Received his Master of Science in Physical Therapy from the University of Connecticut (USA) in 2000. Assistant professor at the department of Physical Performance at the Norwegian School of Sport Science (2005 to present) where he is currently enrolled in the PhD program. Research interests include biomechanics, motor control, athletic development and performance. Physiotherapist at the Norwegian Olympic Sport Center in Oslo. Involved in multiple innovation projects in the application of robotics to testing, training and rehabilitation. https://orcid.org/0000-0003-4971-6723
Background: Different tests for dynamic postural control; i.e., the ability to maintain a stable ... more Background: Different tests for dynamic postural control; i.e., the ability to maintain a stable base while completing a movement, are frequently used to assess functional and athletic performance. Current tests primarily target either the lower extremities or the trunk and the upper extremities. In addition, these tests have variable demands on functional mobility, which is defined as the combination of the range of motion (ROM) of multiple joints used to accomplish ecological tasks. Currently there are no tests of dynamic postural control that simultaneously impose three-dimensional mobility demands on the trunk, lower and upper extremities. The purpose of this thesis was to develop a new test of dynamic postural control to target these shortcomings and to establish 1) validity; 2) reliability; 3) the influence of potential covariates such as anthropometry, age, sex and level of physical activity; and 4) the influence on overhead athletic performance. Methods: The thesis is based on four different research projects that used an observational design with a total of 222 participants; these projects represent the development of the hand reach star excursion balance tests (HSEBT). Standardized testing procedures were developed by a group of experts, based on: 1) starting position; 2) task; 3) measurement; and 4) ending position, which served as content validity. In study I, criterion-related and construct validity were explored. Specifically, the magnitudes of joint movements used to assume maximum HSEBT reach positions were quantified using motion capture (Qualisys Oqus 400 cameras, Qualisys AB, Gothenburg, Sweden) and compared to joint movements in the comparable star excursion balance test (SEBT) and normative ROM values. Criterion-related (concurrent) validity was established by comparing reach measurements calculated from motion capture data to those visually obtained using Bland Altman and correlational analysis. Construct validity was assessed by correlating outcome measurements (reach, composite scores and area calculations) from the HSEBT with the comparable SEBT. In study II, inter-rater and testretest reliability was assessed from the outcome measurements of three experienced testers using intraclass correlation coefficients (ICC), with the calculation of stability measurements (standard error or measurement and coefficient of variation) and minimal detectable change. The influence of anthropometry, age, sex and level of physical activity was explored in study III. Stepwise linear regression was used to determine the influence of these factors on reach measurements. Independent samples t-tests were used to determine betweengroup (age, sex and level of physical activity) differences with calculation of effect sizes and group difference comparisons to minimal detectable change values (study II). The influence of HSEBT reach measurements on athletic performance (overhead team handball throwing) in an elite female population was explored for both throwing velocity, calculated from motion capture data, and accuracy, via mean radial error calculated from video records, using Pearson correlational analysis. Main results: The HSEBT elicited significantly greater joint movements than the SEBT in 18 out of 22 joint movement comparisons. The magnitude of these joint movements was comparable to the ranges of normative ROM values for 8 out of 22 joint movements. Excellent correlations were observed between visually observed and calculated reach measurements from motion capture data for 18 out of 20 tests (r ≥ 0.90) with a shared variance that ranged from 81 to 97%. For the remaining two tests good correlations were observed (r = .79 and .89). The fixed biases observed (range = 2.2 to 12.8 cm, −6.0 to 11.2° and 23.7%) can be partially explained by the methods used to calculate reach measurements. Different composite and area scores for the HSEBT and SEBT had variable correlations (range r = .269 to .823), with a wider range of observed values for the individual reaches (range r = -.182 to .822). The strongest correlations were observed for the anterior composite, area and reach measurement comparisons (range r = .515 to .823). In Study II moderate to high test-retest reliability was observed for 19 out of 20 reaches (range ICC = 0.80 to 0.96). The inter-rater reliability was high for all reaches (range ICC = 0.90 to 0.98). Minimal detectable change values ranged from 0.9–7.9 cm and 4.7–7.2° for all reaches. Wingspan (study III) explained 34.6 and 11.7% of the variance of two HSEBT reaches. When normalized (% of wingspan) the same reaches were influenced by age, sex and level of physical activity with significant between-group differences, and moderate effect sizes (range d = .50 to .72). In addition, one non-normalized reach was influenced by age and level of physical activity (range d = .55 to .75). HSEBT reach measurements are not correlated with throwing velocity (range r = -.530 to .395), but with mean…
