Knee abduction moment (KAM) is an injury risk factor for ACL injury that shows divergent incidenc... more Knee abduction moment (KAM) is an injury risk factor for ACL injury that shows divergent incidence between males and females during adolescence. Objectives of this study were to determine the relationship between skeletal growth and increased KAM. The hypotheses tested were that females would demonstrate peak KAM during landing at peak height velocity (PHV) and they would diverge from males at PHV. The subject pool consisted of 674 females and 218 males (1387 female; 376 male assessments) who participated in a pre-season testing session prior to their basketball or soccer seasons. They were tested longitudinally for multiple years (2±1) to capture maturation via estimates of percent (%) adult stature and biomechanical analysis during a drop vertical jump maneuver. Data were analyzed using 3D motion analysis that employed a 37 retro-reflective marker body model and inverse dynamics to calculate segment joint centers and peak KAM. Mature females, as defined as 92% adult stature or greater, displayed increased peak KAM and knee abduction angles (KAA) relative to growing (≤91% adult stature) adolescent females (p < 0.001). A significant sex by maturation (% adult stature) interaction (p < 0.001) in peak KAM was observed. Post-hoc analyses showed consistent sex differences in groups greater than or equal to, but not less than, 92% adult stature, which is approximately at peak height velocity. Hence, sex differences in peak KAM and PHV coincide. Increases in peak KAM during and following PHV appear to coincide with increased risk of ACL injury in females. KAM peaked in females at PHV. Tracking longitudinal increases in peak KAM may be useful for the identification of females at increased risk of ACL injury.This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially.
Ballet dancers have heightened balance skills, but previous studies that compared dancers to non-... more Ballet dancers have heightened balance skills, but previous studies that compared dancers to non-dancers have not quantified patterns of multi-joint postural coordination. This study utilized a visual tracking task that required professional ballet dancers and untrained control participants to sway with the fore–aft motion of a target while standing on one leg, at target frequencies of 0.2 and 0.6 Hz. The mean and variability of relative phase between the ankle and hip, and measures from cross-recurrence quantification analysis (i.e., percent cross-recurrence, percent cross-determinism, and cross-maxline), indexed the coordination patterns and their stability. Dancers exhibited less variable ankle–hip coordination and a less deterministic ankle–hip coupling, compared to controls. The results indicate that ballet dancers have increased coordination stability, potentially achieved through enhanced neuromuscular control and/or perceptual sensitivity, and indicate proficiency at optimizing the constraints that enable dancers to perform complex balance tasks.
Tropomyosin (TM) is an integral component of the thin filament in muscle fibers and is involved i... more Tropomyosin (TM) is an integral component of the thin filament in muscle fibers and is involved in regulating actin-myosin interactions. TM is encoded by a family of four alternatively spliced genes that display highly conserved nucleotide and amino acid sequences. To assess the functional and developmental significance of a-TM, the murine a-TM gene was disrupted by homologous recombination. Homozygous a-TM
Background: Anterior cruciate ligament (ACL) injury is a devastating injury that puts an athlete ... more Background: Anterior cruciate ligament (ACL) injury is a devastating injury that puts an athlete at high risk of future osteoarthritis. Identification of risk factors and development of ACL prevention programmes likely decrease injury risk.
Although intrinsic and extrinsic risk factors for anterior cruciate ligament (ACL) injury have be... more Although intrinsic and extrinsic risk factors for anterior cruciate ligament (ACL) injury have been explored extensively, the factors surrounding the inciting event and the biomechanical mechanisms underlying ACL injury remain elusive. This systematic review summarizes all the relevant data and clarifies the strengths and weaknesses of the literature regarding ACL injury mechanisms. The hypothesis is that most ACL injuries do not occur via solely sagittal, frontal or transverse plane mechanisms. Electronic database literature searches of PubMed MEDLINE (1966-2008), CINAHL (1982-2008) and SportDiscus (1985-2008) were used for the systematic review to identify any studies in the literature that examined ACL injury mechanisms. Methodological approaches that describe and evaluate ACL injury mechanisms included athlete interviews, arthroscopic studies, clinical imaging and physical exam tests, video analysis, cadaveric studies, laboratory tests (motion analysis, electromyography) and mathematical modelling studies. One hundred and ninety-eight studies associated with ACL injury mechanisms were identified and provided evidence regarding plane of injury, with evidence supporting sagittal, frontal and/or transverse plane mechanisms of injury. Collectively, the studies indicate that it is highly probable that ACL injuries are more likely to occur during multi-planar rather than single-planar mechanisms of injury.
