Background. Anterior cruciate ligament (ACL) deficiency can be a major problem for athletes and s... more Background. Anterior cruciate ligament (ACL) deficiency can be a major problem for athletes and subsequent reconstruction of the ACL may be indicated if a conservative regimen has failed. After ACL reconstruction signs of abnormality in the use of the leg remain for a long time. It is expected that the landing after a single-leg hop for distance (horizontal hop) might give insight in the differences in kinematics and kinetics between uninjured legs and ACL-reconstructed legs. Before the ACL-reconstructed leg can be compared with the contralateral leg, knowledge of differences between legs of uninjured subjects is needed.
ABSTRACT Neuropsychological capabilities in athletes may be associated with a predisposition to a... more ABSTRACT Neuropsychological capabilities in athletes may be associated with a predisposition to anterior cruciate ligament (ACL) injuries. Assess differences between male and female athletes in jump-landing technique in relation to their neuropsychological capabilities. Experimental. Laboratory. 31 recreational athletes, free from lower extremity injuries, participated (females: n=16, age=21.0±1.71 years, mass=65.1±5.6 kg, height=174.2±68.9 cm; males n=15, age=22.3±2.2 years, mass=77.9±8.9 kg, height=185.7±78.7 cm). Reaction time (RT) under stress was measured. Furthermore, participants conducted anticipated (ANT) and unanticipated (UNANT) double-legged drop-jumps, followed by running at 4.5-5.5 m/sec 45° to the left, straight, or 45° to the right, depending on the light indication prior to landing on the force plates. RT and joint kinematics (trunk flexion-TF, ankle flexion-AF) and kinetics (knee abduction moment-KAM, ankle extension moment-AEM) at peak vertical ground reaction force (vGRF,N/kg). Moments are expressed as external moments (Nm/kg). Pearson product-moment correlation between RT and joint biomechanics. During UNANT, KAM became significantly larger (P=.010) in females (-0.37±0.1) than males (-0.16±0.1). TF was greater in the AT (29.7°±3.3°) than UNANT (46.1°±3.1°) regardless of gender (P<001). AEM was smaller in females (2.1±0.1) than males (2.6±0.1), (P=.001). AF was smaller (i.e., increased flexion) when running straight (80.8°±0.8°) compared to the left or right (84.6°±0.7°, P=.002 and 84.2°±0.8°, P=.008). vGRF was smaller when running straight (22.8±1.0) compared to the left or right (31.5±1.0, P<.001 and 28.8±1.0, P<.001). Significant correlations (r 0.5-0.8, P<.05) were seen between faster RT and greater hip and knee flexion angle and smaller KAM and knee abduction angle. Females reacted differently to UNANT in the frontal plane, potentially placing them at greater ACL injury risk. In the sagittal plane, females showed stiffer ankle landing. Further, a change in direction increased vGRF. Smaller knee flexion combined with smaller TF angles during UNANT, may increase loads at the knee. Lastly, neuropsychological characteristics seem to affect ACL injury risk.
External focus instructions have been shown to result in superior motor performance compared to i... more External focus instructions have been shown to result in superior motor performance compared to internal focus instructions. Using an EF may help to optimize current anterior cruciate ligament (ACL) injury prevention programs. The purpose of the current study was to investigate the effects of instructions on landing technique and performance by comparing an external focus (EF), internal focus (IF), video (VI) and control (CTRL) group. Subjects (age 22.50±1.62years, height 179.70±10.43cm, mass 73.98±12.68kg) were randomly assigned to IF (n=10), EF (n=10), VI (n=10) or CTRL group (n=10). Landing was assessed from a drop vertical jump (DVJ) in five sessions: pretest, two training blocks (TR1 and TR2) and directly after the training sessions (post test) and retention test 1week later. Group specific instructions were offered in TR1 and TR2. Landing technique was assessed with the Landing Error Scoring System (LESS) and jump height was taken as performance measure. The results show that ...