Static measures of range of motion (ROM) are used extensively to determine flexibility. These mea... more Static measures of range of motion (ROM) are used extensively to determine flexibility. These measures are often used to determine if flexibility training is indicated or not since it is thought that these measures reflect functional performance. The purpose of this study was to determine if static flexibility measures predict ROM during running. This was part of a larger project where the main purpose was to look at the influence of flexibility training on running economy, kinematic characteristics and stiffness. Methods: 17 subjects divided into a training group (TRA, n = 8) and a control group (CON, n = 9) were tested before (PRE) and after (POST) the implementation of a flexibility training program which lasted 6 weeks. All static measures were obtained by one experienced physical therapist using a hand-held goniometer. The measures included ankle dorsiflexion and hip extension (Thomas test). Running kinematics were recorded using an 8 camera Qualisys motion analysis system with...
Non-contact anterior cruciate ligament injuries typically occur during cutting maneuvers and are ... more Non-contact anterior cruciate ligament injuries typically occur during cutting maneuvers and are associated with high peak knee abduction moments (KAM) within early stance. To screen athletes for injury risk or quantify the efficacy of prevention programs, it may be necessary to design tasks that mimic game situations. Thus, this study compared KAMs and ranking consistency of female handball players in three sport-specific fake-and-cut tasks of increasing complexity. The biomechanics of female handball players (n = 51, mean ± SD: 66.9 ± 7.8 kg, 1.74 ± 0.06 m, 19.2 ± 3.4 years) were recorded with a 3D motion capture system and force plates during three standardized fake-and-cut tasks. Task 1 was designed as a simple pre-planned cut, task 2 included catching a ball before a pre-planned cut in front of a static defender, and task 3 was designed as an unanticipated cut with three dynamic defenders involved. Inverse dynamics were used to calculate peak KAM within the first 100 ms of stan...
Rapid horizontal accelerations and decelerations are crucial events enabling the changes of veloc... more Rapid horizontal accelerations and decelerations are crucial events enabling the changes of velocity and direction integral to sports involving random intermittent multi-directional movements. However, relative to horizontal acceleration, there have been considerably fewer scientific investigations into the biomechanical and neuromuscular demands of horizontal deceleration and the qualities underpinning horizontal deceleration performance. Accordingly, the aims of this review article are to: (1) conduct an evidence-based review of the biomechanical demands of horizontal deceleration and (2) identify biomechanical and neuromuscular performance determinants of horizontal deceleration, with the aim of outlining relevant performance implications for random intermittent multi-directional sports. We highlight that horizontal decelerations have a unique ground reaction force profile, characterised by high-impact peak forces and loading rates. The highest magnitude of these forces occurs du...
The aim of this study was to determine validity of velocity measurements of a motorized resistanc... more The aim of this study was to determine validity of velocity measurements of a motorized resistance device (MRD) during change of direction (CoD). Eight male (age: 22.1 ± 4.2 yrs; weight: 83.3 ± 17.1 kg; height: 181.6 ± 12.6 cm) and three female participants (age: 21.7 ± 1.5 yrs; mass: 69.7 ± 2.4 kg; height: 167.0 ± 3.6 cm) completed the modified 505 CoD test (m505) with turning off the left and right foot while exposed to external loads (3, 6, and 9 kg) provided by the MRD. Three-dimensional kinematic data were measured (200 Hz) for all tests using a full-body marker set with an additional marker placed on the pulley used to attach the carabiner (CAR) at the end of the line from the MRD to the participant. Average velocity of overall center of mass (COMvel), pelvis (COMpelvis_vel), and pulley (CARvel) was then calculated and compared to the velocity measured by MRD (MRDvel) in 0.5 s intervals 1.5 s before and after CoD. Average velocities from these intervals were then compared usin...