Female athletes who participate in jumping and cutting sports are 4 to 6 times more likely to sus... more Female athletes who participate in jumping and cutting sports are 4 to 6 times more likely to sustain a serious knee injury than male athletes participating in the same sports. More than 30,000 serious knee injuries are projected to occur in female intercollegiate and high school athletics in the US each year. The majority of these injuries occur by non-contact mechanisms, most often during landing from a jump or making a lateral pivot while running. Knee instability, due possibly to decreased neuromuscular strength and coordination or increased ligamentous laxity, may underlie the increased incidence of knee injury in females. Neuromuscular training can significantly increase dynamic knee stability in female athletes. Female sex hormones (i.e. estrogen, progesterone and relaxin) fluctuate radically during the menstrual cycle and are reported to increase ligamentous laxity and decrease neuromuscular performance and, thus, are a possible cause of decreases in both passive and active knee stability in female athletes. Oral contraceptives stabilise hormone levels during the menstrual cycle and may function to either passively or actively stabilise the knee joint. The long term objective of clinicians and researchers should be to determine the factors that make women more susceptible than men to knee ligament injury and to develop treatment modalities to aid in the prevention of these injuries. The immediate objectives of this review are to examine how female and male athletes differ in neuromuscular and ligamentous control of the lower extremity. The review will examine the effects of neuromuscular training on knee stability. The effects of female hormone levels and oral contraceptives on neuromuscular control of the female athletes' knee will also be discussed.
Scandinavian Journal of Medicine and Science in Sports, 2004
initiated a program design that focused on correction of dynamic movement patterns and muscle imb... more initiated a program design that focused on correction of dynamic movement patterns and muscle imbalances that utilized technique training and lower body plyometrics with supplemental Scand
There is growing interest in the effects of psychological states on human performance, especially... more There is growing interest in the effects of psychological states on human performance, especially with those who have suffered debilitating injury and are attempting to return to sport (RTS). Current research methods measure psychological states through validated questionnaires; however, these outcomes only allow for subjective assessment and may be unintentionally biased. Application of objective neurocognitive measures correlated with psychological states will advance understanding of injury outcomes by identifying human behavior and avoiding vague assumptions from subjective measures.
Anterior cruciate ligament (ACL) injuries are common, catastrophic events that incur large expens... more Anterior cruciate ligament (ACL) injuries are common, catastrophic events that incur large expense and lead to degradation of the knee. As such, various motion capture techniques have been applied to identify athletes who are at increased risk for suffering ACL injuries. The objective of this clinical commentary was to synthesize information related to how motion capture analyses contribute to the identification of risk factors that may predict relative injury risk within a population. Individuals employ both active and passive mechanisms to constrain knee joint articulation during motion. There is strong evidence to indicate that athletes who consistently classify as high-risk loaders during landing suffer from combined joint stability deficits in both the active and passive knee restraints. Implementation of prophylactic neuromuscular interventions and biofeedback can effectively compensate for some of the deficiencies that result from poor control of the active knee stabilizers and reduce the incidence of ACL injuries.
Brazilian journal of physical therapy, Jan 6, 2015
Our biodynamics laboratory group has conducted large cohort biomechanical-epidemiological studies... more Our biodynamics laboratory group has conducted large cohort biomechanical-epidemiological studies targeted at identifying the complex interactions among biomechanical, biological, hormonal, and psychosocial factors that lead to increased risk of anterior cruciate ligament (ACL) injuries. The findings from our studies have revealed highly sensitive and specific predictors for ACL injury. Despite the high incidence of ACL injuries among young athletes, larger cohorts are needed to reveal the underlying mechanistic causes of increased risk for ACL injury. In the current study, we have outlined key factors that contribute to the overall success of multicenter, biomechanical-epidemiological investigations designed to test a larger number of athletes who otherwise could not be recruited, screened, or tested at a single institution. Twenty-five female volleyball players were recruited from a single high school team and tested at three biodynamics laboratories. All athletes underwent three-...