The purpose of this section is to present the general guidelines for rehabilitating an injured te... more The purpose of this section is to present the general guidelines for rehabilitating an injured tennis player. The focus is on treating the most common injury pattern of overhead athletes, ie, rotator cuff pathology with secondary bursitis and finally microtraumatic instability. The ...
This contribution presents an overview on the development of knee rehabilitation as considered fr... more This contribution presents an overview on the development of knee rehabilitation as considered from the training science and sensomotorics point-of-view. The first part deals with the development of modern, medical training therapy and its relation to training science. The increasing significance of quality management is pointed out. The second part of the contribution focuses on recent knowledge in sensomotorics and on still unanswered questions which will be of significance in coming years. With anterior cruciate injuries as an example, the patient is shown to reconstruct his own sensomotor system. It is shown that in future, in selecting the choice of clinical parameter, care must be taken to ensure they relate to function as a whole – in the given case, to gait.
The aims of the study were (1) to evaluate the leg asymmetry assessed with ground reaction forces... more The aims of the study were (1) to evaluate the leg asymmetry assessed with ground reaction forces (GRFs) during unilateral and bilateral movements of different knee loads in anterior cruciate ligament (ACL) reconstructed patients and (2) to investigate differences in leg asymmetry depending on the International Knee Documentation Committee Subjective Form (IKDC) in order to identify potential compensation strategies. The knee function of 50 ACL reconstructed (patella tendon) patients was examined at 31 ± 7 months after the surgery. GRFs were quantified during the sit-to-stand and stand-to-sit test, the step-up and step-down test, and the two- and one-leg vertical jump. Further, the IKDC score, the anterior-posterior knee laxity, and the concentric torque of the quadriceps and hamstring muscles were evaluated. Differences between the operated and non-operated leg were found in the knee laxity, the quadriceps torque, and GRFs. The patients with low IKDC scores demonstrated greater leg asymmetries in GRFs compared to the patients with high IKDC scores. ACL reconstructed patients showed GRF asymmetries during unilateral and bilateral movements of different knee loads. Three compensation strategies were found in patients with low subjective knee function: (1) a reduced eccentric load, (2) an inter-limb compensation during bilateral movements, and (3) the avoidance of high vertical impact forces. These compensation strategies may be indicative of a protective adaptation to avoid excessive ACL strain. GRF measurements are practicable and efficient tools to identify individual compensation strategies during early rehabilitation.
This study investigated exercise-induced effects of static stretching and playing soccer on anter... more This study investigated exercise-induced effects of static stretching and playing soccer on anterior tibial translation (ATT) of the knee joint. Randomized controlled trial. University biomechanics laboratory. Thirty-one athletes were randomly assigned into a stretching (26.9 ± 6.2 years, 1.77 ± 0.09 m, 67.9 ± 10.7 kg) and a control group (27.9 ± 7.4 years, 1.75 ± 0.08 m, 72.0 ± 14.9 kg). Thirty-one amateur soccer players in an additional soccer group (25.1 ± 5.6 years, 1.74 ± 0.10 m, 71.8 ± 14.8 kg). All participants had no history of knee injury requiring surgery and any previous knee ligament or cartilage injury. The stretching group performed 4 different static stretching exercises with a duration of 2 × 20 seconds interspersed with breaks of 10 seconds. The soccer group completed a 90-minute soccer-specific training program. The control group did not perform any physical activity for approximately 30 minutes. Anterior tibial translation was measured with the KT-1000 knee arthrometer at forces of 67 N, 89 N, and maximal manual force (Max) before and after the intervention. There was a significant increase in ATT after static stretching and playing soccer at all applied forces. Maximal manual testing revealed a mean increase of ATT after static stretching of 2.1 ± 1.6 mm (P < 0.0005) and after playing soccer of 1.0 ± 1.5 mm (P = 0.001). The ATT increase after static stretching at 67 and 89 N is significantly higher than in controls. At maximum manual testing, significant differences were evident between all groups. Static stretching and playing soccer increase ATT and may consequently influence mechanical factors of the anterior cruciate ligament. The ATT increase after static stretching was greater than after playing soccer. The observed increase in ATT after static stretching and playing soccer may be associated with changes in kinesthetic perception and sensorimotor control, activation of muscles, joint stability, overall performance, and higher injury risk.