The relationship between dynamic postural control, functional mobility and team handball throwing... more The relationship between dynamic postural control, functional mobility and team handball throwing performance, velocity and accuracy, is largely unknown. The hand reach star excursion balance test (HSEBT) is a full kinetic chain assessment tool of these factors. Specifically, L135 and R135 (extension) reaches elicit joint movement combinations similar to the cocking and acceleration phase, while the L45 and R45 (flexion) reaches elicit joint movement combinations similar to the follow-through. The purpose of this study was to determine if specific HSEBT reach measures correlate with team handball throwing performance. Eleven elite female team handball players (21.7 ± 1.8 years; 71.3 ± 9.6 kg; 1.75 ± 0.07 m) executed selected HSEBT reaches before performing five valid step-up overhead throws (1x1m target) from which throwing velocity (motion capture) and accuracy (mean radial error) were quantified. Significant relationships between HSEBT measures and mean radial error, but not throw...
The purpose of the present study was to establish relationships between sprint front crawl perfor... more The purpose of the present study was to establish relationships between sprint front crawl performance and a swimming load-velocity profile. Fourteen male national-level swimmers performed 50 m front crawl and semi-tethered swimming with three progressive loads. The 50 m performance was recorded with a multi-camera system, with which two-dimensional head displacement and the beginning of each arm-stroke motion were quantified. Forward velocity (V50m), stroke length (SL) and frequency (SF) were quantified for each cycle, and the mean value of all cycles, excluding the first and last cycles, was used for the analysis. From the semi-tethered swimming test, the mean velocity during three stroke cycles in mid-pool was calculated and plotted as a function of the external load, and a linear regression line expressing the relationship between the load and velocity was established for each swimmer. The intercepts between the established line and the axes of the plot were defined as theoretic...
International Journal of Sports Physiology and Performance, 2020
Purpose: To analyze and compare the effects of 4 different resisted sprint training (RST) modalit... more Purpose: To analyze and compare the effects of 4 different resisted sprint training (RST) modalities on youth soccer players’ performance after 8 weeks of training. Methods: Forty-eight youth soccer players were first randomly assigned to 4 groups and only then completed 8 weeks of RST: horizontal resisted sprint, vertical resisted sprint (VRS), combined resisted sprint, and unresisted sprint. Performance in horizontal and vertical jumps, sprint, and change of direction (COD) ability were assessed 1 week before and after the training intervention. Magnitude-based inference analysis was performed for calculating within-group pre–post differences. In addition, an analysis of covariance test was performed for between-group comparison, using the pretest values as covariates. After that, the analysis of covariance P values and the effect statistic were transformed to magnitude-based inference. Results: Within-group outcomes showed that all resisted training modalities experienced improve...
The purpose of this study was to establish the relationships between 50 m sprint swimming perform... more The purpose of this study was to establish the relationships between 50 m sprint swimming performance and variables acquired from a swimming load-velocity profile established by semi-tethered butterfly swimming. Twelve male elite swimmers participated in the present study and performed 50 m sprint and semi-tethered butterfly swimming with different loads. The mean velocity among all upper-limb cycles was obtained from the 50 m swimming (race velocity), and maximum load and velocity were predicted from the load-velocity profile established by the semi-tethered swimming test. There was a very large correlation (r=0.885, p<0.01) and a high intra-class correlation (0.844, p<0.001) between the race velocity and the predicted maximum velocity. Significant correlations were also observed between the predicted maximum load and the 50 m time as well as the race velocity (r=− 0.624 and 0.556, respectively, both p<0.05), which imply that an ability to achieve a large tethered swimming...