The objective of this study was to determine whether biomechanical and neuromuscular risk factors... more The objective of this study was to determine whether biomechanical and neuromuscular risk factors related to abnormal movement patterns increased in females, but not males, during the adolescent growth spurt. A total of 315 subjects participated in two testing sessions approximately 1 yr apart. Male and female subjects were classified on the basis of their maturation status as pubertal or postpubertal. Three trials of a drop vertical jump (DVJ) were collected. Maximum knee abduction angle and external moments were calculated during the DVJ deceleration phase using a three-dimensional motion analysis system. Changes in knee abduction from the first to second year were compared among four subject groups (female pubertal, female postpubertal, male pubertal, and male postpubertal). There were no sex differences in peak knee abduction angle or moment during DVJ between pubertal males and females (P > 0.05). However, pubertal females increased peak abduction angle from first to second year (P < 0.001), whereas males demonstrated no similar change (P = 0.90) in the matched developmental stages. After puberty, the peak abduction angle and moment were greater in females relative to males (angle: female -9.3° ± 5.7°, male -3.6° ± 4.6°, P < 0.001; moment: female -21.9 ± 13.5 N·m, male -13.0 ± 12.0 N·m, P = 0.017). This study identified, through longitudinal analyses, that knee abduction angle was significantly increased in pubertal females during rapid adolescent growth, whereas males showed no similar change. In addition, knee abduction motion and moments were significantly greater for the subsequent year in young female athletes, after rapid adolescent growth, compared with males. The combination of longitudinal, sex, and maturational group differences indicates that early puberty seems to be a critical phase related to the divergence of increased anterior cruciate ligament injury risk factors.
The purpose of this study was to utilize three-dimensional kinematic (motion) analysis to determi... more The purpose of this study was to utilize three-dimensional kinematic (motion) analysis to determine whether gender differences existed in knee valgus kinematics in high school basketball athletes when performing a landing maneuver. The hypothesis of this study was that female athletes would demonstrate greater valgus knee motion (ligament dominance) and greater side-to-side (leg dominance) differences in valgus knee angle at landing. These differences in valgus knee motion may be indicative of decreased dynamic knee joint control in female athletes. Eighty-one high school basketball players, 47 female and 34 male, volunteered to participate in this study. Valgus knee motion and varus-valgus angles during a drop vertical jump (DVJ) were calculated for each subject. The DVJ maneuver consisted of dropping off of a box, landing and immediately performing a maximum vertical jump. The first landing phase was used for the analysis. Female athletes landed with greater total valgus knee motion and a greater maximum valgus knee angle than male athletes. Female athletes had significant differences between their dominant and nondominant side in maximum valgus knee angle. The absence of dynamic knee joint stability may be responsible for increased rates of knee injury in females but is not normally measured in athletes before participation. No method for accurate and practical screening and identification of athletes at increased risk of ACL injury is currently available to target those individuals that would benefit from neuromuscular training before sports participation. Prevention of female ACL injury from five times to equal the rate of males would allow tens of thousands of young females to avoid the potentially devastating effects of ACL injury on their athletic careers.
Biomechanical measures quantified during dynamic tasks with coupled epidemiological data in longi... more Biomechanical measures quantified during dynamic tasks with coupled epidemiological data in longitudinal experimental designs may be useful to determine which mechanisms underlie injury risk in young athletes. A key component is the ability to reliably measure biomechanical variables between testing sessions. The purpose was to determine the reliability of three-dimensional (3D) lower-extremity kinematic and kinetic variables during landing in young athletes measured within a session and between two sessions 7 wk apart. Lower-extremity kinetics and kinematics were quantified during a drop vertical jump. Coefficient of multiple correlations (CMC), intraclass correlation coefficients (ICC (3, k), ICC (3, 1)), and typical error (TE) analyses were used to examine within- and between-session reliability. There were no differences in within-session reliability for peak angular rotations between planes with all discrete variables combined (sagittal ICC > or = 0.933, frontal ICC > or = 0.955, transverse ICC > or = 0.934). Similarly, the between-session reliability of kinematic measures were not different between the three planes of motion but were lower than the within-session ICC. The within- and between-session reliability of discrete joint moment variables were excellent for all sagittal (within ICC > or = 0.925, between ICC > or = 0.800) and frontal plane moment measures (within ICC > or = 0.778, between ICC > or = 0.748). CMC analysis revealed similar averaged within-session (CMC = 0.830 +/- 0.119) and between-session (CMC = 0.823 +/- 0.124) waveform comparisons. The majority of the kinematic and kinetic variables in young athletes during landing have excellent to good reliability. The ability to reliably quantify lower-extremity biomechanical variables of young athletes during dynamic tasks over extended intervals may aid in identifying potential mechanisms related to injury risk factors.
Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Medicine &amp... more Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Medicine & Science in Sports & Exercise. Enter your Email address: Wolters Kluwer Health may email you for journal alerts and information, but ...