Adding external focus of attention (EF, focus on the movement effect) may optimize current anteri... more Adding external focus of attention (EF, focus on the movement effect) may optimize current anterior cruciate ligament (ACL) injury prevention programmes. The purpose of the current study was to investigate the effects of an EF, by a visual stimulus and an internal focus, by a verbal stimulus during unexpected sidestep cutting in female and male athletes and how these effects remained over time. Ninety experienced basketball athletes performed sidestep cutting manoeuvres in three sessions (S1, S2 and S3). In this randomized controlled trial, athletes were allocated to three groups: visual (VIS), verbal (VER) and control (CTRL). Kinematics and kinetics were collected at the time of peak knee frontal plane moment. Males in the VIS group showed a larger vertical ground reaction force (S1: 25.4 ± 3.1 N/kg, S2: 25.8 ± 2.9 N/kg, S3: 25.2 ± 3.2 N/kg) and knee flexion moments (S1: -3.8 ± 0.9 Nm/kg, S2: -4.0 ± 1.2 Nm/kg, S3: -3.9 ± 1.3 Nm/kg) compared to the males in the VER and CTRL groups and to the females in the VIS group (p < 0.05). Additionally, the males in the VIS group reduced knee valgus moment and the females in the VER group reduced knee varus moment over time (n.s.). Male subjects clearly benefit from visual feedback. Females may need different feedback modes to learn a correct movement pattern. Sex-specific learning preferences may have to be acknowledged in day by day practice. Adding video instruction or feedback to regular training regimens when teaching athletes safe movement patterns and providing individual feedback might target suboptimal long-term results and optimize ACL injury prevention programmes. I.
ABSTRACT Anterior cruciate ligament (ACL) injury prevention programs have shown mixed results, wh... more ABSTRACT Anterior cruciate ligament (ACL) injury prevention programs have shown mixed results, which may be in part due to suboptimal training components. Determine effects of a prevention program with external and internal focus of attention on (potential) biomechanical risk factors for ACL injury. Pretest-posttest control group. Laboratory and field. 31 elite female soccer players participated. Exclusion criteria included previous ACL injury or current lower extremity injury. Two teams performed warm-up programs, including strength, agility, balance, plyometric, core and speed exercises twice a week for 12 weeks. One team received instructions to focus attention internally toward movements of the body (INT); another team received instructions to focus attention externally near the body (EXT). The control group (CON) performed their regular warming-up without specific instructions. Normalized external knee and ankle joint moments and joint angles on a two-legged jump-landing-rebound task. Results of 3x2 repeated measures ANOVA revealed significant group x time interaction for peak knee extension moment (F (2,23)=4.09, P=.03), the EXT group decreased more (-0.90±0.16 to -0.73±0.15 Nm/kg*m) than the CON group (P<.05). Regarding knee flexion angle at peak varus-valgus, a significant interaction was observed (F (2,26)=3.95, P=.03), the INT group increased more (61.58±11.14 to 69.07±1.53°) than the EXT group (P=.08). Differences between groups were found for peak varus-valgus moment (F (2,26)=4.81, P=.02) and ankle flexion-extension moment (F (2,26)=6.40, P<.01). No significant main effects for time were displayed. External or internal focused instructions could be beneficial in improving landing technique, which is promising as an external focus of attention requires less time from coaches and has therefore great potential in ACL injury prevention.
International journal of sports physical therapy, 2013
Current clinical outcome measurements may overestimate the long term success of anterior cruciate... more Current clinical outcome measurements may overestimate the long term success of anterior cruciate ligament reconstruction (ACLR). There is a need to understand biomechanics of the knee joint during daily activities. This systematic review provides a comprehensive overview of the literature related to gait in patients following ACLR. The purpose of this systematic review was to investigate the available literature and provide a comprehensive overview of kinematic and kinetic variables that present during gait in patients after ACLR. A literature search was performed in AMED, CINAHL, EMBASE, Medline and Scopus between January 2000 and October 2012. Inclusion criteria included articles written in English, German or Dutch, and those reporting on gait analysis in patients after ACLR. Kinematic and/or kinetic data of the uninjured and ACLR knee and healthy controls (CTRL) were outcome measurements of interest. Each study's methodological quality was assessed using the Critical Apprais...