Core stability is important to many functional and athletic tasks. Motion variability has been pr... more Core stability is important to many functional and athletic tasks. Motion variability has been proposed as a measure to characterize core stability. Based on motor learning theories, the current study hypothesized that variability and stability of core movements show a U-shaped relationship and further investigated whether functional range of motion (“mobility”) or speed of motion affect this relationship. Twenty-four healthy subjects performed 20 cycles of two different unilateral hand reaching tasks for both the left and right hand under stable and unstable conditions. Reach targets were positioned to trigger large core movements. Specifically, the anterior target was positioned midsagittal at arm length´s distance and hip height. Two posterior targets (60 degrees posterior to neutral stance frontal plane) on both the left and right side were high (at arm length distance and height with accrued 10 cm) and low (arm length distance at hip height). Kinematic data were recorded and ...
In the current study we investigated the effects of resisted sprint training on sprinting perform... more In the current study we investigated the effects of resisted sprint training on sprinting performance and underlying mechanical parameters (force-velocity-power profile) based on two different training protocols: (i) loads that represented maximum power output (Lopt) and a 50% decrease in maximum unresisted sprinting velocity and (ii) lighter loads that represented a 10% decrease in maximum unresisted sprinting velocity, as drawn from previous research (L10). Soccer [n = 15 male] and rugby [n = 21; 9 male and 12 female] club-level athletes were individually assessed for horizontal force-velocity and load-velocity profiles using a battery of resisted sprints, sled or robotic resistance respectively. Athletes then performed a 12-session resisted (10 × 20-m; and pre- post-profiling) sprint training intervention following the L10 or Lopt protocol. Both L10 and Lopt training protocols had minor effects on sprinting performance (average of -1.4 to -2.3% split-times respectively), and prov...
Tests of dynamic postural control eliciting full-body three-dimensional joint movements in a syst... more Tests of dynamic postural control eliciting full-body three-dimensional joint movements in a systematic manner are scarce. The well-established star excursion balance test (SEBT) elicits primarily three-dimensional lower extremity joint movements with minimal trunk and no upper extremity joint movements. In response to these shortcomings we created the hand reach star excursion balance test (HSEBT) based on the SEBT reach directions. The aims of the current study were to 1) compare HSEBT and SEBT measurements, 2) compare joint movements elicited by the HSEBT to both SEBT joint movements and normative range of motion values published in the literature. Ten SEBT and HSEBT reaches for each foot were obtained while capturing full-body kinematics in twenty recreationally active healthy male subjects. HSEBT and SEBT areas and composite scores (sum of reaches) for total, anterior and posterior subsections and individual reaches were correlated. Total reach score comparisons showed fair to ...
Background: Different tests for dynamic postural control; i.e., the ability to maintain a stable ... more Background: Different tests for dynamic postural control; i.e., the ability to maintain a stable base while completing a movement, are frequently used to assess functional and athletic performance. Current tests primarily target either the lower extremities or the trunk and the upper extremities. In addition, these tests have variable demands on functional mobility, which is defined as the combination of the range of motion (ROM) of multiple joints used to accomplish ecological tasks. Currently there are no tests of dynamic postural control that simultaneously impose three-dimensional mobility demands on the trunk, lower and upper extremities. The purpose of this thesis was to develop a new test of dynamic postural control to target these shortcomings and to establish 1) validity; 2) reliability; 3) the influence of potential covariates such as anthropometry, age, sex and level of physical activity; and 4) the influence on overhead athletic performance. Methods: The thesis is based on four different research projects that used an observational design with a total of 222 participants; these projects represent the development of the hand reach star excursion balance tests (HSEBT). Standardized testing procedures were developed by a group of experts, based on: 1) starting position; 2) task; 3) measurement; and 4) ending position, which served as content validity. In study I, criterion-related and construct validity were explored. Specifically, the magnitudes of joint movements used to assume maximum HSEBT reach positions were quantified using motion capture (Qualisys Oqus 400 cameras, Qualisys AB, Gothenburg, Sweden) and compared to joint movements in the comparable star excursion balance test (SEBT) and normative ROM values. Criterion-related (concurrent) validity was established by comparing reach measurements calculated from motion capture data to those visually