Knee abduction moment (KAM) is an injury risk factor for ACL injury that shows divergent incidenc... more Knee abduction moment (KAM) is an injury risk factor for ACL injury that shows divergent incidence between males and females during adolescence. Objectives of this study were to determine the relationship between skeletal growth and increased KAM. The hypotheses tested were that females would demonstrate peak KAM during landing at peak height velocity (PHV) and they would diverge from males at PHV. The subject pool consisted of 674 females and 218 males (1387 female; 376 male assessments) who participated in a pre-season testing session prior to their basketball or soccer seasons. They were tested longitudinally for multiple years (2±1) to capture maturation via estimates of percent (%) adult stature and biomechanical analysis during a drop vertical jump maneuver. Data were analyzed using 3D motion analysis that employed a 37 retro-reflective marker body model and inverse dynamics to calculate segment joint centers and peak KAM. Mature females, as defined as 92% adult stature or greater, displayed increased peak KAM and knee abduction angles (KAA) relative to growing (≤91% adult stature) adolescent females (p < 0.001). A significant sex by maturation (% adult stature) interaction (p < 0.001) in peak KAM was observed. Post-hoc analyses showed consistent sex differences in groups greater than or equal to, but not less than, 92% adult stature, which is approximately at peak height velocity. Hence, sex differences in peak KAM and PHV coincide. Increases in peak KAM during and following PHV appear to coincide with increased risk of ACL injury in females. KAM peaked in females at PHV. Tracking longitudinal increases in peak KAM may be useful for the identification of females at increased risk of ACL injury.This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially.
Ballet dancers have heightened balance skills, but previous studies that compared dancers to non-... more Ballet dancers have heightened balance skills, but previous studies that compared dancers to non-dancers have not quantified patterns of multi-joint postural coordination. This study utilized a visual tracking task that required professional ballet dancers and untrained control participants to sway with the fore–aft motion of a target while standing on one leg, at target frequencies of 0.2 and 0.6 Hz. The mean and variability of relative phase between the ankle and hip, and measures from cross-recurrence quantification analysis (i.e., percent cross-recurrence, percent cross-determinism, and cross-maxline), indexed the coordination patterns and their stability. Dancers exhibited less variable ankle–hip coordination and a less deterministic ankle–hip coupling, compared to controls. The results indicate that ballet dancers have increased coordination stability, potentially achieved through enhanced neuromuscular control and/or perceptual sensitivity, and indicate proficiency at optimizing the constraints that enable dancers to perform complex balance tasks.
Tropomyosin (TM) is an integral component of the thin filament in muscle fibers and is involved i... more Tropomyosin (TM) is an integral component of the thin filament in muscle fibers and is involved in regulating actin-myosin interactions. TM is encoded by a family of four alternatively spliced genes that display highly conserved nucleotide and amino acid sequences. To assess the functional and developmental significance of a-TM, the murine a-TM gene was disrupted by homologous recombination. Homozygous a-TM
Background: Anterior cruciate ligament (ACL) injury is a devastating injury that puts an athlete ... more Background: Anterior cruciate ligament (ACL) injury is a devastating injury that puts an athlete at high risk of future osteoarthritis. Identification of risk factors and development of ACL prevention programmes likely decrease injury risk.
Although intrinsic and extrinsic risk factors for anterior cruciate ligament (ACL) injury have be... more Although intrinsic and extrinsic risk factors for anterior cruciate ligament (ACL) injury have been explored extensively, the factors surrounding the inciting event and the biomechanical mechanisms underlying ACL injury remain elusive. This systematic review summarizes all the relevant data and clarifies the strengths and weaknesses of the literature regarding ACL injury mechanisms. The hypothesis is that most ACL injuries do not occur via solely sagittal, frontal or transverse plane mechanisms. Electronic database literature searches of PubMed MEDLINE (1966-2008), CINAHL (1982-2008) and SportDiscus (1985-2008) were used for the systematic review to identify any studies in the literature that examined ACL injury mechanisms. Methodological approaches that describe and evaluate ACL injury mechanisms included athlete interviews, arthroscopic studies, clinical imaging and physical exam tests, video analysis, cadaveric studies, laboratory tests (motion analysis, electromyography) and mathematical modelling studies. One hundred and ninety-eight studies associated with ACL injury mechanisms were identified and provided evidence regarding plane of injury, with evidence supporting sagittal, frontal and/or transverse plane mechanisms of injury. Collectively, the studies indicate that it is highly probable that ACL injuries are more likely to occur during multi-planar rather than single-planar mechanisms of injury.