Objectives: The purpose of this study was to determine the effect of an internal and external att... more Objectives: The purpose of this study was to determine the effect of an internal and external attentional focus on single leg hop jump distance and knee kinematics in patients after ACL reconstruction (ACLR). Design: Experimental. Setting: Outpatient physical therapy facility. Participants: Sixteen patients after ACLR. Main Outcome Measures: Patients received either an instruction with an internal focus or an external focus before performing a single leg hop jump. The jump distance, knee valgus angle at initial contact, peak knee valgus angle, knee flexion angle at initial contact, peak knee flexion angle, total ROM and time to peak angles for the injured and non-injured legs were recorded. A repeated measures MANOVA was used to determine significance between the experimental conditions with the primary outcome measures as dependent variables. Results: The external focus group had significant larger knee flexion angles at initial contact, peak knee flexion, total ROM and time to peak knee flexion for the injured legs.
Sports Orthopaedics and Traumatology Sport-Orthopädie - Sport-Traumatologie, 2006
ABSTRACT Die vollständige Wiederherstellung der Kniefunktion nach einer vorderen Kreuzbandläsion ... more ABSTRACT Die vollständige Wiederherstellung der Kniefunktion nach einer vorderen Kreuzbandläsion (VKB-Läsion) gelingt nicht immer. Eine der Ursachen dürfte die hohe und steile Transplantatorientierung der klassischen “isometrischen” VKB-Rekonstruktionstechnik sein, der Pivot-shift-Test bleibt häufig positiv. Die iso-anatomische VKB-Rekonstruktion platziert den femoralen Tunnel tief und zentral in die natürliche Insertion. Damit werden auf elegante und relativ einfache Art alle Vorteile erreicht, die Multi-Bündel-Rekonstruktionen für sich beanspruchen.
International journal of sports physical therapy, 2014
Fatigue has been shown to affect performance of hop tests in patients after anterior cruciate lig... more Fatigue has been shown to affect performance of hop tests in patients after anterior cruciate ligament reconstruction (ACLR) compared to uninjured controls (CTRL). This may render the hop test less sensitive in detecting landing errors. The primary purpose of this study was to investigate the effect of lower extremity fatigue on landing performance assessed with the Landing Error Scoring System (LESS) in patients after ACLR compared to a CTRL group. It is plausible that fatigue would have an effect on confidence and risk appraisal in the ACLR group. The secondary purpose was to determine the relationship between psychological responses and LESS scores after fatigue. Twelve patients following ACLR (6 males, 6 females) who were tested at 10 ± 2.4 months after surgery participated in the current study and were compared to 10 subjects in the control group (5 males, 5 females). Subjects performed a jump-landing task and the landing was assessed using the Landing Error Scoring System (LES...
The Journal of orthopaedic and sports physical therapy, Jan 27, 2015
Synopsis Primary anterior cruciate ligament (ACL) injury prevention programs effectively reduce A... more Synopsis Primary anterior cruciate ligament (ACL) injury prevention programs effectively reduce ACL injury risk on the short term. Despite these programs ACL injury incidence is still high, making it imperative that we continue to improve current prevention strategies. A potential limitation of current ACL injury prevention training may be a lack in the transfer of conscious, optimal movement strategies rehearsed during training sessions to automatic movements required for athletic activities and unanticipated events on the field. Instructional strategies with an internal attentional focus have traditionally been utilized, but may not be optimal for the acquisition of the control of complex motor skills required for sports. Conversely, external focus instructional strategies may enhance skill acquisition more efficiently and increase the transfer of improved motor skills to sports activities. The current manuscript will present insights gained from the motor learning domain that may...