obtained using Bland Altman and correlational analysis. Construct validity was assessed by correlating outcome measurements (reach, composite scores and area calculations) from the HSEBT with the comparable SEBT. In study II, inter-rater and testretest reliability was assessed from the outcome measurements of three experienced testers using intraclass correlation coefficients (ICC), with the calculation of stability measurements (standard error or measurement and coefficient of variation) and minimal detectable change. The influence of anthropometry, age, sex and level of physical activity was explored in study III. Stepwise linear regression was used to determine the influence of these factors on reach measurements. Independent samples t-tests were used to determine betweengroup (age, sex and level of physical activity) differences with calculation of effect sizes and group difference comparisons to minimal detectable change values (study II). The influence of HSEBT reach measurements on athletic performance (overhead team handball throwing) in an elite female population was explored for both throwing velocity, calculated from motion capture data, and accuracy, via mean radial error calculated from video records, using Pearson correlational analysis. Main results: The HSEBT elicited significantly greater joint movements than the SEBT in 18 out of 22 joint movement comparisons. The magnitude of these joint movements was comparable to the ranges of normative ROM values for 8 out of 22 joint movements. Excellent correlations were observed between visually observed and calculated reach measurements from motion capture data for 18 out of 20 tests (r ≥ 0.90) with a shared variance that ranged from 81 to 97%. For the remaining two tests good correlations were observed (r = .79 and .89). The fixed biases observed (range = 2.2 to 12.8 cm, −6.0 to 11.2° and 23.7%) can be partially explained by the methods used to calculate reach measurements. Different composite and area scores for the HSEBT and SEBT had variable correlations (range r = .269 to .823), with a wider range of observed values for the individual reaches (range r = -.182 to .822). The strongest correlations were observed for the anterior composite, area and reach measurement comparisons (range r = .515 to .823). In Study II moderate to high test-retest reliability was observed for 19 out of 20 reaches (range ICC = 0.80 to 0.96). The inter-rater reliability was high for all reaches (range ICC = 0.90 to 0.98). Minimal detectable change values ranged from 0.9–7.9 cm and 4.7–7.2° for all reaches. Wingspan (study III) explained 34.6 and 11.7% of the variance of two HSEBT reaches. When normalized (% of wingspan) the same reaches were influenced by age, sex and level of physical activity with significant between-group differences, and moderate effect sizes (range d = .50 to .72). In addition, one non-normalized reach was influenced by age and level of physical activity (range d = .55 to .75). HSEBT reach measurements are not correlated with throwing velocity (range r = -.530 to .395), but with mean…
Static measures of range of motion (ROM) are used extensively to determine flexibility. These mea... more Static measures of range of motion (ROM) are used extensively to determine flexibility. These measures are often used to determine if flexibility training is indicated or not since it is thought that these measures reflect functional performance. The purpose of this study was to determine if static flexibility measures predict ROM during running. This was part of a larger project where the main purpose was to look at the influence of flexibility training on running economy, kinematic characteristics and stiffness. Methods: 17 subjects divided into a training group (TRA, n = 8) and a control group (CON, n = 9) were tested before (PRE) and after (POST) the implementation of a flexibility training program which lasted 6 weeks. All static measures were obtained by one experienced physical therapist using a hand-held goniometer. The measures included ankle dorsiflexion and hip extension (Thomas test). Running kinematics were recorded using an 8 camera Qualisys motion analysis system with...
Non-contact anterior cruciate ligament injuries typically occur during cutting maneuvers and are ... more Non-contact anterior cruciate ligament injuries typically occur during cutting maneuvers and are associated with high peak knee abduction moments (KAM) within early stance. To screen athletes for injury risk or quantify the efficacy of prevention programs, it may be necessary to design tasks that mimic game situations. Thus, this study compared KAMs and ranking consistency of female handball players in three sport-specific fake-and-cut tasks of increasing complexity. The biomechanics of female handball players (n = 51, mean ± SD: 66.9 ± 7.8 kg, 1.74 ± 0.06 m, 19.2 ± 3.4 years) were recorded with a 3D motion capture system and force plates during three standardized fake-and-cut tasks. Task 1 was designed as a simple pre-planned cut, task 2 included catching a ball before a pre-planned cut in front of a static defender, and task 3 was designed as an unanticipated cut with three dynamic defenders involved. Inverse dynamics were used to calculate peak KAM within the first 100 ms of stan...