Female athletes who participate in jumping and cutting sports are 4 to 6 times more likely to sus... more Female athletes who participate in jumping and cutting sports are 4 to 6 times more likely to sustain a serious knee injury than male athletes participating in the same sports. More than 30,000 serious knee injuries are projected to occur in female intercollegiate and high school athletics in the US each year. The majority of these injuries occur by non-contact mechanisms, most often during landing from a jump or making a lateral pivot while running. Knee instability, due possibly to decreased neuromuscular strength and coordination or increased ligamentous laxity, may underlie the increased incidence of knee injury in females. Neuromuscular training can significantly increase dynamic knee stability in female athletes. Female sex hormones (i.e. estrogen, progesterone and relaxin) fluctuate radically during the menstrual cycle and are reported to increase ligamentous laxity and decrease neuromuscular performance and, thus, are a possible cause of decreases in both passive and active knee stability in female athletes. Oral contraceptives stabilise hormone levels during the menstrual cycle and may function to either passively or actively stabilise the knee joint. The long term objective of clinicians and researchers should be to determine the factors that make women more susceptible than men to knee ligament injury and to develop treatment modalities to aid in the prevention of these injuries. The immediate objectives of this review are to examine how female and male athletes differ in neuromuscular and ligamentous control of the lower extremity. The review will examine the effects of neuromuscular training on knee stability. The effects of female hormone levels and oral contraceptives on neuromuscular control of the female athletes' knee will also be discussed.
Scandinavian Journal of Medicine and Science in Sports, 2004
initiated a program design that focused on correction of dynamic movement patterns and muscle imb... more initiated a program design that focused on correction of dynamic movement patterns and muscle imbalances that utilized technique training and lower body plyometrics with supplemental Scand
There is growing interest in the effects of psychological states on human performance, especially... more There is growing interest in the effects of psychological states on human performance, especially with those who have suffered debilitating injury and are attempting to return to sport (RTS). Current research methods measure psychological states through validated questionnaires; however, these outcomes only allow for subjective assessment and may be unintentionally biased. Application of objective neurocognitive measures correlated with psychological states will advance understanding of injury outcomes by identifying human behavior and avoiding vague assumptions from subjective measures.
Anterior cruciate ligament (ACL) injuries are common, catastrophic events that incur large expens... more Anterior cruciate ligament (ACL) injuries are common, catastrophic events that incur large expense and lead to degradation of the knee. As such, various motion capture techniques have been applied to identify athletes who are at increased risk for suffering ACL injuries. The objective of this clinical commentary was to synthesize information related to how motion capture analyses contribute to the identification of risk factors that may predict relative injury risk within a population. Individuals employ both active and passive mechanisms to constrain knee joint articulation during motion. There is strong evidence to indicate that athletes who consistently classify as high-risk loaders during landing suffer from combined joint stability deficits in both the active and passive knee restraints. Implementation of prophylactic neuromuscular interventions and biofeedback can effectively compensate for some of the deficiencies that result from poor control of the active knee stabilizers and reduce the incidence of ACL injuries.
Brazilian journal of physical therapy, Jan 6, 2015
Our biodynamics laboratory group has conducted large cohort biomechanical-epidemiological studies... more Our biodynamics laboratory group has conducted large cohort biomechanical-epidemiological studies targeted at identifying the complex interactions among biomechanical, biological, hormonal, and psychosocial factors that lead to increased risk of anterior cruciate ligament (ACL) injuries. The findings from our studies have revealed highly sensitive and specific predictors for ACL injury. Despite the high incidence of ACL injuries among young athletes, larger cohorts are needed to reveal the underlying mechanistic causes of increased risk for ACL injury. In the current study, we have outlined key factors that contribute to the overall success of multicenter, biomechanical-epidemiological investigations designed to test a larger number of athletes who otherwise could not be recruited, screened, or tested at a single institution. Twenty-five female volleyball players were recruited from a single high school team and tested at three biodynamics laboratories. All athletes underwent three-...