Background. Anterior cruciate ligament (ACL) deficiency can be a major problem for athletes and s... more Background. Anterior cruciate ligament (ACL) deficiency can be a major problem for athletes and subsequent reconstruction of the ACL may be indicated if a conservative regimen has failed. After ACL reconstruction signs of abnormality in the use of the leg remain for a long time. It is expected that the landing after a single-leg hop for distance (horizontal hop) might give insight in the differences in kinematics and kinetics between uninjured legs and ACL-reconstructed legs. Before the ACL-reconstructed leg can be compared with the contralateral leg, knowledge of differences between legs of uninjured subjects is needed.
ABSTRACT Neuropsychological capabilities in athletes may be associated with a predisposition to a... more ABSTRACT Neuropsychological capabilities in athletes may be associated with a predisposition to anterior cruciate ligament (ACL) injuries. Assess differences between male and female athletes in jump-landing technique in relation to their neuropsychological capabilities. Experimental. Laboratory. 31 recreational athletes, free from lower extremity injuries, participated (females: n=16, age=21.0±1.71 years, mass=65.1±5.6 kg, height=174.2±68.9 cm; males n=15, age=22.3±2.2 years, mass=77.9±8.9 kg, height=185.7±78.7 cm). Reaction time (RT) under stress was measured. Furthermore, participants conducted anticipated (ANT) and unanticipated (UNANT) double-legged drop-jumps, followed by running at 4.5-5.5 m/sec 45° to the left, straight, or 45° to the right, depending on the light indication prior to landing on the force plates. RT and joint kinematics (trunk flexion-TF, ankle flexion-AF) and kinetics (knee abduction moment-KAM, ankle extension moment-AEM) at peak vertical ground reaction force (vGRF,N/kg). Moments are expressed as external moments (Nm/kg). Pearson product-moment correlation between RT and joint biomechanics. During UNANT, KAM became significantly larger (P=.010) in females (-0.37±0.1) than males (-0.16±0.1). TF was greater in the AT (29.7°±3.3°) than UNANT (46.1°±3.1°) regardless of gender (P<001). AEM was smaller in females (2.1±0.1) than males (2.6±0.1), (P=.001). AF was smaller (i.e., increased flexion) when running straight (80.8°±0.8°) compared to the left or right (84.6°±0.7°, P=.002 and 84.2°±0.8°, P=.008). vGRF was smaller when running straight (22.8±1.0) compared to the left or right (31.5±1.0, P<.001 and 28.8±1.0, P<.001). Significant correlations (r 0.5-0.8, P<.05) were seen between faster RT and greater hip and knee flexion angle and smaller KAM and knee abduction angle. Females reacted differently to UNANT in the frontal plane, potentially placing them at greater ACL injury risk. In the sagittal plane, females showed stiffer ankle landing. Further, a change in direction increased vGRF. Smaller knee flexion combined with smaller TF angles during UNANT, may increase loads at the knee. Lastly, neuropsychological characteristics seem to affect ACL injury risk.
External focus instructions have been shown to result in superior motor performance compared to i... more External focus instructions have been shown to result in superior motor performance compared to internal focus instructions. Using an EF may help to optimize current anterior cruciate ligament (ACL) injury prevention programs. The purpose of the current study was to investigate the effects of instructions on landing technique and performance by comparing an external focus (EF), internal focus (IF), video (VI) and control (CTRL) group. Subjects (age 22.50±1.62years, height 179.70±10.43cm, mass 73.98±12.68kg) were randomly assigned to IF (n=10), EF (n=10), VI (n=10) or CTRL group (n=10). Landing was assessed from a drop vertical jump (DVJ) in five sessions: pretest, two training blocks (TR1 and TR2) and directly after the training sessions (post test) and retention test 1week later. Group specific instructions were offered in TR1 and TR2. Landing technique was assessed with the Landing Error Scoring System (LESS) and jump height was taken as performance measure. The results show that ...