Rapid horizontal accelerations and decelerations are crucial events enabling the changes of veloc... more Rapid horizontal accelerations and decelerations are crucial events enabling the changes of velocity and direction integral to sports involving random intermittent multi-directional movements. However, relative to horizontal acceleration, there have been considerably fewer scientific investigations into the biomechanical and neuromuscular demands of horizontal deceleration and the qualities underpinning horizontal deceleration performance. Accordingly, the aims of this review article are to: (1) conduct an evidence-based review of the biomechanical demands of horizontal deceleration and (2) identify biomechanical and neuromuscular performance determinants of horizontal deceleration, with the aim of outlining relevant performance implications for random intermittent multi-directional sports. We highlight that horizontal decelerations have a unique ground reaction force profile, characterised by high-impact peak forces and loading rates. The highest magnitude of these forces occurs du...
The aim of this study was to determine validity of velocity measurements of a motorized resistanc... more The aim of this study was to determine validity of velocity measurements of a motorized resistance device (MRD) during change of direction (CoD). Eight male (age: 22.1 ± 4.2 yrs; weight: 83.3 ± 17.1 kg; height: 181.6 ± 12.6 cm) and three female participants (age: 21.7 ± 1.5 yrs; mass: 69.7 ± 2.4 kg; height: 167.0 ± 3.6 cm) completed the modified 505 CoD test (m505) with turning off the left and right foot while exposed to external loads (3, 6, and 9 kg) provided by the MRD. Three-dimensional kinematic data were measured (200 Hz) for all tests using a full-body marker set with an additional marker placed on the pulley used to attach the carabiner (CAR) at the end of the line from the MRD to the participant. Average velocity of overall center of mass (COMvel), pelvis (COMpelvis_vel), and pulley (CARvel) was then calculated and compared to the velocity measured by MRD (MRDvel) in 0.5 s intervals 1.5 s before and after CoD. Average velocities from these intervals were then compared usin...
The relationship between dynamic postural control, functional mobility and team handball throwing... more The relationship between dynamic postural control, functional mobility and team handball throwing performance, velocity and accuracy, is largely unknown. The hand reach star excursion balance test (HSEBT) is a full kinetic chain assessment tool of these factors. Specifically, L135 and R135 (extension) reaches elicit joint movement combinations similar to the cocking and acceleration phase, while the L45 and R45 (flexion) reaches elicit joint movement combinations similar to the follow-through. The purpose of this study was to determine if specific HSEBT reach measures correlate with team handball throwing performance. Eleven elite female team handball players (21.7 ± 1.8 years; 71.3 ± 9.6 kg; 1.75 ± 0.07 m) executed selected HSEBT reaches before performing five valid step-up overhead throws (1x1m target) from which throwing velocity (motion capture) and accuracy (mean radial error) were quantified. Significant relationships between HSEBT measures and mean radial error, but not throw...
The purpose of the present study was to establish relationships between sprint front crawl perfor... more The purpose of the present study was to establish relationships between sprint front crawl performance and a swimming load-velocity profile. Fourteen male national-level swimmers performed 50 m front crawl and semi-tethered swimming with three progressive loads. The 50 m performance was recorded with a multi-camera system, with which two-dimensional head displacement and the beginning of each arm-stroke motion were quantified. Forward velocity (V50m), stroke length (SL) and frequency (SF) were quantified for each cycle, and the mean value of all cycles, excluding the first and last cycles, was used for the analysis. From the semi-tethered swimming test, the mean velocity during three stroke cycles in mid-pool was calculated and plotted as a function of the external load, and a linear regression line expressing the relationship between the load and velocity was established for each swimmer. The intercepts between the established line and the axes of the plot were defined as theoretic...