The objective of this study was to determine whether biomechanical and neuromuscular risk factors... more The objective of this study was to determine whether biomechanical and neuromuscular risk factors related to abnormal movement patterns increased in females, but not males, during the adolescent growth spurt. A total of 315 subjects participated in two testing sessions approximately 1 yr apart. Male and female subjects were classified on the basis of their maturation status as pubertal or postpubertal. Three trials of a drop vertical jump (DVJ) were collected. Maximum knee abduction angle and external moments were calculated during the DVJ deceleration phase using a three-dimensional motion analysis system. Changes in knee abduction from the first to second year were compared among four subject groups (female pubertal, female postpubertal, male pubertal, and male postpubertal). There were no sex differences in peak knee abduction angle or moment during DVJ between pubertal males and females (P > 0.05). However, pubertal females increased peak abduction angle from first to second year (P < 0.001), whereas males demonstrated no similar change (P = 0.90) in the matched developmental stages. After puberty, the peak abduction angle and moment were greater in females relative to males (angle: female -9.3° ± 5.7°, male -3.6° ± 4.6°, P < 0.001; moment: female -21.9 ± 13.5 N·m, male -13.0 ± 12.0 N·m, P = 0.017). This study identified, through longitudinal analyses, that knee abduction angle was significantly increased in pubertal females during rapid adolescent growth, whereas males showed no similar change. In addition, knee abduction motion and moments were significantly greater for the subsequent year in young female athletes, after rapid adolescent growth, compared with males. The combination of longitudinal, sex, and maturational group differences indicates that early puberty seems to be a critical phase related to the divergence of increased anterior cruciate ligament injury risk factors.
The purpose of this study was to utilize three-dimensional kinematic (motion) analysis to determi... more The purpose of this study was to utilize three-dimensional kinematic (motion) analysis to determine whether gender differences existed in knee valgus kinematics in high school basketball athletes when performing a landing maneuver. The hypothesis of this study was that female athletes would demonstrate greater valgus knee motion (ligament dominance) and greater side-to-side (leg dominance) differences in valgus knee angle at landing. These differences in valgus knee motion may be indicative of decreased dynamic knee joint control in female athletes. Eighty-one high school basketball players, 47 female and 34 male, volunteered to participate in this study. Valgus knee motion and varus-valgus angles during a drop vertical jump (DVJ) were calculated for each subject. The DVJ maneuver consisted of dropping off of a box, landing and immediately performing a maximum vertical jump. The first landing phase was used for the analysis. Female athletes landed with greater total valgus knee motion and a greater maximum valgus knee angle than male athletes. Female athletes had significant differences between their dominant and nondominant side in maximum valgus knee angle. The absence of dynamic knee joint stability may be responsible for increased rates of knee injury in females but is not normally measured in athletes before participation. No method for accurate and practical screening and identification of athletes at increased risk of ACL injury is currently available to target those individuals that would benefit from neuromuscular training before sports participation. Prevention of female ACL injury from five times to equal the rate of males would allow tens of thousands of young females to avoid the potentially devastating effects of ACL injury on their athletic careers.
Biomechanical measures quantified during dynamic tasks with coupled epidemiological data in longi... more Biomechanical measures quantified during dynamic tasks with coupled epidemiological data in longitudinal experimental designs may be useful to determine which mechanisms underlie injury risk in young athletes. A key component is the ability to reliably measure biomechanical variables between testing sessions. The purpose was to determine the reliability of three-dimensional (3D) lower-extremity kinematic and kinetic variables during landing in young athletes measured within a session and between two sessions 7 wk apart. Lower-extremity kinetics and kinematics were quantified during a drop vertical jump. Coefficient of multiple correlations (CMC), intraclass correlation coefficients (ICC (3, k), ICC (3, 1)), and typical error (TE) analyses were used to examine within- and between-session reliability. There were no differences in within-session reliability for peak angular rotations between planes with all discrete variables combined (sagittal ICC > or = 0.933, frontal ICC > or = 0.955, transverse ICC > or = 0.934). Similarly, the between-session reliability of kinematic measures were not different between the three planes of motion but were lower than the within-session ICC. The within- and between-session reliability of discrete joint moment variables were excellent for all sagittal (within ICC > or = 0.925, between ICC > or = 0.800) and frontal plane moment measures (within ICC > or = 0.778, between ICC > or = 0.748). CMC analysis revealed similar averaged within-session (CMC = 0.830 +/- 0.119) and between-session (CMC = 0.823 +/- 0.124) waveform comparisons. The majority of the kinematic and kinetic variables in young athletes during landing have excellent to good reliability. The ability to reliably quantify lower-extremity biomechanical variables of young athletes during dynamic tasks over extended intervals may aid in identifying potential mechanisms related to injury risk factors.
Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Medicine &amp... more Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Medicine & Science in Sports & Exercise. Enter your Email address: Wolters Kluwer Health may email you for journal alerts and information, but ...
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