The purpose of this section is to present the general guidelines for rehabilitating an injured te... more The purpose of this section is to present the general guidelines for rehabilitating an injured tennis player. The focus is on treating the most common injury pattern of overhead athletes, ie, rotator cuff pathology with secondary bursitis and finally microtraumatic instability. The ...
This contribution presents an overview on the development of knee rehabilitation as considered fr... more This contribution presents an overview on the development of knee rehabilitation as considered from the training science and sensomotorics point-of-view. The first part deals with the development of modern, medical training therapy and its relation to training science. The increasing significance of quality management is pointed out. The second part of the contribution focuses on recent knowledge in sensomotorics and on still unanswered questions which will be of significance in coming years. With anterior cruciate injuries as an example, the patient is shown to reconstruct his own sensomotor system. It is shown that in future, in selecting the choice of clinical parameter, care must be taken to ensure they relate to function as a whole – in the given case, to gait.
The aims of the study were (1) to evaluate the leg asymmetry assessed with ground reaction forces... more The aims of the study were (1) to evaluate the leg asymmetry assessed with ground reaction forces (GRFs) during unilateral and bilateral movements of different knee loads in anterior cruciate ligament (ACL) reconstructed patients and (2) to investigate differences in leg asymmetry depending on the International Knee Documentation Committee Subjective Form (IKDC) in order to identify potential compensation strategies. The knee function of 50 ACL reconstructed (patella tendon) patients was examined at 31 ± 7 months after the surgery. GRFs were quantified during the sit-to-stand and stand-to-sit test, the step-up and step-down test, and the two- and one-leg vertical jump. Further, the IKDC score, the anterior-posterior knee laxity, and the concentric torque of the quadriceps and hamstring muscles were evaluated. Differences between the operated and non-operated leg were found in the knee laxity, the quadriceps torque, and GRFs. The patients with low IKDC scores demonstrated greater leg asymmetries in GRFs compared to the patients with high IKDC scores. ACL reconstructed patients showed GRF asymmetries during unilateral and bilateral movements of different knee loads. Three compensation strategies were found in patients with low subjective knee function: (1) a reduced eccentric load, (2) an inter-limb compensation during bilateral movements, and (3) the avoidance of high vertical impact forces. These compensation strategies may be indicative of a protective adaptation to avoid excessive ACL strain. GRF measurements are practicable and efficient tools to identify individual compensation strategies during early rehabilitation.
This study investigated exercise-induced effects of static stretching and playing soccer on anter... more This study investigated exercise-induced effects of static stretching and playing soccer on anterior tibial translation (ATT) of the knee joint. Randomized controlled trial. University biomechanics laboratory. Thirty-one athletes were randomly assigned into a stretching (26.9 ± 6.2 years, 1.77 ± 0.09 m, 67.9 ± 10.7 kg) and a control group (27.9 ± 7.4 years, 1.75 ± 0.08 m, 72.0 ± 14.9 kg). Thirty-one amateur soccer players in an additional soccer group (25.1 ± 5.6 years, 1.74 ± 0.10 m, 71.8 ± 14.8 kg). All participants had no history of knee injury requiring surgery and any previous knee ligament or cartilage injury. The stretching group performed 4 different static stretching exercises with a duration of 2 × 20 seconds interspersed with breaks of 10 seconds. The soccer group completed a 90-minute soccer-specific training program. The control group did not perform any physical activity for approximately 30 minutes. Anterior tibial translation was measured with the KT-1000 knee arthrometer at forces of 67 N, 89 N, and maximal manual force (Max) before and after the intervention. There was a significant increase in ATT after static stretching and playing soccer at all applied forces. Maximal manual testing revealed a mean increase of ATT after static stretching of 2.1 ± 1.6 mm (P < 0.0005) and after playing soccer of 1.0 ± 1.5 mm (P = 0.001). The ATT increase after static stretching at 67 and 89 N is significantly higher than in controls. At maximum manual testing, significant differences were evident between all groups. Static stretching and playing soccer increase ATT and may consequently influence mechanical factors of the anterior cruciate ligament. The ATT increase after static stretching was greater than after playing soccer. The observed increase in ATT after static stretching and playing soccer may be associated with changes in kinesthetic perception and sensorimotor control, activation of muscles, joint stability, overall performance, and higher injury risk.
