

2018 ◽  
Vol 46 (12) ◽  
pp. 2996-3001 ◽  
Author(s):  
Glenn S. Fleisig ◽  
Alek Z. Diffendaffer ◽  
Brett Ivey ◽  
Takanori Oi
Keyword(s):  
Analysis Of Variance ◽  
Repeated Measures ◽  
Injury Risk ◽  
Random Order ◽  
Kinematic Parameters ◽  
Joint Stress ◽  
Repeated Measures Analysis ◽  
Youth Baseball ◽  
Ball Velocity ◽  
Post Hoc

Background: Pitching injuries continue to be a serious problem, with adolescents now representing the group with the most injuries. Some have proposed that lowering or eliminating the pitching mound in youth baseball may reduce joint stress and subsequent injuries. Another potential risk factor is advancing from youth to adult pitching distance without an intermediate distance. Hypotheses: It was hypothesized that for a group of young pitchers, pitching kinetics and kinematics would change with mound height. It was also hypothesized that pitching kinetics and kinematics would change with pitching distance. Study Design: Controlled laboratory study. Methods: Twenty-one young (12.6 ± 0.5 years) baseball pitchers pitched 5 full-effort fastballs each from 5 different conditions, in random order: 14.02-, 16.46-, and 18.44-m distances from a 25 cm–high mound, 16.46-m distance from a 15 cm–high mound, and 16.46-m distance from flat ground. Pitching biomechanical values were collected with a 12-camera automated motion capture system. Ball velocity and 31 other parameters were computed for each pitch. Data were compared between the 3 mound heights at 16.46 m by use of repeated-measures analysis of variance and paired post hoc t tests ( P < .05). Similarly, data were compared between the 3 distances from the 25-cm mound via repeated-measures analysis of variance and paired post hoc t tests ( P < .05). Results: No differences were found in ball velocity, shoulder kinetics, or elbow kinetics associated with mound height. Ten kinematic parameters differed with mound height, including 8 parameters at lead foot contact. Maximum shoulder horizontal adduction torque and maximum shoulder anterior force increased with pitching distance. Only 3 kinematic parameters showed significant differences with pitching distance. Conclusion: The hypothesis that shoulder and elbow kinetics would change with mound height was not supported by the data. Several kinematic differences were found, but the majority were at lead foot contact before the rapid, dynamic phases of pitching. Change in pitching distance was associated with slight increase in shoulder kinetics as well as a few kinematic differences. Clinical Relevance: Lowering or eliminating pitching mounds in youth baseball would not significantly decrease joint stress and injury risk to young pitchers. However, when available, transition from 14.02-m to 16.46-m to 18.44-m pitching distance may reduce stress on the young throwing shoulder.

scholarly journals Are there sex differences in physiological parameters and reaction time responses to overload in firefighters?

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0249559
Author(s):  
Fabrizio Perroni ◽  
Ludovica Cardinali ◽  
Lamberto Cignitti ◽  
Erica Gobbi ◽  
Federico Grugni ◽  
...  
Keyword(s):  
Reaction Time ◽  
Repeated Measures ◽  
Injury Risk ◽  
Reaction Time Data ◽  
Work Capacity ◽  
Step Test ◽  
Time Data ◽  
Males And Females ◽  
Time Variables ◽  
Post Hoc

Male and female firefighters work side-by-side in the same in strenuous and risky conditions. Anthropometrics, physiological, and reaction time (mean of reaction time -MRT-, and errors made -E) parameters of 12 Female and 13 Male firefighters were compared. Effect of overload (step test with and without equipment) on the MRT and E were analyzed on 3 trials (T1 = 1-1s, T2 = 0.5-1s, T3 = 0.5–0.5s), compared with a pre-test condition (basal). T-test between males and females was applied to assess differences (p<0.05) in all parameters. ANOVA with repeated measures and Bonferroni on 3 conditions of step test between males and females was applied in reaction time variables. Between MRT and E, in T1, T2 and T3 trials and the 3 test conditions, ANCOVA models with interactions were used. Differences (p<0.05) in anthropometric, physiological and reaction time data emerged across groups, and on the 3rd trials (T3 vs T1 and T2) in reaction time parameters of each group. ANCOVA showed differences (p<0.001) in E among trials. Post hoc showed significant differences in T1vsT3 and T1vsT2. MRT x trial interaction was extremely significant (P<0.001). Implementing fitness and reaction time exercise programs is important to decrease the injury risk and increase work capacity in firefighters with reference to female workers.

scholarly journals Effect of Sex on Anterior Cruciate Ligament Injury–Related Biomechanics During the Cutting Maneuver in Preadolescent Athletes

2020 ◽  
Vol 8 (7) ◽  
pp. 232596712093698
Author(s):  
Milos Petrovic ◽  
Haraldur B. Sigurðsson ◽  
Hjálmar J. Sigurðsson ◽  
Thorarinn Sveinsson ◽  
Kristín Briem
Keyword(s):  
Injury Risk ◽  
Cruciate Ligament ◽  
Movement Patterns ◽  
Knee Valgus ◽  
Peak Knee ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Anterior Cruciate ◽  
Vertical Ground Reaction Forces ◽  
Biomechanical Factors

Background: There are 2 movement patterns associated with an anterior cruciate ligament (ACL) injury: dynamic valgus and stiff landing. Although sex-dependent differences have been identified for adults, less is known for preadolescent athletes regarding movement patterns known to load the ACL. Hypothesis: We hypothesized that girls would demonstrate greater vertical ground reaction forces and knee valgus angles. We further hypothesized that the exercise intervention would affect girls more than boys and that this would primarily be demonstrated in less sagittal plane excursions, increased vertical ground reaction forces and knee valgus moments for girls than for boys. Study Design: Controlled laboratory study. Methods: Male and female soccer and handball players (n = 288; age range, 9-12 years) were recruited. A motion capture system synchronized to a force platform was used to record 5 trials of a cutting maneuver before and after a 5-minute fatigue intervention. Linear mixed models were constructed, and analysis of variance was used to analyze differences in outcomes associated with the sex of the athletes. Results: Boys showed greater peak knee valgus moment (0.26 vs 0.22 N·m/kg, respectively; P = .048), peak knee internal rotation moment (–0.13 vs –0.10 N·m/kg, respectively; P = .021), knee rotation excursion (–7.9° vs –6.9°, respectively; P = .014), and knee extension excursion (2.7° vs 1.4°, respectively; P < .001) compared with that in girls. A significant sex × fatigue intervention interaction ( F = 7.6; P = .006) was found, which was caused by a greater increase in first peak vertical ground-reaction force (vGRF) from before to after the fatigue intervention for girls (15.3 to 16.0 N/kg) compared with boys (16.4 to 16.5 N/kg). Conclusion: Differences detected for biomechanical factors during the cutting maneuver do not point to a greater ACL injury risk for prepubescent or early pubescent girls than for boys. Nonetheless, girls go on to develop more detrimental movement patterns in adolescence than those in boys in terms of biomechanical risk factors. Clinical Relevance: Early adolescence is a good target age to learn and develop muscular control; balance, strength; flexibility; and jumping, running, and landing control. This time of physical and athletic growth may therefore be an appropriate period to influence biomechanical factors and thereby task execution and the injury risk.

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