International Journal of Sports Physiology and Performance, 2020
Purpose: To analyze and compare the effects of 4 different resisted sprint training (RST) modalit... more Purpose: To analyze and compare the effects of 4 different resisted sprint training (RST) modalities on youth soccer players’ performance after 8 weeks of training. Methods: Forty-eight youth soccer players were first randomly assigned to 4 groups and only then completed 8 weeks of RST: horizontal resisted sprint, vertical resisted sprint (VRS), combined resisted sprint, and unresisted sprint. Performance in horizontal and vertical jumps, sprint, and change of direction (COD) ability were assessed 1 week before and after the training intervention. Magnitude-based inference analysis was performed for calculating within-group pre–post differences. In addition, an analysis of covariance test was performed for between-group comparison, using the pretest values as covariates. After that, the analysis of covariance P values and the effect statistic were transformed to magnitude-based inference. Results: Within-group outcomes showed that all resisted training modalities experienced improve...
The purpose of this study was to establish the relationships between 50 m sprint swimming perform... more The purpose of this study was to establish the relationships between 50 m sprint swimming performance and variables acquired from a swimming load-velocity profile established by semi-tethered butterfly swimming. Twelve male elite swimmers participated in the present study and performed 50 m sprint and semi-tethered butterfly swimming with different loads. The mean velocity among all upper-limb cycles was obtained from the 50 m swimming (race velocity), and maximum load and velocity were predicted from the load-velocity profile established by the semi-tethered swimming test. There was a very large correlation (r=0.885, p<0.01) and a high intra-class correlation (0.844, p<0.001) between the race velocity and the predicted maximum velocity. Significant correlations were also observed between the predicted maximum load and the 50 m time as well as the race velocity (r=− 0.624 and 0.556, respectively, both p<0.05), which imply that an ability to achieve a large tethered swimming...
Core stability is important to many functional and athletic tasks. Motion variability has been pr... more Core stability is important to many functional and athletic tasks. Motion variability has been proposed as a measure to characterize core stability. Based on motor learning theories, the current study hypothesized that variability and stability of core movements show a U-shaped relationship and further investigated whether functional range of motion (“mobility”) or speed of motion affect this relationship. Twenty-four healthy subjects performed 20 cycles of two different unilateral hand reaching tasks for both the left and right hand under stable and unstable conditions. Reach targets were positioned to trigger large core movements. Specifically, the anterior target was positioned midsagittal at arm length´s distance and hip height. Two posterior targets (60 degrees posterior to neutral stance frontal plane) on both the left and right side were high (at arm length distance and height with accrued 10 cm) and low (arm length distance at hip height). Kinematic data were recorded and ...
In the current study we investigated the effects of resisted sprint training on sprinting perform... more In the current study we investigated the effects of resisted sprint training on sprinting performance and underlying mechanical parameters (force-velocity-power profile) based on two different training protocols: (i) loads that represented maximum power output (Lopt) and a 50% decrease in maximum unresisted sprinting velocity and (ii) lighter loads that represented a 10% decrease in maximum unresisted sprinting velocity, as drawn from previous research (L10). Soccer [n = 15 male] and rugby [n = 21; 9 male and 12 female] club-level athletes were individually assessed for horizontal force-velocity and load-velocity profiles using a battery of resisted sprints, sled or robotic resistance respectively. Athletes then performed a 12-session resisted (10 × 20-m; and pre- post-profiling) sprint training intervention following the L10 or Lopt protocol. Both L10 and Lopt training protocols had minor effects on sprinting performance (average of -1.4 to -2.3% split-times respectively), and prov...
Tests of dynamic postural control eliciting full-body three-dimensional joint movements in a syst... more Tests of dynamic postural control eliciting full-body three-dimensional joint movements in a systematic manner are scarce. The well-established star excursion balance test (SEBT) elicits primarily three-dimensional lower extremity joint movements with minimal trunk and no upper extremity joint movements. In response to these shortcomings we created the hand reach star excursion balance test (HSEBT) based on the SEBT reach directions. The aims of the current study were to 1) compare HSEBT and SEBT measurements, 2) compare joint movements elicited by the HSEBT to both SEBT joint movements and normative range of motion values published in the literature. Ten SEBT and HSEBT reaches for each foot were obtained while capturing full-body kinematics in twenty recreationally active healthy male subjects. HSEBT and SEBT areas and composite scores (sum of reaches) for total, anterior and posterior subsections and individual reaches were correlated. Total reach score comparisons showed fair to ...
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Papers by Ola Eriksrud