Adding external focus of attention (EF, focus on the movement effect) may optimize current anteri... more Adding external focus of attention (EF, focus on the movement effect) may optimize current anterior cruciate ligament (ACL) injury prevention programmes. The purpose of the current study was to investigate the effects of an EF, by a visual stimulus and an internal focus, by a verbal stimulus during unexpected sidestep cutting in female and male athletes and how these effects remained over time. Ninety experienced basketball athletes performed sidestep cutting manoeuvres in three sessions (S1, S2 and S3). In this randomized controlled trial, athletes were allocated to three groups: visual (VIS), verbal (VER) and control (CTRL). Kinematics and kinetics were collected at the time of peak knee frontal plane moment. Males in the VIS group showed a larger vertical ground reaction force (S1: 25.4 ± 3.1 N/kg, S2: 25.8 ± 2.9 N/kg, S3: 25.2 ± 3.2 N/kg) and knee flexion moments (S1: -3.8 ± 0.9 Nm/kg, S2: -4.0 ± 1.2 Nm/kg, S3: -3.9 ± 1.3 Nm/kg) compared to the males in the VER and CTRL groups and to the females in the VIS group (p < 0.05). Additionally, the males in the VIS group reduced knee valgus moment and the females in the VER group reduced knee varus moment over time (n.s.). Male subjects clearly benefit from visual feedback. Females may need different feedback modes to learn a correct movement pattern. Sex-specific learning preferences may have to be acknowledged in day by day practice. Adding video instruction or feedback to regular training regimens when teaching athletes safe movement patterns and providing individual feedback might target suboptimal long-term results and optimize ACL injury prevention programmes. I.
ABSTRACT Anterior cruciate ligament (ACL) injury prevention programs have shown mixed results, wh... more ABSTRACT Anterior cruciate ligament (ACL) injury prevention programs have shown mixed results, which may be in part due to suboptimal training components. Determine effects of a prevention program with external and internal focus of attention on (potential) biomechanical risk factors for ACL injury. Pretest-posttest control group. Laboratory and field. 31 elite female soccer players participated. Exclusion criteria included previous ACL injury or current lower extremity injury. Two teams performed warm-up programs, including strength, agility, balance, plyometric, core and speed exercises twice a week for 12 weeks. One team received instructions to focus attention internally toward movements of the body (INT); another team received instructions to focus attention externally near the body (EXT). The control group (CON) performed their regular warming-up without specific instructions. Normalized external knee and ankle joint moments and joint angles on a two-legged jump-landing-rebound task. Results of 3x2 repeated measures ANOVA revealed significant group x time interaction for peak knee extension moment (F (2,23)=4.09, P=.03), the EXT group decreased more (-0.90±0.16 to -0.73±0.15 Nm/kg*m) than the CON group (P<.05). Regarding knee flexion angle at peak varus-valgus, a significant interaction was observed (F (2,26)=3.95, P=.03), the INT group increased more (61.58±11.14 to 69.07±1.53°) than the EXT group (P=.08). Differences between groups were found for peak varus-valgus moment (F (2,26)=4.81, P=.02) and ankle flexion-extension moment (F (2,26)=6.40, P<.01). No significant main effects for time were displayed. External or internal focused instructions could be beneficial in improving landing technique, which is promising as an external focus of attention requires less time from coaches and has therefore great potential in ACL injury prevention.
International journal of sports physical therapy, 2013
Current clinical outcome measurements may overestimate the long term success of anterior cruciate... more Current clinical outcome measurements may overestimate the long term success of anterior cruciate ligament reconstruction (ACLR). There is a need to understand biomechanics of the knee joint during daily activities. This systematic review provides a comprehensive overview of the literature related to gait in patients following ACLR. The purpose of this systematic review was to investigate the available literature and provide a comprehensive overview of kinematic and kinetic variables that present during gait in patients after ACLR. A literature search was performed in AMED, CINAHL, EMBASE, Medline and Scopus between January 2000 and October 2012. Inclusion criteria included articles written in English, German or Dutch, and those reporting on gait analysis in patients after ACLR. Kinematic and/or kinetic data of the uninjured and ACLR knee and healthy controls (CTRL) were outcome measurements of interest. Each study's methodological quality was assessed using the Critical Apprais...
Objectives: The purpose of this study was to determine the effect of an internal and external att... more Objectives: The purpose of this study was to determine the effect of an internal and external attentional focus on single leg hop jump distance and knee kinematics in patients after ACL reconstruction (ACLR). Design: Experimental. Setting: Outpatient physical therapy facility. Participants: Sixteen patients after ACLR. Main Outcome Measures: Patients received either an instruction with an internal focus or an external focus before performing a single leg hop jump. The jump distance, knee valgus angle at initial contact, peak knee valgus angle, knee flexion angle at initial contact, peak knee flexion angle, total ROM and time to peak angles for the injured and non-injured legs were recorded. A repeated measures MANOVA was used to determine significance between the experimental conditions with the primary outcome measures as dependent variables. Results: The external focus group had significant larger knee flexion angles at initial contact, peak knee flexion, total ROM and time to peak knee flexion for the injured legs.
Sports Orthopaedics and Traumatology Sport-Orthopädie - Sport-Traumatologie, 2006
ABSTRACT Die vollständige Wiederherstellung der Kniefunktion nach einer vorderen Kreuzbandläsion ... more ABSTRACT Die vollständige Wiederherstellung der Kniefunktion nach einer vorderen Kreuzbandläsion (VKB-Läsion) gelingt nicht immer. Eine der Ursachen dürfte die hohe und steile Transplantatorientierung der klassischen “isometrischen” VKB-Rekonstruktionstechnik sein, der Pivot-shift-Test bleibt häufig positiv. Die iso-anatomische VKB-Rekonstruktion platziert den femoralen Tunnel tief und zentral in die natürliche Insertion. Damit werden auf elegante und relativ einfache Art alle Vorteile erreicht, die Multi-Bündel-Rekonstruktionen für sich beanspruchen.
International journal of sports physical therapy, 2014
Fatigue has been shown to affect performance of hop tests in patients after anterior cruciate lig... more Fatigue has been shown to affect performance of hop tests in patients after anterior cruciate ligament reconstruction (ACLR) compared to uninjured controls (CTRL). This may render the hop test less sensitive in detecting landing errors. The primary purpose of this study was to investigate the effect of lower extremity fatigue on landing performance assessed with the Landing Error Scoring System (LESS) in patients after ACLR compared to a CTRL group. It is plausible that fatigue would have an effect on confidence and risk appraisal in the ACLR group. The secondary purpose was to determine the relationship between psychological responses and LESS scores after fatigue. Twelve patients following ACLR (6 males, 6 females) who were tested at 10 ± 2.4 months after surgery participated in the current study and were compared to 10 subjects in the control group (5 males, 5 females). Subjects performed a jump-landing task and the landing was assessed using the Landing Error Scoring System (LES...
The Journal of orthopaedic and sports physical therapy, Jan 27, 2015
Synopsis Primary anterior cruciate ligament (ACL) injury prevention programs effectively reduce A... more Synopsis Primary anterior cruciate ligament (ACL) injury prevention programs effectively reduce ACL injury risk on the short term. Despite these programs ACL injury incidence is still high, making it imperative that we continue to improve current prevention strategies. A potential limitation of current ACL injury prevention training may be a lack in the transfer of conscious, optimal movement strategies rehearsed during training sessions to automatic movements required for athletic activities and unanticipated events on the field. Instructional strategies with an internal attentional focus have traditionally been utilized, but may not be optimal for the acquisition of the control of complex motor skills required for sports. Conversely, external focus instructional strategies may enhance skill acquisition more efficiently and increase the transfer of improved motor skills to sports activities. The current manuscript will present insights gained from the motor learning domain that may...
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